Laserfiche WebLink
0 <br />WATER LEVELS IN THE DENVER BASIN BEDROCK AQUIFERS <br />. SPRING 1993 <br />Purpose <br />The purpose of this report is to provide water -level measurements taken in the Denver Basin <br />bedrock aquifers prior to spring 1988, measurements taken after 1988, and water -level change <br />data for the periods spring 1992 - spring 1993, and spring 1988 - spring 1993. The aquifers of <br />investigation are the Dawson, Denver, Arapahoe, and Laramie -Fox Hills. The spring 1993 data <br />for each aquifer have been contoured and are presented in four potentiometric-surface maps. <br />The spring 1988 - spring 1993 water -level change data has been utilized in a water -level decline <br />map of each aquifer. A number of hydrographs of representative wells accompanies the maps. <br />The water -level decline maps were prepared by plotting the 1988-1993 water -level change for <br />each aquifer. The data were then isolated according to range of decline. For example, all water - <br />level declines within the range of 50-100 feet lie within a 50-100 feet decline area. In most areas <br />the water -level decline range is 0-50 feet with local water -level rises. The line which separates <br />each decline area does not represent a true contour. It is a line intended to separate water -level <br />declines which fall within the chosen range irrespective of position within the decline area. Since <br />the location of each line is highly subjective, it is suggested that investigators using this report <br />rely heavily upon the data. <br />The following paragraphs describe the general characteristics of each map and includes a <br />hydrogeologic interpretation if feasible. Figure 1 shows the Denver Basin observation well <br />network for spring 1993. Figures 2, 4, 6, and 8 are potentiometric surface maps, and figures 3, <br />5, 7, and 9 are water -level decline maps for the period 1988-1993. <br />General Interpretation <br />Dawson Aquifer - The shape and configuration of the Dawson aquifer potentiometric surface <br />is shown in figure 2. A significant groundwater high is present in the Black Forest area and <br />groundwater slopes radially outward from it. Groundwater troughs or lows occur in southern and <br />southeastern metro Denver, and just west of the community of Black Forest. The troughs are <br />attributed to relatively continuous pumping of wells operated by water and sanitation districts. <br />The groundwater ridge which extends northeastward from Black Forest is probably a remnant <br />of the pre -development potentiometric surface. <br />The Dawson water -level decline map (fig. 3) shows that throughout most of the extent of the <br />Dawson aquifer, water -level declines during the period 1988-1993 lie within the 0-50 feet range. <br />Declines ranging from 25 to 100 feet generally occur in the Castle Rock -Fran ktown-Parker area <br />and are attributable to withdrawals for municipal purposes. Examination of the data reveals that <br />at some isolated sites the water -level has risen since 1988. <br />Denver Aquifer - The potentiometric surface map of the Denver aquifer (fig. 4) is typical in that <br />a significant groundwater high occurs in the Black Forest area and groundwater troughs or lows <br />occur in areas of significant drawdown. The latter occur in south metro Denver, the Castle Rock <br />area, and the Air Force Academy area (fig. 5). Water -level declines in outlying areas lie within <br />the 0-50 feet range with local water -level rises. <br />0 - 1 - <br />