Artificial Recharge in the South Platte Basin Innovations and Challenges for the 21st Century

Artificial recharge in the Lower South Platte Basin started in the 1970s in Logan County near Sterling, Colorado. The South Platte Ditch was the first ditch company to develop and utilize the re-regulated flow accretions to the South Platte River resulting from the artificial recharge into an off ditch recharge basin. Since that time, artificial recharge in the South Platte Basin has been used to re-regulate excess river flows and generate river accretions during times of flow shortages. Numerous ditch and reservoir companies, municipalities, water districts and private individuals average over 4.94 x 10⁷ m³ (40,000 acre-feet) of annual diversions to recharge resulting in annual river accretions of 1.73 x 10⁷ m³ (14,000 acre-feet). Historically, artificial recharge accretions have been used to replace depletions caused by alluvial large capacity irrigation wells. The basin recession response to alluvial withdrawals and artificial recharge are an important component in the overall management of the basin's water resource. Water quality of the recharge source and receiving alluvial resource is becoming more of a concern with regard to the potential of groundwater quality impairment. Specifically, nitrate loading of the alluvial resource and the attenuation of nitrates through the alluvial aquifer has been investigated by several state and federal agencies.