PRRIP North Platte 04/20/2010 - Laserfiche WebLink

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Whooping Crane Spring Migration Season (March 23 -May 10): ): Shortages to the Service's dry year flow target of 1,700 cfs, at Grand Island, are again likely to occur. If it is determined by the Service that base flows are not providing acceptable stop -over opportunities for migrating whooping cranes in the central Platte River, EA releases may be made to augment flows during this period. Late Spring Pulse Flow Period (May /June): As stated previously, improvement of spring pulse events is the Service's highest flow priority. Although this time period historically experienced elevated flows primarily due to melting mountain snowpack, the Service does not plan to pursue implementation of EA pulse flows in May or June, at present. Until new information indicates otherwise, and further planning can be accomplished, the intent is to pursue at least one more EA pulse tests in the months of February or March before considering a May or June pulse release. Summer Period (June- September): If drought conditions return/persist, flows during summer 2010 could easily be similar to those from 2003 to 2006, or the somewhat improved flows experienced from 2007 to 2009. Consideration will be given to EA releases to augment flows lower than the Service targets during the plover and tern nesting season (which continues through August 15 within this summer period). Particular consideration will be given to supplementing natural flows, if necessary, at the time when nest initiation is anticipated (possibly in early May). Past use of EA releases during this period have focused on the July -early August period when foraging demands are elevated when chicks have hatched. EA releases are "budgeted for" during the 2010 nesting season, but ultimately are to be determined by conditions occurring at that time. As mentioned in the WY09 summary section, ten tern and plover nesting sites developed /enhanced since 2006 remain available for potential nesting. If weather and flow conditions permit, others may be developed by the Service's Partners for Fish and Wildlife Program and /or PRRIP prior to the 2010 nesting season. Based on the 2007 -2009 nesting, the experience with augmenting low flows, and an anticipated likelihood of similar or increased nesting in the future, improving flows during the summer period will remain a higher overall Service priority (see Table 2). For planning purposes, approximately 30,000 of of EA release is anticipated for summer flow augmentation. Water Year 2010 EA Carry -Over: At this time, the assessment is that an adequate amount of EA water will be available in WY 10 for augmenting flows during the summer period, while carrying -over a reasonable volume of EA water into WY11. As the water year progresses, habitat, species, and hydrologic conditions, EA volume, seepage /evaporation losses, releases, and lake levels will all be monitored to determine how much EA water should be retained in Lake McConaughy for carry -over. The Service is committed to cooperate with the PRRIP in current plans for multiple, step -up spring pulse releases. Preliminary planning includes two or three EA- augmented pulse events in a five -year period beginning in 2011. Thus it is anticipated that EA releases to support achievement of the species target flows, and for other adaptive management investigations, will need to be managed carefully and balanced with the need to provide carry -over for the commitment noted above.