Cold Water Reservoir Research Articles

Investigation of thermal stratification in cisterns using analytical and Artificial Neural Networks methods

The thermal characteristics of an underground cold-water reservoir are investigated analytically and using Artificial Neural Networks (ANN). An analytical solution is developed for the temperature distribution in the reservoir by assuming a linearized boundary condition at the water surface. For the general non-linear boundary condition, the temperature distribution is modeled using ANN. Very good agreements between the analytical and ANN results at various times during the withdrawal cycle are observed, ensuring the accuracy of the analytical and ANN procedures. The results show that a stable thermal stratification is preserved in the reservoir throughout the entire course of withdrawal cycle. As one important outcome of this research, two different regions are observed inside the thermally stratified tank during discharge cycle. The bottom region with a linear temperature distribution and the upper one in which a nearly exponential thermal stratification are developed. During withdrawal cycle, the outside temperature reaches as high as 42 °C, while cool water with the temperature varying from 12 to 13 °C is easily available from the underground water reservoir under investigation.

Thermal characteristics of an underground cold-water reservoir: Analytical and experimental studies

The thermal characteristics of an underground cold-water reservoir are investigated analytically and experimentally. An analytical solution is developed for the temperature distribution in the reservoir by assuming a linearized boundary condition at the water surface. The results are compared with the experimental measurements which have been conducted in a cistern located in the city of Yazd. Very good agreements between the analytical and the experimental results at various times during the withdrawal cycle are observed, ensuring the accuracy of the analytical solution obtained for the linearized boundary condition. The results show that a stable thermal stratification is preserved in the reservoir throughout the entire course of the withdrawal cycle. During this period, the outside temperature reaches as high as 42 °C, while cool water with the temperature varying from 12 to 13 °C is easily available from the underground water reservoir under investigation.

LIFE HISTORY ATTRIBUTES OF WHITE SUCKER (CATOSTOMUS COMMERSONI) IN LAKE TANEYCOMO AND ASSOCIATED TRIBUTARIES IN SOUTHWESTERN MISSOURI

Abstract Spawning season of the white sucker (Catostomus commersoni) in tributaries of Lake Taneycomo, a coldwater reservoir of the White River system in southwestern Missouri, lasted from early April to late May in 1994 and 1995. Collection of fish larvae and spawning activities of adult white sucker indicated that spawning occurred in all tributaries of the lake. We did not observe evidence of spawning in the lake. White suckers began to mature at age 3 and a total length of 275 mm. A larger proportion of males matured at an earlier age and length, but females lived longer and reached larger sizes. Mortality rates were higher for mature males than females. Both sexes exhibited high mortality after age 8. Females were more abundant than males (1.94 to 6.50: 1 F:M) in the upper lake throughout the year, while males were more abundant in Bull Creek (0.27 to 0.30:1 F:M), a major tributary, during the spawning season. Fecundity increased with fish size, ranging from approximately 5,000 to 59,000 eggs. Growth...

Subsidence and Stress Change in the Cerro Prieto Geothermal Field, B. C., Mexico

Previous works have shown that ground deformation and seismicity in the Cerro Prieto geothermal field (CPGF) are due to both tectonics and field exploitation. Here, we use information about current tectonics and data from precision leveling surveys, to model tectonic and anthropogenic subsidence. Our results show that tectonic subsidence constitutes only ∼4% of the measured subsidence. Anthropogenic subsidence was evaluated using a model of rectangular tensional cracks, based on the hydrological model of the field, together with the Coulomb 2.0 program. From the resulting values of the fissure parameters and from extraction and injection data, we calculate that the volume changes caused by closure of the geothermal and cold water reservoirs account for only ∼3% and ∼7%, respectively, of the volume change which should occur due to extraction. Since 18% of the extracted fluids are reinjected, external recharge must compensate for about 72% of the expected volume reduction. An analysis of the changes in Coulomb stress caused by exploitation of the geothermal field suggest that even though the anthropogenic stresses account for only a fraction of tectonic stresses, they are large enough to trigger seismicity.

Tracking Trophic Interactions in Coldwater Reservoirs Using Naturally Occurring Stable Isotopes

Abstract We measured signatures of naturally occurring stable isotopes of carbon (13C) and nitrogen (15N) in important invertebrate and fish taxa in two coldwater reservoirs in Colorado that had different food webs. One reservoir, Lake Granby, contained a large population of an opossum shrimp, Mysis relicta, and the other, Blue Mesa Reservoir, did not. We compared temporal dynamics of isotopic signatures of all taxa between lakes to quantify sources of variability in consumer signatures and to assess potential turnover rates of isotopic signatures in the top predator. Stable isotope signatures varied little across season or body size within most taxa, but large differences across reservoirs were observed. Nitrogen signatures of lake trout Salvelinus namaycush were enriched in larger individuals in both reservoirs, indicating increasing trophic position with body size. Carbon signatures in lake trout livers were consistently lower than those in muscle samples but did not change more rapidly than muscle sig...

Validation of Age Estimates from White Sucker Otoliths

White suckers Catostomus commersoni were collected by electroshocking from Lake Taneycomo, a coldwater reservoir in southwest Missouri, to validate the use of otoliths as a yearly estimator of age. Otoliths (lapillae) were sectioned through the transverse plane for age estimation. Age validation was by edge analysis, whereby the formation of an annulus at the growing edge of the otolith was tracked throughout the year. Results indicated that only one annulus was formed per year. It was determined that otoliths are a reliable estimator of yearly age for white suckers age 2–18 in Lake Taneycomo.

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.