Challenge

Leavens Ranches sought to replace an existing irrigation well with a new, deeper well because the irrigation water in the existing well was not reliable. Nearby agricultural properties had wells completed to depths of 800-1,000 feet. The client needed to ascertain the feasibility of drilling a deeper well to improve the reliability of irrigation water and groundwater quality.

Solutions

GLA was contracted in to provide hydrogeological support services for the new well. Our team began by investigating groundwater in neighboring wells in an approximately one-mile radius, tabulating data from well completion reports, groundwater levels, and water quality sampling on the wells. We summarized this data in a Hydrogeologic Tech Memo that included recommendations for the preliminary design of the replacement well.

GLA’s recommendation was a pump bowl depth installation of 250 to 300 feet below ground surface. We also included a recommendation to assist in lower dissolved total solids concentration in the pumped water by conducting groundwater flow profiling and discrete depth water quality sampling in the new well to determine which zone(s) within the screened interval are yielding the highest concentrations.

The client used our recommendations for the preliminary design in the bid packet to prospective well drilling contractors. GLA also assisted with the bidding process by developing specifications and assisting in selection of the drilling contractor. Once the contractor was selected, GLA provided construction oversight, including direction of well construction, development, and aquifer testing. Upon completion of the construction, GLA designed and supervised an aquifer testing program that included step and constant rate pumping tests, all included in our final summary well installation report.

Results

The well was successfully completed in a deeper aquifer, meeting all of the client’s needs. Our design recommendation resulted in a well that yielded over 150% of the target production capacity and maximum well extraction rates of 250% of the target design. The water quality has also proven to be much higher than the original well.