During 2015 and 2016, Barr assisted the MPCA with content updates to the infiltration sections of the Minnesota Stormwater Manual. This wiki-style document is used by stormwater practitioners to select and implement the most effective and cost-efficient BMPs for managing stormwater runoff volume and pollutants and to meet stormwater permitting regulatory requirements. Updates included the overview, types of infiltration, design criteria, cold-climate suitability, construction specifications, and operation and maintenance of infiltration practices.
In addition, we created new guidance for understanding and interpreting soils and soil-boring reports as well as new case-study summaries of infiltration project examples. The types of infiltration practices discussed included the infiltration basin, infiltration trench (including tree trench/tree box), bioinfiltration, permeable pavement, swale with check dam, drywell, and underground infiltration measures. The deliverables included illustrations that allow users to distinguish the various properties of each BMP, as well as schematics to show updates to technical terms for design criteria.
Other deliverables included selection matrices to help choose infiltration media, examples of access and maintenance agreements and easements, and inspection forms and checklists for design, construction, and post-construction operation and maintenance.
The manual can be found on the MPCA’s website at https://stormwater.pca.state.mn.us/index.php?title=Main_Page.
Barr also worked with the MPCA to develop an infiltration-practices webinar (https://youtu.be/WRAVEmR4ExI) based on content developed for the manual.