The URGWOM Documentation volumes are listed below, followed by a brief description of each document:

Volume 1: Physical Documentation

Volume 2a: Policy Rules Documentation

Volume 2b: Initialization Rules Documentation

Volume 2c: Expression Slot Functions Documentation

Volume 3: Accounting Concepts and Methods

Volume 4: Database Documentation

Volume 5: DMI and SCT Documentation

Volume 6: Script Documentation (User's Manual)

Appendices :  **Appendix A-D located in Volume 2a

Rules Documentation Appendix E

Rules Documentation Appendix F

Rules Documentation Appendix G

Rules Documentation Appendix H

1. Physical Documentation

Volume 1 describes the hydrology of the Rio Grande and discusses how natural processes, human manipulation (operations) of the river, and laws related to human manipulation of the river is simulated using URGWOM. It includes a description of the physical features of streams, canals, drains, reservoirs, and aquifers; physical constants (e.g., loss coefficients, travel times, irrigation efficiencies), calibration parameters (e.g., canal seepage %, conductivity), methods (e.g., reservoir mass-balance equations, crop ET, effective precipitation) and water quality (salinity in Middle Rio Grande Valley).

The physical processes represented in URGWOM include mass balance constrained reservoir,

reach, groundwater, and agricultural use dynamics, more specifically:

• Reservoir mass balance dynamics modeled include inflows, evaporation losses, seepage, precipitation gains, controlled reservoir releases, and spills.
• Reach mass balance dynamics modeled include tributary and wastewater inflows, agricultural diversions and return flows, municipal diversions, routing, open water evaporation, and surface water groundwater interactions.
• Shallow groundwater mass balance dynamics modeled include river seepage or

gain, canal seepage, drain capture, crop irrigation deep percolation, riparian evapotranspiration, and groundwater movement within the shallow aquifer and to and from the surrounding regional aquifer.

• Agricultural mass balance dynamics include diversions, evapotranspiration, soil moisture, supplemental groundwater pumping, and return flows to surface water system and shallow groundwater aquifer.
• The interaction between the shallow alluvial aquifer and the deep (pumping layer) aquifer has been simulated in the model since 2022.  Prior to this time this flux was based on data from the regional groundwater models (MODFLOW).

The Physical Model Appendix (PHYGRAPH) file contains plots of data used to develop travel times and loss rates which are tabulated in Volume 1. Physical Model Appendix (PHYGRAPH)

2a. Policy Rules Documentation

Volume 2a describes river operations in the Rio Grande system in Colorado, the Middle Rio Grande, and the Lower Rio Grande as implemented by the URGWOM Operations ruleset. The URGWOM Operations ruleset is organized based on these basin delineations, with an additional group of rules associated with data input and Compact accounting that are relevant to operations throughout the basin. Following the URGWOM Operations ruleset, this documentation is organized into four main sections corresponding to Forecast Error (for Planning Studies) and Compact rules, Colorado rules, MRG rules, and LRG rules. This document serves as a reference for URGWOM users working with the RiverWare Policy Language (RPL) developed Operations Ruleset and provides a means to review the policy as coded in the model.

Volume 2a is based on URGWOM version 7.4, at which time there were 275 rules in 39 policy groups.  Assignments for the different parameters completed with each rule are based on the priority for the rule. For example, setting an outflow based on flood control policy will have a higher priority than a delivery to water users. The rules are listed based on priority and are executed, or fired, in reverse order, with rule number 275 firing first in each timestep and rule number 1 firing last. The rules are ordered to set outflows from the dams from upstream to downstream. These rules represent basin policy for such objectives as setting diversions, recording water transfers, meeting downstream target flows, and adhering to flood control operations criteria, all of which ultimately determine the outflow from each modeled dam in the basin.  The current version of URGWOM ruleset, Version 9.2, has 317 rules, 42 policy groups and 55 utility groups.

2b.  Initialization Rules Documentation

Volume 2b. describes the Initialization Ruleset in URGWOM that sets input values to be used in the model prior to a simulation run.  The difference between Initialization rules and Policy (Operational) rules is that the former are executed only a single time before the beginning of the run. Thus, Initialization rules can be used to set values such as initial Storage or Pool Elevation on a reservoir, and other parameters required before the start of an Accounting and/or Rulebased Simulation model run. Initialization rules are always contained within a model file, whereas Policy (Operational) rules can be in a separate ruleset file or contained within a model file.

The Initialization rules are sorted in 25 different policy groups (URGWOM Version 9.3). Policy Groups are groups of rules and/or functions that typically have some relationship to one another, e.g., they all set similar parameters or pertain to one object such as a reservoir. Assignments for the different parameters as completed with each rule are based on the priority for the rule. For example, checking that input values (by direct input or rule) will have a higher priority than rules that have previously set a value. The rules are listed based on priority and are executed, or fired, in reverse order. For URGWOM version 9.2, there are 122 Initialization rules coded which represent the policy for setting input values based on the needs of the run-type executed (e.g., Accounting, AOP, etc.).

