Specifications include, but are not limited to: The project consists of retrofitting two detention ponds located on the LDS Church property off Essex Way. One of the ponds is located in the front of the property (North pond) and the other pond is located in the back of the property (South pond). The North pond was identified as a good site for a retrofit because of the availability of open space, visibility, and ease of access. A retrofit was developed for the ponds under the Flow Restoration Plan (FRP) for Indian Brook. The retrofit would convert both ponds to underground stone storage and infiltration systems. Existing piping would be modified to bring the road and parking lot storm drainage into and out of the storage areas. Pretreatment of the inflow would be provided by a hydraulic swirl separator or similar structure. This underground system would create a usable space for passive use and will require less maintenance. An important component of this project is the optimization of phosphorus removal by the systems. Currently, the proposed systems mitigate 3.34 lbs. of phosphorus. With the Lake Champlain Phosphorus TMDL, the Town is required to reduce the amount of phosphorus entering the Lake by 20%. The Town would like to ensure that options are explored that will enhance the proposed system and maximize phosphorus removal. Use of mixed filter media, such as but not limited to sand, wood chips, waste sludge from Champlain Water District (CWD) and potential underdrains would significantly increase the removal of phosphorus. It should be noted that this project lies entirely within lands owned by the LDS Church and Town-owned land and Right-Of-Way. A concept plan was developed for this project to enable land easement discussions with the LDS Church. The Church has tentatively agreed to use the land area for this purpose. A copy of the concept plan is provided with this RFQ.
