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<br />4. Draft and final Review of Other Methods memorandum. <br /> <br />5. Recommended data extension approach. As appropriate, revised Task 11, Task 12, schedule, <br />and budget for implementing recommended method of data extension. <br /> <br />Task 11 - Historic Data Extension <br /> <br />Responsibility: Boyle <br /> <br />Objective: To develop and implement an extended historic data base for the CRDSS Water <br />Resource Planning Models for use in simulations and analyses. It is anticipated that this data base <br />will extend the current 17 year (1975-1991) period of record on the order of an additional 50 years. <br /> <br />Approach: <br /> <br />11.1.Data Development The CRDSS database contains the historic period ofrecord for <br />streamflow, diversion, evaporation, temperature, and precipitation data that are required for this <br />study. Unfortunately, some reservoir end-of-month content data may not be digitized for the <br />period of record and most diversion data is only digitized from 1975 forward. In this subtask, <br />missing reservoir end-of-month content data will be collected and missing diversion data <br />estimated for the selected study period prior to 1975. The existing CRDSS database will be <br />reviewed for reservoir end-of-month content data for the 20+/- reservoirs explicitly modeled in <br />Phase IlIa. Missing, non digitized reservoir end-of-month content data will be obtained from <br />published reports or owners and digitized in a format suitable for inclusion into the CRDSS <br />database by the State or other contractor. Historic non digitized diversion data prior to 1975 will <br />be identified from the CRDSS database. Missing data will be estimated for each of the 5 <br />CRDSS Water Resource Planning models by developing a simple program and input data which <br />performs the following: <br /> <br />. Reads the historic diversion data files developed for StateMod in Phase IlIa <br />. Reads a file which contains: (I) An average, wet or dry runoff type year indicator <br />for each year prior to 1975 in the study period based on a representative streamflow <br />gage in each basin. (2) Up to 5 sets of representative diversion years which <br />correspond to a typical wet, dry or average year in that basin. The first set of <br />representative diversion years will be the default applied to most structures. The <br />remaining 4 will be available for structures that require special treatment. (3) A <br />listing of structures that use the non default representative diversion year data. <br />Estimates diversions for the selected study period prior to 1975 based the type of <br />runoff year (wet, dry, or average). Includes a method to account for structures which <br />are known to have not diverted prior to 1975. <br /> <br />11.2.Develop Natural Flows In this subtask natural flows will be developed at all stream gages <br />currently contained in the Phase IlIa Water Resource Planning models (approximately 180 <br />gages). Natural flows will be developed by executing the appropriate CRDSS Data <br />Management Interfaces in order to develop the data required to operate the baseflow component <br />of StateMod. Key input to this process will include: gaged streamflows, historic or estimated <br />diversions, historic or estimated reservoir end-of-month contents, and Phase IlIa diversion <br />efficiency and return flow properties (timing and location). If necessary, the State will be <br />responsible for performing any upgrades to the StateMod baseflow component to allow missing <br /> <br />0341 <br /> <br />. <br /> <br />C :\w\crdss\scope\boy IIIb\crdss3 .doc <br /> <br />5/30/97 - Page 16 <br />