vvEPA United States Environmental Protection Agency Great Lakes National Program Office 536 South Clark Street Chicago, Illinois 60605 EPA-905/4-79-029-J Volume 10 The IJC Menomonee River Watershed Study Effects of Tributary Inputs On Lake Michigan During High Flows Menomonee River ------- FOREWORD The Environmental Protection Agency was established to coordinate adminis- tration of the major Federal programs designed to protect the quality of our environment. An important part of the Agency's effort involves the search for information about environmental problems, management techniques, and new technologies through which optimum use of the nation's land and water resources can be assured and the threat pollution poses to the welfare of the American people can be minimized. The Great Lakes National Program Office (GLNPO) of the U.S. EPA, was established in Region V, Chicago to provide a specific focus on the water quality concerns of the Great Lakes. GLNPO also provides funding and personnel support to the International Joint Commission activities under the U.S.- Canada Great Lakes Water Quality Agreement. Several land use water quality studies have been funded to support the pollution from Land Use Activities Reference Group (PLUARG) under the Agreement to address specific objectives related to land use pollution to the Great Lakes. This report describes some of the work supported by this Office to carry out PLUARG study objectives. We hope that the information and data contained herein will help planners and managers of pollution control agencies make better decisions for carrying forward their pollution control responsibilities. Madonna F. McGrath Director Great Lakes National Program Office ------- EPA-905/4-79-029-J December 1979 Effects of Tributary Inputs on Lake Michigan During High Flow Volume 10 R. Bannerman J.G. Konrad and D. Becker Wisconsin Department of Natural Resources for U.S. Environmental Protection Agency Chicago, Illinois Grant' Number R005142 Grants Officer Ralph G. Christensen Great Lakes National Program Office This study, funded by a Great Lakes Program grant from the U.S.EPA, was conducted as part of the Task C-Pilot Watershed Program for the International Joint Commission's Reference Group on Pollution from Land Use Activities. GREAT LAKES NATIONAL PROGRAM OFFICE ENVIRONMENTAL PROTECTION AGENCY, REGION V 536 SOUTH CLARK STREET, ROOM 932 CHICAGO, ILLINOIS 60605 U.S. Region 5, Ubr.vy (PL-i2Jj 77 West Jackson GpulsvarcL 12ft f tear Chicago, IL 60604*3590 ------- DISCLAIMER This report has been reviewed by the Great Lakes National Program Office of the U.S. Environmental Protection Agency, Region V, Chicago, and approved for publication. Mention of trade names or commercial products does not constitute endorsement or recommendation for use. ii ------- PREFACE The effects of 1. the combined loadings of the Menomonee, Milwaukee and Kinnickinic Rivers during high flows and 2. wind-induced suspension of sediment on the water quality of the Milwaukee Harbor and its vicinity are investigated. Estimates indicate that a significant portion of the annual loadings of pollutantssuspended solids, total- and soluble-Pfrom the rivers and a sanitary treatment plant are retained in the habor due to deposition. About 70% of the suspended solids discharged from the Menomonee River is retained annually in the inner harbor. The dispersion pattern of pollutants entering the inshore zone is manifested as small islands of turbid water and continuous plume is observed during heavy storm events. The transport and amount of pollutants reaching the inshore zone is modified by harbor current patterns and structures and wind direction. Resuspension and/or shoreline erosion contributes a significant increase in the suspended solids annual loading to the inshore zone. iii ------- CONTENTS Title Page i Disclaimer ±± Preface iii Contents iv Figures v Tables vi 1. Introduction 1 2. Summary and Conclusions 4 3. Recommendations 7 4. Field Activities 8 Water Quality Surveys 8 Sediment Surveys 8 Current Measurements 14 5. Results and Discussion 15 Annual River and Sewage Treatment Plant Loadings 15 Water Quality Survey 16 Current and Dispersion Patterns 36 Annual Lake Loading Estimate 37 Bottom sediments 42 Resuspension 45 References 46 iv ------- FIGURES Number Page 1 Milwaukee Harbor 2 2A Sampling locations on 2/13/1976 10 B Sampling locations on 2/25/1976 10 C Sampling locations on 7/28/1976 10 D Sampling locations on 8/28/1976 10 3A Sampling locations on 9/9/1976 11 B Sampling locations on 6/28 and 6/30/1977 11 C Sampling locations on 7/18/1977 11 4A Sampling locations for baseflow and resuspension survey on 4/8/1976 12 B Sampling locations on 5/11/1977 12 C Sampling locations on 5/19/1977 12 5 Locations of bottom sediment sampling sites on 4/8/76 in the Harbor and on 4/19/76 in Lake Michigan proper 13 6 Visible plumes following 7/18/1977 event 38 v ------- TABLES Number Page 1 Sampling trips 9 2 Annual water (m3 x 107) and pollutant (kg x 101*) loadings to the Milwaukee Harbor 17 3 Water quality data in mg/L for two plume transects on 2/13/1976. 18 4 Water quality data in mg/L for two plume transects on 2/25/1976. 19 5 Metal concentrations in yg/L for two plume transects on 2/25/1976 20 6 Water quality data in mg/L for three plume transects on 7/28/1976 21 7 Metal concentrations in yg/L for three plume transects on 7/28/1976 22 8 Water quality data in mg/L for three plume transects on 8/28/1976 23 9 Metal concentrations in Ug/L for three plume transects on 8/28/1976 24 10 Water quality data in mg/L for two plume transects on 9/9/1976 . 25 11 Water quality data, current velocities and directions at harbor stations during three events 26 12 Water quality in mg/L in plume beyond breakwater during 7/18/1977 27 13 Water quality data in mg/L for three plume transects on 4/8/1976 28 14 Metal concentrations in yg/L for three plume transects on 4/8/1976 29 15 Baseflow measurements of water quality at harbor stations ... 30 16 Averages and ranges of baseflow water quality data in mg/L at three harbor sites 31 vi ------- 17 Water temperatures and current velocities and directions at harbor stations on 5/19/1977 32 18 Water temperatures and current velocities and directions at harbor stations 33 19 Water temperatures and current velocities and directions at harbor stations on 7/28/1977 34 20 Mean annual surface concentrations of pollutants in mg/L in the harbor region . 40 21 Sediment analyses (% of oven-dried weight) for Menomonee River, Milwaukee Harbor and Lake Michigan 43 22 Metal concentrations in mg/kg in sediments of Menomonee River, Milwaukee Harbor and Lake Michigan 44 VII ------- 1. INTRODUCTION The water quality of Lake Michigan in the vicinity of the Milwaukee Harbor is impaired relative to the water further offshore (1,2). One source of pollutants to the Milwaukee Harbor and its vicinity is the combined dis- charge from the Milwaukee, Menomonee and Kinnickinnic Rivers. The overall objective of this study was to determine the effects of the inputs from these three urban river basins on Lake Michigan water quality during high river flows. Since the three rivers discharge to the Milwaukee Harbor, the effect of the Menomonee River inputs on Lake Michigan water quality were not iso- lated from the other two rivers. The study was part of Task D of the Pollution from Land Use Activities Reference Group (PLUARG) objective to diagnose the degree of impairment of Great Lakes water quality. Since the three urban rivers are tributary to the Milwaukee Harbor, the study also provided an opportunity to observe the ef- fects of a large enclosed harbor on the transport of pollutants to Lake Michigan. The specific objectives of the study, as outlined in subactivities 3-1 and 3-3 of Task D, were 1. to determine the effect of pollutant materials discharged from the rivers on water quality in the vicinity of the Harbor during high flows, 2. to determine the extent of dispersion in Lake Michigan of particulate and soluble material contributed by the rivers and 3. to investigate the question of wind-induced resuspension and its relative impor- tance as a pollutant source. While previous studies (3) have documented the degraded water quality in the Milwaukee Harbor and its vicinity in general terms, the present study objectives address the quantification of pollutant loadings and description of the mechanisms controlling the transport and dis- persion of pollutants. To fulfill the specific objectives of the project, the study plan cen- tered on obtaining estimates of water quality throughout the Milwaukee Harbor and its vicinity during periods of high river flow and during wind-induced suspension of sediment. Water quality surveys were conducted on 11 occasions, starting with a snowmelt event on February 13, 1976. Overflights during three of these surveys provided imagery from which water quality values could be extrapolated to non-sampled areas and dispersion patterns of pollutants could be evaluated. Measurements of current velocities and direction in the Milwaukee Harbor were used to evaluate the pollutant transport mechanism. For purposes of analysis, the Lake Michigan-Milwaukee Harbor study area was divided into four regions: The inner harbor, the outer harbor, the in- shore zone and the offshore zone (Fig. 1). The inner harbor was bounded upstream by the point on the rivers where the lake and harbor seiche effects were no longer apparent and downstream by the outermost point of the shipping channel. The outer harbor is delineated by the inner harbor and shoreline on the west and the breakwater on the east. The inshore zone is that portion of ------- MILWAUKEE LAKE MICHIGAN MILWAUKEE Jf i, Jones Island STP X Inner Harbor H Outer Harbor 0 Fig. 1. Milwaukee Harbor. ------- the lake within 5 km of the breakwater or the shoreline. The offshore zone is the lake beyond the inshore zone. The Milwaukee, Menomonee and Kinnickinnic Rivers drain watersheds that contain rural and urban land uses and have a combined area of approximately 2200 km (850 mi ). These rivers have a combined mean annual flow of 14.7 cms (520 cfs) discharging to the inner harbor. Individual mean annual flows are: The Milwaukee - 11.6 cms (410 cfs), the Menomonee - 2.6 cms (90 cfs), and the Kinnickinnic - 0.6 cms (20 cfs). The Jones Island Sewage Treatment Plant (STP), which discharges into the outer harbor, had a mean flow for 1976 of 6.2 cms (219 cfs). For purposes of this analysis the inner harbor was considered to discharge into the outer harbor. The physical characteristics of the inner and outer harbors make each distinct from the other. The inner harbor has depths in the range of 2.1 to 8.8 m (7 to 29 ft), and an approximate surface area and volume of 92 ha (227 acres) and 6.2 x 106 m3 (220 x 106 ft3), respectively. The outer harbor has a wider range of depths (1.2 to 11 m or 4 to 36 ft) and greater surface area and volume [525 ha (1300 acres) and 36.8 x 106 m3 (1300 x 106 ft3), respectively]. The inner harbor includes primarily a shipping channel, docking areas and the channelized downstream reaches of the three rivers. The outer harbor closely resembles a lake with two tributaries (the inner harbor and the STP) and the three points of discharge, i.e., the three major openings along the 8.6 km (5.3 mi) breakwater. The inshore zone, which shares the breakwater as a boundary with the outer harbor, is the recipient of the discharge from the three breakwater openings, and, in turn, interfaces with the offshore zone in a much less controlled manner. The inshore zone depths range from 8..5 to 16.5 m (28 to 54 ft), with greater depths occurring with greater distance from the shore- line and breakwater. The bottom sediments of the outer harbor and the inshore zone have been characterized (2). The dominant sediment type reported for the outer harbor was organic silt, with a thickness of 1.3 to 15 cm (0.5 to 6 in). The in- shore zone bottom was primarily silty clayey sand, with significant areas of gravel, hard bottom, and till. ------- 2. SUMMARY AND CONCLUSIONS The effects of the combined inputs from the Menomonee, Milwaukee and Kinnickinnic Rivers on Lake Michigan water quality were investigated. Estimates of annual river loadings indicated the Menomonee River usually discharged 50% of the annual river loadings reaching the Milwaukee Harbor and the effect of the Menomonee River on Lake Michigan water quality could not be isolated from that of the Milwaukee and Kinnikinnic Rivers. The study focused on the area around the Milwaukee Harbor and the area was divided into four regions: The inner and outer harbors and inshore and offshore zones. The inner harbor was bounded upstream by the point on the river where the lake and harbor seiche effects were no longer apparent and downstream by the outermost point of the shipping channel. The outer harbor was separated from the inshore zone by the breakwater and the inshore zone extended 5 km (3.1 mi into the lake. Water quality surveys were conducted in the study area during periods of high and low flow in the rivers. The parameter list included nutrients, suspended solids and metals. The water quality surveys indicated that the concentration levels of the measured parameters decreased with increasing distance from the confluence of the rivers. Each of the four regions were characterized by a different set of concentrations. Average concentrations of suspended solids in the inner and outer harbors, and inshore and offshore zones were 19, 9, 3 and 1 mg/L, respectively. This phenomenon occurred during baseflow and runoff event flow periods. The large concentration gradient of the parameters from the outer harbor to the inshore zone indicated the effectiveness of the breakwater as a barrier to mixing of the waters in the two zones. This pattern of degrada- tion of water quality points both to the rivers and the Jones Island Sewage Treatment Plant (STP) as sources of pollutants to the harbor and the inshore zone. The STP has a mean annual flow of 6.2 cms ('219 cfs) and contributes a major portion of the total annual pollutant loading to the harbor. The run- off events surveyed had an immediate effect on harbor water quality. However, only the concentrations for suspended solids and total organic-nitrogen were higher than the baseflow values in the inner harbor for most events. The water quality of the inshore zone usually was not degraded during high flow periods. Although more pollutants were available in the harbor for transport to the inshore zone, an insufficient portion of the pollutants were trans- ported during most events to increase concentrations in the inshore zone. Only the February 13 and 25, 1976 snowmelt runoff surveys showed slightly elevated suspended solids concentrations, and the exceptionally large rain event on July 18, 1977 produced elevated suspended solids and chlorides in the inshore zone. The results of the event surveys indicated that the current patterns in the harbor and harbor structures were modifying the transport of pollutants to the inshore zone. ------- Current directions and velocities at the harbor mouth opening (between the inner and outer harbors) and at the central breakwater opening (between the outer harbor and the inshore zone) were measured to characterize the mechanism controlling the transport of pollutants between regions. Measure- ments indicate this transport to be controlled more by the action of the lake and harbor seiches than by the combined flow from the rivers. The seiche has been observed to cause the direction of flow for different strata or for the entire water column to reverse itself during runoff events at the harbor mouth and at the central breakwater opening. This oscillation of flow be- tween regions results in a pulsing of the event-generated pollutants from the more polluted region to the less polluted region across these two bound- aries. The pulsing phenomenon also was verified by the water quality at the central breakwater opening alternating between that of the inshore zone and the harbor. The size of the plug of pollutants is dependent largely on the characteristics of the seiche for any period. This apparent pulsing occurs during times of event and baseflow. An exception to the pulsing, seiche- controlled pattern probably occurs during times of exceptionally large event flows, when a relatively consistent flow of water could be expected to move outward into the inshore zone with short residence time in the harbor. On July 18, 1977, the flow at the surface was not observed to reverse direction for the period of measurement. Although the results of watershed studies have indicated a large portion of the pollutants were discharged to the harbor during high flow periods, the net transport of event and baseflow water to the inshore zone was apparently more dependent on harbor current patterns. The harbor current patterns and structures were able to impose a significant residence time on all pollutants discharged into the harbor be- fore entering the inshore zone. In an attempt to quantify the average annual amounts of pollutants reaching the inshore zone, a mass balance equation was used. Residence times were estimated to be 5 and 6 days for the inner and outer harbors, respectively. The residence times were averages for all conditions and probably decrease significantly for the portions of pollutants discharged to the inner harbor during periods of high flows. The percentage of the total annual loadings to the harbor entering the inshore zone was estimated to be 45% for suspended solids, 61% for total-phosphorus, and 35% for soluble- phosphorus. Although the percentages were only gross estimates, they demonstrated that a significant portion of the annual lo'ading from the river and STP were retained in the harbor. Although the portion of the event pol- lutants retained in the harbor was not known, it was estimated that 70% of the suspended solids discharged from the Menomonee River during events was retained annually in the inner harbor. The amount of suspended solids in the plume for the July 18, 1977 event was estimated to be 5% of the total suspended solids entering the inshore zone each year. The pollutants asso- ciated with the particulate matter obviously were settling out during their residence time in the harbor. Higher concentrations of total-phosphorus, organic-nitrogen and metals in the harbor bottom sediments relative to the river and lake sediments provided further evidence that pollutants were deposited in the harbor. The dispersion pattern of pollutants reaching the inshore zone was mani- fested as small islands of turbid water in the inshore zone or a narrow band of turbid water along the outside of the breakwater. Only during the July 18, ------- 1977, event was a continuous plume observed (4 km directly east into the lake from the breakwater central opening). A plume from the Dreakwater northern opening extended approximately 2.5 km in a northeasterly direction on July 18, 1977. On July 19, the breakwater central opening visible plume had not dispersed but rather had grown slightly larger (to 5 km in east-west extent), and a plume out of the breakwater southern opening extended approx- imately 2.5 km parallel to the shore. Since the surface values of suspended solids were higher than the bottom values, it is assumed that the plume extended down to the thermocline. The dispersion of pollutants in the in- shore zone would be highly variable and dependent upon the direction of the wind. The summer current has a weak tendency to go in a southerly direction and the winter currents have a strong tendency to go in a northerly direction. Resuspension and/or shoreline erosion was responsible for elevating the levels of suspended solids along the shore in the vicinity of the Milwaukee Harbor on April 8, 1976. A significant runoff-event had not occurred for almost 2 weeks. The values for suspended solids were higher than those ob- served in the inshore zone during the July 18, 1977, rain event. Approxi- mately twice as much suspended solids was in the water column of the inshore zone in the vicinity of Milwaukee as a result of this resuspension/erosion event than was in the July 18, 1977 rain event plume. The amount of suspended solids in the inshore zone on April 8, 1976 represented about 12% of the annual suspended soli3s loading to the lake from the harbor. Resuspension and shoreline erosion could cause a significant increase in the suspended solids loading to the inshore zone each year. ------- 3. RECOMMENDATIONS 1. Determination of the effect of the Milwaukee Harbor on pollutant trans- port to Lake Michigan is important in understanding the fate of land use related contaminants. The mass balance calculation for estimating the annual loadings to the inshore zone was limited by the availability of pollutant concentration values in the inner and outer harbors, the inshore zone, and in the Milwaukee River. Pollutant concentrations should be obtained on a sea- sonal basis at the USGS station on the Milwaukee River, at three sites in the inner harbor, at five sites in the outer harbor and at five sites in the in- shore zone near the breakwater. Future mass balance calculations should be limited to seasonal loadings to avoid the potential distortion of averaging residence times for the entire year. Mass balance calculations for indivi- dual events would require more detailed sampling in the harbor before, during and after events. 