BUFFER STRIPS TO PROTECT WATER SUPPLY RESERVOIRS: A MODEL AND RECOMMENDATIONS1

ABSTRACT: Buffer strips are undisturbed, naturally vegetated zones around water supply reservoirs and their tributaries that are a recognized and integral aspect of watershed management. These strips can be very effective in protecting the quality of public potable water supply reservoirs by removing sediment and associated pollutants, reducing bank erosion, and displacing activities from the water's edge that represent potential sources of nonpoint source pollutant generation. As part of a comprehensive watershed management protect for the State of New Jersey, a parameter-based buffer strip model was developed for application to all watersheds above water supply intakes or reservoirs. Input requirements for the model include a combination of slope, width, and time of travel. The application of the model to a watershed in New Jersey with a recommended buffer strip width that ranges from 50 to 300 feet, depending upon a number of assumptions, results in from 6 to 13 percent of the watershed above the reservoir being occupied by the buffer.     

基于洪水资源化的水库汛限水位调整及其风险管理

在论述“洪水资源化”概念和调整水库汛限水位所涉及的影响因素的基础上, 构建了汛限水位 调整后的风险和效益评价指标体系及其估算方法, 以及论述了水库汛限水位调整的风险管理对策。 以五强溪大型水库为例, 综合评价了在不同汛限水位方案下所带来的风险及效益, 并引入优选模糊 理论方法来合理调整汛限水位。通过综合分析认为, 五强溪水库在主汛期将汛限水位从现行的 98.00m 提高到100.00m 的方案是可行的, 它在防洪风险增加不多的情况下, 可将有可能被排泄的 1.85×108m3 洪水转化为有效利用的水资源, 显然, 将大型水库提高汛限水位超蓄洪水是实现洪水资 源化的重要手段, 但必须是在加强水库实时调度风险管理的提前下实施。     

Trophic relationships in the recently impounded Bagré reservoir in Burkina Faso

The trophic dynamics of Bagré reservoir which has been recently impounded in Burkina Faso was based on the data collected during 1997–1998 period using the Ecopath model and software. Total fish biomass is 22.63 t km⁻² and mainly represents trophic levels (TLs) 2 and 3. The trophic food chain is relatively long and the overall transfer efficiency is quite low. Grazing foodweb based on primary producers is prominent in the reservoir ecosystem and detritus plays a less significant role. Seasonal and long-term variations in water quality have significant influences on the lower TLs clearly showing a bottom-up functioning of the ecosystem. Environmental degradations, such as siltation occurring in the lake, suggest possible risks in limiting ecosystem productivity.     

MASS BALANCE MODEL ESTIMATION OF PHOSPHORUS CONCENTRATIONS IN RESERVOIRS1

ABSTRACT: Mass balance models have been common tools in lake quality management for some years. However, verification for use on reservoirs, especially in the Western United States, has been seriously lacking, In this study, such a verification is attempted using data from the U.S EPA National Eutrophication Survey. Several models from the literature are compared for accuracy in application to the western reservoir data. Model standard error and correlation between estimated and observed reservoir phosphorus concentrations are the Criteria used for comparison. Standard errors am further used to calculate uncertainty of trophic state classification based on estimated phosphorus concentration. The model proposed by Dillon and Rigler (1974) proved most accurate, with a correlation coefficient of 0.86 and standard error of 0.2, based on logarithmic transformed values. Deficiencies in the other models appear to & from coefficients fit to lake data and from inappropriate model formulation.     

Secchi Disc Relationships1

ABSTRACT: The problem of estimating bulk light extinction coefficients in surface water impoundments is examined. It is shown that the bulk extinction coefficient can be accurately estimated from the Secchi disc depth. In addition, the equation derived is significantly different from that derived by Poole and Atkins in 1929. This empirical expression for the extinction coefficient is then used to develop a semiempirical expression for the euphotic depth as a function of the Secchi disc depth.     

