Is groundwater recharge always serving us well? Water supply provisioning, crop production, and flood attenuation in conflict in Wisconsin, USA

Abstract

Ecosystem service mapping can provide an avenue for making effective land management decisions in a holistic way. However, mapped quantities do not always appropriately represent the ecosystem services that are used by humans. We highlight this issue with a case study of groundwater recharge, water supply, flooding, and agricultural production in an urbanizing agricultural watershed in southern Wisconsin, USA. Groundwater recharge is typically treated as a beneficial ecosystem service or service indicator whose value to humans monotonically increases with the amount of recharge. While appropriate from a water supply perspective, this relationship breaks down when excess groundwater recharge leads to flooding and crop damage. We suggest moving beyond groundwater recharge as a stand-alone ecosystem service, and instead propose that observations and biophysical models should be used to quantify the final service humans receive from groundwater (e.g. reliability of water supply from a municipal well). Integration of such derived, point-based metrics with other ecosystem services that are more easily represented at the landscape scale remains a challenge for regional ecosystem service inventories and analyses.