From the Bridgton News:
By Roger Wheeler, president
Friends of Sebago Lake
The recent headlines in the Bridgton News, “Crisis on the Songo” about the choking milfoil takeover of this famous little river reminded me of a 133 year-old Bridgton News article about a gun battle that erupted at Songo Locks in February of 1877.
Apparently, Westbrook contingents unhappy with the withholding of water from Sebago Lake and ponds above in the watershed forcibly gained control of the Songo Locks dam as well as the Sebago Lake dam. The Bridgton News reportedly quoted the local humor that gunboats were necessary to patrol the Songo River to keep order. Calmer minds prevailed and the “lack” of permanent storage was remedied with an addition to the Sebago Lake dam.
Today, gunboats are on the Songo but they are armed with the finest river bottom vacuum hoses that technology can provide. The enemy is milfoil. The milfoil “crisis,” however, is only a symptom of a looming ecosystem catastrophe brought about by the present highly unnatural freshwater flow regulation of the Presumpscot River-Sebago Lake watershed. This crisis is related to the1877 Songo Locks gunbattle over who controlled the flow of freshwater and our lake levels.
Sebago Lake’s historic superior water quality and late 1800’s fishery was a direct result of the Westbrook powers’ 1877 defeat of the navigation interests for control of water flow. Prior to 1877 and up until 1987 Sebago Lake outflows were as uniform as possible throughout the year. They went as low as 10,000 cubic feet per minute (cfm) and as high as 200,000 cfm but usually 42,000 cfm was the average flow.
This created water levels that mimicked the natural seasonal cycle of lakes with the natural historic fluctuations and between the years variability. Due to droughts, perhaps once or twice a decade, water levels reached the lowest 10th percentile or about 7 to 8 feet below the dam. Consequently, with these variations in lake level the lower Songo River was a sandy bottom stream with diverse natural vegetation along its meandering shorelines and wetlands. The river was always changing course gradually as the sands were always moving down river to its delta in Sebago Lake. This uniform flow regulation allowed the conditions for maintaining the most diverse and successful ecosystem habitat and for maintaining the highest quality water.
In 1987 the Westbrook “interests” (SD Warren Co.) finally succumbed to the greed of new bonus winter hydropower profits and the clamor of the marinas and started withholding those “uniform outflows” in the spring, summer, and fall. The historic range of fluctuations disappeared as well as between years variability. The common lower summer and fall water levels permanently ended. The water level regulation now is strictly controlled to insure high water in warmer months. The lake level rule curve strictly requires reaching precise levels on certain days of the year. The lake is mandated to be 18 inches below the spillway on August 1st. Fluctuations up to six and one half feet of its former range on this August 1 date have been eliminated! What has that done to the Songo River?
The present highly unnatural lake regulation has provided the conditions in which milfoil thrive and out-compete native plants. Prior to the 1980’s, Songo River sands were constantly moving because of the fluctuating water levels. Native vegetation lined the river in the shallows. It was good spawning habitat for salmon and trout. Native plants had adapted to the seasonal fluctuations and variability. They do not survive well with the present, near-constant, high water levels in the warm months of the year. The higher lake levels caused accelerated erosion of the riverbanks. The Songo River is 20 to 40 feet wider than 30 years ago. This rich eroded sediment accumulates on the once former sandy bottom channel, fueling the milfoil growth.
The main river channel is deeper and straighter. The stream channel where kids and camps once played, swam, canoed, and picnicked on sand bars has been replaced with a flooded channel that is choked with milfoil and black with the organic deposition. Now, the wetlands of the Songo never dry out to allow dead plant debris to safely desiccate and decompose. This has changed the chemistry of the wetland and river bottom soils. Elements like phosphorus, once safely sequestered in the wetland and river bottom soils because of occasional oxygenated conditions, now are released from the new anoxic soils into the water column, harming the water quality of the lake and fueling the growth of the invasive plants.
The same unnaturally high water level regulation that is harming the Songo River ecosystem has also eroded and decimated Maine’s most outstanding inland beaches. One only has to compare pre-1980s photos with the present. The lake regulation is harming the water quality of Sebago Lake according to a 2007 and 2008 Portland Water District report. However, PWD is backpedaling mightily this year on the data analysis because it could lose its waiver for filtration, and this might double the water bills of greater Portland.
Moreover, the unnatural freshwater flows from Sebago Lake into the Presumpscot River, along with the other similar watersheds in Maine, are having profound harmful impacts on the coastal estuaries and Casco Bay. Thanks to the regulation we have now, there has been an 18 fold increase in Presumpscot River low- flow events from 1997 to 2009 as compared with the time frame from 1910-1986. The high flow events are much higher and at unnatural times of the year. The river-clogging milfoil is a symbol of an an interconnected ecosystem failure from the far upstream lakes of the watershed to the ocean.
If the Congress of Lakes Association, the Maine Department of Environmental Protection, and others that control the high water mindset allow good science to govern water flow regulation, then milfoil can be defeated. When the Songo River is restored to a sandy bottom stream by returning natural variable historic fluctuations and allowing natural vegetation reestablishment, the remaining milfoil will be controllable. The salmon and trout will return to the Songo River. With fishways again restored to the Presumpscot River as the law dictates and a return to natural fluctuations and variable water levels, we could once again see Bridgton News quotes about the Songo River, such as was reported in the spring of 1877 “that fishermen line the Songo” and “ten ten pounders is a good day’s catch”.
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