Reproduction d'un article du
St. Alban MessengerMonday September 18, 2006
Rock River's impact sinking lake quality
Area watershed ranks with Lamoille among top pollution sources
BY NAT WORMAN
HIGHGATE -- The 50 square miles of the Rock River watershed delivers as much phosphorous to Missisquoi Bay as the 900 square miles of the Lamoille River watershed delivers to Lake Champlain.
That's part of the picture Brian D. Jerose of Waste Not Resource Solutions, of Fairfield, and Kristin Underwood, geologist of South Mountain Research & Consulting, Bristol, will paint for area residents at a meeting at the Highgate Municipal Building tonight at 7.
It's one of the watersheds in which they all live. Pike River is another, and both are woven into the Missisquoi Bay watershed. At work everywhere, is flowing water and moving soil.
The Rock River watershed has been getting the closer evaluation, however.
"Of the 15 reaches of the Rock River, we did 12 by foot and three by kayak. This is a phase two assessment, actually out in the field. Phase one is review of maps and other data, through remote sensing, to determine which reaches are likely to have the highest impact," Jerose said when reached by phone Sunday.
A "reach" is a segment of river that has the same characteristics. The impact is about what the river carries into Lake Champlain and how it affects water quality there.
Rock River rises in the hills of Franklin, flows through two Quebec townships, and then through Highgate into the Missisquoi Bay.
Jerose said, "We are tasked with the identifying sources of sediment and nutrients. Where rock river enters Missisquoi Bay, there is a site of algae bloom after rain storms and a brown flume of turbid water carrying the phosphorous."
Phosphorous makes algae grow fat, thick, and poisonous. When you see the brown, that's clay soil.
Since the phosphorous molecule clings to soil particles, erosion is the most common way of moving the phosphorous from the every section of the watershed into waterways. "It is not a true chemical bond," Jerose said.
Why does the Rock River watershed produce phosphorous at such a prodigious rate?
Jerose: "To answer that question is one reason we?re out there looking. We have some theories which we are trying to test further. One likely reason is that Rock River watershed was under the old Lake Vermont which formed clay soils that formed on lake beds."
He added, "The second reason, is that when clay soils go into a waterway, they tend to stay in suspension, rather than settle out, like a grain of sand or gravel. So any muddy water we get, say, below the pond at Brown?s Corners, tends to make it all the way to the bay."
Finally, this watershed delivers its disproportionate share of phosphorous because of land use, that's the impact that Jerose will explain to landowners and town officials tonight.
"The farm practices in this watershed are not notably different than anywhere else, but because of these clay soils, any bare slope is prone to soil loss," he said.
Though he has talked with landowners as he and Underwood have worked on assessment of the river and its watershed, tonight's meeting launches him on the third major phase of his project: working with landowners and stakeholders. The job now is to reduce the phosphorous loading by erecting buffers of natural growth. Funds will come from four state, and two federal agencies.
Part of the plan to is to work with towns to fund "Better Back Roads" projects to reduce the soils that rain and wind sweep off the roads into waterways.
"My job now will be to find the funds and technical assistance for those landowners who want to proceed with conservations projects that fit their needs, and make sure these projects will reduce the phosphorous load," Jerose said.
It's a big job. There are some 60 landowners in the watershed and he hopes to have conversations with all of them, and then spend most of his time with those he expects will show interest, about 20.
"This is a voluntary approach," he said.
How do you keep score to tell to what degree phosphorous is being reduced?
Jerose said, "There are different ways to keep score in a watershed. We're using the guideline of the river management program, called geomorphic assessment protocols. We are documenting the channel itself, its position in the valley and flood plain, the adjacent land use, constrictions from roads and culverts where the channel has been straightened, points of erosion and a whole host of other things. We take GPS locations, type of soil, and other particles in the stream bed."
Meanwhile, the battle will continue to make the Rock River watershed behave, an effort that will require more than studies, but calls on watershed area residents to do their parts, too.
RAPPEL -- La qualité de l'eau de la rivière de la Roche est aussi qualifiée de
très mauvaise par le ministère du Développement durable, de l'Environnement et des Parcs : voir l'
Indice de la qualité de l'eau dans le bassin versant de la baie Missisquoi.
