U.S. ENVIRONMENTAL PROTECTION AGENCY NATIONAL EUTROPHICATION SURVEY WORKING PAPER SERIES REPORT ON :V\LfE»L LAKE POPE COIMY EPA REGION V UORKING PAPER ilo, 109 PACIFIC NORTHWEST ENVIRONMENTAL RESEARCH LABORATORY An Associate Laboratory of the NATIONAL ENVIRONMENTAL RESEARCH CENTER - CORVALLIS, OREGON and NATIONAL ENVIRONMENTAL RESEARCH CENTER - LAS VEGAS, NEVADA ------- REPORT ON 'VMJEEAL LAKE POPE COUNTY ,'ILflESJTA EPA REGION V PAPER iJo, 1D9 WITH THE COOPERATION OF THE MINNESOTA POLLUTION CONTROL AGENCY AND THE ,'llNNEoOTA NATIONAL GUARD OCTOBER, 1974 ------- CONTENTS Page Fnreword ii List of Minnesota Study Lakes iv, v Lake and Drainage Area Map Vi S e Ct ion s 1. Conclusions II. Lake and Drainage Basin Characteristics 3 III. Lake Water Quality Sumary 4 IV. Nutrient Loadings 9 V. Literature Reviewed 13 VI. Appendices 14 ------- 11 FOREWORD The National Eutrophication Survey was initiated in 1972 in response to an Administration commitment to investigate the nation- wide threat of accelerated eutrophication to fresh water lakes and reservoirs. OBJECTIVES The Survey was designed to develop, in conjunction with state environmental agencies, information on nutrient sources, concentrations, and impact on selected freshwater lakes as a basis for formulating comprehensive and coordinated national, regional , and state management practices relating to point—source discharge reduction and non—point source pollution abatement in lake watersheds. ANALYTIC APPROACH The mathematical and statistical procedures selected for the Survey’s eutrophication analysis are based on related concepts that: a. A generalized representation or model relating sources, concentrations, and impacts can be constructed. b. By applying measurements of relevant parameters associated with lake degradation, the generalized model can be transformed into an operational representation of a lake, its drainage basin, and related nutrients. c. With such a transformation, an assessment of the potential for eutrophication control can be made. LAKE ANALYSIS In this report, the first stage of evaluation of lake and water- shed data collected from the study lake and its drainage basin is documented. The report is formatted to provide state environmental agencies with specific information for basin planning [ 3O3(e)], water quality criteria/standards review [ 3O3(c)], clean lakes [ 3l4(a,b)), and water quality monitoring [ lO6 and §305(b) ] activities mandated by the Federal Water Pollution Control Act Amendments of 1972. ------- 111 Beyond the single lake analysis, broader based correlations between nutrient concentrations (and loading) and trophic condi- tion are being made to advance the rationale and data base for refinement of nutrient water quality criteria for the Nation’s fresh water lakes. Likewise, multivariate evaluations for the relationships between land use, nutrient export, and trophic condition, by lake class or use, are being developed to assist in the formulation of planning guidelines and policies by EPA and to augment plans implementation by the states. ACKNOWLEDGMENT The staff of the National Eutrophication Survey (Office of Research & Development, U. S. Environmental Protection Agency) expresses sincere appreciation to the Minnesota Pollution Control Agency for professional involvement and to the Minnesota National Guard for conducting the tributary sampling phase of the Survey. Grant J. Merritt, Director of the Minnesota Pollution Control Agency, John F. McGuire, Chief, and Joel G. Schilling, Biologist, of the Section of Surface and Groundwater, Division of Water Quality, provided invaluable lake documentation and counsel during the course of the Survey; and the staff of the Section of Municipal Works, Divi- sion of Water Quality, were most helpful in identifying point sources and soliciting municipal participation in the Survey. Major General Chester J. Moeglein, the Adjutant General of Minnesota, and Project Officer Major Adrian Beltrand, who directed the volunteer efforts of the Minnesota National Guardsmen, are also gratefully acknowledged for their assistance to the Survey. ------- iv NATIONAL EUTROPHICATION SURVEY STUDY LAKES STATE OF MINNESOTA LAKE NAME Al bert Lea Andrusia Badger Bart] ett Bear Bemidji Big Big Stone Birch Bi ackduck Bi ackhoof Bu dd Buffalo Cal houn Carl os Carri gan Cass Cl ea iater Co k a to Cr an berry Oar] inq El bow Emb a r as s Fall Forest Green Gui 1 Heron Leech Le I-{omme Dieu Lily Little Lost COUNTY Freeborn Bel trami Po 1 k Koochiching Freeborn Beltrami Stearns Big Stone, MN; Roberts, Grant, SD Cass Be] trami Crow Wing Mart in Wright Hennepi n Do u 91 as Wright Bel trami , Cass Wright, Stearns Wright Crow Wing Dougl as St. Louis St. Louis Lake Washington Kandiyoh i Ca s s Jackson Ca s S Douglas Blue Earth Grant St. Louis ------- V LAKE NAME COUNTY Madison Blue Earth Malmedal Pope Mashkenode St. Louis McQuade St. Louis Minnetonka Hennepin Minnewaska Pope Mud Itasca Nest Kandiyohi Pelican St. Louis Pepin Goodhue, Wabasha, MN; Pierce, Pepin, WI Rabbit Crow Wing Sakatah Le Sueur Shagawa St. Louis Silver McLeod Six Mile St. Louis Spring Washington, Dakota St. Croix Washington, MN; St. Croix, Pierce, WI St. Louis Bay St. Louis, rIN; Douglas, WI Superior Bay St. Louis, MN; Douglas, WI Swan Itasca Trace Todd Trout Itasca Wagonga Kandiyohi Walimark Chisago White Bear Washington Winona Douglas Wolf Beltrami, Hubbard Woodcock Kandiyohi Zumbro Olrnstead, Wabasha ------- v i 9532’ —4542’ c -- ...f . — 45•4) J N .2 ( 1 S Map Location \ — 9530 : : A1 ... . ¶ ,: - ) ) C’ S -> . ) ( MALMEDAL LAKE 0 Tributary Sampling Site X Lake Sampling Site Sewage Treatment Facility IDirect Drainage Area Limits Indirect Drainage Area Mi. Scale ------- MALMEDAL LAKE STORET O. 2752 I. CONCLUSIONS A. Tropnic Condition: It is concluded that flalmedal Lake is eutrophic. Survey limnologists noted the prevalence of rooted aquatic vegetation and extreme turbidity. Uf the 60 Minnesota lakes sampled in the fall iheti essen- tially all were well-mixed, 33 had less rican total pnosphorus and 41 had less mean inorganic nitrogen. For all 80 lakes sampled, 84% had greater transparency, and 75% had less nean chlorophyll a. B. ate-Limiting 1utrient: The algal assay results sho i that Malmedal Lake was phosphorus limited at the time the sample was