URGWOM SUMMARY

The Upper Rio Grande Water Operations Model (URGWOM) is a computational model developed through an interagency effort and is used to simulate processes and operations of facilities in the Rio Grande Basin in New Mexico from the Colorado state-line to El Paso, Texas (flood control operations only below Caballo Dam) and complete accounting calculations for tracking the delivery of water allocated to specific users. Policy for setting dam releases along with diversions and other demands are represented in coded rules in an URGWOM ruleset. Various methods are included to represent processes such as floodwave travel times; reservoir evaporation and seepage; conveyance losses to deep percolation, evaporation, and transpiration; surface water-groundwater interaction; and irrigation return flows. Simulations may be completed for a given hydrology using either inputs for operations of facilities in the Basin or using the ruleset for the operation policy. Note that URGWOM is NOT a water supply model, a climate model, a water rights model, a rainfall/runoff model, a hydraulic model, or a groundwater model; although, such models may be used as pre-processors or post-processors with URGWOM to complete evaluations for a broader range of indicators.

Four separate URGWOM modules are utilized for modeling exercises and decision support: Planning, Water Operations, Forecast, and Accounting. The Planning Model is used to complete daily timestep rulebased simulations for different operation scenarios to evaluate subsequent long-term impacts of a proposed action on various indicators including deliveries to water users, river flows, interstate Compact deliveries and Compact status, and the overall water budget. Studies may entail completing a model run with a baseline model and ruleset and comparing results to output from an alternate simulation completed with a proposed change to policy for operating a specific facility. Model runs may be completed using historical hydrology or synthetic hydrologic sequences developed with reference to paleo-data.

The Water Operations Model is used to complete daily timestep rulebased simulations to forecast operations, deliveries, and resulting flows through the end of a calendar year with forecasted inflows computed using the Forecast Model. Inputs on conditions year-to-date are provided from the Accounting Model (Refer to the schematic to the right depicting the linkage between the different modules utilizing the data management interface (DMI) in the RiverWare software package discussed further below). The Water Operations Model is used for determining forecasted flows and reservoir storage for Annual Operating Plans (AOP). This ability to forecast water operations results in reduced waste, elimination of unnecessary reservoir spills, prevention of unwanted downstream flooding, and more equitable distribution of available water supplies. Simulations with the Water Operations Model are completed after the first day of each month from February through May after current forecasted runoff information is provided by the Natural Resources Conservation Service (NRCS) and National Weather Service (NWS) which is processed with the Forecast Model. (Accounting is included in URGWOM for tracking ownership of water and primarily to track water allocated for several contractors for San Juan-Chama Project water. Several of the accounts for San Juan-Chama Project water were combined into one account in the Planning Model to simplify accounting calculations for long-term planning studies, but otherwise, the Planning Model and Water Operations Model are the same.)

The Accounting Model is utilized to simulate year-to-date conditions in the Basin and provide an updated status of account storage and deliveries made to water users. Accounting Model simulations are completed using inputs for actual operations and thus do not involve using rules. Information from the Accounting Model is used to generate reports to document the status of storage in accounts.

URGWOM improves information sharing as updates on the storage in accounts is computerized and plots of predicted operations and conditions in the Basin are digital and can easily be prepared and disseminated to interested parties. URGWOM functions as a central repository for information on system status, characteristics, and projected operations.

As the plan for URGWOM development was first being created, different software options to use for URGWOM were reviewed. After an initial review of several reservoir and river simulation software packages along with the needs for an Upper Rio Grande Water Operation Model, RiverWare was selected as the software package for URGWOM. A key benefit of RiverWare is that software development is ongoing and new methods and capabilities can be added to RiverWare by the software developers to meet the evolving needs for URGWOM. RiverWare was developed by the Center for Advanced Decision Support for Water and Environmental Systems (CADSWES) at the University of Colorado at Boulder. Software development continues to be sponsored and supported by the Tennessee Valley Authority (TVA), Bureau of Reclamation (Reclamation), and Corps of Engineers (Corps). RiverWare is a generalized river basin modeling environment that can be used to develop an operations model for any configuration and to simulate operations to meet needs for flood control, water supply, recreation, water quality, and navigation. RiverWare is designed to provide river basin managers with a tool for scheduling, forecasting, and planning reservoir operations and includes extensive capabilities for rulebased simulations and water accounting. Efforts are underway to integrate RiverWare into the Corps Water Management System (CWMS). RiverWare is a licensed software package that can be obtained for a fee and training courses are available. A free RiverWare viewer is available that can be obtained to view models but cannot be used to complete runs or modify model files. For more detailed information about RiverWare, visit the CADSWES RiverWare web page at http://cadswes.colorado.edu/riverware/.