The Central Nebraska Public Power and Irrigation District’s facilities consist of Lake McConaughy, Supply Canal, and Irrigation System, along the North Platte and Platte Rivers downstream from the North Platte Natural Resources District. Central’s system and water supply provides numerous benefits, including: deliveries to over 100,000 acres of land that irrigate directly from Central’s system, located primarily in Gosper, Phelps, and Kearney Counties; irrigation storage water for an additional 100,000 acres on 11 other canal systems in Lincoln, Dawson, Keith, Garden, and Morrill Counties; hydropower generation at Central’s Kingsley, Jeffrey, Johnson No. 1 and Johnson No. 2 hydropower plants; hydropower generation or cooling water for Nebraska Public Power District’s North Platte Hydro, Gerald Gentleman Station, and Canaday Steam Plant; recreation at numerous reservoirs, including Lake McConaughy, Lake Ogallala, Jeffrey Lake, Midway Lake, Gallagher Canyon Reservoir, Plum Creek Canyon Reservoir, Johnson Lake, and Elwood Reservoir; aquifer recharge in accordance with underground storage appropriations to more than 1,000,000 acres in Gosper, Phelps, Kearney, Lincoln, Dawson, and Frontier Counties; return flows to the Platte River; an Environmental Account for use for threatened and endangered species on the Platte River; flow contributions to the Republican River that provide a credit for Nebraska under the Republican River Compact; and wintertime open water for bald eagle feeding. Central operates in accordance with appropriations granted by the State of Nebraska, contracts with customers, and a hydropower license from the United States Federal Energy Regulatory Commission.
Though Central has a number of direct-flow appropriations for irrigation and hydropower production, because of the very junior priority dates of those appropriations, storage water in Lake McConaughy is critical to Central’s operations and the many benefits just listed. Lake McConaughy relies almost exclusively on the marginal flows of the North Platte River; particularly that streamflow originating within the North Platte NRD as a result of the movement of water from the aquifer to the river and its tributaries. In the original case of Nebraska vs. Wyoming, consideration had been given to the question of whether or not a part of the water supply then in question should be assigned to downstream interests; with the Special Master ultimately determining that it would not be necessary for the specific reason that it was expected that downstream interests would be able to rely on these marginal flows of the North Platte River, and be able to store such flows in Lake McConaughy.
Pumping from wells in the North Platte NRD is depleting the North Platte River streamflow at a current rate of over 125,000 acre-feet per year, and the amount continues to grow. As a matter of comparison, this is equal to 14 percent of the normal inflow into Lake McConaughy, 23 percent of the inflow into Lake McConaughy during the current drought, 139 percent of Central’s normal average irrigation deliveries, and 287 percent of Central’s average irrigation deliveries during the current drought. As a result of the depletions caused by pumping in the North Platte NRD, Lake McConaughy contents, irrigation deliveries, hydropower generation, cooling water availability, water levels for recreation, aquifer recharge, Platte River return flows, Environmental Account contributions, flows to the Republican River basin, and open water for eagles have all been reduced. It is addressing these streamflow depletions and the resultant adverse impacts which should be the focus of the integrated management plan for the North Platte NRD.
The proposed IMP fails to respect the rights of prior appropriators. With rare exception, hydrologically connected wells in the North Platte NRD, and their depletions to streamflow, are junior in time to most appropriations within and downstream from the North Platte NRD. The IMP should include goals, objectives, or actions that would protect the rights of senior appropriators. Through the IMP, the Nebraska Department of Natural Resources and the North Platte NRD should quantify impacts to senior appropriations, quantify amounts of use reasonably expected to avoid impacts to senior appropriations, manage well uses in a way that avoid or reduces impacts to senior appropriators, provide replacement water for impacts that are not avoided, enter into interference agreements with senior appropriations, or compensate senior appropriators for impacts to their water supply.
The proposed IMP fails to resolve conflicts between ground water uses and surface water appropriators. According to § 46-703 of the Nebraska Ground Water Management and Protection Act, it is the intent of the legislature that the DNR and NRDs identify and implement management solutions to such conflicts. In no other NRD in the Platte River basin is conflict between ground water and surface water uses more apparent than in the North Platte NRD. Surface water users on Pumpkin Creek are currently in litigation against well owners in that watershed for drying up that stream, and Central has raised similar complaints about the impacts of those wells as part of those proceedings. Central has previously brought a complaint against hydrologically connected wells located upstream from Lake McConaughy. Streams, ponds, and wetlands within the North Platte NRD are drying up. The many downstream uses that are being hurt by North Platte NRD streamflow depletions have been described earlier in this testimony. Notwithstanding all of this, the draft IMP does not identify any management activities that would resolve these conflicts. The draft IMP does contain some reference near the end to a process in the Basin-Wide IMP whereby aggrieved parties can supposedly bring a complaint and have the conflict addressed through changes to the IMP; but since the conflicts within the North Platte NRD are already well known and yet are not addressed, it seems questionable to expect that those same conflicts raised again in the future will be given any different treatment, which is no treatment at all.