collected, but the lake data indicate nitrogen limitation in July and Septenber, 1972. C. Nutrient Controllability: Because of the estimations and assumptions nade in the assessment of loadi 1 ig rates, it is not realistic to riake further estimations and assumptions as to loading rata or nutrient controllability, particularly in view of the fact that during the sampi ing year the amount of phosphorus riea- sured leaving the lake was 1.5 times the estimated total load to the lake. ------- 2 It appears there may nave Leen sorie mislabeled samples from the tributaries. The mean total .osphorus in the inlet stream, below the Lowry wastewater pond was about 0.19 mg/i but tile rtiean total phosphorus in t ie outlet of the lake was over 0.25 rng/l (note that the total P concentrati n in the October, 1972, outlet sample was nearly two times the P concentration measured in the lake at about the same time). Now, phosphorus wash-out could have occurred, particularly if point-source contributions had been reduced or eliminated recently; however, as far as is known, no such reduction occurred. A need for a more detailed study of the 1almedal Lake system is indicated. ------- II. LAKE AND DRAINAGE BASIN CHARACTERISTICS A. Lake Morphometry*: 1. Surface area: 195 acres. 2. Mean depth: 6** feet. 3. Maximum depth: 8 feet. 4. Volume: 1,170 acre/feet. 5. Mean hydraulic retention tine: 1.3 years. B. Tributary and Outlet: (See Appendix A for flow data) 1. Tributaries - Name Drainage area [lean flow County Ditch No. 7 4.2 mi2 O.G cfs Minor tributaries & 2 immediate drainage - 3.8 mi 0.6 cfs Totals 8.0 mi2 1.2 cfs 2. Outlet - Unnamed Stream 8.3 mi 1.2 cfs C. Precipitation : 1. Year of sampling: 24.8 inches. 2. ilean annual: 17.9 inches. * DNR lake survey map (1971). ** Anonymous, 1972. t Drainage areas are accurate within ±5%; mean daily flows are accurate within ±10%; and ungaged flows are accurate within ±10 to 25% for drainage areas greater than 10 mi2. tt Includes area of lake. ttt See Working Paper No. 1, "Survey Methods". ------- 4 III. LAKE tIATER QUALITY SUMMARY Flalmedal Lake ias sampled three times during the open-water season of 1972 by means of a pontoon-equipped Huey helicopter. Each time, samples for physical and chemical parameters were collected from two depths at one station on the lake (see map, page vi). During each visit, a single depth-integrated (near bottom to surface) sample was collected for phytoplankton identification and enumeration; and during the last visit, a single five—gallon depth—integrated sample was col— 1 ected for algal assays. Also each time, a depth-integrated sample was collected for cMorophyll a analysis. The maximun depth sampled was 4 feet. The results obtained are presented in full in Appendix 3, and the data for the fall sampl ing period, when the lake was essentially well - mixed, are summarized below. Note, however, the Secchi disc summary is based on all values. For differences in the various parameters at the other sampling times, refer to ppendix B. ------- 5 A. Physical and chemical characteristics: FALL VALUES (10/25/72) Parameter Minimum Ilean Median Maximum Temperature (Cent.) 4.4 4.4 4.4 4.4 Dissolved oxygen (mg/i) 12.4 12.4 12.4 12.4 Conductivity (ijmhos) 600 600 600 600 pH (units) 8.7 8.7 8.7 8.7 Alkalinity (mg/i) 180 180 180 180 Total P (mg/l) 0.060 0.062 0.062 0.065 Dissolved P (mg/l) 0.021 0.023 0.023 0.025 NO + NO (mg/i) 0.100 0.105 0.105 0.110 Am onia mg/1) 0.330 0.330 0.330 0.330 ALL VALUES Secchi disc (inches) 13 15 15 16 ------- 6 1. Pnytoplankton - Sanipling Date 07/06/72 Domi nant Genera 1 . 