2. Remote sensing data have been obtained to observe the dispersion pattern of the July 18, 1977 inshore zone plume. Extensive water quality data were collected concurrently in the lake, harbor and Menomonee River. The occur- rence of this event near the end of the project period has not allowed time to evaluate all of the concentration data in conjunction with the remote sensing imagery. This evaluation should be continued to further characterize the dispersion patterns of the plume and possible event related loadings to the inshore zone. Future investigation of plume dispersion patterns should continue to use remote sensing imagery as a tool. 3. Although a large portion of the annual pollutant loading entering the inshore zone was discharged by the rivers, the amount and rates of loading to the inshore zone was regulated for the most part by the current patterns at the breakwater openings. Continuous monitoring of flow direction and velocity, and water quality indicators at the breakwater openings would improve the understanding of the net loading of pollutants to the lake. 4. Estimates of pollutant loading to the Lake Michigan inshore and offshore zones from the Menomonee, Milwaukee and Kinnickinnic River Watersheds should be reduced by some proportion to account for the retention of pollutants in the inner and outer harbors. 5. The inner and outer harbors should be considered areas of impaired water quality as a result of point and nonpoint source pollution. ------- 4. FIELD ACTIVITIES Water Quality Surveys Water quality surveys were conducted from February 13, 1976 to July 18, 1977 during eight runoff events (including two snowmelts), two periods of baseflow and one period of wind-induced resuspension of sediment. All samples were collected from a Wisconsin Department of Natural Resources (WDNR) 6 m (20 ft) Starcraft. On event days, samples were collected as soon as possible after the event flows were detected. The dates, meteorological conditions and the peak Menomonee River flows during the water quality surveys are summarized in Table 1. The locations of the individual sampling sites for each survey are shown in Figs. 2 to 4. Sampling sites for event surveys were chosen along straight line transects from the end of the inner harbor, through the breakwater openings, into the inshore zone. The number of event survey sam- pling sites varied from two to six, depending on visible plume characteristics. The sampling sites for the wind-induced resuspension survey on April 8, 1976, were determined to enable interpretation of concurrent satellite imagery. The samples were collected from the surface and at 7m below the surface in the harbor and at the surface and 10 m below the surface for the inshore area. The samples were collected with a clear PVC Kemmerer bottle and stored under ice in polypropylene bottles. The water samples were analyzed within 24 hr at the Wisconsin State Hygiene Laboratory using established procedures (4,5), The analyses performed for each survey included all or part of the following parameter list: Total- and suspended-solids, total- and soluble-phosphorus, organic-nitrogen, (nitrate + nitrite)-nitrogen, ammonia-nitrogen, chloride, alkalinity, total organic carbon, lead, zinc, cadmium, chromium, nickel and copper. Temperature and dissolved oxygen profiles were measured with a YSI dissolved oxygen meter, and secchi disc depths were recorded. Remote sensing data were obtained during three of the water quality sur- veys. Overflights by NASA coincided with water quality surveys on February 25, 1976 and April 8, 1976. Information from these overflights has been described in a NASA report (6). Sediment Surveys Bottom sediment samples were collected in the harbor on April 8, 1976, and in the lake on April 19, 1976. Samples were collected using a weighted Ponar dredge and stored in widemouth jars. These sampling locations (Fig. 5) were chosen to represent areas of different sediment types and depositional rates. The harbor had not been dredged for 6 'yr prior to the bottom sediment 8 ------- Table 1. Sampling trips Sampling date 2/13/76 2/25/76 4/8/76 7/28/76 4/19/76 8/28/76 9/9/76 5/11/77 5/19/77 6/28/77 6/30/77 7/18/77* Rainfall , Comments cm Snowmelt Snowmelt Baseflow and resuspension; Harbor sediment Rain event 1.07 Sediment outside breakwater Rain event 3.05 Rain event 2.29 Baseflow Baseflow Rain event 2.49 Rain event 3.43 Rain event 4.80 Wind direction NW SW E S-SE SE SW NW NW SE W SE SW Avg . wind velocity, kmph 21 16 14 16 13 21 19 13 13 19 24 19 Peak flow at 70th St. cms time 2.2 17.0 1845 2.2 9.7 0945 0.34 30.0 0305 19.7 0320 0.54 0.54 11.7 0930 33.6 1025 83.4 0500 Sampling times 1430 to 1650 1220 to 1630 1430 to 1830 1530 to 1750 1045 to 1440 1120 to 1625 1430 to 2000 1530 to 1930 1315 to 1900 * Rain event started on 7/17/77; the amount of rainfall on this date was 3.38cm with a peak flow of 88 cms observed at 70th St. at 0155 hr. ------- LAKE MICHIGAN MILWAUKEE LAKE MICHIGAN mile kilometer Fig. 2A. Sampling locations on 2/13/1976. Fig. 2B. Sampling locations on 2/25/1976. MILWAUKEE LAKE MICHIGAN MILWAUKEE LAKE MICHIGAN 3 9 10 11 2 1 12 Fig. 2C. Sampling locations on 7/28/1976. Fig. 2D. Sampling locations on 8/28/1976. 10 ------- LAKE MICHIGAN MILWAUKEE L A K E MICHIGAN MILWAUKEE LAKE MICHIGAN mile kilometer Fig. 3A. Sampling locations on 9/9/1976. Fig, 3B. Sampling locations on 6/28 and 6/30/1977. Fig. 3C. Sampling locations on 7/18/1977. ------- MILWAUKEE LAKE MICHIGAN MILWAUKEE MILWAUKEE LAKE MICHIGAN Fig. 4A. Sampling locations for baseflow and resuspension survey on 4/8/1976. Fig. 4B. Sampling locations on 5/11/1977. Fig. 4C. Sampling locations on 5/19/1977. ------- MILWAUKEE LAKE MICHIGAN M4 LM lilwaukee MILWAUKEE 5 LM Kinnlcklnnic R. 1 1 DEE 0 0 ' 1 ' mi le 1 . kilometer 6 LM Fig. 5. Locations of bottom sediment sampling sites on 4/8/76 in the Harbor and on 4/19/76 in Lake Michigan proper. 13 ------- survey. The sediments were analyzed for particle size, total phosphorus and Kjeldahl nitrogen by the Wisconsin Soil and Plant Analysis Laboratory, for chlorinated hydrocarbons by the Wisconsin Alumni Research Foundation (WARF) Institute, Inc., and for total metals by the Wisconsin State Hygiene Laboratory. Current Measurements The direction and velocity of the currents at the end of the inner har- bor and in the breakwater central opening were measured on May 19, 1977, during a baseflow survey, and on June 28, June 30, and July 18, 1977, during runoff event surveys. Measurements were taken using an ENDECO current meter, which provides current direction and velocity, temperature and depth informa- tion. These measurements were recorded at 1.5 m (5 ft) intervals throughout the water column. The sampling boat, anchored and stabilized as much as pos- sible during the time when readings were taken, was positioned near the middle of the 152 m (500 ft) wide, 9.1 m (30 ft) deep channel which occurred at both stations. 14 ------- 5. RESULTS AND DISCUSSION Annual River and STP Loadings The annual loading of pollutants to the Milwaukee Harbor from the three rivers and Jones Island STP were determined as an integral part of inter- preting the results of the study. The annual loading of pollutants from the Milwaukee and Menomonee Rivers was calculated using a ratio estimator tested by the International Joint Commission staff and PLUARG investigators to be an efficient means of estimating tributary loadings (7). The ratio estimator (Eq. (1)) is a product of flow adjusted instantaneous load times a bias factor which accounts for bias in the form of negative or positive correlations between concentrations and flow. + - mv ln y = y -3- -- ~ - Eq. (1) y * n where y is mean daily load, yx is mean daily flow for the water year, m^ is mean daily flow for days concentrations were determined, m^ is mean daily load for days concentrations were determined, and n is number of days concentrations were determined. The covariance Sxy and variance Sx are estimated by: s n Z x.y . nm m _ 1=1 x x y y xy n - 1 n Eq. (2) £ x. - nm2 x n - 1 where respect x. and y. are the individual measured flows and calculated loadings, .tively, for each day concentrations were determined. 15 ------- The equation produces an estimate of the mean daily load (py). The ratio estimator also develops an estimate of the error in the loading value. The values used for concentrations in the Menomonee River were 1976 data obtained by the Menomonee River Pilot Watershed Study at the 70th Street Station. The con- centration of various pollutants in the Milwaukee River were obtained from 1973, 1974 and 1975 U.S. Geological Survey (USGS) data obtained from the Estabrook Park Station in Milwaukee. Necessary flow data were obtained from USGS water year reports for the above station. The yearly loading values are shown in Table 2 for both rivers. The loading values from the Milwaukee River were generally higher with the values of soluble-P and chloride similar for both rivers. Based on the proportion of flow, the Kinnickinnic River pollutant loadings were considered to be 3% of the total loadings from the other rivers. The percentage of the combined river loadings due to runoff events was not calculated due to insufficient event data on the Milwaukee River. However, the results of the Menomonee River study have indicated about 20% of the suspended solids and about 50% of the other parameters were discharged during events. The annual loading of some pollutants for the Jones Island STP was determined by multiplying the average 1976 flow by the average effluent concentration for 1976 (Table 2). The STP had higher load- ings of total-P and chloride than the combined loadings of the three rivers. The STP was a significant source of pollutants to the harbor area relative to the rivers. The combined loading from the river and STP obviously produced enough of an annual load to affect the water quality of the harbor area. Water Quality Survey The results of the event and baseflow water quality surveys demonstrated a general trend of improving water quality with each successive station from the inner harbor to the inshore zone, (Tables 3-19). An example of this trend was the decrease on August 28, 1976 in total- and suspended-solids, total- and soluble-P concentrations from 285, 18, 0.13 and 0.011 mg/L, res- pectively, at station 7 in the inner harbor to 185, 3, 0.02 and 0.003 mg/L, respectively, at station 1 in the inshore zone (Table 8). Averages of all the water quality data obtained in each zone further demonstrate the consis- tent differences in pollutant concentration between each zone. Part of the observed decreases in pollutant concentration was probably due to simple dilution. The magnitude of the differences, however, in such small distances indicated that water movement between the different zones was restricted. The results pointed out the effectiveness of the breakwater as a barrier to mixing between the water in the outer harbor and inshore zone. The dif- ferences in the levels of pollutants between the zones demonstrated that the water quality in the harbor zones was always impaired relative to the inshore zone. At all times the harbor zone was expected to be relatively degraded since it directly receives discharge from the rivers and STP. The concentra- tions in the harbor zones usually were higher at the surface, while the con- centrations in the inshore zone usually were similar at both the surface and bottom. The exceptions to these trends were the high bottom concentration observed at all stations on February 13, 1976 and higher surface concentration in the inshore zone on July 18, 1977. The trend of higher surface concentra- tions was probably a result of the river and STP discharges staying at the surface when the harbor zones were stratified. 