Climatic trends, water balance and Lake Patzcuaro, a tropical high altitude lake

The results of a hydrological study are presented with implications for water budget and regional climatic fluctuations. Lake Patzcuaro is a tropical freshwater high altitude lake located al the southern edge of the Mexican Plateau. The lake originated from tecto-volcanic processes associated with the Eje Neovolcanic Transversal during the late Tertiary and Quaternary. The lake is an endhoreic basin and the annual water balance is primarily controlled by differences between rainfall and evaporation. Since annual evaporation is higher than rainfall, it is considered that net water inputs to the lake come as seepage from the drainage area. However,. by using a simple mass simulation model it is illustrated that the contribution of seepage is being reduced due to the continuous deterioration of the catchment area. (C) 1997 INQUA/Elsevier Science Ltd.