Water Balance of Cuba Karst Areas

Abstract

The process and conditions of karst formation and its types have already been studied. As this natural phenomenon is heterogeneous and changeable, it is rather difficult to estimate how karst influences the river runoff, infiltration capacity and water balance in catchment areas. This study is based on the approach used by the author in his researches on water balance. The approach helps to estimate how karst influences infiltration capacity. The study is also based on the genetic runoff theory, firstly introduced by A.N. Befany. This theory takes into account the conditions of water absorption into soil when considering water balance. That is why it suggests three types of absorption: seepage within the period of water formation RT, seepage after termination of runoff due to amounts of water which are left in depressions R0, seepage within the period of runoff recession after water formation RT. In order to consider the influence of karst on hydrological characteristics, this study uses the values of surface detention depth after termination of runoff due to amounts of water left in depressions R0. This parameter is the key parameter in this study as it helps to estimate the influence of caverns on infiltration capacity. However, the amount of water detained in closed depressions R0 can partly include both surface runoff and water detained in caverns. This study helps to distinguish these two types of water. The article also shows the graph dependence between the cavern volume filled with water and infiltration capacity. This dependence makes it possible to estimate how karst influences infiltration capacity and runoff and water balance as well. The analysis helps to determine quantitative influence of karst on infiltration capacity. The results of the research must be considered as preliminary ones as it is necessary to analyze more catchment areas, using observation data from the Pinar del Rio and Matanzas provinces.