16 ------- Table 2. Annual water (m3 x 107) and pollutant (kg x 104) loadings to the Milwaukee Harbor Solids P Source Water Menomonee River 8 Milwaukee River 36 Three Rivers combined** 45 STP 20 Total 6,200 16,000 23,000 16,000 Suspended Total Soluble 1,500 2.8 1.2 1,430 7.6 5.5 3,000 10.7 6.9 780 12.8 2.9 (N03+N02)- N Cl Pb 13 1,250 0.87 36 1,200 3.5 50 2,520 4.5 3,900 *Menomonee River pollutant values were based on 1976 data, Milwaukee River values were based on 1973, 1974, 1975 data, and the STP values were 1976 data. The water data were averages of long term records. **The Kinnickinnic River loading was considered to be 3% of the total loadings from the other two rivers. ------- Table 3. Water quality data in mg/L for two plume transects on 2/13/1976. See Fig 2A for station locations oo Station No . and depth* 1-Surface Bottom 2-Surface Bottom 3-Surface Bottom 4-Surface Bottom 5-Surface Bottom 6-Surface Bottom Solids Total 584 1086 288 994 274 400 168 458 274 536 290 286 Suspended 15 15 10 17 8 22 4 13 5 166 5 5 Total-P EAST 0.16 0.30 0.08 0.26 0.06 0.16 0.02 0.12 SOUTHEAST 0.77 0.06 0.12 0.06 Total alkalinity 182 238 134 222 130 142 104 154 128 136 130 131 Cl 200 450 58 380 45 96 13 125 50 100 56 52 *Bottom samples were taken 7 to 10 m below surface. ------- Table 4. Water quality data in mg/L for two plume transects on 2/25/1976. See Fig. 2B for station locations vo Station No . and depth* 1-Surface Bottom 2-Surface Bottom 3-Surface Bottom 8-Surface Bottom 7-Surface Bottom 6-Surface Bottom Solids Total 580 585 305 455 275 305 230 300 180 180 170 165 Suspended 18 19 15 13 11 13 10 13 8 9 6 6 Total 0.21 0.21 0.08 0.17 0.07 0.08 0.04 0.08 0.02 0.02 0.01 0.01 P Soluble 0.090 0.089 0.036 0.087 0.027 0.033 0.016 0.033 0.006 0.008 0.005 0.005 Total organic 0.90 0.87 0.38 1.12 1.50 0.32 0.26 0.53 0.54 0.18 0.11 0.50 N (NO 3+ N02 ) EAST 1.76 1.78 0.68 1.44 0.59 0.66 0.48 0.66 0.28 0.28 0.25 0.24 Cl 140 150 50 90 40 50 29 55 11 10 8 8 Temperature, DO °C 12.0 10.8 11.9 11.8 12.0 10.7 12.6 11.0 13.1 12.0 13.0 13.2 2.1 4.0 2.2 1.8 2.0 2.0 1.7 1.9 1.2 1.5 1.2 1.0 EDGE OF PLUME 4-Surface Bottom 9-Surface Bottom 5-Surface Bottom 255 305 280 345 175 170 18 62 11 12 7 9 0.06 0.16 0.07 0.06 0.02 0.02 0.024 0.027 0.027 0.047 0.005 0.005 0.37 0.49 0.34 0.46 0.10 0.15 0.53 0.57 0.55 0.73 0.26 0.25 35 40 45 70 10 8 12.1 11.4 12.2 11.2 13.0 13.2 1.8 1.7 2.0 2.2 1.2 1.0 *Bottom samples were taken at 7 to 10 m below surface. ------- Table 5. Metal concentrations in yg/L for two plume transects on 2/25/1976. See Fig. 2B for station locations Station No. and depth* 1-Surface Bottom 2-Surface Bottom 3-Surface Bottom 8-Surface Bottom 7- Surf ace Bottom 5-Surface Bottom Cd 0.3 0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 EDGE <0.2 <0.2 Cr EAST 5 7 4 <3 <3 <3 <3 <3 <3 OF <3 <3 Pb 27 5 4 <3 <3 <3 <3 <3 <3 PLUME <3 <3 Zn 40 20 30 20 20 <20 20 <20 20 <20 <20 Cu 13 8 14 19 6 7 6 6 6 8 14 *Bottom samples were taken at 7 to 10 m below surface 20 ------- Table 6. Water quality data in mg/L for three plume transects on 7/28/1976. See Fig. 2C for station locations Station No. and depth* 1-Surface Bottom 2-Surface Bottom 3-Surface Bottom 4-Surface Bottom 5-Surface Bottom 17-Surface Bottom 6-Surface Bottom 33-Surface Bottom 34-Surface Bottom 32-Surface Bottom 29-Surface Bottom Solids Total 346 292 312 254 262 184 234 204 210 154 156 190 162 158 216 176 180 166 224 234 216 168 Suspended 6 4 6 5 2 3 0 1 0 0 0 0 0 0 0 1 0 1 0 0 0 0 Total 0.11 0.12 0.12 0.08 0.09 0.07 0.07 0.06 0.03 0.01 0.02 0.02 0.01 0.02 0.04 0.03 0.02 0.01 0.04 0.06 0.04 0.02 P Soluble 0.032 0.052 0.048 0.030 0.038 0.019 0.004 0.005 0.003 0.003 <0.003 0.003 <0.003 <0.003 <0.003 0.005 <0.003 <0.003 <0.003 0.003 0.003 <0.003 N Total organic (N03+N02) EAST 0.55 0.48 0.94 0.38 0.44 0.30 0.56 0.51 0.47 0.20 0.48 0.31 0.20 0.15 SOUTHEAST** 0.41 0.42 0.25 0.22 NORTHEAST** 0.55 0.51 0.52 0.39 0.23 0.21 0.21 0.22 0.22 0.22 0.35 0.30 0.32 0.20 0.17 0.25 0.16 0.21 0.32 0.22 0.20 0.20 0.33 0.33 0.33 0.20 Total alkalinity 138 142 140 120 132 110 112 110 114 112 108 112 110 108 116 106 108 108 112 112 112 108 Cl 50 35 44 32 40 14 30 22 22 8 8 6 9 7 24 10 11 8 29 30 25 13 DO 4.0 3.5 3.5 4.5 5.0 6.5 8.6 7.5 9.3 10.2 __ 10.2 10.5 9.2 9.5 10.2 9.8 9.8 9.4 10.0 10.0 Temperature, °C 26 20 24 17 22 15 20 14 21 11 19 11 20 12 19 10 21 20 21 14 *Bottom samples were taken 7 to 10 m below surface. **Stations 1, 2 and 3 are also included in these transects. See EAST transect for data. ------- Table 7. Metal concentrations in yg/L for three plume transects on 7/28/1976. See Fig. 2C for station locations Station No. and depth* 1-Surface Bottom 2-Surface Bottom 3-Surface Bottom 4-Surface Bottom 5-Surface Bottom 17-Surface Bottom 6-Surface Bottom 33-Surface Bottom 34-Surface Bottom 32-Surface Bottom 29-Surface Bottom Cd <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 0.34 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 Cr Pb EAST 4 8 5 3 4 <3 5 7 <3 <3 <3 <3 <3 <3 SOUTHEAST** <3 <3 <3 <3 NORTHEAST** <3 4 <3 <3 6 5 <3 4 3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 Zn 30 120 20 20 30 40 20 20 20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 Cu 42 15 20 16 16 11 32 14 12 11 5 18 10 12 10 10 18 11 16 9 12 7 *Bottom samples were taken at 7 to 10 m below surface. **Stations 1, 2 and 3 also are included in these transects. See EAST transect for data. 22 ------- Table 8. Water quality data in mg/L for three plume transects on 8/28/1976. See Fig. 2D for station locations Station No. and depth* 8-Surface Bottom 7-Surface Bottom 6- Surface Bottom 5-Surface Bottom 4-Surface Bottom 3-Surface Bottom 2-Surface Bottom 1-Surface Bottom 9-Surface Bottom 10-Surface Bottom 11-Surface Bottom 12-Surface Bottom 13-Sur£ace Bottom 14-Surface Bottom 15-Surface Bottom 16-Surface Bottom Solids Total 310 285 305 300 285 270 240 250 245 205 240 215 210 205 185 195 225 190 205 190 205 190 190 190 210 205 200 210 245 260 195 180 Suspended 41 68 22 21 18 32 8 8 6 6 4 3 3 2 3 4 2 0 2 2 3 2 1 0 2 4 2 14 2 48 1 0 Total 0.26 0.22 0.20 0.20 0.13 0.15 0.09 0.09 0.07 0.03 0.05 0.05 0.03 0.02 0.02 0.02 0.05 0.02 0.03 0.01 0.02 0.02 0.01 0.01 0.02 0.02 0.02 0.02 0.05 0.16 0.04 0.02 P Soluble 0.011 0.008 0.008 0.005 0.011 0.013 0.015 0.012 <0.003 0.003 0.005 0.005 <0.003 0.003 0.003 0.003 0.004 O.003 0.003 <0.003 0.003 <0.003 0.003 0.003 0.003 <0.003 <0.003 <0.003 0.004 0.003 O.003 <0.003 N Total organic (NO EAST-I** 3+N02) 1.8 <0.02 1.8 0.52 1.4 < 1.4 1.1 0.87 0.75 0.63 0.81 0.33 0.69 0.63 0.46 0.27 0.49 0.23 EAST-I I*** 0.66 0.35 0.41 0.47 0.42 0.26 0.57 0.16 EDGE OF PLUME 0.42 0.25 0.29 0.20 0.63 1.1 0.51 0.33 0.02 0.02 0.12 0.18 0.20 0.21 0.22 0.24 0.23 0.23 0.21 0.24 0.16 0.21 0.23 0.25 0.24 0.26 0.23 0.26 0.17 0.24 0.24 0.25 0.23 0.27 0.23 0.25 0.23 0.24 Total alkalinity 84 64 110 118 120 120 116 114 116 110 114 118 112 108 108 108 116 110 112 110 110 110 108 110 110 110 108 110 114 110 114 110 DO 0.2 2.0 0.3 0.2 2.9 4.8 5.1 8.3 7.5 9.0 7.6 7.4 8.5 8.6 8.8 9.0 7.7 9.6 9.0 9.6 9.2 9.8 9.0 9.6 9.4 9.7 9.5 9.8 7.7 8.8 8.8 8.8 Temperature, °C 23 21 26 24 21 17 18 11 18 9 20 19 16 16 19 18 18 8 13 7 13 7 17 7 13 7 12 7 19 10 17 10 *Bottom samples were taken 7 to 10 m below surface. **Samples collected between 1430 and 1615 hrs. ***Samples collected between 1650 and 1725 hrs. 23 ------- Table 9. Metal concentrations in yg/L for three plume transects on 8/28/1976. See Fig. 2D for station locations Station No. and depth* Cd Cr Pb Zn Cu Ni EAST-I** 8-Surface Bottom 7-Surface Bottom 6-Surface Bottom 5-Surface Bottom 4-Surface Bottom 3-Surface Bottom 2-Surface Bottom 1-Surface Bottom 2.5 3.1 2.6 2.0 4.5 2.5 0.7 2.3 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 1.0 <0.2 15 12 13 29 18 36 11 12 3 <3 <3 <3 <3 <3 <3 <3 9 10 11 6 6 25 8 5 <3 <3 <3 <3 <3 <3 <3 <3 100 80 90 40 80 80 60 70 <20 <20 <20 <20 <20 <20 <20 <20 47 32 47 10 40 32 24 28 19 9 9 6 4 5 18 3 4 4 4 5 6 4 4 4 2 2 _ _ _ _ _ - EAST-II*** 9-Surface Bottom 10-Surface Bottom 11-Surface Bottom 12-Surface Bottom 13-Surface Bottom 14-Surface Bottom 15-Surface Bottom 16-Surface Bottom <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 <0.2 2.1 <0.2 <0.2 <3 <3 <3 <3 <3 <3 <3 <3 EDGE <3 <3 <3 <3 3 40 <3 <3 <3 <3 <3 <3 <3 <3 <3 <3 OF PLUME <3 <3 <3 <3 <3 5 <3 <3 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 <20 80 <20 <20 20 6 18 4 8 5 4 10 8 3 8 4 13 33 6 6 2 1 2 3 2 3 2 3 2 2 6 4 3 6 4 3 *Bottom samples were taken 7 to 10 m below surface. **Samples collected between 1,430 and 1,615 hr. ***Samples collected between 1,650 and 1,725 hr. 24 ------- Table 10. Water quality data in mg/L for two plume transects on 9/9/1976. See Fig. 3A for station locations Station No . and depth* 1-Surface Bottom 2-Surface Bottom 3-Surface Bottom 4-Surface Bottom 5-Surface Bottom 6-Surface Bottom Solids Total 280 260 285 200 260 175 205 165 180 175 160 160 Suspended 21 16 68 12 12 8 8 3 4 4 2 4 Total 0.17 0.17 0.16 0.07 0.12 0.07 0.06 0.03 0.03 0.03 0.01 0.02 P Soluble 0.010 0.007 0.008 0.020 0.011 0.008 0.010 0.004 <0.003 <0.003 <0.003 0.020 Total organic 1.11 0.76 1.04 0.46 0.73 0.24 0.42 0.18 0.32 0.25 0.10 0.12 N (NO 3+ N02) EAST 0.28 0.21 0.24 0.24 0.20 0.27 0.41 0.24 0.30 0.26 0.14 0.23 Total Alkalinity 110 126 128 114 126 112 114 108 110 108 106 108 Temperature, DO °C 0.2 2.2 0.9 5.2 3.4 6.2 7.4 7.2 9.1 9.2 9.1 8.8 26 19 23 16 21 15 18 12 18 12 18 17 SOUTHEAST** 12-Surface Bottom 11-Surface Bottom 10-Surface Bottom 9-Surface Bottom 8-Surface Bottom 200 160 225 205 180 180 170 175 170 160 5 3 3 5 6 5 6 6 5 6 0.05 0.03 0.06 0.04 0.03 0.03 0.02 0.02 0.02 0.02 0.004 0.004 0.008 0.004 <0.003 <0.003 <0.003 <0.003 0.004 <0.003 0.39 0.90 0.59 0.36 1.59 0.43 0.24 0.23 0.74 0.18 0.38 0.25 0.39 0.35 0.25 0.29 0.20 0.23 0.21 0.21 112 110 114 112 108 110 106 108 106 108 8.4 7.4 7.6 7.9 8.7 8.8 9.2 9.0 9.2 9.2 18 13 18 18 17 15 17 11 17 17 *Bottom samples were taken 7 to 10 