The proposed IMP significantly underestimates streamflow depletions caused by wells in the North Platte NRD. The IMP uses results from certain Cooperative Hydrology Study models for estimates of streamflow depletions. COHYST is a major, collaborative, multi-year effort to improve our understanding of Platte River basin hydrology in Nebraska. Central supports this effort, and is one of the many COHYST Sponsors. However, the current COHYST models are known to have a number of limitations or other problems that make it inappropriate for them to be used for estimating streamflow depletions at this time. Problems with these models include such things as not including any impacts associated with supplemental or co-mingled wells, projecting depletions based only on average rather than variable water supplies and uses, reliance on a so-called “recharge bump” that artificially adds water to the system and masks the impacts of well development, and lacking a proper streamflow calibration. These problems are not new; they have been known to the COHYST members, including the North Platte NRD and the DNR, for quite some time. And the consequences of these model deficiencies are not insignificant. Indeed, when Central hired an outside modeling expert to incorporate changes into the models to address these same identified issues, the results were quite dramatic. The result was an estimate of depletions now at a rate in excess of 125,000 acre-feet per year, approximately four times greater than the approximately 32,000 acre-foot estimate reported by the Nebraska Association of Resources Districts in 2007 based on the COHYST models in their current flawed form. The obligation to use the best available science is not satisfied simply by using the newest models available, but requires also that deficiencies and limitations in those models be acknowledged and accommodated. The DNR and NRD should modify the COHYST models to address these issues before using the depletion estimates in the IMP; should adjust the model results to account for the known model deficiencies; or should adopt some other methodology instead of, or in addition to, the models for estimating depletions.
The proposed IMP overestimates offsets resulting from surface water retirements in the North Platte NRD. Under the draft IMP, there is a total and immediate offset credit given for discontinued use of surface water or co-mingled irrigation, such as may occur through the Conservation Reserve Enhancement Program, the Environmental Quality Incentive Program, the Agricultural Water Resources Enhancement Program, or the Platt Basin Habitat Enhancement Program. Such a crediting for these reduced surface water uses is completely inappropriate. First of all, it is improper to assume that all retired surface water uses would have had a full supply of water to begin with, because many surface water users could have a limited available supply from natural flow or storage water from time to time. Indeed, water-short irrigators are among those most likely to sign up for such irrigation-idling programs, and there certainly is no logic at all in assuming a one-hundred percent surface water use for those lands that have seen the need to install a supplemental or co-mingled well. Additionally, it is simply not true that the forgone surface water use, whatever amount it may be, will just remain in the river to serve as an offset for some other depletion. More likely, the unused water will instead be used by remaining irrigators of the same irrigation canal, be diverted by the next water-short appropriator in order of priority, or retained in upstream storage for use at some future date. Any offset credits for surface water retirements should be limited to those appropriations that actually go through a transfer in accordance with surface water statutes, or that amount of water that the DNR can actually determine to be in the river at the appropriate time and location after adjusting for actual available supply and ultimate disposition of the unused water.
The IMP improperly focuses on averages in the estimation of depletions and offsets; failing to take into consideration hydrologic variations from season-to-season and year-to-year. Timing of water availability is critically important in the Platte River. Water supplies in the Platte River system are highly variable. The amount of water used by wells, and consequently depleted from the stream, goes up and down in relation to supply. In other words, as growing-season precipitation or surface water supplies available for North Platte NRD water users decrease, the amount of well pumping and depletions to streamflow increase. Likewise, as precipitation or surface water supplies decrease, the harm caused to other users by streamflow depletions is increased. Unfortunately, the IMP only estimates depletions, and therefore only identifies a need for offsets, in terms of annual averages. The consequence is that in times of shortage, such as the current drought, the estimated average streamflow depletion is greatly understating the amount of depletion that is actually occuring, and if only the average offset is provided, there would exist in reality a significant actual depletion that is not being offset. Conversely, when there is plenty of water available in the system, the actual depletion and the need for offset may be less than the average estimate. However, providing the additional offset during this time of plenty very likely does not make up for under-offsetting during the drier times, as the users injured during the dry times may be different from, or have little need for, the additional offset at that time. Another problem with the use of the depletion and offset estimates is that they are annual. Just as water supplies and demands vary from year to year, so it is also true that they vary from season to season. Streamflow in the irrigation season most often goes first to satisfy irrigation before other demands, whereas streamflow in the non-irrigation season most often goes first to satisfy demands for storage and power generation. Depletions and offsets in the irrigation season and non-irrigation season have different consequences to different appropriations, and a contribution of flow in one season does not necessarily suffice to offset for a depletion in another. Nontheless, the IMP contains no seasonal breakdown of the depletion and offset estimates. The IMP should provide variable estimates for depletions and offsets, according to variations in hydrologic conditions and time of year, instead of just estimates based on annual averages.
