EPA - 908/ 5-80-003 DRAFT ENVIRONMENTAL IMPACT STATEMENT IMPACT OF CANADTAN POWER PLANT DEVELOPMENT AND FLOW APPORTIONMENT ON THE POPLAR RIVER BASIN EPA Prepared by U.S. Environmental Protection Agency Montana Office Region VIII Federal Building Helena, Montana 59601 ApDroved b’ er 1 iams Date: eg al Administrator ------- Lf J7 3 SUMMARY Draft (X) Final ( ) Environmental Statement Type of Action : Administrative (X) Legislative ( ) 2. Brief Description of Action : A coal-fired power plant is currently being constructed by Saskatchewan Power Corporation on the East Fork of the Poplar River about 4 miles north of the International Boundary. Since the power plant and associated cooling water reservoir will result in a consumptive water use and will modify the natural transboundary flow of the Poplar River, it is antici— pateci that a flow apportionment agreement between the U. S. and Canada will be established. This Environmental Impact Stateement has been prepared to address the impacts of several flow apportionment alternatives in addition to other potential impacts of the power plant on the U. S. part of the Poplar River Basin. 3. Summary of Environmental Impacts : The Poplar River flows will be reduced under conditions of the recommended apportionment up to 50 percent of the natural flow in the West Fork and at least 60 percent of the natural flow on the Middle Fork. Summer flows in the East Fork will be about 35 to 65 percent less with one power plant operating and up to 80 percent less with four power plants oper- ating. These reduced flows will result in less water being available for future irrigation expansion. These lower flows may also impact furbearers, waterfowl, fish and other organisms now using these riverene habitats. Water quality will become lower than at present with total dissolved solids levels increasing. The highest concentrations of airborne pollutants will occur southeast of the proposed power plant. The highest annual mean concentrations of S02, NOx and particulates were 4.8, 1.6 and 0.4 ug/rn 3 , respectively, for a 1200 MWe plant. The predicted concentrations were less than the U. S. National Ambient Air Quality Standards and the Montana Ambient Air Quality Standards for 1-hour, 3—hour, 24—hours, and the annual mean. The maximum increases in $02 concentrations predicted from 24 to 62 percent of maximum allowable increases for Class II areas. The particulate loading in the impact area was only about 2 percent of maximum allowable limits. Fumigation under very stable conditions could result in S02 concentrations between 2000 and 4000 ug/m3 at a distance of 10 to 20 km downwind of a 1200 MWe plant. If a concentration of 4000 ug/m 3 persisted for 30 minutes, the allowable 3 hour increase of 512 ug/rn 3 for Class II areas would be exceeded. Under more typical conditions the $02 concentrations were estimated to be less than 1850 ug/m 3 . The impact of fumigation events would be minimal because of the small area affected by one event and the short time period (less than 45 minutes). Moreover, the frequency of occurrence is estimated as 11.1 and 35-45 percent for the very stable and typical atmospheric conditions, respectively. The predicted S02 concentrations with two 300 MWe units and no S02 control would exceed the Class I PSD regulations at the proposed Class I area of the Fort Peck Indian Reservation but not at the Medicine Lake National Wildlife ------- -2- Refuge. The regulations could be met at the Fort Peck Indian Reservation with 60 percent control for two 300 MWe units and 90 percent control for four 300 MWe units. Comparison of the predicted concentrations of SO 2 , NO and particulates with acute and chronic threshold limits for selected plant species indicated no detectable impacts on the terrestrial vegetation. No impacts were predicted due to accumulation of trace metals in soils. Thus, no impacts were predicted on any rare and endangered species. Expenditures of Canadian workers in Daniels County have resulted in direct and secondary impacts of $216,000 to $324,000, representing 6.3 to 9.5 percent of total retail sales. Secondary impacts of $53,000 to $79,000 were projected for Roosevelt County. Analysis of the secondary effects of flow apportionment resulting in reduced development of irrigated land and poorer quality irrigation water indicates that in both Daniels and Roosevelt counties the losses of personal income (due to changes in farm income and secondary impacts) amount to about 1 percent in the year 2000. In 1985, the projected personal income changes are -0.7 percent and +0.3 percent for Daniels and Roosevelt counties, respectively. The 1985 apportionment levels result in maximum reductions of farm proprietors’ income of 1.5 percent and less than 3.1 percent for Daniels and Roosevelt counties, respectively. These respective impacts increase to 2.2 percent and 6 percent at the year 2000 level of development. 4. Alternatives Considered : A. Air Quality - various levels of control for S02 (flue gas desulfuri- zation) and particulates are evaluated in Chapter 3. B. Various flow apportionment regimes have been evaluated. An apportionment of waters on a 50% Canada - 50% U.S. basis may be approved. 5. Con nents Requested From the Following : see attachment *Note - Only those who supply substantive comments on the draft EIS will be sent copies of the final EIS. 6. Date Draft EIS Made Available to EPA and the Public : AUG 15 1980 ------- Comments on the Draft Environmental Impact Statement will be requested from the following: International International Joint Cornniision International Poplar River Water Quality Board Canada Province of Saskatchewan Saskatchewan Power Corporation Congressional U. S. Senator John Meicher U. S. Senator Max Baucus U. S. Representative Ron Marlene Montana Governor of Montana Lt. Governor of Montana Department of Agriculture Cooperative Extension Service Department of Community Affairs Department of Health and Environmental Sciences Department of Fish, Game and Parks Department of Natural Resources and Conservation Environmental Quality Council Historical Society Old West Regional Commission Federal U.S. Department of State Advisory Council on Historic Preservation Army Corps of Engineers Department of Agriculture Soil Conservation Service Department of Comerce Department of the Interior Bureau of Indian Affairs Bureau of Land Management Bureau of Mines Bureau of Outdoor Recreation Bureau of Reclamation Fish and Wildlife Service Geological Survey Heritage Conservation and Recreation Service ------- —2— Federal (Continued) Missouri River Basin Coninission National Park Service Department of Housing and Urban Development Department of Health Education and Welfare Local Government Sheridan County Comissioners Daniels County Comission Roosevelt County Commission Town of Scobey Town of Plentywood Town of Wolf Point Town of Poplar Other Organizations and Individuals Fort Peck Indian Reservation Northern Plains Resource Council Three Corners Boundary Association Environmental Information Center Montana Wildlife Federation National Wildlife Federation Friends of the Earth Trout Unlimited Ducks Unlimited Daniels County WIFE - Zelpha Danielson - Scobey Dale Chabot -Scobey Lowell Burgett - Scobey Jim Sims - Soil Science Lab, MSU, Bozeman Delmer Safty - Whitetail Dr. Merele D. Fitz - Scobey Tittinger Brothers - Scobey Environmental Studies Lab., U. of M. - Missoula Glasgow Public Library Plentywood Public Library Scobey Public Library Wolf Point Public Library Hugh Baker — Whitetail Dr. Robert R. Bell, DVM, Culbertsori Charles Cassidy - Scobey Bill Cromwell - Flaxville Ken Lee - DVM, Scobey Farver Brothers - Scobey Lyle Hang - Scobey Hellickson Brothers, Inc. - Scobey Gordon Holte - Plentywood ------- -3— Other Organizations and Individuals (Continued) Lee Hurnbert - Scobey Art Lund - Scobey Dennis Nathe - Redstone Lee Rovig - Outlook Robert Schneekloth - Redstone Ted Skornogoski - Scobey Ron Stoneberg — Circle Bill Tande - Scobey Boyd Tymofichuk - Scobey Eddie Lund - Scobey Daniels County Leader - Scobey Plentywood Herald Glasgow Courier Wotanian - Poplar Wolf Point Herald ------- DRAFT ENVIRONMENTAL IMPACT STATEMENT IMPACT OF CANADIAN POWER PLANT DEVELOPMENT AND FLOW APPORTIONMENT ON THE POPLAR RIVER BASIN U.S. Environmental Protection Agency Montana Office Region 8 Helena, Montana Prepared with assistance of Tetra Tech staff Tetra Tech, Incorporated 3746 Mt. Diablo Boulevard, Suite 300 Lafayette, California 94549 (415) 283-3771 EPA Contract No. 68-O1- 873 Tetra Tech Report No. TC-3254 EPA 908/80-003 JULY 1980 ------- TABLE OF CONTENTS 1. SUM 1ARY 1.1 WATER QUANTITY IMPACTS 1.2 WATER QUALITY IMPACTS 1.3 AIR QUALITY IMPACTS 1.4 SOCIOECONOMIC IMPACTS 2. PURPOSE AND NEED 3. ALTERNATIVES INCLUDING THE PROPOSED ACTION 3.1 ATMOSPHERIC EMISSIONS AND CONTROL 3.2 FLOII RELATED ALTERNATI’JES 3.2.1 Alternative Flow Apportionments 3.2.3 Demand Releases 3.3 WATER QUALITY 3.3.1 Mitigation of Water Quality Impacts 3.2.2 No Action Case Pa ge 1 1 2 3 4 5 9 9 13 13 15 16 17 17 • . . . 22 22 • . . . 25 • . . . 28 • • . . 28 30 30 33 33 37 42 42 49 53 • . • . 53 53 53 53 ndian 54 57 57 59 60 60 62 62 64 64 4. AFFECTED ENVIRONMEN-T 4.1 LOCATION 4.2 GEOLOGY AND SOILS 4.3 LAND USE 4.3.1 General 4.3.2 Land Use Surveys 4.3.3 Agricultural Activities . 4.4 HYDROLOGY 4.4.1 Surface Water 4.4.2 Ground Water 4.5 WATER QUALITY 4.5.1 Surface Water 4.5.2 Ground Water Quality 4.6 WATER USE 4.6.1 Municipal Use 4.6.2 Industrial Use 4.6.3 Agricultural Use 4.6.3.1 Montana Water Use 4.6.3.2 Water Use on the Fort Reservation 4.6.3.3 Canadian Water Use 4.7 VEGETATION AND WILDLIFE 4.8 AQUATIC BIOTA AND FISHERIES 4.9 METEOROLOGY AND AIR QUALITY 4.9.1 Meteorology 4.9.2 Existing Air Quality 4.10 SOCIAL AND ECONOMIC PROFILES . . . 4.10.1 Population Profile 4.10.2 Archaeological and Historical 4.10.3 Economic Profile 1 Peck I Sites ------- TABLE OF CONTENTS (continued) 5.2 WATER 5.2.1 5.3 WATER 5.3.1 5.3.2 Page 66 66 66 66 67 67 67 72 75 75 75 79 80 80 89 90 91 91 91 91 95 108 110 • • 117 • . . 117 121 122 • . 125 • . 126 126 • . • 127 • . 129 • . 134 134 ts 136 141 142 142 143 5. ENVIRONMENTAL CONSEQUENCES 5.1 AIR QUALITY IMPACTS 5.1.1 Air Quality Model 5.1.2 Power Plant Emissions 5.1.3 Model Input Parameters 5.1.4 Modeling Results 5.1.4.1 Sulfur Dioxide (SO2) 5.1.4.2 Oxides of Nitroaen (NOx) 5.1.4.3 Particulates 5.1.5 Impact Assessment 5.1.5.1 Sulfur Dioxide Impact 5.1.5.2 NO Impact 5.1.5.3 Particulate Impact 5.1.5.4 Fumigation Impact 5.1.5.5 Visibility Impacts... 5.1.5.6 Health Effects OUALITY IMPACTS Methodology 5.2.1.1 Flow Scenarios 5.2.1.2 Model Description 5.2.1.3 Water Uses 5.2.2 Predicted Flows 5.2.2.1 Flow Conditions at the 90 Level 5.2.2.2 Flow Conditions at the 10 Level 5.2.3 Direct Impacts 5.2.3.1 Municipal Water SuDply 5.2.3.2 Uses Dependent on Spring Runoff 5.2.3.3 Summer Flows 5.2.3.4 Winter Flows QUALITY IMPACTS Description of Quality Models Boron 5.3.2.1 Boron Impacts on Crops 5.3.2.2 Other Boron Impacts 5.3.3 Salinity and Sodicity 5.3.3.1 Salinity and Sodicity Impacts on Crops 5.3.3.2 Impact on Crops of Combined Effec of Salinity, Sodicity, and Boron 5.3.3.3 Other Salinity Impacts 5.3.4 Sulfate (SO 4 ) 5.3.5 Mitigative Measures to Reduce Impacts of Saline Irrigation Waters Percent 108 Percent ii ------- TABLE OF CONTENTS (continued) 5.3.5.1 Mitigative Practices for Salinity Control in Soils 5.3.5.2 Mitigative Irrigation Practices for Salinity Control in Return Flows 5.3.5.3 Source Control of Salinity . 5.4 SOCIOECONOMIC IMPACTS OF POWER PLANT CONSTRUCTION 5.4.1 Introduction 5.4.2 Description of the Construction Work Force 5.4.3 5.4.4 Economic Impacts from the Plant Economic Impacts fran the Construction Workers 5.4.5 Secondary Impacts 5.5 SOCIOECONOMIC IMPACTS OF APPORTIONMENT 5.5.1 Introduction 5.5.2 Future Conditions 5.5.3 Impacts on Income 5.5.4 Other Impacts 5.6 BIOLOGICAL IMPACTS 5.6.1 Impacts of Atmospheric Emissions on Terrestrial Biota 5.6.1.1 Gaseous Emissions 5.6.1.2 Particulate Emissions 5.6.2 Impacts of Atmospheric Emissions on Aquatic Biota 5.6.2.1 Acidification and Nitrogen Loading 5.6.2.2 Trace Element Contamination 5.6.3 Impacts of Water Quality Changes on Fish and tlildlife 5.6.3.1 Effects of Thermal Discharges 5.6.3.2 Effects of Dissolved Solids Increases 5.6.3.3 Effects of Dissolved Oxygen Changes Other Constituents of Flow Modifications on Fish and 5.6.3.4 Impacts Wildlife 5.6.4.1 Wildlife and Furbearers . . 5.6.&2 Fish 6. REFERENCES . . . . . . 211 7. LIST OF PREPARERS 226 Page 143 146 149 151 151 151 153 153 155 158 158 158 160 165 167 167 • • 167 • . 175 177 177 180 181 184 188 189 • . 191 191 • . 191 192 5.6.4 ii-’ ------- LIST OF FIGURES Figure 4.1-1 Location of the Poplar River Basin 4.1—2 Location of Poplar River Power Plant Site 4.2-1 Quaternary Geology of the U.S. Part of the Poplar River Basin 4.3-1 Land Use in Area I Surveyed by Duggan 4.3-2 Land Use in Area 2 Surveyed by Duggan 4.4-1 Major Sub-Basins of the Poplar River System 4.4-2 Outflow Hydrograph for the Poplar River Near Poplar, Montana, October, 1975, to September, 1976 4.4-3 Schematic of Typical Reach of the Poplar River 4.4-4 Ground Water Flow Regime in Canadian Part of Poplar River Basin 4.4-5 General Ground Water Flow Regime in U.S. Part of Poplar River Basin 4.5-1 Location of Water Quality Sampling Stations 4.5-2 Ranges of Selected Chemical Parameters in Water Samples From the Fort Union Formation and Fox Hills-Hells Creek Formation in U.S. Part of the Poplar River Basin 4.5-3 Ranges of Selected Chemical Parameters in Water Samples From Quaternary Alluvium, Glacial Outwash and Flaxville Formation in the U.S. Part of the the Poplar River Basin 4.6—1 Historical Water Use in the U.S. Part of the Poplar River Basin 4.6-2 Historical Water Use on the Fort Peck Indian Reservation 4.9-1 Normal Monthly Precipitation at Scobey, Montana 4.10-1 Location of Historic Sites in the Poplar River Basin and Adjacent Areas 5.1-i Spatial Distribution of the Highest 1-Hour SO 2 Concentrations (pg/rn 3 ) Obtained From the CRSTER Model for 1964, Assuming a 600 MW (1200 MW) Poplar River Power Plant with Zero Percent Emission Control 5.1-2 Spatial Distribution of the Highest 3-Hour 502 Concentrations (pg/m 3 ) Obtained From the CRSTER Model for 1964, Assuming a 600 MW (1200 NW) Poplar River Power Plant with Zero Percent Emission Control 5.1-3 Spatial Distribution of the Highest 24-Hour SO 2 Concentrations ( ig/m 3 ) Obtained From the CRSTER Model for 1964, Assuming a 600 MW (1200 MW) Poplar River Power Plant with Zero Percent Emission Control . Pa g 23 24 26 31 32 36 39 40 41 43 44 50 51 55 56 6 1 65 68 69 70 iv ------- LIST OF FIGURES (continued) Fiqure Page 5.1-4 Spatial Distribution of the 1964 Annual S02 Concentrations (ug/m 3 ) Obtained From the CRSTER Model , Assuming a 600 MW (1200 MW) Poplar River Power Plant with Zero Percent Emission Control 5.1-5 Spatial Distribution of the Highest 1-Hour NO Concentrations (ug/m 3 ) Obtained From the CRSTER Model for 1964, Assuming a 600 MW (1200 MW) Poplar River Power Plant 5.1-6 Spatial Distribution of the 1964 Annual NO Concentrations (3Jq/m 3 ) Obtained From the CRSTER Model , Assuming a 600 MW (1200 MW) Poplar River Power Plant 5.1-7 Spatial Distribution of the Highest 2d-Hour Particulate Concentrations ( ig/m 3 ) Obtained From the CRSTER Model for 1964, Assuming a 600 MW (1200 MW) Poplar River Power Plant with 99.5 Percent Emission Control 5.1-3 Spatial Distribution of the 1964 Annual Particulate Concentrations (iig/m 3 ) Obtained From the CRSTER Model, Assuming a 600 MW (1200 MW) Poplar River Power Plant with 99.5 Percent Emission Control 5.2-1 Location of Stations with Flow Results 5.2-2 Canadian Water Uses on the East Fork 5.2-3 Canadian Water Uses on the Middle Fork 5.2-4 Canadian Water Uses on the West Fork 5.2-5 U.S. Water Uses on the East Fork of the Poplar River 5.2-6 U.S. Water Uses on the Middle Fork of the Poplar River Above the Confluence with East Fork . 5.2-7 U.S. Water Uses on West Fork of the Poplar River (Includes Indian and non-Indian Uses) 5.2-8 U.S. Water Uses on Main Stem of Poplar River Above Fork Peck Indian Reservation 5.2-9 U.S. Water Uses on Main Stem of Poplar River Within Fork Peck Indian Reservation 5.2-10 Flows at East Fork of Poplar River at International Border 5.2-11 Flows at East Fork of Poplar River at Scobey 5.2-12 Flows at Middle Fork of Poplar River at International Border 5.2-13 Flows of Main Poplar River at Fort Peck Indian Reservation 5.2-14 Flows of West Poplar at the International Border 5.2-15 Flows of Poplar River at Poplar 5.2-16 Flows at East Fork at International Border . 5.2-17 March Flows on the East Fork 1933-1974 5.2-13 April Flows on the East Fork 1933-1974 • . 71 73 74 • 76 • 77 92 96 • 97 • 98 101 102 103 194 105 109 111 • . 112 113 114 • . 115 116 118 119 V ------- LIST OF FIGURES (continued) Fiqure Page 5.3-1 Boron Concentrations in July on East Fork and Main Stem of Poplar River for Scenarios 28, 29, 31, and 32 128 5.3-2 Boron Concentrations in July on East Fork and Main Stem of Poplar River for Scenarios 4A and 8A . . . 130 5.a-1 Estimated Construction Work Force Profile, Saskatchewan Power Plant Unit 1, 1975 through 1980 152 5.6-1 Dose-Injury Curves for (a) S0 2 -Sensitive Plant Species, (b) Plant Species of Intermediate SO 2 Sensitivity, and (c) S02-Resistant Plant Species . . . 170 5.6-2 River Heat Release Summary 185 5.6-3 Sediment Flux Versus Flow at the International Boundary East Fork Poplar River 198 5.6-4 Relationship Between Flow and Year-Class Formation of Game Fish in the East and Middle Forks of the Poplar River 205 vi ------- LIST OF TABLES Table Page 3.1-1 Maximum S02 Concentrations in the U.S. Expressed as a Percentage of the Maximum Allowable Increase (PSD) in Class II Areas 10 3.1-2 A Comparison of Class I P 50 Values and Maximum Predicted S02 Concentrations (pg/rn 3 ) 30 Miles Southeast of Plant 12 3.2-1 Description of Apportionment Alternatives 14 3.3-1 Projected Boron Concentrations (mg/i) at Station 1 . . 18 3.3-2 Projected Sodium Absorption Ratios at Station 1 . . . 19 3.3-3 Projected TDS Concentrations (mg/i) at Station 1 . . . 20 4.3-1 Land Use Characteristics of the U.S. Poplar River Drainage in 1967 (Daniels, Roosevelt and Sheridan Counties) Expressed in Acres and as the Percent of the Total Area 29 4.3-2 Livestock Inventory for Daniels County 34 4.3-3 Acres in Irrigated and Non-Irrigated Crops in Daniels County, 1975 34 4.3-4 Crop Production, Roosevelt County, 1975 35 4.3-5 Livestock Inventory, Roosevelt County 35 4.4-1 Perennial Stream Length and Drainage Basin Areas for the Poplar River Basin 38 4.4-2 Comparison of Expected Annual Flows, Mean Flows and the 1975 Flows in the Poplar River 38 4.5-1 Water Quality Statistics for Stream Sampling in Locations in Canada 45 4.5-2 U.S. EPA Water Quality Criteria Contraventions on the Poplar River, 1975 48 4.6-1 Estimates of Existing Water Use for Gravity/Pump Irrigation in the U.S. Poplar River Basin 58 4.10-1 Population in Daniels and Roosevelt Counties, 1970-1975, and Percentage Chanqe, 1970-1975 63 5.1-1 Projected Maxima Pollutant Concentrations (pg/rn 3 ) in United States Impact Area Compared with Applicable Standards 78 5.1-2 Calculated Increases in Air Concentrations of Trace Elements Near the Poplar River Plant 81 5.1-3 1975 Background Trace Element Concentrations (pg/rn 3 ) Measured Near Glasgow, Montana 82 5.1-4 Estimates of Maximum Ground-Level Concentrations (pg/rn 3 ) Durinci Morning Fumigation 84 5.1-5 Estimates of Maximum Ground-Level SO 2 Concentrations (pg/rn 3 ) During Morning Fumigation Resulting From Typical Meteorological Conditions at Scobey, Montana 85 5.1-6 Estimates of l 1aximum Ground-Level NOx Concentrations (pg/rn 3 ) During Morning Fumigation Resulting From Typical Meteorological Conditions at Scobey, Montana 86 vii ------- LIST OF TABLES (continued) Table Page 5.1-7 Estimates of Maximum Ground-Level Total Suspended Particulate (TSP) Concentrations (iig/m 3 ) During Morning Fumigation Resulting From Typical Meteorological Conditions at Scobey, Montana 87 5.1-8 Average Meteorological Conditions (100-200 M Layer) and Plume Heights During the Morning for the Mid-Seasonal Months at Scobey, Montana 88 5.1-9 Expected Health Effects of Air Pollution on Selected Population Groups 5.2-1 Reservoir Releases on the East Fork on the Poplar River 5.2-2 Summary of Flow Scenarios 94 5.3—1 Irrigation Requirements and Dilution Factors for Alfalfa and Small Grains 133 5.3—2 Salinity, SAR, and 504 Concentrations at Selected Stations 135 5.3-3 Available Studies on Salinity and Sodicity Hazards . . 137 5.3-4 Average Chemical Data for Upper Basin Soils and Soils Within Ft. Peck 140 5.3-5 Relative Tolerances of Various Crops and Forage Species to Salinity Arranged According to Decreasing Tolerances Within Groups; Modified From Allison (1964) and From Hem (1970) 145 5.4-1 Total Personal Farm and Nonfarm Income, Daniels and Roosevelt Counties 1972-1977 154 5.4-2 Total Retail Sales Daniels and Roosevelt Counties, 1973-1977 156 5.5-1 Projected Population and Employment, Daniels and Roosevelt Counties -- 1980, 1985 and 2000 159 5.5-2 Change in Farm Income Resulting From Apportionment Only 163 5.5-3 Change in Yield and Per-Acre Revenues for Wheat . . . 162 5 .5-4 Impacts of Apportionment on Personal Income in Daniels and Roosevelt Counties 164 5.5-5 Maximum Possible Impacts on Farm Income 165 5.6-1 Reported Threshold Limits of Important Native Plant and Cultivated Species Found in the Impact Area to Gaseous (SO 2 , Ox and SO 2 ÷ NOx) Emission Exposures. . 168 5.6-2 Projected Deposition Rates, Soil Concentrations and Plant Accumulation of 17 Trace Elements Resulting From Particulate Emissions 178 5.6-3 Minimum and Maximum Concentration of Trace Elements in Poplar River Basin Vegetation (‘jg/g) Samples Collected During the Late Summer of 1977 179 5.6-4 Trace Element Concentrations (PPM) in Poplar River Coal Ash Samples 182 5.6-5 Average Trace Element Concentrations ( ig/z) in the Poplar River and Projected Increases due to Atmospheric Emissions of the Poplar River Power Plant 183 viii ------- LIST OF TABLES (continued) Table Page 5.6-6 Bed Material Size Distribution 195 5.6-7 Comparison of 1977 and 1978 Spring Flows (cfs) at Selected Poplar River Stations 202 5.6-8 Predicted Average April Flows (cfs) in the East Fork Poplar River 203 5.6-9 Predicted Impact of Flow Apportionment on Young-of- the-Year Class Strength of Poplar River Game Fish . . 206 5.6-10 Recommended Instream Flows for the East Fork of the Poplar River 209 lx ------- 1. SUMMARY A coal-fired power plant is currently being constructed by Saskatche- wan Power Corporation on the East Fork of the Poplar River about 4 miles north of the International Boundary. Since the power plant and associated cooling water reservoir will result in a consumptive water use and will modify the natural transboundary flow of the Poplar River, it is antici- pated that a flow apportionment agreement between the U.S. and Canada will be established. This Environmental Impact Statement has been prepared to address the impacts of several flow apportionment alternatives in addition to other potential impacts of the power plant on the U.S. part of the Poplar River Basin. 1.1 hATER QUANTITY IMPACTS The Poplar River is a meandering prairie stream with a mean annual flow near Poplar, Montana of 83,860 ac-ft (115.8 cfs). About 32 percent of that flow comes from Canada. The flow has a wide seasonal and yearly variability. For example, the annual flow on the East Fork at the border has rancied between 0 and 32,000 ac-ft. The winter and summer are low flow periods with about three-fourths of the annual flow coming from snowmelt in March or April. Surface water uses in the Poplar Basin include munici- pal uses, stock reservoirs, and irrigation. The flows will be reduced under conditions of the recommended appor- tionment up to 50 percent of the natural flow on the West Fork and at least 60 percent of the natural flow on the Middle Fork. Flows on the East Fork will be made up of a continuous release from the Cookson Reser- voir of 1 to 3 cfs. The summer flows on the East Fork will be about 35 to 65 percent less with one power plant operating and up to 80 percent less with four power plants operating. Alternative flow apportionments were considered but the 50/50 division of flow between Canada and the U.S. with the specifications above is the best from a water quantity viewpoint. The impacts of the recommended apportionment, construction of the Cookson Reservoir, and operation of one to four 300 MWe power plants are summarized for municipal, stock and irrigation uses in this section. Municipal uses at Scobey on the Lower East Fork can be met with 1975 de- mands of 350 ac-ft and 1985 demands of 400 ac-ft. The full demands in- cludinq outdoor uses in August and September in the year 2000 cannot be met although the basic domestic uses of 30 ac-ft can be met. Spreader irrigation demands in March cannot be met from the Poplar River in one year out of ten. Stock reservoirs would be filled from the smaller tributaries during the spring runoff. Sprinkler and flood irrigation demands in June in 1975 of 4,841 acres and in 1985 of 16,288 acres can be met 50 percent of the time at all the stations. Flows are not ade- quate to meet demands ten percent of the time. In 2000, the full irri- gation demands of 29,555 acres cannot be met, since only about 4,186 acres can be irrigated near Poplar instead of the projected acreage of 1 ------- 20,618. The large increases in irrigated acreage from 1975 to 1985 and 2000 are mostly due to the projected increases on the Fort Peck Indian Reservation after construction of two reservoirs. These reservoirs sub- stantially increase the water available for irrigation on the Fort Peck Indian Reservation even with the apportionment. Erregardless, the full 29,555 acres cannot be irrigated. Changes in the flow of the Poplar River due to apportionment may im- pact organisms (e.o., furbearers, waterfowl and fish) requiring specific aquatic habitats in the basin. The highest potential for impact will occur in the East Fork. The greatest adverse impact will probably be a long-term change in channel morphology resulting in a loss of spawning and overwintering habitat for game fish. Prior to the long-term impacts, however, successful game fish reproduction will most likely occur in the East Fork under mean flows with up to two units in operation. The contin- uous low-level release during the winter will increase winter survival of fish under the Ice cover. Predicted levels of macrophyte encroachment in the upper reaches of the East Fork will result in decreased duck produc- ti on. 1.2 WATER OUALITY IMPACTS Water quality in the Poplar River was simulated using Karp III and the Modified Montreal Engineering (MME) model of the Cockson Reservoir. The quality of transboundary flow was calculated on the basis of upstream water quality plus ground water seepage, irrigation return flow and run- off as well as simulated reservoir water quality. For the purposes of evaluating the impacts of the proposed action on the quality of irrigation and potable water supplies, scenarios 28 through 32, which represent projected 1975, 1985, and 2000 conditions with recom- mended flow apportionments but without ash lagoon decant were compared with historical conditions as well as 1975 conditions with the Cookson Reservoir in place. These impacts were compared with conditions under scenarios 4.A and 8A which had all the ash lagoon decant added to Cookson Reservoir. The impacts of alternative apportionment scenarios representing increased Canadian water usage were also evaluated. The impoundment of water in Cookson Reservoir has resulted in improved water quality on the East Fork at the International Border in all seasons except spring. Operation of a single 300 MWe unit will not lead to signif- icant degradation of water quality for irrigation and other purposes. Addition of more units would result in increased concentrations of lOS and boron and higher sodium adsorption ratio (SAR) values which would cause decreased crop yields. The severity of the impacts on crops will depend partly on how the ash lagoons at the power generating site are operated. Flow on the East Fork would be made up of a small cont nuous release supplemented by larger demand releases from Cockson Reservoir. The amount of the releases is based on the March to May flow of the Middle Fork at 2 ------- the International Boundary. The flow on the East Fork is the same under the alternative apportionments so the water quality on the East Fork would not improve if an alternative apportionment is implemented. The Poplar River supports populations of game fish species - walleye and northern pike. Operation of two or more units will result in TDS concentrations in April exceeding tolerance limits for successful game fish reproduction in the East Fork one out of every ten years. With four units, the TDS concentrations in the East Fork would also limit successful spawning in all years. No adverse effects of increased TDS levels on fish are projected for other parts of the basin. Changes in other constituents are also not expected to result in adverse effects on game fish populations. 1.3 AIR QUALITY IMPACTS The highest concentrations of airborne pollutants will occur south- east of the proposed power plant based on the results from the CRSTER model . The highest annual mean concentrations of S02, 1 Ox and particu— lates were 4.8, 1.6, and 0.4 g/m 3 , respectively, for a 1200 MPe plant. The predicted concentrations were less than the U.S. National P mbient Air Quality Standards and the Montana Ambient Air Quality Standards for 1-hour, 3-hour, 24-hours, and the annual mean. The maximum increases 02 concentrations predicted from 24 to 62 percent of maximum allow- able increases for Class II areas. The particulate loading in the im- pact area was only about 2 percent of maximum allowable limits. Fumigation under very stable conditions could result in SO 2 concen- trations between 2000 and 4000 pg/m 3 at a distance of 10 to 20 km down- wind of a 1200 MWe plant. If a concentration of 4000 ig/m persisted for 30 minutes, the allowable 3 hour increase of 512 pg/rn 3 for Class II areas would be exceeded. Under more typical conditions the SO 2 concentrations were estimated to be less than 1850 pg/rn 3 . The impact of fumigation events would be minimal because of the small area affected by one event and the short time period (less than 45 minutes). Moreover, the frequency of occurrence is estimated as 11.1 and 35-45 percent for the very stable and typical atmospheric conditions, respectively. The predicted SO 2 concentrations with two 300 MWe units and no SO 2 control would exceed the Class I PSO regulations at the proposed Class J area of the Fort Peck Indian Reservation but not at the Medicine Lake National Wildlife Refuge. The regulations could be met at the Fork Peck Indian Reservation with 60 percent control for two 300 MWe units and 90 percent control for four 300 1We units. Conoarison of the predicted concentrations of SO 2 , NOx and particu- lates with acute and chronic threshold limits for selected plant species indicated no detectable impacts on the terrestrial vegetation. No im- pacts were predicted due to accumulation of trace metals in soils. Thus, no impacts were predicted on any rare and endangered species. 3 ------- 1.4 SOCIOECONOMIC IMPACTS Both Roosevelt and Daniels counties have low population densities and stable populations with only small increases projected to the year 2000. The area’s economy is dominated by agriculture, with spring wheat being the most important crop. There are currently no major industries in the area; however, the development of a potash mine near Scobey is projected for the year 2000. Expenditures of Canadian workers in Daniels County have resulted in direct and secondary impacts of 5216,000 to $324,000, representing 6.3 to 9.5 percent of total retail sales. Secondary impacts of 553,000 to 579,000 were projected for Roosevelt County. The increased expendi- tures may have prevented Daniels County from experiencing the decline in retail sales that occurred in Roosevelt County between 1974 and 1975. Analysis of the secondary effects of flow apportionment resulting in reduced development of irrigated land and poorer quality irrigation water indicates that in both Daniels and Roosevelt counties the losses of personal income (due to changes in farm income and secondary impacts) amount to about 1 percent in the year 2000. In 1985, the projected per- sonal income changes are -0.7 percent and +0.3 percent for Daniels and Roosevelt counties, respectively. Such changes are far less than his- torical variations resulting from annual weather variations. The 1985 apportionment levels result in maximum reductions of farm proprietors’ income of 1.5 percent and less than 3.1 percent for Daniels and Roosevelt counties, respectively. These respective impacts increase to 2.2 percent and 6 percent at the year 2000 level of development. 4 ------- 2. PURPOSE AND NEED In 1972, Saskatchewan Power Corporation (SPC) submitted an appli- cation to the Saskatchewan Government for water rights on the Poplar River, a basin which crosses the International Boundary in Eastern Montana. Following the issuance of water rights in 1974, SPC formally proposed the construction of a steam electric generating station on the East Fork of the Poplar River, about four miles north of the Interna- tional Boundary. The generating complex was also designed to include a reservoir on the East Fork to be used as a once-through cooling water source and a lignite coal mine near the site. On 29 April 1975, SPC was authorized by the Canadian Government to construct the power plant works, including darn and reservoir, subject to compliance with future water apportionment agreements between the U.S. and Canada. The Poplar River Basin falls within the geographical boundaries (Eastern Montana and North Dakota) of the Souris Red River Basin and under the jurisdiction of the International Joint Commission (IJC). The IJC was established in 1948 by the governments of the U.S. anc Canada to investigate and report on water requirements arising from projects on river basins comon to both countries. In responding to the planned Canadian development on the East Fork of the Poplar River, the IJC requested, on 8 April 1975, its Interna- tional Souris-Red Rivers Engineering Board to conduct a study of flow apportionment in the Poplar River Basin. The Board then appointed the Poplar River Task Force to carry out the apportionment studies. The Task Forces’ recommendatio is for flow apportionment in the Poplar River Basin were endorsed by the IJC and were published in a 1978 report entitled, “Water Appertionment in the Poplar River Basin.” The recommended apportionment essentially involves an equal division of transboundary flows between the U.S. and Canada. The following is a direct transcript of the Board’s recommended apportionment which will subsequently be referred to as Apportionment VI in this document. The aggregate natural flow of all streams and tributaries in the Poplar River Basin crossing the International Boundary shall be divided equally between Canada and the United States subject to the following conditions: 1. The total natural flow of the West Fork Poplar River and all its tributaries crossing the International Boundary shall be divided equally between Canada and the United States but the flow at the International Boundary in each tributary shall not be depleted by more than 60 percent of its natural flow. 2. The total natural flow of all remaining streams and tributaries in the Poplar River Basin crossing the International Boundary shall be divided equally 5 ------- between Canada and the United States. Specific conditions of this division are as follows: a) Canada shall deliver to the United States a minimum of 60 percent of the natural flow of the Middle Fork Poplar River at the International Boundary, as determined below the confluence of Goose Creek and Middle Fork. b) The delivery of water from Canada to the United States on the East Poplar River shall be determined on or about the first day of June of each year as follows: i) When the total natural flow of the Middle Fork Poplar River, as determined below the confluence of Goose Creek, during the immediately preceding March 1st to May 31st period does not exceed 4690 cubic decameters (3800 acre-feet), then a continuous minimum flow of 0.028 cubic meters per second (1.0 cubic feet per second) shall be delivered to the United States on the East Poplar River at the International Boundary throughout the succeeding 12 month period commencing June 1st. In addition a volume of 370 cubic decameters (300 acre-feet) shall be delivered to the United States upon de- mand at any time during the 12 month period commencing June 1st. ii) When the total natural flow of the Middle Fork Poplar River, as determined below the confluence of Goose Creek, during the imediately preceding March 1st to May 31st period is greater than 4690 cubic decameters (3800 acre-feet), but does not exceed 9250 cubic decameters (7500 acre- feet) then a continuous minimum flow of 0.057 cubic meters per second (2.0 cubic feet per second) shall be delivered to the United States on the East Poplar River at the International Boundary dur- ing the succeeding period June 1st through August 31st. A minimum delivery of 0.028 cubic meters per second (1.0 cubic feet per second) shall then be maintained from September 1st through to May 31st of the following year. In addition, a volume of 617 cubic decameters (500 acre-feet) shall 6 ------- be delivered to the United States upon demand at any time during the 12 month period commencing June 1st. iii) When the total natural flow of the Middle Fork Poplar River, as determined below the confluence of Goose Creek, during the immediately preceding March 1st to May 31st period is greater than 9250 cubic decameters (7500 acre-feet), but does not exceed 14,800 cubic decameters (12,000 acre-feet), then a continuous minimum flow of 0.085 cubic meters per second (3.0 cubic feet per second) shall be delivered to the United States on the East Poplar River at the International Boundary during the succeeding period June 1st through August 31st. A minimum delivery of 0.057 cubic meters per sec- ond (2.0 cubic feet per second) shall then be maintained from September 1st through to May 31st of the following year. In addition, a volume of 617 cubic decameters (500 acre-feet) shall be delivered to the United States upon demand at any time during the 12 month period commencing June 1st. iv) When the total natural flow of the Middle Fork Poplar, as determined below the con- fluence of Goose Creek, during the immedi- ately preceding March 1st to May 31st period exceeds 14,800 cubic decameters (12,000 acre-feet) then a continuous mini- mum flow of 0.085 cubic meters per second (3.0 cubic feet per second) shall be delivered to the United States on the East Poplar River at the International Boundary during the succeeding period June 1st through August 31st. A minimum delivery of 0.057 cubic meters per second (2.0 cubic feet per second) shall then be main- tained from September 1st through to May 31st of the following year. In addition, a volume of 1,230 cubic decameters (1,000 acre-feet) shall be delivered to the United States upon demand at any time during the 12 month period commencing June 1st. 7 ------- c) The natural flow at the International Boundary in each of the remaining individual tributaries shall not be depleted by more than 60 percent of its natural flow. 3. The natural flow and division periods for apportion- ment purposes shall be determined, unless otherwise specified, for periods of time commensurate with the uses and requirements of both countries. The IJC also authorized study of the water quality impacts of the power plant to be done by the Poplar River Task Force. The results were published by the IJC in 1979 in a report titled “International Poplar River Water Oual I ty Study’ 1 . The IJC held publ i c hearings on this report at Scobey, Montana and Coronach, Saskatchewan in September, 1979. The IJC will review the Board report and hearings and will make recommenda- tions to the Canadian desk at the U.S. State Department and the Canadian Department of External Affairs. The U.S. EPA has a liaison person work- ing with the State Department and the IJC. A water quality monitoring program is being developed by the State of Montana and the U.S. State Department. Since the SPC power plant is being constructed outside of the U.S. boundaries, there is no direct obligation for the preparation of an Environmental Impact Statement (EIS). However, a federal action is required for the U.S. Government to enter into a flow apportionment agreement with Canada. Therefore, an EIS is required prior to such an agreement which investigates all types of impacts not just flow or water quality related impacts. This environmental statement has been prepared to analyze the integrated impacts of power plant operation and flow apportionment on the Poplar River Basin and associated areas within the U.S. It is designed to meet NEPA requirements associated with the final acceptance of a flow apportionment agreement between the governments of the U.S. and Canada. 8 ------- 3. ALTERNATiVES INCLUDING THE PROPOSED ACTION 3.1 ATMOSPHERIC EMISSIONS AND CONTROL Current plans for the SPC Power Plant include operation with 0 per- cent 502 control (i.e., no flue gas desulfurization equipment). The plant is also expected to operate at a particulate control rate of 99.5 percent by the use of electrostatic precipitators. The impact analyses presented in Section 5.1 indicate that there will be no violations of ambient state or Federal air quality standards if the plant is operated with up to four 300 MWe units with no SO 2 controls. The highest predicted S02 concentrations will occur during atmospheric inversions which result in emission plume fumigations. Although speci- fied levels of S02 concentrations may be exceeded during fumigation events, it is improbable that these events will be of sufficient fre- quency to violate Montana’s 1-hour SO 2 standard. Tne highest mean annual increases above background SO2 concentrations are predicted by the CRSTER model to occur along the 120° to 1700 azimuths (generally southeast) from the plant site; predicted S02 concentrations, even at locations near the International Boundary, are well below standards. Moreover, the pre- dicted maximum concentrations and duration of exposures are also below acute and chronic threshold limits for the most sensitive plant species. Therefore, although the SPC power plant will result in elevated concen- trations of atmospheric constituents (SO 2 , NOx and particulates), there are rio projected impacts on terrestrial ecosystems or human health in the area. Although no air quality impacts are predicted with 0 percent SO 2 control, the effects of flue gas desulfurization (FGD) are also consid- ered. Current FGD systems are capable of SO 2 control ranging from about 60 to over 90 percent reduction. Therefore, the alternatives of 60 and 90 percent SO 2 control were considered. Table 3.1-1 illustrates the effocts of S02 stack controls and number of operating units on ambient S02 concentrations. When the maximum allowable increases for Class II areas are compared with predicted increases resulting from the Poplar River Plant, the maximum values with four operating units and 0 percent S02 control represent only about 37.5 percent and 24.0 percent of the 3-hour and annual allowable values, respectively. A similar comparison may be made for particulate emissions. At a 99 percent level of ESP control , the maximum values are only 14.0 per- cent and 2.1 percent of the maximum allowable (PSD) 24-hour and annual increases, respectively. These percentages would be reduced to 7 and 1 percent with the use of 99.5 percent ESP’s (as planned). It should be emphasized that the preceding discussion has considered the maximum con- stituent concentrations occurring near the International Boundary. The predicted maximum concentrations occurring in most of the U.S. part of the Poplar River Basin are much less than those near the boundary. For example, maximum 507 concentrations predicted for most of Daniels County 9 ------- Table 3.1—1 MAXIMUM CONCENTRATIONS IN THE U.S. EXPRESSED AS A PERCENTAGE OF THE MAXIMUM ALLOWABLE INCREASE (PSD) IN CLASS II AREAS Level of Control Number of Units Two 3-hour Four 18.7 37.5 O percent 60 percent 90 percent annual 12.0 24.0 3-hour 7.5 15.0 annual 4.8 9.6 3-hour 1.9 3.8 annual 1.2 2.4 10 ------- are about an order of magnitude (ten times) less than those occurring near the border. Therefore, the relationship of predicted ambient con- centrations to maximum allowable increases is considerably more diver- aent -in most of Daniels County than is indicated by the preceding com- parisons at locations near the border. The potential for morning fumigation events is quite high in the Poplar River Basin and the predicted ground-level concentrations of SO 2 are about equal to the acute threshold limits for sensitive species. Although no adverse impacts on terrestrial vegetation due to fumigation are predicted due to the short duration and isolated spatial occurrences, the projected SO 2 concentrations during fumigation would be reduced to below acute threshold limits with the addition of FGD. The Medicine Lake National Wildlife Refuge is a class I area located approximately 65 miles downwind from the power plant site. This distance is beyond the reliable predictive limits of the CRSTER model; however, the potential impacts of atmospheric emissions must be considered due to the very limited concentration increases allowed based on PSD regulations (1977 Clean Air Act). Additionally, the Fort Peck Indian Reservation represents an area which is now being considered for class I designation. The northern boundary of this area is directly south of the power plant site at a distance of approximately 30 miles. With 99.5 percent control (1200 MW, four units), the particulate concentrations at a downwind distance of 30 miles (the limit of model- ing results) are about 0.8 and 0.08 ug/m 3 for the maximum 24-hour and annual mean concentrations, respectively. These values are well be- low the PSD values of 5 and 10 pg/ma for the corresponding exposure times. With 99 percent control the predicted concentration at 30 miles downwind would still be only twice the 99.5 percent values, and would therefore remain well below the class I PSD values. Moreover, dispersion effects in the next 35 miles to the refuge would result In considerable further reduction in the particulate concentrations. The predicted maximum SO 2 concentrations for two power plant units (zero percent control) at the modeled distance limits (30 miles) equal or exceed the class I PSD regulations for 24-hour and 3-hour averages (Table 3.1-2). t Ihile these levels would result in violations within the proposed class I area, the values presented are for areas located about 35 miles from the class I wildlife refuge. Extrapolation of the modeled diffusion rate indicates that ambient increases in SO 2 concentrations at the refuge would be well below PSD regulation values. As indicated in Table 3.1-2, the use of 60 percent or higher SO 2 control on a two-unit plant would result in increased concentrations less than class I PSD values at a distance of 30 miles. Therefore, with the FGD systems, a 600 MW plant would have an extremely low probability of PSD contravention at the refuge. 