m below surface. **Stations 1, 2 and 3 also are included in this transect. See EAST transect for data. ------- Table 11. Water quality data, current velocities and directions at harbor stations during three events Time, hr 1510 1515 1630 1635 1815 1830 1905 1910 1530 1540 1720 1725 1845 1850 1925 1935 1550 1555 1400 1405 1515 1520 1700 1710 1905 1915 1615 1620 1730 1740 1845 1850 1330 1335 1445 1450 1715 1720 1740 1745 *See Fig. **See Fig. Depth, Suspended m solids, mg/L 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 0 7 3B for 30 for 12 14 10 9 9 6 8 6 STATION 6 4 6 3 4 4 4 2 STATION 3 3 STATION 2 2 35 40 27 34 23 25 STATION 26 22 25 22 25 26 57 41 STATION 25 6 16 2 22 15 station locations. station locations. P^ Total STATION 0.11 0.07 0.12 0.04 0.09 0.05 0.10 0.04 NO. 2* 0.04 0.02 0.05 <0.02 0.04 0.04 0.04 0.02 NO. 3* 0.03 <0.02 NO. 4* <0.02 <0.02 STATION 0.12 0.16 0.12 0.12 0.11 0.08 NO. 2* 0.04 0.02 0.03 0.02 0.04 0.04 STATION 0.20 0.10 NO. 2** 0.12 0.02 0.06 0.02 0.08 0.06 mg/L Soluble Temperature, Cl, mg/L DO, mg/L °C Current Velocity, kmph Direction, degrees NO. 1* - HARBOR MOUTH - 6/28/1977 0.039 <0.004 0.031 0.004 0.017 0.004 0.014 0.004 5.0 8.6 3.8 8.6 4.6 9.4 8.0 12.0 19 12 20 12 19 11 18 12 1.3 0.28 0.74 0.56 0.46 0.46 0.46 0.46 100 350 80 285 65 310 75 265 - BREAKWATER CENTRAL OPENING - 6/28/1977 <0.004 <0.004 0.006 <0.004 <0.004 <0.004 <0.004 <0.004 - 0.8 km EAST <0.004 <0.004 - 1.6 km EAST <0.004 <0.004 10.0 9.8 8.2 9.1 11.2 12.0 9.0 12.0 OF BREAKWATER - 6/28/1977 12.0 12.0 OF BREAKWATER - 6/28/1977 10.8 11.6 16 14 17 8 16 10 16 8 15 12 12 10 0.93 0.56 0.37 0.46 0.93 0.37 0.83 0.28 90 135 140 250 120 140 115 140 NO. 1* - HARBOR MOUTH - 6/30/1977 0.011 0.040 <0.004 0.012 0.009 0.009 - BREAKWATER <0.004 <0.004 <0.004 <0.004 0.004 0.006 8.9 8.8 3.7 5.7 4.8 7.4 CENTRAL OPENING - 6/30/1977 10.5 10.7 10.5 10.4 16 13 18 16 17 13 10 10 10 10 12 12 0.56 0.56 1.20 0.65 0.74 0.30 0.37 1.57 0.74 0.83 0.65 0.46 277 240 90 208 37 218 283 227 158 345 104 172 NO. 1** - HARBOR MOUTH - 7/18/1977 0.041 0.012 - BREAKWATER 0.019 O.004 <0.004 <0.004 0.010 0.050 36 3.0 24 9.4 CEtlTRAL OPENING - 6/30/1977 26 6.3 11 11.0 20 9 21 6.6 20 8.5 24 14 20 10 19 8 20 15 1.11 0.37 0.56 0.83 0.46 0.93 1.11 1.20 90 70 120 290 330 250 95 90 26 ------- Table 12. Water quality in mg/L in plume beyond breakwater during 7/18/1977 event Station* 3. 4. 5. 6. 7. 8. 9. East of Breakwater 5 km East of Breakwater 2.5 km NE of Breakwater 1.5 km East of Breakwater 1 km SE of Breakwater 1.5 km South Exit Breakwater SE of South Breakwater Exit 1.5 km Time, hr 1535 1540 1550 1555 1600 1605 1615 1620 1630 1635 1645 1650 1700 1705 Depth, Secchi m disc, m 0 1.5 10 0 2.0 10 0 10 0 2.0 10 0 1.5 10 0 0.75 7 0 1.0 10 Suspended Solids 6 4 4 4 4 3 6 4 6 4 12 4 6 4 Total 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.02 P Soluble <0.004 <0.004 0.008 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 <0.004 0.008 <0.004 Cl 14 8 11 8 11 8 13 8 12 8 13 8 11 8 DO 18 10 17 9 16 8 15 8 14 9 17 10 14 8 Temperature, °C 10 12 10 12 10 12 10 12 11 12 9 11 10 12 *See Fig. 3C for station locations. ------- Table 13. Water quality data in mg/L for three plume transects on 4/8/1976. See Fig. 4A for station locations Station No . and depth* 1-Surface Bottom 2-Surface Bottom 3-Surface Bottom 4-Surface Bottom 5-Surface Bottom Bottom 7-Surface Bottom 14-Surface Bottom Solids Total 590 408 438 422 446 348 348 288 216 258 174 210 160 164 152 158 Suspended 8 9 6 8 17 12 5 11 8 7 5 30 0 0 1 2 Total 0.18 0.12 0.14 0.12 0.16 0.12 0.10 0.07 0.03 0.05 0.02 0.03 0.01 0.02 0.01 0.01 P Soluble 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. EAST 058 060 058 060 061 036 036 022 Oil 022 0.005 0.005 0. 0. 0. 0. 005 005 003 003 Total organic 0.96 0.83 0.76 0.82 0.77 0.77 0.57 0.54 0.29 0.44 0.24 0.24 0.15 0.21 0.12 0.23 N (N03+ N02) 1.12 0.78 0.85 0.80 0.88 0.59 0.59 0.52 0.38 0.49 0.28 0.29 0.25 0.26 0.24 0.24 Total C :: 10 8 4 4 Cl 90 38 50 42 52 46 48 30 16 25 9 9 8 8 8 8 Temperature, DO °C 7.8 9.0 8.9 8.7 8.4 9.0 9.4 9.4 11.0 10.0 12.4 12.0 12.0 12.0 18 14 14 13 12 10 10 8 7 7 '5 5 3 3 3 3 SOUTHEAST** 11-Surface Bottom 12-Surface Bottom 13-Surface Bottom 322 310 224 288 186 198 4 6 7 7 8 10 0.09 0.09 0.04 0.08 0.03 0.03 0. 0. 0. 0. 0. 0. 039 033 015 029 005 006 0.58 0.57 0.39 0.44 0.23 0.22 0.66 0.61 0.44 0.59 0.31 0.33 41 39 20 33 10 13 9.8 9.5 11.2 10.4 12.0 11.4 9 8 7 7 7 6 NORTHEAST** 3-Surface Bottom 9- Surface Bottom 10-Surface Bottom 15-Surface Bottom 262 260 238 264 182 188 152 152 5 10 15 14 14 19 0 1 0.05 0.07 0.05 0.06 0.03 0.03 0.01 0.01 0. 0. 0. 0. 0. 0. 0. 0. 022 022 016 022 005 005 003 003 0.43 0.37 0.29 0.50 0.21 0.14 0.29 0.11 0.51 0.50 0.43 0.49 0.28 0.28 0.24 0.26 :: :: :: 26 27 20 26 10 8 8 8 10.5 10.0 10.6 9.0 13.0 13.0 7 7 8 8 6 6 3 3 *Bottom samples were taken 7 to 10 m below surface. **Stations 1, 2 and 3 also are included in these transects. See EAST transect for data. 28 ------- Table 14. Metal concentrations* in pg/L for three plume transects on 4/8/1976. See Fig. 4A for station locations Station No. and depth** 1-Surface Bottom 2-Surface Bottom 3-Surface Bottom 4-Surface Bottom 5-Surface Bottom 6-Surface Bottom 7-Surface Bottom 14-Surface Bottom 11-Surface Bottom 12-Surface Bottom 13-Surface Bottom Cr 4 7 8 11 10 8 7 6 <3 4 <3 <3 <3 <3 <3 <3 6 6 3 6 <3 <3 Pb EAST 8 8 5 10 12 6 5 5 4 3 3 5 5 8 <3 <3 SOUTHEAST*** 4 3 <3 4 3 <3 2n 20 30 40 <20 30 20 30 40 30 20 <20 <20 30 20 <20 <20 20 20 <20 20 <20 20 Cu 30 30 22 17 12 12 30 12 44 6 30 20 25 36 3 <3 16 13 11 19 17 8 Fe 1000 600 620 120 960 780 520 640 100 360 280 980 100 100 420 500 360 480 360 400 NORTHEAST*** 8-Surface Bottom 9-Surface Bottom 10-Surface Bottom 15-Surface Bottom <3 5 4 3 <3 <3 <3 <3 3 4 <3 4 <3 7 <3 <3 <20 <20 <20 <20 <20 <20 <20 <20 7 11 11 21 13 30 3 <3 520 520 780 780 840 700 " *Cd levels were <0.2 or 0.2 pg/L. **Bottom samples were taken 7 to 10 m below surface. ***Stations 1,2 and 3 also are included in these transects. See EAST transect for data. 29 ------- Table 15. Baseflow measurements of water quality at harbor stations Time, hr 1045 1335 1115 1440 1225 1355 Depth, 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 0 4 8 Suspended solids, mg/L 6 5 94 6 6 138 8 10 14 82 195 153 15 19 27 96 93 100 P, Total 0.22 0.24 0.38 0.22 0.24 0.51 0.19 0.14 0.14 0.36 0.65 0.54 0.16 0.16 0.14 0.36 0.35 0.37 »g/L Soluble STATION NO. 0.093 0.108 0.092 0.092 0.115 0.092 STATION NO 0.091 0.050 0.045 0.066 0.059 0.057 STATION NO 0.051 0.039 0.024 0.045 0.044 0.042 STATION NO. 6** 1205 1210 1340 1345 1540 1545 0 7 0 7 0 7 4 3 5 4 4 4 0.08 0.02 0.05 0.06 0.06 0.06 0.021 O.004 <0.004 <0.004 0.006 0.008 Current 1* - 13th STREET BRIDGE - 5/11/1977 20 3.5 20 60 2.3 19 90 0.6 16 30 4.2 21 50 2.4 19 730 0.2 17 . 2* - 2nd STREET BRIDGE - 5/11/1977 710 2.5 22 490 4.8 14 420 6.0 12 610 3.2 18 610 3.7 17 580 4.0 16 . 3* - BROADWAY BRIDGE - 5/11/1977 500 5.1 15 510 6.4 12 330 7.2 11 490 5.4 15 450 5.2 14 430 6.0 13 - BREAKWATER CENTRAL OPENING - 5/19/1977 8.0 15 1.75 0.28 90 11.8 10 0.28 255 8.9 15 1.65 0.28 320 8.5 12 0.37 263 9.1 14 1.70 0.28 85 12.4 8 0.37 270 STATION NO. 7** - HARBOR MOUTH - 5/19/1977 1135 1140 1420 1425 1625 1630 1305 1308 1455 1500 0 7 0 7 0 7 0 7 0 7 3 4 3 4 5 4 9 6 14 14 0.12 0.04 0.12 0.07 0.12 0.07 0.16 0.09 0.16 0.17 0.066 0.005 0.063 0.014 0.068 0.011 STATION NO 0.087 0.018 0.068 0.072 STATION NO. 2** 1525 1530 0940 0945 1030 1035 1045 1050 1135 1140 1235 1240 1342 1347 1600 1005 1010 1110 1115 1200 1205 1300 1305 1405 1410 0 10 0 7 0 5 0 7 0 7 0 7 0 7 0 0 7 0 7 0 7 0 7 0 7 2 2 3 78 4 40 4 40 2 112 3 20 56 87 49 2 8 3 13 37 7 3 6 3 233 <0.02 0.02 0.22 0.31 0.20 0.21 0.20 0.21 0.20 0.35 0.20 0.18 0.30 0.36 0.75 0.17 0.12 0.17 0.11 0.16 0.10 0.16 0.12 0.19 0.20 <0.004 <0.004 STATION NO. 0.116 0.049 0.110 0.055 0.110 0.055 0.105 0.034 0.110 0.064 0.073 0.065 0.024 STATION NO. 0.096 0.046 0.088 0.033 0.077 0.032 0.080 0.043 0.105 0.069 5.2 17 0.37 115 10.2 9 0.28 270 5.6 17 1.5 0.18 170 8.9 10 0.18 105 5.2 18 1.5 0.28 130 7.1 11 0.28 95 . 1** - BROADWAY BRIDGE - 5/19/1977 4.6 20 1.5 0.37 150 8.0 10 0.46 340 5.5 19 1.9 0.18 125 6.7 13 0.18 345 - 1.6 km EAST OF BREAKWATER - 5/19/1977 13.1 3.2 12.9 3** - 13th STREET BRIDGE - 5/19/1977 700 1.5 23 500 3.2 15 3.5 18 0.18 285 3.0 15 0.18 310 690 1.8 23 480 690 2.1 23 480 2.9 16 690 2.4 23 490 3.2 16 690 2.4 23 510 2.5 16 5*» - 2nd STREET BRIDGE - 5/19/1977 610 2.4 22 390 6.2 13 610 3.4 23 350 6.7 12 610 3.5 23 330 6.9 12 610 3.4 23 400 7.4 11 530 3.6 20 510 3.9 19 i Fig. 4B for station locatio 30 ------- Table 16. Averages and ranges of baseflow water quality data in mg/L at three harbor sites Solids Total Suspended Spring Average 420 17 Range 350 to 510 6 to 22 Summer Average 300 10 Range 270 to 380 5 to 14 Average 175 2 Range 155 to 180 3 to 18 Average 155 1 P Total Soluble INNER HARBOR* 0.15 0.06 0.13 to 0.18 0.032 to 0.011 0.18 0.04 0.12 to 0.23 0.020 to 0.056 INSHORE ZONE** 0.014 0.004 0.008 to 0.032 0.003 to 0.005 OFFSHORE ZONE** 0.009 0.001 N Total organic (N03+N02) 0.78 0.85 0.71 to 0.95 0.73 to 1.84 0.76 0.20 0.56 to 0.98 0.14 to 0.32 0.21 0.25 0.01 to 0.70 0.10 to 0.29 0.19 0.19 Cl 52 28 to 110 34 25 to 42 12 8 to 16 7 *Baseflow samples obtained at Broadway bridge during 1976. **Based on data from other studies summarized (1) and baseflow survey from this study. ------- Table 17. Water temperatures and current velocities and directions at harbor stations on 5/19/1977. See Fig. 4C for station locations w Samples taken at depth, Time, hr 1300 1305 T 20 0 V D 0.37 160 105 5 T V D 19 0.28 145 105 T 15 10 V STATION 0.18 D NO. I 185 330 STATION NO. 1235 1400 1405 1410 1415 1620 1625 17 17 18 0.37 115 0.18 30 170 290 50 0.18 50 130 17 0.28 105 15 0.18 225 115 75 65 17 0.46 80 80 12 13 16 0.18 0.18 0.46 65 290 70 80 80 80 80 STATION NO. 6 1120 1125 1200 1325 1330 1540 1545 1550 18 15 14 14 " 0.28 70 150 0.28 90 0.28 350 290 0.28 270 85 __ __ 15 0.28 95 14 0.28 240 300 14 0.18 260 75 110 13 12 11 10 0.18 0.28 0.28 0.18 85 150 100 300 270 270 235 100 15 T V BROADWAY 12 0.28 7 HARBOR 9 0.28 11 0.18 13 0.37 m of 20 D T V BRDIGE 310 10 0.46 335 MOUTH 250 9 0.28 235 10 0.18 270 90 100 110 11 0.28 100 D 340 250 265 105 130 95 25 28 TV D TV D ----- 8 0.28 260 _ _ _ _ _ _ _ _ _ - BREAKWATER CENTRAL OPENING -_ 9 0.28 9 0.28 9 0.28 9 0.28 235 9 0.28 270 8 0.37 250 275 7 0.37 285 140 250 255 260 265 275 265 300 _^ ----- 6 0.28 300 7 0.37 240 _ _ 7 0.37 235 260 _ T is temperature in °C, V and D are current velocity in kmph and direction in degrees, respectively. ------- Table 18. Water temperatures and current velocities and directions at harbor stations. See Fig. 3B for station locations Time, hr 1430 1440 1450 1625 1635 1645 1650 1815 1825 1900 1910 1925 1530 1540 1715 1725 1735 1840 1850 1930 1940 1950 2000 1530 1540 1550 1700 1710 1715 1900 1930 1615 1625 1730 1740 1750 1800 1810 1825 1840 T 19 20 20 20 20 19 18 18 18 18 16 16 17 17 17 16 16 16 16 16 16 16 15 18 18 17 17 17 10 10 10 10 12 13 10 11 12 0 V 0.37 1.30 1.39 0.74 0.74 0.46 0.37 0.74 0.56 0.46 0.93 0.93 0.93 0.37 0.93 0.93 0.65 0.83 0.65 0.37 0.37 0.56 1.11 2.26 1.20 0.18 0.74 2.22 0.37 2.26 0.74 0.37 0.37 2.78 1.57 2.96 0.65 D 85 100 65 80 40 65 70 70 65 75 90 45 120 140 155 120 130 115 80 70 45 277 53 74 90 208 37 77 283 232 158 138 271 87 227 278 104 T 20 18 20 18 20 20 17 18 17 18 16 16 16 16 16 16 16 16 16 16 16 16 14 15 18 16 17 16 16 10 10 11 10 12 13 11 11 12 5 V 0.28 0.46 1.20 0.74 0.37 0.65 0.37 0.18 0.37 0.56 0.37 0.74 1.11 0.37 0.37 0.56 0.56 0.93 0.83 0.83 0.37 0.46 0.93 1.11 1.67 0.74 0.56 0.28 2.22 1.39 1.85 0.93 0.18 0.28 1.85 2.22 2.41 0.46 D 75 130 85 70 65 40 160 155 65 45 75 STATION 105 90 100 145 135 90 40 115 40 35 30 270 88 75 97 251 5 83 STATION 248 223 137 138 45 97 255 286 72 Samples 10 T V STATION NO 16 0.18 16 0.28 17 0.46 15 0.28 16 0.56 16 0.56 16 0.93 15 0.65 16 0.65 16 0.18 16 0.18 15 0.28 NO. 2 ] 16 0.56 16 0.56 16 0.46 9 0.1S 9 0.74 16 0.93 16 0.37 16 0.93 16 0.74 16 0.28 14 0.18 STATION NO, 14 0.93 15 1.39 17 1.39 16 0.83 16 0.46 13 0.74 15 0.74 16 2.22 NO. 2. 