The proposed IMP fails to recognize and appropriately manage for variability in the water supply. When water supplies run short, most water uses are curtailed. As mentioned previously, water supplies in the Platte River system are highly variable, with times of plenty and times of shortage. In times of shortage, surface water uses are reduced in conjunction with reductions in supply. For example, in the current drought, Central’s total hydropower production has been reduced by 57 percent, with discretionary releases of storage water for hydropower production having been eliminated altogether; Central’s irrigators have had their delivery allocation cut by at least 53 percent for the last 5 years, and by 63 percent in 3 of the last 5 years; Central has ceased use of Elwood Reservoir; and Central has reduced the amount of water made available to other irrigation districts. Also during this time, recreational users have had to endure lower water levels at Lake McConaughy and several other reservoirs, contributions to the Environmental Account have been reduced, and recharge in the Tri-Basin NRD and flow contributions to the Republican River basin have been diminished. By contrast, during times of shortage, such as the current drought, the amount of water used by wells in the North Platte NRD increases substantially; right at the time when the water supply, and other users are dependent on that same water supply, can least afford for that increase to occur. It may be that a 14-inch allocation, such as that contained in the draft IMP, is suitable when there is ample water in the Platte River system; but this use should be significantly curtailed, perhaps by as much as fifty percent, when North Platte River flows are below normal. And it should not be assumed that the system would not respond in time for such a reduction to provide substantive streamflow benefits. Modeling results using the modified models, as described earlier, show that a substantial reduction in streamflow depletions occurs in as little as five years from the onset of reduced pumping. Because most droughts often continue for several years; and because Lake McConaughy and other reservoirs have the ability to sustain downstream users for the first several years of a drought; restrictions on well pumping within the North Platte NRD at the onset of a drought will reduce streamflow depletions within time to be of benefit to the water-short system. The IMP should contain mechanisms designed to reduce well water use during times of shortage, such as reducing by half the allocation or that number of irrigated acres at times when North Platte River flows drop below 800,000 acre-feet per year.
Along with this testimony, Central also submits the following items:
Exhibit 1; “Analysis of Depletions to the North Platte River”, 2009, by Lytle Water Solutions, LLC; giving results of water budget and groundwater modeling analyses; describing adjustments made to the COHYST models to address previously identified issues with those models; estimating streamflow depletions caused by wells in the North Platte NRD; and also estimating reductions in streamflow depletions that can be achieved through reductions in pumping.
Exhibit 2; “Water Rights Audit”, 2008, by The Central Nebraska Public Power and Irrigation District; summarizing Central’s appropriations for storage, irrigation, power production, underground storage, and the Environmental Account.
Exhibit 3; “A Report of Preliminary Findings from A Study of Hydrologically Connected Ground and Surface Water and its Contribution to Conflicts between Ground Water Users and Surface Water Appropriators in the North Platte Natural Resources District”, 2004, by the Nebraska Department of Natural Resources.
Exhibit 4; “Ground Water and Surface Water A Single Resource”, 1998, by the United State Geological Survey.
Exhibit 5; “An Analysis of the 14-Inch Ground Water Allocation in the Pumpkin Creek Basin”, 2008, by Lytle Water Solutions, LLC.
Exhibit 6; “Evaluation of the Pumpkin Creek Ground Water Allocation by the North Platte NRD”, 2008, by Lytle Water Solutions, LLC.
Exhibit 7; “Adverse Effects of Pumpkin Creek Groundwater Pumping on Central District Water Uses”, 2009, by Michael Drain; report prepared for use in the case of Spear T Ranch, Inc. versus Melvin G. Knaub, et. al.; the adverse effects described in the report as caused by pumping in the Pumpkin Creek basin are likewise caused by stream depletions throughout the North Platte NRD.
Exhibit 8; “Expert Disclosures in Spear T Ranch, Inc. Versus Melvin G. Knaub, Et. Al. Case No. CI03-16”, 2009, by Lytle Water Solutions, LLC.
Exhibit 9; “Streamflow Declines Caused by Groundwater Development in Pumpkin Creek Basin”, 2002, by Michael Drain.
Exhibit 10; A 2009 letter from Lytle Water Solutions, LLC describing known issues regarding the COHYST models and evaluating the assumption in the draft IMP that surface-water and co-mingled retirements result in a 100 percent and instantaneous offset to streamflow depletions.
Exhibit 11; Various documents referenced by the 2009 letter from Lytle Water Solutions, LLC |
