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~ ~~~ <br />Approach: <br />93.1 Historic Aerial Photography and Satellite Imaigery Search.. Conduct an extensive search for <br />historic satellite imagery, aerial photographs, historic land use maps, and reference data for use in <br />this task. Research conducted during the SPDSS feasibility study indicated that satellite imagery <br />from the 1970s and 1980s was available, and 195Os aerial photographs were reportedly available <br />with the USGS and University of Colorado and other sources such as the USDA, although the full <br />extent of these 1950s data has yet to be determined. 1930s hand drawn maps for the South Platte. <br />River basin also are available with Division 1. Assess the availability and quality of these <br />photographs for historic mapping and evaluate the quality and availability of multispectral Landsat <br />TM and MSS satellite imagery. Prepare a list of recommended satellite, maps, and aerial <br />photography for acquisition, to be purchased under Subtasks 93.2, 93.3, and 93.4. Conduct <br />discussions with the State and make recommendations on data to be acquired. <br />93.2 Mapping of Historic Land Use for the 1980s. Obtain 1980s land use maps, aerial photographs, <br />and 1980s agricultural statistics (from the CU Contractor) to be used for reference. In addition, the <br />Contractor will obtain a series of digital Landsat TM satellite images for the study area for a <br />cropping season in the 1980s, preferably during the; period 1986 to 1989 because of the availability <br />of USGS digital orthophoto and/or high quality Laaidsat Thematic Mapper data. Five image frames <br />will be obtained for the study area and five dates of imagery for each image frame are anticipated to <br />be acquired for different dates during the growing seasono Data will be georeferenced, corrected for <br />atmosphere and other influences, and analyzed to estimate irrigated lands and crop types for one <br />representative year in the 1980s. The analysis will use the same multitemporal analysis techniques <br />developed for the 2001 land use and irrigated parcel boundary mapping (SPDSS Memorandum 89.1, <br />July 2003). In addition, relevant elements of Decision Tree classification algorithms, a refinement of <br />classification methods being. used in Phase 1 and. 2, will be applied. The irrigated parcels and <br />mapping from 2001 as well as the parcels from the 1950s and 1970s will be used as reference <br />93.3 Mapping of Historic Land Use for the 1970s. Obtain 1970s land use data including satellite <br />imagery, land use maps, and agricultural statistics .(from the CU Contractor). Obtain a series of <br />digital Landsat MSS satellite images for the study area for a cropping season in the late 1970s. <br />Landsat MSS images have only four bands of data and an 80m-pixel size, compared with seven <br />bands and 30m for the Landsat TM data used for 2001 classification and proposed for the 1980s <br />mapping. Thus, the 1970s mapping likely will not be as accurate as that for the 1980s and for 2001. <br />Five image frames will be obtained for the study area and, preferably, four to five dates of imagery <br />for each frame acquired from different dates during the growing season. Data will be georeferenced, <br />corrected for atmosphere and other ,influences, and analyzed to estimate irrigated lands and crop <br />types for one representative year in the 1970s. The analysis will use a multitemporal analysis <br />techniques similar to those used for the 2001 lands use and irrigated field boundaries mapping <br />(SPDSS Memorandum 89.1, July 2003). The irrigated parcels and mapping from 2001 as well as the <br />parcels from the 1950s and 1980s will be used as reference. <br />93.4 Mapping of Historic Land Use for the 1950s. Obtain data applicable to land use in the 1950s <br />including aerial photographs, historic maps, and a€;ricultural statistics from the period. The aerial <br />photographs will be visually interpreted using irrigated parcel boundaries from 2001, 1980s and <br />1970s as reference. Digital scanning and georefere:ncing of the 1950s aerial photographs likely will <br />be performed as necessary. Detailed crop type mapping will not be possible from the historic photos. <br />However, it is anticipated that general cropping patterns (i.e. hay/pasture vs. row crops) will be <br />estimated from the photo interpretation and further segregated using land use mapping from more <br />recent years, agricultural statistics, and other information. <br />93.5 Assignment of Water Supply for 3 Dates Historic Land Use. The source of water for each of the <br />irrigated parcels mapped for'each of the periods will be determined and attributed accordingly. It is <br />expected that the water supply source identified for the 2001 mapping, to be completed under Task <br />7 <br />