Glossary

Algae
Small plant life that stays suspended in water. Growth of algae is a major threat to the clarity of any lake. 

Aquifer
An aquifer is a water-bearing bed or stratum of permeable rock, sand, or gravel capable of yielding considerable quantities of water to wells or springs. More>

Biochemical oxygen demand (BOD)
BOD is a measure of the amount of oxygen needed for bacteria to consume the organic components of wastewater.

Groundwater 
Ground water is water within the earth that supplies wells and springs; specifically : water in the zone of saturation where all openings in rocks and soil are filled, the upper surface of which forms the water table. More

Hydrological Cycle or Water Cycle
The water cycle is a complex sequence of conditions through which water naturally passes from water vapor (condensation) in the atmosphere through precipitation upon land or water surfaces and ultimately back into the atmosphere as a result of evaporation and transpiration 

Natural Buffer
A buffer is created when vegetation such as trees, shrubs and ferns grow around a wet area. Vegetation helps to trap and filter sediments and pollutants before they reach a body of water. 

Phosphorus
A basic element and nutrient that fuels the growth of algae. Common sources of phosphorus around the lake are topsoil, grass clippings, pet droppings, septic tank effluent, fertilizers and cleaning products.

Secchi Disc
A device used to measure clarity of water. Sebago's clarity is excellent, with an average reading of 33 feet.

Total Suspended Solids (TSS) 
TSS is a measure of matter suspended in water.

Two Mile Limit
An area at the south end of the lake where no bodily contact with the water is allowed. Signs clearly mark this area which is within two miles of the water supply intake. Preventing human contact dramatically lowers the level of coliform bacteria in the water. 

Water Table
The water table is the upper limit of the portion of the ground wholly saturated with water whether very near the surface or many feet below it -- called also groundwater level.

Watershed
A watershed is defined as an area of land that is connected by lakes, rivers and streams that drains into a large body of water. More

Wetland
When it rains, water flows downhill. It collects in natural basins. Transitional areas covered by shallow water are known as wetlands. Wetlands commonly serve as a drainage basin.