Publications / 2011 Front Range Water Supply Planning Update

2011 Front Range Water Supply Planning Update

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The issue of transmountain water diversions in Colorado is both extremely complex and controversial. In the former respect, it must be noted that this report provides only a general review of the potential for increased transmountain diversions from the Roaring Fork Watershed, examining existing conditional rights, undeveloped and underutilized project infrastructure, and the potential utility of increased diversions on the Front Range for the corresponding owners on local transmountain diversion systems. The hydrologic availability of such increased diversions – with, for example, increasing West Slope water demands and changes to the nature and volume of runoff – is a technical matter necessarily beyond the scope of this report. General, widely accepted assumptions regarding hydrology are applied where appropriate, but as the report‟s recommendations make clear, additional technical research is needed to confirm the physical availability of the increased transmountain diversions that this report explains are legally available. Some of the potential additional diversions discussed in this report, for example with the Busk-Ivanhoe System, may be relatively small and occur only in years with above-average precipitation. Yet this report is intended to provide a comprehensive overview of the potential for additional transmountain diversions, and thus does not overlook potential additional diversions, even if they may be individually small.

With respect to the controversy surrounding the topic at hand, this report is intended to be a neutral examination of the legal feasibility of additional transmountain diversions from the Roaring Fork Watershed, which necessarily must be viewed from the larger, statewide context. Thus, the discussion of current developments among Front Range water providers is intended solely to explain that both the physical capacity and practical need for increased transmountain diversions exist on the East Slope – and are increasing.

The purpose of this paper is not to prevent additional transmountain diversions or even to raise alarm over such a possibility, but rather to spur local water interests in the Roaring Fork Watershed, especially local governments, to remain active and committed to this issue. With the current economic downturn, the financial and human resources of local governments are becoming increasingly limited, and all indications suggest the current economic situation must be viewed as “the new normal.”1 Despite increasingly constrained budgets, the pressures and demands on these institutions are growing, as the region‟s population and demand for public services continues to expand. Issues such as aging public infrastructure, land-use planning, and economic development all compete for the time and attention of local officials, which means that issues like transmountain diversions can easily be lost amid the clamor of local politics. Yet the current status and nature of statewide water supply planning requires that local interests remain vigilant and active in this area.

As this report explains, under the Interbasin Compact Process, water supply planning in Colorado is now based on cooperative efforts at the local level. Thus the ability of water interests on the West Slope to respond to transmountain diversion proposals depends on local interests working together as a collective force to negotiate with powerful Front Range water interests. For example, as Denver Water and the Northern Colorado Water Conservancy District have pursued their respective plans to divert additional water from the headwaters of the Colorado River via the Moffat Collection System and Windy Gap Firming projects, local public institutions and water interests in Grand County have collaboratively worked to identify a range of measures to mitigate the potential impacts of the proposed increased diversions.2 Though the process has been at times contentious and is still far from complete, the collaboration among local interests has proven key to having their concerns with the project adequately addressed. While there are no current specific proposals for diverting additional water from the Roaring Fork Watershed, as this report explains, the plans and legal conditions for such diversions do exist, and local interests can rightly expect such proposals to eventually surface. Therefore, local interests should continue to collaborate in planning and preparing for this possibility, for which intergovernmental entities like the Ruedi Water & Power Authority constitute an effective and cost-efficient means of cooperating on this issue.



Three major transmountain diversions currently operate in the Roaring Fork Watershed – the Fryingpan-Arkansas Project (“Fry-Ark Project” or “Fry-Ark”), the Busk-Ivanhoe System, and the Independence Pass Transmountain Diversion System (“Twin Lakes System”) (see inset). At present, these three systems collectively divert over forty percent of the flow in the headwaters of the Roaring Fork and Fryingpan rivers for use in the Arkansas and South Platte basins. Although these diversions have been in operation for decades, each of the projects are still incomplete, with undeveloped conditional water rights, excess diversion capacity, and even major structural components that could yet be built.

According to the Colorado Water Conservation Board‟s most recent estimates, the Arkansas and South Platte basins are facing a combined shortfall in water supply of at least 130,000 acre-feet of water (and potentially as great as 470,000 acre-feet) by 2050, due to the influx of another 3.2 to 4.5 million new residents by that time.3 To meet this projected gap, Front Range water providers are scrambling to secure additional sources of water. For many of them, the options for new water supplies are limited: most of the rivers on the East Slope are already over-appropriated; groundwater supplies are declining in some areas due to excessive well pumping; and in recent decades, the costs and uncertainty surrounding new transmountain diversions have prevented many such projects from being built.

For many Front Range water providers, firming up existing transmountain water rights and maximizing the diversion capacity of existing infrastructure is likely to represent one of the most cost-effective, publicly acceptable means of developing additional water supplies. Local interests in the Roaring Fork Watershed should therefore expect Front Range water providers to eventually attempt to firm up undeveloped water rights and excess diversion capacity associated with the Fry-Ark Project, Busk-Ivanhoe System, and Twin Lakes System. In fact, such efforts may already be underway on the East Slope.


Water Supply Developments on the Front Range Relevant to Local Firming Efforts:

  • Demand for increased East Slope storage capacity in order to allow for the diversion and carryover storage of “surplus flows” from years with above-average precipitation as protection against times of severe drought.
  • Recent discussions by board of directors for the Southeastern Colorado Water Conservancy District concerning structural improvements to the Fry-Ark‟s West Slope collection system, in order to make up for the 14,400-acre-foot “gap” in the project‟s current yield. 
  • Potential opportunities to expand Busk-Ivanhoe diversions arising from the City of Aurora‟s recent application for the change of use of its portion of the Busk-Ivanhoe System water rights.
  • The likelihood of increased Twin Lakes System diversions in years with above-average precipitation, due to increased East Slope storage capacity and water demands – as well as in years with average and below-average precipitation, with continued improvements to the Twin Lakes System‟ West Slope collection infrastructure, including the development of the system‟s remaining conditional water rights. Recommendations for the Ruedi Water & Power Authority
  • Continue to serve as the collective voice of local water interests in the Roaring Fork Watershed, particularly in negotiating with Front Range water providers over their use of local water supplies (Recommendation 1.1).
  • Continue to support water-related research and analysis (Recommendation 1.2).
  • Encourage, support, and facilitate the lawful appropriation of local water resources for beneficial use, such as, for example, recreational in-channel diversions (Recommendation 1.3). Short-term Options (2010-2015)
  • Support technical research on the following issues: o Potential hydrologic impacts to flows in the Roaring Fork Watershed with pending and proposed changes to East Slope water storage and conveyance infrastructure; and o Potential economic impacts to the local economy associated with future releases from Ruedi Reservoir under full contract demand (Option 2.1).
    • Procure financial and technical support for local watershed planning and management efforts (Option 2.2).
    • Support and advocate for the watershed‟s interests at the State and Federal level (Option 2.3).
    • Investigate the possibility of allocating a portion of water in Ruedi Reservoir to meet the state‟s Colorado River Compact delivery obligations (Option 2.4). Medium-term Options (2015-2025) • Pursue potential opportunities to improve flows below the Busk-Ivanhoe System and Twin Lakes System (Option 3.1).
  • Consider potential reformatted uses of the water rights connected to the Basalt Project (Option 3.2)

Contact Us

Roaring Fork Conservancy

PHONE: (970) 927-1290

PO Box 3349
Basalt, CO 81621

22800 Two Rivers Road
Basalt, CO 81621

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