Algae and weed management
Why is the water so blue?
As an alternative to pesticides, which can affect living organisms, a blue, vegetable-based dye is applied every year to a number of stormwater ponds for algae and weed control.
Algae requires sunlight to grow. The dye temporarily blocks sunlight from the algae, slowing its growth and reducing the occurrence of algal blooms on the pond. Other plants and wildlife, including ducks, geese and pets will not be harmed by the blue dye, but feathers and fur may be temporarily discoloured following contact with the water.
Algae and weeds are part of a natural wetland system. However, fertilizers from lawns enter the stormwater ponds when it rains giving the plants extra nutrients to grow beyond their natural size and population. When this excess material begins to decompose, it uses oxygen from the stormwater pond, which can be fatal to fish and other critters living in the water.
This algae and weed management program has been practiced in ponds around Sherwood Park since 2004.