1icrocystis 2. Oscillatoria 3. Closterium 4. ilelosira 5. Cyclotella Other genera £1 umber per ml 2,651 2,440 2 , 1 99 1 ,566 1 ,084 6,385 1 6 ,325 1 . Melosira 2. ilicrocystis 3. Lyngbya 4. Oscillatoria 5. Flagellates Other genera 1. Oscillatoria 2. Anabaena 3. 1licrocystis 4. Dinobryon 5. Lyngbya Other genera 16,061 11,364 4,848 4,545 4,394 16,212 57,424 1 ,973 1 ,732 1 ,611 422 271 2,093 B. Biological characteristics: Total 09/01/ 72 10/25/72 Total Total 8,102 ------- 7 2. Chlorophyll a — (Because of instrumentation problems during the 1972 sampling, the following values may be in error by plus or minus 20 percent.) Sampling Station Chlorophyll a Date Number (i.ig/fl_______ 07/06/ 72 01 49.8 09/01/72 01 o3.5 10/25/72 01 9.7 C. Limiting Nutrient Study: 1. Autoclaved, filtered, and nutrient spiked - Ortho P Inorganic N flaximum yield pike (mg/l) Conc. (mg/i) Conc. (mg/i) ( mg/i—dry wt.. ) Control 0.014 0.376 7.4 0.005 P 0.019 0.376 8.5 0.010 P 0.024 0.376 9.2 0.020 p 0.034 0.376 9.3 0.050 p 0.064 0.376 9.9 0.050 p ÷ 10.0 N 0.064 10.376 29.8 10.0 N 0.014 10.376 6.2 2. Discussion — The control yield of the assay alga, Selenastrum pri- cornutum , indicates that Ilalmedal Lake had a high level of potential primary productivity at the time the sample ‘ ias collected. Also, the increased yields with increased levels of orthophosphorus (up to about 0.024 mg/i) show that the lake was phosphorus limited. Note that addition of only nitrogen resulted in a yield not significantly different from the control yield. ------- 8 The lake data also indicate phosphorus limitation in October (N/P ratio of 19/1) but nitrogen limitation in July and September (N/P ratios of 4/1 and 10/1 , respectively). ------- 9 IV. NUTRIENT LOADINGS (See Appendix C for data) For the determination of nutrient loadings, the Minnesota National Guard collected monthly near-surface grab samples from each of the tribu- tary sites indicated on the map (page vi), except for the high runoff months of April and May, when two samples were collected, and the colder months of the year when ice cover prevented sampling. Sampling was begun in October, 1972, and was completed in September, 1973. Through an interagency agreement, stream flow estimates for the year of sampling and a “normalized” or average year were provided by the Minne- sota District Office of the U.S. Geological Survey for the tributary sites nearest the lake. In this report, nutrient loads for sampled tributaries were calculated using mean concentrations and the mean monthly flows for the sampling year . Nutrient loadings for unsampled “minor tributaries and irrniediate drain- age” (“ZZ” of U.S.G.S.) were estimated by using the means of the nutrient loads, in ibs/mi 2 /year, in Fish and three unnamed creeks tributary to nearby Big Stone Lake (see Working Paper No. 85) at stations 2709G-l, D-i, E—l, and F-i (19 lbs P and 369 lbs N/m1 2 /yr) and multiplying the means by the Malmedal Lake ZZ area in mi 2 . During the sampling year, the phosphorus load measured in County Ditch No. 7 at station B-i was 380 lbs. This is less than the amount that would have been estimated for the Village of Lowry on a per—capita ------- 10 basis (1970 Census = 257 x 2.5 lbs P/capita/yr = 640 lbs P/yr.) Therefore, in the loading tables that follow, the phosphorus load attributed to Lowry is the load measured at station B-i minus the estimated non-point source load of 19 lbs P/mi 2 /yr (4.2 mi 2 x 19 = 80 ibs). A. Waste Sources: 1 . Known municipal - Pop. Mean Receiving Name Served Treatment Flow (mgd) Water Lowry 257* Pond 0.026** County Ditch #7 2. Known industrial — None * 1970 Census. ** Estimated at 100 gal/capita/day. ------- 11 B. Annual Total Phosphorus Loading - Sampling Year : 1. Inputs — lbs P / % of Source yr total a. Tributaries (non-point load) - County Ditch No. 7 80 16.7 b. Minor tributaries immediate drainage (non-point load) — 70 14.6 c. Known municipal - Lowry 300 62.5 d. Septic tanks - None known e. Known industrial - None f. Direct precipitation* - 30 6.2 Total 480 100.0 2. Outputs — Lake outlet 1 ,200 3. Net annual P loss - 720 pounds * See Working Paper No. 1. ------- 12 C. Annual Total Nitrogen Loading - Sampling Year : 1 . Inputs — lbs NI % of Source yr _____ a. Tributaries (non—point load) — County Ditch No. 7 4,270 51.2 b. Minor tributaries & imediate drainage (non—point load) — 1,400 14.9 c. Known municipal - Lowry 930 11.2 d. Septic tanks - None known e. Known industrial — None — - f. Direct precipitation* - 1,890 22.7 Total 8,490 100.0 2. Outputs — Lake outlet 7,350 3. Net annual N accumulation - 1 ,140 pounds * See Working Paper No. 1. ------- 13 V. LITERATURE REVIEWED Anonymous, 1972. Survey questionnaire. MPCA, Minneapolis. Anonymous, 1973. Wastewater disposal facilities inventory. MPCA, Minneapol is. Schilling, Joel, 1974. Personal comunication (lake map). riPci, f•linneapol is. ------- VII. APPENDICES APPENDIX A TRIBUTARY FLOW DATA ------- IPIMiT6wY FLC)W I.NFO 1MAu10N FO 105r’,OTA 10/30/74 LA F row ‘c ‘AL’IF”AI LAV TOTAL fl2AI’OAGE A4f A OF LA Y ,OPI-4AL I/ F) FL () T IWUTAPY APFA JA) F!r ’ A”H MAY JO JUL AU ), SEP OCT NOV DEC MEAN 2 752 43 4. 31 u.. ‘ 3.”l 0.13 1.66 1.24 1.1 ’ 0.7-, 0.35 0.70 0.27 0.15 0.14 0.62 ?75?CI 0.1w 1.12 3.’.9 2.50 7 I ) 1.53 0.15 1.34 0.56 0.35 0.26 1.24 775271 4 32 0..,’- ‘.‘I J•6Q 1.6? 1.21 1.15 0.17 0.38 0.13 0.28 0.17 0.14 0.62 S J’.14-4 A’. Y TOTAL DOAINA(,E APLA OF LAKE = €‘.29 TOTAL FLOW IN 14.8 ? Stiw OF S JH_1’L)AIrJAr.F APEAS = 8.29 TOTAL FLOW OUT = 34. 143 MEAN MONTrILY FLOWS At) ’) uAILY FLOWS TPI.-)UTAQY IONT- YFA).1 ‘IFI’J FLOW nAY FLOW OAY FL)’W DAY FLOW I I 1? 0.13 IS 0. 80 I i 7 ? (4.44 10 0.60 I , 7? 0.” = 0.0 I 13 O.? 7 0.0 73 O. ’ 4 0.20 3 13 1.2° lu 2.10 4 1 1 1.61 IS 1.60 30 1.20 5 7 ’ 1.36 ?C 0.90 30 I. ’O 6 13 0.4-1 ii 0.70 7 73 0.’3 I i 0.16 73 0.”. 7 0. 14 1 3 (‘.‘ 5 10 0.45 7 75?rI 10 7 ? 