The Upper Pearl River and its watershed is the main source of water flowing into the Ross Barnett Reservoir, the City of Jackson’s major drinking water supply. Groundwater characterization of the watershed was achieved by analyzing viable groundwater wells and a groundwater spring best representing the land use and land cover extraction map created. Incorporated surface geology demarcated specific stratum, helping describe the different hydrogeochemical interactions observed. Analysis indicated that chloride and nitrate exceeded the Maximum Contamination Levels (MCLs) possibly contributing to eutrophication in the reservoir. Several of the metal and trace elements analyzed were below the MCLs, with the exceptions of manganese, aluminum, and iron. No pharmaceuticals, pesticides, or industrial residues exists in Carthage and Philadelphia’s groundwater, the largest cities in the region. Conclusively, the watershed’s groundwater contains high concentrations of anions along with metal concentrations associated with the ferruginous sandy-clay surface geology moving closer to the reservoir.

FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / O processo de armazenamento de Ãgua em regiÃes semi-Ãridas tem se tornado um considerÃvel meio de reduzir a escassez deste recurso natural. Assim, à comum em regiÃes, com caracterÃsticas do Nordeste Brasileiro, a construÃÃo de grandes reservatÃrios, que tem servido para atender, com certa regularidade, demandas para os mais diversos usos. Por outro lado, o armazenamento de Ãgua em reservatÃrios acaba tornando essas massas lÃquidas vulnerÃveis a um maior risco de degradaÃÃo. Como se sabe, a Ãgua armazenada fica sujeito a longo tempo de residÃncia, permitindo assim com que algumas importantes reaÃÃes, tanto do ponto de vista quÃmico, como biolÃgico, possam ocorrer. Estas reaÃÃes, associadas com alguns lanÃamentos de efluentes, provenientes de zonas urbanas, Ãreas industriais e zonas rurais, acabam por acelerar o processo de envelhecimento dos reservatÃrios, conhecido como âprocesso de EutrofizaÃÃoâ, que depende, fundamentalmente, da disponibilidade de nutrientes no interior dos reservatÃrios. Este trabalho estudou, atravÃs de pesquisa de campo, associada com uma metodologia de cÃlculo de Ãndices de Estado TrÃfico Modificado e Ãndice de Qualidade de Ãgua, as condiÃÃes ambientais do ReservatÃrio Acarape do Meio, no Estado do CearÃ, na busca de uma identificaÃÃo das principais transformaÃÃes nos seus nÃveis trÃficos, bem como, na identificaÃÃo das principais causas de um possÃvel processo de eutrofizaÃÃo do mesmo. Para isso foram utilizados dados de campo em um perÃodo de 2001 a 2006, o que permitiu conhecer as caracterÃsticas pertinentes à estratificaÃÃo deste corpo hÃdrico, no que diz respeito à temperatura e a estratificaÃÃo quÃmica de suas Ãguas. TambÃm, tendo em vista os vÃrios pontos de coletas de dados, foi possÃvel apresentar resultados relativos ao Ãndice de Estado TrÃfico e ao Ãndice de Qualidade de Ãgua, em uma distribuiÃÃo espacial do reservatÃrio, mostrando, assim, os vÃrios pontos crÃticos do mesmo. Nas questÃes pertinentes ao Ãndice de Estado TrÃfico foram usados dois cÃlculos, sendo para o primeiro usado, apenas, a clorofila-a e o fÃsforo, enquanto que no segundo cÃlculo foram utilizados, alÃm dessas duas substÃncias, o ortofosfato solÃvel presente naquelas Ãguas. Os resultados mostram que hà uma forte variabilidade da qualidade das Ãguas deste reservatÃrio, mas que, nos anos de 2004 e 2005, suas Ãguas atingiram um nÃvel hipereutrÃfico, o que representa a presenÃa de um forte aporte de nutrientes provenientes das entradas do reservatÃrio e, provavelmente, das zonas rurais que existem em torno do mesmo. Os resultados mostraram ainda que, mesmo que a variaÃÃo vertical de temperatura nÃo seja tÃo significativa no interior do reservatÃrio, hà uma forte presenÃa de estratificaÃÃo quÃmica nas camadas mais profundas deste corpo hÃdrico. / The process of storage of water in semi-arid regions has become a considerable way of reducing the shortage of this natural resource. Like this, it is common in areas with characteristics of the Brazilian Northeast, the construction of great reservoirs that has been being to assist, with certain regularity, demands for the most several uses. On the other hand, the storage of water in reservoirs bring some vulnerabilities to the water, concerning with the degradation risk. As it is known, the stored water is subject to long residence times, allowing the appearance of some important chemical and biological reactions. These reactions, associated with some sewage releases, that come from urban, industrial, and rural areas, promote the accelerating the process of aging of the reservoirs, known as Eutrophication Process, that depends, fundamentally, of the presence of nutrients inside the reservoirs. This work studied, through field data, associated with a methodology of calculation of Modified Trophic State Index and the Water Quality Index, the environmental conditions of the Acarape do Meio Reservoir, in the State of CearÃ, trying to identificaty the main transformations in their trophic levels, as well as, the identification of the main causes of a possible process of eutrophization of it. The data cover the years 2001 through 2006. With that, it was possible to know the characteristics concerning with the stratification this body of water, with respect to temperature and the chemical process. Also, considering the several points of collections of data, it was possible to present results concerning with the Trophic State Index and the Water Quality Index, a long of the all surface of the reservoir, showing, like this, the several critical points of it. With respect to the Trophic Level Index, two calculations were used, being for the first used, just, the chlorophyll a and the phosphors, while in the second calculation they were used, besides those two substances, the present soluble orthophosphate in those waters. The results show that there is a strong variability of the quality of the waters of this reservoir, but that, in the years of 2004 and 2005, their waters reached a hipereutrophic level, that represents the presence of a fort presence of nutrients coming of the entrances of the reservoir and, probably, of the rural areas that exist around the it. The results showed yet, even if the vertical variation of temperature is not so significant inside the reservoir, there is a strong presence of chemical stratification in the deepest layers of this body of water.

