Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Estimating components of groundwater balance through geospatial techniques in Hard Rock aquifer of semiarid regions

Auteur : Mehnaz Rashid

Université de soutenance : Osmania University (India)

Grade : Doctor of Philosophy (PhD) 2014

Résumé partiel
Components of groundwater balance (GWB) are highly variable in space and time. Inaccurate or partial estimation of these components not only lead to uncertainties in water budgeting but also creates groundwater planning and management issues. To address the challenges of aquifer prospecting vis-à-vis sustainable management, efficient and precise quantitative estimation of GWB components is essential. Conventionally, GWB components are estimated using point data measurements, involving larger uncertainties due to heterogeneous landscape, hydroclimate and lithology. It is indispensable to understand the mechanisms and driving forces behind major components of the groundwater balance to allow reliable estimation of the resource. This endeavor proposes a new methodology for computing various vital components of groundwater balance using geo-spatial techniques which provides high data density. Water resources are limited in semiarid hard rock terrains, thereby severely constraining the regional groundwater, for irrigation and domestic use. The hydrological regime in these areas is extreme and highly variable, due to heterogeneous landscape and rainfall pattern. Largely covered by hard rock terrains and semiarid climatic conditions, southern India is worst-hit by water scarcity issues, due to enormous groundwater abstraction for agricultural activities. The amount of recharge and discharge directly affects aquifer storage. Therefore it is a prerequisite to draft precise and appropriate estimation techniques. Remote sensing in combination with GIS based modeling offers comprehensive spatial information to estimate major GWB components in space and time with higher accuracy. The main objective of the present study was to estimate the major components of GWB in Gajwel watershed, located in Medak district of Andhra Pradesh, India. The climate of the area is semiarid with hard rock granitic terrain. The study establishes two methodologies viz., estimation of major groundwater balance components and groundwater prospecting in the study area.

Mots clés : Groundwater balance ; Remote sensing ; GIS ; Hard rock ; Semiarid ; Evapotranspiration ; Runoff ; Recharge ; SEBAL ; TRMM. 

Présentation et version intégrale