AN INVENTORY OF ARTIFICIAL RECHARGE IN THE STATE OF COLORADO

As part of a statewide assessment study of artificial recharge (AR) potential in Colorado, the Colorado Geological Survey (CGS) inventoried existing AR operations in the state. Framed by a diverse hydrogeological environment, Colorado's groundwater resources are being increasingly recognized by planners and policymakers as filling a critical role in the state's water supply, particularly during periods of drought. Storage of water in the state's aquifers can be a viable alternative to building new surface storage facilities and the assessment study sought to identify how and where AR could best be implemented throughout the state. However, the first step in charting future development of AR is mapping out what is already in place. This inventory identified 19 active operations in many different geologic settings that currently meet a number of objectives and use a variety of technologies. AR is being utilized to meet legal requirements of decreed augmentation plans, provide seasonal storage throughout irrigation seasons, provide long term storage for municipal and industrial uses, and to regulate water quality. To meet these objectives AR is being implemented through surface infiltration, direct injection through aquifer storage and recovery wells, and utilization of abandoned coal mines. AR is being implemented in unconfined alluvial and basin fill aquifers as well as semi-consolidated sedimentary aquifers.