2c.  Expression Slot Functions Documentation

Volume 2c. serves as a reference for users working on Expression Slot Functions in URGWOM. Expression slots are user-defined slots in a model object whose value is computed from a user-defined arithmetic expression. Expressions are developed using the RiverWare Policy Language (RPL) similar to Operational Policy and Initialization rules. Within URGWOM, expression slots exist in 84 different data objects and are used to summarize or aggregate output data during, or at the completion of, a model run. The data objects are associated with a range of model aspects including reach flows, reservoir operations, diversion calculations and contractor accounting. The majority of these objects are associated with USBR San Juan - Chama Project accounting. Additional data objects specific to Annual Operating Plan (AOP) and Rio Grande Compact Commission reports are located in this workspace area and organized in a similar manner.

3.  Accounting Methods and Concepts

This document serves as a reference for users working with the water accounting features in URGWOM.  The accounting module of URGWOM is used by the USBR’s Albuquerque Area Office for updating the status of accounts for contractors for San Juan-Chama Project water and other water users in the Rio Grande Basin in New Mexico. This module also serves to ensure that the storage and movement of San Juan-Chama water is not included in the calculations of downstream delivery obligations prescribed by the Rio Grande Compact.

The accounting module primarily solves for reservoir inflow using observed flows and reservoir stages, and then calculates all additional loss and storage data to report and store in the model and database. This is the same operation originally developed by the USBR. The accounting module in RiverWare, however, improves the accounting process by linking the releases of San Juan- Chama water to the inflows of the next downstream reservoir. In the process, URGWOM creates (positive or negative) local inflows between reservoirs, representing the unaccounted-for differences between what leaves the upstream reservoir and what arrives downstream. The accounting module calculates total water storage, Rio Grande storage, San Juan-Chama Project water storage, and in some reservoirs, sediment deposition and sediment content effects.

4.  Database Documentation

URGWOM data are stored in a US Army Corps of Engineers HEC-DSS (https://www.hec.usace.army.mil/software/hec-dss/) file. The October, 2023 URGWOM DSS groundwater database includes 699 records of groundwater level data and The June 2024 URGWOM DSS database includes 1,195 records of data for use in URGWOM; each record can contain thousands of individual data points. Each record is organized by Parts A-F. Each Part represents an aspect of the data within that record. In general, the following describes the aspect that each DSS Part represents:

A Part: Group

B Part: Location

C Part: Parameter (temperature, precipitation, diversion, storage, inflow, evaporation rate, etc.)

D Part: Period of Record

E Part: Time Interval (i.e., day, year, etc.)

F Part: Description/Metadata

Metadata is information about data including its source or how it was calculated. Metadata storage in DSS is difficult, and a metadata workbook catalog is developed in Excel to allow metadata associated with DSS records to be stored and searched. To address the need for metadata that can be quickly accessed for any data record, in a format that is reasonably easy to maintain, and in which 1:1 mapping to the DSS database can be checked, a single metadata workbook has been developed.

The metadata workbook includes three lists, one list of all B Part / C Part combinations, and associated record specific metadata. A second list contains a list of all B Parts in the database and B Part specific metadata if any, and a third list contains a list of all C Parts in the database and C Part specific metadata if any.

The current metadata workbook catalog can be found here URGWOM Database Catalog July 2021.xlsx

5.  DMI and SCT Documentation

Volume 5 serves as a reference for users working on Data Management Interfaces (DMIs) and System Control Tables (SCTs) in URGWOM.  The RiverWare DMI provides a mechanism to transfer data into and out of RiverWare in a highly configurable and automated manner. While data can be moved in and out of URGWOM manually, or with copy and paste commands, or with copy and paste to and from SCTs (see below), for large scale data transfer, DMIs are the URGWOM workhorse.

The RiverWare SCT is a customizable, editable view of slots and data in a RiverWare model. SCTs are a tool that can be created quickly by a model user for a variety of purposes. As such, this document is not intended to be a comprehensive list of URGWOM SCTs, but rather a list of URGWOM SCTs commonly used by lead agencies.

6. Script Documentation (User's Manual)

Volume 6 serves as a reference for the scripts used to set up different URGWOM model runs (and thus also as an URGWOM User’s Manual).  Scripts allow users to organize and run sequences of actions. This allows users to automate many of the tasks involved in operating a model.  A script might be used to change the run range, set a value that represents the type of run, change the controller, set a date trigger referenced by a rule, set values on slots, change a method type, clear a slot’s flag, or even run another script.  Since the development of Script functionality in RiverWare, the steps necessary to set up URGWOM for Accounting Runs, AOP Runs, daily or monthly timestep Planning Runs, daily or monthly timestep Unregulated Flow Runs, or Real Time Runs have been captured by scripts.  This formalization of steps has largely supplanted the need for an URGWOM User’s Manual which previously had listed the steps necessary to set up different URGWOM model runs.