Environmental Indicators and Impact Assessment Commons^™

Historical Patterns Of Phytoplankton Productivity In Lake Mead, Richard T. Prentki, Larry J. Paulson

Publications (WR)

Lake Mead was impounded in 1935 by the construction of Hoover Dam. The Colorado River was unregulated prior to then and therefore was subjected to extreme variations in flows and suspended sediment loads. Hoover Dam stabilized flows and reduced suspended sediment loads downstream, but Lake Mead still received silt-laden inflows from the upper Colorado River Basin. The Colorado River contributed 97% of the suspended sediment inputs to Lake Mead, and up to 140 x 1O⁶ metric tons (t) entered the reservoir in years of high runoff. Most of the sediments were deposited in the river channel and formed an …

The Influence Of Lake Powell On The Suspended Sediment-Phosphorus Dynamics Of The Colorado River Inflow To Lake Mead, T. D. Evans, Larry J. Paulson

Publications (WR)

The Colorado River has been successively modified by the construction of several reservoirs, beginning in 1935 with the formation of Lake Mead by Hoover Dam. These reservoirs are located in a chain, and each one has an influence on the nutrient dynamics and productivity of the river and downstream reservoir. Lake Mead derives 98% of its annual inflow from the Colorado River. Historically, the Colorado River inflow was unregulated into Lake Mead. Regulation occurred in 1963, when Lake Powell was impounded by the construction of Glen Canyon Dam, approximately 450 km upstream. The formation of Lake Powell drastically altered the …

Effects Of Wastewater Discharges On Periphyton Growth In Lake Mead, Nevada-Arizona, Marsha Korb Morris

Publications (WR)

A study of the effects of secondary-treated wastewater on periphyton growth in Lake Mead, Nevada-Arizona was conducted from September 1979 to December 1980. Periphyton ash-free dry weight, chlorophyll-a, dominant species composition, and alkaline phosphatase activity were measured on fiberglass substrates. Substrates were incubated for two to four weeks in littoral and limnetic habitats. Physical and chemical variables and phytoplankton chlorophyll-a were measured concurrently.

Transparency increased with increasing distance from the discharge. Secchi depth ranged from 0.75 m at the discharge confluence (station 2) in August, to greater than 20 m at the most distant stations (stations 9 and 10) in …

An Ecological Analysis Of Relic Diatoms In Sediments Of Las Vegas Bay, Lake Mead, David Ross Hetzel

Publications (WR)

Relic diatoms in sediments of the inner Las Vegas Bay, near the Las Vegas Wash sewage inflow, were examined in order to assess historic trophic conditions in this area of Lake Mead. Diatom sedimentation rates and ratios of Araphidineae/Centrales (A/C) diatom groups were determined from sediment cores collected in the old wash channel 1.5 km from the sewage inflow (station 2), in a small cove 1.5 km further downstream (station 3) and in an adjacent embayment off Gypsum Wash (station 4). Diatom sedimentation rates generally increased from the bottom to the top of each core, but pronounced minima existed at …

Development, Verification And Use Of Methods To Model Chemical And Thermal Processes For Lakes Mead And Powell, John Eric Edinger, Edward M. Buchak, Joseph S. Norton, Bureau Of Reclamation

Publications (WR)

Analysis and development of carbonate-bicarbonate chemical subroutine.

Report No 49 - Geographically Restricted Plants Of Southern Western Australia, Barbara L. Rye

Fisheries Research Reports

This publication lists 527 angiosperm species native to southern western Australia whose known geographical ranges are less than 100 kilometres long. A further 128 angiosperms are listed with geographical ranges between 100 and 160 kilometres. No fern or gymnosperm species in the region are known to be geographically restricted.

Apart from the presently unnamed species, a large majority of the rare plants of southern Western Australia are believed to be listed, including 86 of the species that have been gazetted as rare flora.

