Laserfiche WebLink
<br />description of the probable future water levels in the aquifers but do not address the <br />e problem of water levels in the pumping wells. Methods to estimate pumping water <br />levels based on simulated regional water levels exist for certain aquifer conditions, but <br />do not properly account for changing aquifer thickness as the aquifers are drained. <br />HRS has developed a method of simulating pumping water levels in the type of wells <br />found in the Denver Basin and applied this methodology to this problem. <br /> <br />2.0 Hydrogeologic Framework <br /> <br />e <br /> <br />In ascending order the Denver Basin aquifers include the Laramie-Fox Hills, <br />Arapahoe, Denver and Dawson aquifers. The Laramie Formation is between the <br />Arapahoe and Laramie-Fox Hills aquifers and the Pierre Formation lies below the <br />Laramie-Fox Hills aquifer. These four sedimentary aquifers were developed through <br />the formation of the structural Denver Basin and were deposited through sea <br />regressions and mountain building. The Denver groundwater basin underlies <br />approximately 6,700 square miles. It extends from Greeley in the north to Colorado <br />Springs in the south and from the Front Range in the west to the high plains in the east. <br />Figure 2.1 shows the general location of the Denver Basin aquifers and their outcrop <br />areas. Figure 2.2 is a north-south cross section through the aquifers showing their <br />relative thickness and depth below ground surface. <br /> <br />. <br /> <br />The Laramie-Fox Hills aquifer consists of a sequence of sandy shales inter <br />bedded with thin sandstone layers near its base and thick sandstone layers near the <br />top. Thickness of the sequence ranges from thin outcrop areas to about 200 feet. In <br />Phase 1 of this study the decision was made not to analyze the Laramie-Fox Hills <br />aquifer due to budget limitations. The Arapahoe aquifer can be SOO to 600 1eet thick <br />within the central portions of the basin. The Arapahoe aquifer material consists of <br />conglomerate and sandstone inter bedded with clay layers. The upper portion of the <br />Arapahoe aquifer is finer grained than the basal portion. The Colorado Division of <br />Water Resources divided the Arapahoe aquifer into Upper and Lower aquifers north of <br />Township 6 South. The Denver aquifer consists of a series of poorly-bedded to <br /> <br />3 <br />