Denise Nelson from Greeley and Hansen LLC in Richmond, VA, describes how Greeley and Hansen used Envision to evaluate a bioretention project in order to determine the applicability of the tool to stormwater infrastructure. Here is her description of the project and how they applied the rating system to assess their project.
The project involved the installation of two bioretention basins and six infiltration planters at two elementary schools in central Virginia. The project was funded by the State clean water revolving loan fund to construct a Green Infrastructure pilot project in the combined sewer area. The objective of the pilot project was to identify the benefits and cost effectiveness of applying green infrastructure to reduce stormwater runoff and improve water quality in the receiving water body. The project will provide valuable information for the evaluatin the eed to extend green practices to other areas for stormwater management and combined sewer overflow control. The Department of Public Utilities and Public School Board as well as other related departments collaborated to support the project. Signs, handouts, and a ribbon cutting ceremony were used to educate and advertise the positive impacts to the students and community.
Asphalt pavement and concrete sidewalks were removed to install the bioretention basins and infiltration planters (see photos below). The facilities work by collecting water in the natural low points on each site within a landscaped area, filtering the contaminants, and storing a significant volume of the runoff for slow infiltration. Bioretention was designed to provide up to 80% annual runoff reduction, 50% Phosphorus removal, and 60% Nitrogen removal from the contributing drainage area.
The project team used Envision to evaluate the design while construction was underway. Envision was not used as a design tool.
The results of the Envision assessment are listed below.
The project rated highest in Natural World (68%) and Quality of Life (67%) due to the extensive community involvement, educational outreach initiatives, and nature of the work as an LID project. Innovation points were awarded for:
- Improving quality of life
- Stimulating sustainable growth and development
- Preserving views and local character
- Enhancing a public space
- Restoring disturbed soils.
The project also scored well in Leadership (62%) and Resource Allocation (44%). High points were awarded in these categories for protecting water availability and reducing water consumption, using regional materials, and providing leadership, collaboration and infrastructure integration.
The project scored lowest in Climate and Risk (33%). Many of these credits were not applicable due to the nature of the project like energy conservation.
Overall, the project earned 55% of total points possible. This is a significant achievement and would likely qualify for a silver award. However, it is key to note these points:
- Envision was not used as a tool during the design, but was applied after the design was complete. Using the tool during design would have identified other aspects of sustainability that could have been incorporated into the project.
- The assessment was performed by the project team and has not been third-party Verified. Discussions with the Verifier could result in the identification of higher (or lower) point values for the credits.
Envision Assessment took approximately 4 hours to complete (excluding the time to compile the required documentation for Verification). The project registration and verification would cost $3,400 based on the project construction cost of $535,000. The team will consider registering this project with ISI when applications are accepted in the fall.