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

• Groundwater recharge is typically treated as a beneficial ecosystem service.
• Case study of watershed shows that recharge can be both beneficial and detrimental.
• Recharge increases water supply and can positively impact crop production.
• However, excess recharge can damage crops and increase runoff and flood risk.
• Recharge should be viewed as a system input leading to positive & negative outcomes.

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.