The San Juan Recovery Implementation Program (SJRIP) Hydrology Committee provides oversight regarding hydrologic data and models used to SJRIP. A hydrologic data set, models, and rulesets have been developed. Collectively, these are called the San Juan Basin Hydrology Model (SJBHM). The models are primarily used to develop and test Navajo Reservoir operating rules that facilitated compliance with the flow recommendations of the SJRIP. The SJBHM was also used to simulate and assess the impacts of various levels of water development or depletion scenarios on stream flows and determine if the flow criteria could be met with a given level of development. The hydrology model was developed using RiverWare, a generic model and ruleset building tool developed by the Center for Advanced Decision Support for Water and Environmental Sciences(CADSWES) at the University of Colorado.
The Bureau of Reclamation (Reclamation) is primarily responsible for SJBHM. The SJBHM is the third generation of evolution. The first two generations used hydrology data developed by Reclamation for the time period of 1970 to 1993 and extended historically to 1929 by Keller-Bliesner Engineering using Colorado River Simulation System hydrology data. The third generation uses Colorado Decision Support System (CDSS) hydrology data. The third generation is under development and is anticipated to be completed by June, 2003. An inventory of models and rulesets is available as well as a log that documents model and ruleset development. In addition, links are provided to all hydrology data and model documentation.
San Juan Basin Background
The San Juan River Basin drains an area of approximately 25,000 square miles, an area equal to that of West Virginia. About 39 percent of the drainage is in New Mexico, 23 percent in Colorado, 20 percent in Arizona, and 17 percent in Utah. The San Juan River is the second largest tributary to the Colorado River. Its source is on the Continental Divide in southern Colorado, and it flows approximately 350 river miles westerly to its confluence with Lake Powell.
Elevations vary from about 3,700 feet above sea level at the confluence with Lake Powell to over 14,000 feet on the crests of mountain peaks in the San Juan range. Precipitation varies from more than 60 inches annually in small areas along the high peaks, to less than 10 inches in extensive parts of the Basin, to less than one-tenth inch in others.
San Juan Recovery Implementation Program Background
The purpose of the San Juan River Basin Recovery Implementation Program (Program) is to protect and recover endangered fishes in the San Juan River basin while water development proceeds in compliance with all applicable Federal and State laws. Endangered species include the Pikeminnow (formerly known as the Colorado Squawfish), or Ptychocheilus Lucius, and the Razorback Sucker, or Xyrauchen Texanus. It is anticipated that actions taken under this Program also will provide benefits to other native fishes in the basin and prevent them from becoming endangered in the future.
Last Revised: 3/1/2005