L’utilisation des bilans d’eau dans les zones humides pour relier les processus hydrogéologiques aux conséquences écologiques

Abstract

A methodology for modelling wetland water levels using the water balance approach was developed for Pulborough Brooks Site of Special Scientific Interest in West Sussex, in the UK. The methodology was applied to assess potential groundwater abstraction impacts on communities and species of ecological importance in the wetland. The modelling methodology links regional hydrogeological processes to wetland hydrology and ecology that is typically influenced by processes that take place at a more reduced spatial scale. To assess impacts, it is necessary to understand the hydrological sources of water that are affected by abstraction as well as to consider how the magnitude of these processes relates to other processes that influence wetland water levels. Water levels are commonly the most important factor determining the presence or absence of species or communities in a wetland and the model predicts wetland water levels and assesses how suitable these water levels are for species of ecological significance. Model results show that typical historic rates of abstraction have not resulted in an adverse effect on the integrity of the Pulborough Brooks relative to a ‘natural’ (no abstraction) scenario.