11 ------- Table 3.1-2 A COMPARISON OF CLASS I PSD VALUES AND MAXIMUM PREDICTED SO 2 CONCENTRATIONS (pG/M 3 ) 30 MILES SOUTHEAST OF PLANT Maximum S07 Concentrations Class I PSD Regulations Two Unit Four Unit ( ‘ ig/m 3 ) 0* (__60* 90* 0* 60* 90* Annual 2 1 0.4 0.1 2 0.8 0.2 24-hour 5 10 4 1 20 8 2 3-hour 25 25 10 2 50 20 5 *Percent of SO 2 Control The operation of a 1200 MW plant without EGO would result in pre- dicted maximal 24-hour SO 2 concentration increases of about 20 ig/m 3 at a distance of 30 miles (Table 3.1-2). Such increases above ambient levels are about four times the class I PSD values, and, based on the approximate predicted diffusion rate for 24-hour concentrations beyond the 30-mile modeling distance, they would remain slightly above the PSD values (7.1 ug/m 3 ) at the 65-mile distance to the refuge. Using the same approach for annual or 3-hour values would result in predicted con- centrations below the allowable limits. Operation of four 300 MW units with at least 60 percent EGO systems would result in predicted concen- trations below the maximum allowable increases at the Medicine Lake Refuge. Although the previous approximate calculations result in a potential for a 24-hour S02 violation (with four units and zero percent control) of the PSD regulations for the Medicine Lake Wildlife Refuge, the actual probability for such an occurrence is extremely low due to the nature of the modeling methodology. The predictive value of a Gaussian Plume model such as CRSTER is quite low at distances beyond 25 to 30 miles from the source. The resultant concentrations at the distance limits of the model should be considered very conservative (i.e., they are probably much higher than the actual concentrations under normal meteorological condi- tions). This is especially true under stable conditions. The conservative nature of the predicted SO 2 concentrations is further enhanced when the limits are extended to 65 miles. The CRSTER modeling results indicate a possibility of contravention of class I PSD regulations in the northern portion of the Fort Peck Indian Reservation, which is a potential class I area. As indicated in Table 3.1-2 the operation of four units with 60 percent control would result in the violation of the 24-hour standard at a distance of 30 miles from the power plant. All the class I standards could be met if the SO 2 control was increased to 90 percent. 12 ------- 3.2 FLOW RELATED ALTERNATI’/ES 3.2.1 Alternative Flow Apportionments Four alternative apportionments were considered by the Poplar River Task Force. Three of the alternatives assume an equal division of the total natural flow of the Poplar River. One alternative is a division of flow such that Canada would be entitled to 70 percent of the flow and the U.S. 30 percent. The alternatives are summarized in Table 3.2-1. The no-action case, i.e., no apportionment, would allow Canada to use all of the flow within the Canadian part of the basin for the worst case. The scenarios (4 to 6) were run with 1975, 1985, and 2000 levels of development in the U.S. The model scenarios did not include the Cookson Reservoir or power plants. Another scenario (3) could be con- sidered a no-action case in that it included the Cookson Reservoir but no power plants and 1975 levels of development. The June flcws at the Lower West and Middle forks at a 10 percent frequency are the same for all the alternative apportionments (see Appendix Table F-2). Flows occurring at a 50 percent frequency in 1975 are lowest for Apportionment V and highest for Apportionment IVa and VI. In 2000 with four power plants the flows are 8.1 ac-ft higher under Apportionment V. Flows occurring at a 90 percent frequency are 24.3 ac- ft higher under Apportionment IVa in 1975 and 2000. Water demands cannot be met with water available 9 out of 10 years at station 7 under any of the apportionments in 1975 or 2000 and at station 11 in 2000. Water demands could not be met 50 percent of the time in 2000 at station 7 under Apportionment V. Thus, although slightly more water is available in June under Apportionment IVa, it is not enough to meet demands. Comparing flows under apportionments IVa and VI for July, August, and September at stations 7 and 11 shows that flows are zero 9 out of 10 years for these months. Water available 50 percent of the time is zero at station 7 for both apportionments and zero in July and September at station 11. Flows in August are 8.1 ac-ft higher at station 11 under Apportionment IVa at the 50 percent frequency, but 57 ac-ft less in March under Apportionment IVa. At the 90 percent frequency the flows are 8 ac-ft higher in July at station 7, but 16.2 ac-ft lower at station 11 under Apportionment IVa. This same pattern is also true for March flows. The March flows are critical for fish and wildlife and for spreader irrigation. The Middle Fork has better fish habitat than the West Fork, but less spreader irrigation. Demands for spreader irrigation in March can be met at both the Middle and West Forks under both apportionments IVa and ‘11 through 2000. Summer irrigation demands are exceeded for the same months and frequencies for both apportionments. Overall , 40 ac-ft more water would be available 50 percent of the time under Apportionment VI and IVa for these months. Eight ac-ft more water would be available 10 percent of the time under Apportionment VI. 13 ------- Table 3.2-1 DESCRIPTIONS OF APPORTIONMENT ALTERNATIVES Percent of Flow to United States —— Model Apportionment West Fork Middle Fork East Fork Other Trib. Scenarios II 50 percent division no restrictions -- lIla 40-60 60 30-50 40 1O_ 12* IIIb 60 40-60 30-50 40 7_9* IVa 40-60 60 Releases** 100 18-22 IVb 60 40-60 Releases 100 13-17 V 30 30 Releases 100 23-27 VI 50 60 Releases 60 28-32 *These scenarios did not include Cookson Reservoir or power plants, so will not be discussed. *AThe volumes of releases are at least 1 cfs. The specific releases are listed in Table 5.2-2. ------- Apportionment IVb would provide at least 60 percent of the natu- ral flow of the West Fork, but only 40 percent of the natural flow of the Middle Fork. Flow at the Lower Middle Fork (station 7) would be slightly less than scenarios 28 to 32, and demands could not be met from June to September for the same percentage of time as for scenar- ios 28 to 32. Flows in the West Fork would be higher, but demands still cannot be met for the same percentages of time from May through September. Thus, none of the flow apportionment alternatives allow full water demands to be met. Apportionment VI appears best from a water quantity viewpoint, although the increased March flows in the Lower Middle Fork under ha would be beneficial to fish and wildlife. 3.2.2 No Action Case The no-action case under existing 1975 conditions with the Cook— son Reservoir and the worst case under 1975, 1985, and 2000 levels of development are compared to historical flows (scenario 2). Flows are compared for March which is important for stock, fish and wildlife, and spreader irrigation and June through September which is the main irrigation season. Flows under existing conditions for the Middle and West Forks (stations 4, 7, 9 and 11) are the same for scenarios 2 and 3. Flows on the East Fork at the border are higher at low flows for scenario 3 due to seepage from the reservoir. The median flows in March are about 85 percent less under scenario 3 than scenario 2. Summer median flows for scenario 3 vary from 19 percent less in September to 20 per- cent more in July. March high flows are about 46 percent less under scenario 3. Summer high flows were 35 percent less in June to 39 per- cent more in August. Low flows at Scobey (station 3) are zero in March for both scenarios 2 and 3. Summer flows at station 3 were 2 to 240 percent higher under scenario 3 at low flow conditions because of the continuous seepage from the reservoir. Median flows were 7 to 13 percent less and high flows were 38 to 30 percent less in June and September due to the increased water uses of 1975. July and August flows are 75 to 240 percent higher under low flow conditions and 38 percent higher under median conditions due to delayed irrigation re- turn flows. The high flows were 7 percent less in July and 23 percent higher in August. The low flows under existing conditions are adequate to meet municipal, stock, and irrigation demands at Scobey (station 3). Irri- gation and stock demands can be met on the Middle Fork only in March, April, and May. Stock and irrigation demands can be met on the West Fork for all months except August and September. Stock and irrigation demands on the main Poplar (station 8) cannot be met in March or June through September. Demands on the Lower Main Poplar (station 12) can- not be met in March, July or August. Under high flow conditions de- mands can be met at all staticns except the Middle Fork (station 7) in August and September. 15 ------- Flows for the worst case (scenarios 4 to 6) at the border stations of the three forks are zero during the summer and for the low to median flows in March (see Appendix Table F-5). March low flows are the same as historical conditions in 1975 for all but station 7 and are only 2 percent less there. Under 2000 levels of development the flows are zero at station 3 and 47 percent less at station 11. Median and high flows are significantly less but water demands can be met at stations 3, 7, and 11 through the year 2000. Demands at station 8 could be met only with high flows. Demands at station 12 could be met in 1975 and 1985 with the high flows only, although water t.,iould be available from the Poplar reservoirs. Low flows in the summer are about the same at all stations except 3 which is zero for the worst no-action cases. Median and hiah flows in 1975 are between 25 and 50 percent less. By 1985 and 2000 the increased water demands result in zero flows most of the time for the low flow and median flow cases. The 1985 and 2000 demands can be met under high flow conditions at all stations in June and July and under 1985 demands in August and September. The months when demands cannot be met are the same as for scenario 3, but fewer acres could be irriaated because of the decreased amount of water. 3.2.3 Demand Releases The actual impact of the flow apportionments will depend partly on the timing and flow rate (cfs) of the one-time releases. The schedule used in the model spread the release over the period from May to Septem- ber as recommended by the Poplar River Task Force: Month Percent May 12 June 18 July 32 August 27 September 11 This division was based on need for irrigation rather than the timing of a specific method of irrigation. However, the average number of irriga- tion applications in the Poplar Basin was 2.4 with a maximum of 4. One approach to increase the water available for irrigation would be to drop the release in May and increase the releases in July through September when more water is needed. Another consideration is the flow rate - a higher flow rate for a period corresponding to the length of the normal irrigation application would be beneficial. 16 ------- Another approach would be to use the September release amount to miticiate the impact of the apportionment on fish and wildlife. The re- lease could then be made in April of 33 ac-ft. If the release was made in one day the flow rate would be 16.6 cfs and if in two days the flow rate would be 8.3 cfs. These flow rates are not adequate for maintain- ing channel morphology but would be a significant addition to the appor- tionment flows on the East Fork and would increase the flow rate to the recommended flow of 10 cfs. 3.3 WATER QUALITY Evaluation of alternative transboundary flows, i.e., 70/30 apportion- ment (V), indicates that the operation of one to four 300 MW units at successive levels of development will have the same effect on water quality at station 1 as the identical sequence of development at the recommended apportionments (scenarios 28 to 32). The predicted boron, 1DS and SAR levels at station 1 provided by the water quality simulation model for scenarios 23 to 27 are shown in Tables 3.3-1 to 3.3-3. These values at the 90 and 50 percent probability levels are identical to those predicted for scenarios 28 to 32 (i.e., equal apportionment). Similar levels of boron, TDS and SAR are predicted at stations 3 and 8 under scenarios 28 through 32 and 23 through 27. Boron concentrations result- ing from scenario 32 will result in levels exceeding acceptable limlts for semi-tolerant crops 10 percent of the time. The levels of these con- stituents at stations 3 and 8 are presented in Appendix Tables H-i through H-6. Modeling scenarios 4, 5 and 6 represent the worst case action in terms of apportionment alternatives. Under these conditions Canada would make unlimited use of available water resources. These scenarios do not consider the impacts of either water storage (reservoir in place) or power plant utilization, and, therefore, represent unlikely alternatives. Based on water quality sinulations, scenarios 4, 5 and 6 would result in both the unavailability of sufficient supplies and significant deterio- ration in water quality at station 1 during the period of March through September. Although SO 4 and SAR levels would be expected to remain within acceptable limits, predicted boron and TDS levels at station 1 would be high durinci the period July through September (50% probability). Water quality would not be affected by scenarios 4, 5 and 6 at stations 3 or 8. 3.3.1 Mitigation of Water Quality Impacts The increased salinities of East Fork waters under the apportionment alternatives are due to mine and power plant related inflows, Fife Lake overflows, and evaporation in Cookson Reservoir. Modifications in the ash settling lagoons to elininate decanting to the reservoir and minimize ground ‘ iater seepage would decrease TDS concentrations in the East Fork (station 1) by about 10 percent. Boron concentrations could be reduced significantly from a maximum predicted 90 percent probability level of 9.3 to about 2.1 mg/9 .. The proposed mitigation measures by SPC include 17 ------- Table 3.3—1 PROJECTED BORON CONCENTRPTIONS (MG/2 ) AT STATION 1 Percent Month Probabi 1 i ty Scenario Level March April j June July August September j90 - - - - - - - 150 - - 2.1 2.0 3.2 4.4 3.5 190 - - - - - - - 150 - - 2.2 2.0 3.4 4.9 3.8 190 - - - - - - - 6 150 - - 2.2 2.2 4.3 5.5 4.9 9O 1.9 1.8 1.9 1.9 1.9 2.0 2.0 23 50 0.9 0.8 0.8 0.8 0.8 0.9 0.9 j9O 2.4 2.2 2.2 2.2 2.3 2.4 2.5 24 50 1.2 1.0 1.0 1.0 1.0 1.1 1.2 90 3.7 2.9 2.9 3.0 3.1 3.3 3.6 25 50 1.6 1.3 1.3 1.3 1.4 1.5 1.6 j90 3.7 2.9 2.9 3.0 3.1 3.3 3.6 26 5O 1.6 1.3 1.3 1.3 1.4 1.5 1.6 590 8.0 4.8 3.8 4.1 4.7 5.5 6.5 27 150 2.2 1.5 1.3 1.3 1.6 1.8 18 ------- Table 3.3-2 PROJECTED SODIUM ABSORPTION RATIOS AT STATION 1 Percent i Probability onth Scenario Level March April May June July August September 100 - - - - - - - 4 5O - - 3.9 3.7 5.2 6.1 5.5 (90 - - - - - - - 5 ‘50 - - 3.9 3.7 5.3 6.4 5.7 190 - - - - - - - 0 4.0 3.8 6.0 6.6 6.4 9O 17.1 14.8 13.6 12.8 12.2 12.0 11.9 23 ‘50 8.5 5.7 5.1 4.9 4.8 4.8 4.8 24 190 19.7 15.7 14.7 13.8 13.2 13.1 13.2 50 10.6 7.0 6.0 5.8 5.7 5.7 5.8 (90 22.2 17.6 16.4 15.7 15.1 15.1 15.4 25 ‘50 12.6 8.4 7.3 7.1 7.0 7.1 7.1 190 22.2 17.6 16 . 15.7 15.1 15.1 15.4 26 50 12.6 8.4 7.3 7.1 7.0 7.1 7.1 27 j90 31.2 22.9 18.9 18.6 17.7 16.6 16.4 50 12.8 8.5 6.0 6.0 6.1 6.3 6.4 19 ------- Table 3.3-3 PROJECTED TDS CONCENTRATIONS (MG/SQ) AT STATION 1 Percent Month Probability Scenario Level March April May June July August September (90 - - - - - - 4 ‘50 - 1192 1103 1635 2279 1833 190 - - - - - - 5 50 - 1207 1127 1745 2536 1960 (90 - - - - - - 6 50 - 1243 1207 2243 2853 2530 9O 984 930 935 946 958 992 1028 23 5O 583 530 507 522 547 573 596 24 1249 1107 1110 1131 115d 1208 1268 50 747 653 53 1 653 678 711 744 90 1967 1459 1462 1506 1559 1668 1793 25 50 1003 859 816 842 885 936 991 (90 1967 1459 1462 1506 1559 1668 1793 26 ‘50 1003 859 816 842 885 936 991 190 4796 2551 2381 2546 2867 3358 3978 27 ‘50 1347 999 847 884 965 1068 1146 20 ------- recirculat-jon of the ash lagoon decant to the power plant instead of discharge to the Cookson Reservoir and compaction of a 300 rr n clay layer as a base for the ash lagoons. These measures would limit total seepage to the East Fork and reservoir to less than 2 1/sec (IJC, 1979). The concentrations in the East Fork could be reduced even further if compact- ion was extended to a 600 mm layer which would limit seepane to approxi- mately 0.7 Z/sec (IJC, 1979). The resulting boron concentrations in the East Fork were estimated to be a maximum of 3.3 mg/2. if no ground water mounding occurred and a maximum of 5 mg/P. if mounding at the ash lagoon sites occurred. Other mitigation methods to reduce impacts of saline irrication waters would most likely involve methods to control salts in irrigation return water and salt buildup in soils. These methods are fully de- scribed in Section 5.3.4. A leaching fraction of 0.2 minimizes the impacts of the poor quality irrigation water on crop yields. Increasing the leaching fraction to 0.3 results in only a small improvement in yield which would probably be offset by the loss of acreage which could be irrigated with the available water. 21 ------- 4. AFFECTED ENVIR0NI 1ENT 4.1 LOCATION The Poplar River basin is located in Southern Saskatchewan (Canada) and Northeastern Montana between 49° 301 and 48° north lati- tude and 104° 45’ and 106° 45’ west longitude (Figure 4.1-1). The Poplar River originates in Saskatchewan as three main tributaries: West Fork, Middle Fork and East Fork. A major portion of the Middle and East Forks drainage basins lies in Canada. Both of these streams join to form the main stem of the Poplar River near the town of Scobey, Montana, located approximately 12 miles south of the inter- national boundary. The West Fork sub-basin is located mainly in Montana and joins the Poplar River at a point approximately 37 miles below the U.S.-Canadian boundary. The Poplar River may be divided into five major segments which will form the basis for subsequent discussions concerning apportion- ment alternatives and associated flow regimes. In addition to the three aforementioned forks, the main stem of the Poplar River may be divided into a 25—mile segment between the confluence of the East and Middle Forks and the confluence of the West Fork and a 40-mile segment between the West Fork confluence and the Missouri River. Three small transboundary tributaries originate in Canada and join the East, Middle and West Forks near the international boundary: Coal Creek, Cow Creek and the East Tributary. Other tributaries such as Butte Creek, Cottonwood Creek and Police Creek are located entirely in the U.S. part of the basin. The Poplar River Power Plant is currently being constructed at a site located approximately 4.3 miles north of the International Bound- ary (Figure 4.1-2). The site is located adjacent to a 1600-acre im- poundment (Cookson Reservoir) which will be used as a water source for the plant’s once-through cooling water system. The total storage volume of Cookson Reservoir is approximately 30,000 acre-feet. Al- though only one 300-MW coal-fired plant is currently under construc- tion, an additional unit of equal size is planned for the site. The addition of two other 300-MW units is also considered feasible if the r ecessary increased cooling water is available at the site. In addition to an adjacent surface coal mine, the following an- cillary facilities are planned: coal handling plant, water treatment facilities and wet-ash disposal system (lagoon). The lagoon location is indicated in Figure 4.1-2. 22 ------- Canada USA Oplieini - - Glentana \ . 4 0 4 8 12 6 0 6 12 18 Kiloinieters Saskatchewan -- — - Sheridan County -- - - Montana Westhy Redstone -- -“ Plentywood ‘p Northern Boundar Fork Peck l.R. - Medicine) Medicine Lake Natlondi Wildlife Refuge - Roosevelt County Froul LOCATION OF THE POPLAR RIVER BASIN N Miles La Brockton —- - - - 2 Figure 4.1-1 ------- Figure 4.1-2 LOCATION OF POPLAR RIVER POWER PLANT SITE 24 Scale 0123456 km ------- 4.2 GEOLOGY AND SOILS The Poplar River Basin is located in the Northern Great Plains. The area is characterized by flat to gently dipping sedimentary strata overlain by glacial deposits and alluvium in the river valleys. The study area is at the northern edge of the Williston Basin, a large syncline in Montana and North Dakota. The formations exposed in the area are the Bearpaw Shale,Fox Hills sandstone, and Hell Creek Formation of Cretaceous aae; the Fort Union arid Flaxville Formations of Tertiary Age, and Ouaternary gravels, alluviun, and glacial deposits. The gene- ral stratigraphic section for the region and local variations within the Poplar Basin are discussed for the formations in Appendix A-i. The Quaternary period can be divided into the Pleistocene series dominated by glacial activity and the Holocene series dominated by fluvial activity. The oldest formation which predates the glacial period is the Wiota Gravels. The location of glacial and recent deposits in the Poplar River Basin are shown in Figure 4.2-1. Gen- erally, the till deposits consist of unstratified clay, silt, sand and gravel. The average thickness is 10 feet. Other types of glacial deposits include eskers, kames, glacial outwash sediments, and lake deposits. Recent deposits include alluvium in the river valleys, colluvium in slope-wash and alluvial fans, landslide material, and sand dunes. The alluvium is composed of locally-derived sand, silt and gravel and may be up to O feet thick. Samples of the river banks analyzed by the Montana Department of Natural Resources and Conservation (1978) at nine locations along the entire Poplar River’ system were as follows: Flood—plain 85-1OO Silty Loam 5-15 Gravel Upper Bank 85-95 Silty Loam O-5 Sand 2.5-15 Gravel Lower Bank 85-95 Silt/Silty Loam 5-15 Sand arid Gravel Channel 40-85 Silt Channel 5-2O Sand 10-10OO Gravel Along the Mainstem of the Poplar River below the confluence with the West Fork and the middle of the East Fork, the lower bank and channel are 100 percent gravel . Sand dunes occur southeast of Four Buttes and northeast of the town of Poplar. The dunes consist of gray sand with a relief of 10 feet. Vegetation stabilizes most of the dunes. 25 ------- Tfg Tf J : Qewd 5” ’ •• — - Tfg V \ \\ Qal T g QaI _. - —- _: := Qsq “ - 3 - T g ) / —:‘ r -G - ’ — -‘ .‘ If r Tfg L _ \ j/ j N ) ‘ ‘ ‘ Qewd • -‘ 7 I / \ J \, Qj 1’ Qewd c / / “ ( ) Q g\\ ;//f ’ .:’\ Qd, ’\ Key afrer Howard, 1960 0 MILES 6 Qd Dune Sand Qewd Glacial Till (Early W,sconsin age) Oic Ice contact deoosits (Kames, Eskers) Tfg F!axvil le Gravel Qsg Stratified Drift Deposits (Wisconsin age) Glacial Channels Ocg Crane Creek Gr ve1 Glacial Bars Qrnc Glacial Till ( ‘ankato Drift - Wisconsin age) Moraine Topograohy Qal Alluvium - flooa plain deposits Figure 4.2-1 QUATERNARY GEOLOGY OF THE U.S. PART OF THE POPLAR RIVER BASI’J 26 ------- The Canadian portion of the Poplar River Basin has a similar geo- logic history to the U.S. part of the basin and thus has similar rock types. The general stratigraphic sequence found in the area from youngest to oldest strata is: o Alluvium o Glacial Till * Empress Group o Ravenscrag Formation o Frenchman Formation o Bearpaw Shale • Older sedimentary rocks Ouaternary deposits include the alluvium, glacial till, and the Empress Formation. Alluvial deposits occur in the floodplain of the East Fork of the Poplar River and Girard Creek. The glacial till is less than 70 feet thick. The soils in the Poplar River Basin are derived from the glacial till and out iash deposits and the locally exposed bedrock formations. The soils are predominantly a loam type. The soils in the Canadian part of the basin belong to the Brown and Chernozemic Brown groups. At least 12 different soil series are present in the U.S. part of the basin. Soils developed on the glacial till are predominantly Williams and Zahill Soil Associations. Floodplain soils are mostly Haverlon, Trembles, and Lohler soil series. Soils developed on till over bedrock in the southern part of the basin belong to the Phillips-Scohey-Thoeny Soil Associations. These soils are loam to clay loam with a lime zone at shallow depths. Detailed descriptions of the U.S. and Canadian soil types are provided in Appendix A-i. Permeability ranged from low (0.06 inches/hour) to moderate (0.6 to 2 inches/hour) at the sampled sites in the U.S. part of the basin. Low permeability soils occur in parts of the floodplain and can restrict agricultural use of these areas. In the lower Poplar River Basin exces- sively high permeability soils (2 to 20 inches/hour) are found on hilly parts of the glacial till and sand dunes. The Banks soil series is sandy ‘ iith high permeability and low water holding capacity (approxi- mately 3.8 inches in the first four feet) (Klages, 1976). Most of the irrigated lands in the Poplar River Basin have soils belonging to three soil series (Haverlon, Trembles, and Lohler). Ap- proximately 75 percent of the irrigated soils in the area belong to the Haverlon and Trembles series (Smetana, 1979). Both of these soils are loam types. The Lohler soil is a fine loam iith some montrnoril- lonite. The average ‘. iater holding capacity in the deep loam soils 27 ------- was estimated at 10 inches (USDA, 1964). Thus, the water requirement for spreader irrigation systems was estimated as 10 inches by the Poplar River Task Force. The crop requirement for gravity or pumping irriga- tion was estimated by the Task Force as five inches since the applica- tions should take place when the soil moisture is 50 percent depleted. The total water requirement due to losses by seepage and evaporation was therefore estimated as 7.7 inches (Montana DNRC, 1978). The chemical properties of the soils are an important factor in determining the suitability of the soils for agriculture. The CEC (cation exchange capacity) of soils on the Fort Peck Indian Reservation ranged between 15 and 44 meq/iOO g. The pH of soils through the U.S. part of the Poplar Basin ranged between 7.5 and 9.5 (see Table A.1-2). Analyses of major cations including boron are included in Appendix A-i. Mineral resources of the Poplar River Basin are associated with the fiat-lying sedimentary strata of Cretaceous and Tertiary Age and the glacial deposits of Quaternary Age. Detailed descriptions of the fuel and non-fuel resources are included in Appendix A-i. Fuel re- sources include oil and coal. Oil has been produced from five fields in the Poplar River Basin. Several lignite coal fields exist in the U.S. part of the Poplar River Basin, although no coal is presently being mined. The fields have a low probability for development due to overburden and low Btu value (Montana Energy Advisory Council, 1976). There are 12 coal fields in the Canadian part of the basin. The Hart coal seam will be mined for the SPC power plant at a rate of 50 million tons per 300 MWe unit over the life of the plant. Non-fuel resources include potash, quartzite, bentonite, sand, gravel, clay and marl. Potash is mined in Saskatche ian by the Pitts- burgh Plate Glass Industries. The Farmer’s Potash Company has plans for a mine and processing plant near Scobey, Montana. 4.3 LAND USE 4.3.1 General The Poplar River Basin (Daniels and Roosevelt Counties) and ad- jacent Sheridan County are rural, sparsely-populated areas in which the majority of land is devoted to agricultural use (Table 4.3-1). In Daniels and Roosevelt counties over 98 percent of the total acreage is classified as cropland, pasture or rangeland. Almost all of the crop- land is used for dryland farming. On the Fort Peck Indian Reservation the majority (68 ) of the reservation lands was used for open grazing in 1972. Only 30 percent of this land belongs to the Indians. The other major land USC iS dry land farming (29%). Sixty percent of the dry land farming is on land used by the Indians. 28 ------- Table 4.3-1 LAND USE CHARACTERISTICS OF TilE U.S. POPLAR RIVER DRAINAGE IN 1967 (DANIELS, ROOS [ VELT AND SHERiDAN COUNNES) EXPRESSED IN ACRES AND AS TILE PERCENI OF TILE FU1AL AREA County Total Area Cropland Pasture Range Forest Other Daniels 911,938 543,166 4,550 352,896 0 11,326 59.6% 0.5% 38.7% 0.0% 1.2% Roosevelt 1,501,671 731,915 20,090 722,902 8,745 18,025 48.71% 1.34% 48.14% 0.58% 1.2% Sheridan 1,047,532 638,310 32,500 368,081 0 8,641 58.7% 3.0% 33.8% 0.0% 0.8% TOTAL 3,461,147 1,913,391 57,110 1,443,879 8,745 37,992 55.3% 1.6% 41.1% .30% 1.1% Source: USDA, SCS, 1973 and 1976 ------- The majority of the land is privately owned in Daniels, Roosevelt, and Sheridan counties. Detailed tables for land ownership are given in Appendix A-2. In Daniels County the amount of federally-owned lands is relatively small (0.09%) and is comprised of about 850 acres of National Resource Lands and U.S. Fish and Uildlife Service refuge. The relative amount of federally owned lands in Roosevelt and Sheridan counties is greater and comprises 3.6 and 2.5 percent of the total areas, respec- tively. In Roosevelt County most of the federal land is owned by the Bureau of Indian Affairs (non—trust lands), while in Sheridan County almost all of the federal land is associated with the Medicine Lake National Wildlife Refuge. The total land area of Fort Peck Indian Reservation is 2,093,124 acres. However, over 50 percent of the reservation land is owned by non-Indians. All deeded land, state and county, within the reservation is included in this ownership category, as well as all federally-owned land not assigned specifically for use by Indians. The remaining land is divided into three ownership categories, Tribal Indian Trust land o’,ined by the tribe (11.3%), and individual allotted (30.2 ), and fed- eral government land assigned for use by Indians (4.1%). 4.3.2 Land Use Surveys In an effort to describe land use classifications in detail in the direct down-wind region from the plant, aerial infra-red surveys were conducted in 1978 (Duggan, 1979). The area surveyed extends about 30 miles into the U.S. The area was selected to correspond to the most prevalent wind direction (i.e., north-westerly). Therefore, these areas would have the highest potential for impact resulting from atmospheric emissions from the Poplar Plant. The land use classifica- tions for two of the surveyed areas are included as Figures 4.3-1 and 4.3-2. The proportion of cultivated land in the U.S. (Areas 1 and 2) was quite high and ranged from 70.9 to 73.9 percent. These values are higher than the countywide values of about 60 percent cropland (Table 4.3-1). There was also a corresponding decrease in the amount of rangeland when compared with the overall county figures. Wetlands comprised from 3.5 to 4.3 percent of the U.S. areas surveyed. In Area 1 the wetlands mapped were adjacent to the East Fork Poplar River and Cow Creek. In Area 2 the wetlands were directly associated with Eagle Creek and Whitetail Creek, both of which are located in the Big Muddy Creek drainage basin. 4.3.3 Agricultural Activities About 271,000 acres in Daniels County were harvested in 1975. Less than one percent of this acreage was irrigated. The number of 30 ------- w nt t .iod i C I f . on I URII) IN LIII I IVATLI) 3 RTFl( [ I Alit) 4 WIT) AT))) 5 WAILIT I - U S 0 0 73 9 At / 4 3 0 A.., I ) n )o 2 (3. 11 1 II 9 3 3 (3 il Hgure 4.3-1 LAND USE IN AR [ A 1 SUkVEY [ D DY DUGGAN (1978) ------- 0 2 M 1 o 2 3 ,J Percent Land IJ’ e llasstlir.itton I IIRBAFI 2 C l ii TIVAT(D 3 Rlktd,LLAFI 1) WLF(AUD S WAILR Area2-US 02 709 253 I OI C,-) I ”) Scale Figure 4.3-2 LAND USE TN AREA 2 SURVEYED BY DUGGAN (1978) ------- acres harvested has increased by seven percent since 1960. However, during those 15 years there was a great deal of fluctuation in acres harvested per year. For example, between 1974 and 1975, the total number of acres harvested decreased by nine percent or 26,800 acres. Cattle-, hog-, and sheep-raising also occur to some extent in the county (Table 4.3-2). The total number of farms ‘ iith sales of S2,500 and over in the county increased bet,ieen 1969 and 1974 by 19 from 435 to 454. The number of irrigated farms as a percent of total farms dropped from 3.9 percent in 1969 to 3.1 percent in 1974, even though the number of irriaated acres increased from 1,269 to 2,016. The majority of the farms (88%) are either family or individually operated. Daniels County, in spite of its small area (1,443 square miles), ranked third in spring wheat production and fourth in durum wheat production in the state in 1975. The crops produced in the study area are grown largely on nonirrigated soil. The crops are usually planted in strips, leaving unused areas between to preserve water for the acres planted Barley and oats contribute to the feed grains production within Daniels County. Others crops raised in the county include flax seed, winter wheat, and hay. Most irrigated land in the county is used for producing wild and alfalfa hay (Table 4.3-3). Roosevelt County is ranked number one statewide in the number of acres of spring wheat harvested and number three in overall wheat pro- duction. The crops are grown almost entirely on nonirrigated soil. Only a small portion of the spring wheat and oats are irrigated. Hay is tne only crop that is irrigated to any extent and then only about 30 percent of the crop, or 12,700 of the harvested acres. Other crops planted in the county include barley, oats, rye, corn, flax, safflower, and mustard (Table 4.3-4). The number of farms with sales of S2,500 and over increased from 636 in 1969 to 659 in 1974. At the same time, the number of irrigated farms as a percent of total farms dropped from 6.1 percent in 1969 to 4.7 percent in 1974, with the total number of irrigated acres declining from 6,815 acres to 4,402 acres. Approximately 675,000 acres within the county were used for graz- ing in 1977. All of the livestock inventory showed a sharp decline between 1973 and 1976. The number of sheep and lambs decreased by al- most 50 percent. Table 4.3-5 shows changes in livestock between 1974 and 1976. 4.4 HYDROLOGY 4.4.1 Surface Water The Poplar River Basin consists of four sub-basins draining a total of 3,002 square miles (Figure 4.4-1). The West, Middle, and ------- Table 4.3-2 LIVESTOCK INVENTORY FOR DANIELS COUNTY YEARS Livestock 1974 1975 1976 All cattle and calves 2 ,6OO 24,800 24,600 Milk cows and heifers that have calved 750 100 100 Beef cows and heifers that have calved 14,700 15,400 14,000 Stock sheep and lambs 5,000 4,500 5,000 Hogs and pigsk 5,400 5,900 4,800 Chickens* 2,700 2,000 1,300 *Inventory for the years 1973-1975. Source: Montana Department of Agriculture, Montana Agricultural Statistics, December, 1976. Table 1 3_3 ACRES IN IRRIGATED AND NON-IRRIGATED CROPS DANIELS COUNTY, 1975 Irrigated Non—Irrigated Percent Crop Acreage Acreage Total Acreage of Total Spring wheat * 170,000 170,000 63 Barley * 51,400 51,400 19 Durum wheat 0 16,600 16,600 6 Flaxseed 0 5,900 5,900 2 Oats * 2,900 2,900 1 Winter wheat 0 1,500 1,500 1 All hay 2,500 20,200 22,700 8 Totals 2,500 268,500 271,000 100 *Spring wheat, barley, and oats are planted and irrigated as a cover crop in rotation with alfalfa, but total acreage of irrigated small grains is less than 1 percent of the total grain production (Montana Department of Agriculture, 1931-1977). ------- Table 4.3_Li CROP PRODUCTION, ROOSEVELT COUNTY, 1975 Crop Bushels All wheat Winter wheat Spring wheat, except durum Barley Oats All hay *Tofls 8,211 ,900 1,158,700 5,954,200 1,954,200 466,100 79,000* Source: USDA and Montana Department of Agriculture, Montana Agriculture, County Statistics, ‘I. XVI, 197 and 1975. Table 4.3-5 LIVESTOCK INVENTORY, ROOSEVELT COUNTY Years Livestock 1974 1975 1976 Percent Change All cattle and calves Milk cows and heifers that have calved Beef cows and heifers that have calved Stock sheep and lambs Hogs and pigs* Chi ckens* *Inventory is for the year’s 1973-1975 Sour-ce: USDA and Montana Department of Agriculture, Montana Agricultural Statistics, V. XVI, County Statistics 1974 and 1975. 50,400 44,000 35,000 -30 200 100 100 -50 27,900 26,200 21,700 -22 4,500 2,600 1,900 -48 7,700 5,800 5,500 -29 10,600 9,200 5,800 -44 35 ------- ion-contrbuting areas — — Sub-basin boundaries Figure 4.4-1 MAJOR SUB-BASINS OF THE POPLAR RIVER SYSTEM 36 POPLAR RiVER 8ASIP & __ T T.1--- ; - -._= - -.c — ------- East Poplar ri vers all have their headwaters in southern Saskatchewan. The East and Middle forks join at approximately 48°17’ North latitude to fork the main stem of the Poplar River. These are joined by the West fork at about 48°30’ North latitude. The main stem is 455 river miles in lengtr from the International border to the confluence iith the Missouri River and drops 450 feet over that distance (L. Brown, personal communications). Estimates of perennial channel length are shown in Table Ll.4_1 with drainaae areas for the four major sub-basins. The lengths of perennial channel for the West, Middle, and East Poplar rivers were calculated based on a sinuosity/projected length ratio for the lower Poplar. Therefore, they may tend to be high because of in- creased meandering of the river as the volume/gradient ratio increases. The mean flow of the Poplar River at the basin outlet is 115.8 cfs. The mean flows are compared to 1975 flows for the river outlet and border stations in Table 4.4-2. The outflow hydrograph for the Poplar River at Poplar, Montana is shown in Figure 4.4-2. The flow in the water year shown is a one in 8.33 year event, somewhat above the ex- pected value perhaps due to the strong peak in late June and early July caused by relatively heavy precipitation during that period. The shape of the hydrociraph is typical however, showing the strong spring peak flow and low winter flow. The Poplar River Basin has mostly low gradient, meanderina alluvial streams. The alluvium through which the streams flow is two to six feet thick and is underlain by a deep glacial till. Therefore, the banks are constructed of silts and sands, while the streams have cut into the glacial till making the beds a combination of unconsoli- dated gravels, cobbles and loose sand. A schematic of a typical reach of the Poplar River is shown in Figure 4.4-3. A detailed discussion of surface water hydrology, including annual flow frequencies and sediment transport characteristics, is included in Appendix A-3. 4.4.2 Ground Water There are three major aquifers in the Canadian part of the basin - the glacial drift including the Empress Formation, the Ravenscrag For- mation, and the Frenchman Formation. Ground water is used for domestic and stock purposes. A description of the aquifers and well yields in the U.S. and Canadian parts of the basin is included in Appendix A-4.. The general ground water flow regime in the Canadian part of the Poplar River Basin is shown in Figure 4.4-4. The upper part of the basin flows into Fife Lake. In dry or normal years there is no over -- flow from Fife Lake into Girard Creek. The only loss is from evapo- ration. In wet years ther-e nay be overflows as occurred in 1952-53 and 1975-76. The ground water in the lower Girard Creek sub-basin flous southeastt.iard into the East Fork of the Poplar River. There is another loss to the basin in the East Fork sub-basin ‘ ihere the ground 37 ------- Table 4.4-1 PERENNIAL STREAM LENGTH AND DRAINAGE BASIN AREAS FOR THE POPLAR RIVER BASIN Basin Segment Length of Perennial Stream (River-miles) 0 Major rder of Drainage Area* Drained (mi 2 ) Drainage Density (mi l West Poplar 390 2 1009 .39 Middle Poplar 2â4 2 (582) .34 East Poplar 212 2 (485) .32 Poplar 341 3 926 .37 TOTAL 1187 - (3002) .36 *Numbers in parenthesis indicate drainage areas without Fife Lake non-contributing area. Table 4.4-2 COMPARISON OF EXPECTED ANNUAL FLOWS, MEAN FLOWS AND THE 1975 FLOWS IN THE POPLAR RIVER River Segment Expected Annual Flow (ac-ft) Return Period (yrs) Mean Flow* (cfs) 1975 Flow (ac-ft) West Fork @ I.B. 3,445 3.0 4.76 9,200 Middle Fork @ I.B. 11,790 2.7 16.28 34,040 East Fork @ I .B. 11,850 2.9 16.37 34,040 Poplar River @ Poplar, Montana 83,860 3.0 115.83 323,000 *Period of Record: 1933-1974. 38 ------- I I I I I I I I I I I I I I 0 N D J F M A M J J A S 1975 1976 Figure 4.4-2 OUTFLO’J H’(DROGRAPH FOR THE POPLAR RI’JER NEAR POPL, R, MONTANA, OCTOBER, 1975, TO SEPTEMBER, 1976 100000 10000 - 1000 — 100 — 10 — 0 39 ------- / b ELEVATION b-b Figure 4.4-3 SCHEMATIC OF TYPICAL REACH OF THE POPLAR RIVER / / / / / / / a a I I a’ a’ ELEVATION a—a \ BANKFULL STR EAM WIDTH Xb’ \ N N \ \ IFFLE b’ POINT BAR 7 / / / / 40 ------- 0 5 5 0 5 MILES K I LOM E Tfl ES Groundwater Flow Direction Figure 4.4-4 GROUNDWATER FLOW REGIME IN CANADIAN PART OF POPLAR RIVER BASIN OPEN PIT COAL MINE (AREA LIMIT FOR FIRST 15 YEARS) LEGEND I)rainage Basin Boundary SuI Basin Bound .iiy 5 106000. Saskac liewan Montatia after Saskmont Engineerirlg, 1978 ------- water flows northward into a series of lakes including Bonneau, Rivard and Montague. The lower East Fork sub-basin flows south toward the border. The East Fork area just north of the International border is a ground water discharge area. The major aquifers in the U.S. part of the basin are the Fox Hills-Hell Creek Formations, Fort Union Formation, Flaxville Formation, Wiota gravels, glacial deposits, and alluvium. The wells supply water for stock and domestic purposes but few wells have high enough yields for large-scale irrigation. The flow regime in the U.S. part of the basin is similar to the topography. Feltis (1978) conducted a detailed study in the East Fork sub-basin from the Canadian border south to the northern boundary of the Fort Peck Indian Reservation. A generalized ground water contour map for the shallow unconfined aquifers is shown in Figure 4.4-5. A detailed ground water level contour map also show- ma the chemical composition is included in Appendix A-4. The direc- tion of flow in the recharge areas at higher elevations is into the upper aquifers--the glacial outwash and Flaxville Formation. The ground water then flows into the Fort Union Formation and partly into the streams and deeper formations. Ground water may flow down the river valley for several miles before discharging into a section of the Poplar River (Feltus, 1978). The detailed flow regime in the southern part of the Poplar River was not available. The expected flow directions are from the basin divides toward the river and then down to the Missouri River. Primary recharge areas in the U.S. part of the basin are the plateaus and terraces along the sub-basin divides. Most of the re- charge is from precipitation within the basin with additional inflow across the International border. Irrigation along tributaries and in the floodplain provides some recharge to the shallow ground water aquifers. At the time of spring runoff (usually March or April) the Poplar River may recharge the Quaternary alluvium. During other per- iods the stored water would return to the river. 4.5 WATER QUALITY 4.5.1 Surface Water Surface water quality data for the baseline year 1975 as requested by the EPA are compared to the appropriate water quality standards and criteria. The sampling stations are located in Figure i.5-1. A statis- tical summary of the data is included in Appendix A-S. Comparing sites on the Canadian East Poplar River (Cl and C6) , water quality appears to deteriorate substantially movina downstream. In general, concentrations of the following water quality constituents increase (based upon comDarisons in Table 4.5-1): ------- - _- - 43 Ground water flow direction Non-contributing areas for surface water — Sub-basin boundaries I I $ I . 5 .- ‘I, 5- > 5- 5.— 0 4- 0 S .- C) E a) C C) 43 -C 0 S .- S.- a) C .) U C) 4 4 I I ,f / 3 \ ____ I Key ------- Figure 4.5—1 LOCATION OF WATER QUALITY SAMPLING STATIONS In I I ------- Table 4.5-1 WATER QUALITY STATISTICS FOR STREAM SAMPLING LOCATIONS IN CANADA 9 2 .120 . .00 lIE I0(sl0 Sampling Dates 5 . 1/ 0 4 7 , 2929) Sb.tiitbc, toM b 102.2 Cood.o- 022.2 *11.1 12vl2 turbid - Sulfite Cob M ig Potts. lobe? lot.) E u /b 5 ,9/b j.t.11/ ity Color 409 sq/a nJ. 0191u. C.luI. n..l,a Oudlie slum i2.,dn.s. 0 P0 4 1,1.1 P tltt.I. to tOll 721 C.20 2 C a L l 2 1a .229 9PttA P0/ b 90 P4/b .9/9 mg/I soJ 9 sq/I Sq/ I .9/I . 9/I sq/b mg/I ag/I ‘o/° 9u llnq p, .iIlon Cl , 24 19 P.pIsr 42.,r, 2. 9 1 02 Co,onaco Sn nlfl—, 414 I/li I/ I 2/’O 2/29, 0/20. 0/24 , 9/IS, 9/00 9/22 Si/I 9/I l b /Il I/ I nit 0/29 SI) 291/I 20/22 Il /lu i l/Il a la b nno 92.. oO 00 20 20 9 20 20 20 20 20 20 20 20 20 20 20 20 20 10 110 04 0 292 9(0 0 0 ito 400 290 9 20 22 0 9 90 20 0 6 20 99 0 0 0 00 00 0 0 I I 0 992 990 202 20 0 204 292 0 42 90 0 22 0 92 2 920 29 2 392 0222 0220 202 401 22 2 003 909 2990 229 190 999 209 24 0 292 20/ 990 299 200 991 02,9 290 91/3 2 091 9.11 0 204 109 29 0 22 9 290 62 0 2 29 2 92 29 2 22 2 99 0 2 42 99 9 0149 0994 290 / 04 Ii I 9..plloj (.1 ,191.10 C O l..i Poplin Il..r .9 l.Inu.Il..n,i 9.1,nd. ’ 2/24 2/72, 2/20. 7/ ,0 2/20 2/24 4/IS 4/20 9/22 ‘2 0/10 C/lI 1/2 2/11 21/9 0119 9/ I, 20/I il./00 Il/l b 22/22 s # 1 , P .. . 9.. 5 72 9 22 22 22 20 22 22 22 72 22 22 22 22 22 22 22 22 22 22 2 40 240 209 230 490 00 290 ES 0 0020 240 09 0 200 22 0 99 204 00 020 00 02 202 35 4 022 2290 209 22 0 2020 0/2 079 066 92 0 96 2 249 22 0 020 0920 0942 2 51 511 1’ 0 0 92 040 122 2020 29 0 900 iro too 209 22 0 900 620 9?) 