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The spatial variability of the water level trends in the South Platte alluvium does not allow for <br />color-fill contouring of the water level trends so the trends have been posted by well. <br />Water level trends from spring (pre-irrigation season) measurements in the alluvium show <br />what appear to be three general patterns in the South Platte Alluvium Region. The first is that, <br />over most of the alluvial aquifer (including the mainstem of the South Platte River, and the <br />alluvial aquifer in the Lost Creek and Kiowa-Bijou Designated Basins) there has been little to no <br />change in water levels over time. This is suggested by the large number of monitoring locations <br />that show less than a foot change in water levels (Figure 10). The second observed trend occurs <br />in the Cache la Poudre River and Upper Black Squirrel Creek Designated Basin. In these <br />locations there have been both increases and decreases in the water levels in wells located in <br />close proximity to each other over the 20 to 30 year time period (Figure 10). The variability of <br />water level trends in these areas are likely due to the localized effects of pumping and recharge. <br />The third observed trend is where water levels have shown consistent declined based on the <br />spring measurements. This includes wells located along the lower portion of Box Elder Creek <br />and the downstream (northern) portion of Bijou Creek in the Kiowa-Bijou Designated Basin. <br />The water level declines in these areas are likely a result localized pumping. <br />3.3 Hydrographs <br />Water level trends over hme at individual wells were used to create hydrographs for 24 wells <br />located throughout the South Platte Alluvium Region. Wells were selected based upon the <br />period of record available, existence of recent data, and spatial distribution. The wells selected <br />are spatially distributed throughout the South Platte Alluvium Region as shown in Figure 11. <br />Hydrographs for the 24 wells in the South Platte Alluvial Region are shown in Figures 12 to 17. <br />Based on analysis of the individual well hydrographs, the water levels in the mainstem of the <br />South Platte Alluvium Region generally appear to have remained stable over time, with water <br />levels changing by less than 5 feet in 14 of the 20 wells shown in Figures 12 to 17. Water levels in <br />most wells, however, do show the effects of localized pumping. <br />Two of the wells shown (designated as wells 1268 and 1238 and shown on Figures 13 and 17, <br />respectively) do show approximately 25-foot declines in water levels over the period of record. <br />These wells are located in eastern Weld and Morgan Counties, respectively, and are located <br />near wells for which other hydrographs do not show long-term declining trends. It is possible <br />that these water levels are influenced by pumping from nearby wells. <br />4.0 Summary and Conclusions <br />CDM has completed SPDSS Task 44.3: the collection, analysis, and mapping of water level data <br />for the South Platte Alluvium Region. The purpose of this task was to examine the sources and <br />types of data available in the region, perform the data processing to allow it to be internally <br />consistent and HydroBase-compatible, and provide data useful in the support of upcoming <br />groundwater modeling. <br />Below are conclusions from the completion of these tasks. <br />SPDSS Phase 3 Task 44.3 TM -Final 14 <br />11/29/2006 <br />