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r <br />r <br />1 <br />ll <br />1 <br />1 <br />Il <br />L� <br />1 <br />1 <br />ANALYSES AND REPORT <br />This study analyzed: <br />The current situation.— Changes in groundwater levels stem from a variety of changing <br />factors. This study analyzed these factors to form a better picture of the causes for <br />current high groundwater levels. <br />Possible future. —The Program is determining potential alternatives for improving land <br />and water habitat. This study assessed the effect of future Program flows on ground <br />water levels. <br />DATA COLLECTION <br />In order to examine "real time" relationships between rainfall, river levels and ground <br />water levels, Reclamation in cooperation with the Central Platte NRD, the Tri -Basin <br />NRD, and the U.S. Geological Survey initiated an intensive data collection program in <br />the Central Platte Valley in March 1999 and continuing through 2000. <br />• Rainfall.— Precipitation data were taken from NEXRAD radar images that can be <br />translated into estimated precipitation amounts on a daily basis. <br />• Ground water levels.— The Central Platte and Tri -Basin Natural Resource Districts <br />established a series of eight lines, or transects, of monitoring wells across the <br />Platte River. On March 11, 1999, Reclamation installed continuous electronic <br />data loggers on 26 of the wells, which recorded the water level in each well once <br />every hour through September 17, 1999. On March 5, 2000, recorders were <br />installed on 16 of the wells. Figure 7 shows the locations of all the wells that <br />Reclamation monitored in each year, and the locations of the USGS transects used <br />in the May 25 -27, 1999, snapshot. <br />In addition, the USGS developed a snapshot of ground water elevation for the <br />entire Central Platte Valley for the end of May 1999. Between May 25 and 27, <br />1999, USGS personnel measured groundwater levels in 77 irrigation wells next to <br />the Platte River and surface water levels at 35 locations along the Platte River. <br />These water levels were measured when little widespead rainfall had occurred and <br />river discharge was believed to be affected minimally by upstream rain events. <br />• River Levels. — Hourly river stage data were recovered from the USGS web site <br />for the transect pairs near Overton, near Kearney, and near Grand Island gauges on <br />the Platte River for the same period that the wells were monitored. <br />Ground Water and River Flow Analyses <br />