04 0 444 290 29’ I 20 I 2/ 94 0 29 9 240 929 2) 9 2/ 2 202 Li 9 00 4 22 22 0 20 0 220 299 24 0 09.47 02/2 92.92 it) It 9 ------- e Total alkalinity . Sodium o Conductance 0 Potassium • Color o Orthophospnate • Total dissolved solids a Total phosphorus • Sulfate • Total nitrate • Chloride 0 Ammonia o Silica a COD • Macnesium These parameters probably exhibit an increase because of the influx of Girard Creek water, which includes Fife Lake discharge. Since Fife Lake discharges only intermittently, the waters are high in dissolved solids due to evaporative concentration. Only turbidity, calcium, and total hardness do not increase or decrease slightly. Mercury values measured in walleye tissue from the Cookson Reser- voir were up to 1.5 ppm which exceeds the Canadian standard of 0.5 ppm. Mercury levels measured in walleye tissue from the East Fork on the U.S. side were up to 0.9 ppm which is close to the new FDA standard of 1 ppm (U.S. EPA, personal communication, 1980). Limited water column measurements of mercury indicate that mercury is present in all the forks and that the accumulation rate in the fish is high. Mercuric acetone is widely used as a fungicide for treatment of wheat seeds throughout the basin. More work is currently being done by the USGS and EPA on this problem. The East Fork below the International boundary had total dissolved solids concentrations between 1050 and 1750 mg/Q in 1975. Sodium con- centrations are fairly high with a mean up to 486 mg/i. Boron concen- trations ranged between 2.5 and 3.7 mg/i in the summer of 1975 at the border and 1.5 to 3.2 mg/Q at station G, close to the confluence with the Middle Fork. Dissolved oxygen varied from 4.4 to 12 mg/i suggesting that levels may be low for fish during the winter. As elsewhere in the Poplar River system, the water is very hard, calcium-magnesium hardness typically being in the 300-400 mg/i range (as CaCO 3 ). Sulfate levels in the water are high (mean of 306 mg/i) as are both nitrogen (mean of 1.46 mg/i) and phosphorus (mean of 0.09, maximum of 0.4 mg/i). Data for the West Fork are limited to three stations in the summer of 1975. Water quality appears relatively uniform, especially with respect to dissolved solids concentration which is low (mean of 700-800 mci/i TDS) relative to the East Fork. Dissolved oxygen appears to de- crease slightly from upstream to down, but is high in all samples. Boron levels rance from about one-half to slightly over 1 ppm. 46 ------- Data for the Middle Fork are also limited. Dissolved solids in the Middle Fork are high (maxima slightly above 1000 mg/P.. TDS). Sus- pended solids, are similarly hicih (up to 76 mg/i SS) and may, at times, be stressful to aquatic biota. Boron levels are uniformly high (observed values of 0.36 to 2.0 ma/i) in the Middle Fork, and the water is likely to be toxic to sensitive crops grown under irrigation. The water is also hard with a range of 200-300 ppm of calcium-magnesium hardness. Dissolved oxygen concentrations are quite variable with a range of 4.6 to 8.2 mg/i at the border station. Water quality data in the mainstem of the Poplar River show mean TDS concentrations above 1000 mg/Q. Sodium concentrations are high with means of 300 mg/i. Calcium and magnesium levels are similar to those in the other forks, and the water is classified as very hard. Boron levels are high, observations as high as 3.4 ppm having been made at station PR-4. Apparently, however, boron levels decrease down- stream as the water approaches the confluence with the Missouri River. Phosphorus and nitrogen levels (based upon only three observations at USGS station 06181000) appear significantly lower in this part of the system than elsewhere. The dissolved oxygen concentrations are about 5 mg/i. Federal Drinking Water Quality Standards . Available data for 1975 show that the only Federal primary standard for drinking water quality contravened was lead on the main stem and the East Fork. How- ever, since the concentration values were reported as being “less than 100 ug/Z,” there may, in fact, have been no contraventions at all. The secondary standards for iron, manganese, pH, and TDS were contra- vened in at least one observation on all four branches of the river. Sulfate concentrations exceeded the secondary drinking water standard on the Middle and East Forks and on the main stem. There were insuffi- cient data to evaluate barium, silver, chlorinated hydrocarbons, tur- bidity (because of units) and coliforms (all primary contaminants) and methylene blue active substances, hydrogen sulfide, and odor (secondary contaminants). Federal Water Quality Criteria . Table 4.5-2 shows criteria and the locations where one or more contraventions occurred in 1975. The criteria for boron and iron are contravened in all four branches of the river. In all but the main stem, mercury values have apparently exceeded 0.05 iig/i, and in the East Fork, manganese has exceeded 0.1 mg/i. With respect to barium, fecal coliforms, color, cyanide, and nickel, data were inadequate to evaluate for criteria contraventions. In all other cases, existing data for 1975 did not show levels to be in excess of criteria. State Water Quality Standards . Montana State water quality standards for waters of B-D 2 classification (including the Poplar River Basin) are, with the exception of toxic substances and fecal coliforms, expressed in terms of anthropogenic increases above, or changes in, natural conditions. Standards cover pH, dissolved oxygen, sediment, turbidity, and color. 47 ------- Table d.52 U.S. EPA WATER QUALITY CRITERIA CONTR. VE TIONS O I THE POPLAR RIVER, 1975 Branch of River 3 Parameter Standard ’ F West Fork Middle Fork East Fork Mainstem Alkalinity as CaCO 3 20 Ammonia .O2 Arsenic .10 Barium 1.0 X Beryllium ii ug/Q Boron .75 o a Chromium .10 Fecal coliforms 6 X 75 Pt-Co Color units Cyanide .005 X Iron 1.0 9 0 Manganese .10 a Mercury .05 ig/Z’ a NickeF x Dissolved Oxygen 5 9 a pH 5-9 units a a a Hydrogen Sulfide .002 Notes ‘In mg/ except as noted. ifl this column means inadequate data to evaluate. ‘“a” in these columns means one or more kno ’ in contraventions. Un onized ammonia, a function of pH ann temperature 5 Most stringent, for protection of aquatic life in soft, fresh .sater . °Depends upon method of assaying. 7 For protection of fresft.iater aquatic life and iildlife. Defined in terms of the LC5O for aquatic life. ------- Toxic substances are considered in the same way, i.e., with respect to anthropogenic increases, but also with regard to Federal drinking water standards. These were discussed earlier. Fecal coliforms are consid- ered in terms of proportions of samples having more than some number of organisms per unit volume during a set time period. The available data are inadequate to evaluate coliforms contraventions. 4.5.2 Ground Water fluality Ground water quality data were available for 65 wells in Canada and 20 in the U.S. Detailed water quality data tables are included in Appendix A-S. The following section describes the general chemical water types found in the basin. The water in all formations except the Flaxville Formation is alkaline and high in total dissolved solids (TDS). The data show a sodium bicarbonate type water in the alluvium and Fox Hills-Hell Creek Formation although the latter may contain some carbonate. The Fort Union Formation may have a sodium or magne- sium bicarbonate water. One sample from the Flaxville Formation was lower in dissolved solids with more calcium than magnesium or sodium. The available data for the Canadian wells show a similar pattern to the U.S. wells with the glacial drift water a calcium and magnesium bicarbonate type. The Ravenscrag Formation samples were a sodium bicarbonate-sulfate type water with very low calcium and magnesium. One of the major uses of ground water in the basin is for domestic water supplies. The available data were compared to the U.S. EPA pri- mary and secondary drinking water standards. Figures 4.5-2 and 4.5-3 show the range of water quality data for selected parameters and the standards. A detailed description of the standards is included in Appendix A-S. Ground water is used for stock watering in approximately 72 per- cent of the wells and springs in Daniels and Roosevelt counties (Kiarich, 1978). Water quality guidelines for livestock from the EPA, Montana, and the California State Water Quality Control Board were compared with the available data. The Fox Hills-Hell Creek Formation samples exceeded the guidelines of 1 mg/2 Fluoride and 500 mg/2. HCO 3 . Water samples from the Fort Union Formation and Quaternary alluvium also contained HCO3 above 500 rng/Q. One sample from a well completed in the Fort Union Formation had sulfate levels above the threshold value of 500 mg/Z. One sample from a well completed in the Fort Union Formation had sulfate levels above the threshold value of 500 mg/9. but belo i the limiting value of 1000 mg/2 . Guidelines were met for the following selected cations and heavy metals: 49 ------- FORT L4ON Fo . I1 L!s I I Cl Il Fn, 1 10 1000 10000 TOO — — S — flLC* I’.ITV “I , . 0*00 1 . 1 5 0 — C I M 1 1 100 .N W I _____, S C ’ C. — ———-—C———— N. _____ _____ 0 • I - S I , _•____ —“j r * 1 Pb .4 , 0 Cd ‘4” —--—- ———-- C. . 4 ( 0 5. ‘ 4, . LI C- 4” S — R .GE MEAN US F’ IARY DO .Cl 1 .Q WATER ST .\OL005 — FORT UT.I( lTI FORVAT O ’ FOb HILLS ‘(t CR 500 FC’°S1AT ,C Data from Feltis, 1978 and U.S. EPA. 1977 Figure ‘1.5-2 RANGES OF SELECTED CHEMICAL PARAMETERS IN WATER SAMPLES FROM THE FORT UNION FORMATION AND FOX HILLS-HELLS CREEK FORMATION IN U.S. PART OF THE POPLAR RIVER BASIN 50 ------- CUiTER MRY . LLUVlU’. Glacial Oorwasn inc FIan,llt Fc,r,at.on 0 IC O • —3—- —4,, = U I •—-o- £LkALI&Itv c.— I IC. MV :————-- C—. Cl — “‘4,’ - - -V. - - -, ‘.4 -0 F. • >— — I ” , ” U 4, ’ ___Q____. . 4 , U —-—3.— “4 Pb - i’ ll Cd A, —4 9. -3 S. I — ‘ —————4 EEl — RA ’ aGE • US P I . 4RY DRI I ’G 5d 9TER SI. AI’)S — FORT U%ION FO allaN FOX “ILLS HELL CPEEE FCPMATION __________ - _j Data from Feltis, 1978 and U.S. EPA, 1977 FiQure 4.5-3 RANGES OF SELECTED CHEMICAL PARAMETERS IN WATER SAMPLES FROM QUATERNARY ALLUVIUM, GLACIAL OUTWASH AND FLAXVILLE FORMATION IN THE U.S. PART OF THE POPLAR RIVER BASIN 51 ------- • Calcium o Copper • Magnesium • Fluoride o Sodium • Lead • Arsenic a Mercury o Aluminum • Nitrate + Nitrite • Boron • Nitrite o Cadmium o Selenium o Chromium o Vanadium • Cobalt o Chloride The TDS concentrations in the ground water would classify the water as good (less than 2,500 mg/Z) by Montana’s salinity classification. Water from some of the wells completed in the Quaternary and Fort Union Formations would be classified as excellent (less than 1,000 mg/2 ) under the EPA’s system (EPA, 1975). Small numbers of wells are used for irrigation. The ground water in the basin would be assigned to Class II of McKee and Wolf (1963) on the basis of the high conductance, TDS, sulfate, and sodium concentra— tions. Class II ground water has a medium to very high salinity hazard and is suitable for irrigating tolerant to semi-tolerant crops includ- ing barley, hay, alfalfa, and wheat. A recent study by Klages (1976) investigated the irrigation potential and hazards of irrigation in the Poplar River Basin. This study recommended a limit of 1,500 imhos/cm for conductance (at 25°C) and SAR values (sodium adsorption ratio) less than 7.5 to 8. Water from the glacial outwash deposits, the Flaxville Formation and a few wells in the Quaternary alluvium and Fort Union Formations could be used for irrigation based on these criteria. Boron levels in the glacial outwash and Flaxville Formation are less than 0.67 mg/2 so the water could be used for sensitive crops. Boron concentrations in the Quaternary alluvium and Fort Union Formation are mostly between 1.4 and 2.4 mg/9 . which would be suitable for semi- tolerant or tolerant crops. Other elements which exceeded guidelines in at least one well were manganese, fluoride, molybdenum, iron, and selenium. In the Canadian part of the basin most wells are used for domestic water supplies and stock-watering. The range of chemical parameters and the Canadian and Saskatchewan standards for drinking ‘.iater, stock use and irrigation are discussed in detail in Append x A-5 52 ------- 4.6 WATER USE d.6.1 Municioal Use In the U.S. part of the basin the only municipal water use is by the City of Scobey, Montana. The water is pumped from shallow wells adjacent to the Poplar River at a current capacity of about 750 gpm (3.31 acre-feet/day). The wells are considered to be recharged from the Poplar River. During 1975, municipal water use by Scobey was 210 gal/person/day, or a total of 0.95 acre-feet-day (Montana DNRC, 1978). This represents an annual use of about 347 acre-feet. In Canada the only municipal water use is a shallow well located adjacent to Coronach Reservoir serving the Village of Coronach, Sas- katchewan. In recent years the annual water use has ranged from 20 to dO (average 36) acre-feet. It is assumed that almost all of the use represents a surface water depletion (Poplar River Task Force, 1976). 4.6.2 Industrial Use There is currently no industrial use of water in the U.S. or Canadian parts of the Poplar River Basin. The Farmer’s Potash Company has applied for a permit in Montana but this has been delayed pending outcome of the apportionment. 4.6.3 Agricultural Use Consumptive water use for agricultural purposes is associated with stock watering and irrigation. Water consunption for stock watering activities results from two separate actions: evaporation from stock ‘.‘iater holding reservoirs and actual consumption by livestock. In the U.S. part of the basin, information on water use projects for agricultural purposes has been estimated based on water resource surveys, field inspections and aerial photographs. In the Canadian basin data were also available from project owner’s records of pumping rates. This information was then used in conjunction with assumptions on crop requirements, soil characteristics and water availability to estimate total water use. The assumptions used for both U.S. and Canadian parts of the basin are listed in the Poplar River Task Force Report (1976). 4.6.3.1 Montana Water Use For the U.S. part of the basin outside of the Fort Peck Indian Reservation, the 1975 water use for livestock was 432 acre-feet for stock watering and 452 acre-feet due to reservoir evaporation (Montana DNRC, 1978). 53 ------- The historical use of water for irrigation by gravity/pump diver- sion is variable depending upon river flow (Figure 4.6-1). Since 1960 there has been a large increase in irrigation usage which has generally fluctuated between 2,500 and 5,000 acre-feet per year in the U.S. part of the basin. In 1975, a total of 5,900 acre-feet was used for irrigation by gravity and pumping and 3,076 acre-feet by spreader irrigation in the U.S. basin exclusive of the Indian Reservation. This relatively high water usage reflects the correspondingly high availability of water during 1975, which allowed for a total of four applications. During the last 45 years there have been only three years, however, in which water availability in the basin allowed for four applications. During the period of record, the average number of applications was 2.4 (Dooley, 1975). A breakdown by sub-basin of irrigation water usage in the non-Indian Reservation U.S. part of the basin is shown in Appendix A-5. 4.6.3.2 Water Use on the Fort Peck Indian Reservation On the Fort Peck Indian Reservation all existing (1975) water uses are associated with agricultural activities. A detailed breakdown by sub-basin is shown in Appendix A-5. In a survey conducted by the Fort Peck Sioux and Assiniboine Tribes and Morrison-Maierle, Inc. (1978), a total of 283 stock ponds were identified on the reservation. The total water uses for livestock consumption and evaporation were 287 acre- feet and 600 acre-feet, respectively. A total of 12 existing irrigation projects were also identified. Of these, four projects used gravity or pump diversion systems to irri- gate alfalfa, native hay, truck gardens or barley. The total acreage used for gravity/pump systems in 1975 was 306. Estimates were also available for the actual water use in irrigation projects during 1975. Since 1975 was a high runoff year, four irrigation applications were conducted. Based on a total application of about 31 inches, the esti- mated use was 785 acre-feet. All of the 1975 use associated with gravity/pump irrigations was from two sub-basins of the Mainstem of the Poplar River (boundary to West Fork and Hay Creek to Missouri River). An additional area of 299 acres on the Indian Reservation was irrigated by eight spreader dike systems during 1975. Based on a single 10-inch aoplication, the total water use was estimated at 299 acre-feet. Crops irrigated by spreader dikes were alfalfa and native grasses. During the period from 1955 to 1975, consumptive water uses on the Indian Reservation for stock watering and spreader irrigation have re- mained relatively constant (Figure 4.6-2). The annual water use for gravity/pump irrigation has fluctuated from about 300 to over 1,500 acre-feet. During this period the total area irrigated by gravity/pump 54 ------- 5.0 4.0 3.0 2.0 1.0 0 1955 Ficiure 4.6-1 1960 1965 1970 1975 YEAR HISTORICAL WATER USE IN THE U.S. PART POPLAR RIVER BASIN 1955 THROUGH 1974. from Poplar River Task Force, 1976) OF THE (Data C I- x U- U LU C l ) LU I.-. 55 ------- 2000 1500 — a, C., LU 1000 ‘I ) LU I . .- 500 — I I I I I I I I I I I I I I I I I I I I I 1955 1960 1965 1970 1975 YEAR Figure 4.6-2 HISTORICAL WATER USES ON THE FORT PECK INDIAN RESERVATION 1955 THROUGH 1965. (Data from Morrison-Maierle, Inc. 1978) Stock Consumption . & a . Stock Pond Evaporation • Gravity/pump • Spreader . 0_ A 56 ------- systems varied from 236 to 786 acres. Much of the fluctuation in water use was due, however, to water availability and subsequent variations in the total number of irrigations per season. Since 1975 was a high runoff year, the actual irrigation uses are probably not representative of the average existing water use at the 1975 level of development. Existing water use for gravity/pump irriga- tion is more appropriately defined by using 1975 levels of development (i.e., irrigated acreage) and average runoff values. Table 4.6-1 pre- sents estimates of existing water use in the U.S. part of the basin assuming 2.4 irrigations per year and 0.641 feet per application (Poplar River Task Force, 1976). The use of these assumptions modifies only the gravity/pump irrigation uses, since stock uses and spreader dikes are less dependent upon the amount of runoff. 4.6.3.3 Canadian Water Use In the Canadian part of the basin water use for agricultural pur- poses is associated with stock watering (consumption and pond evapora- tion), irrigation, and evaporation from several large reservoirs. Agricultural uses for stock watering and irrigation under exist- ing conditions are 182 and 319 acre-feet, respectively. The existing uses for each sub-basin in Saskatchewan are given in Appendix A-5. With an additional 620 acre-feet use due to evaporation at three reser- voirs (Clarke Bridge, Coronach and West Poplar), the total agricultural water use is 1,523 acre-feet. 4.7 VEGETATION AND WILDLIFE The Poplar River Basin is dominated by cropland (wheat, barley and alfalfa) and grassland areas. The grasslands are comprised of a variety of grasses including: crested wheatgrass, yarrow, blue gramma and bluegrasses. Although coulees and breaks may contain areas of shrubs (e.g., rose, silver sage and chokecherry), there are very few stands of deciduous trees. The existing aspen poplars and green ash are confined primarily to the banks of the Lower Poplar River near its confluence with the Missouri River. The Poplar River Basin provides important habitat for upland game- birds, big game and waterfowl. Major upland gamebird species include the ring-necked pheasant, Hungarian partridge and sharp-tailed grouse. White-tailed deer is the main big game species; however, lower densi- ties of mule deer and pronghorn antelope are also present. The occur- rence of rare and endangered species is discussed in Appendix A-6. 57 ------- Table 4.6-1 ESTIMATES OF EXISTING WATER USE FOR GRAVITY/PUMP IRRIGATION IN THE U.S. POPLAR RIVER BASIN Estimated Acres Water Use* Sub-basin Irrigated ( acre-feet ) International Boundary to Fort Peck I.R . East Fork 65 100 Middle Fork 1,269 1,950 West Fork 389 598 Poplar River (main stem) 976 1,500 Maternach Coulee 137 211 Sub-Total 2,836 4,359 Fort Peck I.R. to Missouri River Poplar River to West Fork 250 384 Poplar River-West Fork to Missouri River 56 71 Sub-Total 306 470 TOTAL 3,142 4,829 *Based on 2.4 applications per year and 0.641 ft of water per application. Acreage is partly irriqated by small tributaries to the East Fork. The only diversions are near the confluence with Middle Fork. Source: Poplar River Task Force (1976) -J ------- The aquatic habitat provided by the Poplar River is important for significant breeding populations of waterfowl such as mallards and American wigeons. The potential use of the river by waterfowl is an important consideration since flow modifications due to apportionment could result in changes in available nesting and rearing habitat. Studies of waterfowl utilization of the Poplar River have been con- ducted by DeSimone (1979) and are discussed fully in Appendix A-6. Also included in the Appendix are detailed discussions of the vege- tation types and terrestrial wildlife studies conducted in the study area. 4.8 AOUATIC BIOTA AND FISHERIES The Poplar River supports relatively abundant game fish popula- tions. In this regard it is distinct from most northern plains streams which are not generally considered as game fish habitat. The primary game species in the Poplar River Basin is walleye; however, northern pike are also common in most of the area. Smailmouth bass have been stocked and are apparently reproducing successfully in the main river near its confluence with the West Fork. Goldeye are also utilized by anglers; however, they are primarily restricted to the lower river. Although the Poplar River supplies good fishing quality throughout much of the drainage basin, the actual angler utilization is low. Montana Department of Fish and Game has estimated that the entire Poplar River received a fishing pressure of only 2660 angler-days per year (State of Montana, DNRC, 1978). This represents an average usaae of only 7.3 anglers per day of fishing throughout the year. The low fishing pressure is also reflected in the local Daniels County fishing license sales, which have averaged only 349 per year (1966-1976). Due to the low population density, lack of projected population increases (see Section 4.10) and the proximity of popular fishing areas (e.g., Fort Peck Reservoir), it is anticipated that the Poplar River will continue to be utilized by anglers at a low level of fishing in- tensity. It is also expected that the usage will be primarily by local anglers. Studies conducted by Montana Department of Fish and Game (1978) reveal that gamefish spawn throughout much of the U.S. Poplar River. Both walleye and northern pike require distinct spawning habitats in the Poplar River Basin. Walleye spawn over gravel bottoms in shallow water riffle areas while pike commonly use streamside vegetation as a spawninG substrate. Both species spawn during high flow conditions following the spring ice breakup. Therefore, modifications of the natural flow regimes due to the apportionment may potentially impact gamefish spawning success and subsequent recruitment. 59 ------- Studies of periphyton, macrobenthos and fish of the Poplar River have been conducted by Bahis (1977), Montana Department of Fish and Game (1976 and 1978), Saskmont Engineering (1978) and the IJC, 1979 (DeSimone, 1980). The results of these studies provide for a general discussion of the aquatic biology of the river which is included as Appendix A-7. 4.9 METEOROLOGY AND AIR QUALITY 4.9.1 Meteorology The climate of the Poplar River Basin is controlled largely by high pressure areas which move into the area from the north during the winter and from the west during the summer. The major tracks of low pressure centers pass either to the north or south of the area throughout the year. The area is in the rain shadow of the Rocky Mountains, resulting in a semiarid climate with a large annual range in temperature. Cold winters and warm summers are characteristics of the regional climate. The average monthly temperature at Scobey is above freezing between April and October. Detailed temperature data are presented in Appendix A-8. The precipitation at Scobey ranged from a low of 7 inches to a high of 21.9 inches for the period 1940 to 1978. The average precipi- tation at Scobey from 1941 to 1970 is 13.6 inches. Monthly precipita- tion for Scobey is shown in Figure 4.9-1. While the normal annual precipitation for the area is only 11 to 14 inches, 76 percent of it falls from April through September, with May and June accounting for 34 percent of the annual total. Winter precipitation nearly always falls as snow; but as a rule, although snow seldom accumulates to any great depth, it usually is formed into drifts in the open, unprotected areas. Accumulated winter snow remains on the ground until about March. Wind plays an important role in the dispersion and dilution of pollutants emitted into the atmosphere. Pollutant concentrations are inversely proportional to wind speeds, i.e., the stronger the wind the lower the pollutant concentrations. The Poplar River Basin is charac- terized by relatively high winds and few periods of calm. Mean monthly wind speeds at Scobey typically range from 8 to 13 knots with calm winds occurring from 0.5 to 6 percent of the time on an annual basis. The higher wind speeds occur in the autumn and spring months from the northwest. The prevailing winds at Scobey are from the northwest or southeast. Wind rose plots are included in Appendix A-8 for Scobey and Glasgow, Montana. 60 ------- Ficiure 4.9-1 Normal Monthly Precipitation at Scobey, Montana 61 5 4 3 2 0 U) -c U C a C 0 0 0 U 0) 3- Months J A N ------- 4.9.2 Existing Air Quality The existing air quality in the study and impact area is very good. Recent measurements taken by the Montana Air Quality Bureau, during 1979, in northeastern Montana have shown very low concentrations of S02, NO 2 and particulates (Geihaus, 1977, 1979). Since there are no major sources of pollutant emissions in northeastern Montana, these results might have been anticipated. A comparison of these values with the National and Montana ambient air quality standards shows that S02, N02 and suspended particulates concentrations are well below standards. A further discussion of existing air quality and air quality standards in included in Appendix A-8. 4.10 SOCIAL AND ECONOMIC PROFILES 4.10.1 Population Profile The population and average annual percentage change in population between 1970 and 1975 are shown for Daniels and Roosevelt counties in Table 4.10-1. Population has changed very little in Daniels County, remaining stable at about 3,100 throughout the five-year period, 1970- 1975. Slight variations in population shown in Table 4.10-1 were due to changes in estimating procedure rather than actual changes in popu- lation. The size of the population also remained stable in Roosevelt County. There were approximately 10,300 people living in the county between 1970 and 1975 (see Table 4.10-1). The occasional fluctuations are due either to estimating techniques or to actual small population changes. Detailed population profiles by age, sex, and race are in- cluded in Appendix A-9. The total population on the Fort Peck Indian Reservation was 9,898 in 1970. Indians made up 34 percent of the population, or 3,406. The number of Indians almost doubled in a three-year period to 6,202 in March, 1973. Small population increases are projected for Daniels and Roosevelt counties. In Daniels County, between 1980 and the year 2000 an increase of 300 persons is projected, increasing the population from 3,100 to 3,400. The increase will be largely due to the construction and opera- tion of a proposed potash plant which should begin in roughly 1990. In Roosevelt County, the population is expected to increase from 10,700 to 11,500 between 1980 and 2000. The increase in employment due to oil and gas industries and exploration will increase the county population and counteract the declining agricultural opportunities (Department of Community Affairs, 1978). 62 ------- Table 4.10-1 POPULATION IN DANIELS AND ROOSEVELT COUNTIES, 1970-1975, AND PERCENTAGE CHANGE, 1970-1975 Average Annual Percent Change County 1970 1971 1972 1973 1974 1975 1970 — 1975 Daniels 3,083’ 3,0002 3,1OO 3,100’ 3,200’ 3,1OO 0.1% p p Roosevent 10,365’ 10,4002 10,6O0 10,300’ 10,500’ 10,3OO -0.1% Sources: ‘Bureau of the Census, Current Population Reports, Federal-State Cooperative Program for Population Estimates, Series P-26, No. 109, May, 1975. 2 Bureau of the Census, Current Population Reports, Population Estimates and Projections, Series P-25, No. 517, May, 1974. 3 Bureau of the Census, Current Population Reports, Federal-State Cooperative Program for Population Estimates, Series P-26, No. 53, February, 1974. 1 ’Ibid, Series P-26, No. 76-26, July, 1977. p = preliminary ------- 4.10.2 Archaeological and Historical Sites There have been no archaeological sites identified in Daniels County to date. However, the county is rated as having high future archaeological potential. Seven archaeological sites of various types have been identified within Roosevelt County. The county is also rated as having a high future archaeological potential. There are no nationally registered historical sites within Daniels County. However, within Scobey there is a private historical site, Pioneer Town. It is a representative pioneer homesteader town of the early 1900’s that has been created by combining many authentic early structures and objects from throughout the county. The Fort Peck Agency and Fort Union Trading Post are national registered historical landmarks within Roosevelt County. Fort Peck was originally a fur-trading post, then an Indian Agency. Fort Union Trading Post was an important early upper-Missouri fur trade depot. There are also six private historical sites within the county, four of which were trading posts. Fort Jackson and Fort Poplar are located near Poplar. Fort Kipp and Fort Stewart are located west of Culbertson. Disaster Bend and Snowden Bridge are the other private historical sites (Figure 4.10-1). 4.10.3 Economic Profile The size of the labor forces in Daniels and Roosevelt counties declined between 1960 and 1970; however, both counties have experienced increasing labor forces since 1972. The 1977 unemployment rates in Daniels and Roosevelt counties were 2.9 percent and 5.1 percent, re- spectively. Detailed information on employment rates, income and business activities are included in Appendix A-9. 64 ------- Historic Places 0 National Park Service Areas Location of Disaster Bend, Fort Jackson and Fort Poplar Figure 4.10—1 LOCATION OF HISTORIC SITES IN THE POPLAR RIVER BASIN AND ADJACENT AREAS -- — Saskatchewan asS - Sheridan County - - ci1oi tana P,cneer TCwfl Plentywood “. Northern Boundary I ForkPeck IR Tt Hills Medicine Lake • National Wildlife Refuge i - Roosevelt County Miles o 4 8 12 o 6 12 18 Kilometers Fort Kipp Fort Stewart cSrt ..1 CS Trading st 65 ------- 5. ENVIRONMENTAL CONSEQUENCES 5.1 AIR QUALITY IMPACTS 5.1.1 Air Quality Model To estimate the projected air pollution concentrations in the “impact area”, the Environmental Protection Agency air quality Single- Source (CRSTER) Model was selected. This model was employed because it was determined that the Poplar River Power Plant would be the only significant contributor to the pollutant burden in the impact area through the year 2000. This model is also suitable to the flat or slightly rolling terrain which is found in the impact area. The Single Source (CRSTER) Model is a steady-state Gaussian plume dispersion model designed for point-source applications. It calcu- lates pollutant concentrations for each hour of a year at 180 receptor sites on a radial grid. The hourly concentrations are averaged to obtain concentration estimates for time increments of specified length, such as 3-hour, 8-hour, 24-hour and annual. The model contains the concentration equations, the Pasquill-Gifford dispersion coefficients and the Pasquill stability classes. Plume rise is calculated according to Briggs. No depletion of the pollutant is considered. A complete description of the model is presented in Appendix C. 5.1.2 Power Plant Emissions The emission rates for the power plant were obtained from the U.S. Environmental Protection Agency (EPA) Regional Office in Denver, Colo- rado. The following emission rates were employed in the model. Emission Rate for 600 MI.J Plant Pollutant ( pounds/hour) ( g/seconci ) Sulfur Dioxide (SO 2 ) 10,732 1352.2 Particulate (TSP) 450 56.7 Oxides of Nitrogen (NO ) 3,600 453.6 The emission rates are for a 600 MW plant with a single stack. The °2 emission rate was calculated on the basis of 1.94 pound S0 2 /10 6 Btu heat input and about 8 percent sulfur retention. The particulate emissions employed 99.5 percent control and 0.08 pounds/1O° Btu. The NO emissions utilized a 0.60 pound/10 6 Btu rate. The EPA new source performance standards for 502, TSP, and NO < are 1.2, 0.10, and 0.70 pounds per i06 Btu, respectively. 66 ------- 5.1.3 Model Input Parameters The emission rates employed in the model are shown in the previous section (5.1.2). The stack data that were employed for plume rise height computation were obtained from the EPA Regional Office in Denver and are as follows: Stack Data for 600 MW Plant • Number - 1 • Height, meters - 122.0 o Diameter, meters - 7.4 • Exit velocity, meters/sec - 24.4 o Exit temperature, °K - 424 The meteorological data employed were hourly surface observations from Glasgow, Montana and twice daily mixing heights for the year 1964. The year 1960 was also employed to determine if there were any signifi- cant differences in peak concentrations of pollutants for the two years since temperature and wind conditions were quite different during the months of January and February. The mean temperatures for these months were 10 to 15 degrees colder, and the frequency of calms was about seven percent higher in 1960 than in 1964. The meteorological data were ob- tained on magnetic tape from the National Climatic Center.in Asheville, North Carolina. Recently, a continuous meteorological monitoring station has been set up at Scobey. The air quality model will be rerun with the new data for the EPA by the Montana Air Quality Bureau. 5.1.4 Modeling Results 5.1.4.1 Sulfur Dioxide (SO 2 ) For SO 2 , the model was employed to obtain maximum concentrations and second highest concentrations in the impact area for averaging times of 1 hour, 3 hours, and 24 hours. The annual concentrations for the year were also obtained. Values were computed at 2 kilometer (km) intervals along 10° radials out to a distance of 50 kilometers from the plant site. Calculations were not made for greater distances, because the basic assumptions incorporated into the model cause the results to be suspect at greater distances. However, concentrations at distances greater than 50 kilometers should become less as the distance increases. Spatial distributions of the highest maximum short term concen- trations (1 hour, 3 hours, and 24 hours) and the 1964 annual concen- trations are presented in Figures 5.1-1 through 5.1-4. The isopleths 67 ------- OCKGLEN ) AcH , ‘ / - - - : CANADA “ I • _-1 UUIT ,k AT - - Saskatchewan ___ - , - -___ 9 (1 6%) ç1 (1201 N I t.JLII I f’-, \ WHITETAIL OUTLOOk ( ‘ ‘ - / ( /4 1 t( V ‘ . 4 RAYMOND 6 C. .. .. - / - ‘i,. 120) . I 80 L .‘ / i t t RICKLANO 4 \I “ I REDSTONE I, •FOUR ‘ 60 1 OUTTE ______________ (20 ). 0 PEE (58 PlENTY WOOD op 3 %‘• . . I eo U u (160) ln 4I \\ (120) \ 80 ____ ___________________________________ DANIELS COUNTY (120) (170) DANIELS COUNTY SII(RIDA CO ROOSEVELT COUN Y —4a° I I MEDICINE LAKE _______________ I? ISII ) I 1 La., / lllPlLISL I III ( 0 I MIlPItINC (ARt NAIIOIIAL 1 1 01I 1 1 RUILL FORT PECK JINDIAN RESERVATION / IIWS, )Ia4DL , ( I ROOS(VELT COUNTY > o i ) 7 ‘Rob Figure 5.1-1 SPATIAL DISTRIBUTION OF THE HIGHEST 1-HOUR SO 2 CONCENTRATIONS (pG/M 3 ) OBTAINED FROM THE CRSTER MODEL FOR 1964, ASSUFIING A 600 MW (1200 MW) POPLAR RIVER POWER PLANT WITH ZERO PERCENT EMISSION CONTROL ------- R ESERVATIO 0 OUTLOOK IIlO,AN AISIAVATIO, , SOUPOAP, COOUU Oo .LMpY SOILLTII CONCCNTHA1IONS N i /n N1LRM O ISOPLETH Q , in ’i lAO __ L __ - ———-- •A i -- ,ll t. . Figure 5.1-2 SPATIAL DISTRIBUTION OF THE HIGHEST 3-HOUR SO? CONCENTRATIONS (pG/M 3 ) OBTAINED FROM THE CRSTER MODEL FOR 1964, ASSUMING A 600 MW (12O MW) POPLAR RIVER POWER PLANT WITH ZERO PERCENT EMISSION CONTROL • FORT PE C K ------- 0 rr j T9 T 1 flOUft S S 0 5 W IS I II ? ((IIIAI I II ? —5— I ,op L III CONCINTSIATIONSIN pq1r. RESERVATIO • OUTLOOK IlnI III?? I III — — £ 3L______.. — • $I,rI__ AI Figure 5.1-3 SPATIAL DISTRIBUTION OF THE HIGHEST 24-HOUR SO 2 CONCENTRATIONS (pG/M 3 ) OBTAINED FROM THE CRSTER MODEL FOR 1964, ASSUMING A 600 MW (1200 MW) POPLAR RIVER POWER PLANT WITH ZERO PERCENT EM! SSION CONTROL FO RI PE C K ------- 14 (28) 14 LANT (28) R ESERVAflO b31 (0140 50PI ( I II CONCL0iT11ATtONSINP l&’ INTEIMLO ISOPL1T Q, I0vHKI I:Igure 5.1-4 SPATIAL DISTRIBUTION OF THE 1964 ANNUAL SO 2 CONCENTRATIONS (jiG/M 3 ) OBTAINED FROM TIlE CRSTER MODEL, ASSUMING A 600 MW (1200 MW) POPLAR RIVER POWER PLANT WITH ZERO PERCENT EMISSION CONTROL FORT PE C K ------- are labeled in pg/rn 3 units of concentration. They represent result- ing concentrations with zero percent emission controls. The basic labels are for a 600 MW plant, while those in parentheses are for a 1200 MW plant. Operation of one 300 MW plant would result in pre- dicted concentrations equal to one half of the 600 MW concentrations. The concentration patterns indicate that the highest values occur in general toward the southeast with some secondary peaks toward the south and southwest. The greatest 1-hour concentrations in the U.S. are about 214 .jg/rn 3 for a 600 MW plant and 428 pg/rn 3 for a 1200 MW plant. The highest 3-hour concentrations are 96 pg/rn 3 and 192 pg/rn 3 while the 24-hour concentrations are 21.7 ug/m 3 and 43.4 pg/rn 3 for the 600 MW and 1200 MW plants, respectively. The highest annual con- centrations are about 2.1 pg/rn 3 and 4.2 .ig/m 3 . Detailed tables of model output for 600 MW and 1200 MW plants with zero, 60, and 90 per- cent S02 control are included in Appendix C. Both the tabular and graphical presentations of model outputs indicate that the highest predicted SO 2 concentrations will occur in southerly and southeasterly directions from the plant site. Regions of maximum predicted concentrations are generally confined to the extreme northerly part of the impact area within 15 miles of the Inter- national Boundary. For example, for a 600 MW plant with zero percent S02 control, the maximum annual concentrations (1.8-2.0 pg/m 3 ) would occur on azimuth 120° in the northeast corner of Daniels County (Figure 5.1-4). The predicted elevation in annual SO 2 concentrations for most of Daniels County would be less than 0.6 pg/rn 3 (0.00023 ppm). Although Roosevelt County is beyond the predictive range of the CRSTER model, the annual SO 2 concentrations there (for 600 MW, no control) would be expected to be less than 0.2 pg/rn 3 (0.000076 ppm). 5.1.4.2 Oxides of Nitrogen (N0 ) The spatial distributions of the highest 1-hour concentrations and the annual mean concentrations of NO for the year 1964 are shown in Figures 5.1-5 and 5.1-6, respectively. The general patterns for the NOx distribution are similar to the SO 2 distributions. This is because the meteorological input to the model is the same for both pollutants. In the U.S. the maximum 1-hour concentrations of NOx are about 74 pg/rn 3 and 148 pg/rn 3 for the 600 MW and 1200 MW plants, re- spectively. The highest 1-hour maxima and the second highest 1-hour maxima for 120, 170, and 260 degree azimuths are included in Appendix C for the 600 and 1200 MW Poplar River plants. 72 ------- 0 OUTLOOk RESERVATION St If CUll 4 (I I 45? I4.D4AN RIS(N 1tA1 1044 OtJ4.DASt COIINIV WUNDAHV Pil l.il W*V ISOPLETI I CONLI NTUAIIONS IN 4 INStrHM O ISOPLLTII Q t, l rpu - - -____ - - 454 (4? S4ITLIS Figure 5.1-5 SPATIAL DISTRIBUTION OF THE HIGHEST 1-HOUR NOx CONCENTRATIONS (jiG/M 3 ) OBTAINED FROM THE CRSTER MODEL FOR 1964, ASSUMING A 600 MW (1200 MW) POPLAR RIVER POWER PLANT FORT PE C K ------- 0 OUTLOOK ERVATION MUSS S 0 5 k uMtI(MS 5 0 5 0 5 5— 1)401*50)5)5*0110)4 EIUPIO*IIV COWIITY IOUNOASY ISOPLE TI) CONCI NtI)ATIONSIN jo/,., INTI I IMED ISOPLSII4 I l lS) lOSt — . ‘ I 4* ) — — _________ — — •0 J — 5ILTL, *l • 000LEY Figure 5.1-6 SPATIAL DISTRIBUTION OF THE 1964 ANNUAL NOx CONCENTRATIONS (pG/M 3 ) OBTAINED FROM TIlE CRSTER MODEL, ASSUMING A 600 MW (1200 MW) POPLAR RIVER POWER PLANT • POUR / FORT PE C K ------- 5.1.4.3 Particulates The spatial distributions of the highest 24-hour concentrations and the annual mean concentration of particulates for the year 1964 are shown in Figures 5.1-7 and 5.1-8. These concentrations are for a 99.5 percent controlled particulate emission. For a 99 percent emis- sion control all the isopleth concentration values should be multiplied by a factor of 2. From these maps the following maximum 24-hour and annual particulate concentrations ( ig/m 3 ) were estimated for Montana: 600 MW Plant 1200 MW Plant 99 Percent 99.5 Percent 99 Percent 99.5 Percent Control Control Control Control 24 hour 2.0 1.0 4.0 0.18 Annual 0.18 0.09 0.36 0.18 5.1.4.4 Comparison of Model Outputs for the Years 1964 and 1960 A comparison of SO 2 concentrations was made between the years 1964 and 1960. As indicated previously, the winter months for these two years differed in both wind and temperature conditions. A compar- ison of the 1-hour and 3-hour maximum concentrations showed very little difference between the two years. However, the maximum 24-hour con- centrations in 1960 were about 31 percent higher than in 1964, and the 1960 annual concentrations were about 10 percent higher than those obtained in 1964. 5.1.5 Impact Assessment Table 5.1-1 presents the estimated maximal pollutant concentrations occurring in the U.S. impact area as a result of the operation of a 600 MW or a 1200 MW Poplar River power station. For comparative pur- poses, the U.S. and Canadian National Ambient Air Quality Standards and the Montana and Saskatchewan standards are also shown in Table 5.1-1. The 502 concentrations assume a zero percent emission control while the particulate concentrations are based on a 99 percent emis- sion control. All the concentrations are based on the maximal values obtained from the CRSTER Model for the years 1960 and 1964. 5.1.5.1 Sulfur Dioxide Impact The SO 2 measurements made by the Montana Air Quality Bureau showed the 24-hour averaged SO 2 concentrations to be less than 26 iig/m 3 , which was the minimum detectable level of the instrumentation. 1axima 24- 75 ------- R ESERVATIO OUtLOOK — INDIAN AISAIIVAIIOSI IOUNOANI COL,NI I IOUIIIJAIIY V . 1 , 11 WA V ISflPI liii CON( ,ENTU*TIONS IN INTEHMEO ISOPL(TII Q I,,sI SA IL __L L_ .. i _.____ AA 5 ,LSL.. I l Figure 5.1-7 SPATIAL DISTRIBUTION OF THE HIGHEST 24-HOUR PARTICULATE CONCENTRATIONS (jjG/M 3 ) OBTAINED FROM THE CRSTER MODEL FOR 1964, ASSUMING A 600 MW (1200 MW) POPLAR RIVER POWER PLANT WITH 99.5 PERCENT EMISSION CONTROL FORT PE C K ------- O (0 — / , 0 OUTLOOK 1 10 , 1* A, usopi r r C(JNCINTHATIONS IN p INTLHMLD I OPtiTiI I lls’,”, _ IIA __ “‘°‘ A41 1 AM ERVATIO Figure 5.1-8 SPATIAL DISTRIBUTION üí THE 1964 ANNUAL PARTICULATE CONCENTRATIONS (pG/M 3 ) OBTAINED FROM THE CRSTER MODEL, ASSUMING A 600 MW (1200 MW) POPLAR RIVER POWER PLANT WITH 99.5 PERCENT EMISSION CONTROL .1 1T(llft .U I4At FORT PE C K ------- Table 5.1-1 PROJECTED IIAXIMA POLLUTANT CONCENTRATIONS ( 1g/m 3 ) IN UNITED STATES IMPACT AREA COMPARED WITH APPLICABLE STANDARDS * Pollutants 600 MW Plant . Maxima 1200 MW Plant . Maxima U.S. ** NAAQS Montana AAQS Max. Allowable Increase (PSD) for Class II Area Canada Max. . Desirable Saskatchewan AAQS SO? 1 Hour 3 Hour 24 Hour Annual 214 96 28 2.4 428 192 56 4.8 - l300t 365 80 655 - 265 55 - 512 91 20 450 - 150 30 450 - 150 30 NO 1 Hour Annual 74 0.79 148 1.6 - 100 - - - - - 60 400 100 Particulates 2.6 0.2 5.2 0.4 l5O 75 200 75 37 19 - 60 120 70 24 Hour Annual Concentrations Assume Zero Percent Control; Particulate Concentrations Assume 99 Percent Control. MOS = Ambient Air Quality Standards. 1 Secondary Standard. ------- hour SO 2 concentrations, added to the background concentrations by a 1200 MW power plant, are about 56 pg/rn 3 . The total concentration of 82 pg/rn 3 is well below the Montana AAQS of 265 1.Jg/m 3 , and the NAAQS of 365 pg/rn 3 . The highest 1-hour concentrations are estimated to be near 428 pg/rn 3 for a 1200 MW plant. This concentration is below the 655 pg/rn 3 Montana AAQS but approaches the Canadian standard of 450 pg/rn 3 . Both the highest 3-hour concentrations and the annual concentrations are well below all air quality standards. Although the SO 2 concentrations resulting from a 1200 MW plant are below U.S. and Montana standards this will result in some deteri- oration of air quality in the U.S. impact area. To prevent significant deterioration of air quality the U.S. Clean Air Act prescribes a maxi- mum allowable increase in concentrations of SO 2 for Class II areas. These values are shown in Table 5.1—8. The maximum increases in SO 2 concentrations predicted for the impact area range from 24 to 62 per- cent of the maximum allowable increases. It should be emphasized that the preceding comparisons are based on the maximum predicted SO 2 concentrations. The predicted concentra- tions for most of the study area are considerably less than the maximum values. For example, the predicted annual SO 2 concentrations for most of Daniels County and all of Roosevelt County are about an order of magnitude less than the maximum values which occur near the Inter- national Boundary. Such low concentrations (0.2 pg/rn 3 for 600 MW, no control) are only about 1 percent of the Maximum Allowable Increase (PSD, Class II area). Moreover, it represents only about 0.4 percent of the Montana Ambient Air Quality Standards. Operation of a single 300 MW unit with no SO 2 control would result in predicted concentrations of one half of the preceding 600 MW values. A similar comparison can be made for short-term SO2 concentrations. The overall maximum 1-hour concentration of 96 pg/m 3 /600 MW, (no control) would occur at or near the International Boundary. Most of Daniels County would experience highest 3-hour SO 2 exposures of 20 to 40 pg/rn 3 , while maximum concentrations in Roosevelt and Sheridan Counties would be less than 20 pg/rn 3 . These values are quite low when compared with the National Ambient Air Quality Standard of 1300 pg/rn 3 . Furthermore, the maximum concentrations in Roosevelt and Sheridan Counties ( 3O pg/rn 3 ) represent only 6 percent of the maximum allowable increase for Class II areas. 5.1.5.2 NO Impact The predicted increase in NOx annual concentrations for a 1200 MW plant amount to only 1.6 pg/rn 3 . This is well below the 100 pq/m 3 NAAOS. The U.S. and the State of Montana do not have a 1-hour NOx standard. However, the Canadian 1-hour standard is 400 pg/rn 3 . The predicted highest NO 1-hour concentration in the impact area of 1L18 pg/rn 3 is well below the Canadian standard. 79 ------- 5.1.5.3 Particulate Impact The present particulate loading in the impact area has an annual geometric mean of about 20 to 25 ug/m 3 . A 1200 MW plant with 99 per- cent control will only add about 0.4 iJg/rn 3 to the present background concentrations. This is only about 2 percent of the maximum allow- able particulate increase permitted by the prevention of significant deterioration (PSD) regulations. The Montana and U.S. annual partic- ulate standards of 75 jg/m 3 would therefore not be exceeded in the impact area. The present 24—hour maximum particulate concentrations measured in the impact area by the Montana Air Quality Bureau range from 100 to 109 ug/m 3 . The predicted maximum increase of 5.2 ig/m 3 for a 1200 MW plant with 99 percent control would result in maximum 24-hour con- centrations of 105 to 115 g/m 3 . These values are below the Montana standard of 200 ug/m 3 and the U.S. secondary standard of 150 ig/m 3 . The predicted increase is about 14 percent of the maximum allowable increase under PSD regulations for Class II areas. The trace metal analyses of collector ash from Poplar River Coal were used in conjunction with model predictions to estimate potential elevations in atmospheric trace metal concentrations. The maximum annual increase in particulate concentrations was assumed to be about 0.1 pg/m 3 (600 MW plant with 99.5 percent ESP’s). Such concentrations could be expected to occur very near the International Boundary; how- ever, the annual particulate increases over most of the impact area would be approximately one order of magnitude less ( 0.01 iig/m 3 ) (Figure 5.1—7). The resultant predicted trace element concentrations are presented in Table 5.1-2. These values were then compared with background trace element concentrations measured by lesich and Taylor (1975) at Glasgow, Montana (Table 5.1—3). The comparisons indicate that operation of a 600 MW power plant would result in very minimal increases in background concentrations. The predicted annual increases range from 0.02 to 2.2 percent of the background levels (Table 5.1—2). These differences would not be detectable with air quality monitoring equipment. Even if the hi9hest 24-hour particulate concentrations were considered (1.0 Jg/mJ), the resultant increases over background would be only about 2 to 20 percent. Moreover, such increases would occur only at locations near the International Boundary. 