Laserfiche WebLink
and water table. In these cases the data used to develop contours is not provided in the <br />individual reports. <br />Table 1: Summary of Data Sources and Type of Data Provided <br />Data Source Number of Picks Contours <br />B~orklund and Brown (1957) 412 Yes <br />Duke et al. (1966) 0 Yes <br />Erker et al. (1967) 0 Yes <br />Hurr and Schneider (1977) 0 Yes <br />Hurr and Schneider (1972a -1972f) 0 Yes <br />NHPQ (1967) 0 Yes <br />Robson (1996) 0 Yes <br />Robson et al. (2000a - 2000d) 0 Yes <br />Smith et al. (1964) 1,072 Yes <br />SPDSS Task 35 19 No <br />SPDSS Task 42 0 Yes <br />DW R 266 No <br />Weist (1964) 1 No <br />Willard Owens Associates (1971) 0 Yes <br />Total 1,770 <br />1.2 Data Analysis and Processing <br />1.2.1 Processing of Historical Bottom of Alluvium and Groundwater Level Contours <br />Two of the bottom-of-alluvium and groundwater level contour maps were available in <br />electronic format, while the others were available only in hard copy format. Electronic contour <br />maps were obtained from Robson, S.G., (1996) and Robson et al. (2000a to 2000d), while hard <br />copy contour maps were obtained from Bjorklund and Brown (1957), Duke et al. (1966), Erker et <br />al. (1967), Hurr and Schneider (1972a -1972f, 1977), NHPQ (1967), Smith et al. (1964), and <br />Willard Owens Associates (1971). To convert the hard copy maps into a digital format, the <br />bottom of alluvium and groundwater level contour maps were scanned, georeferenced, and <br />then digitized to develop a series of electronic polyline contour maps for the South Platte <br />Alluvium Region. In addition to bottom of alluvium and groundwater level contours, Bjorklund <br />and Brown (1957), Duke et al. (1966), Erker et al. (1967), Hurr and Schneider (1972a -1972f, <br />1977), and NHPQ (1967) presented the extent of saturated thickness within their study area. The <br />lines of 0 saturated thickness were also digitized. <br />Distortion of the data may be introduced in the georeferencing process. Imperfections in <br />georeferencing are created because the hard copy maps are often folded, stretched, and <br />sometimes drawn on low resolution base maps, which prevent a perfect matching of map <br />points to real world points on a regional scale. However, the georeferencing is sufficiently <br />accurate for the purposes of this TM. <br />SPDSS Phase 3 Task 42.3 TM -Final <br />11/30/2006 <br />