The effects of changes in vegetative cover on river flows in the Purapel river basin of central Chile

Abstract

The distribution of peak river flows was studied over the period 1960–2000 in the watershed of Purapel River (Maule Region, Chile) in order to evaluate the relationship of these flows to vegetation cover. Maximum annual and summer flows, between decades and between periods, monthly and yearly were compared with multi-temporal analysis for 1955, 1978 and 1997. The evolution of peak flows over the period was irregular, and did not show significant differences in the majority of comparisons. The variation in vegetation cover during the study period was caused by migration from native forests to commercial plantation of Pinus radiata (D. Don). The data from this watershed does not permit the conclusion that variation in peak flows is due to variation in vegetative cover. The peak flows are more highly dependant on precipitation values. For the watershed and period of study the native forest and plantations of P. radiata (D. Don) have a similar hydrological behavior.