Instructional

Abstract

There are sparse hydrogeological data and insufficient hydrogeological knowledge in many areas of the world reliant ongroundwater. Nicaragua’s Pacific coast is one such region that is also experiencing water scarcity resulting from increasingdemand on groundwater resources and climate change. The primary source of water in the region is the aquifer system associatedwith the Brito Formation, which is a marine sedimentary stratum of mostly sandstone that blankets 75 km of coastline insouthwest Nicaragua. This study focused on the Tola municipality with the objective to advance a conceptual understandingof the hydrogeology and to support sustainable water development. Results demonstrate a heterogeneous aquifer system withregional flow characteristics and other factors that influence groundwater availability and water quality. Primary porosity is low,and secondary porosity is the primary mechanism of aquifer storage and is influenced by geological structure and diagenesisprocesses. Groundwater recharge is spatially and temporally heterogeneous and direct recharge is low. Infiltration of streamflowand runoff, especially early in the rainy season, is thought to be a large component of groundwater recharge. Climate, flow andrecharge dynamics, and low storage capacity make the Brito Formation a sensitive resource and vulnerable to drought, increasedabstraction, and climate change. This assessment provides data and insights useful for informing future studies and investmentswithin the region and may be applicable in other Central American and Caribbean nations with coastal sandstone aquifers.