Presumpscot River A Plan for the Future Cumulative Impacts to Environmental Conditions on the River and its Shorelands dams). Orders from the Massachusetts How Has Use of Legislature in 1735 and 1741 required that any dams constructed on the river provide the River, and passage for fish. In the 1840’s concerns were Concern About raised over pollution of the river with bark Impacts to the River, and sawdust; in the 1850’s the paper industry Changed Over Time? was established on the river, and a number of other industries including woolen and textile Original accounts and archaeological mills, iron works, and a gunpowder mill findings on the Presumpscot report it to have added to the pollutant loading of the river. been a rushing river with many falls and For the next 100 years, industrial uses of the rapids; abundant fish life, including sea-run river were pre-eminent over other uses. species such as Atlantic salmon; and a Native American population (the Rockomeecook By the 1950’s the condition of the lower tribe of the Abenakis) living largely off the river was similar to most rivers in the river’s bounty, supplemented by corn developed northeast -- it was heavily polluted fertilized with fish caught at the river’s falls. and its primary value was as a conduit for waste. The culture of environmental The Presumpscot has a rich history. The consciousness that grew in the 1960’s, led to river was settled early in Maine’s history (the passage of the Clean Water Act and marked first dam was constructed at Smelt Hill in the reductions in water pollutant discharges by early 1730’s). The power and water supplied the 1970’s. While industrial and municipal by the Presumpscot were fundamentally treatment plant discharges to the river have important to the early development of the been dramatically reduced since the 1960’s, area. Without the river there would have nonpoint sources of contamination from been no mills and little development in the development and other land uses in the area. The Presumpscot was the site of watershed have increased. Maine’s first pulp mill, first hydroelectric project, only significant canal, and largest Interest in reclaiming the river was given a gunpowder mill. boost in 1992 when the Maine Department of Inland Fisheries & Wildlife undertook one of The impact of this development on the river its most successful efforts to reestablish a has been significant. No other river in Maine trout and salmon fishery in the upper reach of has virtually all its hydraulic head captured the river, below Sebago Lake. More behind dams. recently, the removal of the Smelt Hill Dam at head-of-tide, and cessation of the While use of the river for power and waste Westbrook Mill's pulp operation have disposal were viewed as a normal part of combined to improve the condition of the economic development at the time, the lower river and air quality in the area. As in impacts of the dams to the river's fisheries the past, this has given rise to a new set of have been a concern since the 1700's. It was competing interests, which are being the site of one of the first serious disputes addressed by this planning effort. over water rights in Maine (fish versus Page: 4 How Have Water Resources Been Changes in Water Quality Impacted Over Time? Because the basin was originally almost Altered Flow Regimes entirely forested, the original water quality naturally occurring in the Presumpscot River One of the most significant changes to the was in all likelihood very similar to that in natural river, dramatically altered hydrology, Sebago Lake, its source. resulted from controlling flows from Sebago Lake, and the development of dams and The cumulative impacts of waste discharges, impoundments on the river. This changed watershed development, and damming of the both the flows and character of the river, and river are quantifiable. Changes in water altered water levels on Sebago Lake. This quality include: analysis addresses cumulative impacts to the • Increased Total Suspended Solids river, but does not address changes to Sebago • Increased Dissolved Solids Lake. • Lowered Dissolved Oxygen Naturally occurring flows were undoubtedly • Increased Bacterial Levels more variable than flows that have occurred • Shift to Pollution-Tolerant Aquatic with regulation by the dam at Sebago. The Organisms figure above compares a typical hydrograph • Elevated Temperature of flows in the Presumpscot River at Westbrook with a hydrograph for the Ossipee Changes in Aquatic Habitat River, a comparably sized river with significant headwater lakes. This In the Presumpscot, the community of comparison indicates that the principal effect aquatic life has been adversely affected by of the flow regulation at Sebago Lake has cumulative impacts in the river: been to augment low flow periods. In sedimentation, warming, and creating addition, the