Appendices A -E
The goal of this project was to demonstrate how, through whole farm nutrient management,
improvements can be made to water quality through reduced phosphorus (P) loading and
improved farm viability. Through this project we worked closely with five farms located in critical
source areas to build a program that implements comprehensive P management strategies on a
whole farm level. This diverse group of farmers included a Large Farm Operation (St. Albans
Bay Watershed), Medium Farm Operation (Lake Carmi), Certified Small Farm Operation (Rock
River Watershed), organic grass-fed farm (Rock River Watershed), and one farm that had
recently converted from milking dairy cows to boarding animals for other producers (Lake
Carmi).
In Vermont and across the Lake Champlain Basin, the extent of tile drainage systems and their
potential impacts on water quality have not been adequately assessed. A previous study by
Stone Environmental (Stone) for the Lake Champlain Basin Program in the Jewett Brook
watershed in Franklin County (Braun et al. 2019) revealed that subsurface drainage systems in
agricultural fields can discharge significant quantities of phosphorus (P). This project adds to the
previous work by measuring nutrient and sediment concentrations and loads in tile drainage
water in a second agricultural area, Addison County, and comparing these values with nutrient
and sediment concentrations and loads measured in tile drains in the Jewett Brook watershed.
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 ongoing agency nutrient reduction programs
focused on implementation of agricultural conservation practices in the St. Albans Bay
watershed and bring the St. Albans Bay phosphorus targets within reach.
In the first phase of this project, representatives of local, state, and federal government bodies
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
potential ways to avoid or minimize impacts to these resources. The resource concerns that
emerged as most challenging were 1) entrainment of fish (specifically larvae) in intake pumps;
2) potential impacts to aquatic organisms due to warming of the stream at the discharge
location; and 3) potential impacts to fish species recruitment due to alteration of the natural flow
regime in Jewett Brook and the Black Creek Wildlife Management Area.
Stone performed a comprehensive review of potential sites in the lower Jewett Brook watershed
for development of a treatment train facility. Two sites on the Dunsmore Farm on Dunsmore
Road emerged as most viable. Each site has advantages and disadvantages. A conceptual
treatment facility design is presented for each site. At this juncture, we believe the Dunsmore 2
site is the best option, because it is more proximate to Jewett Brook and its soil, slope, tree
shading, and access conditions are more favorable. The primary resource concerns could be
addressed in the design and operation of a treatment facility located at the Dunsmore 2 site.
Operating the facility only when flow conditions are suitable will minimize impacts on aquatic
biota.
Assuming seasonal operation (spring and fall), Stone estimates a median total phosphorus
removal rate of 286 kg per year (631 lb./yr) for the proposed Dunsmore 2 Treatment Train.
Using ballpark cost estimates, we predict the cost of P removal at this facility will be about $800
per kilogram.