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February 22, 2022  |  Written by Daniel J. Condren

A Reality Check on Nebraska’s Proposed South Platte River Canal

Interstate water controversies come in all shapes and sizes, and Nebraska Governor Pete Ricketts recently conjured up a puzzling new one:  “Colorado is looking to take our water.”

This past January 10, Governor Ricketts proclaimed his state’s intent to construct a $500 million canal that would divert up to 500 cubic feet per second (cfs) of water from the South Platte River within Colorado and transport the diversions to Nebraska. According to Governor Ricketts and the Nebraska Department of Natural Resources (NeDNR), existing and planned water projects in Colorado will diminish state-line streamflows by 90% when fully implemented. Thus, the argument goes, Nebraska must immediately construct the Perkins County Canal to protect its entitlement under the 1923 South Platte River Compact. Legislative Bill 1015 to facilitate the canal’s construction is now pending before the Nebraska state legislature.

On whether Colorado water users should actually be concerned about the Perkins County Canal, it is too early to say. But in a statement to Nebraska news media, a spokesperson for Colorado Governor Jared Polis put it this way: “This canal to nowhere would clearly be a huge waste of Nebraska taxpayer money and is unlikely to ever be built. There remains time for thoughtful Nebraskans to avoid this boondoggle and focus on meaningful water policy working with partners like Colorado.”

What exactly is Nebraska claiming?

What might be lost in all of Nebraska’s hue and cry about its putative $500 million canal:  Nebraska is not alleging Colorado has violated the Compact. Instead, the canal would purportedly protect Nebraska against the threat it perceives from future upstream development.

From Governor Ricketts’ January 11, 2022 release:

  • “Colorado is currently planning nearly 300 projects and over $10 billion of expenditures to ensure no ‘excess’ water leaves its state.”
  • “The Nebraska Department of Natural Resources estimates that Colorado’s plans, when fully implemented, will cause a nearly 90% reduction in flows coming into Nebraska from Colorado.”
  • “Constructing the canal is the primary means for Nebraska to exercise our legal rights to water flows from the South Platte River. If we fail to act now, Nebraska could see sharply reduced inflows from the South Platte River.”

If the canal is constructed, then according to Governor Ricketts and NeDNR, the Compact would supposedly require Colorado to deliver 500 cfs to Nebraska throughout the non-irrigation season.

What does the South Platte River Compact actually say? 

The Compact divides the Colorado portion of the South Platte into two sections:  the Lower Section (Washington, Logan, and Sedgwick Counties), and the Upper Section (everywhere upstream of Washington County). Colorado’s only affirmative obligation under the Compact is to ensure diversions in the Lower Section do not cause state-line flows to fall below 120 cfs during the irrigation season, a requirement under which Colorado has consistently over-performed. Colorado’s 2017 South Platte Storage Study concluded that on average, in each year between 1996 – 2015, Colorado delivered ~400,000 acre-feet more than the quantity required by the 1923 Compact during the irrigation season.

The present controversy involves non-irrigation season water. Nebraska’s only basis to demand water during the non-irrigation season (October 15 – April 1) arises in Article VI. Article VI authorizes Nebraska, within certain legal constraints, to construct a canal, beginning just over the state line in Colorado, with a maximum capacity of 500 cfs. This is the canal currently in question.

However, the South Platte River Compact does not obligate Colorado to supply any particular quantity of non-irrigation season water, Nebraska’s agitation notwithstanding. Just as Article VI authorizes the canal’s construction, it also limits how much water the canal can take. The 500-cfs flowrate specified in the Compact creates a ceiling for Nebraska’s diversions, not a floor, and Nebraska’s right to take water through the yet-to-be-constructed canal is restricted by a number of conditions.

  • The canal is assigned a priority date of December 17, 1921.
  • Colorado users in the Lower Section (Washington, Logan, and Sedgwick Counties) are entitled to make storage diversions of up to 35,000 acre-feet during non-irrigation season, on which the canal cannot place a delivery call, regardless of whether the associated facilities are built before or after the canal.
  • And most importantly, the canal cannot make a delivery call on any rights in the Upper Section (everywhere upstream of Washington County’s western boundary). This is regardless of relative priority—Article VI states the canal right “shall not constitute the basis for any claim to water necessary to supply all present and future appropriations in the Upper Section[.]”

Where did Governor Ricketts get his information about Colorado’s water projects?

One source may be the South Platte Basin Implementation Plan (BIP) document, which identifies 282 potential water projects totaling roughly $10 billion. The South Platte BIP was prepared pursuant to Colorado’s 2015 legislation mandating statewide water planning, and updated most recently in January of 2022. By design, the BIP is essentially a brainstorming compilation of potential projects—it is a high-level planning document, and does not actually authorize or fund any of the projects. And regardless, water consumed by any such projects located in the Upper Section is—by the express terms of Article IV—excluded from Nebraska’s Compact entitlement.

Where NeDNR came up with its conclusion—that when complete, Colorado’s existing and yet-to-be-built projects will reduce state line flows by 90%—is less clear. At present the only publicly-available source for the claim appears to be this NeDNR fact sheet, which incorrectly concludes that based on the 2017 South Platte Storage Study, “Colorado’s apparent interpretation of the Compact is that without the Perkins County Canal Colorado is allowed to reduce the South Platte River flows by approximately 90%”:

What does this all mean for now?

Essentially, hang tight and monitor the situation for developments. The Nebraska legislation, LB1015, can be tracked here.

For more detail on the issue or questions about how it may affect your existing or future projects, please reach out to Sarah Klahn ( or Dan Condren ( in our Boulder office.

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