1.07 1 2.00 1 1 77 I. ’ ? I C 1.60 I 77 I. ’ 1. 1 40 73 r c c 7 0.60 7 13 0.77 4 0.30 1 73 l— -)3 I ” 4.50 4 f l “.‘6 16 4.10 30 3.10 5 7 ’ 3.wl 20 2.40 30 3.6 ) 74 1. 1 6 II 7 /3 u.” ) I l 0 .40 O 74 C.h4 7 0.47 I. .-’ 30 1.10 I ) , 7 ’ 0.77 1-’ II 7 ’ 0.’.” 3)’ -0.50 I ’ 1 ’ M f l C. ”. 7 0.30 7 0.34- 4 0.20 1 75 1.7 ’ II 1.80 4 13 I. ” ’ IS l.W0 30 1.10 5 7 1.4C 2 1.0) 30 1.1), 6 1 ’ “. ‘ - II 5.7’) 1 1 3 .7 , I l 0.16 7 ,.-“. 7 u.I 73 )) .7 It, 4.67 ------- APPENDIX B PHYSICAL and CHEMICAL DATA ------- STO ET RFTPIEVAL DATE 74/10/30 DATE FROM TO TIME DEPT 1 OF DAY FEET 32217 Cp-lL PHYL A IJG/L 275201 45 40 25.0 095 31 38.0 MAL’IEDAL LAKE 27 MINNESOTA 1 IEPALES 3 72/07/OA 72/09/03 72/ 10/25 16 20 0000 15 10 0000 14 30 0000 49. 8J 63. SJ 9. 7J 2111202 0006 FEET DEPTH 00010 00300 00077 00094 00400 00410 00630 00610 00665 00666 DATE TIME DEPTM WATER DO TRANSP CNDLJCTVY PH 1 ALK N02 NO3 NH3—N PHOS—TOT PHOS—DIS FROM OF TEMP SECCHI FIELD CACO3 N—TOTAL TOTAL TO DAY FEET CENT MG/I INCMES MICROMHO SU MG/L MG/L MG/L MG/L P MG/I P 72/07/06 36 ?0 0000 21.0 11.0 16 520 8.10 188 0.040 0.060 0.147 0.027 16 20 000? 23.0 5.4 520 8.00 193 0.040 0.120 0.209 0.034 72/09/01 15 10 0000 20.0 13 550 8.40 157 0.140 0.220 0.134 0.040 15 10 0004 19.9 11.7 575 8.30 155 0.150 0.280 0.117 0.038 72/10/25 14 30 0000 600 8.70 180 0.110 0.330 0.060 0.021 14 30 0004 4.4 J7 4 600 8.70 180 0.100 0.330 0.065 0.025 J VALUF KNOWN TO 13E IN ERROR ------- APPENDIX C TRIBUTARY and WASTEWATER TREATMENT PLANT DATA ------- ST’)QFT FT- T VA1 •‘Ar. 7 / ) / ‘ LS275 7 1 .5 ‘+1 00.0 0 5 32 00.0 Str 1 i)r NG TO SWAMP NW EDGE OF LK 7.5 LO lRY T/MALMEOAL LAKE C ) HWY 3 XING -WLO LOwRY STP 11r AL S 2)11204 0000 FEET DEPTH OOfR5 0 ’ )0 OOf,71 DATE TIME DEPTH NO?&N03 TOT JEL NH3—N R iOS—DIS riO —TOT FPOM OF N—TOTAL N TOTAL OPTHO TD DAY FEET 1G/L 1r,/L Mf /L P MG/L 7?/10/15 09 53 1.500 1.555 0.071 0.044 0.0b4 72/11/10 11 17 1.370 l.c40 0. OOM 0.040 71/01/10 11 00 3.500 ?.40f, 0.1MG 0.370 3.413 73/04/15 11 05 1.700 7.200 .05f ’ 0.029 0.051 71/04/30 1? 30 .40O ?.510 0.06 0.026 71/05/20 1? 30 .400 p.100 0.024 0.027 0.040 71/05/30 12 30 ?.7 0 0 3.700 0.072 0.027 0.045 11/06/11 11 35 4.303 1.R )0 0.035 0.042 0.055 71/07/17 11 50 p.000 0.051 0.07 7i/o /io 150? .5’J0 4.400 .04? 0.105 1.u5U ------- ST’) ET QE1PTEVAL r).!tTF 7./1u/3 0 ?7 ?C1 LS?752C1 ‘.5 ‘.0 30.0 0Q5 31 00.0 ST’ M ‘)RNG SWAMP AT E END OF LAKE 2? 7.5 LOWRY T/MAL iFDAL LAKE ST rIWY 114 2 M I S OF LOWRY 1IEPALES 2111204 4 0000 FEET DEPTH fl O ’ .10 00 71 00f,f 5 )ATE Tp - ‘) T-I iO? ’O3 TOT PcJEL t1r43—N PrIOS—DIS h’JS-TOT OF J—TflTAL N TOTAL IJPTH() TO DAY F T rM/L ‘1’,L i ( /L iG/L P MG/L 72/10/15 IJQ 45 0.730 .(,50 0.370 0.014 .u15 7?/11/1 L I I’ “.15 ‘.f’O( ( 1.021 0.010 0.135 7 /flh/10 10 0 o.Th) 4.c O O 2.500 O.3 0 0,410 71/04/1 ii 00 O.0’.O 7.1 10 o.32e 0.017 0.140 73/04/30 1? ‘0 3.0 2 5 7.500 0.300 0.030 0.150 71/0S/2 ) 1? 20 Q ,fl27 3.400 t).736 0.0?R 0.13) r /0c/3o 12 70 0.030 ?. 00 0.35( 0.030 0.137 71/0 /1L I’ 10 0.03’ 1.700 0.350 0.0S 0.145 71/07/17 11 445 7. 530 3.3)5 0.200 0.f 0 73/0 /07 11 40 C.01u 1 .f O” 1. 0 fl.?10 0.530 71/0 /10 14 5 3. - 10 3. 115 0.043 0.230 K VALUE KNOWN TO dE LESS T9AN I(’JDICATFD ------- |