5.1.5.4 Fumigation Impact The phenomenon known as “fumigation” is discussed in Appendix A-C Inversions. The CRSTER Model does not incorporate fumigation in esti- mating pollutant concentrations. However, Turner (1970) has suggested a method for estimating peak concentrations resulting from plume fumigation. Following this technique and employing the emission and 80 ------- Table 5.1-2 CALCULATED INCREASES IN AIR CONCENTRATIONS OF TRACE ELEMENTS NEAR THE POPLAR RIVER PLANT Maximum Increase 1 Percent Increase in Annual Concentration ( g/m 3 ) Above Background Antimony 9.8 x 1O 0.5 Arsenic 7.4 x 10 0.3 Beryllium 4.6 x io8 0.3 Cadmium 2.4 x io_8 0.05 Chromium 6.8 x io6 0.1 Copper 3.7 x 1O 0.2 —7 Germanium 1.8 x 10 1.4 Lead 1.6 x 10 0.3 Manganese 6.0 x 1O 2.2 Nickel 1.1 x i0 6 0.06 Selenium 2.9 x 1O 0.2 Silver 1.7 x io6 0.06 Vanadium 3.2 x io_6 0.4 Zinc 2.5 x io 6 0.02 1 Assuming atmospheric particulate concentration of 0.1 pg/rn 3 . 81 ------- Table 5.1—3 1975 BACKGROUND TRACE ELEMENT CONCENTRATIONS (1.ig/m 3 ) MEASURED NEAR GLASGOW, MONTANA Source: Mesich and Taylor, 1976. Composite Samples 2nd Quarter 3rd Quarter 4th Quarter Element Aluminum 1st Quarter 0.5 1.0 0.6 1.0 Antimony <6 x 1O 2 x 10 3 x 1O 3 x 1O Arsenic 2 x 1O 2 x 1O 3 x 1O 2 x 1O Beryllium <2 x 1O <2 x 1O <2 x 1O <6 x io6 Cadmium 2 x 10 3 x 1O 1 x 1O 3 x 1O Chromium 2 x 1O 9 x 1O 7 x 1O 2 x 1O Copper 3 x 1O 2 x 1o 2 3 x io 2 1 x io2 Germanium <5 x io 6 1 x 10 3 x 1O <6 x io 6 Lead 3 x 1O 9 x io 1 x io2 3 x io Manganese <4 x 1O <3 x 1O <3 x 1O 1 x 1O Nickel 2 x 1O 2 x 1O 5 x 1O <7 x 1O Selenium 2 x 1O 1 x 1O 2 x 1O 2 x 1O Silver 1 x 1O 5 x 1O 3 x 1O 2 x 1O Vanadium 4 x 1O 7 x 1O 2 x 1O 3 x 1O Zinc 4 x iü 1 x io 2 2 x io2 1 x io2 82 ------- stack parameters utilized in the CRSTER Model, concentrations were esti- mated for Pasquill stability categories E and F. The results are pre- sented in Table 5.1-4. For very stable conditions (CAT F) SO 2 concentrations of 2000 to 4000 pg/rn 3 may occur 10-20 kilometers downwind of a 1200 MW plant. Con- centrations of NO may range from 850 to 1350 pg/rn 3 , while particulate concentrations of 110 to 170 pg/rn 3 may occur. These concentrations are those that might occur when wind speeds are light and a very strong sur- face inversion is present. Furniaation concentrations under more typical meteorological condi- tions for Scobey, Montana are presented for the midseasonal months in Tables 5.1-5 throuqh 5.1—7. A summary of the meteorological conditions for these months and the height of the plume above the surface are pre- sented in Table 5.1-8. The meteorological conditions are based on upper-air temperature soundings and wind rose tables for Scobey, Montana. These data were presented and discussed by Gelhaus, et al. (1979). The plume heights were calculated using the Briggs’ (1969, 1970, 1972) plume rise equations. Both the plume heights and the inversion intensities ( T,’AZ) showed little seasonal variation. The plume heights were close to 200 meters, while the inversions were of moderate to strong intensity. The concentrations shown in Tables 5.1-5 through 5.1-7 are only one-half to one-third the values resulting from the more severe meteoro- logical conditions (Table 5.1-4). The highest concentrations occur in the winter with a minimum in the autumn. Also, concentrations decrease and the plume width increases with downwind distance. At 10 kilometers (krn) downwind from the source, the concentrations at a distance of 500 meters from the plume centerline are only 25 percent of those found at the centerline. At 20 km, the concentrations drop to 16 percent of centerline concentrations at a distance of 1000 meters fron the center- line. Wintertime SO 2 fumigation concentrations, along the plume center- line, range from 1800 pg/rn 3 at 10 km to 482 pg/rn 3 at 40 km for a 1200 MW plant. In the autumn, when the S02 concentrations may be the lowest, the values range from about 1100 pg/m 3 at 10 km to 298 pg/rn 3 at 40 km. The N0 wintertime concentrations along the plume centerline may range from 610 pg/rn 3 at 10 km to 162 pg/rn 3 at 40 km for a 1200 MW plant, (Table 5.1-6), while particulate concentrations may range from 76 pg/rn 3 to 20 pg/rn 3 at 10 and 40 km, respectively (Table 5.1-7). The frequency of plume fumigation will most l1kely be the greatest in the spring and summer and the lowest in the autumn and winter. Sta- ti sti cs on the frequency of stabi 11 ty categories dun ng the hours from 0000 to 0600 MST, presented by Gelhaus, et al. (1979) for Scobey, Montana, show that the F stability category (moderately stable) occurs about 25 to 30 percent of the time in autumn and winter and 35 to 45 percent in 83 ------- Table 5.1-4 ESTIMATES OF MAXIMUM GROUND-LEVEL CONCENTRATIONS (jiG/M 3 ) DURING MORNING FUMIGATION Downwind Stab Cat [ (Wind Speed 5 iii/s) Stab Cat F (Wind Speed 3 m/s) Distance (Kin) 600 MW 1200 MW 600 MW 1200 MW SO 2 NO x TSP SO 2 NO x TSP SO 2 NO x TSP SO 2 NO x TSP 10 804 270 34 1608 540 68 2016 676 85 4032 1352 170 15 634 213 27 1268 426 54 1571 527 66 3142 1054 132 20 508 171 21 1016 342 42 1301 436 55 2602 872 110 ------- Table 5.1-5 ESTIMATES OF MAXIMUM GROUND-LEVEL S02 CONCENTRATIONS (pG/M 3 ) DURING MORNING FUMIGATION RESULTING FROM TYPICAL METEOROLOGICAL CONDITIONS AT SCOBEY, MONTANA DOWNWIND DIST. (km) 600 MW JAN APR JUL OCT 1200 MW JAN APR JUL OCT Along Plume Centerline (CL) 10 20 30 40 912 863 822 568 484 457 434 301 321 303 288 195 241 227 216 149 1824 1726 1644 1136 968 914 868 602 642 606 576 390 482 454 432 298 500 m From CL 10 20 30 40 232 218 207 143 308 291 276 191 258 244 232 160 211 199 189 131 464 436 414 286 616 582 552 382 516 488 464 320 422 398 378 262 1000 m From CL 10 20 30 40 3.8 3.5 3.3 2.3 79.9 75.1 71.3 49.5 134 126 120 83.3 143 134 128 88.4 7.6 7.0 6.6 4.6 160 150 143 99.0 268 252 240 167 286 268 256 177 Note: Estimates are based on meteorological conditions shown in Table 5.1-8 with zero SO 2 control. ------- Table 5.1-6 ESTIMJ\TES OF MAXIMU 1 GROUND-LEVEL NOx CONCENTRATIONS (pG/M 3 DURING MOF NING FUMIGATION RESULTING FROM TYPICAL METEOROLOGICAL CONDITIONS AT SCOBEY, MONTANA DOWNWIND 01ST. (km) 600 MW JAN APR JUL OCT 1200 MW JAN APR JUL OCT Along Plume Centerline (CL) 10 20 30 40 306 290 276 191 162 153 146 101 108 102 96.6 65.4 80.8 76.2 72.5 50.0 612 580 552 382 324 306 292 202 216 204 193 131 162 152 145 100 500 m From CL 10 20 30 40 77.8 73.1 69.4 48.0 103 97.6 92.6 64.1 86.6 81.9 77.8 53.7 70.8 66.8 63.4 43.9 156 146 139 96.0 206 195 185 128.2 173 164 156 107 142 134 127 87.8 1000 m From CL 10 20 30 40 1.3 1.2 1.1 0.8 26.8 25.2 23.9 16.6 45.0 42.3 40.3 27.9 48.0 45.0 42.9 29.7 2.6 2.4 2.2 1.6 53.6 50.4 47.8 33.2 90.0 84.5 80.6 55.8 96.0 90.0 85.8 59.4 Note: Estimates are based on meterological conditions shown in Table 5.1-8. ------- Table 5.1-7 ESTIMATES OF MAXIMUM GROUND-LEVEL TOTAL SUSPENDED PARTICULATE (TSP) CONCENTRATIONS (jiG/M 3 ) DURING MORNING FUMIGATION RESULTING FROM TYPICAL METEOROLOGICAL CONDITIONS AT SCOBEY, MONTANA DOWNWIND DIST. (km) 600 MW JAN APR JUL OCT 1200 MW JAN APR JUL OCT Along Plume Centerline (CL) 10 20 30 40 38.2 36.2 34.5 23.8 20.3 19.2 18.2 12.6 13.5 12.7 12.1 8.2 10.1 9.5 9.1 6.3 76.4 72.4 69.0 47.6 40.6 38.4 36.4 25.2 27.0 25.4 24.2 16.4 20.2 19.0 18.2 12.6 500 m From CL 10 20 30 40 9.7 9.1 8.7 5.2 12.9 12.2 11.6 8.0 10.8 10.2 9.7 6.7 8.9 8.3 7.9 5.5 19.4 18.2 17.4 10.4 25.8 24.4 23.2 16.0 21.6 20.4 19.4 13.4 17.8 16.6 15.8 11.0 1000 m From CL 10 20 30 40 0.2 0.2 0.1 0.1 3.4 3.2 3.0 2.1 5.6 5.3 5.0 3.5 6.0 5.6 5.4 3.7 0.4 0.4 0.2 0.2 6.8 6.4 6.0 4.2 11.2 10.6 10.0 7.0 12.0 11.2 10.8 7.4 Note: Estimates are based on meterological conditions shown in Table 5.1-8 with 99.5 percent control. ------- Table 5.1-8 AVERAGE METEOROLOGICAL CONDITIONS (100-200 M LAYER) AND PLUME HEIGHTS DURING THE MORNING FOR THE MID-SEASONAL MONTHS AT SCOBEY, MONTANA PARAMETERS MONTH JAN APR JUL OCT T (°C) AT/AZ (°C/m) Pasquill Stability Category Wind Speed (mis) Plume Height (m) —17 2 12 2 0.013 0.017 0.018 0.016 F F F F 6.3 6.8 7.2 10.3 216 210 208 211 88 ------- the sprino and summer. Thus, the probability of local plume fumigations with concentrations of the magnitude shown in Tables 5.1-5 through 5.1-7 is relatively high. Fumigation events will result in high concentrations of SO2 within the impact area but they will be of short duration and confined to rela- tively small areas. While there are currently no national air quality standards (primary or secondary) for periods less than or equal to 1- hour, the potential exists for exceeding Montana’s 1-hour standard, which states that SO 2 concentrations shall not exceed 655 ug/m 3 for more than 1-hour in any four consecutive days. As indicated in Table 5.1-5, concentrations in excess of the state’s standard may occur in that area between 10 and 20 km from the emission source for the 600 MW facility and in that area less than 30 km from a 1200 MW plant during fumigation events. However, due to variable wind conditions and the fact that pre- dicted SO 2 concentrations at a distance of 500 m from the plume center- line are less than the state standards at all distances greater than or equal to 10 km from the emission source, it is improbable that excess 502 concentrations will occur for more than 1-hour during the specified time interval. - Since there are no short-term (<1 hour) state or national standards for NOx or particulates, there is no reasonable basis for comparison with predicted values. Potential effects of these constituents and SO2 will be discussed, however, in the vegetation impacts section (5.6.1). 5.1.5.5 Visibility Impacts Mathematical models describing the visual effects of power plant emission plumes are in the early stages of development. Recently, for example, a model has been developed to estimate the spatial and temporal distribution as well as the magnitude of visibility impairment resulting from power plant emissions of SO2 and NOx at various control levels (Latimer, 1980). Although the results of a generic application of this model for power plants in the West have been published, the generating capacity, meteorological and operating assumptions for the model plant were such that a comparison with the SPC power plant was not appropriate. Therefore, in the absence of suitable results, a quantitative estimate of visibility impairment in Montana resulting from emissions of the SPC power plant will not be provided. In qeneral, visibility impairment resulting from a coal-fired power plant may be classified into two types - short-range (<100 km) and long- range (>100 km). The short-range type, known as plume blight, occurs when a plume is perceptible because of its coloration. The long-range type, where the plume itself is not visible, results in regional haziness, and the visual range is reduced by plume aerosol. The short-range type generally results from NOx emissions. Nitrogen dioxide (N02) formed in the atmosphere from nitric oxide (NO) emissions is visible as a yellow 89 ------- or brown haze, particularly on mornings with stable, light-wind meteoro- logical conditions. The long-range type results from SO 2 emissions, which are slowly converted in the atmosphere into sulfate aerosol , which reduces visual range by contributing to regional haze. 5.1.5.6 Health Effects Epidemiological investigations have shown relationships between increased mortality and disease in populations exposed to elevated levels of atmospheric pollutants (National Academy of Sciences, 1975). The com- pounds primarily associated with health effects are sulfur oxide-particu- late complexes. These are formed by the combination of S02 gas and its conversion products (sulfuric acid and sulfate aerosols) with suspended particulate matter. The values presented in Table 5.1-9 provide an indication of the concentrations of atmospheric pollutants associated with health effects. Based on the projected levels of S02, NO and TSP associated with the operation of the proposed Canadian power plants, it is concluded that there will be no adverse health effects in populations residing within the Poplar River Basin. Table 5.1-9 EXPECTED HEALTH EFFECTS OF AIR POLLUTION ON SELECTED POPULATION GROUPS Value ( gJm ) Causing Effect Excess Mortality Worsening of Visibility and 1-lospital Patients with Respiratory and/or Human Pollutant Admissions Pulmonary Disease Symptoms Annoyance Elfc ts SO ° 500 (daily average) 500—250’ (daily average) 100 (annual anthmetic mean) 80 (annual geometric mean) 500 (daily average) 250 (daily average) 100 (annual arithmetic mean) 80 (annual geometric mean) ° British Standaid Practice (Ministry ot Technology. 19ô6) Values for sulfur dioxides and suspended partieulates apply onl’ ri conjunLtlon with each other They may have to be adjusted when translated into terms of results obtained by other procedrii es These values represent the differences ot opinion within the committee of experts Based on high-volume samplers Source: Shy, 1978 go ------- 5.2 WATER QUANTITY IMPACTS 5.2.1 Methodology 5.2.1.1 Flow Scenarios Flow impacts were assessed using predicted monthly flows for 1933- 1974 from the Karp II model of the Poplar River and the Modified Mon- treal Engineering (MME) model of Cookson Reservoir. Results are given at 12 stations (Figure 5.2-1). The Karp II Model was run for natural, historical, and existing conditions, six apportionment plans, unlimited Canadian uses, and two cases with ash lagoon decant. This section will discuss the impacts of the apportionment recommended by the Poplar River Task Force. The other apportionments will be discussed as alternatives. The natural flows were estimated using available flow data and interstation correlations to complete the flow record (Poplar River Task Force, 1976b). The historical water uses were then added to the ob- served flows to give the natural flows under predevelopment conditions with no apportionment. Historical flows were also estimated from avail- able flow data and interstation correlations (Poplar River Task Force, 1976b). The existing flows were developed for 1975 levels of develop- ment with the Cookson Reservoir but with no power plants in operation. The unlimited Canadian water uses scenarios allow all Canadian water to be used to represent a ‘worst case.’ The recommended apportionment splits the total natural flow of the Poplar River and tributaries at the International Border evenly between Canada and the U.S. In addition to this principal requirement the flow of the West Fork (stations 9 and 10) must be at least 50 percent of the natural flow and the flow of the Middle Fork (station 4) must be at least 60 percent of the natural flow. Flow in Cow and Coal Creeks (station 2 and 5) must also be at least 60 percent of the natural flow. Flow in the East Fork depends on the flow at station 4 because different size releases are made as shown in Table 5.2-1. If flow releases are needed to meet the apportionment, the releases are made from stations 2 and 5 first and station 4 second. 5.2.1.2 Model Description Flow scenarios with the recommended apportionment were run for five levels of development. The various scenarios used in analysis of im- pacts are summarized in Table 5.2-2. The scenarios 28 through 32 simula- tions included power plant evaporation but did not include decant from the ash lagoons as an inflow to Cookson Reservoir. Scenarios 4A, and 8A were simulated using the MME model to provide a “worst-case” where all the ash lagoon decant reaches Cookson Reservoir. Since the modeling work was done SPC has made plans to line the lagoons and recirculate the water instead of discharging the decant to Cookson Reservoir. The effect 91 ------- Figure 5.2—1 LOCATION OF STATIONS WITH FLOW RESULTS .i. .11 . :i I $ I $ ------- Table 5.2-1 RESERVOIR RELEASES ON THE EAST FORK OF THE POPLAR RIVER Flow at Station 4 Ac re-Feet Continuous Release Acre-Feet Months Demand Release Acre-Feet Months++ All year September-May June—August September-May June—August September-May June — Au gus t 300 May-September 500 May-September 500 May-September Sum of March through May flows at Middle Fork at border. ++Schedule for releases is based on irrigation need as follows: Month May June Percent 12 18 Amount of releases from scenario Environmental Sciences. 0-3,800 3,801—7 ,500 7,501—12,000 >12,000 60 60 120 120 180 120 180 1 ,000 May-September July August September 32 27 11 descriptions of Montana Health and 93 ------- Table 5.2-2 SUMMARY OF FLOW SCENARIOS Scenario No. Flow Type Level of Development No. of Power Plants 1 Natural Predevelopment 0 2 Historical Historical 1933—1974 0 3 Existing 1975 & Cookson Res. 0 28 Recomm. App 1975 1 29 Reconvn. App. 1985 2 30 Recomm. App. 1985 3 31 Recomm. App. 2000 3 32 Recomm. App. 2000 4 4A With Ash Lagoons 1975 1 8 With Ash Lagoons 1985 2 * Recommended Apportionment of Poplar River Task Force (1979). 94 ------- of the ash la oons is discussed in more detail in Section 5.3 Water Quality Impacts . A brief summary of the Karp II and MME models will be given here with a detailed discussion included in Appendix D. The Karp II model uses the estimated monthly natural flows and the esti- mated monthly flow at the East Fork border station from the reservoir model as input for the years 1933 to 1974. The net water uses discussed in the following section are subtracted from these flows corresponding to the appropriate scenario. Table E-2 in the Appendix gives the detailed uses and amounts of the surface and subsurface return flows. The output of the model is monthly flows for 1933 to 1974 for each of the 13 stations (see Figure 5.2-1). A cumulative frequency distribu- tion was computed and the flows exceeded 10, 50, and 90 percent of the time were listed in a summary section along with the mean flow. The MME model was used to simulate the Cookson Reservoir as affected by natural processes and operation of the coal mine and Canadian power plants. Inputs include tributary inflows, precipita- tion, natural and forced evaporation, inflows from ash lagoons, mine dewatering, releases, and groundwater seepage. The Cookson Reservoir was assumed to be full at the start of the simulation. The maximum reservoir volume was 32,550 ac-ft. The flow on the East Fork station at the border is determined from reservoir releases specified in the apportionment scenarios (see Table 5.2-1) and seepage from the ash lagoons and groundwater. 5.2.1.3 Water Uses Canadian Future Uses (1985 ) Except in the indicated cases, water use estimates of future uses for the model studies were taken from the International Souris - Red River Engineering Board, Poplar River Task Force, Appendix C (1976). These estimates are portrayed in Figures 5.2-2 through 5.2-4. (See Appendix Table E-4 for supporting values.) Municipal future uses were developed for the Village of Coronach based on inflated estimates of population levels due to anticipated in- creases due to development of coal deposits in the area. The expected increase cited by the Task Force was 114 ac-ft bringing the 1985 total usage to 150 ac-ft/year. If per capita consumption remains constant, this represents a population increase to 1250 persons in contrast to the 1975 population estimate of 300. At the year 2000 level, assuming constant per capita consumption, 5300 persons would be the projected population. The town of Rockglen derives its present water supply from groundwater and it was assumed that future increases could be met by that resource. 95 ------- 8.000 7 ,000 6,000 U 5,000 LU LU C 4,000 -j POPLAR IVI WATER USU z z LCGENO 3,000 I RlGAT$ON ] ESE VOIR IVAPO ATIQN 2.000 oo iu•ric 1.000 ______ WILOLtFE PC ER 0 PtANTS 1975 2000 LEVEL OF DEVELOP .1ENT Figure 5. -2 CANADIAN WATER USES Oi’ ih . LA 1985 96 ------- POPLAR !IVER WA1E USES LEGEND I IGATION REURVOI EVAPORATION E UNICZPAL DOrIESTIC WILOLIPE lift Figure 5.2-3 LEVEL OF DEVELOPMENT CANADIAN WATER USES ON THE MEDDLE FORK 2 U 2 LU LU 0 LU -J 2 z 8 ,000 7,000 6,000 5,000 4,000 3,000 2,000 1.000 0 1975 1985 2000 97 ------- 8,000 — 7,000 — 6.000 — U 5,000— Lu Lu C 4,000 — -J POPLAR RIVER WATER USIA z z LEGEND 3,000 — — IRRIGATION J RESERVOIR EVAPORATION 2,000 — OOIESTIC POWER ffl1ffl1 [ — PI.ANTS 1,000 — ______ 1975 1985 2000 LEVEL OF DEVELOPMENT Figure 5.2-4 CANADIAN WATER USES ON THE WEST FORK 98 ------- Future industrial uses are also predicted primarily on the develop- ment of coal resources in the area. Water requirements in 1985 would include 3,600 ac-ft for natural evaporation due to installation of a reservoir for coal-fired power plants. Installation of two power plants would require an additional 2180 ac-ft for forced evaporation and plant consumptive uses. These figures are taken from Volume One of the Poplar River Final Environmental Assessment for Saskatchewan Power Corporation (Saskmont Engineering, 1978). Forced evaporation was calculated on the basis of a 5.2°C temperature excess above normal lake water temperature for two 300 MW power plants. Using this excess and other meteorological data daily evaporation was calculated as follows: E = b(T - Td) f (U) where E is the daily evaporation (Btu Ft 2 Day 1 ) b = .255 - .0085 T + .00024 T 2 and - T = (T 5 + Td) / 2 T = water surface temperature Td = dew point temperature f(U) is a windspeed function equal to 70 + 0.7 U 2 where U is the wind speed in miles per hour. Losses due to an increase in thermal loading were computed as — b(K - 15.7 ) HP dE— (0.26+b) R where dE is the increase in evaporation (Btu Ft 2 Day ) HP is the thermal loading and K is the coefficient of surface heat exchange equal to 15.7 + (0.26 + b) f(U) and b and f(U) are as previously defined. The volume of water evapo- rated was then evaluated by making use of the latent heat of evaporation of water (about 1032 Btu/lb). Wildlife uses were estimated at 300 ac-ft/year and divided equally between the East and Middle Forks. These uses were estimated in 1985 by Ducks Unlimited to be 1,220 ac-ft. The 300 ac-ft fiqure was derived as a result of considering that only 25 percent of the projects would be implemented. 99 ------- Domestic uses were estimated based on linear extrapolations of historical domestic water usage increases. The Task Force predicted a 1985 use of 730 ac-ft. There is a discrepancy between this and Table E-4 in that the total domestic 1985 use is only 708 ac-ft. The differ- ence is the usage in other small tributaries crossing the International Boundary. The uses were proportioned among the three forks based on the same percent as the 1975 percent of the total. The Poplar River Task Force report indicated irrigation water usage by private developers to be 380 ac-ft by 1985. Altogether, based on linear extrapolation of historical growth rates, the increase was ex- pected to be 120 ac-ft over the 1975 level of 300 ac-ft. The 120 ac-ft was proportioned among the three forks in the same way that domestic uses were. In addition, an irrigation project amounting to 100 ac-ft was planned for the West Poplar, bringing the 1985 total irrigation usage to 520 ac-ft. Canadian Future Uses (2000 ) All irrigation development presumed to occur was expected to have taken place by 1985. No further development was estimated for the year 2000. The construction of a reservoir for power plant development accounts for the additional 4960 ac-ft of reservoir evaporation loss from the Middle Fork. This was computed similarly to the reservoir evaporation losses under the 1985 level of usage. The 1181 ac-ft of forced evaporation and plant consumptive use was also predicted as per the 1985 levels. From a water balance, 1827 ac-ft of water diverted from the West Fork was deemed necessary to allow for power plant devel- opment on the Middle Fork. Municipal water uses for the Village of Coronach were estimated as 500 ac-ft over the 1985 level of consumption for a total of 650 ac- ft. To meet this demand an additional source of water is required and it was assumed that 333 ac-ft would be diverted from the Middle Fork to the East Fork for this purpose. Domestic (stock-watering) and wildlife demands were not expected to increase past the 1985 levels. United States Future Uses The estimates of future uses in the U.S. portion of the basin are shown in Figures 5.2-5 through 5.2-9 (see Appendix Table E-5). The municipal demands that were used in modeling studies were assumed to be exclusively by the Town of Scobey, Montana. Projections for the future population estimates based on historic trends were made by the Montana Department of National Resources and Conservation. 100 ------- 8.000 POPLAR RIVER WATER USES LEGS ND IRRIGATION MUNICIPAL [ J OO IIE ST1C Figure 5.2-5 U.S. WATER USES ON THE EAST FORK OF THE POPLAR RIVER 7 000 6 000 C., 5.000 4,000 -J z 2 3.000 2.000 1.000 0 1975 19C5 2000 LEVEL OF DEVELOPMENT 101 ------- 8.000 — 7.000 — 6.000 — U 4 5,000 — 4,000 — POPtAR RIVER WATER I. E5 2 2 4 LEGEND 3,000 — IRRIGATION _ //// / OOHESIIC 2.000 1,000 — 0—— — 1975 1905 2000 LEVEL OF DEVELOPMENT Figure 5.2-6 U.S. WATER USES ON THE MIDDLE FORK OF THE POPLAR RIVER ABOVE THE CONFLUENCE WITH EAST FORK 102 ------- 8.000 1975 1985 2000 LEVEL OF DEVELOPMENT POPLAR RIVER WA lER USES LEGEP D IRRIGATION DOINSTIC — Figure 5.2—7 U.S. WATER USES ON WEST FORK OF THE POPLAR RIVER (INCLUDES INDIAN AND NON-INDIAN USES) U 4 I- z LU LU a LU -J 4 2 2 4 7.000 6,000 5,000 4,000 3,000 2.000 1,000 0 103 ------- 8,000 — 7.000 — 6,000— w U 5,000 — 4,000— _______________ P P1 .AR P.WER WATER !S UGEND 3,000 — — IRRIOAION 2.000— OO?IEETIC 1,000 — 0— — 1975 1985 2000 LEVEL OF DEVELOPMENT Note: West Fork uses are excluded. Figure 5.2-8 U.S. WATER USES ON MAIN STEM OF POPLAR RI’/ER ABOVE FORT PECK INDIAN RESERVATION AND BELOW CONFLUENCE OF MIDDLE AND EAST FORKS 104 ------- 70,000 1975 1985 2000 Figure 5.2-9 LEVEL OF DEVELOPMENT U.S. WATER USES ON MAIN STEM OF POPLAR RIVER WITHIN FORT PECK INDIAN RESERVAT ION 60,000 U 2 LU LU C LU -I 2 2 50.000 40,000 30,000 2,000 1,000 POPI.AA RIVER WATER USES LEGEND IRRIGATION OO? ESTIC 0 105 ------- In the past 15 years the population of Scobey has decreased steadily. The 1985 projection is 1445 persons. Water use per capita has increased but was assumed to level off at 250 gal/day. Using this per capita usage and the 1985 population estimate the value of 400 ac-ft in the table was derived. The development of a potash facility was expected to reverse the population trend by the year 2000 and bring it to 2160 persons. Using the same per capita usage the 600 ac-ft figure was obtained. The model diverted the water for Scobey from station 3 but the wells are located just below the confluence with the Middle Fork. Stock and domestic water requirements for the non-Indian lands were estimated by the Montana Department of Natural Resources and Conserva- tion for 1985 and 2000. They were based on linear extrapolation of the 1931-1975 trends. The numbers include stock uses and stock pond evapo- ration. The Montana DNRC also made projections of the number of irrigated acres for each of the West, East and Middle Forks (non-Indian portions) based on linear extrapolations of 1960 through 1975 data for spreader dike irrigation systems. (The acreage estimates for all types of irri- gation systems appear in Appendix Table E-3.) These systems were assumed to require a single 10 inch (.833 ft) application per year. Multiplying the projected acreages by this figure the requirements for these sub-basins were obtained. The spreader acreages for the Indian lands were assumed to remain the same as the 1975 levels through 1985 and 2000. Using the same 0.833 irrigation depth requirement, the total requirements for Indian lands were calculated. For the West Fork, the Indian and non-Indian land requirements were summed. This sum appears in Table E-5. For the Lower Poplar the indicated value is the product of estimated Indian spreader acreage and the irrigation depth alone. Acreage projections for flood irrigation and sprinkler irrigation were also estimated with regression techniques by the Montana DNRC. Data from the period of 1961 through 1975 were used. Morrison-Maierle, Inc. (1978) estimated that the flood irrigation acreages would remain constant for the Indian lands through 2000. Estimates of seasonal diversion requirements by the Montana Health and Environmental Sciences Department, Water Quality Bureau, were 39 inches/acre for flood irri- gation and 29 inches/acre for sprinkler irrigation. Sprinkler irrigation acreages on Indian lands were expected to increase drastically due to the availability of water from the con- struction of two large reservoirs. The seasonal requirement for sprinkler irrigation operations was based on the requirements for alfalfa grown on class II lands. This requirement is roughly 18.5 inches/acre. Assuming a 65 percent field and conveyance efficiency about 29 inches/acre need to be diverted. Multiplying this by the total acreage in sprinkler irrigation for each sub-basin and converting inches to feet gives the volumes shown in Table E—5. Although the Morrison-Maierle report (1978) indicates the need for a much larger consumptive use per acre and hence a larger diversion volume, similar depth requirements were used for the entire basin (see next section). Water applications were made between May and September according to percentages given in Appendix Table E-1. 106 ------- Domestic and stock water demands for Indian lands also include both livestock uses and evaporation from stock ponds. The substantial increase in the 1985 and 2000 figures over the 802 ac-ft of 1975 is due to the expected installation of the two reservoirs indicated above and resultant evaporation from them. Their combined storage is 152,400 ac-ft and their combined surface area is about 7700 acres. The annual evaporation from these large reservoirs is 4924 ac-ft. Including the 802 ac-ft from existing stock consumption and evaporation, the total domestic and livestock requirement tallies to 5726 ac-ft.’ Discussion of Irrigation Requirements In the majority of cases, estimates for future water requirements from different sources who had performed analyses of the Poplar River system were supportive. Occasionally, the sources were not in agree- ment. This was the case in the determination of irrigation water re- quirements on the Fort Peck Reservation. Estimates of the water require- ment for alfalfa were derived using a modified Blaney-Criddle approach and were calculated at 33 inches. Subtracting annual precipitation and dividing by a 63 percent combined field and conveyance efficiency gave a seasonal estimate of 34.9 inches or 2.9 ac—ft (Morrison-Maierle, 1978). Tetra Tech calculates the water requirement for alfalfa as follows. Alfalfa can be grown from the first frost-free day of spring to the last frost-free day in fall. The Climatic Atlas of the U.S. gives these dates as May 30 to roughly September 20. From Figure 4.5-2 the total potential evaporation for June through September is 21.5 inches. Multiplying by the upper limit of the Blaney-Criddle evapotranspiration coefficient (Schwab, etal., 1966) the consumptive use for alfalfa would be 18.3 in- ches. Subtracting the June through September normal precipitation depth of 6.5 inches gives a net requirement of 11.8 inches. Dividing by the field and conveyance efficiency of 63 percent gives a gross diversion recuirement of 18.7 inches per acre. This is roughly half of the Morrison-Maierle estimate. Agricultural irrigation design, however, is predicated upon risk. While evapotranspiration will not vary widely from year to year, pre- cipitation can vary greatly. Cumulative precipitation probabilities for Havre, MT were used (Dept of Commerce, 1968). The April through Sep- tember normal precipitation for Havre and the Poplar River Basin (taken from Glasgow, Montana) is similar (8.5 inches). The cumulative proba- bility curve shows that 90 percent of the time a rainfall depth of 5.4 inches (April through September) will be equalled or exceeded. This means that there is a 10 percent change that less than 5.4 inches will fall. Adjusting this value for only June through September by the ‘Montana Health and Environmental Sciences Department, 1979. 107 ------- ratio 6.5/8.5 we can estimate that there is a 10 percent chance of receiving less than 4.1 inches during the alfalfa growing season. In- corporating this into the design, the consumptive use of 18.3 inches would be decreased by 4.1 inches of precipitation. The difference divided by the efficiency of 63 percent gives 22.5 inches. Demand for this quantity of water should only be exceeded on the average once every ten years. This appears to be a realistic design quantity for alfalfa. Most other crops grown in the area would require less water with the possible exception of sugar beets. Based on these estimates it appears that values for irrigation volumes predicted by the Soil Conservation Service approach are more reasonable than those made by other sources. The estimate made by Tetra Tech is lower than those made by other sources due to the fact that April and May are not considered as part of the irrigation season. Even if ambient temperatures during these months are conducive to plant growth it is doubtful that large quantities of irrigation would be re- quired since snowmelt conditions would tend to keep the soils at mois- ture contents suitable for plants at least for portions of these months. 5.2.2 Predicted Flows Pertinent results discussed here are the flows under scenarios 1, 2, 3, 28, 29, 30, 31, and 32 (see Table 5.2.2). Scenarios 28-32 use the apportionment whereby the U.S. receives 50 percent of the natural flow of the West Fork, 60 percent in the Middle Fork and reservoir re- leases as scheduled in Apportionment VI in the East Fork (see Table 5.2-1). Monthly flows in the Poplar River were calculated for the 10, 50, and 90 percent frequency for the scenarios listed above with develop- ment (i.e., irrigation, municipal use, domestic use) at the commensurate levels. The percentages associated with each are the chance that flows will be less than the flows represented in the figures. For instance, in the first plot (Figure 5.2-10) there is a 90 percent chance that the flow at the International Boundary on the East Fork in April will be less than 15,941 ac-ft under scenario 28. The flows at each station at the 10 and 90 percent frequency are tabulated in the Appendix (Tables F—i and F-2). 5.2.2.1 Flow Conditions at the 90 Percent Level Monthly flows at the International Boundary on the East Fork are shown in Figure 5.2-10. The change from scenario 1 to scenario 3 in- volves the installation of Cookson Reservoir. Essentially only the spring peak flows have been affected under scenario 3. Spring flood peaks are primarily the result of snowmelt. The runoff in 1975 was high so the flows are only decreased by 13 percent. The addition of power plants to the system has the effect of drawing the storage in the 108 ------- 20,000 16000 12,000 8,000 4,000 C 0 w U 0 0) 2 0 I — U) JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Figure 5.2-10 FLOWS AT EAST FORK OF POPLAR RIVER AT INTERNATIONAL BORDER ------- reservoir down and thereby decreasing the spillage during peak periods. The model predicts that the spring runoff flows will occur in March or April as occurs under natural conditions. The spring runoff flows oc- curred in May and June at station 1 (USGS, 1976, 1977) in 76—77 after construction of the reservoir. The summer flows are less under the apportionment conditions than natural conditions. The percent reduction from scenario 1 to scenario 28 during 1ay is 44 percent. The percent reduction from scenario 1 to scenario 29 is 53 percent. Scenario 30 and 31 bring about a 65 percent reduction and scenario 32 causes an 80 percent reduction from scenario 1. In June all scenarios bring about a 63 percent reduction in the natural flows. In July the natural flows are reduced by 35 percent for all scenarios and in August the demand release flows under all scenarios are the same as the natural flows. Winter flows are higher under the apportionment scenarios than natural or historical flows. Basically, the same patterns that exist under the different scenarios at the Inter- national Boundary on the East Fork also are manifested in the flows on the East Fork near Scobey (Figure 5.2-11). The flows on the Middle Fork at the International Boundary (Figure 5.2-12) are 60 percent of the natural flows for all scenarios under Apportionment VI except scenario 32. Until a storage reservoir is con- structed on the Middle Fork above the border as predicted by year 2000, the actual flows will be close to those under natural conditions since only 188 ac-ft is used annually in 1975 and 396 ac-ft in 1985. In the Main Poplar at the boundary of the Fort Peck Reservation (station 8), flow reductions increase with increasing levels of develop- ment. Figure 5.2-13 shows that in 90 percent of the years the flow in August and September went to zero under the year 2000 level of develop- ment. During the other summer months, the flows were reduced from 20 to 50 percent of the natural flows. The flows in the West Poplar (station 9 — Figure 5.2-14) under Apportionment VI are specified as 50 percent of the natural flew. Thus, all scenarios (28-32) have the same flow at the International Boundary. At Poplar, Montana on the Main Poplar (station 12 - Figure 5.2-15), with the exception of scenario 28 all future use scenarios have flows that are zero in the months October through February due to construction of two reservoirs on the reservation. Scenarios 31 and 32 also have zero flows in March 90 percent of the time. During the spring, flow reductions are greater as the level of development increases. 5.2.2.2 Flow Conditions at the 10 Percent Level On the East Fork at the International Boundary the effect of in- stalling Cookson Reservoir is seen by comparing scenarios 1 and 3. Flows generally are damped out in the spring through storage. Ground- water seepage increases flows in October through March. Flows for sce- narios 28-32 are representative of the demand releases from the reser- voir (Figure 5.2-16). The changes in flow will impact the downstream 110 ------- 28,000 C 0 U- a ’ ‘I I— a I— . I— ’ 0 ) 0 4 I- 12,000 4,000 A A - .—-—- —. JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV FLOWS AT EAST FORK OF POPLAR RIVER AT SCOBEY DEC Figure 5.2—11 ------- 20 OO0 16,000 12,000 8 000 4,000 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Figure 5.2-12 FLOWS AT MIDDLE FORK OF POPLAR RIVER AT INTERNATIONAL BORDER ------- 60000 50,000 40000 ‘C C a U- 30,000 0 z 0 I- I- 20000 10,000 - Sd 0—————•O Sc28 •Sc29 ___ — •Sc30 p OSc3l •—————. Sc32 JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Figure 5.2-13 FLOWS OF MAIN POPLAR RIVER AT FORT PECK INDIAN RESERVATION ------- 8000 6000 C 0 U C 4000 0 2.000 - S d o—————-o Sc28 SL2O ___ - •Sc30 p Sc31 .—————. Sc32 JAN FEB MAR APR MAY JUL AUG Figure 5.2-14 FLOWS OF WEST POPLAR AT THE INTERNATIONAL BORDER ------- 120 000 A A __—___ 0 —o C 0 w U 0 z 0 I- U, 100 000 80 000 60 000 40000 20 000 JAN FEB MAR APR MAY FLOWS OF POPLAR RIVER AT POPLAR Figure 5.2-15 ------- - S d •Sc3 p pSc28 Sc3O p pSc3l - 0 .. fl 0 0 U 0 z 0 4 (I ) SAOOQ / JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC FLOWS AT EAST FORK AT INTERNATIONAL BORDER Figure 5.2-16 ------- fish and wildlife populations during the spring. The flows in March are expected to be 52 to 63 percent less, 19 to 88 percent less in April, and 30 to 51 percent less in May with the recommended apportion- ment under 1975 levels of development and one 300 MWe unit operating. With four 300 MWe units operating and year 2000 levels of development the flow decreases in March, April , and May are 63 to 98, 69 to 88, and 42 to 80 percent, respectively. The drop in spring flows are shown in Figures 5.2-17 and 18. In the East Fork near Scobey the flows are capable of meeting water requirements under all scenarios during the months of May and June. Under scenarios 31 and 32 flows are zero in March, April, July, August, and September (see Figure F-i in Appendix). In March, however, histori- cal flows are also zero 10 percent of the time. During all other months the flows are adequate to meet the demands with the scheduled releases. On the Middle Poplar at the International Boundary the zero flows for future uses coincide with the zero flows under the natural conditions. April peak runoff is reduced on the order of 26 to 29 percent under fu- ture uses (see Figure F-2 in Appendix). Flows on the Main Poplar at the Fort Peck Reservation boundary are zero in March and June through September (see Figure F-3 in Appendix). In the West Fork at the International Boundary, flows under sce- narios 28 through 32 will be zero for all months. Natural flows are zero 10 percent of the time for all months except May, October and No- vember (see Figure F-4 in Appendix). The flow of the Main Poplar at Poplar will be zero for all months under scenarios 29 through 32 depending on the operating schedule of the proposed reservoirs (see Figure F-S in Appendix). Under scenario 28, flows will be adequate to meet demands in all months except March, July, August and September. 5.2.3 Direct Impacts 5.2.3.1 Municipal Water Supply The only municipal uses of Poplar River water are for Scobey. The town operates several wells close to the river which receive a large percentage of their recharge from the river. The model used a conser- vative approach in that all the water is withdrawn from the river at station 3 with no return flow. However, the wells are actually located below the confluence with the Middle Fork so recharge would come partly from the Middle Fork. The municipal demand varies by month as shown below depending on need for outdoor water: 117 ------- I I I I I I I 1 1 1. 1,1 1 1 I i i I I I .. i . . I n_I MARCH STATION I - EAST S March Sd .. MaichSc3 _______________ March Sc28 1940 1950 Figure 5.2-17 1960 1070 MARCH FLOWS ON THE EAST FORK 1933-1974 100,000 - 10000- 1 , 0 0i) - 100 — 10 - a U 4 ------- 100.000— I ii ii I I i i. •iii I Ii 19 0 1060 1970 APRIL STATION 1 - EAST t April Sd o_____.- ApnISc3 April Sc28 APRIL FLOWS ON THE EAST FORK 1933-1974 10,000— 1,000 — 100— 10 - 1940 Figure 5.2—18 ------- Monthly Demand, ac-ft/month January July Total 1975 14 56 350 1985 16 64 400 2000 24 96 600 Ten percent of the time or one in ten years the flows in March in the East Fork at Scobey are zero under existing (post-reservoir), his- torical , and the recommended apportionment. The water uses in March (1975) were estimated as 789 ac-ft for spreader irrigation, 105 ac-ft for stock and 17.5 ac-ft for municipal water supply. The available water before diversions is estimated as 56.7 ac-ft (from model results at stations 1 and 2). Thus, the municipal demand could be met with an addit 4 onal 39.2 ac-ft left over which could be used for instream uses, stock or irrigation. The municipal demand for March is expected to in- crease to 20 ac-ft in 1985 and 30 ac-ft in 2000. Thus, the water avail- able for irrigation would decrease to 36.7 and 26.7 ac-ft which would supply about 44 and 32 acres, respectively. The model overestimated the impact since an additional 24.3 ac-ft and 8.1 ac-ft of water would be available from the Middle Fork in 1985 and 2000, respectively. Flow in April is adequate under 1975 and 1985 levels of development but not for year 2000 uses. The municipal demand would be 36 ac-ft. This demand could be met out of the estimated available water of 56.7 ac-ft leaving 20 ac-ft for other demands including stock and spreader irrigation. Flows in August and September were adequate to meet demands for 1975 and 1985 but not for year 2000. The water uses for year 2000 are estimated as follows: Uses August September Flood Irrigation 146.4 62.7 acre-feet Municipal 90 60 Available Water 56.7 56.7 The municipal demands are higher in these months reflecting outdoor uses for a total of 250 gallons per capita/day. If the basic water supply needs of 30 ac-ft were met 26.7 ac-ft would be available for irrigation. The municipal demands can be met in the other months. The inability to meet the high summer demands could be resolved by drilling another well away from the river or encouraging the public to conserve water. Some water could come from the Middle Fork although flows are zero 50 percent of the time for historical and existing conditions. In some years flows have also been zero on the East Fork at Scobey in late summer. 