View live data from LEA’s Long Lake Buoy in the North Basin of the Lake from May-November
Long Lake is the second largest water body in southern Maine and is part of the Presumpscot River drainage. It connects to Brandy Pond and Sebago Lake, making it popular with water-skiers and boaters. Activities on the Causeway in Naples include trips on the Songo River Queen paddleboat, seaplane rides, windsurfing and para-sailing.
Long Lake supports a high quality black bass fishery and is one of the more popular lakes in southern Maine for bass angling tournaments. Other principal fisheries are landlocked Atlantic salmon, brown trout, chain pickerel, and white perch. Twelve other species also are present, including American eel, golden and common shiner, fallfish, white sucker, brown bullhead, burbot, lake and brook trout, pumpkinseed sunfish, yellow perch, and rainbow smelt. Each fall the lake is stocked with landlocked salmon and brown trout from the state hatcheries.
North Basin: The average Secchi disk reading for 2021 was 6.2 meters, which falls into the moderately clear range. The average total phosphorus reading of 6.1 ppb falls into the moderate range. The average deep water phosphorus value was not significantly above surface water phosphorus values, which suggests phosphorus recycling is not problematic. The chlorophyll average of 2.5 ppb falls into the moderate range. Long-term trend analysis indicates chlorophyll concentrations in Long Lake’s north basin are decreasing, total phosphorus concentrations are stable, and clarity readings are stable. The average color reading for 2021 was 26.3 SPU, indicating that water in Long Lake’s north basin is highly colored. Suitable coldwater fish habitat was present through June. As water temperatures increased and deep water oxygen was consumed, coldwater fish habitat became unsuitable in July
Middle Basin: The average Secchi disk reading for 2021 was 6.4 meters, which falls into the moderately clear range. The average total phosphorus reading of 7.1 ppb falls into the moderate range. The average deep water phosphorus value was not significantly above surface water phosphorus values, which suggests phosphorus recycling is not problematic. The chlorophyll average of 2.0 ppb falls into the low range. Long-term trend analysis indicates chlorophyll concentrations in Long Lake’s middle basin are decreasing, total phosphorus concentrations are stable, and clarity readings are stable. The average color reading for 2021 was 25.1 SPU, indicating that water in Long Lake’s middle basin is highly colored. Suitable coldwater fish habitat was present through mid-June. As water temperature increased and deep water oxygen was consumed, coldwater fish habitat transitioned to marginal and then unsuitable habitat in July. Unsuitable coldwater fish habitat persisted through September.
South Basin: The average Secchi disk reading for 2021 was 6.5 meters, which falls into the moderately clear range. The average total phosphorus reading of 6.3 ppb falls into the moderate range. The average deep water phosphorus value was not significantly above surface water phosphorus values, which suggests phosphorus recycling is not problematic. The chlorophyll average of 2.4 ppb falls into the moderate range. Long-term trend analysis indicates chlorophyll concentrations in Long Lake’s south basin are decreasing, total phosphorus concentrations are decreasing, and clarity readings are stable. The average color reading for 2021 was 26.8 SPU, indicating that water in Long Lake’s south basin is highly colored. Suitable coldwater fish habitat was present through late June. As water temperatures warmed and deep water oxygen was consumed, coldwater fish habitat transitioned to marginal in July and became unsuitable in August through September.
North Basin 2021 Quick Stats
Long Lake north basin’s surface water chlorophyll (ppb), phosphorus (ppb), and Secchi depth (meters) data comparison. Colored areas represent the long-term range of values, from minimum to maximum. Area thickness indicates frequency of measurements at that value. Area thickness increases as more measurements are reported at that value. The vertical black line represents the long-term average value. The large red dot represents
2021’s average value. The small red dots represent individual readings taken in 2021.
North Basin’s 2021 Average vs. Long-term Average:
Clarity: The North Basin’s 2021 average water clarity was within the ‘moderately clear’ range. The North Basin’s long-term clarity trend is stable, indicating neither deeper nor shallower Secchi readings over time.
Chlorophyll: The North Basin’s 2021 average chlorophyll concentration was within the ‘moderate’ range. The North Basin’s long-term chlorophyll trend is decreasing, indicating that there is less chlorophyll in the water over time.
Phosphorus: The North Basin’s 2021 average phosphorus concentration was within the ‘moderate’ range. Deep water phosphorus values were not significantly above surface water phosphorus values indicating that phosphorus recycling was not an issue for the North Basin in 2021. The North Basin’s long-term total phosphorus trend is stable, indicating neither more nor less phosphorus in the water over time.
