Integrating ground and surface water management

The water in our rivers is often affected by the water in the ground, and the water in the ground can be enhanced by the water that flows across and infiltrates into the land surface. In other words, surface water recharges groundwater and groundwater can discharge into surface water bodies. The extent of this relationship depends on the type of hydrologic connection which in turn depends on geology, geography, topography, and other factors. Groundwater discharges to rivers sustains their “base flow,” which is the water flowing in rivers in between rain storms or snowmelt periods. This base flow is critically important to river health during drier times of the year or during periods of drought.

Given these interconnections between surface water and groundwater, when surface water is of poor quality or quantity, it can impair the quality or quantity of nearby groundwater. And in many instances the reverse is true as well – when groundwater is polluted, it can contaminate surface flows and when it is depleted, it will not be able to serve as a significant source of base flows.

Like other water resources, state law generally matters most. Find out how your state regulates groundwater, whether it views groundwater and surface water as a single resource to be managed together or not, and whether there are threats to groundwater security and quality. Consider whether conjunctive use or management (scenarios where water is “banked” or stored in groundwater basins and then extracted for later use) holds promise for restoring or protecting water for your river during dry periods and whether appetite exists for integrated water resource management approaches.

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