Gr-2-77 Limnological Reconnaissance of Seminoe Reservoir, Wyoming
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GR-2-77 LIMNOLOGICAL RECONNAISSANCE OF SEMINOE RESERVOIR, WYOMING by J.F. LaBounty J.J. Sartoris R.A. Roline Applied Sciences Branch Division of General Research Engineering and Research Center Denver, Colorado SI METRIC December 1976 UNITED STATES DEPARTMENT OF THE INTERIOR * BUREAU OF RECLAMATION ACKNOWLEDGMENTS The Lower Missouri Region of the Bureau of Reclamation provided the funding and support for this project. Research was performed under the supervision of N. E. Otto, Head, Environmental Sciences Section, and L. 0. Timblin, Jr., Chief, Applied Sciences Branch. This report is based on a study requested by the Bureau of Reclamation's Lower Missouri Region as part of their Seminoe Dam Modification Studies. The Physical Sciences and Chemical Engineering Section performed the chemical analyses under the supervision of T. E. Backstrom. Final edit- ing and preparation of the manuscript for publication was performed by W. F. Arris of the Technical Services and Publications Branch. The information in this report regard- ing commercial products or firms may not be used for advertising or promo- tional purposes, and is not to be con- strued as an endorsement of any product or firm by the Bureau of Reclamation. CONTENTS Page Abbreviations ...... vi Introduction ....... 1 Application ....... 5 Summary ....... 6 Recommendations ....... 8 Methods and materials ....... 9 Physical-chemical factors ...... 12 Chlorophyll analysis for productivity ...... 12 Benthic analysis ...... 13 Zooplankton ...... 13 Results ...... 14 Physical-chemical factors ...... 14 Water chemistry ...... 21 Heavy metals ...... 26 P-N nutrients ...... 26 Light penetration and chlorophyll concentrations ...... 28 Benthic fauna ...... 33 1 I CONTENTS - Continued I Page I Zooplankton 38 I Bibliography 43 I I I I I I I 1 I I I 1 11 I TABLES Table Page 1 Chemical analyses of water collected from Seminoe Reservoir and its inflows ................ 22 2 Secchi disk readings, light extinction coeffic- ients, and Zed (1 percent light euphotic depths) .......................................... 29 3 Comparison of light extinction coefficients ........ 30 4 Chlorophyll a concentrations ....................... 31 5 Results of benthic studies ......................... 35 6 Comparison, in order of abundance, of benthic fauna, excluding mollusks ........................ 36 7 Concentration of zooplankton ....................... 39 8 Relationship between cladoceran and copepod abundance ........................................ 40 :iii FIGURES Figure Page 1 Area-capacity data, Seminoe Reservoir ....... 3 2 Map of Seminoe Reservoir, Wyoming, with 1976 sampling stations ...... 10 3 Seminoe Reservoir, Wyoming a. In the Red Hills area, facing southeast ...... 11 b. In the Medicine Bow arm area, facing north ...... 11 4 Temperature and dissolved oxygen, profiles ...... 15 5 Conductivity and hydrogen-ion concentration (pH) profiles ...... 16 6 Oxidation-reduction potential, profiles ...... 17 7 Histogram of data on TDS (total dissolved solids), Ca (calcium), and SO4 (sulfate) concentrations at the sampling stations ...... 23 8 Profiles of calcium, magnesium, and sodium concentrations ...... 24 9 Profiles of bicarbonate, sulfate, and chloride concentrations ...... 25 10 Profiles of iron, manganese, and zinc concentrations ...... 27 iv I I FIGURES - Continued I Page I 11 Profiles of chlorophyll a concentrations ........... 32 I 12 Histogram of abundance and biomass of the I benthic fauna .................................... 37 13 Relative abundance of zooplankton .................. 42 I I I I I I I I I 1 I I v ABBREVIATIONS Eh oxidation reduction (redox) potential ha hectare rn metre mg/individual (unit weight) milligram per individual mg/litre (concentration) milligram per litre mg/m2 (wet and dry weight) milligram per square metre mg/m3 (concentration) milligram per cubic metre mm millimetre mV millivolt n/litre (concentration) number per litre (x 1000 = n/m 3) n/m (light extinc- tion coeff.) number per metre n/m2 (abundance) number per square metre n/m 3 (concentration) number per litre 1000 = n/litre) pH hydrogen-ion concentration percent TDS total dissolved solids pmho/cm (conductivity) micromho per centimetre pS/cm (conductivity) microsiemen per centimetre (pmho/cm = pS/cm) Z euphotic depth (1 % light level) ed vi ABBREVIATIONS - Continued -2 co 3 carbonate HCO3-1 bicarbonate ortho-phosphate NH 3-N ammonia nitrogen NO3-N nitrate-nitrogen vii INTRODUCTION Seminoe Reservoir is a mainstream North Platte River reservoir located in Carbon County (south central) Wyoming. It was formed by Seminoe Dam which was built in 1939 by the Bureau of Reclamation and is the uppermost of six major storage facilities on the North Platte River. Figure 1 shows area-capacity data for Seminoe Reservoir. The reser- voir has a capacity of 1 246 800 000 m3 (1 011 000 acre-ft), at water surface elevation 1938 m (6357 ft). The average annual volume is between 555 000 000 and 617 000 000 m3 (450 000 and 500 000 acre- ft), with a surface of about 4050 ha (10 000 acres). Seminoe is one of the major fisheries of Wyoming (Wesche and Skinner [311 1), and accounts for 1.4 percent of the total annual fishing for the state. Game fishes in Seminoe include, in order of abundance [31]: walleye (Stizostedion vitreum vitreum Mitchell), brown trout (Salmi trutta Linnaeus), rainbow trout (Salm° gairdneri Richardson), and brook trout (Salvelinus fOntinalis Mitchell). 