10 1.20 10 1.67 12 1.20 10 0.37 12 0.65 13 2.22 12 2.59 11 1.85 12 0.65 taken at depth, m of 15 D T V D T 20 V D 25 T V D I 28 V D . 1 HARBOR MOUTH - 6/28/1977 200 14 0.28 165 85 14 0.28 350 335 13 0.28 75 195 14 0.56 235 15 14 0.83 240 215 270 14 0.46 315 210 14 0.28 320 345 14 1.02 220 50 14 0.28 330 330 14 0.18 290 iREAKWATER CENTRAL OPENING 105 16 0.74 135 45 16 0.74 150 85 14 0.28 170 315 8 0.93 345 12 13 12 12 0.28 0.28 0.37 0.56 11 0.46 12 0.37 10 0.56 12 0.93 12 0.46 - 6/28/1977 14 13 10 8 55 16 0.56 150 10 100 15 0.18 120 9 40 12 0.56 150 8 155 12 0.18 120 8 75 10 0.28 165 8 85 8 0.46 185 8 . 1 HARBOR MOUTH - 6/30/1977 285 14 1.11 270 83 14 1.20 74 83 16 1.11 90 57 16 0.93 172 251 14 0.93 228 233 14 0.65 223 218 14 0.56 337 80 15 1.85 80 BREAKWATER CENTRAL OPENING 256 11 1.48 268 226 10 1.85 232 113 12 0.93 75 46 10 0.46 360 337 11 0.74 242 93 13 1-76 82 218 12 0.93 352 286 11 1.67 285 145 12 0.46 80 13 14 16 16 14 0.56 0.74 0.37 0.46 0.37 0.56 0.28 0.28 0.28 0.37 1.30 1.30 0.74 0.28 0.65 14 0.46 14 1.57 - 6/30/1977 11 10 11 10 10 12 12 11 13 1.57 1.57 0.83 0.46 0.83 1.30 1.30 1.76 0.37 315 350 160 285 310 310 250 210 265 135 135 305 250 140 345 140 200 220 190 268 83 85 247 203 320 80 256 227 88 293 320 53 315 285 82 121 0.37 10 0.46 8 0.56 8 0.37 S 0.28 8 0.46 8 0.56 8 0.28 8 0.28 8 0.37 13 0.56 13 0.30 10 0.46 10 0.83 10 0.94 12 1.20 12 1.67 12 0.46 - 120 9 315 - 270 - 300 - 50 - 310 - 345 - 280 - 195 - 190 - 240 - - 218 - 113 - 345 - 14 - 17 - 262 - 172 - 0.28 180 T is temperature in °C, V and D are current velocity in kmph and direction in degrees, repectively. 33 ------- Water temperatures and current velocities and directions at harbor stations on 7/28/1977, locations See Fig. 3C for station Samples taken at depth, m of Time , hr 1315 1325 1350 WOO 1415 T 24 24 24 23 24 0 V 0.93 1.11 0.65 0.93 0.74 D 65 90 75 75 80 T 22 23 23 23 23 5 V 0.83 0.93 0.37 0.83 0.56 D 80 80 95 80 80 T 19 21 21 22 20 10 V STATION 0 83 0.83 0.28 0.56 0.37 STATION NO. 2 1445 1450 1500 1505 1705 1710 1715 1730 1735 1740 1745 1750 1800 1815 1820 1835 1900 20 20 20 20 20 19 19 20 20 20 20 19 19 20 20 16 19 0.56 0.74 0.37 2.78 0 65 0.46 0.46 0.56 0.56 1.11 0.65 0.74 0.28 1.11 1.39 0.46 0.74 120 125 150 345 100 70 330 105 105 95 5 110 330 105 85 250 90 19 19 17 15 20 19 16 18 20 19 19 19 14 20 20 15 19 1.11 0.74 0.46 0.65 0 65 0.46 0.83 0.56 0.65 1.39 0.46 0.65 0.74 0.83 1.20 0.28 0.65 125 135 185 215 105 115 290 1251 110 95 15 110 250 140 95 205 125 14 12 13 14 15 13 14 16 19 17 17 14 18 20 15 19 0.74 0.46 0.74 0.65 0.46 0.65 0.46 0.37 1.48 0.46 0.65 0.74 0.74 1.11 0.46 0.56 D NO. 90 115 80 85 T 1 17 16 18 19 15 V HARBOR 0.56 0.28 0.46 0.28 D MODTH 75 345 75 50 T 14 13 14 15 20 V 0.37 0.46 0.18 0.18 D 70 270 25 265 T 25 V D BREAKWATER CENTRA! OPENING 165 IfiO 240 220 315 240 165 115 90 110 340 250 175 90 225 170 11 12 13 12 13 10 10 14 18 11 13 12 14 20 14 14 0.46 0.37 0.83 0.65 0.74 0.93 0.28 0.28 1.30 0.46 0.37 1.02 0.46 1.20 0.74 0.37 240 220 240 230 240 230 215 125 80 140 325 235 140 80 240 135 10 10 10 10 10 8 10 10 15 11 12 9 12 15 12 11 0.83 0.46 0.83 0.56 0.93 0.93 0.28 0.18 1.20 0.28 0.28 1.02 0.56 1.39 1.02 0.56 290 185 190 240 240 250 235 225 90 225 180 245 75 100 230 175 20 __ 9 10 12 10 12 9 12 12 12 10 0.74 0.37 0.37 1.39 0.56 0.28 0.83 0.65 1.39 0.83 0.37 70 285 330 115 255 180 260 70 105 220 195 T is temperature in °C, V and D are current velocity in kmph and direction in degrees, respectively. 34 ------- Determination of the degree of water quality impairment in the harbor and inshore zones during runoff events was dependent on defining the ranges of pollutant concentrations during baseflow. The mean and ranges of several parameters at the surface for the inshore zone near Milwaukee (Table 16) were obtained from the literature (1). For the purpose of this report the eastern boundary of the inshore zone is 5 km from the break- water. Surface concentration observed during background surveys an May 19, 1977 and April 8, 1976 also were used. Inner harbor surface water quality data collected over a 2-yr period in the Menomonee River Pilot Watershed Project were used to estimate average baseflow pollutant levels for the inner harbor area. The inner harbor trends were assumed to hold true for the outer harbor, since insufficient baseflow data were available. Most base- flow surface water quality values for inshore and harbor zones contained considerable variability; because of this and the fact that different laboratories analyzed the inshore zone samples emphasizes the need for caution in examining the results. In contrast, most of the offshore zone surface concentrations obtained from the literature (1) and this study, showed less variability (Table 16). Baseflow water quality data for the various zones showed that not only were the harbor zones always impaired relative to the inshore and offshore zones but that the inshore zone was always impaired relative to the offshore zone. A comparison of the above baseflow values with event surface water quality in the inner harbor indicates that the water quality of the harbor was usually degraded during runoff events (Tables 3 to 19). During an event the levels of total and suspended solids and total organic N were usually elevated whereas total- and soluble-P levels were seldom increased. In contrast to water quality in the harbor zones, the inshore zone usually was not lowered during an event (Tables 3 to 16). Noticeable exceptions to this trend in the inshore zone occurred on February 25, and September 9, 1976 at two sampling sites (sites 5 and 7 in Figs. 2B and 3A) and July 18, 1977 for suspended solids and chlorides. Although the levels of these parameters were within the range for background values, the values were significantly higher than the means. The event values for these two parameters and the other three parameters were usually close to the mean of the baseflow values for all event surveys in the inshore zone. The two stations with higher values on September 9, 1976 were just outside the south breakwater opening and represented a very small area of contamination in the inshore zone. The higher levels of suspended solids were expected on July 18, 1977 because of the appearance of large areas of turbid water in the inshore zone. The February 25, 1976 values were probably a result of an extended period of high flow during a snowmelt. The trend for the inshore zone obviously indicates that the offshore zone usually was not affected during runoff events. Although water quality in the harbor was affected during runoff events, the inshore zone was rarely altered significantly. Only the July 18, 1977 event with relative high flows [85 cms (3000 cfs) at 70th Street] and rainfall (5 cm) impaired the water quality for a large area of the inshore zone. All the other events were considered more normal with peak flows <42 cms (<1500 cfs) at 70th Street and <2.5 cm rainfall. However, water quality in the inshore zone was definitely degraded relative to the offshore zone. 35 ------- Thus, the data indicate that the input from the harbor was affecting the inshore zone, but this was not noticeable during high flow periods of a commonly occurring event. Transport of event-related pollutants to the inshore zone appears to be controlled by the physical confinement of the harbor and current movement in the harbor. Current and Dispersion Patterns Transport mechanism of pollutants from the inner to outer harbor and through the central breakwater opening to the inshore zone was investigated by observing the direction and velocity of currents during runoff events (Tables 17 to 19). A current direction of approximately 270 degrees indicated that the direction of flow was to the harbor and 90 degrees indicated flow was towards the lake. Currents were observed to reverse direction and stratified flows were recorded for most of the sampling days. The reversal of current direction has been observed as far as 3.2 km above the end of the inner harbor. The current velocity usually varied considerably during a sampling day and represented brief intervals of flow ranging from 62 to 620 cms (2V200 to 22,000 cfs) at the central breakwater opening; and current measurements for events on June 28 and July 18, 1977, indicated that there were periods of stratified flow at each end of the inner harbor and the central breakwater opening. The surface 3 m was observed to have more periods of outward flow than the lower depths. The current direction changed significantly at least once during the brief sampling period for depths below 5m. A reversal of current direction resulted in a change in water temperature. Lake water coming into the harbor significantly lowered the temperature in the upper layers. Pollutant concentrations were higher in the strata flowing towards the lake for both stations on June 28 and July 18 (Tables 18 and 19). Current velocities ranged from 0.28 to 2.8 kmph and usually were higher in the upper 3 mof the water column. The flow was not stratified on June 30, 1977 and the whole water column reversed direction frequently during the period of record (Table 18). Current velocities on this date were generally higher than on other sampling dates. The entire water column at the breakwater opening reflected the temperature of the hypolimnetic water of the inshore zone. Flows were stratified and reversed direction during the period of measurement at both stations for the low flow survey on May 19, 1977 (Table 17); current velocities were consistently low and ranged from 0.18 to 0.37 kmph (0.1 to 0.2 knots). The data from all the sampling days demonstrated the variability in current movement from day to day, however insufficient flow measurements were recorded to predict any long term trends in current direction and velocities. The results of the current measurements suggest that the current pattern in the harbor controls the transport of pollutants to the inshore zone during runoff events. The lake and harbor seiches were probably responsible for the observed current patterns. The pattern of reversing current directions at the central breakwater opening could alternate the discharge ' of harbor water to the inshore zone with lake water coming into the harbor. 