Catchment water storage variation with elevation

Abstract

One of the most important functions of catchments is the storage of water. Catchment storagebuffers meteorological extremes and interannual streamflow variability, controls the partitioningbetween evaporation and runoff, and influences transit times of water. Hydrogeological data toestimate storage are usually scarce and seldom available for a larger set of catchments. This studyfocused on storage in prealpine and alpine catchments, using a set of 21 Swiss catchments comprising different elevation ranges. Catchment storage comparisons depend on storage definitions.This study defines different types of storage including definitions of dynamic and mobile catchment storage. We then estimated dynamic storage using four methods, water balance analysis,streamflow recession analysis, calibration of a bucket‐type hydrological model Hydrologiska Byrans Vattenbalansavdelning model (HBV), and calibration of a transfer function hydrographseparation model using stable isotope observations. The HBV model allowed quantifying the contributions of snow, soil and groundwater storages compared to the dynamic catchment storage.With the transfer function hydrograph separation model both dynamic and mobile storage wasestimated. Dynamic storage of one catchment estimated by the four methods differed up toone order of magnitude. Nevertheless, the storage estimates ranked similarly among the 21catchments. The largest dynamic and mobile storage estimates were found in high‐elevationcatchments. Besides snow, groundwater contributed considerably to this larger storage.Generally, we found that with increasing elevation the relative contribution to the dynamic catchmentstorage increased for snow, decreased for soil, but remained similar for groundwater storage.