1 Numbers in brackets refer to literature cited in the bibliography. (hec AREA CAPACITY CAPACITY CUBIC I ACRES METRES ACRE FEET acres xI03 acre-ft 1 0 0 0 19 e 0 0 0 1 5 4 19 44 328 266 84 658 533 19 : 123 1 309 1,06! 19 : 130 1 388 1,125 254 3 634 2,946 19 472 8113 6,577 664 I 5 1 20 12,258 1 ) 1,009 25 441 20,625 19 1,445 39 066 31 ,671 1,494 40 878 33,140 19 ELEVATION— metres - 2,199 63 1 60 51,204 2,848 93 794 76,039 19 : 3,833 I 34 999 109,444 18 E 4,953 1 89 188 153,375 6,133 257 563 208,807 18 7,513 341 728 277,039 8,519 410 944 333,153 18 8,951 443 268 359,358 18 10,714 564 551 457,682 12,808 709 625 575,294 3 (acre-ft X10 15,265 882 768 715,661 18,150 I 088 856 882,737 6 3 20,291 I 254 835 1 017,297 ( m x10 1 21,233 I 331 643 1,079,565 261 1,189,511 UNITED STATES * 22,745 I 467 DEPARTMENT OF THE I NTERIOR Star LM REGION 24,259 I 1,307,020 &UREIC/ OF RECLAMATION atim 612 209 KENDRICK PROJECT - WYO. NOTE- The 24,941 I 672 897 1,356,220 AREA CAPACITY DATA Floo 26,275 I 767 065 1,432,562 SEMINOE RESERVOIR com INCLUDING SI METRIC 27,563 I 932 095 1,566,352 EQUIVALENTS (ORIGINAL DATA elevo FROM DWG. NO. 144 -700-103) 1 are I phote orfrivER,COLO 77 144 - 700 -10 to co, Figure 1. - Area-capacity data, Seminoe Reservoir. Nongame species include: white sucker (Catostomus commersoni Lacepede), longnose sucker (Catostomus catostomus Forster), carp (Cyprinus carpio Linnaeus), creek chub (Semotilus atromaculatus Mitchell), fathead minnow (Pimephales promelas Rafinesque), northern plains minnow (Hybognathus placitus Girard), bigmouth shiner (Notropis dorsalis Agassiz), longnose dace (Rhinichthys cataractae Valenciennes), and Iowa darter (Ftheostoma exile Girard). APPLICATION This report will be used by the Bureau's Lower Missouri Region planners who requested this reconnaissance as a part of their Seminoe Dam modi- fication study. This baseline information will also be critical to the environmental impact assessment of the North Platte hydroelectric study, and any future projects in the North Platte River basin. In addition, these data will be helpful in the development and management of the fishery of Seminoe Reservoir, and will be of interest to anyone involved in limnological studies. This study is also an example of a baseline limnological survey that could be easily adapted to reservoirs throughout the Bureau's area of operation. 5 1 SUMMARY Data collected during this study will be used to assess the environ- mental impacts of proposed modifications of Seminoe Reservoir. The 1 reservoir becomes only weakly stratified at any station and is influ- enced very heavily by the North Platte and Medicine Bow Rivers. Based on observed data of residents in the area, data collected by Wesche 1 and Skinner [31], and some fragmentary records from USGS (U.S. Geo- logical Survey), reservoir turnover occurs twice a year, during April or May and again during October or November. Wind action probably has a great influence on conditions within the reservoir. An anaerobic con- dition probably is approached, but never quite reached within the water 1 column at any one location. This is due to (1) the lack of strong stratification for any period of time, (2) ambient air temperature, (3) strong winds, and (4) influence of the North Platte and Medicine Bow Rivers. These four factors are all interrelated. According to Pennak [21], Seminoe Reservoir is a nonalkaline body of water2. Values of pH are probably always above 7.0 and generally during the summer they are above 8.0. Calcium is the major cation and bicarbonate and sulfate are the major anions. Station 3 (Medicine Bow Arm) contains the highest concentration of major cations and anions, 2 Pennak [21] considers nonalkali lakes in the Rocky Mountain area as those having total residues of less than 500 mg/litre, and alkali lakes as those having residues in excess of this figure. 6 indicating the Medicine Bow River as being the probable major contrib- utor. This conclusion is further substantiated by data presented from a water sample collected from the Medicine Bow River. There is indi- cation of the presence of some heavy metals (copper, manganese, iron, and zinc), especially at lower depths. However, they probably are not biologically important since redox potentials, D.O. (dissolved oxygen), and pH values were too high for metals to be available in a dissolved form.