Many multipurpose reservoirs are situated in the low mountain range of Germany. Most of them are necessary for drinking water supply and flood protection as well. Other utilizations are recreation, water power and the downstream low water regulation during dry seasons. The operation rules of the reser-voirs have to be optimized to meet the different requirements of use. One tool within this framework is a management system for river basins including all reservoirs and their specific operation rules affecting the downstream reaches. As an optimization objective for instance the minimization of inundation risks can be defined. In this case the risk can be defined as hydraulic and hydrologic safety of the reservoir itself and the risk due to inundation and damaging in the downstream regions. Considering the European Water Framework Directive the ecological aspect of reservoir management is one more point in the optimization process. To es-tablish a pilot project the software TALSIM will be applied to river catchments in the ore mountains (Saxony).

Water quality models in the Colorado River Basin have been developed for the basin, river, and individual reservoirs. They are used to support water quality programs within the basin. The models are periodically reviewed and updated to improve the accuracy of simulations. Improving the usefulness of the Lake Powell model, one of the key reservoirs in the basin, is the subject of this study. Lake Powell is simulated using a hydrodynamic and water quality model, CE-QUAL-W2. Previously the model has been used at Lake Powell to simulate hydrodynamics, temperature, and total dissolved solids with a reasonable degree of accuracy. An additional parameter, dissolved oxygen, will be added to the simulations and then calibrated with observed data to verify accuracy. Dissolved oxygen distributions in Lake Powell vary seasonally and change under different hydrologic cycles. They are a function of physical, biological, and chemical processes. Few measurements of these processes in Lake Powell exist. To compensate for the lack of data an empirical method of loading oxygen demand to the model is developed and tested. Observed limnological processes in the reservoir guide the development of the empirical methods. The methods are then tested in 16 year model simulations and compared with dissolved oxygen measurements from the 16 year period. By accurately reproducing the dissolved oxygen distributions the Lake Powell model will have improved accuracy and also broaden its usefulness.