Texas A&M College of Agriculture and Life Sciences
TAMU Hydrologic Modeling Inventory
A comprehensive inventory of models used in Hydrology, Hydraulic, Water Quality and Water Use Management Assessments

SPARROW

SPARROW (SPAtially Referenced Regressions On Watershed attributes) is a watershed modeling technique for relating water-quality measurements made at a network of monitoring stations to attributes of the watersheds such as contaminant sources and environmental factors that affect rates of delivery to streams and in-stream processing. The core of the model consists of a nonlinear regression equation describing the non-conservative transport of contaminants from point and non-point (or “diffuse”) sources on land to rivers and through the stream and river network.

The model estimates contaminant concentrations, fluxes (or “mass,” which is the product of concentration and streamflow), and yields in streams (mass of nutrients entering a stream per acre of land), and evaluates the contributions of selected contaminant sources and watershed properties that control transport throughout large river networks. It empirically estimates the origin and fate of contaminants in streams and receiving bodies, and quantifies uncertainties in these estimates based on coefficient error and unexplained variability in the observed data.

Website:      https://water.usgs.gov/sparrow

Watershed Management Optimization Support Tool (WMOST)

The Watershed Management Optimization Support Tool (WMOST) is a decision support tool that facilitates integrated water management at the local or small watershed scale. WMOST models the environmental effects and costs of management decisions in a watershed context that is, accounting for the direct and indirect effects of decisions. WMOST is intended to be a screening tool used as part of an integrated watershed management process.

Website:        https://www.epa.gov/ceam/wmost

 

QUAL2K

QUAL2K is a Microsoft Windows based application for river and stream water quality modeling. QUAL2K is an updated version of QUAL2E with improvements in model segmentation, forms of carbonaceous BOD evaluated, particulate organic matter simulation, anoxia and denitrification modeling, sediment-water dissolved oxygen and nutrient fluxes, explicit simulation of attached bottom algae, light extinction calculation, enhanced pH simulation, and pathogen removal functions. The ecologically-focused model simulates daily water quality, as either steady-state or dynamic system.  Includes estimation of biological oxygen demand, nitrogen, phosphorus, coliforms and pH.

 

Website:  http://www.qual2k.com

EPANET

EPANET was developed as a tool for understanding the movement and fate of drinking water constituents within distribution systems, and can be used for many different kinds of applications in distribution systems analysis. EPANET can be used to design and size new water infrastructure, retrofit existing aging infrastructure, optimize operations of tanks and pumps, reduce energy usage, investigate water quality problems, and prepare for emergencies. It can also be used to model contamination threats and evaluate resilience to security threats or natural disasters. EPANET’s user interface provides a visual network editor that simplifies the process of building piping network models and editing their properties and data.

 

Website:  https://www.epa.gov/water-research/epanet

Precipitation Runoff Modeling System (PRMS)

The Precipitation-Runoff Modeling System is a deterministic, distributed-parameter, physical process based modeling system used to evaluate the response of various combinations of climate and land use on streamflow and general watershed hydrology.  Response to normal and extreme rainfall and snowmelt can be simulated to evaluate changes in water-balance relations, streamflow regimes, soil-moisture relations, and groundwater recharge. Each hydrologic process is represented within PRMS by an algorithm that is based on a physical law or an empirical relation with measured or estimated characteristics.
Distributed-parameter capabilities are provided by partitioning a watershed into hydrologic response units (HRUs) that are based on the physical attributes of the watershed such as land-surface elevation, slope and aspect, vegetation type, soil type, and spatio-temporal climate patterns. The physical attributes and hydrologic response of each HRU are assumed to be homogeneous. A water balance and an energy balance are computed daily for each HRU. The sum of the responses of all HRUs, weighted on a unit-area basis, produces the daily watershed response in the most basic configuration. In addition, PRMS can provide more sophisticated methods of internal routing that are available for more complex modeling applications.

 

Website:  https://wwwbrr.cr.usgs.gov/projects/SW_MoWS/PRMS.html

Coupled Groundwater and Surface Water Flow model (GSFLOW)

GSFLOW was developed to simulate coupled groundwater/surface-water flow in one or more watersheds by simultaneously simulating flow across the land surface, within subsurface saturated and unsaturated materials, and within streams and lakes. Climate data consisting of measured or estimated precipitation, air temperature, and solar radiation, as well as groundwater stresses (such as withdrawals) and boundary conditions are the driving factors for a GSFLOW simulation. GSFLOW can be used to evaluate the effects of such factors as land-use change, climate variability, and groundwater withdrawals on surface and subsurface flow for watersheds that range from a few square kilometers to several thousand square kilometers, and for time periods that range from months to several decades.

Website: https://water.usgs.gov/ogw/gsflow/

MIKE BASIN

MIKE BASIN is a general multi-purpose river network model for river basin management and planning. The model uses ArcView GIS as Graphical User Interface, and fully utilizing a number of GIS procedures, including catchment delineation etc. The purpose of MIKE BASIN is the simulation of natural inflows, multiple multipurpose reservoir operation and water right allocation in river basins based on a prioritized water accounting procedure. It allows for conjunctive use of surface water and ground water. An extension to the basic module includes water quality simulation based on point and non-point sources.

Description:  MIKE BASIN.pdf                  Website:   https://www.mikepoweredbydhi.com/products/mike-hydro-basin

Water Resource Integrated Modeling System

Water Resource Integrated Modeling System (WRIMS model engine or WRIMS) (formally named CALSIM) is a generalized water resources modeling system for evaluating operational alternatives of large, complex river basins. WRIMS integrates a simulation language for flexible operational criteria specification, a linear programming solver for efficient water allocation decisions, and graphics capabilities for ease of use. These combined capabilities provide a comprehensive and powerful modeling tool for water resource systems simulation. WRIMS 2 includes an open source Cbc solver and a commercial solver named XA which needs the users to purchase a license.

Description:  WRIMS.pdf              Website:   https://water.ca.gov/Library/Modeling-and-Analysis/Modeling-Platforms/Water-Resource-Integrated-Modeling-System

History of Water law and management in Texas

Water has been a cherished, regulated resource in Texas from the 1600’s when Texas was under the Spanish rule.

Water law in Texas began early in Texas history, when the San Antonio area was first settled by the Spanish. Spanish law determined that the rights to surface water from creeks, rivers, and lakes were riparian: that is, the landowners adjacent to a body of water had the right to determine how that water was used. This doctrine remained essentially unchanged even after Texas independence and statehood. However, the Texas Supreme Court noted as early as 1872 that riparian doctrine was unsuitable as settlement moved into the arid regions of West Texas and the Panhandle.

Beginning in the 1890s, Texas began to implement a legal doctrine known as prior appropriation. Simply put, prior appropriation means that the state issues water rights for surface water with multiple stakeholders. Rights may be assigned according to seniority among the permit holders, or allocated according to a complex formula between residential, industrial, and agricultural users. In 1913, the legislature created the Texas Water Commission (now the Texas Commission on Environmental Quality) to oversee water appropriations. Prior appropriation was implemented incrementally over many decades, and conflicts between permit holders and those with existing riparian rights were a source of numerous court cases well into the 1980s.

The legal complexities add to the challenge of managing this resource necessary for life and commerce, especially in times of extreme scarcity, when the water rights allocated to a particular stream exceed the amount of water available