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Challenges in Our Watershed

Buffer Zones

Buffer zones are areas of land, next to a waterbody, kept permanently in vegetation. Buffer zones slow the flow of water, trapping sediment, organic matter, nutrients and pesticides, which results in improved water quality. The plants in a buffer zone use some of the trapped nutrients for growth and provide habitat for various other species. Micro-organisms within the soil and vegetation of the buffer zone use the nutrients and organic matter. These micro-organisms can also transform some contaminants into less harmful compounds.

Buffer zones in PEI must be at least 15 meters wide, but larger buffer zones are encouraged, especially in certain areas.

Excess Nutrients/Run-off

Healthy Estuary

Anoxic Estuary


For most agricultural production, the addition of nutrients is a required part of the process of growing plants. Nitrogen in the form of nitrate is one of the key nutrients, along with phosphorous and potassium. Soil contains organic matter including nitrogen compounds, which are converted by bacteria into nitrates. 

When nitrates become overabundant in the water, whether it is groundwater, streams, or estuaries, it can cause problems. Nitrates are highly water-soluble, so if the level of nitrates available is greater than can be used by the plants, the nitrates leach into the groundwater. If drinking water has nitrate levels above 10 mg/L it can present health risks.

Nitrates also improve aquatic plant growth, but when aquatic plants grow too rapidly they can block sunlight from the plants below causing them to die. Dead matter consumes oxygen during decomposition, so with the decaying plant matter, the water can become anoxic.

PEI is originally composed of Acadian Forest species such as sugar maple, yellow birch, beech, red oak, with scattered white pine, red spruce, red oak, white ash and hemlock. Almost all of the original Acadian Forest was cut down to make way for agriculture by the 1800s.

Over the last two decades there has been an intensive effort by the two environmental groups in the watershed to reforest the riparian zone with Acadian Forest species. We have planted almost 21,000 native trees and shrubs since our group was established. Today, 43% of our watershed is forested.

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