THE ENLARGEMENT OF MILTON SEAMAN RESERVOIR

John G. Gauthiere, P.E./Greeley Tribune Guest Commentary 9/30/2020

The City of Greeley (COG) is in jeopardy of losing the opportunity to acquire new high-quality water supply and drought protection through the enlargement of Milton Seaman Reservoir (MSR).  The Greeley Water and Sewer Department staff has paused progress on the U S Army Corps of Engineers (USACE) permitting process that would allow the enlargement of MSR from its existing 5,000 acre-feet to  53,000 acre-feet.

The USACE requires alternatives to be considered  before a permit is issued for the enlargement of MSR, but a pause in the permitting process is not required while the City of Greeley considers alternatives to supply water to Greeley. 

The alternative the COG is looking at is a major departure in Greeley’s historic and successful surface water acquisition program.  The COG Water and Sewer Board has entered into an extremely complicated agreement with Wingfoot, LLC to purchase credits in an aquifer at Terry Ranch near the Wyoming border.  This agreement allows a seven-month diligence period which ends in January 2021, at which time the Greeley City Council will vote to approve or disapprove the agreement.

Greeley has been successfully developing and acquiring surface water supplies since 1907.  This surface water, which recently won a national award for the best tasting drinking water in the nation, is brought to us courtesy of snow melt in our beautiful Rocky Mountains.  It enters the Poudre River and flows to  five high mountain reservoirs and MSR where it is stored, or continues flowing to the Bellvue Water Treatment Plant where it is treated and flows by gravity to Greeley and other neighboring communities like Evans, Windsor and Milliken.

The Terry Ranch aquifer alternative is particularly complicated.  Ground water contains a variety of contaminants.  Some of these can be uranium, arsenic, and manganese.  As you may recall, the citizens of Nunn, 20 miles north of Greeley, successfully fought to prevent a uranium mine near their town.  In fact, some of the test wells drilled on the proposed future ground water source for Greeley showed the presence of abundant uranium.  The presence of uranium and various other contaminants will complicate the water treatment process to an astronomical degree and be many times more expensive.

The danger in stopping the permitting process for MSR is that it shows a lack of diligence in perfecting the conditional enlargement decree the COG has on MSR.  This means that the COG is not making progress in putting to beneficial use the conditional decree that it has.  The State of Colorado will interpret this as an abandonment of the conditional decree of 10,000 acre-feet additional storage in MSR. 

The enlargement of MSR to 53,000 acre-feet is a very feasible project.  Recent construction cost estimates for MSR enlargement indicate that the cost per acre-foot of water storage is around $2,000 per acre-foot.  This is very economical compared to the Northern Colorado Water Conservancy District’s (NCWCD) excellent ongoing Chimney Hollow Dam Project which is estimated to cost $4,440 per acre-foot of storage.

The enlargement of MSR would also provide drought storage for other water owned by the COG.  MSR could provide about two years of storage for Greeley water customers during a prolonged drought.

NCWCD’s NISP Project and Fort Collins’ Halligan Reservoir Enlargement Project are in the last stages of their permitting process.  Greeley is lagging far behind.  It is in the best interests of all Greeley water customers for the COG Water Department staff to restart the permitting process and make a diligent effort to achieve this goal.