EFFECTS OF WATER DRAWDOWN ON THE FAUNA IN SMALL COLD WATER RESERVOIRS1

ABSTRACT: Two small cold water reservoirs with stable water levels were compared with two reservoirs scheduled for complete drawdown to determine the effects of drawdown on invertebrate abundance and fish abundance and density. An extensive literature review supplemented the results with other applicable information. No conclusive evidence of effects of drawdown on invertebrates or fish was found. Characteristics of a reservoir and its drainage basin which obscure or lessen drawdown effects are discussed. Analysis and observation of drawdown procedures showed that duration and scheduling of draw-down periods are important in determining whether drawdown will be harmful to fauna in a given reservoir.     

PRELIMINARY DESIGN AND COST ESTIMATING FOR RESERVOIR PROJECTS1

ABSTRACT: In estimating the costs of a reservoir project, it is difficult to produce accurate costs without performing a detailed design and quantity takeoff. The computerized procedure presented in this article provides a method for determining these planning level costs quickly and easily, while maintaining reasonable accuracy.     

RECREATION AT DRINKING WATER RESERVOIRS IN MASSACHUSETTS: A SURVEY OF WATER MANAGERS1

The purpose of this study was to identify attitudes toward the recreational use of drinking water reservoirs in Massachusetts among municipal water supply managers in the state. Compared to the findings of recent studies assessing the attitudes of the general public, water officials were found to advocate highly restrictive views. No officials said that recreation was an insignificant source of water supply pollution; however, opinions were not found to be related to respondents' exposure to the literature on the topic. The majority were not, in fact, familiar with the literature assessing the impact of recreation on water supply reservoirs.     

THE ECONOMIC FEASIBILITY OF DUAL PURPOSE NUCLEAR DESALINATION OF GROUND WATER1

ABSTRACT: The economic feasibility of a large scale dual purpose (desalting water and power production) facility were evaluated. Although a site in the Tularosa basin of southern New Mexico was chosen as a case study for this analysis, it is believed that the approach and consequential results would be applicable to alternative sites in the Southwest. The basic project evaluated included: a) a ground water well field; b) a dual purpose, nuclear, desalination plant; c) a mineral recovery plant; and d) a reservoir for recreation and irrigation storage. Principle project outputs included electrical power, minerals, recreation, and water for either irrigated agricultural production or export to an adjoining river basin. Two alternative project designs were developed for detailed analysis. The first alternative encompassed all major project components. The results, in discounted net values used to assess the feasibility of the project, were essentially negative; that is, values were less than zero for full scale development. The net benefits ranged from $-986.57 million at a 5 percent discount rate, to $-1,137.528 million at a discount rate of 10 percent. In the second alternative, exportation of the desalted water from the Tularosa basin to two adjacent rivers was analyzed with somewhat better net benefits, ranging from $-382,527 million to $-478,612 million at the 5 and 10 percent discount rates.     

MULTIVARIATE CLASSIFICATION OF SMALL ORDER WATERSHEDS IN THE QUABBIN RESERVOIR BASIN,MASSACHUSEVFS1

ABSTRACT: A multivariate approach was used to analyze hydrologic, geologic, geographic, and water-chemistry data from small order watersheds in the Quabbin Reservoir Basin in central Massachusetts. Eighty three small order watersheds were delineated and landscape attributes defining hydrologic, geologic, and geographic features of the watersheds were compiled from geographic information system data layers. Principal components analysis was used to evaluate 11 chemical constituents collected bi-weekly for 1 year at 15 surface-water stations in order to subdivide the basin into subbasins comprised of watersheds with similar water quality characteristics. Three principal components accounted for about 90 percent of the variance in water chemistry data. The principal components were defined as a biogeochemical variable related to wet. land density, an acid-neutralization variable, and a road-salt variable related to density of primary roads. Three subbasins were identified. Analysis of variance and multiple comparisons of means were used to identify significant differences in stream water chemistry and landscape attributes among subbasins. All stream water constituents were significantly different among subbasins. Multiple regression techniques were used to relate stream water chemistry to landscape attributes. Important differences in landscape attributes were related to wetlands, slope, and soil type.