120 ------- 5.2.3.2 Uses Dependent on Spring Runoff Spring runoff peak flows are expected to decrease under the appor- tionment plan at all the border stations but will decrease the most on the East Fork (see Figures F-6, F-7, F-8 and F-9 in Appendix). The peak flows supply water for filling stock reservoirs and irrigating land by the spreader method. The peak flows also scour the river chan- nel and clean out sediment deposited under low flow conditions. This scouring function is important in maintaining fish and wildlife habitat as will be discussed in more detail in Section 5.6.4. Model output gives the volume of discharge in ac-ft rather than a peak discharge in cfs. Flow data for two years since the Cookson Res- ervoir was constructed provide an indication of what daily peak flows might be on the East Fork. The flows in March, 1976, reached a maximum of 827 cfs. The peak flows in the 76-77 water year came in May with peak flows of only 58 cfs. The peak flows in the 77-78 water year in May were 270 cfs. The variability of peak flows occurs also under natural conditions (see Figures 5.2-13 and 5.2-14). Water demands on the East Fork between stations 1 and 3 include 789 ac-ft for spreader irrigation and 105 ac-ft for stock. One year out of ten the full demands cannot be met in 1975, 1985, or 2000. If the maximum amount was used for irrigation in 1975 about 47 acres could be irrigated instead of the total of 1,023 acres. The lack of adequate supplies for irrigation and filling stock reservoirs in March is less serious if adequate flows occurred in April or May. In four of the nine years with zero flows in March the main runoff came in April. In the other five years of low spring runoff most of the runoff occurred in March. The water available in April for these uses and instream flows is adequate in 1975 and 1985 but not year 2000. The available water would be 20 ac-ft which would not meet the total projected demand of 816.2 ac-ft. These low flows occurred in five out of 43 years when all but one year had a low spring runoff. March flows on the main Poplar (station 8) are zero 10 percent of the time for historical and existing conditions and the recommended apportionment. This is not surprising since flows at station 3 further upstream at Scobey are also zero 10 percent of the time. Available water from the Middle Fork varies between 8 and 24.7 ac-ft for the rec- ommended apportionment. The demands for water at station 8 include 334 to 465 ac—ft for stock/domestic uses and 287.6 to 816.8 ac-ft for spreader irrigation. These demands appear to be high since the esti- mated natural flow was only 186 ac-ft 10 percent of the time. However, stock reservoirs are filled mostly from smaller tributaries to the main forks of the Poplar River whenever the spring runoff occurs. Prior to construction of two reservoirs on the Fort Peck Indian Reservation March flows at Poplar (station 12) are zero 10 percent of the time under historical, existing and the recommended apportionment conditions. Thus, the spreader irrigation demand of 228.8 ac-ft would 121 ------- not be met 10 percent of the time. April flows would be zero 10 per- cent of the time in 1985 and 2000 but no diversions are required al- though there would be impacts on fish and wildlife. The water needed for stock and sprinkler irrigation is estimated as 33,384 ac-ft in 1985 and 61,042 ac-ft in 2000. Available water flowing into the reservoirs in dry years (one out of ten years) from October through March would be about 2,000 ac-ft in 1985 and 1,652 ac-ft in 2000. The stock and domes- tic demand of 802 ac-ft could be met and 1,199 and 850 ac-ft would be available for irrigation in 1985 and 2000, respectively. This amount could supply 450 acres in 1985 and 319 acres in 2000. Stock and spreader irrigation demands can be met at the Lower Middle Fork (station 7) and Lower West Fork (station 11). Flows at the Upper West Fork (station 9) are zero in March and April under natural, historical , and the recommended apportionment conditions one year out of ten but there are no diversions for water uses. 5.2.3.3 Summer Flows Summer flows are diverted for flood and sprinkler irrigation. The model distributed the demand according to the monthly schedule shown in Tables E-1 and E-2 in the Appendix. The estimated actual and projected acreages under irrigation were compared to the number of acres which could be irrigated with the available water based on four applications per year with an average of 6.1 inches per month. The information will be summarized below with the complete table included in the Appendix (Table F-i). This is a worst case since the average number of appli- cations per year has been 2.4 under historical conditions with little or no irrigation in August and September. Irrigation demands on the Upper East Fork can be met from a quantity standpoint in 1975 and 1985 at least 90 percent of the time. The demand for irrigation of 1,533 acres in the year 2000 exceeds the available supply in August and September. Flows have been zero 10 percent of the time under historical and existing conditions. The number of acres that could be irrigated in these months is about 188 depending on the method and extent of municipal uses. Flows in the upper Middle Fork (station 4) are zero in August and September, an estimated one out of ten years, for the recommended apportionment as well as for natural and existing conditions but there are no diversions. Flows in the Lower Middle Fork (station 7) are zero 10 percent of the time in June for the historical, existing, and apportionment condi- tions. The rest of the summer can be even drier with flows zero 50 per- cent of the time in July and 90 percent of the time in September under existing and apportionment conditions. Irrigation demands (net) are as follows: 122 ------- 1975 2000 June 381.1 acre—feet 674.2 acre—feet July 522.4 1051.7 August 412.8 833.5 September 137.6 280.6 Only a part of this demand could be met at the ten percent frequency even under natural conditions when only 194.4 (June), 32.4 (July), and 8 ac-ft (August and September) would be available. Fewer irrigation applications under 1975 conditions would be made since only 408 acres could be irrigated in June, 344 in July, 36 in August and none in September. The full irrigation demand could be met in June more than 50 percent of the time but less than 50 percent of the time in July and less than 10 percent of the time in August and September. During the summer months of June to September flows on the Main Poplar (station 8) are zero one out of ten years under the recomended apportionment and historical and existing conditions. For the year 2000 level of development the flows for August and September are zero in 40 out of 42 years. Water demand in June for irrigation in 1975 was 472.9 ac-ft. This is estimated to increase to 810.9 ac-ft by the year 2000 which is more than the 640 ac-ft under natural conditions. Available water would provide about half of the 1975 demand and could irrigate about 708 acres depending on the type of crop and irrigation method used. For the year 2000 the available water could irrigate about 440 acres. Irrigation demand in July was 718 ac-ft in 1975 and is projected to increase to 1248 ac-ft in the year 2000. Under the recommended apportionment the number of acres which could be irrigated averages 492 in 1975 and 24 in 2000. The available water is much less than the net irrigation demand of 560.7 ac-ft in 1975 and 982.3 ac-ft in 2000. The response of farmers in dry years such as these would most likely be not to irrigate the third and fourth time. The case in September is similar with a net irrigation demand of 199.8 ac-ft in 1975 and 322.5 ac-ft in 2000. The number of acres which could be irrigated is 172 in 1975 and 148 in 1985. Flows on the Upper West Fork (station 9) are zero ten percent of the time under historical, existing, and the recommended apportionment conditions in March, April, August, and September. No diversions are made from the river at station 9. As expected, flows in the Lower West Fork (station 11) are zero in August and September under historical existing and the recommended apportionment. By the year 2000 May and June flows are estimated to be zero 10 percent of the time. Water uses for irrigation include 356.2 ac-ft in May and 582.8 ac—ft in June in 2000. These demands cannot be met 10 percent of the time since there is no available water from upstream. Full irrigation demands in July 123 ------- cannot be met 50 percent of the time in 1985 and 2000, with water avail- able in 1985 to irrigate only about 24 acres. August and September flows are zero 10 percent of the time under historical , existing and the apportionment scenarios and 50 percent of the time for the recom- mended apportionment scenario. For September in the year 2000 the flow is zero 100 percent of the time if maximum available water was with- drawn. The irrigation demands are as follows: August September 1975 204.2 acre-feet 70.2 acre-feet 2000 725.3 246.1 Water would be available to meet these demands less than 50 percent of the time. The water available less than 10 percent of the time could irrigate about 48 acres. Meeting the 1975 irrigation demands during the summer on the Fort Peck Indian Reservation is possible 50 percent of the time. The full demand can be met 10 percent of the time in June and September. In July only about 296 acres can be irrigated instead of 618 acres. In August no water is available for irrigation. Expansion of irrigation is projected based on construction of two reservoirs on the Main Poplar. The design capacity of these reservoirs is 152,400 ac-ft (Morris-Maierle, 1978). After construction of the reservoirs the projected demand in 1985 for 10,618 acres can be met at least 50 percent of the time. The irrigation demand in 2000 for 20,618 acres cannot be met 50 percent of the time if no carryover storage from wet years is included. The full irrigation demand can be met if carry- over storage from one year is included or irrigation is delayed until May. The releases below the two new reservoirs are needed for flood irrigation. Flows in May and June are adequate to meet demands in 1975 but not in 1985 and 2000 at least 10 percent of the time. Water used for flood irrigation is estimated to be 39 ac-ft in May and 64.3 ac-ft in June. Flows in July and August are zero under historical , existing, and the recommended apportionment 10 percent of the time so the flood irrigation demands of 99.7 ac-ft in July and 78.7 ac-ft in August would not be met. The September water demand of 26.2 ac-ft for flood irriga- tion could be met in 1975 but not in 1985 or 2000 at least 10 percent of the time. Water could be made available if small releases were made in the sumer during the low-flow years. 1 2â ------- 5.2.3.4 Winter Flows Winter flows are needed to maintain the fish and wildlife habitat. The upper reaches of the Poplar River can freeze and so have no flow. The no flow conditions occur under natural and the recommended apportion- ment scenarios at stations 2, 4, 5, 9 and 10 in one out of ten years. Flows are zero under natural conditions only at stations 1, 3, 6 and 7. Flows in the Lower Main Poplar (station 12) would be zero after con- struction of the reservoirs in 1985 if no releases are made. The Upper West Fork winter flows (station 9) (December to February) are zero for all years under natural and all other conditions. In November under the recommended apportionment the flows are zero 90 percent of the time. The lack of flow in the winter partly explains the poor fish habitat. The winter conditions on the Upper Middle Fork (station 4) are similar with zero flows 50 percent of the time. 125 ------- 5.3 WATER QUALITY IMPACTS 5.3.1 Description of Quality Models llater quality in the Poplar River was simulated using Karp III and the Modified Montreal Engineering (MME) model of the Cookson Reservoir. Appendix D includes a detailed description of both of these models. The quality at border, Poplar Reservoir, and downstream stations was modeled differently. The basic method was to develop regression equations for specific conductivity or total dissolved solids (TDS) based on the aver- age monthly discharge. Regression equations were then developed to predict sodium, sulfate, boron, and hardness concentrations from TDS. At downstream stations a mass-balance approach is used. The water qual- ity is calculated from the quality of upstream water plus any ground- water seepage, irrigation return flow, or runoff. Average yearly groundwater quality and seepage flows were used for each station. The quality of surface irrigation return flow was calculated at 10 percent higher than the quality of the diverted water due to evaporation and salt pickup. A hypothetical reservoir on the Middle Fork of the Poplar River in Canada was included in the year 2000 scenarios to meet Canadian water demands. The quality in this reservoir was based on mass-balance of all inflows and outflows and complete mixing in the reservoir. The quality of the outflow was calculated as the average of the reservoir quality at the beginning and end of the month. After construction of the Poplar Reservoir water is released from this reservoir if needed to meet the flow apportionment rather than Cookson Reservoir. The Cookson Reservoir was simulated by the MME model (described in Saskmont Engineering, 1978). The model input includes natural and forced evaporation, tributary inflows, direct precipitation, ash lagoon discharges, mine dewatering discharges, power plant releases, and groundwater seepage. Overflows from Fife Lake occurred in March through October of 1952-54. The model includes power plant operations such as addition of sulfuric acid for reverse osmosis treatment of boiler feed- water, demineralization, and chlorination of condenser cooling water. The effects on the ash lagoons of these processes are modeled for each lagoon as if it were a separate reservoir. The outflow from the ash lagoons is partly surface flow to the reservoir and about 30 ac-ft/month of subsurface flow into the East Fork between the dam and the border. Additional groundwater seepage also flows into this section of the river and is included in the computation of water quality at the border. The outflow quality from the reservoir is determined by complete mixing of the reservoir and mass balance of all reservoir inflows and outflows. The appropriate releases are made with the quality equal to the result- ing quality of the reservoir at the end of the month. The quality at the East Fork border station is used as input for the river quality model, Karp III. The MME model was used for scenarios 4A and 8A. Sce- narios 28 throuqh 32 include forced evaporation but not the ash lagoon inflow to Cookson Reservoir. 126 ------- Using model results a discussion is presented below regarding effects of power plant operation and apportionment on criteria and stan- dards associated with irrigation stock watering, and human consumption uses. Effects on aquatic life and secondary impacts on agricultural land use are discussed in Sections 5.6.3 and 5.5, respectively. Figure 4.6-1 shows points where projected water quality simulation results are available. In terms of irrigation and stock watering uses, as well as impacts of power plant operation, the stations of interest are 1, 3, 8, and 12. For potable water supply use, stations 3 and 7 are important. This is the case because the Town of Scobey draws its water from the East Fork (below the confluence with the Middle Fork) and the Town of Poplar uses groundwater. The remainder of the system, while having altered flows, will have only nominally altered quality. For purposes of the primary impacts discussion, modeling scenarios 2 and 3 and 28 through 32 are considered. It is important here to note the following: scenario 2 represents historical, pre-Cookson Reservoir conditions. Scenario 3 represents 1975 conditions with Cookson Reser- voir in-place. Scenario 28 represents 1975 conditions with a single operating power plant. Scenarios 29 and 30 represent projected 1985 conditions with two and three power plants, respectively. Scenarios 31 and 32 represent year 2000 conditions with three power plants and four power plants, respectively. Scenarios 4A and 8A with one and two plants, respectively, are also discussed. 5.3.2 Boron Plants can be sensitive to boron but trace amounts are required. Thus, concentrations in water used for irrigation are important. The months during which most irrigation occurs in the Poplar River Basin are April through September, inclusive. The impacts of the increased boron concentrations are discussed both for scenarios 28 through 32 which do not include the ash decant and scenarios 4A and 8A which do. The con- centrations at stations 1, 3, 8, and 12 are discussed for both types of scenarios. Summary tables of model output are included in Appendix G. The impacts of these concentrations on crops (alfalfa, barley, oats, and wheat) and livestock are discussed next. Boron concentrations decrease in the downstream direction as shown in Figure 5.3-1. Scenarios 28, 29, and 31 represent the more likely cases. All boron concentrations for stations 1, 3, 8, and 12 are below 3 mg/2. for scenarios 28 and 29. Boron concentrations for scenario 31 at stations 1 and 3 are less than 4 mg/2 during the irrigation season but have a 10 percent probability of exceeding 4.1 mg/i. during the winter. For the four power plant case (scenario 32) boron concentrations at station 1 during the irrigation season may range between 0.4 and 0.8 mg/9. at the 10 percent probability level and between 3.8 and 8.0 mg/Z at the 90 percent probability level. The boron concentrations for scenario 32 at the other stations were less than 4 mg/9. during the irri- gation season, although winter concentrations at station 3 were up to 6.3 mg/2. at the 90 percent probability level. 127 ------- 8 KEY: r 10T090 PERCENT 1. PROBABILITY LEVEL (ppI) — Sc 28,5OppI 6 sc 29,9OppI Sc. 31, 9OppI I— Sc 32, 9OppI STATION WHERE MODEL Al OUTPUT AVAILABLE o 2 o —j- .- o z - O 2 — . —-. 00 2’5 50 7’5 Al h3 8 A 12ft APPROXIMATE DISTANCE DOWNSTREAM OF INTERNATIONAL BORDER, miles Figure 5.3-1 BORON CONCENTRATIONS IN JULY ON EAST FORK AND MAIN STEM OF POPLAR RIVER FOR SCENARIOS 28, 29, 31, AND 32 ------- Boron concentrations are higher when the ash decant is included (scenarios 4A and 8A) (Figure 5.3-2). The resultant concentrations during the irrigation season are discussed for stations 1, 3, 8, and 12. The concentrations at station 1 with one power plant are between 3.7 mg/ at the 10 percent probability level and 7.5 mg/2. at the 90 percent probability level during the irrigation season. With two power plants the concentrations increase at station 1 for the same probability levels above to 3.6 mg/L and 13.9 mg/2.. At station 3 the concentrations for the one power plant case range between 1.1 mg/2 . at the 10 percent proba- bility level and 6.5 mg/.Q at the 90 percent probability level and between 1.0 and 11.4 ma/9 . for the two power plant case. Concentrations at sta- tion 8 exceed 4 mg/2 .. only for the two power plant case at the 90 percent probability level. Concentrations at station 12 are below 4 mg/L at all probability levels. 5.3.2.1 Boron Impacts on Crops The effects of boron toxicity in crop-soil systems is poorly defined partly because the soil-water-plant system is so complex and variable. Experimental data are sparse and are collected under a variety of soil and climatic conditions. Soil chemical data were available at a limited number of locations, mostly adjacent to the Poplar River and only a few water quality parameters were modeled. For these reasons the crop yield changes presented here should be considered as best estimates for compara- tive purposes only. The crops studied were alfalfa, wheat, barley, and oats, although at present the latter two crops are not usually irrigated. These crops were included since it is important to determine if the diversity of crops grown could be limited by future water quality. Compared to salinity and sodicity few studies have been performed relating to boron toxicity. Only three studies were found that related boron (B) in the soil solution or irrigation water to the yield of alfalfa, wheat, barley or oats. Eaton (1944) grew alfalfa, barley, and oats using irrigation water with boron concentrations ranging from a trace to 25 mg- B/2,. Fox (1968) showed that calcium treatments had no effect on alfalfa grown with boron concentrations in the nutrient solution ranging from 0.25 to 32 mg-B/2 . Yields, on the average, decreased with the increas- ing boron concentrations. Chauhan and Powar (1978) had decreasing wheat yields when boron concentrations in the irrigation water increased from 0.5 to 8 mg-B/2.. Other work done by Hatcher, etal. (1959) showed that plants respond to soluble boron in the soil solution and not to that adsorbed or held in mineral complexes. Whei irrigation waters containing boron are applied to soils some of the boron is adsorbed. Therefore it is difficult to determine the amount of boron that the plant is actually responding to. In the experiment of Chauhan and Powar (1978) the soil solution concen- tration of boron was measured. At low concentrations of added boron the soil solution concentration exceeded the concentration in the irrigation water. However at high concentrations of added boron the solution con- centration was only half the concentration in the irrigation water. Eaton (1944) and Fox (1968) only measured the boron concentration in the 129 ------- 14 KEY T 10 TO 90 PERCENT I PROBABILITY LEVEL (ppl) — SC.4A,5Oppl SC. 8A, 9OppI — — sc. 8A,5OppI S — S S S S. APPROXIMATE DISTANCE DOWNSTREAM OF INTERNATIONAL BORDER, miles Figure 5.3-2 BORON CONCENTRATIONS IN JULY ON EAST FORK AND MAIN STEM OF POPLAR RIVER FOR SCENARIOS 4A AND 8A S. 5 ’ 5’ S. S. 5’ 5’ 5’ S. 12 l0• . 5 5 ’ 5 ’ 5’ 5’ S. 5’ S. S. S. E 0. z 0 I— F- z U 0 0 0 z 0 0 aD 6 . 5. -. 5 .- \ 4 \ 2 Al A3 8â I2 ------- irrigation water therefore their data are subject to some interpretation since some boron may be adsorbed by the soil and is not available directly to the plant. Boron adsorption is discussed in more detail in Appendix G. The approach used to estimate the effect of boron on crop yields was to develop regression equations between the boron concentration in the soil solution and the percent yield using data from the literature. Al- falfa appears to be the most boron tolerant of the four crops based on the projection of the regression line to zero yield (see Figures G-1 through G—4 in Appendix G). The zero yield projection for alfalfa is 41.3 mg-B/9 (soil solution) followed by oats (13.1), wheat (12.3) and barley (11.4). The regression equations for percent yield of these crops with mg-B/9 . (soil solution) as the independent variable are: Percent Alfalfa Yield* = 88.9 - 2.15 B (r = -0.56) Percent Oats Yield = 75.1 - 5.7 B (r = -0.78) Percent Wheat Yield = 105.7 - 8.71 B (r = -0.95) Percent Barley Yield = 86.6 - 7.61 B (r = -0.91) *Note: In reality zero boron concentrations would not result in maximum yield since trace amounts are required. The data for the Poplar River Basin were obtained in the following manner. Average properties were estimated from available data (Horpestad, 1978) for the soils in the East Fork sub-basin above the Fort Peck Indian Reservation and within the reservation. Boron concentrations in the irrigation water were averaged over the period April through September for stations 1 and 3 for the East Fork sub-basin and stations 8 and 12 for the Fort Peck Reservation at the 90, 50, and 10 percent cumulative probability level for scenarios 4A, 8A, 28, and 29. Boron concentration in the soil solution was estimated by an equilibrium approach using Langmuir adsorption constants (for details see Appendix G). The dilu- ting effect of growing season precipitation was then accounted for at the 90, 50, and 10 percent probability levels. The dilution factor was determined using precipitation from the three closest weather stations to Scobey for which April to September probabilities have been tabulated (Thomas and Whiting, 1977) Havre, Montana, Billings, Montana, and Williston, North Dakota. Distances from Scobey to these stations were determined and inverse distance weights for these stations were used to calculate precipitation values for the 90 percent, 50 percent and 10 percent probability levels at Scobey. These values are 14.2, 10.5 and 7.0 inches, respectively. The seasonal water requirement for alfalfa (from June to September, assuming that in the months of April and May the soil will retain sufficient moisture from snowmelt, requiring no irrigation) is 18.5 inches. This number is computed by using potential evaporation for June to September and multi- plying by the upper limit of the Blaney-Criddle consumptive use factor (0.85) (Schwab, etal., 1966). Subtracting the 90, 50, and 10 percent probability rainfall magnitudes from the total consumptive use require- ment give the 90, 50, and 10 percent irrigation requirements for this crop of 4.3, 8.5, and 11.5 inches, respectively. 131 ------- Similarly irrigation requirements for oats, wheat and barley (ex- pected irrigation season from May through July) can be determined. The dilution factor can be calculated for these crops at each rainfall probability level (Table 5.3-1). Multiplication of the boron concen- tration in the soil (Be) by the dilution factor gives a reasonable seasonal average concentration to which the plants respond. In the analyses which follow it is assumed that the distribution of rainfall and distribution of water quality parameters are independent. This assumption becomes more favorable as impoundments are constructed in the basin. The expected changes in yield from those yields which would occur in the upper basin (East Fork) and within the Ft. Peck Reservation if these crops were presently being irrigated were computed for the four crops. The changes were derived by taking the average boron (water soluble) content of the soils from existing data and entering the yield functions to estimate a present percent yield. The Be for scenarios 4A, 8A, 28, and 29 were then computed and the rainfall dilution factors applied. These concentrations were used in the yield functions and the differences between these yields and present yields computed. The changes in yield were also estimated for the combined effects of boron, salinity, and sodicity. These results are discussed following the section on salinity and sodicity effects. The present yields for 1975 for alfalfa, wheat, barley and oats due to soil boron are estimated to be 87 percent, 97 percent, 79 per- cent and 70 percent of the optimum for the East Fork sub-basin and 84 percent, 85 percent, 69 percent and 62 percent within the Fort Peck Reservation, respectively. These present yields are based on the aver- age chemical composition of the soil saturation extract and no moisture stress. The projected yield reductions due to boron are less than the projected reductions due to salinity. The greatest yield reductions for scenarios 4A and 8A due to boron were as follows: Crop Percent Yield Reduction From Present Yield Alfalfa 6 Wheat 27 Barley 24 Oats 18 Reductions were greater for the two power plant case (scenario 8A) in the East Fork sub—basin but almost equal in the Fort Peck Reservation. Yield increases for alfalfa, barley, wheat and oats were predicted for scenarios 28 and 29 but boron inputs from the ash lagoons were not included. The expected yields are similar for the East Fork sub-basin and the Fork Peck Reservation, although present yields in the Fort Peck Reservation appear lower. Expected yields were the same for the one and two power plant cases. 132 ------- Table 5.3-1 IRRIGATION REQUIREMENTS AND DILUTION FACTORS FOR ALFALFA AND SMALL GRAINS Crop Rainfall Probability Level 90% 50% 10% DF* IR+ DF JR DF IR Alfalfa Small grains .23 .43 4.3 6.7 .46 .58 8.5 9.0 .62 .72 11.5 11.2 * DF = Dilution Factor, dimensionless +IR = Irrigation Requirements, inches 133 ------- 5.3.2.2 Other Boron Impacts With respect to stock watering boron probably is of little conse- quence. Boron fed to the dairy cow as boric acid at the rate of 16-20 g/d for 40 days had no ill effects ( Water Quality Criteria , 1972). Even at 4 mg/Z of boron, this represents about 220 gallons per day, or more than seven times what milk cows consume and about 21 times what beef cattle consume (“Water-use in Montana”, Montana DNRC Inventory Series Report 13, 1975. A suggested limit for livestock was 5 mg/2. although this was based on the maximum concentration found in a survey of lakes and rivers and not on specific effects of boron ( Water Quality Criteria , 1972). The limit was not included in the 1976 update Quality Criteria for Water . Boron concentrations at stations 1 and 3 exceed 5 mg/9. for part of the year at the 50 and 90 percent probability levels for scenarios 4A and 8A. Boron concentrations at station 8 exceed 5 mg/2. in February with one power plant and in four additional months with two power plants at the 90 percent probability level. Concentrations at station 12 do not exceed 5 mg/9 for either scenarios 4A or 8A. Boron concentrations exceed 5 nig/2.. for some months at station 1 only if four power plants were operating (scenario 32) without the ash decant input. There is no drinking water standard for boron. The highest boron concentrations without the ash input to the Cookson Reservoir at the 90 percent probability level are 4.1 mg/9 . with up to three power plants and 8 mg/9. with four power plants and year 2000 level of development. With all the ash decant entering the Cookson Reservoir the concentrations may reach 20 mg/2 . at station 1 at the 90 percent probability level. Con- centrations of 5 to 20 g of boric acid (one-time ingestion) may cause death in adults (Stecher, P.G., 1968). The concentrations in the East Fork are considerably less than this and the concentration in the water supply would be even smaller due to adsorption as the water moved through the soil to the well and due to dilution by the Middle Fork and ground water. 5.3.3 Salinity and Sodicity The salinity and sodicity of the river are higher in August and September than June as shown in Table 5.3-2. The highest concentrations at all stations occur in the winter (see Appendix G). SAR (sodium ad- sorption ratio) is not a true conservative parameter so actual downstream values are higher than given by the model. These parameters and sulfate can be used to classify irrigation water (Klarich, 1978) as shown below: Salinity as Water SO 4 TDS Class SAR ( mg/2 .) ( mg/2 . ) I <1.0 - 4.2 <192 - 480 <700 II 1.0 - 11.6 192 - 960 350 - 2100 III >9.0 - 11.6 >576 - 960 >2100 - 3000 134 ------- Table 5.3-2 SALINITY, SAR, AND SO 4 CONCENTRATIONS AT SELECTED STATIONS Stations Scenarios* Salinity (TDS), mg/i. SAR June Sept SO 4 , mg/2 . June Sept June Sept 1 3 4A 28 844 1099 946 907 1285 1028 4.5 4.6 5.3 5.6 4.8 4.9 229 244 354 439 260 284 3 3 4A 28 827 1095 884 950 1277 988 5.0 5.7 5.4 5.8 5.1 5.8 226 268 336 415 240 279 8 3 4A 28 918 974 935 1087 1189 1087 6.1 7.1 6.0 6.6 6.1 7.1 248 324 275 367 264 321 12 3 4A 28 1147 1135 1147 1367 1364 1367 8.7 9.5 8.7 8.8 8.7 9.4 242 293 242 306 242 243 Values shown give concentration which is exceeded only 10 percent of the time. Monthly tables at the 10, 50, and 90 percent probability levels are included in Appendix G. *Scenarios are defined as follows: 3 = existing conditions with Cookson Reservoir but no power plants, 4A = 1975 development with one power plant and ash lagoon input, 28 = 1975 development with one power plant and no ash lagoon input. 135 ------- Based on this classification system, the river water at stations 3, 8, and 12 would be considered class II for scenarios 28 through 32, 4A and 8A and for historical (scenario 2) and 1975 conditions (scenario 3). The water at station 1 would be class II for scenarios 2, 3, 28 through 31, 4A and 8A; class I for scenario 28 at the 10 and 50 percent proba- bility level and class II at the 90 percent probability level; and class III for scenario 32. 5.3.3.1 Salinity and Sodicity Impacts on Crops The effects of salinity on crops are considered to be primarily osmotic. Plants respond to the total ion content of the soil solution as well as to specific ions. In this investigation the electrical con- ductivity of the saturation extract (ECse) has been used to determine the osmotic stress on plants due to salt buildup in the soil profile. The symptoms of salinity poisoning to crops are retarded growth as evidenced by fewer plants with smaller and fewer leaves (Rhoades, 1972). Sodium, however, has not only a toxic effect but also damages soil structure reducing permeability. High concentrations of a single ion, such as sodium, also may upset the competitive uptake of other bene- ficial nutrients (Kamphorst and Bolt, 1976). The sodium absorption ratio (SAR) is the water quality index with which the sodicity hazard has been estimated. It is a measure of the availability of the monovalent sodium ion to the availability of the beneficial calcium and magnesium divalent species. The SAR values used are for the soil saturation extract as calculated in Appendix A. The exchangeable sodium percentage (ESP) has also been used as an index of sodicity (Chang and Dregne, 1955; Bains, etal., 1970; Agarwala, etal., 1964). The SAR is used in this investigation because it is consistent with Gapon’s equation (Sposito and Mattigod, 1977) and the Poisson-Boltzman equation (Bower, 1961) for double layer exchange. Numerous studies have been done to determine the effects of salin- ity and sodicity (Table 5.3.3) including one study by Werkhoven (1964) in which he grew alfalfa and wheat on three loam soils from southeastern Saskatchewan. Several studies also investigated the effect of leaching fraction on the salinity and sodicity hazard. Additional information on the salt and sodium tolerance of these agricultural crops can be found in Biggar and Fireman (1960), Agarwala, etal. (1964), Wahhab (1961), Bernstein, etal. (1974), Hanks, etal. (1977), and Shourbagy and Wallace (1965). Methodology for Estimating Crop Yields From most of the literature surveyed on salinity and sodicity it is unclear whether the decrease in crop yield is a result of an increase in SAR or conductivity in the soil solution since in most cases they 136 ------- Table 5.3—3 AVAILABLE STUDIES ON SALINITY AND SODICITY HAZARDS Reference Bernstein and Pearson (1956) Chang and Dregne (1955) Chang (1961) Werkhoven (1964) Bower, Ogata and Tucker (1968) Bower, Ogata and Tucker (1969) Bernstein and Francois (1973) Ingvalson, Rhoades and Page (1976) Ayers, Brown and Wadleigh (1952) Mehrotra and Gangwar (1964) Asana and Kale (1965) Torres and Bingham (1973) Elgabaly (1955) Bains, etal. (1970) Hassan, etal. (1970) Patel and Dastane (1971) Number of Leaching Soil Types Fractions Used Pachappa loam, Chino clay Gila clay loam Gila loam 6 SE Saskatchewan soil types Pachappa sandy loam Pachappa sandy loam Pachappa sandy loam Pachappa fine sandy loam Pachappa fine sandy loam 6 Indian soils Indian soil sand culture resin sand culture sandy loam Hobbs silt loam several types +Crop types are A = alfalfa, W = wheat, B = barley, and 0 = oats. + Crops A,W,B,O A A A,W A A A A W,B W,B,0 W W B B B B 1 1 1 1 4 >1 >1 1 1 1 1 1 1 1 1 4 137 ------- vary coincidentally. The two variables are related best to percent yield using the following function: f(SAR, EC)se = in (SAR x EC)se where SAR is computed with Na+, Ca 2 +, Mg2+ expressed in meq/2., EC has units of pmho/cm, and the subscript se stands for saturation extract measurement. The yield data from each experiment were reduced to rela- tive yield by dividing each yield by the maximum yield for each soil type. These percent yield data were then plotted against the corres- ponding f (SAR, EC)se value for each crop. Each crop responded similarly as shown in the plots (Appendix G). At an f (SAR, EC)se value of approx- imately 1.5 yield reduction began to become evident and decreased approx- imately linearly. Below this threshold value, yields were consistently around 100 percent. At some very low values of the function, barley, wheat and especially oats seemed to experience ion “starvation”. Relative yield functions were obtained from linear regression on the “declining yield” portion of the plots. The functions are as follows: Percent Alfalfa Yield = 100% for x < 1.7 and = 129.81 - 17.41 (x), x > 1.7 (r = -0.71) Percent Wheat Yield = 100% for x < 0.4 and = 105.12 — 11.75 x, x > 0.4 (r = -0.62) Percent Barley Yield = 100% for x < 1.5 and = 126.15 - 17.22 x, x > 1.5 (r = —0.75) Percent Oat Yield = 100% for x < 1.8 and = 153.55 - 29.38 x, x > 1.8 (r = -0.95) where x = in (SAR) EC)se in all the above equations. 138 ------- Based on these empirical relationships it appears that oats have the highest threshold tolerance for SAR and EC of the saturation extract but are also most sensitive to increments of the two (having the high- est slope). Wheat apparently has the lowest threshold tolerance and is least sensitive to incremental increases in SAR 5 e and ECse. Alfalfa and barley appear to be almost equally tolerant. The average soil properties and dilution factors were estimated as described in section 5.3.2.1 Boron Impacts. The soil chemical data (Table 5.3-4) show that the soils within the Fort Peck Reservation are more nutrient enriched. The quality of irrigation waters applied to these soils was tabulated at the 90, 50, and 10 percent probability level. The steady-state values of ECse and SAR 5 e resulting from appli- cation of irrigation water to these soils for three leaching fractions (0.1, 0.2, and 0.3) were then computed as a seasonal average for April through September. These are the values of EC and SAR to which the plants would respond. The derivation of the ECse values from the TDS and SAR of the irrigation water using the method of Kamphorst and Bolt (1976) is described in Appendix G. Yield Changes The present yields relative to optimum of alfalfa, wheat, barley, and oats due to salinity and sodicity of the soil are estimated to be 91, 79, 89, and 88 percent for the East Fork sub-basin and 90, 78, 86, and 86 percent for the Fort Peck Reservation, respectively. These yields are based on the average chemical composition of the soil satu- ration extract and no moisture stress. The maximum yield reductions due to salinity for scenarios 4A and 8A were as follows: Crop Percent Yield Reduction From Present Yield Alfalfa 48 Wheat 35 Barley 51 Oats 87 Additional irrigation water applied to the soil removes or leaches the salts built up by evaporation and thus decreases the salinity of the soil. For example, a leaching fraction of 0.1 indicates that 10 per- cent more water is applied than required by the crop. The yield re- ductions are significantly less with a leaching fraction of 0.2 instead of 0.1. The improvement in yield with a leaching fraction of 0.3 is most pronounced for the poorer irrigation water quality at the 90 per- cent probability level, as would be expected. The improvement with a leaching fraction of 0.3 is small for the other probability levels. 139 ------- Table 5.3 4 AVERAGE CHEMICAL DATA FOR UPPER BASIN SOILS AND SOILS WITHIN FT. PECK B Ca Mg K Na CEC pH EC e SAR e Location mg/L nieq/100 g - mno/cm (meq/ ) Upoer Basin (U.S. portion) 11.7 37.7 16.4 - 141.2 ll 79 1.9 4.8 Ft. Peck Reservation 1.6 60.0 63.0 170. 255. 29 8.1 1.8 5.5 +Estinlated value The yield reductions were also estimated for the scenarios without the ash decant - 28 (1975 with one power plant) and 29 (1985 with two power plants). The maximum reductions which occur for scenario 29 for leaching fractions of 0.1 and 0.3 are as follows: Crop Percent Yield Reduction From Present Yields Alfalfa 39 ( 7)* Iheat 30 ( 8) Barley 41 (14) Oats 75 (25) * Values in parenthesis are for a leaching fraction of 0.3. Under high rainfall conditions and the median water quality conditions with a leaching fraction of 0.1 yield increases in alfalfa due to lower salinity and SAR values may occur in both the East Fork sub-basin and the Fort Peck Reservation. When the leaching fraction is increased to 0.2 yield increases for alfalfa also may occur under the median rain- fall conditions. Yield increases for barley, wheat, and oats may occur with a leaching fraction of 0.2 under high rainfall and median water quality conditions and under the median rainfall with water quality conditions at the 10 percent probability level. The change from one to two power plants results in yield decreases generally of zero to 2 per- cent with a maximum of 5 percent. 140 ------- 5.3.3.2 Impact on Crops of Combined Effects of Salinity, Sodicity, and Boron The effects of boron and salinity/sodicity were considered to be additive. The yield reductions were computed for scenarios 4A, 8A, 28 and 29. Summary tables are included in Appendix G. Since the SAR values from the model are low, the yield reductions for the Fort Peck Indian Reservation could be greater. Scenarios 4A and 8A will be discussed first. For alfalfa grown in the East Fork sub-basin yield reductions of up to 50 percent may occur with a leaching fraction of 0.1 in low rainfall years. Yield increases can occur when the leaching fraction is increased to 0.2 under certain rainfall and water quality conditions. In general, yield reductions within the Fort Peck Reservation for alfalfa would be less. The increased reduction due to the addition of two power plants is 2 to 8 percent in the East Fork sub-basin and zero to 1 percent in the Fort Peck Reservation. Yield reductions of up to 60 percent are possible for wheat for a leaching fraction of 0.1 and generally seem greater than for alfalfa in the East Fork. Within the Fort Peck Reservation yield reductions for wheat are estimated to be less than those for alfalfa. Barley yield reductions are estimated to be up to 75 percent in the East Fork. Yield reductions within the Fort Peck Reservation are about 5 percent less than for alfalfa. Oats were shown to be the most sensitive crop from the salinity standpoint and with low rainfall and leaching fraction of 0.1 no crop would be produced if irrigated. Severe yield reductions of up to 60 percent would also be realized in the Fort Peck Reservation. The yield decreases for scenarios 28 and 29 without the ash decant are less than for scenarios 4A and 8A. The maximum yield decreases in low rainfall years with a leaching fraction of 0.1 are as follows: Crop Percent Yield Reduction From Present Yield Alfalfa 38 Wheat 28 Oats 74 Barley 42 These yield reductions are 20 to 30 percent less than for scenarios 4A and 8A. Yield increases may occur at high leaching fractions in years with at least the median rainfall for all crops. Oats could be irri- gated under all conditions although the yields were estimated to be low. The change from one to two power plants results in yield decreases between zero to 9 percent. 141 ------- 5.3.3.3 Other Salinity Impacts TDS concentrations exceed the recommended limit for drinking water of 500 mg/i (EPA, 1977) at stations 3 and 7 for all scenarios including historical conditions during all but a few winter months at the 10 per- cent probability level. Waters containing in excess of about 1300 mg/i TDS may be considered unacceptable by consumers. TDS concentrations above 1300 mg/i were projected at station 3 for scenarios 29 through 32 and 8A at the 90 percent probability level. Diluting flow from the Middle Fork is available only in the spring and winter except in high rainfall years. TDS concentrations above 3000 mg/i can cause effects in poultry. Concentrations exceed 3000 mg/i for scenario 32 in the winter at the 90 percent probability level at stations 1 and 3 but not for any other scenarios. All concentrations are below 5000 mg/i so would be suitable for livestock. 5.3.4 Sulfate (SO 4 ) Secondary Drinking Water Standards (EPA, 1977) for SO 4 have been established at 250 mg/i. This is due to the fact that SO 4 , when present in potable water in high concentrations or when in moderate concentra- tions and consumed by individuals unaccustomed to it, may have a laxa- tive effect. The water quality modeling results (Appendix G) indicate that the SO 4 standard for drinking is exceeded on a historical basis about 10 percent of the time during low-flow months (August-March) in the Lower East Fork near Scobey (Appendix Table G.2-3). Under the apportionment agreement and with up to two power plant units in operation (1985), the standard would be exceeded 10 percent of the time every month. However, the maximum 90 percentile concentration under scenario 29 is 383 mg/i (during January) and 386 mg/i for scenario 2. The standard would be ex- ceeded 50 percent of the time for scenarios 4A and 8A with a maximum 90 percent concentration of 665 mg/i for station 3 and 280 mg/i for station 7. Operation of three or four units at 1985 or 2000 level of develop- ment would result in significant SO 4 elevations. With four units (i.e., scenario 32) the drinking water standard would be exceeded at least 50 percent of the time during low-flow months. Maximum concentrations occurring at a frequency of 10 percent during low-flow months would ex- ceed 800 mg/i. Sulfate is also an important water quality constituent in relation to agricultural uses. Sulfate concentrations are an indication of poten- tial salinity and may also be directly toxic to plants at concentrations greater than 500 mg/i. Sulfate ion concentrations at all stations gener- ally increase both with increasing numbers of power plants on the reservoir and with increasing irrigation development. Concentrations tend to remain relatively constant as the irrigation season progresses in the East Fork whereas they tend to increase during the summer at the 142 ------- lower stations on the main stem of the Poplar. The only time when levels are unacceptable in the system are at the International Boundary in March under scenarios 30 through 32 and 8A at the 90 percent proba- bility level. Therefore, sulfate ion concentration does not appear to be a crucial factor to consider with regard to suitability of waters for irrigation. 5.3.5 Mitigative Measures to Reduce Impacts of Saline Irrigation Waters Due to the high potential for increased salinity of Poplar River waters following power plant developnent and associated apportionment agreements between the U.S. and Canada, it is appropriate to discuss potential mitigative measures. High salinity water used for irrigation may have two potential impacts: • Direct salinity damage to irrigated crops. • Downstream effects on a variety of water uses due to highly saline irrigation return flows. In arid regions, when rainfall is less than 20 inches/year, little leaching occurs and the alkalinity of the soils remains high. Normally a layer with higher levels of caustic calcium carbonate than the sur- rounding material can be found; the lower the rainfall , the closer this layer is to the surface. Poplar River Basin soils have a pH ranging from about 7.5 to 8.5 making them midly alkaline. Soils with pH in this range, having high soluble salt concentrations, can have detrimen- tal effects on plants due to plasmolysis. That is, concentration grad- ients tend to move water out of plant tissues into the soil until plant cells collapse. Irrigation with saline waters aggravates this situation. Irrigation appears to be the practice which will dominate agricul- tural water consumptive use in the Poplar River Basin in the future. Irrigatton can be extremely beneficial to the economy of the basin. However, if improperly managed, it can have detrimental effects. Over- irrigating can cause mineral salts to be leached from the soils and introduced into shallow ground water aquifers which recharge the river, impairing water quality downstream. Downstream impacts include not only problems of saline waters for municipalities and stock watering operations, but also for other irrigators who, in turn, must irrigate their crops with more saline waters. Irrigating with a very low leach- ing fraction can cause salts to build up in the soil to toxic levels. Potential mitigative measures for each of the aforementioned impacts of saline water irrigation are discussed in the following sections. 5.3.5.1 Mitigative Practices for Salinity Control in Soils There are three methods by which salinity in soils can be con- trolled. These are leaching with irrigation water, conversion of alkali carbonates into sulfates and control of evapotranspiration (Brady, 1974). 