Confined Aquifer Sustainability Study

The Colorado Division of Water Resources is issuing a Notice of Proposed Sole Source for a Confined Aquifer Sustainability Study (NPSS1 PEAA 2027*0051) with a challenge submission deadline of September 15, 2026. This is a sole-source procurement; HRS Water Consultants is the proposed awardee based on extensive regional experience with Division 3's aquifer systems and expertise in San Luis Valley hydrogeology specific to the Rio Grande Basin.

The scope requires investigation of confined aquifer system inflows and outflows; estimation of historical water levels and artesian pressures from 1978 through 2000; and analysis of relationships between groundwater withdrawals, climatic conditions, and system water levels. The consulting firm must be experienced with the Rio Grande Decision Support System (RGDSS). Work comprises four tasks: Task 1 investigates inflows, outflows, and effects of pumping and climate; Task 2 evaluates five potential estimation methodologies (Thiessen Polygon Composite Head, Linear Interpolation using Reference Wells, Model Infill, Water Budget Approach, and Historic Consumption); Task 3 recommends preferred methodologies; and Task 4 documents findings in a comprehensive report. Key deliverables are study completion by September 30, 2028, a draft report by October 31, 2028, and a final report by March 15, 2029. The final deliverables will inform the State Engineer's determinations on sustainable water-supply management and potential amendments to existing groundwater withdrawal rules.

The budgeted amount is approximately $249,950. A Purchase Order is anticipated in August 2027, pending available funding. The sole-source procurement end date is June 30, 2029. Entities wishing to challenge the sole-source determination or demonstrate comparable capabilities must submit a one-page cover letter to Jeanette Stroud at the Department of Natural Resources Purchasing Office with the solicitation number in the subject line.