Hydrology of the Lerma-Chapala Watershed

Epilithic diatom communities of selected streams from the Lerma-Chapala Basin, Central Mexico, with the description of two new species

“…This basin is one of the most important centers in the country for agriculture and industry, and has a population of more than 15 million inhabitants ( Wester et al 2005 , Cotler et al 2006 ). But the Lerma-Chapala Basin is also one of the most environmentally degraded basins in the country, facing serious water related issues because of overexploitation and pollution of surface and underground waters ( Aparicio 2001 , Wester et al 2005 ).…”

Long-term change in the biotic integrity of a shallow tropical lake: A decadal analysis of the Lake Chapala fish community

“…Of secondary importance are human actions that modify the physical ecosystem From 1979 to the mid-1980s, a second period of substantial water-level decline occurred that coincided with a reduction in the mean annual rainfall (680 mm). At the same time, however, the constructed reservoir storage capacity in the watershed increased from 1817 to 3678 million cubic meters, and the average irrigated area had grown from 250,000 to ∼650,000 ha, mainly due to an increase in groundwater irrigation (Aparicio 2001, Wester et al 2001). …”

“…Two closely related arguments support the role of human water use in reduced lake levels. First, despite an increase in rainfall, the inflow value from the Rio Lerma dropped by more than half due to over exploitation upstream: inflow from 1922 to 1969 was 1646 hm 3 , and average annual rainfall was 706 mm; inflow from 1970 to 2001 was 738 Mm3, and average annual rainfall was 697 mm (Aparicio 2001). Second, reduced inflow is associated with an increase in the hydraulic residence time, with a maximum value of 40 years calculated in 1989 and an average of 15 years for the last 3 decades; the average before the 1970s was only 5 years (de Anda and Shear 2001).…”

“…When coupled with other anthropogenic impacts, there can be major effects on the fish community and associated fisheries. Large, shallow, and tropical Lake Chapala, located in central Mexico, provides a clear example of a human-altered water cycle and serves as a model for assessing fish community responses to extreme hydro- * Corresponding author: rmoncayo@hotmail.com logic fluctuations (Mestre 1997, Aparicio 2001. Lake Chapala has experienced in the last decades a continuing and drastic decline in water quantity and quality as a result of human activities (de Anda and Shear 2001).…”

Time Delay Evaluation on the Water-Leaving Irradiance Retrieved from Empirical Models and Satellite Imagery

“…The river belongs to one of the largest basins in the country, which has a surface of 47,116 km 2 and a mean annual surface runoff of 4742 Hm 3 [42]. The Lerma river carries a great amount of solids generated by erosive processes, mainly caused by poor management of soil resources [43,44]. The river also transports contaminants from upstream towns to the lake due to the agricultural, livestock and industrial activities; many of these effluents are not treated and constitute a potential threat to the ecosystem of the lake and further downstream [45,46].…”