Improving Water Quality in Minnesota: Simplifying HSPF Modeling and Assessing Watershed Conditions with SAM

Minnesota Pollution Control Agency

The Minnesota Pollution Control Agency sought qualified consultants for HSPF modeling and watershed services. They needed assistance assessing watershed conditions, developing restoration and protection strategies, and preparing Total Maximum Daily Loads (TMDL) for impaired lakes and rivers. They were looking for a solution to make the complex HSPF models more accessible to non-modeling end users.

RESPEC was one of only two qualified consultants selected for the job. To make the complex HSPF models more user-friendly, we developed SAM, a decision support system that serves as a graphical interface to the HSPF model applications. SAM simplifies the technical input and results of HSPF, making it more accessible to resource professionals who can efficiently plan and implement actions to restore or protect water quality in specific geographic areas.

RESPEC has an impressive track record, having developed watershed models for approximately 75 percent of Minnesota’s 8-Digit Hydrologic Unit Codes. These models simulate hydrology and water quality parameters over an extended time series, including flow, temperature, sediment, nutrients, dissolved oxygen, chlorophyll a, and oxygen demand. The models assess sediment and nutrient sources, generate TMDL tables, and evaluate implementation strategies. RESPEC’s involvement also included the following:

  • Assessing initial watershed conditions
  • Developing restoration and protection strategies
  • Working with stakeholders to address their local priorities and gain support for implementing the strategy

Thanks to SAM as a decision support tool, Minnesota’s investment in HSPF has reached a wider audience. SAM provides a comprehensive approach to achieving water quality goals set by TMDLs and watershed planning efforts. It helps users understand watershed conditions, identify priority areas, and select best management practices to provide the greatest water quality benefits for each dollar invested. By simplifying complex hydrologic and water quality model applications, SAM provides transparent estimates of significant pollutant sources in watersheds, ultimately restoring and protecting water quality.