Free River! We have it now; what is it?
Free River!
While free river conditions are more common in some drainage basins in Colorado, e.g., the Yampa and White Rivers, it is not as common in the South Platte River. However, the late spring wet weather along the Front Range, coupled with the annual spring runoff, have provided an extended free river condition for much of the South Platte River Basin. Free river conditions started on May 12, 2023 and continue to date (June 10, 2023), although a relatively junior call with an appropriation date of 1985 was placed on May 11, 2023.
What is free river?
Free river is determined by the Division Engineer’s Office, the administrator of water rights, when all vested surface water rights are satisfied. Therefore, under the Doctrine of Prior Appropriation (“Doctrine”) [see 6/9/20 LWS blog], when all senior water rights have their full water supply and there is still water available to also satisfy all junior water rights, no “call” on the river is necessary, aka a free river.
When the water supply in the Basin’s rivers and creeks is more limited, the Doctrine allows senior water rights to fully satisfy their rights prior to any junior water rights obtaining water. During these times, many junior rights are “called out” [see 3/5/20 LWS blog on Real Time Data Resources], which means they cannot divert any water so the senior rights can get their full appropriations. The Doctrine in Colorado varies from riparian water rights in other states, where water availability is shared based on land ownership along streams [see 7/28/20 LWS blog on CO Water Law Basics: Prior Appropriation…Riparian Water Rights].
Because the Doctrine allows each right to be fully satisfied in the order of their priority, with the most senior priority satisfied first before the next right in priority is allowed to take any water, free river is particularly important for more junior rights in a system that is generally over-appropriated in times of average or below average flow.
Example: Rueter-Hess Reservoir
A good example of a junior water right seeing great benefit from free river is Rueter-Hess Reservoir in Parker, Colorado. Located on a tributary of Cherry Creek which, in turn, is a tributary to the South Platte River, this 1985 priority water right has limited times of in-priority flow that can be diverted into storage.
Rueter-Hess Reservoir, Douglas County, Colorado
Rueter-Hess Reservoir is a key component of the Parker Water and Sanitation District (“PWSD”) water supply, providing renewable water that can be stored during times of availability and then put to beneficial use to meet its customers’ needs, as needed later in time. Rueter-Hess Reservoir is also more than a storage facility to divert in-priority stream flows, it is also used to allow PWSD to operate a full water reuse system. Rueter-Hess can capture an equal volume of water from Cherry Creek as the volume of reusable water reclamation effluent that is discharged to Cherry Creek. In this way, PWSD obtains multiple uses of water to provide an extremely efficient water supply system.
Figure 1 shows the storage contents in Rueter-Hess in 2023. As a water supply reservoir, water levels are expected to fluctuate over time as multiple sources of water are stored, while water is also released from storage to the PWSD water purification facility for treatment, and then used by PWSD residents. Until May 11 there had not been any in-priority water available for storage in Rueter-Hess in 2023. Therefore, the only sources of water that could be stored were related to its water reuse system. When a call junior to RHR’s 1985 storage right was placed on May 11th, RHR was able to not only divert and store native Cherry Creek water but also store precipitation and runoff associated with storm events. As shown in Figure 1, with the combined high flows and free river conditions, Rueter-Hess has stored over 1,811 acre-feet of water in the 28 days of free river!
How important is this?… A typical single-family home uses approximately 0.4 acre-feet of water per year, so the amount of water stored in 28 days represents a full year’s water supply for about 4,528 homes!
Hopefully, with spring runoff also ongoing for some time yet, free river conditions will continue and more water to serve Colorado’s residents can be captured at Rueter-Hess, as well as by other more junior water rights that don’t have long periods of in-priority flows.
If you are in need of any water resources engineering services, including development of new or existing water rights, please give us a call at 303.350.4090 or email. We will be happy to talk to you about your water resources challenges and develop a proposal tailored to your needs, free of charge.
Bruce Lytle, P.E. bruce@lytlewater.com
Chris Fehn, P.E., P.G. chris@lytlewater.com
Ben Bader ben@lytlewater.com
Anna Elgqvist anna@lytlewater.com
