Alterations of the hydrologic regime and their effects in the phosphorus and phosphates in Lake Chapala, Mexico [modificaciones en el régimen hidrológico y sus efectos en la acumulación de fósforo y fosfatos en el Lago de Chapala, MéXico]

As a result of water inflow reduction and contamination, as well as water volume loss due to water extraction, since several years ago Lake Chapala undergoes a process of cultural eutrophication due to excess of nutrients, placed in evidence by the grow of abundant aquatic vegetation in the mouth of the Lerma River and in the lake itself. Application of non conventional techniques based in a cell model to obtain a mass balance for phosphorus (P) and phosphates (PO4 -3) demonstrated that the main source of this nutrients in the lake is the Lerma River, due to the fact that this river receives municipal, agricultural, and industrial waste water discharges, with limited treatment, along the basin. This work proposes a rigorous method to assess P and PO4 -3 accumulation in Lake Chapala. The results show that the lake lost its ability to remove total P since 1983 and PO4 -3 starting in the period 1977-1978. At the same time it was estimated that the average amount of PO4 -3 in the lake represents 67.6% of total P, which maintains a high biological availability of this nutrient in the water column of the lake

Alterations of the hydrologic regime and their effects in the phosphorus and phosphates in Lake Chapala, Mexico [modificaciones en el régimen hidrolZapotitlángico y sus efectos en la acumulación de fósforo y fosfatos en el Lago de Chapala, MZapotitlánXico]

As a result of water inflow reduction and contamination, as well as water volume loss due to water extraction, since several years ago Lake Chapala undergoes a process of cultural eutrophication due to excess of nutrients, placed in evidence by the grow of abundant aquatic vegetation in the mouth of the Lerma River and in the lake itself. Application of non conventional techniques based in a cell model to obtain a mass balance for phosphorus (P) and phosphates (PO4 -3) demonstrated that the main source of this nutrients in the lake is the Lerma River, due to the fact that this river receives municipal, agricultural, and industrial waste water discharges, with limited treatment, along the basin. This work proposes a rigorous method to assess P and PO4 -3 accumulation in Lake Chapala. The results show that the lake lost its ability to remove total P since 1983 and PO4 -3 starting in the period 1977-1978. At the same time it was estimated that the average amount of PO4 -3 in the lake represents 67.6% of total P, which maintains a high biological availability of this nutrient in the water column of the lake

Estimation of trophic states in warm tropical lakes and reservoirs of Latin America by using GPSS simulation

This paper proposes a stochastic simulation model to determine the boundaries of the trophic states of warm-water tropical lakes and reservoirs in Latin America based on statistical correlation and MonteCarlo techniques. The model was developed using GPSS as a discrete simulation language and calibrated by correlating a set of state variables of 27 Latin American lakes and reservoirs monitored by the Pan American Center of Sanitary Engineering and Environmental Sciences (CEPIS). In order to warrant a better stability in the resultant probabilistic behavior of the dependent variable, 10000 new virtual water bodies with different trophic states were generated to produce a trophic state index based on the total phosphorus concentration. Based on the obtained results, it is concluded that the applied methodology is appropriate to determine the boundaries of the trophic states of warm-water tropical lakes and reservoirs and is also able to generate results similar to those obtained using the existing applied estimation techniques. � 2006 Asociaci�n Interciencia

Simulation des Abflusses der Weser in Anlehnung an Klimarechnungen des DKRZ (Vorlaufprojekt) Abschlussbericht

Available from TIB Hannover: F95B364+a+b / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

Eintrittswahrscheinlichkeit von Wasserstaenden und Abfluessen im tidebeeinflussten Bereich von Fluessen

Available from TIB Hannover: F94B0888 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Solids distribution in Lake Chapala, Mexico

Lake Chapala is the largest natural water body in Mexico and also one of the most important shallow lakes in Latin America. For the past several years it has suffered various environmental problems such as the upstream overuse of water, contamination, and sedimentation. For the past 10 years the lake has had less than 50 percent of its historical water level over the past century. No criteria are reported in the literature that establish a water storage volume that will guarantee water quality conditions necessary for the survival of the lake. After determining the behavior of total solids concentrations in relation to the variations in the lake's depth, we proposed a minimum water column height of 5.0 m, representing a storage volume of about 5,000 Mm3. This volume would result in the recommended water quality standards for total dissolved solids. Calculated distribution maps show that the total solids concentration in the lake has increased since the end of the 1970s. The solids are primarily concentrated in the eastern part of the lake, as a consequence of the high solids discharged from the Lerma River, its main tributary

Solids distribution in Lake Chapala, Mexico

Lake Chapala is the largest natural water body in Mexico and also one of the most important shallow lakes in Latin America. For the past several years it has suffered various environmental problems such as the upstream overuse of water, contamination, and sedimentation. For the past 10 years the lake has had less than 50 percent of its historical water level over the past century. No criteria are reported in the literature that establish a water storage volume that will guarantee water quality conditions necessary for the survival of the lake. After determining the behavior of total solids concentrations in relation to the variations in the lake's depth, we proposed a minimum water column height of 5.0 m, representing a storage volume of about 5,000 Mm3. This volume would result in the recommended water quality standards for total dissolved solids. Calculated distribution maps show that the total solids concentration in the lake has increased since the end of the 1970s. The solids are primarily concentrated in the eastern part of the lake, as a consequence of the high solids discharged from the Lerma River, its main tributary