143 ------- Leaching of salts from the soil profile should be done with irri- gation waters having small amounts of exchangeable sodium. This works well on pervious soils whose salts tend to be neutral and high in cal- cium and magnesium. Removal of neutral salts may increase alkalinity because of increased sodium saturation and consequent increases in hydroxyl ion concentrations. This can be avoided by treating with gyp- sum or sulfur which will convert sodium carbonates or bicarbonates to sodium sulfate. Conversion of alkali carbonates to sodium sulfate takes place according to the reaction Na 2 CO 3 + CaSO 4 CaCO 3 + £4a 2 SO 4 where sodium sulfate is a leachable salt. This method leaves the cal- cium carbonate in the soil. Several tons of gypsum per acre may be required and the soil should be kept moist to hasten the reaction. Application of sulfur to soils in the presence of water creates sulfuric acid which not only converts the carbonates but reduces alkalinity as well. The reaction is NaCO +HSO ‘CO +HO+NaSO 2 3 2 4 2 2 2 4 Using this method the sodium sulfate can be leached and the carbonate radical is eliminated. Control of evapotranspiration to control salts is still untenable for large acreages at this time. However, this method can be utilized in gardens by covering areas between rows with dark polyethylene films. This not only prevents evapotranspiration from these areas, which causes salts in solution to migrate upward in the soil profile, but it prevents losses due to weed growth and consumption. Although steps are taken to reduce salinity in soils, the fact re- mains that some crops simply are more tolerant to elevated levels of salinity than others. Therefore, good management of saline soils re- quires selection of the proper crop. Table 5.3-5 shows crops that could conceivably be grown in the Poplar basin and their relative tol- erance to salinity. Tolerance to salinity is governed by many factors and is generally difficult to predict. Stage of growth and rooting habits are among these factors. Seedlings are in general more susceptible than estab- lished plants. Deep-rooted crops are more tolerant than shallow-rooted species. Plants ajso respond differently to similar concentrations of different salts. Selection of plant species must be done primarily based on experience but with proper salinity management a wider variety can be grown with satisfactory yields. 144 ------- Table 5.3-5 RELATIVE TOLERANCES OF VARIOUS CROPS AND FORAGE SPECIES TO SALINITY ARRANGED ACCORDING TO DECREASING TOLERANCES WITHIN GROUPS; MODIFIED FROM ALLISON (1964) AND FROM HEM (l97O).* Tolerant to —Semi-Tolerant and Moderately Tolerant— to _S nsitiv Field, Truck, and Fruit Croj s Barley Sugar Beets Garden Beets Ka 1 e Aspa ragus Spinach Rye Wheat Oats Corn Flax Sunfl ower Tomato Broccol i Cabbage Cauliflower Lettuce Sweet Corn Potato Bell Pepper Carrot Onion Peas Squash Cucumber Field Beans Radish Green Beans Apple Boysenberries Blackberries Raspberries Strawberries Forage Species Sal tyrass Bermudagra ss Tall wheatgrass Rhodesgrass Canada wildrye Western wheatgrass Tall fescue Barley (hay) Birdsfoot trefoil Sweetcl over Perennial ryegrass Mountain brome Harding grass Beardless wildrye Strawberry clover Dall isgrass Sudangrass Hubam clover Alfalfa Rye (hay) Wheat (hay) Oats (hay) Orchardgrass Blue grama Meadow fescue Reed canary Big trefoil Smooth brome Tall meadow oatgrass Mu kvetch Sourcl over White dutch clover Meadow foxtail Alsike clover Red clover Ladino clover Burnet */\fter Kiarich, 1978 ------- 5.3.5.2 Mitigative Irrigation Practices for Salinity Control in Return Flows Surface return flows or tail waters are very rarely treated and sub-surface return flows are virtually impossible to treat. It is therefore imperative that practices be adopted to mitigate the water impacts of increased irrigation water utilization in the field. These measures can be broken down into two basic groups, either improved water conveyence or improved on-farm management. Improving conveyance Seepage out of irrigation diversion ditches is a major source of salinity resulting from irrigation. The hydraulic head causes leaching of mineral salts out of soils directly beneath the ditches and can move salts to shallow ground water aquifers, from which they may enter the river. Additionally, for irrigation water already carrying salts, evaporation from these shallow conveyences may result in an increase in concentration of salts which may be harmful to plants. Both of these conveyence losses decrease the efficiency of the irrigation system and cause the gross diversion requirements to increase. Conveyence effi- ciency can be increased by lining channels with a concrete slip or a plastic membrane. This prevents losses to ground water and also leach- ing beneath ditches. The next level practice would be conduits of buried PVC pipe which would preclude both seepage and evaporative losses. Friction in pipe runs may require that pumps be installed to provide the necessary flows. Naturally, these practices can be adopted for both irrigation canals and for laterals. Proper management of turn-out volumes by metering can also reduce over-irrigating and subsequent impairment of return flow quality. On-Farm Management Practices On-farm management practices for reducing salinity in return waters can be broken down into three categories: o Lining of on-farm conveyences • Altering irrigation practices or switching to a more effective system • Education of operators the first of which has been discussed in the previous section. Salinity pickup by irrigation waters cannot be wholly eliminated because of the need to provide a flow of water through the root zone which ameliorates the concentrating effects due to evapotranspiration. This quantity of water over and above the crop needs required to leach 146 ------- salts away from plant roots is known as the leaching fraction. Due to non-homogeneity of the soils water is normally applied such that the species with the highest water holding capacity will receive the re- quired leaching fraction resulting in over-irrigation on the remainder of the field. Obviously, one method of reducing salt pickup is to in- crease the efficiency of water applications. The various methods will be briefly discussed in increasing order of efficiency, with suggestions for efficiency improvement within each discussion. Spreader Dike or Level Border Irrigation Border irrigation is so named because water is spread over the field by a system of earth dikes or borders which keep the water within specified bounds. Border systems are well suited for alfalfa and small grains and consequently have been popular in the Poplar River Basin. With level border irrigation water is turned onto level plots to form basins from which infiltration takes place. There is no surface return flow from these systems. The average U.S. efficiency for level border irrigation is about 59 percent (Evans, etal., 1978). Efficiences of 80 to 90 percent can be realized with proper management. Good management requires level fields so that water will not collect disproportionately in certain areas, insuring uniform infiltration. The amount of water turned into the system should be precisely regulated so that over-topping of dikes and excessive deep seepage does not occur. Flood or Furrow Irrigation Flood irrigation involves the application of water into small fur- rows which traverse the field slope. To apply water efficiently, the inlet discharge and duration of flow must be a function of soil proper- ties such as water-holding capacity and infiltration rates, field slope and furrow geometry. As water is inlet to the furrow it advances down slope but initial resistance to wetting by the dry soil causes water not to infiltrate i iimediate1y. Behind the flood “wave” a wetting front advances down the furrow. Ideally, the flow rate and duration can be adjusted so that the quantity of water that infiltrates all along the furrow is uniform. Differences in soil characteristics will cause over- irrigation in instances where the soil with the least water holdina capa- bility is properly irrigated. In these systems tail-water or surface return flow is the result of over-irrigation in addition to augmented seepage losses. According to the soil type, salt pickup from excessive infiltration or sediment erosion from surface return can be the major consideration. There are several ways by which flood irrigation can be made more efficient. The first involves irrigation scheduling. Normally, irri- gation is used when the soil water content drops to 50 percent. The 147 ------- determination of moisture content should always be made at the lower end of the field such that the minimum intake opportunity time can be determined. Flow in the furrow should be adjusted so that the time required for the flow to advance to the end of the field is about 25 percent of the minimal intake opportunity time (Walker, 1978). A second method is called cut-back furrow or flood irrigation. The inlet must be automated such that a large “wetting” flow is admit- ted at the head of the furrow and then the flow is decreased or cut back to a smaller flow to finish the irrigation. By using this method tailwater flows are reduced substantially. Both efficiency and exces- sive percolation losses leading to salt build-up of return flows are decreased. Finally, an alternative whereby tailwater flows could be elimina- ted completely is through collecting and repumping of surface runoff waters. This represents an increase in cost over the cut—back alterna- tive. For flood, as with spreader-like irrigation, land grading will aid the application uniformity and therefore increase water use efficiency and salinity control capability. According to Evans (1978) application efficiencies in Colorado for this type of irrigation is about 64 percent with the possibility of 85 to 90 percent efficiencies under well managed systems. Sprinkler Irrigation Irrigation by sprinklers is desirable because of the high unifor- mity of application and excessive losses due to percolation and surface runoff can be effectively minimized. Application efficiencies are normally in the 80 to 90 percent range. This method has the additional advantage that the leaching fraction may be reduced without serious crop effects. Evans, etal., (1978) reported that studies at the U.S. Salinity Laboratory have shown that the leaching fraction can be reduced by one-fourth of present values without a reduction in alfalfa yields. Because percolation losses are minimized, nutrient losses are reduced also. In fact, some water soluble fertilizers can be applied directly through the sprinkler system. As a rule of thumb, with systems yielding increasing application efficiency the water quality of the water used for irrigating should be better. Particulates in water flowing through sprinkler systems can cause corrosion and wear on piping and valves, and can clog sprinkler nozzles, whereas this causes no problems in surface systems. Water of poor quality can leave deposits on plants and cause burning which may lower the aesthetic quality of the fruit or cause physiological effects. Deposition of fine particles on the soil surface can also cause crust- ing which may reduce infiltration rates and promote runoff from both natural rainfall and sprinkler applications. 148 ------- In addition to better water quality requirements, sprinkler systems involve a higher capital outlay and higher operating costs, if pumping is required. Labor costs usually are substantially less and can be made even more so because of the compatibility of sprinkler irrigation and automation. Soil moisture sensors (tensiometers) have been used with microprocessor systems to integrate soil moisture readings from all over the field and automatically trigger an irrigation when soil water tension falls below a specified level. This type of irrigation naturally requires advanced scheduling techniques and technically qual- ified operators. Trickle Irrigation Because of the types of crops grown in the area, trickle irrigation does not seem to be a viable alternative for improving irrigation effi- ciency and reducing salinity. It is normally used on widely spaced crops (orchards, for example) and it is more cost effective for those types of crops. At this time, perforated tapes are available such that trickle systems have begun to be used for row crops. These are generally high value crops such as tomatoes or other similar produce. The high salt content of the Poplar River would make trickle irrigation difficult. Operator Education The best irrigation system or management practices for a given sys- tem are only as good as the expertise of the operator allows. Normally, systems which are capable of increased efficiences and therefore better salinity control require increased levels of operator technical capa- bility. Experience has shown that most operators know when to apply water but not how much water to apply and many operators tend to over- irrigate. Many states have county programs which educate operators in scientific irrigation scheduling and water application. Such a program, if it does not exist, is recommended if projected levels of irrigation in the Poplar River Basin are realized. 5.3.5.3 Source Control of Salinity Increased TDS concentrations can also be potentially controlled at the source. There are two main alternatives: • Control of Fife Lake overflows. The relatively high salinity of Fife Lake overflows may exert considerable influence on reservoir TDS concentrations. A poten- tial control measure would involve diking to control releases at Fife Lake during periods of maxirnun poten- tial for downstream impact. 149 ------- • Prevention of discharge or treatment of ash lagoon decant, ash lagoon seepage and mine dewatering effi uent. As discussed in Section 5.3.1 the routing of the ash decant to the Cookson Reservoir increases the TDS and boron concentrations in the upper East Fork significantly. Saskatchewan Power Corporation has pro- posed to recycle the ash decant to the plant and minimize seepage from the ash lagoons (IJC Hearings, 1979). The proposed plan would be to compact 300 mm of glacial till to limit the seepage to less than 2 2./sec of which an estimated 0.2 2,/sec would enter the reservoir. The remainder (approximately 1.4 2./sec) enters the Empress Gravel aquifer and flows toward the East Fork. Dilution of approximately 10:1 would occur from underfiow from Cookson Reservoir and recharge from the glacial till based on ground water modeling by SPC. The estimated boron concentrations with two power plants in the upper East Fork would be 2.3 to 3.3 mg/ 2 . if no ground water mounding occurred and 2.6 to 5 mg/2. if mounding occurred (IJC Hearings, 1979). The latter concentrations are about 50 percent of the values for scenario 8A. Thus, the impacts on crops of scenarios 4A and 8A represent a “worst case”. With effective control of the ash lagoon seepage the concentrations could be reduced nearly to the values for scenarios 28 and 29. 150 ------- 5.4 SOCIOECONOMIC IMPACTS OF POWER PLANT CONSTRUCTION 5.4.1 Introduction This section describes the socioeconomic impacts that may occur in the Poplar River Basin as a result of the construction of a series of coal-fired plants by Saskatchewan Power north of the U.S. —Canadian border. As in previous sections, the impact area for this portion of the study will be in Daniels and Roosevelt counties. The potential economic impacts that can occur during the construction phase are ex- penditures on materials for the plant itself, and expenditures made by the construction workers in the local area for goods and services during their stay. Both of these sources of impacts are examined, and an estimate is made of the amount of money spent annually in Daniels and Roosevelt counties due to the construction project. Construction of the first of Saskatchewan Power’s coal-fired plants near Coronach, Canada began in August, 1975 and is expected to be completed in the spring of 1980 (Mathew, 1979). The site is roughly five miles southeast of the small town of Coronach, which is about seven miles north of the U.S. -Canadian border. A second unit is ex- pected to be constructed between the fall of 1979 and the winter of 1982. 5.4.2 Description of the Construction Work Force The work force at the Poplar River Plant consists of workers from various union contractors. The size of the construction crew has ranged from about 50 at the beginning of the project to a peak of ap- proximately 600 workers in October, 1978. Figure 5.4—1 shows the fluctuation in the work force over the course of the project. In gen- eral , the crew averaged about 450 to 500 workers during the major portion of the construction, decreasing in the winter months when no outside work could be done, and gaining strength during the rest of the year. Between May and August, 1978, however, a strike at the plant reduced the work force to almost zero (Cairnes, personal communication). Most of the construction force lives in the construction camp built on the site of the first unit. The camp consists of housing, a dining hall, and a recreational center providing workers with a gym, movies, television, pooi table, and other types of entertainment. Workers who brought their families to the area cannot live in the camp and live instead in Coronach and other small Canadian towns in the plant’s vicinity (Mathew, personal communication). No workers live across the border in the U.S. because of the re- strictions on the hours that the border is open. Traffic can only move across the border on Highway 13 between 9 A.M. and 6 P.M. Therefore, there have been no direct impacts of plant construction on U.S. employ- ment rates. 151 ------- 650 600 , 550 500 450 o 400 I- 0 350 c c I- 300 0 o 250 LI 0 200 150 100 50 0 SPRING SPRING 1975 1976 1977 1978 1979 1980 1980 YEAR BY QUARTERS ESTIMATED HISTORICAL CONSTRUCTION WORK FORCE PREDICTED FUTURE CONSTRUCTION WORK FORC Source SRI International estimate using data from Ken Cairnes, telephone conversat ion, May 1979 Figure 5.4-1 ESTIMATED CONSTRUCTION WORK FORCE PROFILE, SASKATCHEWAN POWER PLANT UNIT 1, 1975 THROUGH 1980 ‘ I I I ------- 5.4.3 Economic Impacts from the Plant No spending on plant materials and equipment has taken place in Daniels or Roosevelt counties. Saskatchewan Power representative, Wayne Nordquiest, estimated that approximately $50 million of the $190 million total construction costs of Unit 1 were spent on parts and machinery in the U.S.; however, none of this money went to companies in Daniels and Roosevelt counties. Instead, the $50 million was spent on specialized pieces of equipment that were purchased outside these counties. 5.4.4 Economic Impacts from the Construction Workers Interviews with plant representatives and others indicate that the construction workers have been purchasing many goods and services in the U.S. (Bowler, Kenny, and Cairnes, personal coniliunications). In spite of custom charges, many goods are less expensive in Scobey and Plentywood. In addition, Coronach is a small town (population of 379 in 1971), so the workers find a greater selection of goods and less wait for services in the larger nearby towns of Scobey and Plentywood (populations of 2,041 and 3,126, respectively, in 1970). No precise estimate of the amount of money spent by construction workers in Daniels and Roosevelt counties is available. A rough esti- mate, however, can be made, and the impact that these expenditures are having on the counties can be estimated by examining county personal income and retail sales data. The supervisor of one construction crew estimated that his workers spend approximately $100 per week when they spend the weekend in a nearby U.S. town. Of this, about $70 is spent on a hotel room and entertainment, and the remaining $30 is spent on food, clothing, and miscellaneous goods and services (Sooley, personal communication). Sooley further estimated that approximately 15 percent of the construction crews went to the U.S. on any given weekend. As a basis of estimating impact, it is assumed that a maximum of 10 percent of the workers go to Scobey, and the remaining 5 percent go to towns such as Plentywood and Glasgow in nearby counties. Using these assumptions and estimates, it can be calculated that the range of expenditures the construction workers would make in one year in Daniels County would be between $200,000 and $300,000. This figure assumes a construction work force of 450 to 500. It is estimated that Roosevelt County receives no expenditures from the construction workers because the largest town in the county, Wolf Point, is about 75 miles from the construction camp. As indicated in Table 5.4-1, personal income fluctuates sharply from year to year in both counties, because of large yearly variations in agricultural harvests and crop prices. The percentage change in nonfarm income also fluctuates greatly, though not as much as farm income. 153 ------- Table 5.4-1 TOTAL PERSONAL FARM AND NONFARM INCOME DANIELS AND ROOSEVELT COUNTIES 1972-1977 Source: Montana Department of Community Affairs, Division of Research and Information Systems, “County Profiles,” unpublished. Adjusted to constant dollars. Total Labor and Proprietors’ Income (thousands of 1975 dollars) Year Total ______— Roosevelt Nonfarm Total Farm Percentage Annual Change in Nonfarm Income Daniels Roosevelt 1972 1973 1974 1975 1976 1977 Daniels Farm $12,740 21 ,8O2 11,658 12,671 10,051 6,209 $18,737 28,407 18,360 19,836 17,446 13,591 $5,997 6,605 6,702 7,165 7,395 7,382 $41,138 59,559 38,122 42,940 38,707 31 ,248 Non farm $25,846 27,233 26,359 27,774 28,146 30,237 $15,292 32,326 11,763 15,166 10,561 1,011 10.1% 1.5 6.9 3.2 -0.2 5.4% -3.2 5.4 1.3 7.4 ------- Table 5.4-2 shows a similar picture for retail sales. Sales vary considerably from one year to the next. The large decline in sales between 1973 and 1974 in Daniels County is probably related to the large decline in income. Farm income decreased dramatically in Roosevelt County between 1976 and 1977 due to a substantial decline in prices received by farmers for spring wheat. Neither table shows a clear increase in income or sales that might be attributable to con- struction worker expenditures. 5.4.5 Secondary Impacts Construction workers spend a portion of their wages for goods and services in Daniels County. The recipients of those payments treat them as additional income and likewise spend some. Therefore, the initial expenditure is actually respent a number of times throughout the economy, generating secondary income, which is a multiple of the initial injection. Multipliers are calculated by the Bureau of Economic Analysis (BEA) for 53 industrial sectors in each of the 173 BEA economic areas of the U.S. Daniels and Roosevelt counties are in BEA area number 93. Industrial sector number 54 (Trade) was chosen for these counties, which has a multiplier of 1.85 for Daniels and Roosevelt counties, according to the U.S. Bureau of the Census (January, 1977). Simply applying the multiplier to the change in expenditures would not accurately represent the impact, however, because of the inter- dependence between the nearby counties. Spillover effects between Daniels County, the area of direct impact, and other counties occur, which can be calculated using a procedure developed by J.A. Chalmers, et al., (1977). In this study, they noted a hierarchical relationship between different kinds of counties. For example, certain counties, designated level-3 counties, appear to serve as central market areas for groups of other counties (level-2). Level-2 counties, in turn, support groups of still lower-level counties and receive spillover effects from them. Following Chalmers’ ranking scheme, we assigned each county in the BEA area a rank of 1, 2, or 3. As in Chalmers, all level-i counties in BEA area 93 are allocated 12 percent of the indirect impacts resulting from the direct expendi- ture of $200,000 to $300,000. The 12 percent is then distributed to individual level 1 counties within the BEA region by the ratio of the population of the level—i county to the total population of all level-i counties in the BEA region. Using this methodology, secondary impacts can be calculated. Daniels County receives approximately Sl6,000 to S24,000 annually in secondary impacts. Roosevelt County, although it receives no direct 155 ------- Table 5.4-2 TOTAL RETAIL SALES DANIELS AND ROOSEVELT COUNTIES 1973- 1977 Total Retail Sales (thousands of 1975 dollars) Percentage Annual Change Year Daniels Roosevelt Daniels Roosevelt 1973 $7,379 $23,864 1974 3,748 23,852 -49.2% -0.1% 1975 3,407 21,681 - 9.1 -9.1 1976 3,425 20,853 0.5 —3.8 1977 3,552 20,291 3.7 -2.7 Source: Sales and Marketing Management Magazine, Survey of Buying Power (1974-1978) and adjusted to constant dollars. 156 ------- impacts, receives secondary impacts of about $53,000 to $79,000 annual- ly--a larger share than Daniels County because of wholesale and retail purchases generated by activity in Daniels County. This procedure may tend to overestimate the secondary impacts in Roosevelt County since Wolf Point is so far from Scobey. In summary, direct and secondary impacts combined total about $216,000 to S324,000, or 6.3 percent to 9.5 percent of retail sales in Daniels County in 1975. The total impact of $53,000 to $79,000 repre- sents 0.2 percent to 0.4 percent of retail sales in Roosevelt County represents a noticeable addition to sales, and may be preventing the county from experiencing the decline in retail sales that occurred in Roosevelt County. Both counties had declines in sales of about 9 per- cent between 1974 and 1975. Daniels County however, recovered in the following two years, whereas Roosevelt County continued to decline by about 3 percent to 4 percent annually. Expenditure changes can also be related to personal income. Using the fact that income is roughly 0.3 percent of gross output, or sales, it can be calculated that the total increase in sales resulting from the construction workers amounts to about 0.3 percent to 0.5 percent of personal income in Daniels County in 1975, and 0.9 percent to 1.4 percent of nonfarm personal income for the same period. In Roosevelt County, the increase in sales represents an increase of less than 0.1 percent for both total and nonfarm personal income in 1975. Although the revenue from the construction workers represents a benefit that local communities such as Scobey will miss when the con- struction is ended, this impact is far less significant to Daniels County than the impact of changes in prices received by farmers. The effect of wheat prices greatly overshadows any possible impact that construction workers could have in this area. 157 ------- 5.5 SOCIOECONOMIC IMPACTS OF APPORTIONMENT 5.5.1 Introduction The apportionment of water from the Poplar River will affect the amount of land irrigated in Daniels and Roosevelt counties and the qual- ity of the irrigation water. This section estimates economic conditions, from 1975 to 2000, and the impacts of Apportionment VI on farm income and total income in Daniels and Roosevelt counties. 5.5.2 Future Conditions The Poplar River Basin is a sparsely populated, rural area that is unlikely to change significantly before 2000*. The only significant development expected to take place over the next 25 years is the con- struction of a potash plant, and the likely population influx associated with the plant is included in the projections. Significant deposits of lignite occur in the region of the Fort Peck Indian Reservation. Unpub- lished data indicate that, under reasonable projections of future coal demand, it is unlikely that these deposits would be developed and mined before 2025. Compared with other coal resources, the lirinite is econom- ically and cieoloqically unattractive (Yabroff and Dickson, 1979). However, federal policies promoting coal development to reduce dependence on imported petroleum could overcome the market constraints. It is possible that some development could occur in the vicinity of McCone County by 1990 although there is substantial local resistance to large energy developments in McCone County (Parfit, 1980). Two coal-related projects investioatinq sites near Circle, Montana are the Basin Electric Power Cooperative and the Circle West Project. The planned development by Basin Electric would be two 500 MWe coal-fired power plants with the first unit to begin operation in 1988. Basin expects to select a site in early 1980 (personal communication - EPA, 1980). Sites being consid- ered for the Circle West Project are in McCone County. Table 5.5-1 shows population and employment projections for 1980, 1985, and 2000. The ratio of employment to population for the period 1971 to 1977 was used in estimating future employment, based on the pop- ulation projections. Because no discernible trend was identified, future employment was estimated as the average of the employment-to-population ratio for 1971 to 1977. The average ratios for Daniels and Roosevelt counties, respectively, were 0.47 and 0.42. *The projections presented here are based on population projections made by the Montana Department of Community Affairs. 158 ------- Table 5.5-1 PROJECTED POPULATION AND EMPLOYMENT DANIELS AND ROOSEVELT COUNTIES -- 1980, 1985 and 2000 Population’ Employment 2 Year Daniels Roosevelt Daniels Roosevelt 1975 3,100 10,300 1,480 4,430 1980 3,100 10,700 1,500 4,500 1985 2,900 10,900 1,400 4,600 2000 3,400 11,500 1,600 4,800 Sources: 1. Montana Department of Community Affairs, Research and Information Systems Division, “Montana Population Projections, 1980-2000) (July, 1978) 2. SRI estimate Future income levels in Daniels and Roosevelt counties were esti- mated as the sum of wage and salary income, proprietors’ income, property income, and net transfer payments. Wage and salary income was projected using projections of future wage and salary employment and 1975 wage levels. Income of nonfarm proprietors was based on the number of proprietors times the average proprietors’ income for 1975. Projecting the income of farm proprietors was complicated by having to account for additional income because of the increases in irrigated lands. Based on data of the USDA Cooperative Extension Service, conversion of existing dryland acreage to irrigated acreage was estimated to increase net incomes by $40 to $50/acre (Luft, 1979; Luft and Griffith, 1978). To be conservative and to account for pos- sible yield and technological changes over the next 20 years, $50! irrigated acre was used to project the additional agricultural income expected in the two counties. The change in irrigated acreage for 1985 and 2000 is taken as the difference between irrigated acreage in the Poplar River Basin in 1975 and the desired irrigated acreages for 1985 and 2000. The projections for 1985 and 2000 are based on the completion of two reservoirs on the Poplar within the Fort Peck Indian Reservation. The combined storage capacity of the reservoirs is app’oxiniately 152,400 ac-ft. It was assumed that irrigated land would be converted from existing unirrigated cropland. Because most cropland in Daniels County is within the Poplar River Basin, no other factors are likely to affect agricultural income. In Roosevelt County it was assumed that conditions outside the Poplar River Basin would remain constant. This assumption will tend to over- estimate impacts because the projected conditions in Roosevelt County do not allow for additional irrigation or conversion of pasture and range to cropland. 159 ------- Other sources of income, rent, interest, and net transfer payments were estimated from their historical relationship to the total of wage, salary, and proprietors’ income. The results are summarized below in millions of 1975 dollars. Farm Proprietors’ Total Personal Income Income Daniels County: 1975 $11.9 $25.5 1985 12.0 24.7 2000 12.1 26.8 Roosevelt County: 1975 13.6 55.6 1985 14.1 56.2 2000 14.6 59.2 In constant dollars, the projected gains are quite modest in Daniels County. Income of farm proprietors is projected to increase by only 1.7 percent between 1975 and 2000 and total personal income by 5.1 percent. In Roosevelt County, the gains are somewhat larger, but hardly robust: 7.4 percent for income of farm proprietors and 6.5 per- cent for total personal income. These projections reflect the historical experience of agricultural income in the region. The changes in income result from changing com- modity prices--especially wheat. Real growth over the long term has been slight. The outlook for the future is for continued fluctuations but for no dramatic increases. 5.5.3 Impacts on Income The impacts of the apportionment scheme on Montana agriculture in larue part depend on the amount of land that is developed for irrigation. Projections of irrigated acreage that are desired by Montana interests are oresented above, and will be used as the basis for estimating im- paces. The amount of irrigated land that is likely under the apportion- ment will depend on the farmers’ perceptions of the risks and returns invol ved. Installation of a sprinkler irrigation system requires an invest- ment of between $160/acre for a hand-move system and $340/acre for a circular self-propelled system (Luft, 1979). Side-roll wheel-move sys- tems can be installed for $250 to $270/acre (Luft, 1979). Analysis of the side-roll wheel-move systems indicates that additional income of $46! acre is possible with irrigated alfalfa. Conversion of dryland wheat to irrigated wheat would result in additional income of $42.60/acre (Luft, No Date Given). 160 ------- Side-roll irrigation systems are used as the basis for calculating impacts because they provide a convenient middle ground between the ex- tremes of hand-move and center-pivot systems. Buying an irrigation system requires that the farm operator assume the risk of no return on his investment in a dry year. He must therefore be convinced that over the long run his investment will be profitable. That is, his returns in years with sufficient water must exceed carrying costs in dry years. The additional fixed costs of a side-roll irrigation system are approx- imately $35/acre. If, as discussed above, the additional income from irrigated wheat is $42/acre, a farmer could invest in an irrigation system based on the mean flows from the Poplar River. In years when flows are less than the mean, fixed costs could be covered as long as yields do not drop more than 16 percent. However, a definite risk of bankruptcy is encountered if several dry years occur consecutively. The risks with irrigated alfalfa are slightly less, allowing on the average a margin of Sli/acre over fixed costs which is equivalent to 24 percent of average yields. Based on the foregoing, it is assumed that farmers in the Poplar River Basin will install irrigation systems on acreage irrigable with the mean flows expected under the apportionment. This implies making use of the acreage irrigable with the mean flows for June in 1985--13,573 acres. Moreover, it assumes that farmers can recover their investment before the fourth power plant is completed, causing mean flows for June to drop so that only 10,936 acres can be irrigated in 2000. The preceding line of reasoning presents a plausible scenario for estimating impacts. An investment of approximately $3.0 million in irri- gation systems would be required for the more than 10,000 acres in the Poplar River Basin. Given the region’s long history of dryland farming, this constitutes a large, risky investment. The cautious farmer will wait to ascertain how the apportionment affects flows before he decides to make such an investment. However, in estimating impacts, the assump- tions above provide a conservative approach. The apportionment will cause a change in the irrigable acreage in Daniels and Roosevelt counties (Table F-i) and a change in yields on irrigated lands because of lowered water quality. The income loss caused by the change in acreage is estimated as the difference between net in- come for irrigated crops and net income for dryland farming of the same crop. For the impact calculations this difference is assumed to be $50! acre. This is higher than the increases in net income estimated by Luft for alfalfa and wheat; however, it does allow for the possibility of higher wheat and alfalfa prices in the future. The increase in net income for irrigated crops is assumed to be earned only when irrigation is possible throughout the growing season. Therefore, the change in irrigable acreage is calculated using irrigable acres for mean flows in August. The irrigable acres shown in Table F-i 161 ------- are based on water requirements and losses. In practice, additional water may be applied to leach salts from the soils. It is assumed that 20 percent more water than is needed for plant growth will be used for leaching. Table 5.5—2 shows the changes in irrigable acres and income due to apportionment. Income changes due to water quality are shown in Table 5.5-3 under median water quality and rainfall conditions. Yield decreases up to 6 percent would be predicted if the leaching fraction decreased to 0.1 in Roosevelt resulting in an estimated decrease in income of $6,798 for 1975 and -$116,794 for 1985. Table 5.5-3 CHAr GE IN YIELD AND PER-ACRE REVENUES FOR WHEAT Irrigated Total Yield Per-Acre Acres Income Location Scenario* Change Change Affected Change Daniels 1975 (1 plant) -11% —$24 1,391 -33,400 County 1985 (2 plants) -20 — 44 1,520 -66,900 Roosevelt 1975 (1 plant) +8% +$17 515 +20,600 County 1985 (2 plants) +8 + 17 8,848 +150,400 *1975 is model scenario 4A. 1985 is model scenario 8A. The change in income resulting from water quality changes depends upon the sensitivity of a crop to boron and other salts and the mix of crops planted. Of the four major crops in the area, alfalfa is the most tolerant and oats the least tolerant. Wheat and barley are intermediate in tolerance. The yield losses expected for wheat are less than those for barley under similar conditions; however, because wheat has a higher price, the income losses would be greater (on a per-acre basis) for wheat. Water quality-caused reductions in yield are worst on the East Fork. In Roosevelt County the water quality changes are underestimated by the model so the yield could be less than predicted. The change in farm income will result in secondary income changes in other sectors of Daniels and Roosevelt counties, and in nearby trading centers that serve residents and businesses in the two counties. BEA Area 93 has a multiplier of 1.629 for the field crop sector in which wheat and alfalfa fall. This is used to estimate the total changes in personal income. Then, taking into account the hierarchical relationship among counties in the BEA area, the total impacts are apportioned among counties. (See the explanation in section on construction period impacts and Chalmers, etal., 1977.) Table 5.5-4 summarizes the impacts on total personal income. 162 ------- Table 5.5—2 CHANGE IN FARN INCOME RESULTING FROM APPORTIONMENT ONLY Estimated and Projected Irrigated Mean Acreage Difference Change as % of Acres Affected by Irrigable in Irrigated Income Farm Proprietor’s Project in August Acres Change Income Daniels County 1975 2,826 1,390 —1,436 —$71,800 —0.6% 1985 3,575 1,519 —2,056 —102,800 —0.9 2000 5,342 1,521 —3,821 —191,050 —1.6 Roosevelt County 1975 515 515 0 0 0 1985 8,848 8,848 0 0 0 2000 17,182 3,488 —13,694 —684,700 —4.8 ------- Table 5.5-4 IMPACTS OF APPORTIONMENT AND WATER QUALITY ON PERSONAL INCOME IN DANIELS AND ROOSEVELT COUNTIES (Dollar Figures are in Thousands of 1975 Dollars) County Change in Impact as and Change in Induced Income Total Change Percent of Year Farm Income in County in Personal Income Personal Income Daniels 1975 $-105.2 $ -7.9 S-113.1 -0.4% 1985 -169.7 -12.8 -182.5 -0.7 2000 -258.0 -19.5 -277.4 -1.0 Roosevel t 1975 $ 20.6 $ 1.6 $ 22.2 * 1985 150.4 11.4 161.8 0.3% 2000 59.3 4.5 63.8 0.1 *Less than 0.05 percent. In both Daniels and Roosevelt counties the secondary income changes plus the change in farm income amount to 1 percent or less of personal income in 2000. The losses in Daniels County are partially offset by gains in Roosevelt County but the net impact is negative. The changes estimated are far less than historical variations in personal income that arise from weather variations. Approximately 50 percent of the secondary impacts may flow to Minot, North Dakota (Ward County), which is the major trading center for BEA Area 93. This would have a minimal impact amounting to less than 0.1 per- cent of personal income in Ward County in the year 2000. The foregoing has presented an estimate of impacts that might result from apportionment of the water flows in the Poplar River; however the analysis is influenced by many underlying assumptions. Some of the more important figures that have been included are the selling price of wheat and alfalfa, the cost of water to farmers, the value of cropland, the cost of sprinkler systems, and farm operating costs. In fact, the number of possible combinations that could be considered is unwieldy. There- fore, to indicate the upper range of possible impacts, the worst-case approach was used. That is, it was assumed that the number of irrigated acres affected by the apportionment was equal to the total projected irrigated acreage affected by the power plants in the Poplar River Basin. This is equivalent to cutting off all irrigation waters, leaving on’y dryland farming in Daniels and Roosevelt counties--a possibility in ex- tremely dry years or if water quality were reduced to harmful levels. The impacts on farm income resulting from the conversion of all irrigable lands to dry land farming are shown in Table 5.5-5. 164 ------- Table 5.5-5 MAXIMUM POSSIBLE IMPACTS ON FARM INCOME Percent County Change in Change in Farm Change of Farm and Irrigated Lands Proprietors’ Income Proprietors’ Year ( acres) ( thousands of 1975$) Income in Region Daniels 1975 -2,826 $ -140 -1.2% 1985 —3,575 -180 -1.5 2000 —5,342 -270 -2.2 Roosevelt 1975 -515 -26 -0.2 1985 —8,848 -440 -3.1 2000 -17,182 -860 -6.0 Total s 1975 —3,341 —170 -0.7 1985 -12,423 -620 -2.4 2000 -22,524 -1,130 -4.3 The largest absolute and percentage impacts would occur in Roosevelt County where farm income could be reduced by 6 percent in 2000. Within boundaries of the Fort Peck Indian Reservation, the impacts would be much higher on a percentage basis. However, all the Indians do not own and operate farmland there. Gross value of products (crops and livestock) cirown on Indian lands by Indian operators is estimated to be less than $10 million. In the case of no irrigated lands, impacts on total personal income would be less than 2 percent of personal income in 2000. Spill- over of secondary impacts into other regions would be negligible on a percentage basis. The preceding discussion of impacts has presented the worst case situation. The actual changes in income after the apportionment may be less than indicated above under the mean flow conditions. After con- struction of the reservoirs more land can be irrigated in 1985 and 2000 than in 1975. The average number of irrigation applications per year has been 2.4 so that even under present flow conditions water in August is not adequate to irrigate the full number of acres. Thus, assuming the loss of the full premium is very conservative. 5.5.4 Other Impacts The apportionment could affect the values of irrigated land if water is no longer available. Conceivably, between 1935 and 2000 land values 165 ------- could drop as the amount of irrigable land declines. Based on current crop budgets for the region, the premium for irrigated land is between $50 and $100/acre (Griffith, et al., 1978; Shaefer, et al., 1978A and 1978B). A related impact is the loss of the undepreciated portion of any investment in irrigation equipment. For new systems, the loss could be more than S200/acre. The impacts of the apportionment on farm income and total personal income are unlikely to result in noticeable changes in population. If irrigation water is unavailable, farmers will resort to what they know best--dryland farming. The trend to fewer and larger farms would not be affected by the changes estimated here. An increase in demand for seasonal farm workers is likely to occur if all the growth in irrigated lands takes place as projected. The converse would occur if the amount of irrigated land, and, therefore, crop yields are diminished. It is difficult to estimate the number of seasonal employees affected because no data exist regarding the current seasonal farm employment available. However, in Daniels and Roosevelt counties together fewer than 300 full and part-time workers were employed in agriculture in 1977. The down- ward trend in agricultural employment is expected to continue; therefore, in 2000, less than 5 percent of total county employment will be in agri- culture. As a result, the likelihood of significant impacts on employment is small. 166 ------- 5.6 BIOLOGICAL IMPACTS 5.6.1 Impacts of Atmospheric Emissions on Terrestrial Biota 5.6.1.1 Gaseous Emissions The effects of primary gaseous pollutants on terrestrial vegeta- tion and animals can be categorized in terms of exposure duration and dosage. Three broad categories can be distinguished: acute, chronic and long-term. Acute effects are those which result from short-term exposures to relatively high concentrations of pollutants. Observable effects which result from exposures to comparatively low levels of pollutants for periods of months to years are referred to as chronic, while the effects of exposure to pollutants for decades or longer are classified as long—term. Acute effects result from direct injury to the biota and are typ- ified by leaf damage and lesions in an animal’s respiratory tract or other serious debilities. While chronic effects may be expressed similarly to those which have been described as acute, more often they are expressed as subtle changes in the ecosystem. These subtle changes, moreover, may represent a change in the species composition of a well defined natural vegetation assemblage due to the loss of a pollutant sensitive species, or they may represent a decrease in num- bers of wildlife in a particular area due to concomitant habitat dep- redation. Long-term effects on the other hand are the result of secondary or tertiary interactions and are always manifested as subtle changes in the ecosystem or an organism’s susceptibility to respiratory diseases. Sulfur dioxide (SO 2 ) is the most abundant gaseous pollutant pro- duced by coal-fired electrical generating stations, and is therefore of primary concern when considering the impacts on terrestrial eco- systems. Nitrogen oxide emissions (NOx) represent another important pollution source, but because expected concentrations produced in the vicinity of the plant are generally anticipated to remain below acute and chronic injury threshold levels, they are of secondary importance. In addition to considering the impacts associated with the emission of these common pollutants and their singular effects, the additive or possible synergistic effects must also be addressed. Reported threshold limits of selected species to acute and in some cases chronic levels of SO2, NO and combined gaseous emissions are provided in Table 5.6-1; included in this list are important species of grasses, forbs and cultivated crops found in the Poplar River impact area. These empirically determined threshold values rep- resent upper levels of exposure at which no visible injury to the plants was observed. The values presented in Table 5.6-1 are greater than reported acute threshold levels listed for the most sensitive 167 ------- Table 5.6-1 REPORTED THRESHOLD LIMITS OF IMPORTANT NATIVE PLANT AND CULTIVATED SPECIES FOUND IN THE IMPACT AREA TO GASEOUS (SO 2 , NOx AND SO 2 + NOx EMISSION EXPOSURES THRESHOLD LIMITS (uo I JURY OBSERVED) Dose Period of Gaseous Pollutant Exposure conti nuous 502 0.2 ppm - during growing season NO 1.0 ppm — 4 hrs SO 2 + NO, (0.3 ppm + 0.1 ppm) - 4 Arteusia frigida (finged sagewort) 502 NO 502 + NO, 1.0 ppm — 4 hrs 4.0 ppm - 4 hrs (0.6 ppm + 0.1 ppm) - Tingey. ! .t .L.. 1978 Tingey. etal.. 1978 4 hrs Tingey. etal.. 1978 Koeleria cr.xscata (praire june grass) Sc2pa comata (needle and threadgrass) 502 SO 2 NO SO 2 + NO SO 2 SO 2 NO SO 2 + NO 1.0 ppm - 4 hrs 1.2 ppm - 3 hrs (biweekly) 1.0 ppm - 4 hrs (0.3 ppm + 0.1 ppm) - 4 hrs 1.5 ppm — 4 hrs 1.2 ppm - 3 hrs (biweekly) 1.0 ppm - 4 hrS (1.2 ppm + (1.1 ppm) - 4 hrs Tingey. et al. 1978 Wilhour, et at • 1979 Tingey. et al. • 1978 Tingey. !! !L. ’ 1978 Tingey. !!. L-. 