Feasibility Evaluation of Phosphorus Removal via Engineered Ecosystems in the St Albans Bay Watershed

Bolin, G.; Braun, D. (2018). Feasibility Evaluation of Phosphorus Removal via Engineered Ecosystems in the St Albans Bay Watershed, 2018 (Technical Report No. 86). Grand Isle, VT. Lake Champlain Basin Program

Development of a treatment train facility to remove phosphorus from Jewett Brook prior to discharge to St. Albans Bay has the potential to accelerate water quality improvements in St. Albans Bay. Jewett Brook has
chronically elevated concentrations of phosphorus. Implementing a treatment train facility on Jewett Brook would involve withdrawing, treating, and releasing a portion of the streamflow. This facility could extend and
enhance ongoing agency programs focused on implementation of agricultural conservation practices and nutrient management and bring the St. Albans Bay phosphorus targets within reach.

Representatives of the local, state, and federal government bodies that will determine the outcome of this project were convened to evaluate the regulatory feasibility of developing a treatment facility on Jewett Brook.
The evaluation served to clarify which resource concerns were paramount as well as possible ways to avoid or mitigate impacts to these resources. The resource concerns that emerged as most challenging are 1)
entrainment of fish (specifically larvae) in intake pumps; 2) potential impacts to aquatic organisms and their habitats due to warming of water at the discharge location; and 3) potential impacts to fish species recruitment
due to alteration of the natural hydraulic flow within Jewett Brook and the Black Creek Wildlife Management Area.

Stone has given some consideration to methods by which resource concerns could be avoided or mitigated and will examine these concerns further in the technical feasibility evaluation phase of the project. Most of the resource concerns discussed could be addressed through appropriate siting and design of the treatment facility. Although creation of constructed wetlands is proposed, development of this project will involve considerable
efforts to avoid and minimize impacts to natural wetlands. Facility siting and design will determine which specific permits will need to be filed and the conditions that will need to be met to construct the facility. Other
resource concerns could be addressed in the operation of the facility, including adjusting the timing and rate of water withdrawal and discharge to minimize heating and entrainment of larval fish.

Stone is confident based on our committee discussions, regulation review, and preliminary analyses that a treatment train facility project can and should advance to the technical evaluation, conceptual design, and
costing stage.