What is HAWQS?

The Hydrologic and Water Quality System (HAWQS) is a web-based interactive water quantity and quality modeling system that employs as its core modeling engine the Soil and Water Assessment Tool (SWAT), an internationally-recognized public domain model. HAWQS provides users with interactive web interfaces and maps; pre-loaded input data; outputs that include tables, charts, and raw output data; a user guide, and online development, execution, and storage of a user's modeling projects.

HAWQS substantially enhances the usability of SWAT to simulate the effects of management practices based on an extensive array of crops, soils, natural vegetation types, land uses, and other scenarios for hydrology and the following water quality parameters:

  • Sediment
  • Pathogens
  • Nutrients
  • Biological oxygen demand
  • Dissolved oxygen
  • Pesticides
  • Water temperature

HAWQS users can select from three watershed scales or hydrologic unit codes (HUCS) – 8-digit ~700mi2; 10-digit ~227 mi2; and 12-digit ~40mi2 – to run simulations. HAWQS allows for further aggregation and scalability of daily, monthly, and annual estimates of water quality across large geographic areas up to and including the continental United States.

The United States Environmental Protection Agency (USEPA) Office of Water supports and provides project management and funding for HAWQS. The Texas A&M University Spatial Sciences Laboratory and EPA subject matter experts provide ongoing technical support including system design, modeling, and software development. The United States Department of Agriculture (USDA) and Texas A&M University jointly developed SWAT and have actively supported the model for more than 25 years.

View the HAWQS brochure.

How does HAWQS work?

  1. Log in or register for a new account to get started

  2. Create a project

    • Choose a desired catchment resolution: HUC8, HUC10 or HUC12
    • Select your ending HUC ID from a map
  3. Create a scenario

    • Specify the model run duration and model run frequency
  4. Make further customizations to your model

    • Set HRUs to eliminate minor land uses, soils and slopes
    • Edit general watershed inputs and databases (basin, fertilizer, urban, nutrient efficiency, land use update)
    • Edit subbasin inputs (curve number, potholes, sediment routing, climate change/sensitivity, point source)
    • Modify SWAT output by selecting reach, subbasin and HRU parameters
  5. Generate SWAT input files

  6. Generate SWAT Access database for SWATeditor

  7. Run the available versions of SWAT

  8. Analyze your results

    • Run SWAT Check—a program designed to identify potential model problems
    • Generate output reach statistics
    • View output summary charts
    • Download a zip of all project files