ST. ALBANS — To end blue-green algae blooms in Missisquoi Bay the amount of phosphorous reaching the bay from agricultural fields will have to be reduced by 82.8 percent. That’s the target set by the federal government for agricultural fields in the final draft of pollution limits in the Lake Champlain TMDL (total maximum daily load).
In addition, the new phosphorous discharge target for the St. Albans City wastewater treatment facility is significantly lower than its previous permit and less than it is currently discharging.
The new targets were to be unveiled this morning, when the Environmental Protection Agency (EPA) announced the final draft. As with a previous draft, unveiled last fall, there will be a 30-day public comment period and public meetings.
The first such meeting will be held at St. Albans Historical Society’s Bliss Auditorium on Wednesday, Aug. 26, at 6 p.m.
The TMDL, which sets limits for phosphorous in Lake Champlain, contains aggressive phosphorous reduction targets for the two most heavily polluted segments of Lake Champlain – Missisquoi and St. Albans bays.
The State of Vermont also was set to unveil a phase one implementation plan this morning, outlining the steps that will be taken basin-wide, as well as additional measures to be taken in the Missisquoi and St. Albans watersheds.
To restore the quality of Lake Champlain’s waters, Vermont will have to reduce phosphorous loading in the lake by 33.8 percent.
The TMDL divides the lake into 13 segments, four of which are currently below phosphorous limits. Nevertheless, phosphorous reductions are included for those segments, since once it is in the lake, the phosphorous does move around.
Another six segments are very close to their phosphorous limits, with Missisquoi, St. Albans, and a portion of the south lake the farthest from their targets.
Phosphorous entering Missisquoi Bay will need to be reduced by 64.3 percent overall. Reduction targets have been set for each source of phosphorous in the Missisquoi watershed. They are listed below as percent reductions:
- wastewater treatment – 51.9 percent
- forest – 60 percent
- streambank erosion – 65.3 percent
- agricultural nonpoint sources – 82.8 percent
Missisquoi Bay is the only lake segment with a substantial reduction target for forested land. Overall, forested lands have the least amount of phosphorous runoff and are considered a boon for water quality. However, in the Missisquoi basin, the sheer volume of forested land makes it a significant source.
To address phosphorous from forested lands, the state is revising the accepted management practices for foresters with the goal of enhancing the standards for skid trails and truck roads.
To assist foresters in adopting those practices, the state intends to offer low interest loans starting in 2018, as well as taking advantage of existing funds available through the Natural Resources Conservation Services (NRCS).
In Missisquoi Bay, the state is also using LiDAR to map eroding and abandoned forest roads and skid trails to identify areas where erosion is occurring. In addition, Vermont intends to provide portable skidder bridges to foresters across the Missisquoi watershed.
To meet agricultural reduction target, the state is revising the Accepted Agricultural Practices and to make it clear the practices are required on all farms changing the name to Required Agricultural Practices (RAPs).
The revised RAPs include increasing buffers on corn fields to 25 feet from 10 feet, and cutting in half the level of erosion allowed on each farm. Ten foot buffers will be required for field ditches and gullies on fields will have to be stabilized. Livestock exclusion requirements will also be strengthened.
Small farms will be required to certify they are following the RAPs. The state has already begun inspecting small farms, with the sole inspector concentrating his efforts on St. Albans and Missisquoi bays. The state intends to hire three additional farm inspectors.
The state is in the process of visiting all farms in the Missisquoi and St. Albans watersheds and requiring the adoption of best management practices (BMPs) where inspectors believe they are needed.
Starting next year, the state intends to do the same in the south lake.
The plan also includes an analysis of nutrients from tile drainage on farms, and the possibility of revising the RAPs to address nutrients from tile drains. It does not include an analysis of the potential impact of tile drainage on streambank erosion.
Scientists in the Midwest have found that in clay soils water does not filter slowly into tile drains as it does in sandier soils. Instead, funnel-like macropores form in the soils, carrying rainwater directly from the surface into the tile drains. From the drains, the water goes directly into rivers and streams, increasing the volume and speed of the flow and destabilizing the streams. The Missisquoi basin has mostly clay soils.
Streambank erosion is a leading source of phosphorous in Missisquoi Bay. To address that erosion, the state is focused on expanding technical and regulatory assistance to help municipalities protect their floodplains, as well as establishing statewide river corridor mapping and using LiDAR to map flood areas around the state.
The state also intends to increase wetlands and floodplain conservation and restoration projects, as well as establish streambank stabilization practices for agriculture.
Overall, the state hopes to stabilize rivers and streams by giving them the room they need to stabilize on their own. However, in the Missisquoi Bay, the state will be actively looking for ways to stabilize streams such as reconnecting rivers and streams with their floodplains, intervening to stabilize streambanks where appropriate, and restoring wetlands.
St. Albans Bay
In St. Albans Bay, the reduction targets will likely mean improvements to the St. Albans City wastewater treatment facility in the not too distant future.
EPA has set a reduction target of 59.4 percent for phosphorous from wastewater treatment facilities in the St. Albans watershed. The other targets are:
- developed land – 21.8 percent
- forests – 5 percent
- streambank erosion – 55 percent
- agricultural fields – 34.3 percent
Overall, wastewater accounts for just over one-fourth of the phosphorous in St. Albans Bay, although wastewater treatment facilities supply just three percent of the phosphorous in Lake Champlain overall.
EPA has set a limit for the St. Albans facility of 0.2 micrograms per liter, which is less than the current average discharge at the plant of around 0.25 micrograms per liter. The previous permit limit for the facility was 0.5 micrograms per liter.
The same limit has been set for five of the eight wastewater facilities in the Missisquoi Basin – Enosburg Falls, Richford, Rock Tenn, Swanton and Troy/Jay.
The new limits are not per day, but apply to average limits over the course of the year. In other words, the facilities may occasionally exceed the limit as long as their average discharge remains at or below it.
Plants are not required to upgrade until they are at 80 percent of their permitted phosphorous discharges, and municipalities are to be allowed time to plan for upgrades.
Wayne Elliott of the engineering firm of Aldrich + Elliott previously told the city council the filters needed to improve the plants phosphorous reduction capacity would cost roughly $2 million.
The city is working with the state to test a series of approaches to phosphorous reduction at the facility.