Polluted Runoff Water
Polluted Runoff Water
As New Hampshire’s forested land is cleared for homes, businesses, roadways, and parking lots, the natural ability of the landscape to soak up melted snow and rain water decreases. Because of this, more runoff water travels across pavement and lawns, picking up pollutants on the way into our lakes.
The water quality of a lake is primarily determined by what flows into it from the surrounding landscape (the watershed).
Typical pollutants in runoff water include fertilizer, road salt, waste from septic systems and animals, and soil. Once in the lake, these pollutants degrade its health in many ways.
Over ninety percent of the water quality problems in New Hampshire’s lakes and rivers are caused by polluted runoff.
Watershed Pollution Types
Nutrient pollution is primarily carried into our lakes by runoff water that flows across the landscape, picking up fertilizer, animal waste, and eroded soil, which can all be high in nutrients. Nutrient pollution can also seep into the lake through surface water and groundwater contaminated by untreated wastewater from inadequate and failing septic systems.
Nutrients can also be mixed into the lake when shorelines and lake bottoms are disturbed by winds, wave action, and wakes produced by boating activities. Phosphorus pollution is harming many of New Hampshire’s lakes.
Chloride can be toxic to aquatic life and can foul waters used for drinking water supply.
This problem is increasing in severity. In New Hampshire alone, in 2008, 19 waterbodies were listed as being impaired due to chloride pollution. In 2020, 50 waterbodies were listed as being harmed due to chloride pollution.
Other Threats to Water Quality
Cyanobacteria
New Hampshire’s lakes have seen a record number of toxic cyanobacteria blooms for the past three summers. These blooms can produce toxins that make people, pets, and wildlife sick.
Climate Change
New Hampshire is experiencing increased precipitation, but it’s happening in fewer storms. This means that larger rainstorms occur after dry periods. As a result, the land can’t soak up all the rain at once, leading to more runoff water and nutrients entering our lakes that contribute to the growth of native and invasive plants, algae, and toxic cyanobacteria.
Invasive Species
Our lakes are home to many different kinds of plants and animals that are good for the lake. But, some species are harmful to our lakes.
by NHMB