Laserfiche WebLink
<br />. Buffers were used to incorporate a factor of safety in the decision to store or <br />release. If the flow at Overton was more than 200 cfs above the target flow, then <br />water was diverted to storage, If the flow at Overton was more than 500 cfs below <br />the target flow, then water was released from storage. Changes to these buffers will <br />affect yield results. <br /> <br />. Incremental changes in gains and losses between Overton and Grand Island are <br />negligible, <br /> <br />. Rainfall falling on water surfaces was assumed to be added to the reservoir volume <br />in full, Historical daily precipitation data was obtained from the Holdrege weather <br />station. <br /> <br />. Runoff contributed from rainfall falling on the drainage basin surrounding the <br />reservoirs was subject to SCS losses, Antecedent moisture conditions were used. <br /> <br />. Seepage through the dams was estimated using Darcy's Law and the geometry of <br />the dam along with soil characteristics. Daily seepage rates were based on the <br />water surface elevation at the beginning of the day. <br /> <br />. Evaporation was based on available climate data for the North Platte weather <br />station, A constant water surface area of one-half the reservoir depth was used for <br />each reservoir for the purpose of determining evaporative losses and direct rainfall. <br /> <br />. The reservoirs began the study period empty. <br /> <br />. Inflow and outflow capacities were preliminarily set by conversations with <br />CNPPID. Fill capacities ranged from 100 to 400 cfs, while release capacities were <br />set a 50 cfs for all reservoirs. Changes to these capacities will affect yield results. <br /> <br />. No freeboard was used in the hydraulic and hydrologic analyses. Water was <br />considered to be spilled in full beyond the normal volume of the reservoir. <br /> <br />. Water was available in the Canal up to the amount of the historic J-2 return during <br />periods when diversions into the reservoirs were made, The water diverted from <br />the Canal to be stored in the reservoir could not exceed the flow in the J-2 return, <br /> <br />Daily reservoir operations data, including diversions to storage and releases, have not yet <br />been made available by HDR and CNPPID. <br /> <br />o Legal And Institutional Requirements for Implementation: <br /> <br />There may be several legal and institutional requirements necessary to implement any of <br />these reservoirs, As noted by NPPD in comments received May 3, 2000, the operational <br />rules must insure that all senior water right demands are met before storage is considered <br />or credited to a CNPPID re-regulating reservoir. This condition should be met if water is <br />only available for storage on days that flows downstream of the J-2 Return exceed the <br />needs of existing water rights, <br /> <br />C:\Drilfl Wllter Action Plnn (May 30, 2000)\wllpc llliX)tt (Version 6 BND2)-.dol: <br /> <br />12 <br />