Water Year 2002 EA AOP with Membership List

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Winter/Early Spring (December-March): Nebraska experienced normal to above average winter conditions during the 2001 water year, with colder temperatures, extensive river ice formation, and plains snow cover. Although these conditions helped to replenish depleted soil moisture, no significant spring rise (i.e., pulse flows) occurred in the central Platte River during the 2001 water year. In the absence of scouring andfor longer duration pulse flows in the last two water years, establishment of vegetation on low sandbazs within the channel has been extensive. As a result, numerous EAC representatives and others have indicated an increased interest in using the EA to augment or create pulse flows to facilitate removal of in-channel vegetation and promote other river processes. Therefore, if conditions are conducive for using the EA to facilitate a pulse flow during this time period, EA water will be used for this purpose. Due to the many uncertainties associated with using the EA for pulse flow management, the EA manager will malce every effort to investigate and coordinate the necessary details before implementation of such an activity. Whooping Crane Migration Season (March 23-May 10): Flow projections indicate that average and/or dry targets will not be met. If it is determined that low flow conditions are not maintaining adequate base flows to provide stop-over opportunities for migrating whooping cranes in the central Platte River, EA releases will be made to augrnent flows during this time period. Late Spring (Mayl3une): If conditions during winter/early spring (with or without EA releases) have not resulted in beneficial pulse flow(s) which promote natural river processes (e.g., in- channel vegetation removal, sandbar farmation), opportunities to augment May/June flows will be prioritized. Improvement of late spring pulse events is the Service's highest flow priority (Bowman 1994; Bowman and Carlson 1994). Existing long-term averages for pulse flows are well below Service targets, current projections suggest that below average flow conditions will again occur throughout most of the water year, and no spills are predicted. Mountain snow accumulation, and the timing and duration of uncontrolled runoff in May and June, will be monitored for opportunities to use EA releases to augment runoff events to improve the magnitude and/or 30-day duration of peak flows to remove in-channel vegetation. Summer (June-September): To the extent that predictions for summer 2002 are practical, flows are projected to be below both Service-recommended average and dry flow targets through September. The dry year prediction and projections indicate that irrigation demand and summer flow conditions could be similar to those experienced in Water Years 2000 and 2001. During those two summers, extremely low flow conditions were experienced at Grand Island even with EA releases (e.g., for ten separate days in August and September 2000, flows at Grand Island dropped below 500 cfs even though 550 cfs was being released from the EA; in June and July 2001, flows dropped below 300 cfs for 15 consecutive days while between 200 to 550 cfs was being released from the EA). A portion of the EA will be retained for use during the summer to augment extremely low flow periods to maintain fish/aquatic community health and a forage base for the least tern. Carry Over: Carry Over of EA water from one water year to the next allows for use of the EA d.uring the early months of the non-irrigation season before additional water is accumulated or to Water Year 2002 EA AOP 7 January 7, 2002