Estimation of the HEC-HMS model parameters in data-scarce regions. Application to the Ouergha watershed (Sebou, Morocco)

Hasna Moumni,Laila Stour,Abdellatif Ahbari,Karima Sebari,B El Mansouri,N Mejjad,N Satour,M Ben-Daoud,A Moumen,M El Bouhaddioui,Y Bouslihim,I Elhassnaoui,L El Mezouary,B El Mahrad,G Moroşanu

doi:10.1051/e3sconf/202131405002

Abstract

The availability, accessibility and quality of data are significant obstacles to hydrological modelling. Estimating the initial values of the hydrological model´’ ’s parameters is a laborious and determining task requiring much attention. Geographic information systems (GIS) and spatial remote sensing are prometting tools for processing and collecting data. In this work, we use an innovative approach to estimate the HEC-HMS hydrological model parameters from the soil map of Africa (250m), the land use map GLC30, the depth to bedrock map, the digital elevation model and observed flow data. The estimation approach is applied to the Ouergha basin (Sebou, Morocco). The proposed approach’s interest is to feed the HEC-HMS hydrological model with initial values of parameters close to the study area reality instead of using random parameters.

Highlights

Hydrological models are essential tools for water resources management studies
In their study, [11]considered that the soil depth equals the six layers' total depth composing the soil in the African soil grid 250m data because this map was not yet available
This work attends to use an innovative approach to determine the initial values of the HEC-HMS model parameters

Summary

Introduction

Hydrological models are essential tools for water resources management studies. Hydrological models have widely been used for assessing flood risks[1], [2], simulating climate change impact on water resources[3], [4], quantifying land use-land cover impacts on hydrology[5], [6], and estimating erosion[7], [8]. The lack concerns hydroclimatic, soil and land use data. The soil and land cover data are essential to simulate interception, transpiration and surface runoff processes. The goal of a good evaluation of the initial values of hydrological model parameters is to avoid convergence during the model calibration to mathematical solutions having no link with the physical characteristics of the basin. Ahbari et al proposed a detailed methodology to calculate initial values of the HMS model formalisms mainly intended for African basins where quality, accessibility and availability of data is a real problem[11]. The approach proposed is based on free and accessible soil and land use data. This work aims to establish a set of initial values following the proposed estimation approach in another different context of soil, topography and land cover. Ouergha basin is a vital basin that regulates the third of surface water resources and supplies the country's largest dam[12]

Study area

Data required and maps elaborated

Estimation approach

Discussion and Conclusion