Statewide Water Supply Initiative gets update in 2018

VALLEY — Colorado entered the new millennium on the heels of the largest population growth in the state’s history, but this growth coincided with a relatively wet cycle. All this changed at the end of the 1990s and the first years of the new century saw the onset of a severe drought. In some areas of the state 2002 was the driest year in recorded history.

This was the impetus for the 2003 Colorado General Assembly to authorize the Colorado Water Conservation Board (CWCB) to implement the first Statewide Water Supply Initiative (SWSI). SWSI was an unprecedented effort for the CWCB. Never before had Colorado developed such a comprehensive picture of its water future and never had such a broad spectrum of water users been assembled to look at the state’s water supply future.

This group of stakeholders included: farmers, ranchers, municipalities, industrial users, recreationalists, and environmentalists. Together they gathered and shared data and then worked with the CWCB to compile the findings. SWSI identified Colorado’s current and future water needs and examined a variety of approaches to meet those needs. SWSI culminated in 2004 with the first version SWSI 1.0.

However, by design, SWSI was an “initiative” not a “report.” CWCB intended for SWSI to continue and be the basis for Colorado’s water supply planning process. In 2006, the report was supplemented by SWSI 2.0 which added technical work on water conservation, alternative agricultural water transfers, environmental needs, and options and strategies for meeting the municipal water supply “gap,” the difference in what municipalities had and what was needed.

The SWSI process implemented a collaborative approach to water supply planning by establishing “basin roundtables” – diverse groups of people who provide input on water issues. The basin roundtables established a grassroots effort for education and collaboration. These efforts were institutionalized in the Colorado Water for the 21st Century Act of 2005. The Act created nine Basin Roundtables – one for each of the state’s major river basins and one for the Denver Metro area. The Act charged the Basin Roundtables to develop consumptive and non-consumptive needs assessments and to propose projects and methods that would meet those needs.

In 2010, CWCB updated its analysis of the state’s water supply needs with SWSI 2010. SWSI 2010 relied on the Basin Roundtables need assessments and was used to inform local and regional water planning efforts. SWSI 2010 found that Colorado faces a shortage of water for meeting the state’s consumptive and non-consumptive water needs and surmised that to meet Colorado’s water needs, a mix of local water projects and processes, conservation, reuse, agricultural transfers, and the development of new water supplies should be pursued concurrently. SWSI 2010 warned, that if Colorado did not implement a mix of solutions, but relied on the status quo, Colorado would lose an unacceptable amount of irrigated agricultural.

SWSI 2010 included other key findings:

Agricultural Demands — Each basin faces continued shortages associated with existing agricultural demands. There are pressures to keep agriculture economically viable; however, the state could also face a significant decline in irrigated acres by 2050 due to urbanization, water transfers, and market pressures.

Municipal Demands— Colorado’s population is projected to nearly double to between 8.6 and 10 million people by 2050. The Front Range of Colorado will continue to be the most populous place in Colorado with over 80 percent of the state’s population, but the West Slope of Colorado will grow at the fastest rate of any area in Colorado. Colorado will need between 600,000 and 1 million acre-feet/year of additional municipal and industrial water by 2050. This amounts to an 18 percent decrease in the amount of water each person uses. Yet the report recognized that it was difficult to quantify conservation savings and that these amounts at best were uncertain.

Supply— Supplies are not necessarily where demands are and localized shortages exist, especially in headwater areas. Colorado River compact entitlements are not fully utilized. In the South Platte, Arkansas, and Rio Grande Basins unappropriated water is extremely limited or nonexistent. In addition to meeting future municipal and industrial water needs, the South Metro area and northern El Paso County will need to replace approximately 35,000 acre-feet/year of non-tributary groundwater with a renewable water supply.

Environmental/Nonconsumptive Needs — Environmental and recreational values will continue to be important to the state’s economy and quality of life. Environmental focus areas were identified on 33,000 miles of streams and lakes in the state with water related environmental and recreational values. Nearly one third of these focus areas have an identified project or method to support one or more of the non-consumptive values in the area.

Local Water Projects—Local water projects, if successfully implemented, have the ability to meet some, but not all of Colorado’s 2050 M&I water needs. Implementation of these local projects is critical to meeting Colorado’s future water supply needs.

Municipal and Industrial (M&I) Gap — Colorado faces a significant M&I water supply gap in 2050. This gap is defined as the difference between the projected M&I water demands and supplies from existing sources and local water projects. The M&I gap varies between 190,000 and 630,000 acre-feet depending on the success rate of the local water projects.

In 2018, SWSI is being updated using the latest information and will it serve as the technical mainframe for the revisions of the Colorado Water Plan and the Basin Implementation Plans. SWSI 18 will provide parameters that will help plan revision teams consider a variety of scenarios based on climate variance, existing supply and demands, and population growth. This will help these teams make the revised plans, maps that truly guide Colorado and the basin’s water future. 

Want to know more?  Visit the Colorado Water Conservation boards website at  or join in the Rio Grande Basin Roundtable meetings which are held the second Tuesday of each month at the San Luis Valley Water Conservancy District, 623 Fourth Street in Alamosa. Meetings begin at 2 pm. Also visit