Middle Basin 2021 Quick Stats
Long Lake middle basin’s surface water chlorophyll (ppb), phosphorus (ppb), and Secchi depth (meters) data comparison. Colored areas represent the long-term range of values, from minimum to maximum. Area thickness indicates frequency of measurements at that value. Area thickness increases as more measurements are reported at that value. The vertical black line represents the long-term average value. The large red dot represents
2021’s average value. The small red dots represent individual readings taken in 2021.
Middle Basin’s 2021 Average vs. Long-term Average:
Clarity: The Middle Basin’s 2021 average water clarity was within the ‘moderately clear’ range. The Middle Basin’s long-term clarity trend is decreasing, indicating shallower clarity readings over time.
Chlorophyll: The Middle Basin’s 2021 average chlorophyll concentration was within the ‘low’ range. The Middle Basin’s long-term clarity trend is stable, indicating neither deeper nor shallower Secchi readings over time.
Phosphorus: The Middle Basin’s 2021 average phosphorus concentration was within the ‘moderate’ range. Deep water phosphorus values were not significantly above surface water phosphorus values indicating that phosphorus recycling was not an issue for the Middle Basin in 2021. The Middle Basin’s long-term total phosphorus trend is stable, indicating neither more nor less phosphorus in the water over time.
South Basin 2021 Quick Stats
Long Lake south basin’s surface water chlorophyll (ppb), phosphorus (ppb), and Secchi depth (meters) data comparison. Colored areas represent the long-term range of values, from minimum to maximum. Area thickness indicates frequency of measurements at that value. Area thickness increases as more measurements are reported at that value. The vertical black line represents the long-term average value. The large red dot represents
2021’s average value. The small red dots represent individual readings taken in 2021.
South Basin’s 2021 Average vs. Long-term Average:
Clarity: The South Basin’s 2021 average water clarity was within the ‘moderately clear’ range. The South Basin’s long-term clarity trend is stable, indicating neither deeper nor shallower Secchi readings over time.
Chlorophyll: The South Basin’s 2021 average chlorophyll concentration was within the ‘moderate’ range. The South Basin’s long-term chlorophyll trend is decreasing, indicating that there is less chlorophyll in the water over time.
Phosphorus: The South Basin’s 2021 average phosphorus concentration was within the ‘moderate’ range Deep water phosphorus values were not significantly above surface water phosphorus values indicating that phosphorus recycling was not an issue for the South Basin in 2021. The South Basin’s long-term total phosphorus trend is decreasing, indicating less phosphorus in the water over time.
This project aimed to significantly reduce erosion, sediment and phosphorus export into Long Lake. The grant began in the spring of 2006 and conservation practices that reduce erosion and polluted runoff were installed at over 27 sites throughout the watershed. Roads, beaches and residential properties were worked on during the project. A Youth Conservation Corp (YCC) was also formed which installed best management practices on numerous residential properties.
A TMDL is a detailed watershed report with land use information and phosphorus loading estimates for a specific lake. The acronym TMDL stands for “Total Maximum Daily Load” and for Maine lakes it is used as a tool to assess and reduce phosphorus loading from within the entire watershed. Working with the Maine Association of Conservation Districts and Maine Department of Environmental Protection, LEA helped compile, organize and write a TMDL for Long Lake. The non-regulatory reports are intended to serve as a platform for future implementation work and watershed planning. It can also be used to compliment comprehensive planning updates. In addition to the land use inventory and phosphorus loading estimates, the reports contain water quality, fishery and soils information, a shoreline survey and recommendations for future best management practices in the watershed.
11 percent of soils in the watershed are type A soils. Type A soils tend to be well drained sands, loams, and gravels. When vegetation is removed and the soil is exposed they can be susceptible to erosion. Because they are often coarse with ample pore space, there is low runoff potential and water will not usually pool on them. These soils can be good places to site leach fields or infiltrate stormwater from a home or residence.
2 percent of soils in the watershed are type B soils. B soils have moderate infiltration rates and fine to moderate texture and soil size. They are usually made up silts and loams. Although not as well drained as A soils, they can also be good places to site leach fields and infiltrate stormwater.
58 percent of soils in the watershed are type C soils. C soils have low infiltration rates and typically have a layer that impedes the movement of water. These soils are made of sands, clays, and loams and are one of the most common soil types in western Maine.
3 percent of soils in the watershed are type D soils. D soils have a high runoff potential and very low infiltration rates. Soils with a high water table, clay or other impervious layer near the surface are typically D soils. These soils are often associated with wetlands.
2 percent of soils in the watershed are type C/D soils. C/D soils are a mix of these two soil types. They have fairly high runoff potential and low infiltration rates and often pool water.
The remaining 23 percent of the watershed is taken up by the lake.