Less than 40% of the listed species are known to occur on conservation reserves and less than …

The Voluntary Water Quality Monitoring Program : 1982 Project Report, Barbara Welch, Judy Potvin, Mary Ellen Dennis

Maine Collection

The Voluntary Water Quality Monitoring Program : 1982 Project Report

by Barbara Welch, Judy Potvin & Mary Ellen Dennis

Division of Environmental Evaluation and Lake Studies, Maine Department of Environmental Protection, Augusta, Maine 1982.

Contents: Understanding Maine's Lakes and Ponds / Acknowledgement / Temperature / Dissolved Oxygen / Other Measures of Lake Water Quality / Nutrients / Algae and Chlorophyll a / Transparency / Morphometry / Sampling / Protection / Classification / Answers to Most Frequently Asked Questions / Glossary of Terms / Appendix A : Maximum, Minimum, and Mean Values / Appendix B : Phosphate Content of Common Cleansers …

Diagenesis Of Organic Matter In Las Vegas Bay And Bonelli Bay, Lake Mead, James W. Murray, Carolyn J. Jones, Kathy Kuivila, Jeff Sawlan

Publications (WR)

The interstitial water chemistry of the sediments of Las Vegas Bay and Bonelli Bay in Lake Mead has been studied as part of a comprehensive water quality study of those locations. Pore water and solid phase analyses were completed from four stations in Las Vegas Bay and two stations in Bonelli Bay. At both locations the pore water compositions and organic matter diagenesis in the sediments are dominated by sulfate reduction. This major role of sulfate reduction is unusual for lake sediments and reflects the fact that SO₄ is the major anion in the lake water. In addition, gypsum …

Chemical And Biological Structure Of Lake Mead Sediments, Richard T. Prentki, Larry J. Paulson, John R. Baker

Publications (WR)

Lake Mead has undergone a serious decline since Glen Canyon Dam was constructed 450 km upstream in 1963.

State fisheries management agencies are concerned that the decline was caused by water level fluctuations and more severe drawdowns during the bass spawning season, when the operation of Hoover Dam was altered during the post-Lake Powell period.

The construction of Glen Canyon Dam and formation of Lake Powell in 1963 drastically altered the natural discharge and temperature cycles and decreased suspended sediment and nutrient loading in the Colorado River inflow to Lake Mead. Recent studies indicate that these changes in nutrient loading …

Maine's Whitewater Rapids And Their Relevance To The Critical Areas Program, Janet Mcmahon

Maine Collection

Maine's Whitewater Rapids and Their Relevance to the Critical Areas Program

by Janet McMahon

Planning Report No. 74, Critical Areas Program, 184 State St., Augusta, Maine,

April, 1981 (additions made in October, 1981). Reprinted July, 1983.

Contents: Introduction / Natural History of Whitewater Rapids / Methods / Criteria / Results / Conclusions / General Evaluation of Whitewater Rapids for Inclusion on the Register of Critical Areas / Bibliography / Action Plan

Report No 41 - A Survey Method For Identifying Roadside Flora Suitable For Conservation In Western Australia, John K. Scott

Fisheries Research Reports

A survey method for identifying flora suitable for conservation alongside roads in south-western Australia was derived from an examination of characteristics of road verges. Two roads, from Midland to Toodyay and from Armadale to Bunbury, were examined. Width of verge, weed cover, soil disturbance, vegetation structure, presence of public utilities, evidence of fire and the type of adjoining land were measured at one mile (1.6 km) intervals on both sides of the road. Also recorded were aesthetic qualities such as stands of beautiful trees and sites of special interest, e.g. the presence of rare plants.

