Understanding Water Table Fluctuations in a Karstic Semiarid Mediterranean Aquifer Through Numerical Modeling: The Case of Almudaina-Segaria Aquifer

Abstract

The exploitation of underground water has an important role in the province of Alicante, Southeast Spain, where it is mostly used for agriculture and the supply of populations. The Almudaina-Segaria hydrogeological domain, in northern Alicante, constitutes the water supply for La Vall d’Ebo, Planes and Gorga villages. This domain includes the Almudaina-Segaria system, a 167 km² carbonated karstic aquifer with 700 m of permeable thickness made of limestones, dolomites, and marls. In this project the aquifer’s water flow was modeled using MODFLOW and ModelMuse for the interval 1980–2019, aiming to understand its dynamics. The water input is provided by the infiltration of precipitation (approximately 730 mm and 68 hm³ of annual precipitation and recharge, respectively), while the output is conducted through direct pumping (up to 2.31 hm³/yr), natural drainage to the Vergel and Pego aquifers and, mainly, discharge through the Finca Rincón del Rosario drainage and the Racons River (54.44 hm³/yr). The groundwater flow occurs in a SW–NE direction toward the discharge zone. The aquifer modeling is a useful tool for an appropriate management of water resources in the north of the Alicante province, given its importance as a main support for the populations and activities that take place there.