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<br />Task 10 - Data Extension Needs and Evaluation <br /> <br />Responsibility: Boyle <br /> <br />Objective: To enhance the Water Resource Planning models, the State is interested in developing a <br />longer period of record. Investigation of options for extending the data and developing an approach <br />will be performed in this task. <br /> <br />Approach: <br /> <br />10.1. Define CRDSS Needs In this subtask, the need for developing a longer period of record for <br />the water Resource Planning Model will be determined. This task would include the <br />following: <br /> <br />10.1.1. Become familiar with the CRDSS Water Resource Planning Model and CD Model <br />structures and operations. This would include review ofthe general framework ofthe <br />models, the model structures, the data input requirements, the operational limitations <br />and the sensitivity of the model results to various input data. The focus will be on the <br />time series data requirements. <br /> <br />10.1.2. Review the historic and/or synthetic Period of Record used in past studies within and <br />near Colorado. Describe techniques used, if any, to select a study period and extend <br />records. Discuss the approach taken, if any, to remove mans impact on gage records <br />(natural stream flow estimates versus gage records) before data extension. <br /> <br />10.1.3. Interview CRDSS, CWCB and up to two Technical Advisory Committee members <br />regarding the need for and use of an extended period of record for the Water <br />Resource Planning Model. Describe by example the potential use of a design <br />drought sequence for analyses by a Water Resource Planning Model. A design <br />drought is similar in concept to a design storm used in flood analyses, but deals with <br />the extremes of water shortage rather than water excess. Through analyses of historic <br />data and stochastically generated of flow data a sequence of flows are developed <br />which represent droughts of specific return periods, for example, the drought <br />expected on the average once every fifty years or once every 100 years. Often these <br />drought flow sequences extend from one to ten years or more depending on the <br />return period. They are typically bounded by a longer flow pattern that allows a <br />ramping into and out of the actual drought. This period of twenty to thirty years may <br />then become a standard sequence that is used to evaluate and compare alternative <br />management scenarios. <br /> <br />10.1.4. Prepare a draft memorandum describing the results of this task. The memorandum is <br />expected to contain approximately 5 pages of text. <br /> <br />10.1.5. Incorporate State comments into a final memorandum. <br /> <br />10.2. Evaluate Extension of Historic Data Based on the goals of the data extension identified in <br />previous Tasks, regression techniques or models will then be reviewed to determine which <br />method can be employed to meet the CRDSS Water Resource Planning Model requirements. <br />This subtask would include the following: <br /> <br />C:\w\crdss\scope\boy II Ib\crdss3 .doc <br /> <br />0344 <br /> <br />5/30/97. Page 13 <br />