South Washington Watershed District Plan Update
South Washington Watershed District Plan Update

Location:  Washington County, MN
Client:  South Washington Watershed District

Background

The South Washington Watershed District (SWWD) is comprised of portions of the Cities of Woodbury, Cottage Grove, Newport, and Afton, within the southern portion of Washington County and the seven- county Minneapolis-St. Paul metropolitan area. The SWWD is a local unit of government with Ad Valorem tax authority, responsible for addressing regional water management issues in accordance with Minnesota Statutes 103B and 103D. The Minneapolis – St. Paul metropolitan area is expanding rapidly, generally in a southeasterly direction across the SWWD. The portions of the District within the Cities of Woodbury and Cottage Grove are highly urbanized, while the southeastern portion remains relatively rural. The Mississippi River borders the District on the east and south. 

The SWWD faces several unique and potentially substantive water management issues. The portion of the District comprised by the City of Woodbury lacks a surface water outlet (i.e., it is landlocked). An outlet is necessary for safely conveying surface water runoff from the urbanizing landscape. Soils across the District exhibit high infiltration rates, making groundwater management and protection a substantive concern. New National Point Discharge Elimination System storm water permitting requirements for municipalities and construction sites place additional requirements on the cities comprising the District. 

Under Minnesota Rule Chapter 103(d) the SWWD is required to update their watershed district plan at least once in every 10-year period. The plan must address not only surface and ground water issues, but can include natural resource, wetland or other important concerns of the District. The SWWD retained HEI to complete their 10-year plan update. 

The Project

The traditional approach to completing a plan update includes the development of considerable background information and an organizational format which sometimes makes using the plan difficult. The SWWD wanted a unique and different approach which results in a readily usable plan. The District’s approach consisted of developing a plan very much focused on the implementation of specific regional projects, policies and programs and water management performance specifications and design criteria. The modular plan format substantially increased the ease of use for the SWWD and those cities and townships affected by the plan. The plan’s focus became the annual and 10-year work plans used to define the short-term and long-term activities and financial needs of the District.

Another unique aspect of the plan update was the development of performance specifications and design criteria which can be used by the cities and townships within the District as a tool for complying with their municipal storm water NPDES permitting requirements. The plan establishes maximum allowable inter-community discharge rates, to reduce the likelihood of flooding within the District. Other activities completed as a part of the plan update included:

  • Describing the physical and natural resource characteristics of the District;
  • Completing GIS maps to assist with describing the District’s resources;
  • Obtaining and reviewing all previous reports and publications and creating an electronic bibliography. Identifying the relevant information within these reports and publications needed for the plan update;
  • Gathering and analyzing existing precipitation, stream gaging, lake level, and water quality data to establish water quality improvement goals, performance specifications and design standards;
  • Developing water management goals and establishing policies and action items to accomplish them;
  • Revising existing hydrologic and hydraulic models and using the models to establish performance specifications and design criteria; and
  • Developing a capital improvement program for the District. 
Stakeholder involvement activities were also completed by Houston Engineering as a part of the plan update process. These activities included preparing a Stakeholder Involvement Plan, executing that plan, preparing and presenting information to the public and conducting workshops with the Board of Managers. 

Client Benefits

  • Plan’s implementation focus greatly improved ease of use and made the plan a living, vital part of District operation. 
  • Framework provided by the plan assisted cities with NPDES compliance, saving valuable local resources and providing a consistent approach across the District. 
  • Outcome based focus of the plan included a report card type review of District activities and an objective measure of annual progress.