1978 Wilhour , !S. J_. 1979 Tingey, !! AL .. 1978 Tingey, et al.. 1978 Medlcac7o sativa (Alfalfa) Stevens and Hazelton, 1976 Stevens and Hazelton, 1976 Stevens and Hazelton. 1976 Wilhour, et aL, 1979 Drei Si nger and McGovern, 1970 Drei singer and McGovern, 1970 Drei singer and McGovern, 1970 Drei singer and McGovern. 1970 Wilhour, et al. • 1979 Tingey, £! i. . 1978 Wilhour, et al. • 1978 Tingey. ! _L . 1978 Tingey. et al. • 1978 Snec i es Reference soutelova oracilis (blue grama) SO 2 so 2 NO 502 + N0 1.2 (0.3 0.5 ppm — 0.5 ppm + ppm — 4 hrs 3 hrs (biweekly) ppm — 4 hrs 0.1 ppm) 4 hrs Tingey, WilPiour, Tingey, Tingey, et al., et al. • et al., etal., 1978 1979 1978 1978 Agropyron (Western smithii wheatgrass) 502 502 1.2 1.5 ppm - ppm - 4 hrs 3 hrs (biweekly) Tingey, Wilhour, et al.. et al. • 1978 1979 Dodd, !! .i. . 1978 Tingey, et al. , 1978 hrs Tingey. !! i•. 1978 502 1.15 ppm — 1 hr 502 0.50 ppm - 3 hrs SO 2 0.25 ppm - 24 hrs or more 502 1.2 ppm - 3 hrs (biweekly) 502 0.70 ppm - 1 hr SO 2 0.46 ppm - 2 hrs SO 2 0.27 ppm - 4 hrs SO 2 0.14 ppm - 8 hrs SO 2 1.2 ppm . 3 hrs (biweekly) Hordoum vuigare (Barley) Tritcum aest.’.,zum (hyslop wneat) SO 2 So 2 Nox SO? + NO 0.6 ppm - 4 hrs 1.2 ppm - 3 hrs (biweekly) 2 0 ppm - 4 hrs (0 6 ppm + 0 1 ppm) - 4 hrs 168 ------- plant species which are presented graphically in Figure 5.6-1. The concentrations and corresponding exposure shown in Figure 5.6-1, how- ever, represent threshold levels for plants growing under the most sensitive conditions and stage of maturity. While such guidelines for chronic exposures are not available, it has been estimated that an ambient S02 concentration of 130 pg/rn 3 (0.05 ppm) on a seasonal or annual average basis represents the threshold level (Mukammal , 1976). Studies were conducted at the Corvallis Environmental Research Laboratory during the spring and summer months of 1977 to investigate the effects of both chronic and multiple S02 exposures on selected small grains, native range grasses and alfalfa growing in the Poplar River Basin (Wilhour, etal., 1979). The results indicated that the yield of duram wheat and barley may be substantially reduced by weekly 72-hr exposures to SO 2 concentrations of approximately 0.15 ppm (400 pg/rn 3 ) and that spring wheat, while more resistant to chronic exposures, may also suffer decreased yield due to SO2 exposures at similar levels. Multiple exposure of these species as well as alfalfa to frequencies varying from once per week to once in five weeks with SO 2 concentrations up to 1.2 ppm (320 pg/rn 3 ) for 3-hr periods, however, had no effect on the yield of the plants. Finally, biweekly exposures for 3-hr at con- centrations up to 1.2 ppm (3200 pg/rn 3 ) had no effect on the growth of either the roots or tops of alfalfa or the following five species of native grasses: crested wheatgrass (Agropyron desertorum) , western wheatgrass (Agropyron smithii) , Russian wild ryegrass (Elymus junceus) blue gramma grass (Bouteloua gracilis) and needle and thread grass (Stipa comata). The combined effects of gaseous emissions, especially the inter- action of SO 2 and NOx, on vegetation are not well understood, and some controversy exists concerning possible synergistic or additive effects. Studies conducted in growth chambers (Bennett, et al. , 1975) indicated that SO 2 and NO applied in combination may enhancithe deleterious effect of these pollutants; relatively high doses of these pollutants, however, were required to cause visible injury. For exam- ple, one hour exposures to a 0.5 ppm S02 + NQx (960 pg/rn 3 NOx and 1301 pg/rn 3 SO 2 ) mixture or to 0.75 ppm (1950 pg/mi) were required to cause visible :Foliar injury in the most sensitive species. Other studies (Tingey, etal., 1978 and Hill, etal., 1974) have been unable to sub- stantiate that mixtures of SO 2 + NO interact to cause greater foliar injury than equal concentrations of single gaseous pollutants. The acute tolerance levels of several plant species found within the im- pact area to mixtures of SO 2 + NO are indicated in Table 5.6-1. Based on the conservative projections provided by the CRSTER air quality model, gaseous emissions resulting from the operation of the proposed generating station will not have a detectable impact on the terrestrial ecosystem. This analysis is based on the specific consid- erations outlined below, but generally is the result of the absence of industrial and urban development within the Poplar Basin and the concomitant excellent baseline air quality conditions. As previously 169 ------- Figure 5.6-1 ‘I a 0 1 Y0R0AMA 0 I 2 3 4 5 6 7 8 - DURATION OF EXPOSUREli, (b) I0 a G I- ) a 7 0 0 4 3 2 (c) 8340 15720 13100 A 0480 a. ‘a a 0 ‘a 1860 5240 2620 0 26200 23580 20960 a 18340 15720 ‘ . 0 13100 ‘ 10480 7860 5240 2620 a DURATION OF EXPOSURE. Ii , (a) INJURY OR DAMAGE POSSIBLE I I I I I I I 0 I 2 3 4 5 6 7 8 DURATION OF EXPOSURE. Dr Source: U.S. EPA, 1973 DOSE-INJURY CURVES FOR (a) S0 2 -SENSITIVE PLANT SPECIES, (b) PLANT SPECIES OF INTERMEDIATE SO2 SENSITIVITY, AND (c) SO 2 -RESISTANT PLANT SPECIES. 170 ------- noted, however, the CRSTER model does not incorporate fumigation events in estimating pollutant concentrations. Estimated maximum ground-level concentrations of gaseous emissions during morning plume fumigation for the worst case atmospheric conditions are of the same magnitude as concentrations associated with acute injury levels for the most sensi- tive plant species. The possible impact of estimated peak concentrations resulting from plume fumigation are discussed in a subsequent section. The area of primary concern for the evaluation of emission impacts is that region within a 50 km (31.1 miles) radius of the plant site. Assuming the operation of four 300 MW units, the yearly maximum 24-hour concentration of SO 2 predicted by the air quality model to occur at a distance of 50 km is 22.8 1g/m 3 or 0.008 ppm; this value is below the minimum detectable limits of baseline measurements in this area. The projected maximum 1-hour SO 2 concentration at this distance at this same electrical generating capacity is 169 119/rn 3 or 0.06 ppm, and this projected concentration is an order of magnitude less than reported concentrations associated with acute injury threshold levels for sen- sitive vegetation. The projected ambient concentrations of NO for this region are similarly below threshold injury levels for sensitive native plants and crops. These projected concentrations for SO 2 and NOx are of particular importance since the air quality model is espe- cially conservative at this distance from the point source. The region described here as the area of primary concern is shown in Figures 5.1-1 through 5.1-4; it lies within Daniels and Valley Counties and represents a total area of approximately 700 km 2 (270 square miles). That portion of the impact area continuously exposed to the high- est concentrations of gaseous emissions and therefore most likely to display the acute and chronic effects of exposure to SO 2 and NOx is within 6-15 km (3.7-9.3 miles) of the stacks. The yearly maximum 1-, 3- and 24-hour ambient SO 2 concentrations projected for any area within this range (for a 1200 MW 2laflt with 0 percent SO 2 control) are 464 ig/m 3 (0.18 ppm), 274 jg/mi (0.10 ppm) and 50 pg/m 3 (0.02 ppm). The projected maximum annual mean SO2 concentration at this distance is 3.064 ig/m 3 (<0.01 ppm). The projected SO 2 concentrations as well as those of NO are considerably less than those associated with acute and chronic threshold injury levels for sensitive vegetation. More- over, the projected levels of these pollutants in combination are be- low reported concentrations associated with combined or synergistic effects. As previously noted, experiments using the most sensitive native grasses found that 4-hour exposures to combined concentrations of 0.3 ppm SO 2 and 0.1 ppm NO 2 were insufficient to induce foliar in- jury (Tingey, etal., 1978). The preceding comoarisons which indicate the absence of injurious levels resulting from the Poplar River plant were all based on the maximum projected emissions at the site, i.e., operation of four 300 MW units with 0 percent SO 2 control. The maximum concentrations occurring near the plant site were also considered. The actual concentrations of gaseous constituents, and the corresponding potential for foliar injury, would be considerably less due to the following factors: 171 ------- 1) Operation of fewer than four units would result in correspondingly lower emission rates. 2) The use of stack emission controls would result in large reductions in ambient SO 2 concentrations. 3) The ambient concentrations of all constituents decrease rapidly with distance from the site. Therefore, most of the Poplar basin would be exposed to maximum projected concentrations greater than two orders of magnitude below the tolerance levels for local agricultural plant species. Areas not subjected to acute or chronic SO 2 exposure can neverthe- less be affected by long-term, low level ambient SO 2 concentrations. The most serious known effect of long-term exposures to elevated sulfur levels is the acidification of soils (Nyborg, 1978). Additionally, recent studies (Rice, et al. , 1979) suggest that a long-term buildup of sulfur in plants could have a detrimental effect on crop yield and quality. However, no studies have been conducted to determine a relationship between excessive sulfur accumulation and plant damage. The acidification of soils is associated with the deposition of H 2 SO 4 in precipitation (acid rain) as well as the formation of H 2 SO 4 in the soil following direct dry deposition of SO 2 . The effects on soils of increased acidity are: an increased solubility of aluminum (Al) and manganese (Mn); deficiency in soil concentrations of calcium (Ca) and magnesium (Mg); and increased hydrogen ion (H+) concentrations. These changes in soil chemistry can adversely affect plant growth and yield. The primary manner in which soil acidity affects plant growth is through aluminum toxicity which begins to occur at a pH around 5.0 - 5.5. Calcium and magnesium deficiencies are primarily a problem associ- ated with forest soils which are naturally acidic. Increased H+_ion concentrations are generally toxic to plant roots only when soils are extremely acidic (pH = 4.0 to 3.0). Nitrogen fixation by symbiotic bacteria associated with alfalfa is inhibited at pH levels less than 6.0. While the accumulation of sulfur can have deleterious effects, sul- fur is also an essential nutrient. The amount of sulfur needed for medium to high crop yields ranges from about 10 to 40 kg/ha yr-i (Noggle and Jones, 1979). At least a portion of a plant’s sulfur requirements can be met by direct uptake of SO 2 from the atmosphere if present at low concentrations (Faller, 1971; Bromfield, 1972; Cowling, et al., 1973; Noggle and Jones, 1979). Beneficial effects r f ambient low level SO 2 concentrations on plant growth when soil concentrations are inade- quate have also been demonstrated (Faller, 1970 and 1971). In addition, sulfur in the form of calcium sulfate (gypsum) is often applied to soils to change part of the caustic alkali carbonates into sulfates. 172 ------- An assessment of the impacts of sulfur deposition on soils must consider not only SO 2 deposition rates but also buffering capacity of the soils and sulfur loss through cropping and leaching. Sulfur emitted to the atmosphere by a power plant can be introduced into the terres- trial ecosystem by wet and dry deposition. There are two methods of estimating the rate deposition of sulfur. The first is based on the assumption that the total amount of sulfur in stack emissions will be equally distributed within a specified area. A second method is based on a calculation of deposition rate as the product of an annual mean SO 2 concentration and an estimated deposition velocity (Fowler, 1973; Garland, 1978). The first method was used by the Montana Department of Health and Environmental Sciences (MDHES) to predict sulfur deposition within the Poplar River Basin (Geihaus and Roach, 1979). The estimate was based on the following assumptions: the operation of a 300 MW plant with zero percent SO 2 control, daily SO 2 emissions of 5.84 . iO kg (6.4 tons), 60 percent deposition of sulfur emissions within a 40 km radius of the source, and equal deposition throu9hout the affected area. The predicted deposition rate was 25.5 kg/ha yr—I of SO 2 or approximately 12.8 kg/ha yr-i of elemental S. An annual deposition rate of 12.8 kg S/ha for the 300 MW plant is equivalent to deposition rates of 25.6 and 51.2 kg S/ha yr-’ for the 600 and 1200 MW plants, respectively. The second method focuses on the contribution of dry deposition to total annual inputs of sulfur. Measurements of the deposition velocity ranne from 0.3 cm/sec to 1.25 cm/sec over soil, crop and other vegetation surfaces (Garland, 1978). These deposition velocities are substantially greater over vegetative surfaces during periods of maximum growth as well as during daylight periods. In order to estimate a dry deposition rate of SO 2 within the Poplar River Basin, conservative values for both the mean concentrations as well as deposition velocities were selected. Accordinoly, the annual mean concentration of SO 2 was taken to be 4.2 ig/ m 3 (the maximum annual average SO 2 concentration predicted by the CRSTER model for a 1200 MW power plant with zero percent S02 control). The selected deposition velocity (0.8 cm/sec) is the estimated value for day- light periods during the growing season. Based on these parameters the estimated annual dry deposition rate is 10.6 kg/ha S02 or 5.3 kg/ha elemental S. Wet deposition represents another mechanism for transport of atmos- phere sulfur to the soil. However, given the low levels of precipitation in the Poplar River Basin as well as the low ambient concentrations of SO 2 , expected sulfur inputs associated with precipitation would be less than dry deposition rates and will most likely make only a fractional contribution to total sulfur deposition. The underlying assumptions of the two estimates of annual sulfur deposition described above have a substantial effect on the predicted values (51.2 kg S/ha yr—i for a 1200 MW plant in the first estimate ver- sus 5.3 - 10.6 kg S/ha yr in the latter). The first estimate assumed 173 ------- 60 percent deposition within 40 km of the source. However, the rate of dry deposition (the most important source in semi-arid regions) in an area surrounding the emission source is related to the product of the inversion height and the ratio of the mean wind speed to the deposition velocity. Concentration decay distances of several hundred kilometers have been reported (Scriven and Fisher, 1975). The result of this sim- plified accounting of total deposition is a very conservative estimation of annual sulfur deposition on a per unit area basis. Sulfur can also be removed by cropping following plant uptake, by the leaching of soluble sulfates, and by surface drainage. For example, Likens, ai.. (1967) found that the loss of sulfur (9.8 k S/ha) in the drainacie for a catchment area in Flew Hampshire was approximately equal to sulfur inputs associated with precipitation (10 kg/ha). Plants them- selves provide a sink for sulfur emissions. A portion of the sulfur that is in a form available to plants during the growing season (the soluble inorganic sulfate, adsorbed sulfate) is assimilated by the vege- tation. As much as 50 percent of this organic sulfur can be removed from the system by cropping, while the remainder returns to the soil as organic material. This organic material again becomes available to the sulfate pool through mineralization, but this is a slow process and not rapid enouch to promote maximum plant growth. The nature of the soils also affects the degree of environmental impact. The soils in the Poplar River Basin are moderately calcareous; (average — 4 percent calcium equivalent on a weight basis, Smetana (per- sonal communication)). While soil acidification can be a problem in areas exposed to SO 2 emissions, the impact is minimized by calcareous soils (Flyborg, 1978). Based on the buffering capacity of soils in the impact area assuming a 4 percent CaCO 3 concentration, a soil depth of 50 cm, and the deposition of 50 kg/ha of elemental sulfur and the subse- quent conversion of this total amount of sulfur to H 2 S0 4 no significant change in soil pH would occur. Plume fumigation may occur during certain stable atmospheric condi- tions and result in the exposure of vegetation to substantially higher than usual concentrations of gaseous emissions. The estimated maximum exposure levels of S02 and N0 emissions are presented in Table 5.1-4. The estimated concentrations of NOx emissions are below reported thres- hold levels for exposures of short duration, but S02 levels expected to occur 10-20 km downwind of a 1200 MW plant during fumigation are within the lower limits of the threshold range associated with acute injury to sensitive vegetation. The concentrations of SO 2 expected to occur during fumigation under the most stable atmospheric conditions and maximum power generating capacity range between 1.0 and 1.5 ppm (Table 5.1-4), while concentra- tions associated with average meteorological conditions at Scobey are less than 0.7 porn (Table 5.1-5). These concentrations have been shown 174 ------- to cause foliar damage to some of the most sensitive plants when sub- jected to short-term exposure experiments; however, the sensitivity of these plants were determined in experiments in which the duration of exposure was one or more hours (U.S. EPA, 1973). The predicted fumi- gations are generally of short duration, persisting for periods up to 30-45 minutes (Portelli, 1975). Comparison of the estimated maximum S02 concentrations expected during fumigation with reported threshold limits of important native and cultivated plants found in the impact area (Table 5.6-1) indicate that the risk of S02 damage is minimal. During fumigation events vegetation will be simultaneously exposed to elevated concentrations of NOx, 03 and S0 . As an indication of the increased susceptability of vegetation to injury from combinations of gaseous emissions, a review of the literature (Linzon, 1978) found that a low concentration of 0.10 ppm SO 2 in combination with either 03 or NOx for periods of 4 hrs can injure a wide variety of plants. The problem with projecting impacts due to the synergistic effects of emis- sion gases based on values from the literature, however, is that the determination of threshold limits has been made at relatively long periods of exposure when compared to the duration of fumigation events. Examination of Table 5.6-1, for example, indicates a threshold level for hyslop wheat (Tritcurn aestivium) for 4 hr exposures at combined concentrations of 0.6 ppm and 0.1 ppm for SO 2 and NOx, respectively. While combined concentrations of S02 and NOx approximating these levels may occur as maximum ground-level concentrations during fumigation, the periods of exposure will be much less than 4 hours. Evidence to equate predicted gaseous concentrations during fumigations to established acute threshold levels was not found. - Factors other than temporal instability will also act to minimize the possibility for either losses in plant productivity or damage to vegetation in the impact area. The ground-level area fumigated during an inversion breakup is contained within a relatively narrow band be- neath the originally stable plume. At a distance of 10 km from the emission source, for example, the concentration of gaseous emissions is decreased by a factor of four at a distance of 500 m from the plume centerline and is less than 1 percent of the maximum concentration at 1000 m from the centerline. Moreover, the location of the plume fumi- gation is determined by wind direction. The chances of detecting fumi- gations, are very small unless the same area is fumigated repeatedly, and only a very restricted area is exposed to these higher SO 2 concen- trations during each event. Finally, the actual region within the impact area which will be potentially exposed to fumigation consists of a 10-km wide band between 10 and 20 km from the power plant and between the 1100 and 250° azimuths. 5.6.1.2 Particulate Emissions Based on the results of the air quality simulation model, it was concluded that no impacts on the terrestrial ecosystem would be ob- served as the result of direct contact with particulate emissions in 175 ------- the atmosphere. Projected increased ambient particulate concentrations are less than 0.4 .ig/m 3 (1200 MW plant with 99 percent control) within the impact area and, as previously indicated, meet both U.S. and Montana State air quality standards. Further analyses, however, were conducted in order to assess the possible long-term impacts associated with the deposition of trace elements and their subsequent accumulation within the food chain. Toxic levels of trace elements may accumulate in the tissue of plants indirectly by the uptake of soluble elements from the soil. It has further been shown that bioaccumulation of toxic concentrations of trace elements can occur at successive levels in the food chain follow- ing initial uptake and translocation by vegetation. The methodology used in the impact assessment of trace element deposition was similar to those utilized by Dvorak, etal., 1977. Accordingly, the following conservative assumptions were made in order to establish worse case projections: 1) The deposition of all emitted particulates occurs within a 80.5 km (50 miles) radius of the generation site. 2) The particulates are evenly distributed within the impact area. 3) Emission rates of trace elements are the product of the concentration of the dust collector ash and the estimated particulate emission rate (4899 kg/day). 4) All deposited trace elements reach the soil and are retained in the top 3 cm. 5) Trace elements move into the root zone and remain totally available for uptake by vegetation. These assumptions must be considered extremely conservative due to the physical characteristics of emitted particulates as well as the behavior of trace elements in the soil. Particulate emissions escap- ing 99.5 percent electrostatic precipators are very fine and exhibit a gas-like behavior. Vaughan, et al., (1975), for example, predicted that only 6 percent of the totaTeñiTssions would be deposited within a 50-km radius of their model plant. Additionally, while it is assumed that trace elements remain totally available to plant uptake and are readily transported to edible portions of the plants, available evi- dence indicates that the absorption and translocation of these elements are, in fact, limited by a number of factors. 176 ------- The projected percent increases in soil and aerial plant parts occurring over a 30-year period as well as the important intermediate calculations made in this analysis are shown in Table 5.6-2. Based on these results it is anticipated that the deposition of trace ele- ments will not have an adverse impact on the terrestrial ecosystem. The projected increased concentrations in the soil during the 30-year period are less than 0.20 percent for each of the selected elements. Moreover, the predicted increased concentration of trace elements in aerial portions of plants are below reported toxic levels summarized by Dvorak, etal., (1977). The projected increases in several trace element concentrations may also be compared with baseline concentrations in selected agricul- tural plant species reported by Braun, 1978. The ranges of concentra- tions measured in samples from 14 sites near the International Boundary are presented in Table 5.6-3. The tabulated concentrations of lead, cadmium, arsenic and selenium are for samples collected during the late summer of 1977. Samples were also collected in early summer, at which time most of the constituent concentrations were slightly less than or about equal to the late summer values. The notable exception is selenium, which displayed early-summer concentrations of 80-84 1g/g in grasses and forbs at two of the sites. A comparison of background trace element levels with predicted concentrations following 30 years of power plant operation indicates that there would be negligible increases in vegetation levels of the four measured elements. For example, the predicted increase in lead is only 10 percent of the lowest background lead concentration in grasses and forbs (0.20 pg/g), and represents only 2.4 percent of the corresponding maximum value. The percent increases above background are even less for lead levels in stems and heads of spring wheat. 5.6.2 Impacts of Atmospheric Emissions on Aquatic Biota Atmospheric emissions from the Poplar River Power Plant may poten- tially effect the following surface water quality parameters: acidity, nutrient availability and trace element concentrations. The potential for each of these effects is discussed in subsequent sections. 5.6.2.1 Acidification and Nitrogen Loading Emission of SO 2 and N0 may contribute towards increasing the acidity of local precipitation by the formation of strong acids. Sub- sequent reductions in the pH of surface waters may result if the natu- ral soil or water buffering capacity is low. Regional acid fication, presumably enhanced by combustion product emissions, has been observed in several areas of the world, including the Adirondack Mountain Lakes 177 ------- Table 5.6-2 PROJECTED DEPOSITION RATES, SOIL CONCENTRATIONS AND PLANT ACCUMULATION OF 17 TRACE ELEMENTS RESULTING FROM PARTICULATE EMISSIONS Increased Soil Increase Over Ti ace Element Concentration’ Avei aye Soil Tolal [ iidogeuious Plant Soil Increased Coi,c€,,t, at ic.i,s in Eii,i 551 on Rate Deposit ion (,iy/y) Cor ,cc ,,tr,, t ion Concenti at ions Co,,ceii tra tiori Pioi i a 1 Plant Pa ts 9/day g/iii /3Oy ar 3 cm 0eil. ___ J y/y)___ P ci cent Ratio’ Jp jL weiyh1)_ Lead 784 4.0 x l0 .9 x lO 10 09 2 0 02 tie, culy 0 441 2 37 a 10 5.4 x io 6 26 Pintiltiony 48 2 58 x 10 6 0 x 1O - - - - Cad i iium 1.18 6 35 a 1O 1 4 a 10 0 06 0 02 222 0 003 Silver 0 83 4 47 a 1O 1.0 x 10 - - - Seleiiium 1421 765 x i0 6 17 x 10 05 0.03 4 00007 Pirsenic 3625 195 a 10_s 442 a 10” 60 0007 42 0002 ue,riian ium 8 8 4.74 a io 6 1 1 a I0 - - - Zinc 122 5 6 59 a 10_s 1 5 a 10 50 0 003 40 0.06 Copper 181 3 9.76 a 10 22 x 10 20 0.01 1000 2.20 l ucI d 53 89 2 90 a 10 6 6 x l0” 40 .002 331 0 22 Cobalt 29 39 1 58 a 10 3.6 a 10 ” 8 .005 87 0 03 ManganeSe 2939 4 1 58 a 10 3.6 a io2 850 .004 3000 108 0 Ch,oiiiium 333 13 1.79 a 10 ’ 4 1 a 10 100 .004 250 1.03 Vai,ad,um 156 77 8 44 a 10 1 9 x 10 100 002 1 0.002 Boron 1469 7 7 91 a 10 I 8 a 10 10 0 0 18 Be iyliiurn 2 25 1.21 x 2 7 a l0 6.0 0005 16 0004 ‘As uiiies bulk density of soil is 1 47 9/cm 3 . ?TIIOSC concentration ratios were derived by Vaughn, eta). (1975) and express the potential uptake capacity of various plant species for indicated trace elenients ‘Ac unii: the concenttat lon of trace elements deposited in the top 3 cm of soil moves into the root zone and is totally available for uptake by the vegetation ------- Table 5.6-3 MINIMUM AND MAXIMUM CONCENTRATION OF TRACE ELEMENTS IN POPLAR RIVER BASIN VEGETATION (pGIG) SAMPLES COLLECTED DURING THE LATE SUMMER OF 1977 Pb Cd As Se Grasses and Forbs 0.20- 8.3 0.05-0.32 <0.05-0.17 <0.05-0.52 Spring Wheat - Stems 0.6 - 2.0 0.01-0.35 <0.05-0.20 0.08-0.38 - Heads 14.1 -67.6 0.01-0.16 <0.05-0.06 0.08-0.85 Alfalfa 0.2 - 1.0 0.05-0. 14 <0.05-0.08 0.07-0.35 179 ------- of Northern New York State. A regional analysis indicates, however, that there is an extremely low potential for surface water acidifica- tion in the Uorthern Great Plains (Dvorck, .i. , 1977). This re -- suits primarily from the alkaline nature of soils and surface waters, and the clay component of soils in the Poplar River Basin. Similarly, atmospheric NOx emissions are expected to result in no appreciable increase in N loading of surface waters which would result in increased eutrophication. The Upper East Fork currently displays indications of a eutrophic status based on inorganic nitrogen and phos- phorus concentrations and the abundant macrophyte growths. Based on observations by Klarich (1978) the Poplar River system is N-limited; therefore, increased inorganic nitrogen concentrations could poten- tially result in a concomitant increase in algal or niacrophyte growth. However, during the period of maximum potential plant growth (i.e., summer) atmosphere NO is generally not available for introduction into surface waters due to the lack of precipitation. Even during periods of heavy precipitation or runoff the transport of atmospheric inorganic nitrogen to surface waters would be minimal due to the low concentrations and utilization by terrestrial flora. 5.6.2.2 Trace Element Contamination A number of trace elements occur in flyash following coal combus- tion and are generally emitted in conjunction with the particulate matter. Mercury is emitted as a vapor, however. Trace elements emitted as stack discharges may eventually be in- troduced into streams, resulting in increased concentrations above background levels. The mechanisms and magnitude of transport into waterbodies are quite complex, however, and depend on the following factors: 1) terrestrial deposition rate 2) water flow characteristics (e.g., surface runoff or groundwater) 3) soil chemistry (especially CEC and pH) 4) aquatic chemistry (especially suspended solids, alkalinity, pH). In order to assess the potential for increased concentrations of trace elements in the Poplar River due to atmospheric emissions, the potential riverine concentrations were calculated using a simplified direct-transport approach. In estimating potential aquatic impacts, the following assumptions were used: 180 ------- 1) Sixty percent of the total particulate emissions would be deposited with the Poplar River drainage basin. 2) The total daily deposition of particulate matter would be dissolved into the average expected daily flow of the Poplar River. Due to the very conservative nature of the aforementioned assump- tions, the resultant estimates are actually the maximum potential con- centrations. The particulate emission rate was assumed to be 4898.9 kg/day, which corresponds to two 300 MW units with 99.5 percent elec- trostatic precipitators. Trace element concentrations in particulate emissions were assumed to equal the concentrations measured in dust collector ash of Poplar River coal samples (see Table 5.6—4). The results of these analyses indicate that the addition of trace elements derived from Poplar River Power Plant stack emissions would not result in appreciable elevations of background concentrations (Table 5.6-5). In most cases, calculated concentrations are consider- ably less than 1 ug/2. and represent only a small percentage of natural constituent concentrations. Moreover, when compared with Water Quality Criteria for the protection of aquatic life (EPA, 1976), the calculated increases do not result in any concentration (background and addition) exceeding the corresponding criteria value (Table 5.6-5). Trace elements can also accumulate in the snow and enter rivers as a slug during the spring but the concentrations would still not be sig- ni ficant. It should again be emphasized that the preceding calculations represent maximum potential values. The actual increases and potential effects on aquatic biota would probably be considerably less due to: 1) Much lower terrestrial deposition rates. Vaughn, eta]., 1975, indicates that only about 6 percent of particulates would generally be deposited within a 50—mile radius. 2) Retention of trace elements in soil will prevent groundwater or surface water contamination. The alkaline nature of Poplar River Basin soils and the moderate cation exchange capacity would tend to prevent groundwater transport. 3) Reduction of concentrations and toxic effects in surface waters. The solubity and resultant toxicity of heavy metals is considerably reduced in waters of high alkalinity and pH. 5.6.3 Impacts of Water Quality Changes on Fish and Wildlife Operation of the Poplar River Power Plant in conjunction with flow apportionment will affect downstream water quality in the U.S. part of the basin. Changes in a number of constituents have been predicted by 181 ------- Table 5.6-4 TRACE ELEMENT CONCENTRATIONS (PPM) IN POPLAR RIVER COAL ASH SAMPLES Upper Dust Ash Collector Ash Lead 110 160 Mercury 0.07 0.09 Antimony 5.6 9.8 Cadmium 0.24 0.24 Silver 0.17 0.17 Selenium 0.41 2.9 Arsenic 0.74 7.4 Germanium 0.91 1.8 Zinc 25 25 Copper 21 37 Nickel 7.5 11 Cobalt 5.1 6 Manganese 300 600 Chromium 170 68 Vanadium 48 32 Boron 100 300 Beryllium <0.10 0.46 Source: Accu—labs Research, Inc. (1978). 182 ------- Table 5.6-5 AVERAGE TRACE ELEMENT CONCENTRATIONS ( G/9.) IN THE POPLAR RIVER AND PROJECTED INCREASES DUE TO ATNIOSPHERIC EMISSIONS OF THE POPLAR RIVER POWER PLANT Input from Quality Criteria Median Maximum Atmospheric for Aquatic Life Criteria C.,ncen:ration’ Er issions 2 ( EPA. t975) Esti rate 3 Lead 2 5 1.6 0.01 96-h LC5O 2000 ercury 0 2.8 0.0009 0.05 Antimony - — 0.10 Cad iium <1 1 0.0025 12.0 Silver - - 0.0018 0.01 96-h LC5O Selenium <0.2 1.6 0.030 0.01 96-h LCSO 20 Arsenic 2 27 0.076 50’ Germamium - - 0.019 Zinc 10 30 0.259 0.01 96-h LC5O 50 Copper 1 9 0.383 0.01 96-h LC5O ‘ 50 Nickel 3 6 0.114 0.01 96—h LC5O “ 200 Cobalt — — 0.062 Manganese 60 200 2.69 1,5006 Chrcnium 0 10 0.704 100 Vanadium 1 5 0.331 Beryllium 0 10 0.048 1,100 Boron 1,000 4,100 3.11 18 x ‘Average for Poplar River from Klarich, 1978. 2 Based on daily dilution in average Poplar River Flow. ‘Based on reported toxicities in water quality similar to that of Poplar River. ‘io criterion for protection of aquatic life o criterion - domestic water supply criterion should protect aquatic life. 6 11o criterion - threshold for sensitive species. ‘ o criterion - lethal dose for minnows 183 ------- the water quality modeling studies outlined in Section 5.3. Several of these constituents have a high potential for direct impacts on aquatic biota. The effects of changes in thermal regimes, dissolved oxygen and dissolved solids are discussed in the following sections. Other con- stituents which are considered to be of very low potential for impact on aquatic life are also discussed in less detail. 5.6.3.1 Effects of Thermal Discharges The once-through cooling water discharge for the Poplar River plant is located near the reservoir release point at the dam. There- fore, there is a potential for heated waters to be released into the East Fork during reservoir spill or demand releases. The following section provides a discussion of the downstream temperature elevations and the potential for effects on aquatic life. The magnitude of temperature elevations (i T’s) downstream from Cookson Reservoir was examined by Spraggs (1977). The methodology used was a two-step modeling approach in which the thermal regime of Cookson Reservoir was simulated with both one- and two-unit operation (300 and 600 MW). The output of the layered one-dimensional reservoir model was then used as input into a fully mixed one-dimensional stream model to predict downstream Al’s from the dam to the International Boundary. The reservoir model indicated that for one-unit operation (at a plant AT = 18°F) the reservoir releases would be at a maximum AT of 9°F. For two units, the releases would be at the full power plant AT of 18°F. When these release AT’s are used in the stream model, a complete return to natural ambient temperature was predicted to occur within the Cana- dian part of the basin during the low-flow months of August through September. During June and July, an 18°F reservoir release (i.e., two 300 MW units) would result in temperature elevations at the Interna- tional Boundary of only 2.3°F (Figure 5.6.2). The greatest downstream effect on ambient temperature was predicted in May when a 9.2°F AT would occur at the boundary during an 18°F AT reservoir release. The modeling results are substantiated by using the surface heat exchange equation of Edinger, etal. (1975): TS = TN + TD_K(t ’ where IS = predicted temperature TN = natural temperature TD = temperature of reservoir release 184 ------- Source: Spraggs, 1977 Temperature Increase (°C) at International Boundary Figure 5.6-2 RIVER HEAT RELEASE SUMMARY 185 L) 0 a) U, a) I- a) a) S.- S.- a) E a) I— 10 8 6 4 2 0 1 2 3 4 5 6 ------- K = surface heat exchange coefficient A = area of river reach Q = flow This equation indicates that almost all of the heat will be dis- sipated prior to the International Boundary at flows of less than 100 cfs. The maximum predicted AT at the boundary is about 7.2°F, which corresponds to a flow of 250 cfs. Higher flows would result in greater heat dissipation due to increased water surface area resulting from overflow beyond the main channel. It should be emphasized that the May flow condition (130 cfs) re- sulting in the predicted 9°F increase at the boundary would generally be a rare occurrence under the proposed apportionment alternatives (see flows for Scenario 29 in Section 5.2). Under most conditions, the East Fork flow would be less than 100 cfs; therefore, the temperature dissi- pation would be considerably greater than predicted by Spraggs (1977). The modeling results indicate that the only potential for signifi- icant downstream temperature elevations in the U.S. part of the basin would occur during high runoff conditions in the spring. The potential effects would be considerably moderated, however, since the reservoir would not usually have a natural spill during April—May, demand releases would generally be less than 100 cfs and cooler ground water would also enter the river downstream of the reservoir. Although it is considered unlikely that significant temperature elevations would occur in the U.S. part of the basin, it is an impor- tant consideration due to the occurrence of gamefish spawning activi- ties during high flow conditions. Eggs and larvae may be especially susceptible to temperature changes. Therefore, recruitment to walleye and northern pike fisheries is dependent on a given thermal regime during incubation and juvenile development. Egg and larvae data collected by Montana Department of Fish and Game (1978) indicate that, during the spring of 1977, walleye and northern pike were probably spawning during the period of mid-April to early May. During the spawning period median daily river temperatures ranged from about 48° to 59°F. Daily temperature variations were quite high and ranged from 8 to 12°F. Larval walleye occurred in the river until mid-May, at which time natural river temperature ranged from 55° to 70°F. Studies by Koenst and Smith (1976) on the temperature requirements of young walleye indicate that optimal temperatures for egg incubation range from 48.2° to 59.0°F. This temperature range closely corresponds to the observed occurrence of ripe adults and larval walleye during 1977. The young walleye were also quite resistant to temperature 186 ------- changes since they tolerated up to a 18°F AT over a period of 72 hours without adverse effects on survival. The high resistance to rapid temperature fluctuation by young walleye was also demonstrated by Ailbaugh and Manz (1964). In the laboratory studies there was also good survival to hatch of walleye eggs incubated at temperatures up to 64°F, indicating that relatively small increases in natural river temperature during the spawning season would not adversely affect sur- vival. The optimal temperature for growth of juvenile walleye was about 72°F (Koenst and Smith, 1976). The upper lethal temperature ranged from 81 to 89°F as acclimation temperature increased from 46° to 79°F. These data indicate that small elevations in ambient river temperature (<6°F) during the juvenile rearing period would also not be detrimental to walleye production. Conversely, it could be potentially beneficial since ambient river temperature during much of May are actually sub- optimal for walleye growth. This is an important consideration since Johnson (1961) found that cold weather during the incubation period may actually be an important limiting factor in determining walleye year- class strength. Based on available data for young northern pike (Hokanson, etal., 1973), it appears that their temperature tolerances would also not be exceeded by small temperature elevations (<6°F) in downstream areas. Pike larvae are apparently more sensitive than walleye to rapid temperature changes. However, in field studies Franklin and Smith (1963) found good survival when temperature changes did not exceed 1.2°F/hour. Furthermore, the upper lethal thresholds (96—hour) for both northern pike and walleye are about 90°F. Since the maximum natural river temperatures are generally about 80°F, limited heating (<5°F) of the river during summer would not exceed the upper limits for gamefish survival. In summary, mathematical predictions indicate that the downstream temperature elevations due to power plant operation on the Poplar River are a function of: • number of units • flow in East Fork For the two-unit operation (600 MW) the maximum predicted temperature elevation at the boundary during expected spring and summer flows would be less than 2°F. Moreover, during low flows all excess heat would be dissipated prior to the International Boundary. Even under situations of high flow (>130 cfs) the maximum excess AT at the border would be 187 ------- only about 9°F, and this would undergo rapid decay in the East Fork. Therefore, even under the most extreme situations (i.e., two-units and high flow) the natural stream temperatures would probably be reached within the East Fork. The available information on the thermal re- quirements of the two major game fish present in the Poplar River indi- cates that there would be no adverse impacts due to thermal releases at the reservoir. 5.6.3.2 Effects of Dissolved Solids Increases Increased total dissolved solids (TDS) levels in freshwaters may be potentially toxic to aquatic life. Tolerance of fishes to increased TDS is highly variable according to species; however, it is generally assumed that TDS concentrations above 5,000 to 10,000 mgI2. would gen- erally represent adverse conditions for survival of most freshwater organisms. It should be emphasized that most freshwater species, especially those inhabiting the Northern Great Plains waters, can tolerate a relatively wide range of TDS concentrations. This is necessary due to the high seasonal variability encountered in many surface water bodies. For example, in the Poplar River, natural TDS concentrations may range from <150 mg/9 .. during high runoff, to over 1000 mg/Z during low flow conditions. In general, the early life stages of fish (i.e., eggs and larvae) are more sensitive to increases in TDS than adults of the same species. Limited data are available on the salinity tolerances of eggs of the two major species of Poplar River garnefish: walleye and northern pike. PeterLa (1972) reports that eggs of both species displayed good hatch- ing success in waters with a conductivity of 1300 pmhos. Based on the conductivity - TDS relationship of Poplar River waters at 25°C, this would represent a TDS concentration of about 1100 mg/9. . As the conduc- tivity was increased to 4000 imhos (TDS 3500 mg/2 ). There was no hatch of walleye eggs and very poor hatch of northern pike. The studies of Petarka (1972) also indicated that fathead minnows (a for- age fish in the Poplar River) experience no adverse effects on growth and reproduction at TDS concentrations up to 7000 ng/2 . The water quality modeling results indicate that the highest potential for increases in TDS concentrations resulting from flow apportionment will occur in the Upper East Fork (see Section 5.3.3). With more than two units (1985 and 2000 level of development) the April TDS concentrations in the entire East Fork will be at levels where spawning of walleye and northern pike may be impaired in one year out of every ten (i.e., 90 percent concentration is exceeded). During 90 percent of the spawning seasons the egg tolerance limits should not be exceeded in the East Fork. In all other parts of the U.S. basin, TDS concentrations during April should be below the toler- ance levels for successful hatch of gamefish eggs. This results from dilution by lower salinity waters from the West and Middle Forks. 188 ------- The only condition which results in TDS concentrations exceeding the limits for maintenance of fish population during the non-spawning season is with four units at the year 2000 level of development. In such cases relatively high TDS concentrations (4000-5000 mg/9 ) would exist in the East Fork during low flow months in the fall and winter. Although such concentrations would probably be toxic to gamefish, the more important limiting factor under Scenario 32 would be the absence of flow in the lower East Fork (see Sections 5.6.4). 5.6.3.3 Effects of Dissolved Oxygen Changes Adequate dissolved oxygen is essential for the maintenance of fish populations. This is especially true for gamefish species such as those existing in the Poplar River, which are generally less tolerant of low oxygen levels than “rough” or forage species. There are two main conditions in which dissolved oxygen may be limiting factors for the production of stream fish populations: 1) During the spawning period eggs and larvae may be susceptible to low oxygen levels, especially in species which deposit eggs in the bottom substrate. 