2011-2012 Stormwater Infrastructure Mapping Update Project
Work continues on the infrastructure mapping update project . As of May 2012, locations of all known manholes, catch basins, water valves and hydrants have been collected. See here for an example of what the draft data looks like. Additionally, elevation measurements of manholes in the Englesby Watershed have been collected for future modeling purposes. During the Summer 2012, City staff will be working with our consultants at Weston & Sampson to resolve discrepancies. Discrepancy resolution is a common step in these types of updates as there are places where it is not clear how infrastructure flows or is connected. We will also be setting up and populating the larger database where infrastructure inventory (pipe material, pipe diameter etc) information will be kept and ultimately where service records will be attached for improved operational efficiency.
Additionally, several divisions within the Department of Public Works, along with the Department of Parks & Recreation are partnering to acquire a highly accurate GPS unit so that we can continue to collect additional points that were not located during this update and can collect new points as they are added (new manholes, hydrants etc).
This project is made possible, in part, due to a grant from the Vermont Agency of Transportation which reimburses the City for 80% of its costs, up to $80K.
2011 - 2012 Blanchard Beach Wetland Restoration and Water Quality Improvement Project
This project goals are to evaluate the sources of pollutants in the watershed for the small "Oakledge" tributary that drains to the south section of Blanchard Beach (map), to restore the small wetland that is at the mouth of the tributary's outfall, and to make overall water quality improvements which improve water quality in the wetland area and at Blanchard Beach.
A feasibility and stormwater runoff and pollutant source analysis has been completed. Please see the "Oakledge Tributary Subwatershed Map."
Based on the feasibility study, City staff and our consultants, Lakeside Environmental Group, have selected a number of water quality improvements and developed a restoration plan for a section of the wetland. The water quality improvements involve the stabilization of the eroding swale along the east side of the Oakledge entrance, the installation of a swirl separator, which will remove sediment and other sediment bound pollutants (oils, bacteria, nutrients) from the runoff coming from the paved surfaces in Oakledge and for much of the lower section of Flynn Avenue. Portions of the wetland will be restored by removing some of the accumulated material that has been deposited over the years and creating small micro-pools with wetland plantings (see Draft Lower Blanchard Project). Like natural wetlands, we hope that this restored wetland will have increased water quality mitigation functions compared to the degraded system that currently exists, further improving the water quality at Blanchard Beach.
Implementation of the project is scheduled for late August/early September 2012.
This project is funded, in part, by grants from the Lake Champlain Basin Program ($25K) and VT Dept. of Environmental Conservation Ecosystem Restoration Program ($45K)
2012 Cherry Street Silva Cell: Urban Tree Canopy Sustainability and Stormwater Reduction Project
Maintaining and increasing the urban tree canopy is an important part of reducing stormwater runoff in the City of Burlington as trees intercept rainfall within their canopy and allow the water to evaporate back into the atmosphere rather than reaching our drainage systems. Additionally, tree planting beds that are designed to provide the tree with sufficient un-compacted soil volume (and thereby encourage large, healthy canopies) can also be used to soak up stormwater. The water is available for irrigation of the tree which, in return, will pull the water into its roots and evapotranspirate it back to the atmosphere. Excess amounts of water are filtered through the soil media and returned slowly back to the drainage system. It is the perfect partnership!
The challenge hinges on providing the tree with the necessary uncompacted soil volume in a highly urbanized environment where the soil is compacted due to the need for pavement systems that can support traffic,. However, some technologies have emerged which can provide the structural support necessary for the urban environment while maintaining uncompacted soils for the tree and for stormwater storage and filtration.
The Burlington Stormwater Program and the Department of Parks are working together to install a tree based stormwater system on Upper Cherry Street using Silva Cell technology. This modular frame/deck system supports the pavement systems and allows utilities to pass through the soil and frame structure.
Design is underway and implementation is scheduled for August 2012. The project is funded, in part, by a 319 Grant through the VT Dept. of Environmental Conservation ($25K).