AGRICULTURAL ACTIVITY IN MANY REGIONS IS LIMITED BY THE AVAILABILITY AND QUALITY OF FRESH WATER. GROUNDWATER PUMPED FROM WELLS IS PARTICULARLY IMPORTANT IN MANY PARTS OF THE UNITED STATES. IN SOME AREAS, MUCH OR MOST AGRICULTURAL ACTIVITY DEPENDS ON GROUNDWATER. UNFORTUNATELY, GROUNDWATER SUPPLIES ARE BEING DEPLETED IN MANY PLACES BECAUSE OF INCREASED USE, CHANGING LAND USE, AND SHIFTS IN CLIMATE. THE LAST TWO OF THESE FACTORS TEND TO LIMIT THE INFLOW OF SURFACE WATER INTO AQUIFERS (SUBSURFACE FORMATIONS THAT CAN STORE AND TRANSMIT WATER IN USABLE QUANTITIES), ALSO KNOWN AS "RECHARGE." GROUNDWATER DEPLETION ALSO LEADS TO A LOWERING OF WATER QUALITY, AS SALTS, NUTRIENTS, AND OTHER CONTAMINANTS CAN INCREASE OVERTIME. MANAGED RECHARGE IS A SET OF METHODS AND TOOLS THAT CAN BE USED TO INCREASE THE SUPPLY AND QUALITY OF GROUNDWATER. THUS THERE IS A NEED TO IMPROVE STRATEGIES TO INCREASE GROUNDWATER RECHARGE, AND TO IMPROVE WATER QUALITY IN THE PROCESS. THIS PROJECT SEEKS TO ENHANCE GROUNDWATER SUPPLIES AND QUALITY BY HELPING WITH MANAGED RECHARGE USING STORMWATER RUNOFF, EXCESS SURFACE FLOWS THAT OCCUR DURING AND AFTER INTENSE RAIN EVENTS. WE ARE PARTICULARLY INTERESTED IN DETERMINING HOW BEST TO REDUCE THE CONTENT OF "NITRATE," A COMMON CONTAMINANT IN RUNOFF IN AGRICULTURALLY ACTIVE REGIONS, DURING MANAGED RECHARGE. THE PRIMARY APPROACH WE WILL USE IS THE ADDITION OF A CARBON SOURCE TO SHALLOW SOIL WHERE WATER FLOWS INTO UNDERLYING AQUIFERS, FOR EXAMPLE WOOD CHIPS, MULCH, ALFALFA, AND/OR ALMOND SHELLS. THESE SOIL AMENDMENTS SHOULD HELP TO STIMULATE THE ACTIVITY OF NATURAL MICROBES THAT LIVE IN THE SOIL AND CAN HELP TO REMOVE NITRATE. WE ARE ALSO EXPLORING HOW REMOVAL OF NITRATE MIGHT BE ACCOMPANIED BY HIGHER CONCENTRATIONS OF METALS IN INFILTRATING WATER. THIS WILL BE DONE WITH A MIXTURE OF FIELD AND LABORATORY EXPERIMENTS, INCLUDING WORK AT AN ACTIVE MANAGED RECHARGE SITE USING STORMWATER. IN THE FIELD REGION, THE RESEARCH TEAM IS HELPING TO RUN A PROGRAM THAT PAYS PUMPING-FEE REBATES TO REGIONAL STAKEHOLDERS WHO HOST RECHARGE PROJECTS ON THEIR PROPERTY. THIS NOVEL INCENTIVE PROGRAM MAY HELP TO ENCOURAGE OTHERS TO HELP BUILD AND OPERATE RECHARGE SYSTEMS, FOR THE BENEFIT OF GROUNDWATER SUPPLY AND QUALITY. THIS PROJECT IS A COLLABORATION BETWEEN UNIVERSITY PERSONNEL, RESOURCE CONSERVATION DISTRICT STAFF, A REGIONAL WATER AGENCY, AND AGRICULTURAL STAKEHOLDERS.