Watershed Nutrient & Sediment Management Advisory Group

Watershed Nutrient & Sediment Management Advisory Group - Algae bloom looking towards Cootes Paradise

Started in 2014, the Watershed Nutrient and Sediment Management Advisory Group (WNSMAG) is an on-going initiative, comprised of a senior committee of decision makers that manages the findings of four separate task groups.

The Sediment Control on Active Construction Sites Task Group is focused on reducing sediment and erosion from construction sites through process audits and training. 

For the Urban Runoff Task Group, there are two similar task groups based on location. They are the Urban Runoff – Hamilton Task Group and the Urban Runoff – Burlington Task Group. Both are focused on reducing phosphorus and sediment through the expanded implementation of low impact development (LID) techniques, the updating of manuals, stewardship and training. 

There’s also a Rural Runoff Task Group with the same deliverables and they are expecting to report back to the advisory group in the Spring of 2017.

How does it relate to the Hamilton Harbour Remedial Action Plan (HHRAP)?

The work and findings of the four task groups essentially put the harbour on a “phosphorus and sediment reduced diet” through close monitoring and reporting. This is a positive step as less phosphorus will lead to fewer algae blooms. When you have increased phosphates in water systems, this higher concentration causes increased growth of algae and plants. Algae then tend to grow very quickly when there are a lot of nutrients available in the water. The problem is each alga is short-lived which results in a high concentration of dead organic matter that then starts to decay. This decaying process consumes the dissolved oxygen in the water resulting in hypoxic conditions. 

Without sufficient dissolved oxygen in the water, other plants and animals die off.

Less sediment will lead to less phosphorus as it is frequently attached to sediment particles. In addition, less sediment will also improve water clarity, allowing light to penetrate deeper into the water column. This improves aquatic plant growth and rebalances the fish community. This improves aesthetics for the public visiting the Harbour.

Low impact development (LID) techniques work to infiltrate flows at the source, where the rain falls, thereby reducing flows further down which prevents flooding.

How does it relate to the City of Hamilton's Clean Harbour Program?

In areas with Combined Sewer Overflow tanks, less phosphorus and sediment inputs into the water reduces the pressure on the infrastructure system. Many of the LID techniques will involve a reduction in flows into the water system which again reduce pressure on the infrastructure system as the tanks don’t need to hold this water.

Improving what comes into the harbour from the watersheds will complement the significant investments in infrastructure to combat eutrophication, which is the process by which a body of water becomes enriched in dissolved nutrients such as phosphates.

What is the return-on-investment for the residents of Hamilton?

In doing this work, this provides the residents of Hamilton with healthier creeks as well as improved conditions for Hamilton Harbour and Cootes Paradise marsh. It also provides for a much more pleasant looking environment for the residents to enjoy.

Algae bloom at Desjardins CanalAlgae bloom at Desjardins Canal