Three variables, percentage weed cover, …

The Distribution And Relative Abundance Of Aquatic Oligochaeta In The Upper Cache River System, Southern Illinois, In Relation To Water Quality, Mark Julian Wetzel

Masters Theses

Species composition, distribution, abundance, and water quality relationships of aquatic oligochaetes occurring in the upper Cache River system, southern Illinois were investigated. Forty-two taxa of oligochaetes including 16 naidids, 22 tubificids and representatives of the families Aeolosomatidae, Branchiobdellidae, Enchytraeidae, and Lumbriculidae were collected. Four species of oligochaetes new to Illinois, Limnodrilus psammophilus Loden, L. rubripenis Loden, Psammoryctides (Spencerius) californianus Brinkhurst, and Haemonais waldvogeli Bretscher were collected during this study. Another species of Limnodrilus new to science is reported here, as yet undescribed. The thesis that aquatic oligochaetes can be used as true water quality indicator organisms is rejected. It is …

Methods For Biological, Chemical, And Physical Analyses In Reservoirs, Penelope E. Kellar, Sherell A. Paulson, Larry J. Paulson

Publications (WR)

This manual contains detailed descriptions of biological, chemical and physical sampling and analytical procedures used at the Lake Mead Limnological Research Center. The manual was prepared in response to requests made by numerous individuals involved in the Las Vegas Valley Water Quality Program. This manual represents what we consider to be a reasonably complete compilation of methods useful in studying both general and specific limnological questions. While each section is sufficiently detailed to be of use to investigators with little experience in limnological methodology, the methods can be used on a wide variety of lakes and reservoirs, with relatively little …

Effects Of Changes In Surface Water Regime And/Or Land Use On The Vertical Distribution Of Water Available For Wetland Vegetation: Dynamic Model Of The Zone Of Aeration (Appendix To Part 1 Of Completion Report For Project A-023-Ark), Robert N. Maccallum, R. A. Sims

Arkansas Water Resources Center Technical Reports

Appendix to Part 1 of Completion Report for Project A-023-ARK

Effects Of Changes In Surface Water Regime And/Or Land Use On The Vertical Distribution Of Water Available For Wetland Vegetation: Dynamic Model Of The Zone Of Aeration (Part 1 Of Completion Report For Project A-023-Ark), Robert N. Maccallum, R. A. Sims

Arkansas Water Resources Center Technical Reports

A mathematical model by Green, simulating one-dimensional vertical ground-water movement in unsaturated soils of the prairie region of Kansas, has been adapted for use in a wetlands environment typified by the wetlands forest of Eastern Arkansas. The model consists of two second-order, non-linear, partial differential equations and an algorithm for their numerical solution. The original model was extended to include functions for seasonal changes in transpiration and for drainage of excess precipitation. Before the addition of the two functions, the model reliability was limited to one growth season.

Influence Of Las Vegas Wash Density Current On Nutrient Availability And Phytoplankton Growth In Lake Mead, John R. Baker, Larry J. Paulson

Publications (WR)

Density currents are commonly formed in reservoirs because of temperature or salinity induced density differences between inflowing and receiving waters. Anderson and Pritchard (1951) were among the first to demonstrate this in their investigations of density currents in Lake Mead. They found that the Colorado River formed an underflow in Lake Mead during the winter, an overflow in the spring and an interflow in the summer and fall. Wunderlich and Elder (1973) have since described the hydromechanics of these types of flow patterns, and density currents have been reported for several other large reservoirs (Carmack et al. 1979, Johnson and …

Nutrient Interactions Among Reservoirs On The Colorado River, Larry J. Paulson, John R. Baker

Publications (WR)

Interactions among physical, chemical and biological processes in reservoirs can significantly alter the characteristics of the discharge (Neel 1963, Wright 1967, Hannan 1979) that, in turn, can influence the ecology of the river downstream .(Ward and Stanford 1979). Investigations of the Colorado River, system reveal that reservoir-induced changes in the river can also affect downstream reservoirs. The formation of Lake Powell, in 1963 was accompanied by reductions in suspended sediment and nutrient loading and changes in the seasonal temperature and discharge cycles of the Colorado River. In this paper, we evaluate how these changes have influenced the nutrient and trophic …

Evaluation Of Possible Temperature Fluctuations From Proposed Power Modifications At Hoover Dam, Larry J. Paulson, John R. Baker, U.S. Water And Power Resources Service

