Archive for June, 2008

We Begin Suction Harvesting

Thursday, June 26th, 2008

In deference to the spawning habits of the resident fish (and the restrictions of our State permit) we wait each year until late June to begin suction harvesting.  The divers are still actually hand pulling the milfoil, scooping up roots and silt to remove the whole plants.  They then thrust the mass of root, silt, and plant into the vacuum hose, which sucks it up through the boat mounted pump.  It is spewed out of corresponding hoses into what we call the ‘trash rack,’ a sort of floating strainer which we can tow up the boat ramp and dump at the end of the day.

DEPLOYING THE HOSES FOR SUCTION HARVESTING

While milfoil plants are being fed into the hoses by two divers on the bottom, the other two stand in the trash rack and scrape the plants and fragments from the screen to keep it from clogging.

THE SUCTION HARVESTER AT WORK

The trash rack is a utility trailer equipped with an hydraulic dumper and fitted with styrofoam floats for buoyancy.  When full of wet milfoil it is very heavy.  We dump it daily when it is in use.

EMPTYING THE TRASH RACK ON A CHILLY MORNING

Divers in the Water

Sunday, June 15th, 2008

This is a Diver-Down flag. Scuba divers and snorkelers are required by law to display this flag when they are in the water.

Diving activities are not obvious to a passing boater. All that can be seen on the surface when the divers are working is a faint trail of bubbles. The evidence of their activity might look from a distance like a lone aluminum skiff sitting motionless on the water. If our divers are in the water, the flag shown above will be displayed on a short mast above the boat.

All vessels are prohibited from operating within 200 feet of a displayed ‘divers-down’ flag by Vermont law. All watercraft, including canoes and kayaks are required to obey this rule. Power boaters obviously pose a particular hazard to our divers, and are urged to give them a wide berth.

Unfortunately some boaters are unaware of or ignore this law. Our divers are performing a tiring and sometimes thankless job for us, helping to control an expanding nuisance. Please help them by oe as aware.beying the law yourself and mentioning it to others who might not be as aware.

Deciding Where the Divers Work

Saturday, June 7th, 2008

Frequently we are asked, “When will the divers be working in my area?”

Although this seems to be a simple question, a proper answer requires some understanding of Lake Fairlee’s milfoil problem and some of the constraints under which our program works. First, Lake Fairlee belongs to the State of Vermont, not to the lake residents nor to the towns in which it is situated. What our divers do to combat milfoil is subject to permits issued by the State, as well as being partially funded by a State grant. Therefore Vermont has quite a bit to say about how and where we remove milfoil.

The state pays for almost half of the milfoil program. Another 10% is provided by the three towns, and the rest by contributions from LFA members. Some lakefront property owners are able to be exceedingly generous, while others contribute nothing at all. We do not, however, make decisions about where to pull milfoil based on who gives and who doesn’t.

There is much more milfoil growing in the lake than our divers can remove in a season. They are limited by the length of the season and the amount of money that the foundation can raise. They are not allowed to begin suction harvesting nor deploy bottom barriers before the end of fish spawning season. Before the middle of May or so the milfoil is dormant, and “lying down.” In October the days get shorter and the water gets colder, but by then we have run out of money anyway. In recent years we have raised enough money to keep four divers and a boat person working until about the end of September. We hope to be able to do at least that well this year. These considerations all impact our choices.

THE DIVERS MEET IN THE MORNING TO PLAN THE DAY’S WORK

We make our decisions where the divers work based on the needs of the lake as a whole. We develop a plan early in the season based on a complete survey of the milfoil in the lake. We decide where suction harvesting and bottom barriers can be used to best effect, and make application to the State for those locations. This early plan frequently has to be changed as the extent of the milfoil evolves. Nonetheless these major decisions significantly affect each day’s choices.

Then each day we decide where to work, based on this ‘master plan’ and on the lake conditions that day. Generally we prefer to focus on one area until it is completely clear of Eurasian milfoil before moving on. Sun and wind can affect visibility under water, and can change from morning to afternoon. Planning deployment of our resources is an important and complicated process.

On the other hand, there are many areas of the lake that want our attention. Deciding between several similar patches can be a toss up. So it is only after weighing all these factors that the varying generosity of our contributors be considered.