2) In areas where surface waters freeze during the winter, low dissolved oxygen conditions may exist, especially in shallow waters at low flow rates. Based on recent Quality Criteria for Water (EPA, 1976), a minimum dissolved oxygen concentration of 5 mgR is recommended for the mainte- nance of “good” fish populations. Based on available water quality data, it appears that dissolved oxygen levels in the Poplar River are well above minimum values for gamefish protection during the period of April through November. Even in the upper reaches of the East and West Forks, the dissolved oxygen always exceeded 86 percent saturation. Moreover, these high levels were measured after closure of the dam on the East Fork; therefore, during ice-free conditions no adverse impacts of apportionment schedules on dissolved oxygen concentrations are ex- pected to occur. Dissolved oxygen levels also appear to be sufficient for success- ful spawning and early development of walleye and northern pike. Oseid and Smith (1971) indicate that the lowest dissolved oxygen concentration for optimal hatching of walleye eggs is 5-6 mg/L Moreover, a relatively high survival to hatch was observed at dissolved oxygen concentrations of only 2 mg/2 .. Hatching time was extended, however, and the larvae were smaller at hatching when incubated at 2 mg/Z. Siefert, etal. (1973) found similar results for northern pike eggs and larvae. Dissolved oxygen concentrations of about 5 mg/2. were ade- quate for hatching and survival to the feeding stage. Pike eggs may be 189 ------- more sensitive to continuous lower oxygen concentrations since survival was considerably reduced at a level of 3.4 mg/9 . However, pike larvae are apparently able to tolerate short exposures to low dissolved oxygen concentrations. Peterka and Kent (1976) found no reductions in survival of embryos, yolk-sac larvae and larvae maintained for eight hours at dissolved oxygen concentrations of 0.6, 2.0 and 4.0 mg/9.., respectively. Since April dissolved oxygen concentrations in the East Fork after dam closure (since October, 1975) are generally above 5 mg/2 ., no impacts on fish spawning due to changes in dissolved oxygen levels are antici- pated. This conclusion is based on the observed high spawning-period oxygen concentrations under spring flow conditions on the East Fork which are more severe (in regard to flow and oxygen availability) than would be expected under the apportionment agreements. This results primarily from the additional demand releases which would add a minimum of 1 cfs to the natural flow resulting from groundwater accretion and surface runoff. During the period of normal ice cover on the Poplar River, low dissolved oxygen may be an important limiting factor in fish survival. In February-March, 1977, Stewart (1978) observed large numbers of dead walleye, suckers and carp on the East Fork. In late February, dissolved oxygen concentrations as low as 0.1 mg/9 .. were recorded under the ice. Moreover, in some locations there was no water below the ice or the ice depth exceeded 4.5 feet. This lack of available under-ice habitat and low oxygen levels was apparently the cause of the fish kills. Similarly low oxygen levels were observed on the West Fork and, in conjunction with the low summer flows, may explain the lack of gamefish in that part of the basin. Based on the aforementioned considerations and the historical occurrence of very low flows during January and February, it appears that during years of average or low flows the apportionment of flows and resultant continuous demand releases (1 or 2 cfs) will have a po- tential beneficial effect on fish winter habitat. As indicated in Section 5.2, the flows on the Upper East Fork at both 10 percent and 50 percent frequency will be greater than the corresponding historical flows. Oxygen concentrations in the East Fork during the previous winter (1976-77) (Stewart, 1978) appear to be satisfactory for fish survival (e.g., >4 mgI2 .). The average winter flows in 1976-77 (1.7-2.3 cfs) were similar to the median winter flows under development Scenarios 28 through 32. There are also no anticipated adverse impacts on winter fish habitat in the Middle Fork due to the apportionment. During January and February there is historically little flow at the International Boundary of the Middle Fork or its major tributary, Coal Creek. There- fore, during the winter most of the flow in the Lower Middle Fork has occurred in the U.S. part of the basin below the confluence of Coal Creek. This is true under historical conditions and under Scenarios 190 ------- 28 through 30 (i.e., up to three units at 1985 water use). Scenarios 31 and 32 (3 and 4 units at 2000 water use) include a reservoir on the Middle Fork and median (50 percent) or low (10 percent) winter flows would actually be larger than historical flows in the Lower Middle Fork. In summary, the apportionment schedule which results in the main- tenance of stable winter flows in the East Fork will not adversely impact fish survival in winter and should have a beneficial effect in preventing the occurrence of fish kills during low—flow years. 5.6.3.4 Other Constituents Maximum concentrations of boron up to 20 mg/2 could occur in the Poplar River under the apportionment agreement. No impacts on local fish and wildlife are predicted, however, due to the relatively low toxicity of this constituent to animal life. Toxic concentrations to fish are over 1000 times the osmosis predicted concentrations. Turbidity and suspended solids measurements on the Poplar River indi- cate that this constituent is not limiting to fish production. Even during extreme high flow conditions the suspended solids are within short-term tolerance ranges. Any effect of power plant development on the East Fork would probably be evidenced as reduced suspended solids loading due to settling in Cookson Reservoir. Therefore, no adverse impacts of development would be predicted. 5.6.4 Impacts of Flow Modifications on Fish and Wildlife 5.6.4.1 Wildlife and Furbearers Several species of mammals and birds are directly dependent on the aquatic habitat provided by the Poplar River. The two main groups which have a potential for impact from flow modifications are furbearers and waterfowl. Both of these groups require specific aquatic habitat characteristics which may be modified by variations in the amount of water available in the river basin. During the period from 1977 to 1978 the number of observations of beaver and raccoon in the Poplar River drainage increased slightly. At the same time, the observations of muskrat decreased, while the numbers of mink remained unchanged (DeSimone, 1979). It is generally believed that beaver, muskrat and min’k populations have declined during the last 30 years primarily as a result of intensified agriculture and land use practices in the area. It is not anticipated that the proposed action will have an adverse impact on furbearers, since they are not directly dependent upon the magnitude of peak flows. 191 ------- Inability to maintain existing channel morphology in the upper nine miles of the East Fork due to reduced flows may result in encroach- ment of emergent macrophytes and a concomitant loss in waterfowl pro- duction. Recent studies (DeSimone, 1978) have shown that both waterfowl breeding pair density and production was greater in this portion of the East Fork than on similar areas studied on the Middle Fork, Main River, West Fork, Coal Creek and Butte Creek. While it was concluded that existing submergent and emergent macrophyte growth provided brood cover and was responsible, in part, for the greater brood production in the upper portion of the East Fork (DeSimone, 1979), substantial in- creases in emergent growth would result in the loss of brood habitat by restricting access to the preferred rearing grounds for surface- feeding species of ducks. It has been shown that a greater than 50 percent areal coverage of emergents on a water body renders these areas unsuitable for duck production (Evans and Black, 1956; Stoudt, 1971; and Whitman, 1976). In an assessment of the effects of altered flow regimes of the Poplar River, Bahis (1979) stated that flow reductions with two power plants and the recommended apportionment will result in an expansion of the macrophyte community within the system. It was concluded that mac- rophyte growth within and along the main channel will be most dramatic in the East Fork and may result in 50 percent coverage during the life of the project. The results of an aerial survey of emergent vegetation in several segments of the East Fork Poplar River during July 1979 (DeSimone, 1980) indicated that at least in the area adjacent to the International Boundary one section is approaching 50 percent coverage, while emergent coverage in three other sections ranged from 5.8 to 21.6 percent. However, additional releases specified under the recommended apportionment were not made. Based on the relationship between areal coverage of emergents and waterfowl production presented above additional encroachment in the uppermost reaches of the East Fork will result in a reduction in waterfowl production. Progressive encroachment in the upper nine miles of the East Fork Poplar River resulting in greater than 50 percent areal coverage would result in the loss of approximately 70-80 breeding pairs of ducks and the production of between 300 and 400 ducks annually (DeSimone, 1979). However, simultaneous increases in macrophyte growth in the lower East Fork and Main Poplar River, where abundances of emergents are substantially less than the upper East Fork, could lead to an increase in waterfowl production in these areas and the supplanting of the breeding areas to the north. 5.6.4.2 Fish The fish populations of the Poplar River are susceptible to habitat alterations resulting from changes in river flow rate. The two major areas of potential impact are: • Changes in spawning habitat • Reduction in overwintering habitat 192 ------- The impacts of flow modifications resulting from apportionment on the winter survival of fish during ice cover conditions are related pri- marily to the low dissolved oxygen concentrations occurring under low flow conditions in January and February. These impacts are discussed in the water quality section (5.6.3.3). The main emphasis of this discussion will involve consideration of the flow impacts on spawning habitat for the two major game fish species in the Poplar River: walleye and northern pike. Although the magnitude of flows during non-spawning seasons may also be potentially limiting to game fish production, no adverse impacts of apportionment are expected due to the continued observed occurrence of gamefish (Stewart, 1978) during low flow years such as 1976-77. In such cases measured flows throughout the basin were less than those predicted under the most likely apportionment alternative (VI). Therefore, subsequent impact discussions will be concerned with three main aspects of fish spawning habitat: 1) Maintenance of normal channel morphology 2) Inundation of shoreline vegetation 3) Prevention of siltation Both northern pike and walleye normally spawn during April in the Poplar River. Although their spawning seasons coincide, they require quite different spawning habitats. Pike deposit adhesive eggs among vegetation in shallow water (<15 inches deep). The eggs hatch in about 2 weeks. Walleye spawn over gravel bottoms in pool tails or riffles (depth usually less than 1.5 feet). Their adhesive eggs settle into the gravel and also hatch in about two weeks. Walleye are an important game fish in the Poplar River and their continued existence in a prairie stream such as the Poplar River is dependent upon the maintenance of the existing channel morphology consisting of alternating riffles and pools with clean gravel substrate during the spring. Alteration of the morphology of the Poplar River to that of a more typical prairie stream (e.g., uniform gradient, soft bottom) would result in a loss of walleye production. Therefore, it is important to consider the flow regimes required to maintain the current degraded channel. The hydraulics of the Poplar River are complex. The bed character- istics and meandering channel form make velocities at any transect extremely non-uniform. The abruptness with which flood peaks occur make velocity computation by steady-state hydraulics equations inexact at high flows. However, these are the important flows from the stand- point of maintaining fish habitats in certain portions of the river. 193 ------- Therefore the actual numerical estimates made in this section to pro- vide a flow and sediment characterization of the East Fork may be considerably in error. However, the numbers do reveal some general relationships such that conclusions can be drawn concerning impacts of flow on fish. In order to determine if the Poplar River can maintain the degraded channel appropriate for spawning, two questions must be answered. They are: • What flows produce the tractive forces required to suspend sediments, and • What duration of the critical flow is necessary to scour the sediments. Flow uniformity in the channel must first be assumed. This will necessarily underestimate the scouring potential over the riffle areas and overestimate in pool areas. If pools occur in bends of the river, radial acceleration may keep the scouring rates competitive with those in riffle areas. Brown (1978) conducted a study to determine minimum flow rates for maintenance of fish habitats. In the investigations he collected the particle size data shown in Table 5.6-6. The data are broken down into riffle and pool areas. In general, velocities are lower in pools and finer sediments tend to collect in those areas. To maintain the spawning habitat of game fish on the East Fork, it is necessary to scour the size fractions from approximately the medium sands to the colloidal clays. The velocities required to pick up and transport these particles range from about .52 to 1.04 feet/second. (Longwell, et al., 1969). The approach to finding the critical flow required on the East Fork included the use of the Manning formula. This equation, v = n R” S’ says that the average stream velocity (V) is proportional to the stream hydraulic radius (R) and the energy slope (S) and inversely proportional to channel roughness (n). Since the critical velocity (1.04 fps) is known, the equation can be rearranged to calculate R. The roughness coefficient (n) was taken from Schwab, etal., (1966) and has a range of 0.45 to 0.6 from streams like the Poplar. S was found by dividing the difference in elevation of the USGS stream gauge at the International Border and the gauge near Scobey on the East Fork by the total estimated distance in river miles between the two locations. The value of S used was 0.00011 ft/ft. Using these values yielded a hydraulic radius R and, assuming a rectangular channel, a new flow depth was calculated as 194 ------- Table 5.6-6 BED MATERIAL SIZE DISTRIBUTION Sample Pool(P) D 036 D c 084 09 Loca tion Ri ffle(R) (ni ) (mni (nin (mmj (n im (nm) (n m East Fork 2.5 miles below P 0.058 0.095 0.11 0.15 0.18 0.25 0.4 Inter. Border R 0.6 4.0 12.5 21 31 39 45 Cromwell Slab P 0.34 1.6 7.6 12.5 21 46 57 R 2.7 10.25 20 36.5 52 73 84 USGS gage P 0.27 1.0 4.8 9.1 16.5 31 49 near Scobey R 0.5 1.8 8.5 14 22 39 49 Middle Fork McCarty Crossing p i.i 8 19 33 45 63 80 (J1 near mt. Border R 2.1 11 21 33.5 39 49 58 Hagfeldt Slab P 0.21 0.37 6.6 21 39 56 62 R 0.92 8.3 18 26 45 54 58 Ofstedal Slab P 0.18 0.255 0.30 0.345 0.44 0.79 1.20 R 4.7 10.5 19.5 28 37 68 75 West Fork South of Peerless P 0.35 4.3 10.0 15.5 20.5 39.5 54 P 4.2 10.5 25.5 48 68 79 86 Susag Farm P 1.4 10.0 30 40 51 66 68 R 0.32 1.8 7.6 14 32 56 68 Main Stem P 0.062 0.099 0.135 0.165 0.21 0.33 0.45 R 0.31 1.4 8.0 15 22 41 48 Crowley Slab P 0.54 0.086 0.128 0.196 0.31 0.38 0.45 R 0.30 1.6 10.0 17 24 47 52 Source: Brown, 1978 ------- depth = w R where w is the width of the stream (from the Brown (1978) data). Know- ing the new depth and channel width, the cross-sectional area can be calculated. The critical flow required to flush sediments from the fish habitats was computed by continuity (Q AV) to be about 715 cfs. The flow required to overtop the main channel and begin inunda- tion of the shoreline vegetation areas is somewhere between 220 and 330 cfs according to similar calculations. This range of values is supported by the report of Saskmont Engineering (1976) who indicated that a 250 cfs flow would escape the main channel. Therefore at flows which would provide the required scouring velocities the pike spawning habitats would be inundated. Calculating the duration of the required 700 cfs scouring flow is a more difficult problem. The first assumption that was made in this solution was that the reservoir is a 100 percent effective sediment trap for waters spilling from the upper East Poplar across the International Boundary. Secondly, it is assumed that sediment loadings to the river (excepting the within channel bank erosion) come only from cultivated agricultural land. Using the universal soil loss equation, the annual sediment loads from cropland to the East Fork can be obtained. The equation is: A = RKLSCP where A is the annual sediment loss in tons/acre R is the rainfall erosivity factor K is the soil erodibility factor LS is the slope-length factor C is the crop factor, and P is the practice factor. The parameters were estimated from tabulations and figures in Stewart (1976). The parameter values are given below. R = 50 K = .30 (for a sandy clay to silt loam soil) LS = .20 (slope length 1000 ft, .05 percent slope) C = .13 (spring wheat) P = .52 (fall seeded grain, low slope) Using these parameters the gross erosion is about 0.20 tons/acre. Zison, etal. (1977) has presented the relationship developed by McElroy to determine the sediment delivery ratio. Using the drainage density given for the East Fork and the proper soil type, this ratio is deter- mined to be 0.12, yielding a net delivery to the stream of 0.024 tons/ acre. The contributing area to the portion of the East Fork from the 196 ------- International Boundary to the USGS gauge near Scobey is approximately 188 mi 2 . Of that, about 74 percent is under cultivation, or about 89,000 acres. This indicates an annual sediment loading in the U.S. portion of the East Poplar of 2136 tons. This, of course, assumed that loadings from uncultivated areas are negligible and that no loads are added in between the reservoir and the U.S. boundary. To estimate the scour at the critical flow rate, sediment concen- tration and flow data were taken from USGS records for the East Fork at the International Boundary. The suspended sediment data were converted to mass flux data and plotted versus flow rate. This plot is shown in Figure 5.6-3. A log-log least squares regression gave the best fit line shown in the figure. The equation for sediment flux in grams/seconds given flow in cubic feet/second is: Flux = 1.16 (Flow) 0 97 Substituting 715 cfs into the above, the sediment flux is calculated to be 680 g/sec. This represents the amount of suspended sediment that would move past a point in the river in one second at that flow. If the assumptions are made that the only sediment in suspension comes from overland flow loading and that sediment must be transported through the entire length of the reach, then the time required to flush the East Fork would be 33 days. Realistically, the sediment probably does not need to be moved entirely through the system in order to cleanse critical areas. The spawning habitat in riffles is probably maintained due to the movement of sediments off riffles into more sluggish areas of the stream. These areas are usually where point bars are building up on the inside of bends. Therefore, the 33 days is a nominal upper limit value. According to Brown (1979) the average distance between areas of severe bank cutting and hence the distance between corresponding sluggish areas on the inside of the turns is about 2,000 feet. If sediments are only required to move this distance, the duration of the 700 cfs flow would necessarily be only about 6 hrs. Very likely, the time required for scouring is between these limits. For instance, the clays may move entirely through the system while coarse sands may be picked up and deposited 2000 feet downstream. Fine sands might travel several miles and come out of suspension. If the outlet pipe of the reservoir could produce the required 715 cfs, the duration of such a flow (assuming half the total reservoir storage could be utilized) would be only 11.5 days. If the 300 ac-ft under the apportionment schedule were released at this rate the flow duration would be only five hours. It seems infeasible that the habitat can be maintained with the reservoir in place. However, his- torical records indicate that the mean monthly flow in the East Fork 197 ------- 1000 Flux 1.16 (Flow) 0 97 r 2 85 log-log 0 Prereservolr (1974 - Nov 1915) Postreservoir (Dec 1915 - 1976) 0.1 0.1 1 10 100 1000 Flow (cfs) Figure 5.6-3 SEDIMENT FLUX VERSUS FLOW AT THE INTERNATIONAL BOUNDARY EAST FORK POPLAR RIVER * U QJ a. U- 4-. a) E a) €1) 0 a) -a C a) U . U) 100 10 1 0 0 Do 0 0 0 0 0 0 ------- is never sustained above 715 cfs. It is very likely, then, that burgeoning agricultural development over the past century has caused a slow aggradation of sediments in the East Fork. The following dis- cussion illustrates this. The sediment loadings to the East Fork appear to be quite small. The U.S. East Fork from the International Border to the USGS gauge at Scobey is approximately 100 feet wide during high flow on the aver- age. Sediment with voids weighs about 165 pounds per cubic foot. Using this information, the mean annual depth increase of sediment on the stream bed can be estimated. This depth is 0.00069 ft/year. At this rate, 120 years would be required to accumulate a one-inch depth uniformly over the East Fork (assuming bank cutting is a negli- gible source). If siltation occurs as a result of reduced flows, it will likely be a very slow process. Analysis of historical records indicates that on the upper East Fork the peak discharge with a return period of 2 years is 948 cfs. Although it would occur normally for only a short period (e.g., <2 days), peak flows of this magnitude have obviously been sufficient to main- tain adequate spawning substrate for walleye. Since the water quantity modeling results are based on total monthly flows, it is difficult to predict the exact effects of appor- tionment on the magnitude or duration of peak flows which may occur for short periods only. However, it is reasonable to assume that peak flows on the East Fork are considerably reduced when compared with pre-impoundment conditions. Since the demand releases would be insufficient to affect significant scouring, it must be concluded that the long-term effects of power plant operation and flow apportionment will be a gradual change in channel morphology, especially in the East Fork. These changes would eventually result in an adverse impact on the availability of walleye spawning habitat in the form of riffles with clean gravel bottoms. Several factors suggest, however, that the adverse impacts on walleye spawning habitat may not be manifested for some time after initiation of power plant operation and flow apportionment: • Low sedimentation rate. Reservoir construction has actually reduced sediment load in the East Fork due to sedimentation in the reservoir and reduction in bank erosion due to lower peak flows. • Continued spawning on East Fork after closure of Morrison Dam. Flows on the East Fork during the last two spawning seasons (1977 and 1978) have been approximately equal to, or less than, median flows predicted to occur with one power plant unit in operation. Although poor spawning occurred in 1977, a good year class of gamefish was apparently pro- duced in the East Fork in 1978. 199 ------- The spawning success of pike and walleye (Stewart, 1978; Stewart, 1979) during the last two years will be examined in further detail in order to predict effects of stable flows during April on gamefish spawning success. These data are important since they were collected after closure of Morrison Dam and two quite different flow regimes were represented: an extremely low flow period in April of 1977, and a higher flow in April of 1978 which was, however, still below average for the historical period. During both years walleye and northern pike in spawning condition were found in all three Forks and in the main Poplar River. In the low flow year of 1977, there was an apparent failure of the walleye year class on the East Fork. In April of 1978, there were many more larvae of both walleye and pike collected, indicating increased spawning success when compared with 1977. The East Fork station referred to as Cromwell had the highest mean density of walleye eggs per sample when compared to all other 1978 sampling stations. More- over, in 1978 numbers of young-of-the-year walleye per mile on the Ea t Fork increased to about 13 times the densities measured in 1977. Over the entire river basin 1978 densities of young-of-the-year walleye were approximately double the 1977 densities. There was also apparently a successful 1978 year-class formation of northern pike on the East Fork as evidenced by the occurrence of ripe spawners and young-of-the year fish. It must be emphasized, however, that there are no actual baseline evaluations of normal fish spawning in the Poplar River. Therefore, although 1978 was a good year for year class formation, it may have actually been less than the potential production under optimal flow conditions. All of these data indicate that the April, 1977, flows on the East Fork were not sufficient for successful gamefish spawning, while the flow regimes in 1978 were adequate for the formation of a good year class. The conclusion regarding the relative success of the 1978 East Fork spawning of walleye is further substantiated because there probably was a reduced spawning population due to winterkill. The large mortal- ity of walleye observed in that area during February and March was due to low dissolved oxygen concentrations below the ice cover (Stewart, 1978). Thus, the spawning success might have been even greater with a normal size spawning population. Pike typically spawn among submerged vegetation during high flow or flood conditions. Several studies indicate that pike prefer sub- merged terrestrial vegetation such as native grasses, mowed hay or wheat stubble for spawning substrate (McCarraher and Thomas, 1972; Forney, 1968). Others have found, however, high utilization of sub- merged plants such as Myriophyllum (Frost and Kipling, 1967) or emergents such as sedges or rushes (Franklin and Smith, 1963). Appar- ently, flooding beyond the primary channel is not necessary for success- ful pike spawning in the Poplar River. This is evidenced by the 200 ------- occurrence of a peak flow of only 80 cfs during April of 1978. In order to overtop the main channel in the East Fork, a flow in excess of about 200 cfs would be required. Examination of the flow data presented in Table 5.6-7 reveals that during 1977 the East Fork experienced very low flow conditions. The East Fork April flows at the border and Scobey stations were considerably less than (‘ 50 percent) natural or historical 10 percent frequency flows (Table 5.6-8). Moreover, peak April flows reached only 11 cfs. This condition probably resulted from a combination of an extreme low runoff year and the blockage of flow at Morrison Dam. The 1977 Middle Fork flows at the border were relatively higher since there is no impoundment on that Fork. The April flows were about 20 percent higher than the 10 percent frequency flow on an historical basis. The April, 1978, East Fork flows (average and peak) at the International Boundary were approximately equal to the 1977 measure- ments. However, flow accretion in the U.S. East Fork sub-basin resulted in higher peak and average flows in the lower East Fork near Scobey than occcurred in 1977. These comparisons indicate that average spawning-period flows of 2.4 to 6.6 cfs are not adequate for successful game fish spawning in the Poplar River. However, as the average flow in the same river reach increased to 2.7 to 24.5 cfs, a good year class was formed. During the successful spawning period, peak flows ranged from 3.3 to 80 cfs, while the poor spawning period was characterized by peak flows of 2.9 to 11 cfs. Comparison of 1977-78 East Fork flows with predicted flows under apportionment reveals that the measured 1978 average April flows were only slightly higher at Stations 1 and 3 than the predicted flows under scenario 29 (i.e., 2 units at 1985 water use)(Table 5.6-8). Therefore, with up to two power plant units, the walleye and pike spawning on the East Fork should be approximately equal to the 1978 level of success with a return period of 2 years. However, in one out of ten years with one or more units in operation, the April East Fork flow would average only 0 to 4.3 cfs, resulting in severe adverse effects on game fish reproduction. Based on the observed spawning- flow relationships in the East Fork, it is expected that the flow apportionment has a lower potential for adverse impact on fish spawning in the main river and middle forks. However, the apportionment will also affect flows in the main river and long-term effects on stream morphology may occur. 201 ------- Table 5.6-7 COMPARISON OF 1977 AND 1978 SPRING FLOWS (cfs) AT SELECTED POPLAR RIVER STATIONS STAT ION East Fork at Border East Fork at Scobey Middle Fork at Border Main River at Poplar Peak Average Peak Average Peak Average Peak Average r- . ‘ — a — MARCH APRIL MAY 5.8 2.9 58 2.6 2.4 13 22 11 164 8.3 6.6 17.9 15 15 82 9.5 11.1 12.4 168 210 42 112 122 31.3 • MARCH APRIL MAY 6.2 3.3 3.9 3.6 2.7 3.0 220 80 10 69.7 24.5 6.1 829 709 56 225 75.4 25.6 4610 4630 205 1163 640 150 .-4 APRIL MAY 270.0 139.0 143.0 43.9 - - - - 1620 155.0 325.3 59.7 - - - - ------- Table 5.6-8 PREDICTED AVERAGE APRIL FLOWS (cfs) IN THE EAST FORK POPLAR RIVER PERCENTILE Scenario 90 50 10 Station 1 East Fork at Border 1 2 28 29 32 308 301 270 249 63.3 28.6 28.6 11.4 2 2.2 7.7 7.1 1.0 1.0 1.0 Station 3 East Fork near Scobey 1 2 28 29 32 492 -- 437 398 221 48.0 48.4 23.0 20.4 17.7 13.7 -- 4.3 2.2 0.0 203 ------- Recent fish data collected by Stewart (1980) provide further evi- dence for the influence of streamfiow on spawning success of walleye and northern pike in the Poplar River. In 1979, there was above average runoff in combination with spring releases from Cookson Reservoir. The 1979 average April flow at the East Fork Border station was 143.0 cfs, compared to 1977 and 1978 flows of 2.7 and 2.4 cfs, respectively. The higher 1979 flows resulted in the formation of strong year classes as evidenced by high densities of 0+ walleye and northern pike in the East and Middle Forks. The relationship between spring flow and year class recruitment for the period 1977-1979 is diagrammed in Figure 5.6—4. Abundances of young-of-the-year walleye and northern pike at downstream stations show a positive correlation with mean April flow near the border in both the East and Middle Forks. Coefficients of determination (r 2 ) for the wall- eye and northern pike were 0.84 and 0.73, respectively. Although these data were from two different river sub-sections, and some data are esti- mates due to low collection numbers, they do provide an indication of the strong relationship between flow rate and year class recruitment for both species. Flow appears to be a stronger predictor for young walleye sur- vival than for northern pike as evidenced by the corresponding r 2 values. In addition, the slope of the walleye data (82.29) is considerably higher than that for northern pike (35.23). Therefore, as mean April trans- boundary flow increases from 10 to 100 cfs the predicted density of young- of the year walleye increases by 190/mi, while predicted northern pike density increases only about 80/mi. Comparison of 1977-1978 East Fork flows with predicted flows under apportionment reveals that the measured 1978 average April flows were only slightly higher at Stations 1 and 3 than the predicted flows under scenario 29 (i.e., 2 units at 1985 water use) (Table 5.6-8). Therefore, with up to two power plant units, the walleye and pike spawning on the East Fork should be approximately equal to the 1978 level of success with a return period of two years. However, in one out of ten years with one or more units in operation, the April East Fork flow would average only 0.0 to 4.3 cfs, resulting in severe adverse effects on game fish reproduction. Based on the observed spawning - flow relation- ships in the East Fork, it is expected that the flow apportionment has a lower potential for adverse impact on fish spawning in the main river and middle forks. However, the apportionment will also affect flows in the main river and long-term effects on strea n morphology may occur. The flow-spawning success relationship presented in Figure 5.6-4 may be used to provide a quantitative estimate of impacts on fish popu- lations due to the power plant operation and apportionment. Based on natural and historical April transboundary flows (scenarios 1 and 2) the mean young-of-the-year class strength for walleye and northern pike is about 235/ni and 77/mi, respectively (Table 5.6-9). 204 ------- 500 + 400 300 200 E 0 U i C-, z a z cZ U i >- Ii 0 0 z 0 Figure 5.6—4 00 I0 0 - 0 100 MEAN APRIL TRANSBOUNDARY FLOW (cfs) RELATIONSHIP BETWEEN FLOW AND YEAR-CLASS FORMATION OF GAME FISH IN THE EAST AND MIDDLE FORKS OF THE POPLAR RIVER KEY: WALLEVE o NORTHERN PIKE — BEST FIT LINE FOR WALLEYE —— BEST FIT LINE FOR PIKE 0 .0 I 000 205 ------- Table 5.6-9 PREDICTED IMPACT OF FLOW APPORTIONMENT ON YOUNG-OF-THE-YEAR CLASS STRENGTH OF POPLAR RIVER GAME FISH Predicted M 0+ Density* Percent Power Ap l (No./Mile) Reduction Scenario Plants Flow (cfs) Walleye N. Pike Walleye N. Pike 1-2, Natural- 0 28.6 235 77 0 0 Hi storical 28 Apportionment, 1 11.4 160 45 32 42 1975 use 29 Apportionment, 2 2 <20 <10 >90 >87 1985 use * 0+ means young-of-the-year class. 206 ------- Operation of one power plant (scenario 28) would result in a 32 percent reduction in the young-of-the—year walleye density during a median flow year. With two power plants and the 1985 level of develop- ment (scenario 29) the predicted impact would be a greater than 90 per- cent reduction in young—of-the-year walleye densities. The corresponding reductions in northern pike densities for scenarios 28 and 29 are 42 percent and greater than 87 percent, respectively. Several important points should be emphasized regarding the flow related impacts on fish: • The predicted impacts are for the lower portions of the East Fork. The impacts on the already marginal fish habitat in the upper East Fork will probably be greater. • The impacts are predicted for median flow conditions under the indicated apportionments. During low flow years (e.g., tenth percentile) the impacts under apportionment would be considerably greater, probably resulting in complete failure of the year class in the East Fork. • The predicted impacts are based on the maintenance of currently existing channel morphology and sub- strate type. Flow related impacts on such physical conditions would compound the overall biological impacts. • Impacts on young-of-the-year gamefish are not neces- sarily manifested directly as changes in the size of adult fish populations. Density dependent mechanisms may act to ameliorate the initial poor year class formation, resulting in less effect on subsequent older age groups. Mitigation of flow related impacts on Poplar River fish populations would require maintenance of specified instream flows by controlled reservoir releases. Two types of flow regimes would be required: • Maintenance of flow required to provide spawning habitat for gamefish during April-May. • Maintenance of peak flows to preserve channel morphology. 207 ------- Based on the fish data collected by Stewart (1980), it appears that a transboundary flow of at least 10 cfs during April and May would insure the successful spawning and rearing of both walleye and northern pike in the mid and lower East Fork. Although some recruitment would occur at average flows between 2 and 10 cfs, the long-term effects of such flow regimes would most likely be a decline in the East Fork gamefish popula- tions. It should be emphasized, however, that the production of young aamefish would increase at flows of 10 to 200 cfs. Therefore, a spawn- ing period flow of 10 cfs should be considered as a minimum for maintain- ing gamefish spawning and rearing at a level that would sustain gamefish recruitment in parts of the East Fork. Based on the flow modeling results, the operation of one power plant with 1975 water use (scenario 28) would result in a median April trans- boundary flow of 11.4 cfs. Under such flow conditions there would be successful gamefish recruitment in the East Fork in average or high flow years, if channel morphology were maintained. However, during low flow years (e.g. , 10 percentile, Table 5.6-8) there would be insufficient flow under the apportionment schedule for successful gamefish spawning. It is durinq such low-flow years that flow augmentation by increased April-May reservoir releases would provide mitigation against adverse impacts on fish populations. The previous analyses in this section indicate that a peak flow of about 715 cfs would be required to provide sufficient scouring of fine material to maintain the present riffle-pool configurations. The required duration of the peak flow is unknown; however, it would most likely be in the range of 2.5 days to 33 days. Since flows of this magnitude have not been historically maintained for a monthly period, the required duration of peak flows is probably nearer the lower limit of the indicated range. In order to provide optimal mitigation, the peak flow release should be provided shortly before the spawning period in April-May. The Biological Resources Committee (BRC) of the International Poplar River Water Quality Board (IPRWQB, IJC, 1979) has provided estimates of water requirements in the East Fork necessary to meet various biological objectives. The objectives for maintenance of gamefish spawning and rearing habitat are 15 cfs in April and 10 cfs in May at the International Boundary. The BRC’s April recommendation is higher than the estimate of 10 cfs contained in this document. The committee’s recorimended require- ment for maintenance of channel integrity is an 18-day release, consisting of at least 123 cfs for 16 days and a peak of 700 cfs for two days within the period. The BRC’s peak flow recommendation is the same as the flow requirements presented in this document; however, no duration of flow was contained herein. Based on our evaluation of the overall range required (2.5 to 33 days), the BRC estimate would be of comparable macnitude. Montana Department of Fish and Game (1979) has recently published recommendations for instream flows to protect walleye and northern pike in the Poplar River. The April and May recommended flows are the same as the BRC’s estimates, i.e., 15.0 and 10.0 cfs, respectively. Table 5.6-10 208 ------- Table 5.6-10 RECOMMENDED INSTREAM FLOWS FOR THE EAST FORK OF THE POPLAR RIVER Month January February March April May June July August September October November December Upper Reach* 2.0 2.0 5.0 15.0 10.0 5.0 3.0 3.0 3.0 3.0 2.0 2.0 3.0 3.0 5.0 15.0 10.0 5.0 4.0 4.0 4.0 4.0 3.0 3.0 * Boundary to Highway 13 bridge tHighway 13 bridge to mouth East Fork Flow (cfs ) Lower Reacht 209 ------- presents the recommended flows for the remainder of the year for both upper and lower reaches of the East Fork. Flow recommendations (Montana Department of Fish and Game, 1979) were based on the previously discussed spawning flow requirements and channel maintenance flows. In addition, flows for the remainder of the year were based on the observations that game fish seem to be maintained at flows less than mean flows. The months of January and February are exceptions in that the recommended flows are higher than mean flows due to the poten- tial for under-ice mortalities at low flows. The overall effects of apportionment on Poplar River game fish will be primarily associated with changes in spawning period flows and channel forming flows. The effects of modified instream flows during the remainder of the year are much more difficult to quantify. Although predicted flows under apportionment are less than recommended instream flows under low flow conditions, the effects on fish are unknown. A beneficial effect of apportionment may exist, however, during January—February of low flow years. Under such conditions, natural (predevelopment) flows may reach very low levels (see Figure 5.2-16). Under the recommended apportionment, flow would be maintained at 1.0 cfs, only slightly less than existing conditions (1975 use and reservoir) which would tend to mitigate against under-ice mortality of ganefish. Therefore, the 1.0 cfs release would tend to mitigate against winter gamefish mortalities although it is lower than the Montana Department of Fish and Game recommendation of 2.0 cfs for the upper East Fork. Actual flows would be higher due to ground water. The evaluation of flow related impacts on fish has been oriented towards walleye and northern pike, the two major game species in the Poplar River. Modifications in flow may effect other species as well; however, impact generalizations are difficult to develop due to the variety of fish species present and the lack of specific life history infornation on non- game species. Some species may be adversely affected by reduced flow, while others may benefit from conditions under flow apportionment. Modified flow regimes can also be expected to influence the corununity composition of benthic macroirivertebrates in the Poplar River. Previous studies have indicated that many of the Epheneroptera and Trichoptera of the Poplar River are dependent upon flowing water habitat. The long—term changes in stream morphometry predicted under apportionment will result in a reduction of stream dependent taxa and an increase in macroinverte- brate fauna adapted to ponds or slow moving streams. The overall effects are difficult to assess due to the complex interrelationships of potentially lowered densities due to the loss of riffle habitat and the potential in- creases due to stimulation of macrophyte production. 210 ------- 6. REFERENCES Accu-Labs Research, Inc. 1978. 11485 West 48th Avenue, Wheat Ridge, Colorado. Letter sent to Terry Thoem, EPA, concerning results of Poplar River ash sample analysis. Agarwala, S.C., N.K. Mehrotra and B.K. Sinha. 1964. Influence of ex- changeable sodium of the growth and mineral composition of plants. Journal of the Indian Soc. of Soil Sci. 12:7-23. Allbaugh, C.A. , and J.V. Manz. 1964. 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U.S. Government Printing Office, Washington, D.C. U.S. Environmental Protection Agency. 1977a. National interim primary drinking water regulations. U.S. Government Printing Office, Washington, D.C. U.S. Environmental Protection Agency. 1977b. National secondary drink- ing water regulations. Federal Register, Vol. 42, No. 62. U.S. Geological Survey. 1968. Mineral and water resources of Montana. U.S. Senate Document No. 98. U.S. Government Printing Office, Washington, D.C. Vaughan, B.E., et al. 1975. Review of potential impact on health and environmental quality from metals entering the environment as a result of coal utilization. Battelle energy progress report, Pacific Northwest Laboratories - Battelle Memorial Institute, Richiand, Washington. Wahhab, A. 1961. Salt tolerance of various varieties of agricultural crops at the germination stage. In: Salinity Problems in Arid Zones: Proceedings of the Teheran Symposium. p. 185-192. tJalker, tI.R., G.V. Skogerboe and R.G. Evans. 1978. Best management practices for salinity control in Grand Valley. EPA-600/2-78-162, July. U.S. Environmental Protection Agency, Ada, Oklahoma. Werkhoven, C.H.E. 1964. Boron in some saline and nonsaline soils in southeastern Saskatchewan. Soil Science Soc. Am. Proc. 28:542-545. Whetstone, R.R., W.O. Robinson and H.G. Byers. 1942. Boron distribution in soils and related data. USDA Technical Bulletin 797. Whitaker, S.H. and E.A. Christiansen. 1972. The Empress Group in southern Saskatchewan, Canadian Journal of Earth Sciences, Vol. 9, No. 4 April, p. 353-360. 224 ------- Whitman, W.R. 1976. Impoundments for waterfowl. Canada Wildlife Services Occas. Paper Mo. 22, 22 pp. Wilhour, R.G., Grady E. Neely, David E. Weber and Louis Grothaus. 1977. Response of selected small grains, native range grasses and alfalfa to sulphur dioxide. Corvallis Environmental Research Laboratory, Corvallis, Oregon. Wilhour, R.G. and D.E. Weber. 1975. Response of small grains and forages to sulfur dioxide: A literature review. Corvallis Environmental Research Laboratory. Corvallis, Oregon. Wilhour, R.G., G.E. Meely, D.E. Weber and L.C. Grothaus. 1979. Response of selected small grains, range grasses and alfalfa to sulfur dioxide. In: Bio-environmental impact of a coal-fired power plant. Fourth interim report, Colstrip, Montana, 1978. EPA-600/3-79-O44. pp. 592-609. Yabroff, I.W. and E.M. Dickson. 1979. Coal resources model: An impact assessment tool, draft final report, SRI International, Menlo Park, California (February, 1979). Zison, S.W., K.F. Haven and W.B. Mills. 1977. Water quality assessment: A screening method for nondesignated 208 areas. EPA-600/9-77-O23. U.S. Environmental Protection Agency. August, 1977. 225 ------- 7. LIST OF PREPARERS Thomas C. Ginn, Ph.D . Dr. Ginn served as project manager and was respon- sible for part of the biological impacts analyses. Dr. Ginn is an aquatic ecologist specializing in the effects of environmental pollutants on the distribution and physiology of freshwater and marine organisms. Karen V. Summers, M.S . Ms. Summers served as co-project manager and con- ducted most of the surface water quantity evaluations, water use analyses and part of the water quality impacts. She is a geohydrologist specializ- ing in modeling studies of ground water and rivers and design of field monitoring programs. Stanley W. Zison, Ph.D . Dr. Zison conducted the analyses of baseline water quality. Dr. Zison is an environmental chemist and statistician specializing in waste treatment management and mathematical modeling of the fate of pollutants. William B. Moreland, M.A . Mr. Moreland was responsible for the air qual- ity modeling and prediction of air quality impacts. He is a meteorolog- ical specialist in diffusion analyses, cliriatological analyses and effects of atmospheric turbulence. Thomas Grieb, M.A . Mr. Grieb conducted terrestrial biological effects analyses for both air quality and water quantity considerations. Mr. Grieb specializes in the impacts of energy-related operations on biologi- cal systems. J. David Dean, M.S . Mr. Dean conducted parts of the water quality impacts analyses, especially as they related to agricultural use of water and determined the impacts of boron and salinity on crops. He is an agricul- tural engineer with considerable experience in the use of stochastic! deterministic models for analyzing water demand by irrigated crops. John W. Ryan, MBA . Mr. Ryan was responsible for partial development of the socioeconomic methodology and impact assessment. He is a specialist in the modeling of complex socioeconomic systems in the public and private sectors. Daniel T. Dick, Ph.D . Dr. Dick also contributed to the socioeconomic methodology. He is an environmental economist with considerable experi- ence in regional impact analysis of energy development. Mary E. Gray, B.A . Ms. Gray collected and described information concern- ing the baseline socioeconomic conditions. She has experience in resource planning, impact assessment and energy development analysis. 226 ------- Susan Mara, M.A . Ms. Mara is a hydrologist and served as a consultant on water-related matters in the socioeconomic analyses. Leslie A. Young, M.S . Ms. Young analyzed the direct socioeconomic impacts. She specializes in economic analyses and the development of interview and survey techniques. 227 ------- |