Publications (WR)

There are several planned alternatives for increasing the generation capacity of Hoover Dam to help meet peak power demands. These alternatives include: (a) uprating the existing generating units, (b) replacing or adding one or more generating units and (c) adding reversible pumped-storage hydroelectric units. Since the existing generators are at the end of their economic life and have to be replaced, their uprating has been scheduled as routine maintenance. This will increase the generating capacity of the Hoover Dam powerplant from 1240 MW to 1810 MW, but the anticipated capacity for meeting power demand is 2300 MW. Therefore, modifications (alternatives …

Evaluation Of Impacts Associated With Reregulation Of Water Levels In Lake Mohave, Larry J. Paulson, John R. Baker, U.S. Water And Power Resources Service

Publications (WR)

The U.S. Water and Power Resources Service is considering reregulating Lake Mohave water levels to increase the net power benefit from Hoover Dam. Reregulation will not increase the generation capacity of the Hoover powerplant but it will enable the plant operation to be increased when the energy has greater monetary value. Energy generated at different times of the year has different market value, the highest being in January-March and July- September. By generating more power during these periods more net monetary benefit can be derived from Hoover Dam. The total volume of water released from Hoover Dam over an annual …

Report No 40 - Commercially Exploited Vacsular Plants Native In Western Australia: Census, Atlas And Preliminary Assessment Of Conservation Status, Barbara L. Rye, S. D. Hopper, L. E. Watson

Fisheries Research Reports

A census and atlas is provided of 1 119 native Western Australian plant species which were commercially exploited during 1977-79 in the cut plant, nursery or seed trades. The exploited species are concentrated in the vicinities of Perth and Albany, the two matin centres for the wildflower industry. Preliminary assessments of the conservation status of the exploited species are provided. Approximately r200 species are regarded as being rare, geographically or poorly collected, and further studies are recommended for these species to determine whether they are in danger of overexploitation.

The Limnological Status Of Lake Mead And Lake Mohave Under Present And Future Powerplant Operations Of Hoover Dam, Larry J. Paulson, John R. Baker, James E. Deacon, U.S. Water And Power Resources Service

Publications (WR)

The ever-increasing demand for energy in the southwest has led to a search for additional sources of power generation. Coal-fired powerplants currently provide most of the baseline energy in the southwest, but this must be supplemented with hydroelectric power during periods of peak demand. In order to provide additional peaking power, the U.S. Bureau of Reclamation is considering a number of projects to modify existing hydroelectric facilities, or add new facilities in the Lake Mead Recreation Area. The Hoover Powerplant Modification Feasibility Investigation was authorized by Congress on December 16, 1975 to determine the feasibility of: (i) adding one or …

A Guide To The Threatened And Endangered Vascular Plants Of The Lake Mead National Recreation Area, James S. Holland, Wesley E. Niles, Charles L. Douglas, Dennis R. Schramm

Publications (WR)

This illustrated guide was prepared to provide the botanical community, land managers, and other interested persons with a reference that describes and locates the twelve plant taxa currently being considered by the Fish and Wildlife Service for threatened or endangered status in or around the Lake Mead National Recreation Area. The guide is intended to assist managers of government agencies in determining the presence of these species and in defining management programs for their protection. The guide should be consulted prior to any construction project. If a potential conflict is identified, an onsite evaluation should be conducted early in the …

Influence Of Dredging And High Discharge On The Ecology Of Black Canyon, Larry J. Paulson, Theron G. Miller, John R. Baker, U.S. Water And Power Resources Service

Publications (WR)

The Water and Power Resources Service is considering dredging in Black Canyon to create a larger forebay to accommodate higher peak discharges and reverse flows for proposed modifications to Hoover Dam. The Black Canyon area from Hoover Dam to Willow Beach supports a heavily utilized trout fishery and is important habitat for the razorback sucker (Xyrauchen texanus) and possibly bonytail chub (Gila elegans). The Water and Power Resources Service initiated this investigation to determine what effect dredging and higher peak-discharges would have on the ecology of Black Canyon.

