Documentation

Assumptions, methods, and data used in URGWOM to simulate the Rio Grande hydrology, water accounting, and system operations are described in the DRAFT documents available through the links below. Documentation is currently being updated to reflect several recent changes, most notably the Middle Valley upgrade. The provided documents should be considered working documents.

Methods included in URGWOM and policies reflected in rules and accounting were developed using the best available data and information. Lack of adequate data or poor data for many areas in the system preclude the ability to develop completely precise, reliable methods for the many physical processes affecting the water supply in the Basin. In these cases, the best available data were utilized to develop the most accurate tool possible in URGWOM. In some cases, data extrapolations were required because of a lack of data. One benefit of the continued development and improvement of URGWOM is that additional data needs are identified for areas in the system where additional data would result an even better understanding of the system.

Use of data and relationships developed for URGWOM should be done appropriately and with proper consideration for all assumptions employed for method development. For example, care should be exercised in the application involving high or low-flow extremes. For example, see Graph 145 in the appendix PHYGRAPH file. In this instance, the lack of reliable low-flow measurement data has resulted in computed travel times varying between 25 hours and 60 hours for the flow of 300 cfs.

1. Physical Model

• Physical Model Documentation - Third Technical Review Committee Draft ( PHYMOD) (pdf file, 2.4 MB)


• Physical Model Appendix (PHYGRAPH) (pdf file, 1.8 MB)

Documentation of the physical model is currently being revised to reflect the significant changes for the Middle Valley Upgrade; however, information pertaining to the model setup for areas other than the Middle Valley (including discussion of river routing and the methods and assumptions used to develop loss coefficients) is accurate and available through the link below. Please refer to this report in the interim while a full revision is being developed.

2. Planning Model.

• Base Run Start-up and Initial Conditions Assumptions ( START-UP) (pdf file, 380 kB)

Assumptions required to start up the Planning Model are described in this START-UP document. Hydrologic adjustments made to adapt the Water Operation Model for planning studies are also described. Note that user manuals for the Planning Model and Water Operations Model are currently being developed.

3. Accounting Model

• URGWOM Physical Accounting Model Documentation (PHYACCT) (pdf file, 351 kB)

This document includes descriptions of the accounting methods set up in RiverWare specifically for URGWOM used to apportion losses in Rio Chama and mainstem reservoirs between San Juan-Chama Project water and native Rio Grande water. Details of operations, physical loss, and net loss computations are included for each reservoir along with the details for representing the effects of sediment deposition. Accounting in URGWOM using the methods described in this document replaces the FORTRAN daily water accounting programs previously used by Reclamation to track the delivery, use, and storage of San Juan-Chama Project water in the Basin.

• Physical Accounting - Abiquiu Reservoir Accounting Example (EXACCT) (pdf file, 142 kB)

This Physical Accounting (EXACCT) document provides a step-by-step example computation of daily accounting of reservoir losses at Abiquiu Reservoir.

• Accounting Model Validation (WTRACCT) (pdf file, 187 kB)

The discussion in this Accounting Model Validation (WTRACCT) document describes the procedures used to validate the accounting for the six reservoirs used in URGWOM: Heron, El Vado, Abiquiu, Cochiti, Jemez Canyon, and Elephant Butte. The validation process involved evaluating the difference between the computation of data parameters (daily storage) using URGWOM, which uses RiverWare as its platform, and values obtained using the FORTRAN daily programs.

4. Forecast Model.

• URGWOM Runoff Forecast Model Documentation (FORECST) (pdf file, 1.84 MB)

This document includes a description of the Forecast Model designed to develop snowmelt runoff hydrographs for portions of the Basin. These hydrographs are based on March-July volumetric forecasts developed by the Natural Resources Conservation Service (NRCS) and the National Weather Service (NWS) for various points in the Basin. These snowmelt runoff hydrographs are primarily used as inputs to the Water Operations Model for projecting future operations and preparing Annual Operating Plans (AOP). Other parameters needed to run the Accounting Model and Water Operations Model that are not available real-time or must be forecasted into the future are also generated in the Forecast Model.

5. Rules

As a result of a better understanding of potential agreements and actions in the Basin along with changes to improve the efficiency for modeling, significant changes have recently been made to the URGWOM ruleset used to set deliveries and demands in the Basin and represent policy for operating all the facilities in the system. Rules documentation is currently being updated.