36 ------- Pollutants discharged to the harbor during events could have entered the inshore zone in plugs during the event and for some time afterwards with the size and frequency of the plugs probably varying considerably through- out the year. Some portion of the event loading was discharged to the inshore zone after a residence time in the harbor but the relative portion of the event loading that reached the inshore zone during the brief period of high flows was probably small and the amount reaching the inshore zone during most events was insufficient to alter noticeably water quality. An exceptionally large event, such as the one on July 18, 1977, immediately lowered water quality of the inshore zone because a portion of the river water flowed along the surface and reached the inshore zone during the event. The results indicate that the effect of event flows was modified by the harbor current pattern and harbor structures, and the degradation of the inshore zone was probably a more gradual process. The dispersion pattern of the pollutants reaching the inshore zone was difficult to assess in the study, since the only surface plume observed was on July 18, 1977. This plume had dispersed sufficiently in about a day or so as to extend approximately 5 km into the inshore zone from the center breakwater opening (Fig. 6). The plume dispersed symmetrically on either side of an east-west axis. The plumes emerging from the north and south breakwater openings were much smaller in size. The long term dispersion pattern of the plume will not be known until remote sensing data from the two WDNR DC-3 overflights and the LANDSAT satellite have been interpreted. The dispersion of pollutants from the other events surveyed was only visible in the form of small islands of turbid water in the inshore zone or a narrow line of turbid water along the outside edge of the breakwater, however, those conditions existed during baseflow. The dispersion pattern can vary from day to day because of the significant effect of wind on the direction of the surface currents in the inshore zone. Past investigations of the inshore currents in the Milwaukee area indicated that the general flow in spring and summer is highly variable and that small residual flows exist to the south at this time. During the fall and winter, the flow is north past the Milwaukee area with minimum variability. Annual Lake Loading Estimate The results of this study indicate that the transport of pollutants to the inshore zone was modified by harbor currents and structures and therefore the water discharged to the harbor had an undetermined residence time. The pollutant load in the discharge waters was probably reduced by settling processes during residence. Enough of the river inputs have been deposited annually to require dredging to maintain shipping canals. The question remains to determine how much of the annual harbor loadings from events and baseflow ware retained in the harbor zones. Determination of the retention of pollutants from individual events was not attempted from the available data. A mass balance relationship was used to estimate annual inputs to the inshore area from the rivers and the Jones Island STP. The relationship was based on comparing the inputs to the inner or outer harbor for an ------- MILWAUKEE MILWAUKEE Fig. 6. Visible Plumes following 7/18/1977 event. 38 ------- average residence time with the average mass of a pollutant present in those areas. If the amounts of a nonconservative pollutant (e.g., total P) in the inner or outer harbors was exceeded by the inputs for the residence time, part of the nonconservative pollutant was considered to have been retained in these areas. The residence time for the inner and outer harbors was calculated using the concentration gradients of chloride in a residence time equation (Eq.(3)) developed for coastal regions (8). v (css-cL) = - where V = volume in the coastal zone QQ = volumetric flow from rivers and discharges Cgg = mean concentrations in the coastal zone CD = concentration in the river and discharges CL = concentration in the outer lake t = residence time Equation (3) states that the coastal residence time is the mean mass excess divided by the total discharged mass excess. Chloride was used for the calculation of residence times because its mass was assumed to be conserved during transport. The residence time of the harbor areas cal- culated with the chloride concentrations was used in the mass balance equation for determining retention of nonconservative pollutants. The inner harbor was the coastal zone when the outer harbor was considered to be the lake. The concentration values for the terms Cgg ar*d CL used for the inner harbor residence time calculations were averages from available data sources from this study and the Menomonee River Watershed Project (Table 20). Since the inner harbor was not a well-mixed area, the mean concentration of chloride and other parameters were weighted for different areas in the inner harbor. The mean river concentrations of chloride and the other pollutants were obtained by dividing the combined yearly loadings by the combined yearly volume of water discharged (Table 20) . Long term water discharges were obtained from the USGS to determine total water loadings for the river. The residence time of the inner harbor was estimated to be 4.6 days using Eq.(3). The natural residence time of the inner harbor was determined to be 5.2 days; natural residence time being determined by dividing the volume of the harbor by the tributary flow. The estimated residence time represents an average of all possible conditions and probably varies with significant changes in river flows and current movement. The similarity in the natural and estimated residence times probably means a significant increase in discharge to the inner harbor substantially reduces the residence time for a portion of the pollutants. The inner harbor was determined to be flushed 79 times/yr. The outer harbor was the coastal zone when the inshore area was the lake in Eq. (3). The inner harbor was considered to discharge to the outer harbor at a higher rate than the combined river flows. The rate of 1.3 x 10 cms/day was determined by increasing the combined river rates by the ratio of the inner harbor residence time. This rate could be highly 39 ------- Table 20. Mean annual surface concentrations of pollutants in mg/L in the harbor region* Region or tributary Inner Harbor Outer Harbor Inshore Zone Menomonee River Milwaukee River Combined Rivers** Jones Island STP Mean flow, cms 2.5 11.3 14.4 6.2 Solids Total 405 245 180 780 460 510 840 Suspended 19 9 3 190 40 67 40 Total 0.17 0.06 0.02 0.35 0.21 0.24 0.66 P Soluble 0.070 0.016 0.003 0.15 0.15 0.15 0.15 (N03+N02)-N 0.70 0.40 0.22 1.7 1.0 1.1 Cl 54 31 8 160 33 56 200 .p- o *Means include values from this study and the literature. **Combined Menomonee, Milwaukee and Kinnickinnic Rivers. ------- variable and was the best;available estimate for an average rate. Discharges from Jones Island STP were included as inputs to the outer harbor. The values used to solve Eq. (3) were mean values of data obtained from this study and the literature (Table 20) . The mean concentrations for chloride and other parameters in the inshore zone were obtained by combining historical data with results of this study. The residence time calculated for the outer harbor was 5.2 days, which was adjusted to 6 days to allow the chloride inputs and outputs to balance. This adjustment resulted from the need to average chloride concentrations that were highly variable with time and location in the outer harbor. Ideally the residence times should have been calculated for a specific time period like a season for both harbor zones instead of an average residence time throughout the year. Data were not available for such an estimate. The natural residence time of the outer harbor was determined to be 20 days. The higher natural residence time indicates that the current pattern of the breakwater openings increased the transport of water out of the outer harbor. The outer harbor was determined to be flushed 61 times/yr. The percentage of the annual inputs retained in the inner and outer harbors was calculated using the mass balance equation (Eq. (4)). Retained = (QD x CD x t) - (V x Css) QD x CD x t 100 Eq. (4) The terms have the same definitions as in Eq. (3). Equation (4) states that the percentage of material entering the harbor area that is retained depends on the difference between the amount of material input during the residence time and the average amount of material present in the harbor area. The concentration values used for the nonconservative parameters are shown in Table 20. From Eq. (4) the annual river inputs retained in the inner harbor were 70, 22, 52 and 35% for suspended solids, total- and soluble-P and (N03+ N02)-N, respectively; annual inputs from the inner harbor and from Jones Island STP retained in the outer harbor were 1, 33 and 43% for suspended solids and total- and soluble-P, respectively. The 1% value for suspended solids is probably low and represents the sensitivity of the equation to inaccurate estimates of concentrations. The mass balance results from the inner and outer harbors were used to calculate the total amount of all the harbor inputs entering the inshore area/yr. The quantities and percentages of suspended solids, total- and soluble-P discharged annually from the river and STP that enter the inshore area/yr were 17 x 106 (45%), 144 x 103 (61%), and 35 x 103 (35%) kg, respectively. Although the numbers represent gross estimates, the percentages indicate that a significant portion of the pol- lutants entering the harbor area did not reach the inshore area. The most obvious mechanism of retention of the particulate pollutants is deposition during their residence time in the harbor. Soluble pollutants such as 41 ------- soluble-P might be sorbed onto particulate matter or incorporated in the bio- mass in the harbor. The percentage of suspended solids entering the inshore zone/yr was compared to the