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Sanitation District (PWSD), where no pumping records were submitted, the decree information <br />submitted was used to estimate monthly usage. In this case, the monthly rate was used to <br />estimate the annual appropriation amount. <br />2.2 Pumping Duration <br />As shown in Table 2, the entities that submitted data generally provided pumping records <br />through 2005, the last year for which a full year of data were available. For the entities that did <br />not supply pumping records through 2005, the trend from the most recent years of data is used <br />to extend the data through 2005 so there would be a consistent period of record for all entities <br />evaluated in this task. <br />Most of the data and pumping records received by CDM did not contain information regarding <br />the date when pumping at each well began. In several cases, such as Northern Colorado Water <br />Association (NCWA), Centennial Water and Sanitation District (CWSD), East Cherry Creek <br />Valley (ECCV), and Greeley, representatives from the water user verbally provided information <br />as to the date when the wells came online. For all other entities, the appropriation date listed in <br />HydroBase was used to estimate the date that wells began pumping. Based on the time <br />necessary for well drilling, construction and connection to water distribution lines, it was <br />assumed that pumping started approximately one year after the appropriation date if no other <br />information was available. <br />2.3 Filling of Missing Pumping Records <br />The data formats, types of information and period of record for the historic pumping data <br />varied greatly among the M &I entities so a variety approaches were needed to fill the missing <br />pumping records. This section begins with a discussion of the general approaches used to fill <br />missing data records and is followed by a description of specific approaches applied to each <br />entity. <br />General Approach <br />During the period of time when historic pumping records were not available, several <br />approaches were used to estimate M &I pumping. This process required a customized <br />approach for almost each entity that provided historic records, utilizing the various available <br />data sets and other sources of information. These processes and steps taken to fill missing <br />records are summarized in the following section. Details for how missing records were filled <br />for each entity are provided in Appendix A. <br />Pumping records provided in a weekly and monthly format were summed to annual amounts <br />and plotted to determine if a temporal correlation and trend existed between annual pumping <br />and time. Population data for a given entity were also plotted against yearly pumping and <br />time. If a relationship (R > 0.70) occurred between population and pumping, a regression <br />equation was used to estimate rates for missing years of pumping records. For example, a good <br />correlation occurred between Brighton's pumping and population data. In most cases, there <br />was no correlation or trend between these variables and so the average per capita consumption <br />value computed for each county in the South Platte Basin based on year 2000 information was <br />used to relate pumping to historic population. Population data was on a decadal basis, <br />obtained from the US Census Bureau and daily per capita water usage (GPCD)) was obtained <br />from Appendix E of the Colorado Statewide Water Supply Initiative Report (SWSI; CDM, 2004). <br />SPDSS Phase 3 Task 41 TM -Final <br />02/08/2007 <br />