A curve number approach to formulate hydrological response units within distributed hydrological modelling

Abstract

Abstract. We propose a systematic framework for delineating Hydrological Response Units (HRUs), based on a modified Curve Number (CN) approach. The CN-value accounts for three major physiographic characteristics of a river basin, by means of classes of soil permeability, land use/land cover characteristics, and drainage capacity.

On the Ability of LIDAR Snow Depth Measurements to Determine or Evaluate the HRU Discretization in a Land Surface Model

“…The results stress the necessity of an adequate and objective discretization approach in alpine catchments, that reflects dominant snow depth patterns and thus allows for an appropriate representation of key processes in the used model to gain optimal simulation results. Unlike previously presented concepts for an objective HRU delineation [8,[12][13][14], the here presented approach directly links the HRU delineation to the snow cover as an internal state of alpine hydrology. The presented method makes use of terrestrial LIDAR data.…”

“…The resulting HRU scheme is therefore neither objective nor reproducible by other scientists. Approaches to objectively delineate HRUs usually use surface and subsurface characteristics (e.g., geology, soil type, vegetation, slope, aspect) that are known to influence hydrological processes [8,[12][13][14]. Yet, the disadvantage of these approaches is that they do not directly represent the hydrologically dominant component or processes of the water cycle.…”

“…The presented approach of delineating HRUs is the first that directly links the physiographic properties to the snow cover as the dominant water cycle component of a high alpine catchment. In contrast, previously presented approaches only make use of surface and subsurface information [8,[12][13][14]. A similar approach has been presented for a low land catchment using remotely sensed land surface temperature [36].…”

Coupling the water footprint accounting of crops and in-stream monitoring activities at the catchment scale

“…In order to perform a soil-water balance, calibrate the leaching-runoff fraction and finally assess the total WF of catchment-scale crops, the watershed was preliminarily divided into land-use systems (LUSs), defined as areas with similar land use, soil characteristics and precipitation amounts [ 25 , 26 ]. Therefore, land-use maps, soil maps and rainfall zones (Thiessen polygons) can be intersected by means of specific GIS tools.…”

“…The P n,i is determined as follows: , where P i (mm) is the total precipitation amount. Thiessen polygons are built and rainfall zones are distinguished [ 25 , 26 ]. ET c,adj,i is determined according to Eq.…”