The Governance Committee of the Platte River Cooperative Agreement

The U.S. Fish & Wildlife Service’s Instream Flow Recommendations for the Central Platte River

Q: What are the Fish and Wildlife Service’s target flows for the central Platte River?

A: Prior to the Cooperative Agreement, the U.S. Fish and Wildlife Service (FWS) developed recommendations for flows that it believes are needed at different times of the year for endangered species and other wildlife. The recommendations vary season by season and year by year depending on whether wet, dry or “normal” conditions exist.

The table below summarizes the flow recommendations that were developed by the FWS in March 1994 for a “normal” year:

USFWS Instream Flow Targets for the Central Platte River
“Normal Year”
Target Flow
Jan. 1 – Jan. 31
1,000 cfs*
Fish community, bald eagle
Feb. 1 – March 22
1,800 cfs
Sandhill crane, fish community, bald eagle
March 23 – May 10
2,400 cfs
Whooping crane, fish community, piping plover, least tern, sandhill crane
May 11 – Sept. 15
1,200 cfs
Fish community, least tern, piping plover
Sept. 16 – Sept. 30
1,000 cfs
Fish community
Oct. 1 – Nov. 15
1,800 cfs
Whooping crane, fish community
Nov. 16 – Dec. 31
1,000 cfs
Fish community, bald eagle
*Cubic feet per second

The FWS believes that the studies on which it based its current flow recommendations were the best scientific information available at that time on species needs. However, new and better science will be developed through the Cooperative Agreement effort or during implementation of a future Program and has the potential to reduce the flow recommendations.

Q: What are “pulse flows”?

A: “Pulse flows” are higher natural flow events now occurring that the FWS would like to preserve. The FWS believes that “pulse flows” are needed between February 1 and March 31, and May 1 to June 30 in some years to maintain wet meadows, the river channel, least tern and piping plover nesting habitat and pallid sturgeon habitat. They include very high flow events (above 12,000 cubic feet per second (cfs) and in come cases above 16,000 cfs) that last a few days and more moderate flows of 3,000-3,600 cfs lasting for a week to a month.

Q: Would Program water be used to create “pulse flows” which could cause or aggravate out of bank flooding?

A: The FWS has committed never to use Environmental Account water to create short duration, very high flow events. While the FWS would like such pulse flows to continue to occur naturally, it has no plans to augment flows to raise them to or near 8,000 cfs or any higher flow rate. In fact, both the Environmental Account Plan and the Central Nebraska Public Power and Irrigation District’s license forbid releases that would cause or aggravate flows above the flood stages as established by the National Weather Service. This means that Environmental Account releases from Lake McConaughy, in combination with other releases and other North Platte flows, cannot exceed 3,750 cfs, which is flood stage on the North Platte River at North Platte (the lowest flood stage). Similarly, Environmental Account releases from Lake McConaughy, in combination with other releases and other Platte River flows cannot exceed 8,200 cfs, the flood stage for the Platte River at Grand Island, or any other flood stage on the Platte River. Thus, while the FWS may occasionally use the Environmental Account to enhance naturally occurring, longer, lower flow pulses to make them more like the recommended 3,000-3,600 cfs “pulse flows,” bank overflow will only occur because of natural high flow events.

Q: What is the 417,000 acre-feet number people hear about and what does it mean?

A: The 417,000 acre-feet (a-f) number is the average annual amount of water needed to eliminate “shortages” in existing flows compared to those that the FWS recommends. The recommended flows are a combination of the target flows listed in the table above plus some water for the lowest level of “pulse flows” described in the previous question (see graph).

The 417,000 a-f figure was calculated using actual flows from the past (1943 to 1994). During that period, there were some years when the recommended flows were met much of the time and other years when they were seldom met. Even in months where average flows were well above the recommended flows, day-to-day variations in flows often meant that flows fell short of the recommendations on some days. Looking only at the days when flows fell short and averaging the annual “shortages” results in the 417,000 a-f figure. Days when flows were higher than the recommended flow were not used to offset the shortages, because in the past, the excess water just flowed on downstream. But if that excess water could somehow be saved and put into the river on days when flows are below the recommendations, shortages could be reduced without increasing the annual river flows.

The problem therefore is largely one of timing, not of total supply. To the extent methods are found to re-time the water that is now in the river, additional water will not be needed.

Q: How could flows be brought closer to target flows?

A: If flows throughout the Platte River Basin could be re-timed or re-regulated (moved from periods when flows are higher than recommended to times when flows are lower than recommended), flow recommendations could be met much more often. For example, the three proposed Program water projects (the Nebraska Plan’s Environmental Account in Lake McConaughy, the Pathfinder Modification in Wyoming and the Tamarack Plan in Colorado) would bring flows about 70,000 a-f closer to the recommendations by re-regulating flows without increasing the annual flow at all. Additional re-regulation projects, water conservation and new water supply opportunities can bring flows even closer to the recommendations.

Q: Has the Fish and Wildlife Service changed its position on requiring target flows because of the Cooperative Agreement and proposed Program?

A: Yes. Before there was a Cooperative Agreement, the FWS was proceeding project-by-project seeking mitigation based on its recommended target flows and seeking to reduce shortages to the target flows by 417,000 a-f. In the proposed Program, the FWS has agreed to an incremental, adaptive management approach. During the first 10- to 13-year increment of the proposed Program, the goal is to provide 130,000 to 150,000 a-f per year to move flows closer to the FWS’s recommended flows. New and better science will be developed through the Cooperative Agreement effort or implementation of a future Program and has the potential to change the flow recommendations.

Q: How would the Fish and Wildlife Service proceed under the Endangered Species Act if there were not a Cooperative Agreement?

A: If there were no Cooperative Agreement, there would instead be individual, full-blown, project-by-project consultations under the Endangered Species Act. The FWS would base its consultations on the current target flows and seek measures to reduce or eliminate the 417,000 a-f “shortage” to its recommended flows, unless new scientific information demonstrated that a change to these target flows was needed. This approach would likely result in project delays and would be more likely to result in inequity and litigation.

Q: Have all the other signatories and participants in the Cooperative Agreement agreed to the Fish and Wildlife Service’s pre-Cooperative Agreement recommendations?

A: No. Many of the participants have conducted their own studies of the river and species and some have reached conclusions which do not agree with those reached by the FWS. All three of the states that signed the Cooperative Agreement and many of the other participants disagree with some or all of the FWS’s views. The unique feature of the Cooperative Agreement is that the parties have been able to set aside fundamental conflicts about species needs, target flows and even the Endangered Species Act itself to make a plan that will reevaluate the science while beginning to take steps to benefit habitats.

In embracing the Cooperative Agreement process, the participants have concluded that, whether or not they agree with the FWS, project-by-project litigation would be likely without a Program. Such litigation — particularly in opposition to a federal agency considered to have expertise — carries a risk that it will not be successful. The proposed Program also responds to new information about the complex relationships among flow, habitat and species recovery. Court orders would not.

Q: Where can the general public make its views known and obtain information on the latest developments?

A: The general public can make its views known and obtain information on the Cooperative Agreement and Program by contacting Governance Committee members and subcommittee chairs, attending committee meetings, contacting Dale Strickland, the Governance Committee’s executive director (toll-free phone number: (877) 634-1773), or checking the Governance Committee’s web site at