Horizontal Collection Well No. 119 is part of the ongoing expansion of South Adams County Water and Sanitation District’s (SACWSD) separate irrigation supply system serving the north range area of the district.

Muller served as the Owner’s representative during the project formulation phase and the Construction Manager/General Contractor (CM/GC) design phase of the $1.8M well. Muller later provided design and bid phase services for the pump station that was supported and cantilevered off the top of the well.

Muller also provided construction phase services for this $2.1M pump station project. The pump station was designed to house four, 350 horsepower pumps, each capable of pumping one third of the total design flow, with one of the four serving as backup. The firm capacity of the pump station is 9,000 gpm (13 MGD) and is the largest alluvial production well in Colorado.

Under a separate contract, SACWSD retained Muller to provide design and bid phase services for the initial 1.6-mile $3.6M phase of a 7-mile, 30-in/36-in transmission line that will ultimately extend from the Well No. 119 site near 96th Avenue at the South Platte River, to the district’s Landmark Pump Station and Reservoir near 104th Avenue and Landmark Drive in the heart of the district’s northern growth area.

Upon development and pump testing of the completed collector well, the firm yield was determined to be just under 9,000 gpm (13.0 mgd), roughly double the original projection range. As a result, this well now boasts the highest documented municipal well yield in the state. Surprisingly, the yield from this single well exceeds the combined total of the 11 existing conventional wells that currently supply the district’s irrigation system by over 40%, and represents more than 25% of the ultimate max-day flow projected at full build-out for the entire 230,000 resident service area. In a manner that has truly exceeded expectations, this well has become the undisputed cornerstone of supply for Colorado’s largest separate municipal irrigation system.

Using the average yield of the district’s 11 existing vertical irrigation wells, the district anticipates spending approximately $1,660/gpm to develop future conventional wells that will be needed. In comparison, Colorado’s first horizontal collector well comes in at a unit cost of $520/gpm, less than one third the projected cost for conventional well development.