Stopping Milfoil in the Songo River

Opinion Column – Lakes Region Weekly
By Steve Kasprzak
Friends of Sebago Lake

The recent call to close Songo Locks to boat traffic by Peter Lowell, executive director of the Bridgton-based Lakes Environmental Association has been drowned out by boating interests.

Camp owners, your property values are being threatened by the refusal of State officials to close Songo Locks to boat traffic for the economic benefit of marina owners. It makes no sense to allow boats to travel downstream through the Locks and into Sebago Lake without being inspected. Some of these boats traveling through the milfoil infested Lower Songo River are bound to pick up milfoil and then carry it to their moorings in the shallow water areas of Sebago Lake.

After the drought of 1985, the marina community successfully lobbied for higher than normal lake levels for sustained periods, in order to prevent water levels from going more than 4 feet below the top of Eel Weir Dam from April 1 to November 1.

In the fifty year period prior to 1985, lake levels dropped 6 to 8.5 ft. below the top of Eel Weir Dam on average once every other year. It has not happened once since 1985. Eliminating the historic and natural variability in lake levels has prevented the Songo River from cleansing itself naturally.

In the past, when low lake and river levels were followed by a big rainstorm and/or spring run-off, the high flows in Lower Songo River would scour the river bed and carry off the vegetation and silt into the deep waters of Sebago at the mouth of the Songo River.

Boating interests have successfully lobbied the Maine DEP to establish a lake level management plan which would prevent these natural low water levels. In 1997, Maine DEP advocated, and the FERC approved, a lake level plan which has eliminated the historic and natural variability in water levels.

These folks got what they asked for, and they should pay the bill to dredge the river or ask the State to amend the lake level plan, so the river can once again cleanse itself naturally! Not only has the lake level plan prevented the River from cleansing itself naturally, it has accelerated shoreline erosion in the river from boat waves.

Downstream from Songo Locks the average spring and summer water levels in Lower Songo River are now one to two feet higher than normal. The waves from the 70,000 plus boats trips through the Locks are attacking the River’s shoreline at levels that in the past were accessible to wave action only a few weeks of the year, instead of 4 to 5 months. This has accelerated the historic rate of shoreline erosion and washed phosphorus laden shoreline soils into the river. The phosphorous is a nutrient and promotes milfoil growth.

In the early 1990’s milfoil was discovered in the Lower Songo River. With over 70,000 boat trips annually through the Locks, it should have been closed then and stayed closed until the milfoil had been eradicated. There are now over 25 sites in Sebago of rooted colonies of milfoil identified by Portland Water District in their 2008-2009 Annual Watershed Control Report. All of these areas are in shallow waters and a return to the historic low lakes levels, 6 to 8.5 ft. below the top of the Eel Weir Dam, would help to eradicate the milfoil in these areas. Low water levels in the fall would allow heavy frosts to kill these plants.

Low draw downs of water levels are an effective and economical way of ridding a water body of nuisance plants. By eliminating the historic and natural variability in water levels on Sebago Lake and Lower Songo River, the State has provided ideal conditions to promote the growth and spread of milfoil throughout Long Lake, Brandy Pond and Sebago.