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.. ! • <br />will be generated and incorporated into the appropriate appendices. After resolving PRC <br />comments, final versions of each appendix will be prepared. <br />The TM for this task will document all data, procedures and tools necessary to create the model <br />files, and all files will be included in electronic format. It is anticipated that the draft TM for this <br />task will be submitted to the State approximately 4 months after State approval of the Phase 3 <br />model and that the final TM will be ready approximately 7 months after State approval of the <br />Phase 3 model. <br />Task 48.2 Develop Calibration Targets and Criteria <br />• The approach to calibration will be defined as the initial step. This approach will include a <br />combination of manual methods and automated parameter estimation methods including <br />potential use of pilot points and regularization. Specific goals for the calibration will be <br />identified in terms of quantitative error measures; however, it is anticipated that the specific <br />calibration goals will be the following parameters and approximate ranges listed: <br />o The absolute value of the mean difference between modeled and observed heads <br />(groundwater levels) across all time periods will be less than 5 feet. <br />o The absolute value of the difference between observed heads across all time periods <br />will be Less than 5 feet for 75 percent of the observations. <br />o Observed and calculated average annual flaws will be within 10 percent for each <br />component greater than 25,000 of/yr. <br />o Residuals for flow and head will be randomly distributed on a geographic and <br />temporal basis. <br />The methods by which calibration will be defined will be described. These methods will be in <br />conformance with ASTM D 5490-93 Standard Guide for Comparing Groundwater Flow <br />Model Simulations to Site-Specific Information and with the more general guidance presented <br />in the standard textbook Applied Groundwater Modeling (Anderson and Woessner, 1992). <br />The calibration will compare calculated flows and water levels with calibration targets using <br />quantitative methods to describe the goodness of fit between observed and modeled values. <br />• The water level and stream flow calibration targets will be imported into the modeling GIS <br />repository from download of the appropriate data in HydroBase for use during the calibration <br />process. Tools developed under Task 50 will be used to migrate the target data into GMS and <br />other DMIs for evaluation of calibration. <br />• All available water level and appropriate stream flow observations will be used as calibration <br />targets. Use of all available data may result in some increased `noise' in the calibration target <br />data set and calibration statistics due to the variable quality of data that are available and <br />presence of data outliers, so certain data maybe removed from the target data set or given a <br />low weighting value during the calibration process. These data have been compiled during <br />earlier phases and are available in HydroBase. These calibration targets will be used to assess <br />the ability of the model to reproduce field observations. Since calibration to temporal <br />SPDSS_Phase4~w_SOW_09-IS-06.doc j j <br />