suspended solids in the inshore plume of July 18, 1977. A concentration of 6 mg/L of suspended solids was assumed over the entire surface area of the plume to the bottom of the thermocline at 10 m. An estimate of 850,000 kg was calculated which was 5% of the annual suspended solids loading to the inshore zone. The amount of suspended solids in the plume was small relative to the total input/yr. The size of the input during one of the only events at which a plume was observed, supports the conclusion that only a small portion of the event loading enters the inshore zone during the brief period of high river flows. Preliminary results from the Menomonee River Watershed Project have shown the annual event loading of suspended solids, total- and soluble-P to be roughly 80, 50 and 50% respectively, of the total annual Menomonee River loadings. Thus, a significant portion of the total annual inputs from these three rivers that were retained in the harbor could have originated from runoff events. Without a great deal of information to verify the adequacy of Eq. (4), it must be assumed that the 70% value calculated is a reasonable estimate of suspended solids retention in the inner harbor. Data from the Menomonee River Watershed would indicate that approximately 80% of the total suspended solids loadings arises during events and without evidence to the contrary it must be assumed that retention in the inner harbor is the same for events and baseflow. Based on these calculations, 8 to 9 x 10 kg of suspended solids was retained in the inner harbor and 3 to 4 x 10 kg entered the outer harbor. Similar calculations could be made with total- and soluble-P with lesser degree of certainty that the estimates are reasonable because of the possible effect of suspended solids concentration on P transformations and most of the P retained in the inner harbor did not arise from annual event loadings. Although the mass balance results indicate that a small amount of suspended solids was retained in the outer harbor, any calculation of event pollutant loading retained in the outer harbor is considered difficult because of the significant contribution from the Jones Island STP. For example, differences in the characteristics of the suspended solids in the sewage effluent and the river make it difficult to assume that the percentage of total inputs are the same for both sources. The above estimates of the amount of the annual event loading retained in the inner harbor are only gross esti- mates. The numbers demonstrate that loading estimates to the lake from land use activities should be significantly reduced. Bottom sediments Bottom sediment survey data indicate that pollutants from the rivers are retained in the harbor area (Tables 21 and 22). Total-P, total-N and metal concentrations were higher in the harbor than in the river and lake sediments. All but one of the sediment samples consisted mostly of sand and silt size fractions. Stations 11H and 12H to the south of the main channel in the outer harbor had lower pollutant values than other harbor stations. A large portion of the pollutants discharged must have been deposited in the main channel and a lesser amount was transported 42 ------- Table 21. Sediment analyses (% of oven-dried weight) for Menomonee River, Milwaukee Harbor and Lake Michigan. See Fig. 5 for station locations Station No. 413008* 413006* 413004* 2H** 3H 4H 8H 11H 12H** 4LM 2LM 5LM 6LM** Sand 46 91 60 54 28 20 16 6 34 39 0 32 60 Silt 46 9 34 40 66 72 76 80 56 56 30 50 32 Clay 8 0 6 6 6 8 8 14 10 5 70 18 8 Total N 0.07 0.03 0.16 0.21 0.25 0.20 0.12 0.13 0.12 0.03 0.03 0.10 0.04 Total P 0.05 0.04 0.06 0.19 0.30 0.34 0.27 0.18 0.08 0.06 0.09 0.09 0.04 * Mainstem monitoring stations on the Menomonee River. **Pesticide concentrations were below detection limits at these. stations. PCB concentrations were 1.6 and 8.3 mg/kg at stations 12H and 6LM, respectively. 43 ------- Table 22. Metal concentrations in mg/kg in sediments of Menomonee River, Milwaukee Harbor and Lake Michigan. See Fig. 5 for station locations Station No. 413008 413062 413004 2H 3H 4H 8H 11H 12H 4LM 2LM 5LM 6LM Cd 1.2 1.4 10 8.4 17 23 18 14 5.8 1.5 2.0 1.0 ' 0.2 Cr 11 32 110 124 1240 1420 880 790 175 15 37 27 6 Pb 83 62 690 440 380 330 250 210 66 30 30 33 7 Zn 180 75 510 370 470 600 570 430 150 42 52 86 21 Cu 18 18 18 63 108 125 104 73 30 8 25 23 5 Fe 30,000 15,000 40,000 40,000 40,000 40,000 40,000 30,000 7,000 19,000 50,000 20,000 Ni 20 20 33 45 43 39 41 21 12 37 36 7 ------- to parts of the outer harbor. Pollutants associated with the particulates discharged during events were probably responsible for the observed enrichment of pollutants in the harbor bottom sediments. Resuspension Aerial photographs obtained by NASA during the overflight on April 8, 1976 confirmed the presence of a narrow band of turbid water along the shoreline extending a number of miles north of the Milwaukee embayment (6). The embayment includes the area between the Linwood Water Purification Plant just north of the outer harbor to Sheridan Park just south of the outer harbor. The turbidity extended further into the lake north of Milwaukee and the suspended material was entering the outer harbor through the north opening. There also was a band of turbidity along the outside edge of the breakwater wall. The suspended material was not discharged into the lake from a runoff event because a significant amount of rainfall had not occurred for almost 2 weeks. Instead, the suspended material may have originated from shoreline erosion and/or resuspension of bottom sedi- ments. Areas of active erosion have been identified just north of the Milwaukee embayment and inshore currents could have transported the sus- pended material to the breakwater. Resuspension was also a possibility, since the inshore area was not stratified. On April 8, 1976 an easterly wind was recorded and the highest turbidity was in relatively shallow (2 to 6 m) water. Concentrations of suspended solids in the areas of turbid water (Station Nos. 10, 6 and 13) were higher than baseflow averages for the inshore zone and areas of low turbidity on April 8, 1976 (Table 13). Some of the concentrations of total-P and total-solids were higher at Stations 10, 6, and 13 than at Station 7 in a low turbidity area. The total-P and total-solids concentration, however, did not usually exceed baseflow averages. The concentration gradients of suspended solids mapped by NASA (6) for April 8, 1976 were used to estimate the amount of suspended solids in the turbid water inside the Milwaukee embayment. Approximately 1.8 x 106 kg of suspended solids were found in the turbid water, which represents about 4.5% of the total annual loading of suspended solids to the harbor or about 12% of the total annual loading leaving the harbor. This amount of suspended solids was about twice as much as suspended olids observed in the July 18, 1977 runoff event plume in the inshore area. The suspended solids concentration was also higher on April 8, 1976 than on July 18, 1977. The annual contribution of suspended solids to the inshore area from a combination of resuspension and shoreline erosion could be significant when compared with the annual input to the inshore area from the Milwaukee harbor. Shoreline erosion or resuspension did not appear to degrade water quality in the inshore zone. 45 ------- REFERENCES 1. Torrey, M. S. Chemistry of Lake Michigan, Vol. 3, Environmental Status of the Lake Michigan Region, Argonne National Laboratory/ES-40, 1976. 418 pp. 2. Ayers, J. C. and J. C. K. Huang. Studies of Milwaukee Harbor and Embayment. In: Studies on the Environment and Eutrophication of Lake Michigan, J. C. Ayers and D. C. Chandler, (eds.). Special Report No. 30, Great Lakes Research Division, University of Michigan, Ann Arbor, Michigan, 1967. 415 pp. 3. Envirex, Inc. Compilation, Analysis and Interpretation of Selected Lake Michigan Water Quality Data. Envirex, Inc., Environmental Science Division, 1974. 286 pp. 4. American Public Health Assoc. R. C. Rand, A. E. Greenberg, and T. J. Taras (eds.). Standard Methods for the Examination of Water and Wastewater, 14th ed. Washington, D. C., 1975. 5. U. S. Environmental Protection Agency. Manual of Methods for Chemical Analysis of Water and Wastes, 2nd ed. EPA 625/6-76-003A, U.S, Environmental Protection Agency, 1976. 317 pp. 6. Raquet, C. A., J. A. Salzman, T. A. Coney, R. V. Svehla, D. F. Shook and R. T. Gedney. Coordinated Aircraft/Ship Surveys for Determining the Impact of River Inputs on Great Lakes WaterRemote Sensing Results. NASA Lewis Research Center, 1977. 7. Bannerman, R., J. G. Konrad, D. Becker and G. V. Simsiman. Surface Water Monitoring Data. Part I: Quality of Runoff from Mixed Land Uses. Final Report of the Menomonee River Pilot Watershed Study, Vol. 3, U.S. Environmental Protection Agency, 1979. 8. Palmer, M. D. Coastal Region Residence Time Estimates from Concentration Gradients. J. Great Lakes Research 1:130-141, 1975. 46 ------- TECHNICAL REPORT DATA (Please read Instructions on the reverse before completing/ 1. REPORT NO. EPA-904/79-029-J 3. RECIPIENT'S ACCESSION NO. 4. TITLE AND SUBTITLE Effects of Tributary Inputs on Lake Michigan During High Flows-Volume 10 5. REPORT DATE December 1979 6. PERFORMING ORGANIZATION CODE 7. AUTHOR(S) R. Bannerman, J. G. Konrad and D. Becker 8. PERFORMING ORGANIZATION REPORT NO. 9. PERFORMING ORGANIZATION NAME AND ADDRESS Wisconsin Department of Natural Resources Post Office Box 7921 Madison, Wisconsin 53707 10. PROGRAM ELEMENT NO. A-42B2A 11. CONTRACT/GRANT NO. R005U2 12. SPONSORING AGENCY NAME AND ADDRESS U.S. Environmental Protection Agency Great Lakes National Program Office 536 South Clark Street, Room 932 13. TYPE OF REPORT AND PERIOD COVERED Final Report 1974-1978 r*p0*o Tl 1 TTio"i ' 14. SPONSORING AGENCY CODE U.S. EPA-GLNP 15. SUPPLEMENTARY NOTES University of Wisconsin-Water Resources Center and Southeastern Wisconsin Regional Planning Commission assisted. 16. ABSTRACT This study was in part of TASK D of the Pollution from Land Use Activities Reference Group (PLUARG) objective to diagnose the degree of impairment of Great Lakes water quality. The overall objective of this study was to determine the effects of input from the Milwaukee, Menomonee and Kinnickinnic Rivers. 17. KEY WORDS AND DOCUMENT ANALYSIS DESCRIPTORS b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group Metal Water Quality Data Sediment Pollutants Organic Total-pho sphorus Soluble phosphorus 18. DISTRIBUTION STATEMENT 19. SECURITY CLASS (ThisReport) Document available to the public through the National Technical Information Service Springfield. VA . 2?.1 61 21. NO. OF PAGES 56 20. SECURITY CLASS (This page) 22. PRICE EPA Form 2220-1 (9-73) D. S. Government Printing Office 1981 750-8 ------- |