Water Action Plan and Three State Projects Draft

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Water Leasiniz and Water Manaizement Incentives (Yield to EA = 15.9 kaf + Western Canal reduction of 0.947 kaf) Projects of these types basically involve reductions in consumptive use and depending upon the location, the "saved" water may or may not be directly available to the McConaughy Environmental Account. For example, the Western Canal (Boyle reach 10) does not receive storage water from Lake McConaughy. Therefore, Water Leasing and Management Incentives in that reach are related to reductions in natural flow diversions combined with recognition of the saved volume and protection from diversion for consumptive use. The Western Canal volume associated with Leasing/Incentives averaged 947 acre-feet per year. The other reaches in the Boyle report were translated into the corresponding OPstudy reaches and the reduction in consumptive use assumed to be from reduced storage deliveries: Keystone - Sutherland Canals (North Platte River) 898 acre-feet Sutherland - North Platte Canals (North Platte River) 268 acre-feet Brady - Cozad Canals (Platte River) 1,558 acre-feet Central District (Platte River) 12,217 acre-feet Kearney Canal (Platte River) 221 acre-feet The sum of the savings in consumptive use (except for the Western Canal) is 15,160 acre-feet. This volume was allocated annually to the EA in each October. The Boyle report recognizes that to achieve a certain volume of consumptive use reduction, a larger reduction in on-farm deliveries is needed in order to provide previous levels of return flow to the system. By modeling the reduction in Consumptive Use, the OPstudy model is consistent with Boyle's analysis. Ground Water Mana e?ment (Amount stored below J2 area = 2.8 kaf, amount credited to EA = 4.5 ka fl Option 4 in the Boyle report (conjunctive use project in CNPP&ID area) was used as a representative project. An annual target storage volume of 3,500 acre-feet was used in the OPstudy model, and diversion from the J2-return flow available was allowed during the non- irrigation season when excess occurred. The average annual volume stored over the study period from excess was approximately 2,800 acre-feet and it was assumed that this volume was subsequently pumped during the irrigation season to meet demands. Accounting for losses in the NPPD and Central District systems resulted in an average of 4,500 acre-feet being credited to the Environmental Account. Lost Creek/North Dry Creek Cutoff (2.2 acre-feet contributed to river, "score" = 1.1 ka fl This project was simulated by introducing water into the OPstudy model above Kearney (in the Overton - Odessa reach of the model). A maximum inflow rate of 500 acre-feet was allowed whenever instream flow excess was occurring during May thru September. This is somewhat higher than the 440 acre-feet volume identified by Boyle in Table III-26 in order to achieve a yield closer to that identified in the draft plan (2,200 acre-feet). Because the water enters in the mid-section of the habitat, the final score was 50% of the volume introduced.