hydrographs suggest that flow impoundments. After the historic removal of regulation also moderates high spring flows, the Smelt Hill Dam, over half of the river and tempers the effects of summer storms remains impounded. (the Presumpscot River is less flashy in the summer). How Have Estuarine Resources In addition, current velocities have been Been Impacted? decreased by the dams in places along the river; these dams have largely converted the Salinity river from free-flowing to a series of impoundments. It is unclear what estuarine species are benefited or disadvantaged by the existence of more stable fresh water flows to A Comparison of Existing Flows on the Presumpscot River with the Ossipee Presumpscot estuary, but it is clear that the River, an Uncontrolled River in the Adjacent Saco River Drainage system is different (more stable, less 5000 dynamic) than it would be under natural 4500 conditions. in 4000 3500 Chemistry of Estuarine Sediments cond 3000 scharge r Se i The Presumpscot River estuary is a large pe t 2500 depositional area where fine-grained an D e 2000 c Fee sediments carried downstream by the river i y M b il 1500 u a are accumulating. The fine-grained C D 1000 sediments of the river’s estuary have 500 moderately elevated levels of metals and high 0 levels of PAHs (polycyclic aromatic v c n b r r y n g p 0 De Ja Jul Se 994 No Fe Ma Ap Ma Ju Au p 3 hydrocarbons). Also the estuary has the . 1 Se ct O highest levels of dioxins and furans found in Ossipee River, Cornish Presumpscot River, Westbrook Casco Bay. USGS Data, 1994 Page: 5 Volume of Sediments How Have River Fisheries and Aquatic Life Been Impacted? The volume of coarse sediments reaching the estuary has been reduced by dams, while the Historical documentation of the fishery noted volume of fine sediments has been increased that “The Presumpscot is a … rapid river … by discharges and erosion in the watershed. frequented by salmon, shad and alewives, but seems to have been best adapted to salmon” Estuarine Water Quality and that salmon ascended the river to Sebago Lake and beyond (United States Commission The extent of eelgrass beds is often used as a of Fish and Fisheries, 1887). positive indicator of estuarine water quality. A 1993-1995 eelgrass mapping project Major changes to the fish resources of the undertaken by the Maine Department of basin include: Marine Resources (MDMR) did not detect • blocking (by dams) of fish passage for the presence of eelgrass in the estuary of the anadromous (salmon, shad, alewives, Presumpscot, a sign of a degraded condition. etc.) and catadromous (eels) species; DMR has estimated that if access were Estuarine Animals restored for 3 species (shad, alewives and blueback herring) that fish runs Pollution traveling downstream with the river totaling approximately 634,000 to has impacted estuarine organisms. In 1991, 786,000 fish could be supported by the the Maine Department of Environmental river; Protection data indicated that dioxin, a • fragmentation of habitats as a result of carcinogen, was present in soft-shelled clams dams on the river; in the estuary in significant amounts, • a shift from fast moving coldwater presenting a cancer risk of one in one riverine habitats to a series of slower million. moving impounded areas (15 of 17.5 miles of the original river above the Eliminating the runs of sea-run fish and Cumberland Mills Dam remains reducing the runs of American eels (a species impounded). This change favors fish that lives in fresh water and spawns in the species such as bass and panfish at the ocean) has impacted the estuary as well as expense of native salmonids; and the river. Runs of approximately 34,500 to • deterioration of water quality 136,000 adult American shad and 150,000 to (including depressed dissolved oxygen 200,000 adult alewives, and 450,000 conditions) resulting from industrial blueback river herring potentially could be and municipal discharges. restored to the river. If these potential runs develop, hundreds of millions of juvenile How Have Threatened and shad, alewives and bluebacks would be Endangered Species Been hatched in the river each year and tens of millions would migrate out of the river each Impacted? year. The yearly migrations of these adult Impacts to threatened and endangered plant and juvenile fish would make the species inhabiting the Presumpscot River Presumpscot River estuary and Casco Bay corridor include loss of habitats, particularly more attractive for a wide variety of floodplain forests as well as reduction in the predators including, but not limited to, productivity of these areas. Two plant species kingfishers, great blue herons, osprey, bald identified by the State as threatened or species eagles, striped bass, and seals. Researchers of concern have been observed and two others on Delaware Bay concluded that restoring reported historically.