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<br />001941 <br /> <br />is not backwards compatible with previous releases. A 2.1 compatible version of the model should be <br />available during the summer of 1999. <br /> <br />A key, but external component of the San Juan Model is a set of Excel spreadsheets and BASIC <br />programs. This is the post-processor. The Model operates on a monthly time step, Daily flow data <br />are required to determine if the fish habitat flow criteria are being met, The daily flows required for <br />this assessment result from post-processing with the mentioned tools after completion of each model <br />run. This is discussed more fully in the Analysis of Model Output section at the end of this <br />document. <br /> <br />Natural flows and Historic Deoletions <br /> <br />The San Juan RIP Hydrology Model begins with estimates of naturnl flows for the various river subbasins <br />contributing to the San Juan River. Natural flows are computed by taking United States Geological <br />Survey (USGS) gaged stream flows at available stations throughout the river basin and adjusting them for <br />man-made influences, These man-made influences may include depletion of water through consumptive <br />use, diversion of water to other basins, import of water from other basins, and evaporation from man <br />created open water surfaces such as reservoirs, The model and naturnl flows are then validated when the <br />gauged flows are reproduced by entering the historic operation used to derive the naturnl flows, <br /> <br />Model Validation and Calibration <br /> <br />Two other models beside the SJRIP hydrology model used in its development of. These are the <br />Validation model and the Calibration model. The Validation model consists of actual or "hardwired" <br />historical depletions and reservoir releases, The purpose of this model was to determine if the <br />configuration was correct by using natural flows and reproducing gage flows after accounting for <br />man's influence on the basin, There are no operating rules involved in the validation model. <br /> <br />Once a correct model configuration was produced, operating rules were added to simulate operation <br />of various projects such as the San-Juan Chama, Pine River, and the major reservoirs. This model <br />with operation rules is the Calibration model. It is essentially a platform for rule development and <br />testing to verify that all facilities (except Navajo Reservoir) are operating consistent with historic <br />practices. Because of the complexity of the simulation of historic Navajo operating, rule was not <br />calibrated, Rules are calibrated by attempting to reproduce the depletions and shortages calculated in <br />the original Bureau of Reclamation natural flow study, <br /> <br />Qoeratina Rules <br /> <br />Operation rules are what make the San Juan Model more than just a simple volume balance model. Rules <br />are added to make decisions within the model. For example, rules are used to forecast reservoir inflow <br />and determine when fish releases are made. In RiverWare versions prior to 2, rules were implemented in <br />a script language called TCL, In version 2 and later a new function based rule language was <br />implemented, Because of the change in rule language, Riverware 2,1 is not compatible with previous <br />versions, <br /> <br />DRAFT - SJRIP Hydrology Model Documentation <br />June 18, 1999 <br /> <br />2 <br />