Greeley's Water Future: Terry Ranch Project

Greeley is purchasing the water rights and water storage under the Terry Bison Ranch, but is not purchasing the surface land.  The land is currently used for grazing bison. 

Greeley will use ion exchange treatment.  Ion exchange is essentially a scaled-up water softener - water runs through tanks containing media that absorb and remove uranium.  Ion exchange media can be specified to remove a wide variety of contaminants.  Ion exchange treatment is a common and proven technology that is used across the country.  Greeley operated a pilot treatment plant on the Terry Ranch for 30-days and proved the uranium will be removed to below detection.  The ion exchange system will be designed with full redundancy.  

Water from Terry Ranch will flow by gravity from the ranch to Greeley.  In fact, we will need two pressure reduction valves (PRVs) along the way to reduce pressure so as not to damage the pipeline.  Depending on future economics, we may replace the PRVs with hydropower generators and will design the PRV stations to allow for future adaption of hydropower equipment. 

The environmental impact of Terry Ranch is low relative to all of the other water supply projects Greeley has evaluated to date.  Nearly all infrastructure for Terry Ranch will be buried below ground.  The exceptions are small (“doghouse”) buildings at each well, the treatment plant (which will be located on an area formerly mined for gravel), and two pump/pressure reducing stations.  We have completed an environmental assessment for wetlands, threatened and endangered species, and archeological resources, and have determined construction can avoid most if not all sensitive resources.  We have design the pipelines to follow roads, power lines, and railroad tracks to use previous disturbed areas.  Additional field verification will be needed at the actual time of construction.  The Terry Ranch Project will require more pumping and power usage than our existing, conventional treatment plants.  Consequently, there will be more GHG emissions than our current treatment plants.  There is a potential to add hydropower generation in the pipeline from Terry Ranch to our existing pipeline north of Windsor.

We tested for glyphosate in the Terry Ranch groundwater from six wells and 13 sampling events. All tests were below detection.

Over the past six months Greeley conducted an extensive evaluation of environmental conditions on the ranch and did not discover any significant sources of potential contamination.  There is no oil and gas development on the ranch and our evaluation finds that the risk of future development of oil and gas is low.  Also, groundwater Greeley would be buying is generally very deep underground and isolated from the surface, reducing the risk of surface contamination.  

Currently, there is no oil and gas (O&G) development on Terry Ranch. Three exploratory wells we drilled in the past, but were plugged and abandoned consistent with Colorado Oil and Gas Conservation Commission (COGCC) regulations, which require the placement of multiple cement plugs in the well bore. The lack of economic development of O&G reserves at Terry Ranch is an indicator unsuitable hydrocarbon reserves on or near the property.

Were O&G development to occur in the future, the COGCC has various authorities to protect groundwater. The Upper Laramie Aquifer is formally recognized by the COGCC as a drinking water supply, and as such, operators are required to install casings that extend through the aquifer. Reports of well casing failures leading to groundwater contamination are rare. It should be noted that O&G development, if it occurs, would take place many thousands of feet below the Upper Laramie Aquifer. Between the potential hydrocarbon formations and the Upper Laramie Aquifer are several thick layers of shale and coal that act as barriers to O&G migration. O&G development has been ongoing beneath the Laramie-Fox Hills Aquifer for more than 150 years, and the Laramie-Fox Hills Aquifer provides water to several Denver Metro communities. To our knowledge, there have been no reports of contamination of the Laramie-Fox Hills Aquifer by O&G production operations.

The Greeley Water & Sewer Board is tasked to develop water supplies to meet a growing population.  We forecast future water needs using population projections of the Colorado State Demographer.  Those projections anticipate Greeley doubling in population over the coming decades.  Although Greeley has adequate water supplies to meet our needs today, additional supplies are needed to meet our growing population.  Water supply and storage projects, such as the Terry Ranch Project, are needed to fulfil our obligation to our citizens to provide a safe and reliable source of water now and in the future. 

City staff has sought to proactively engage the Greeley community and seek public input on the Terry Ranch Project over the last eight months.  Staff consistently aimed to be transparent and effective communicators on this project.  The project was first presented at Greeley Water & Sewer Board meeting in June 2020, and since that time there have been three City Council meetings dedicated to the project in addition to monthly Water & Sewer Board meetings in which citizen input is sought.   Community Open Houses were held on December 2, 2010 and February 10, 2021 wherein the city’s team answered questions from the public.  Over the last several months, city staff and the Water & Sewer Board Chairman have presented to over 20 community organizations, service clubs, and city Boards and Commissions.  There has been significant coverage on the project in print and radio, and the city has advertised the project on social media for several months.

The Centennial Mine proposed west of Nunn, CO is in a different, deeper, and isolated geologic formation (Fox Hills Sandstone) than the Terry Ranch aquifer (Upper Laramie Aquifer).  The location of proposed drilling at the Centennial mine is down-gradient of Terry Ranch, meaning that should, in the very unlikely event, contamination occur along the conduit through the impermeable layer between the Fox Hills Sandstone and Upper Laramie Aquifer, contamination would travel in the opposite direction from the Terry Ranch wellfield.