Wetlands in Parkland County

What is a Wetland?

A Wetland is land either seasonally, or permanently saturated or submerged under shallow water. Wetlands can be defined by the length of time they are submerged or saturated with water.

Figure 1. Diagram showing how a wetland works along with the benefits they provide.
Source: What is a wetland? — Ducks Unlimited Canada  

In Alberta, wetlands include peatlands, mineral wetlands, and constructed wetlands. Wetlands link groundwater, surface water, soil moisture, and weather patterns. Draining wetlands can have significant local impacts, including lowering the water table, reducing local precipitation, and creating greater temperature extremes.

Benefits of Wetlands

Biodiversity
Biodiversity is the variety of living things in an area, and higher biodiversity is more resilient and healthier. Wetlands are among the most biodiverse ecosystems in the world, with Canadian wetlands supporting over 600 species of plants, animals, and insects. Virtually all Prairie wildlife species rely on wetland habitat for at least some stage of their life cycle.

Carbon Sequestration
Globally, wetlands store approximately 30% of terrestrial carbon while occupying only 5-8% of the landscape. The plants surrounding wetlands capture and store carbon within the soil, removing carbon dioxide from the atmosphere. Conversion of wetlands to other uses releases significant amounts of carbon to the atmosphere.

Flood Reduction
Wetlands act as natural sponges, collecting, storing, and slowly releasing water which leads to a reduced risk of soil erosion, flood damage, and drought. Water naturally collects in the low-lying areas of the landscape, where it is then slowly released, soaked into the soil to recharge groundwater, or absorbed by plants. Wetlands provide significant flood-reduction benefits because they can store large amounts of water: a single acre of wetland can store over 1 million gallons of water!

Figure 2. A graph showing the difference in water storage ability areas with and without wetlands.
Image from: Aquality Wetlands 101 Course  

When wetlands are removed, increased flooding and erosion results. Studies have shown that when less than 10% of a drainage basin or watershed is made up of wetlands, significant peak flows can occur, washing large amounts of sediment and contaminants into waterways.  Flood protection increases with abundance and health of wetlands.

Groundwater Recharge
Water in wetlands infiltrates into shallow groundwater, and small amounts also reach deep groundwater. In addition, riparian plants transpire (“exhale”) water, causing hydraulic pressure that draws groundwater closer to the surface and maintains a high water table, resulting in better soil moisture. Undrained watersheds have significantly more moisture in the top 1.5m of surrounding soils compared to drained watersheds.

Filtration
Phosphorus retention is considered one of the most important attributes of natural wetlands and is key to determining downstream water quality. Phosphorus contamination from agricultural runoff increases algal blooms and turbidity and harms underwater plant growth in aquatic ecosystems. Wetlands are estimated to remove up to 92% of the phosphorus received from runoff.

Nitrates from fertilizers can cause eutrophication of surface water or leach into groundwater and contaminate drinking water sources. In one Alberta survey, 13% of sampled shallow wells had nitrate/nitrite levels above the guideline for human consumption.

Wetlands remove nitrogen from water through uptake by wetland plants and sediments, increasing the quality of groundwater. The ability of wetlands to retain water, and the biological functions that they support also lead to the natural die-off, predation, or entrapment of 80-90% of pathogens.

Conservation and Restoration

The Alberta Wetland Policy aims to minimize and mitigate the loss of wetlands in the province. Within the policy, Alberta’s high value wetlands are prioritized for protection. This value is based on their functions, rarity, and benefits. Wetlands are managed by avoiding, minimizing, and replacing lost wetland value.

The Alberta Wetland Replacement Program is a tool of this policy. This program works with municipalities and non-profit organizations to replace and restore wetlands in Alberta. Funds that have been collected to compensate for wetland loss can now be accessed and used for wetland construction and restoration projects.

If you would like to see a wetland in your area, email sustainability@parklandcounty.com or phone 780-968-8467.