Recession flow analysis as a suitable tool for hydrogeological parameter determination in steep, arid basins

• A recession flow analysis is carried out in 6 arid basins in North-Central Chile.
• Basin-wide hydrogeological parameters are determined for the studied basins.
• The method provides a cost-effective approach to obtain hydrogeological information.

The analysis of baseflow recession of streamflow has been widely used in the evaluation of basin scale parameters because the required data are inexpensive to acquire, and the method is easy to use and generally gives good results. A literature review, however, shows that few studies have examined the applicability of recession methods to arid basins, particularly those set in mountainous landscapes. In this study, we apply a recession method that uses a non-dimensional theoretical curve matching technique to evaluate basin-wide, spatially-averaged hydraulic parameters for several watersheds (Culebrón, Punitaqui, Valle Hermoso, Hurtado, Chalinga, and Camisas), taking as case of study the Coquimbo Region, an arid, mountainous territory with steep topography in North-Central Chile. The studied watersheds range from 200 to 1500 km2. Results show hydraulic conductivity values in a reasonable range, i.e., 10−4 to 10−6 m s−1, rather close to those reported in the few existing studies for some of the basins. The method also yields estimates on the order of 10−5 for drainable porosity, with no major differences between the basins. The recession flow analysis provides a cost-effective approach to obtaining bulk hydrological parameters in arid and semi-arid steep basins such as those of the Coquimbo Region and elsewhere.