Metals In Apple Cider Produced And Marketed In Connecticut, Dennis W. Hill, Thomas R. Kelley, Gale R. Morrow, Sylvia W. Matiuck

Storrs Agricultural Experiment Station

No abstract provided.

Interference Suppression In Ho Fluorescence Detection, Thomas M. Hard, Robert J. O'Brien, T. B. Cook, G. A. Tsongas

Environmental Science and Management Faculty Publications and Presentations

In this Letter we report preliminary results on a sampling method that greatly reduces the above interferences relative to hydroxyl fluorescence.

Changing Fields: Agricultural Land Use Changes In Nebraska 1925-1974, Donald A. Wilhite

National Drought Mitigation Center: Faculty Publications

The series of graphs and maps which follow illustrate agricultural land use changes in Nebraska from 1925 to 1974. With these graphs and maps, the major agronomic crops of corn (dryland and irrigated), wheat, sorghum and soybeans are analyzed. The purpose of this analysis is to provide a pictorial history of Nebraska's ever-changing cropping system and, hopefully, to stimulate ideas and discussion with regard to trends and future directions. The Nebraska Water Resources Center is deeply interested in both the past and the future of Nebraska's agriculture because of the demands which agriculture places on the state's water resources. An …

Lake Mead And Lake Powell Salinity Reports, Cathy Lee, Steve Gazafy

Publications (WR)

The enclosed reports were compiled for the Colorado River Water Quality Office based on salinity data for Lake Mead and Lake Powell. According to the regional director of the office, the reports are not considered "polished" documents for public distribution. However, he considers them to be "interesting, rough appraisals of general trends that may be very important In our understanding the hydro-salinity system in the Colorado River."

Turbulence Spectra Above A Vegetated Surface Under Conditions Of Sensible Heat Advection, Raymond P. Motha, Shashi B. Verma, Norman J. Rosenberg

National Drought Mitigation Center: Faculty Publications

Spectra of vertical and horizontal velocity, air temperature and humidity fluctuations were analyzed from measurements made over a well-watered alfalfa crop under conditions of sensible heat advection. Vertical velocity and air temperature spectra as well as cospectra of momentum, sensible heat and water vapor were found to be dependent on atmospheric thermal stratification. These spectra and cospectra were shifted toward higher frequencies under advective as compared to lapse conditions. These results indicate that the predominant eddy sizes are relatively smaller under advective conditions. Humidity spectra, on the other hand, were independent of daytime thermal stratification conditions but were influenced by …

Potential Use Of Hydroelectric Facilities For Manipulating The Fertility Of Lake Mead, Larry J. Paulson, John R. Baker, James E. Deacon

Publications (WR)

Analysis of historical nutrient data for Lake Mead indicates that the fertility of the reservoir has decreased which may be the cause for a corresponding decline in the largemouth bass population. However, it appears that fertility can be manipulated by altering the operation of the dam. The depletion of nutrients in the euphotic zone by phytoplankton and subsequent accumulation in the hypolimnion during summer and fall provide a natural nutrient gradient from which water of varying fertility can be drawn for discharge. This combined with alterations in the depth or seasonal pattern of discharge can possibly be used to enhance …

Use Of Fishes And Macroinvertebrates In The Assessment Of Water Quality In An Illinois Stream Receiving Sewage Effluents, Robert George Mosher

Masters Theses

Kickapoo Creek is a medium sized, warm water stream located in the central part of Coles County, Illinois. The creek is the receiving stream for the sewage effluent of the cities of Mattoon and Charleston which recently began treating sewage to the tertiary level. In 1967-70, the fish population of the creek was intensively surveyed at a time when a less advanced method of sewage treatment was employed. This study provided a baseline of information from which a portion of the present study is founded.

Fish were collected from 5 sampling stations utilizing capture techniques comparable with those used in …