As water supply becomes increasingly unreliable, state and local governments are forced to stretch their limited resources to meet various and competing needs. But water managers often only have the tools to consider urban, industrial, energy and agricultural uses. Ecosystem health is a crucial missing element.

Two female wild salmon are swimming past an observation window as they traverse a salmon ladder at Torrent River. Photo: Gail Shotlander / Getty Images.

Water diversions can decimate aquatic habitat by draining wetlands, hindering fish migration, and increasing saltwater intrusion. Climate change intensifies the impacts with warming waters, ocean acidification, and extreme weather. Addressing these effects – and choosing sustainable policy options – means integrating ecosystem needs into water management.

The Stockholm Environment Institute has developed a platform that allows users to model the effect of various management options on the availability of habitat and the viability of aquatic species. This fact sheet details how SEI uses its Water Evaluation And Planning (WEAP) system to integrate hydroecological processes within a water operations model.