The USGS is at the forefront of devising new techniques and computer software to solve practical problems in the study of water resources.
Predictive models are needed to make informed decisions in many emerging areas related to the effects of water resources development. New models and methods enhance all USGS water programs. State and local governments as well as scientists and engineers in the private sector regularly use USGS models as an integral part of their work.
Numerical simulation software is critical to the water resource studies of the USGS Water Availability and Use Science Program (WAUSP). Software developed and maintained by the USGS such as the Precipitation Runoff Modeling System (PRMS), Water Balance Model (WBM), the International River Interface Cooperative (iRIC) software, Soil-Water Balance (SWB), MODFLOW, GSFLOW, PEST++, and Groundwater Toolbox are integral to WAUSP studies and are required to effectively forecast future conditions. Moreover, this software is used in studies across the USGS.
WAUSP supports modeling software development to:
- simulate groundwater and surface-water flow with computer codes such as PRMS, MODFLOW, GSFLOW, and iRIC;
- allow the creation and viewing of groundwater and surface-water models with graphical user interfaces such as ModelMuse and web applications such as GWWebFlow;
- automate the fine-tuning (calibration) of models to real-world data with PEST++, pyEMU, and Luca;
- separate the primary components of streamflow into runoff from the land surface and groundwater discharge from adjoining aquifers with the Groundwater Toolbox;
- store and retrieve subsurface information with the GeoLog Locator web service;
- estimate groundwater recharge with the Soil-Water Balance (SWB) model;
- analyze temperature, flowmeter, and geophysical data.
In 2019, support for model development totaled approximately $2.3M, of which $1.2M was designated as groundwater model development, maintenance, and sustainability research and development to advance water science.
In late 2019, the USGS released version 6.1.0 of its flagship hydrologic simulation code MODFLOW. Named “MODFLOW 6,” the code has been redesigned to provide greater flexibility to simulate regional- and local-scale groundwater systems simultaneously and for improved integration with other types of watershed, chemical-transport, and water-operations models. This version of MODFLOW 6 includes the simulation of land subsidence and compaction.
In 2019, the USGS released version 1.0.5 of the Surface-Water Toolbox, which is a graphical and mapping interface for analysis of hydrologic data developed in collaboration with the US Environmental Protection Agency. The software directly accesses streamflow data from the USGS National Water Information System and provides many tools for statistical analysis of the data.
During 2019, the USGS released version 5.0.0 of the Precipitation Runoff Modeling System (PRMS). A number of updates to the PRMS model code have been made including modules for dynamic parameters, water use, improved stream and lake flow routing, and updates to surface-depression storage simulation
During 2020, work will continue to make USGS data more accessible to water-resource managers, scientists, and the public through web applications to support viewing of groundwater-modeling results (GWWebFlow) and retrieval of borehole geophysical logs (USGS GeoLog Locator).
MODFLOW and Related Programs
National Hydrologic Model Infrastructure
Documentation for the MODFLOW 6 Groundwater Flow Model
Documentation for the MODFLOW 6 framework
MODFLOW and Related ProgramsMODFLOW is the USGS's modular hydrologic model. MODFLOW is considered an international standard for simulating and predicting groundwater conditions and groundwater/surface-water interactions. MODFLOW 6 is presently the core MODFLOW version distributed by the USGS. The previous core version, MODFLOW-2005, is actively maintained and supported as well.
National Hydrologic Model InfrastructureThe USGS National Hydrologic Model (NHM) infrastructure supports the efficient construction of local-, regional-, and national-scale hydrologic models. The NHM infrastructure consists of: 1) an underlying geospatial fabric of modeling units with an associated parameter database, 2) a model input data archive, and 3) a repository of the physical model simulation code bases.
GWWebFlowGWWebFlow is a browser-based groundwater model viewer designed to allow users to easily explore model inputs and outputs for published and approved USGS models. It currently supports the MODFLOW family of models, including MODFLOW2005, MODFLOW-NWT, MT3DMS and SEAWAT.
Documentation for the MODFLOW 6 Groundwater Flow ModelThis report documents the Groundwater Flow (GWF) Model for a new version of MODFLOW called MODFLOW 6. The GWF Model for MODFLOW 6 is based on a generalized control-volume ﬁnite-difference approach in which a cell can be hydraulically connected to any number of surrounding cells. Users can deﬁne the model grid using one of three discretization packages, including (1) a structured discretization pac
Documentation for the MODFLOW 6 frameworkMODFLOW is a popular open-source groundwater flow model distributed by the U.S. Geological Survey. Growing interest in surface and groundwater interactions, local refinement with nested and unstructured grids, karst groundwater flow, solute transport, and saltwater intrusion, has led to the development of numerous MODFLOW versions. Often times, there are incompatibilities between these different M