Consumptive water use for agriculture, drinking water, industrial processing, and hydropower production make up the majority of diversions in Colorado. The water withdrawn from river and groundwater systems make our society possible, and Colorado’s water rights allocation and administration system are based upon a philosophy of maximizing beneficial use. Since river flow is the “master variable” driving river health, understanding current and future consumptive water use is fundamental to both an SMP and an IWMP.
Surface water diversions to support irrigated crop production and hay-pasture for livestock account for the single largest water use in Colorado. Those completing SMPs in areas with agricultural water use may want to assess:
The stream functions and community benefits supported by irrigation, including near-stream groundwater recharge, maintenance of open space and wildlife habitat, and local economics
Irrigation needs and gaps under current and future climate scenarios
River and groundwater systems provide drinking water for most, if not all, Colorado municipalities. Municipal water providers must meet certain regulatory obligations such as drinking water and wastewater treatment standards. Municipal providers must also pay attention to other variables such as the quality of water upstream of their drinking water intakes, the quantity of water downstream of their intakes, population growth, hydrologic changes brought about by climate change, and recreational use of reservoirs and river corridors. SMPs in areas with municipal water use may want to assess:
Municipal water conservation efforts
Forecasted population growth
Water demand forecasts and gaps under current and future climate scenarios
Integrated Resource Plans that identify future infrastructure needs and conditional water rights
Many industrial water uses are accounted for through a municipal supplier; however, there are industrial water users with their own water rights. Notably, coal production, thermoelectric power generation, and oil and gas extraction are significant water users and important contributors to the vitality of some resource extraction-based economies. SMPs in areas with industrial water use may want to assess:
Water demand forecasts and gaps under current and future climate scenarios
Plant lifespans and required resource plans to evaluate future electric demand and the generation resources best suited to meet demand
Location and amount of conditional water rights
Community benefits supported by industrial processing, including local economics
Limited hydropower production exists in Colorado. While not widespread, it plays a fundamental role in shepherding water through stream networks—providing water that contributes to stream health and recreational use on stream segments upstream and downstream of the point of use, as well as consumptive uses downstream with junior water rights. SMPs in areas with hydropower production may want to assess:
Benefits or impacts to other stream functions and community benefits including fisheries, recreational use and meeting junior water rights downstream
Potential Data Sources
Diversion infrastructure assessments
Municipal water conservation plans
Municipal and/or County land use plans
Municipal water supply or integrated resource plans
Analysis and Technical Update to Colorado’s Water Plan
Drinking Water Consumer Confidence Reports
Electric Resource Plans
Diversion Infrastructure Assessments
Conducting an assessment of diversion infrastructure in areas with substantial agricultural irrigation can identify opportunities to improve agricultural producers’ operations, as well as opportunities to improve river function variables such as fishery quality, bank stability, or hydrology. These assessments can be simple enough to be completed by trained volunteers, or complex enough to require a licensed engineer. Partnering with a fisheries biologist can help to assess fish passage impediments and opportunities. Infrastructure assessments must be undertaken only with the full cooperation of diversion structure owners, and illustrate clear benefits to them for their participation.
The October 2020 Peer Workshop provides an overview of various approaches and goals for diversion assessments, and some are explained here. Trout Unlimited released a Water Diversion Selection Tool in November 2022 to help resource professionals identify a suite of site compatible diversion mechanisms and the ecological and logistical tradeoffs of each.
Rio Grande, Conejos River, and Saguache Creek Stream Management Plans
Rio Grande Headwaters Restoration Project staff completed an inventory and functional assessment of in-stream diversion infrastructure by visiting each structure and collecting photos to document current conditions and highlights repairs and improvements needed. The inventories included ditch headgates, flumes (or other measurement devices), diversion dams, and nearby channel conditions affecting the structure. Each structure’s current condition was rated using an A-F scale based on the structure’s ability to divert water efficiently, its impact on channel conditions, and its impact on recreational uses, especially boating. Additional details about the Rio Grande’s diversion infrastructure inventory can be found near the bottom of their SMP website.
North Fork of the Gunnison
As part of its Phase 1 SMP, the North Fork Water Conservancy District hired J-U-B Engineers to conduct interviews with major agricultural diverters and perform a river infrastructure assessment. The assessment included:
- Apparent deficiencies in structural integrity and diversion functionality
- Apparent deficiencies in diverting a wide range of flows
- Apparent deficiencies that may negatively affect river function
- Apparent deficiencies that may negatively affect recreational use of the river
- Preliminary estimate of construction costs to address any deficiencies
The Final Report includes a prioritized list of potential diversion improvement projects resulting from their infrastructure assessment.
The Bookcliff, South Side, and Mount Sopris Conservation Districts (working alongside the Middle Colorado Watershed Council) are conducting a consumptive use needs assessment for the IWMP. The assessment’s objectives are to determine the water supply necessary to meet the needs of consumptive water users and to identify projects that can be completed to improve water conveyance and application efficiencies to meet consumptive use demands utilizing conservation practices. The main objective is to gather information on current consumptive use practices and offer opportunities to safeguard the ability of agriculture to continue producing food and fiber in a healthy and sustainable landscape.
Yampa Basin Integrated Water Management Plan
The IWMP includes a voluntary irrigation infrastructure assessment. The assessment’s goal is to identify locations where infrastructure improvement could provide multiple benefits to the Yampa River and its users. Beneficiaries of improvement might include agricultural producers, recreational boaters, and fish, to name a few. The primary objectives of the Assessment are to:
- Identify priority areas for infrastructure evaluations within each segment;
- Complete 40-50 onsite, infrastructure evaluations; and
- Document and prioritize opportunities for infrastructure improvement.
The RFP includes more detail about planned tasks.
Municipal Water Supply Projects
Municipal providers must provide clean, ample water for the current and future populations of their service areas. This includes drinking water, wastewater, storm water, and recreation projects. SMPs can be used to understand how this array of city services can impact river health. They can also inform decisions about the location and size of new or expanded infrastructure such as reservoirs, pipelines, or diversions.
The Poudre River Health Assessment
The purpose of the 2017 State of the Poudre River is to describe the current health of the Cache la Poudre River through Fort Collins. Population growth and new water supply development upstream are placing additional pressure on the river ecosystem. The river health assessment gives the City of Fort Collins a benchmark against which to track impacts due to future changes in land use and flow. It created a centralized and coordinated approach to measure the collective impact of the city’s efforts on the overall health of the river.
The Eagle Community Water Program
The Eagle River Community Water Plan will develop proactive water management recommendations that anticipate changes to hydrology due to:
- Population growth and increasing municipal demand for water in Eagle County
- Climate change
- Projects related to the Eagle River MOU (ERMOU), an intergovernmental agreement for developing West Slope and East Slope municipal water supplies in the upper Eagle River watershed.
To accomplish No. 3, the plan will analyze Eagle River flow regimes under existing conditions and forecast it with maximum in-basin demand projections and with ERMOU project scenarios. The goal is to identify the potential vulnerability to stream health and community benefits due to changes in flow that may result from municipal demand increases.