Algae in Cootes Paradise
On March 26th of this year, 30 mm of rain fell over Hamilton in just four hours. Our city’s Main-King combined sewer overflow (CSO) tank, just up the hill from Cootes, was overwhelmed, resulting in 12 million litres of urban runoff, contaminated with wastewater (which is stormwater and sewage) entering Chedoke Creek and then into Cootes Paradise. Several smaller CSOs also saw their overflows spill into Chedoke Creek and Cootes.
A Potent Mix
Most of the sewage composted quickly and settled to the bottom of the eastern end of the Cootes Marsh. Currents carried the rest to Hamilton Harbour. The nutrients in this messy mixture are potent fertilizer for growing plants, but the concentration of nutrients in sewer overflows are harmful to our ecosystems. Algae are the first aquatic plants to take advantage of this nutrient-dense buffet table.
Aquatic environments need nutrients and tiny algae plants that flow in the water, but the growth of excessive algae creates problems for the entire ecosystem such as reduced oxygen for fish, and stinky, ugly shorelines for people. Algae is a longstanding problem in our Great Lakes and certainly in Hamilton Harbour. Its reduction is a main priority of the Hamilton Harbour Remedial Action Plan.
Potent Mix + Shallow Water
This year almost all of Cootes Paradise is very shallow, currently less than 60 cm (2 feet) deep. Below average water levels allow the sunlight to penetrate the depth of the marsh directly to the algae species. The sewage compost mixed with the sunlight enabled the algae to respond and the overgrowth smothered other plants.
As the growth of algae progresses on the marsh bottom, pieces eventually tear off into chunks and these float to the surface of the water, buoyed by gas bubbles derived from its decomposition. These pieces of algae are then washed ashore to litter the banks of Cootes.
Blight & Duress
The abundance of algae is a blight on the natural beauty of Cootes Paradise and its ecology. It also reveals a natural habitat under duress from historical waste, ongoing spills, nutrient loadings, and runoff pollutants incoming from Ancaster Creek, Borer’s Creek, Chedoke Creek, and Spencer Creek. Deliberate, city-wide action is needed to fix things.
Abundance + Capacity = Harm
The resulting algae that you have seen in Cootes for the past few weeks would be naturally limited if it were not for an aquatic system that was already overwhelmed by contaminants from the surrounding urban environment. At issue is the abundance of nutrients being loaded into our waterways and the capacity of our existing infrastructure to keep up with a growing city and more extreme weather conditions brought by climate change. The 30 mm rain event on March 26th would have been considered a very rare occurrence 30 years ago. Today, this level of precipitation occurs multiple times each year.
Sources
The sources of these nutrients are numerous and both historic and contemporary.
The list of sources includes ongoing sewer spills from outflow sites, agricultural and industrial contaminants, and stormwater that picks up oils from cars, salts, and other pollutants running off a growing inventory of paved suburban roads and driveways, along with superstore-sized asphalt parking lots.
Once a Maternity Ward
At one time in our history, over 20% of Canada’s inland commercial fishery was sourced from the waters of Lake Ontario. In the early 1900s, over 30,000 pike used to swim and spawn in the waters of Hamilton Harbour and Cootes. This year, scientists have counted four at the Fishway.
Struggling for Oxygen
Fish, plants, and other creatures trying to live in the waters of Cootes are struggling to get oxygen. The overload of nutrients that enable the abundance of algae and the process of its decay consume much of the oxygen. That’s why catfish, carp, and goldfish are some of the sole survivors in these waters. Think of a child’s small fishbowl and the ability of goldfish to survive with access to only the oxygen above the water’s surface.
Act Today. Celebrate Tomorrow
The action that must be taken will not entail ribbon cutting. Any celebration will be down the road, long after the tenure of current elected officials from all levels of government.
The following list is not exhaustive, but an example of what we can do and what we must tackle.
A Watershed Approach
We need to lean into watershed planning in recognition that housing development at the headwaters is impacting the integrity of urban creeks and our Harbour. We can keep encouraging and supporting all of our water keepers, including the city of Hamilton, in their renewed efforts to work together and plan together.
Green Infrastructure
We need to get serious about permeability in our surface designs, encourage depaving opportunities in our neighbourhoods, demand energy efficiency in our built inventory, offer incentives for residential green infrastructure to soak up stormwater on-site rather than having it enter our sewer system, and get serious about native tree planting while doing more to protect our existing urban tree canopy, including trees on private property.
Long term Funding Resiliency
We need to pivot from band-aids to resiliency in our funding schemes. In 2020, the city experienced a total of 267 watermain breaks at a repair cost of $3.92 million. A more appropriate level of funding will allow us to invest and upgrade before the watermains break and it becomes an emergency. We simply cannot afford to starve our assets.
Figure 1:
City of Hamilton, 2021 Recommended Water, Wastewater and Stormwater Budget (FCS20073) November 23, 2020
Fairness
Unlike many other municipalities, Hamilton does not have a dedicated funding stream for our stormwater system. The chart below indicates a serious pattern of underinvestment. The righthand column is specific to stormwater.
Figure 2:
City of Hamilton, 2021 Recommended Water, Wastewater, and Stormwater Supported Budget Presentation, November 23, 2020.
A stormwater fee is a user fee that would charge large commercial, industrial and institutional properties for the stormwater runoff that comes off their properties into the public system. Right now we have an unfair system. Homeowners and renters are subsidizing stormwater runoff from these sectors. If these large businesses and institutions have to pay more for the stormwater they contribute they will have much more incentive to actually reduce runoff at source on their own properties. That will ease the capacity pressures on our system and help address sewage overflows.
The Urgency of Now
I know that talking about algae, nutrient loadings and stormwater treatment isn’t sexy and is unlikely to capture headlines or win votes. But if we really care about the legacy we are leaving our kids and grandkids, then cleaning up and restoring Cootes and our Harbour to the pristine jewels that they could be should be one of our highest priorities. Borrowing from Dr Martin Luther King Jr, we must summon the “urgency of now” in preserving and improving our natural environment.