Wastewater

sandymcruer

Chinook Smolts in the Somass Estuary

A couple of weeks ago I was watching Global News at Six. A story about the future of the Squamish Spit came on. As I watched, I realised that they had exactly the same issue that we have here in our estuary with respect to Chinook salmon smolts.

In their case, a long narrow berm of fill was built out onto the mudflat of the Squamish River many years ago. It was to serve as part of a coal port that never materialized. The trouble with it is that this “Squamish Spit” separates the river that salmon smolts descend, from the estuary the estuary where they adapt to salt water. For salmon, especially Chinook Salmon, estuaries are critical habitats. Chinook Salmon more dependent on the estuaries than any other salmon species .

Conservationists have long recognised the situation and have called for the berm to be removed. But they are opposed by the Squamish Windsports society who regard their access to the winds of Howe Sound as “Canada’s Premier Kite-boarding Location. It looks like the windsports society is not going to win this one and that the spit will be breached to allow the smolts access to the rest of the estuary.

Chinook smolts must swim out around the end of this spit to enter the estuary,

It you substitute a couple of lagoons for the spit, you have the same situation right here in Port Alberni. All the Chinook Salmon smolts have to travel out into the inlet, around our wastewater lagoons and Johnstone Island.

The Alberni Valley Enhancement Association was able to secure funds to conduct a study of juvenile Chinook use of the estuary and confirmed a similar situation exists here at the mouth of the Somass River.

From the report: “Much of the estuary’s eastern shoreline (river-side) has been hardened through industrial, commercial and residential development, and much of the western estuary (i.e., Phil’s Bench area) has been cut-off from direct river connectivity by historic diking and channel-filling practices. Salmon fry and smolts attempting to rear in central and western reaches of the estuary must now migrate around the south end of Johnstone Island (which is no longer an island), and move passively or actively back on-shore in order to find suitable habitats. Given their relatively small size and limited swimming ability, it is problematic whether a majority of naturally-spawned Chinook fry can successfully complete this journey each spring.

So the AVEA recognised this situation and secured funds to replace a part of the access road between the ponds with a small bridge. However, it was recognised that the wastewater effluent from the old pond, that currently empties into the river would then also flow into the lagoon and ruin the water quality. So a dam was built as a temporary solution until the new wastewater plant was completed. The new plant discharges underwater 800m out into the harbour.

I mentioned that the bridge is a small one. Indeed it is. It is only 4 or 5 m across. The other two bridges over flood channels to the are almost twice as big.

The small bridge between the two lagoons.

Unfortunately the design of the new lagoon didn’t include a longer bridge, or another bridge. There is room to build one, but the opportunity to do so has likely been foreclosed. There is some hope that some of the money set aside for the decommissioning the old lagoon could be used to ensure that water flows freely under the bridge.

It is too bad that, unlike Squamish, this community doesn’t yet appreciate the importance of restoring the only part of the Somass Estuary that is relatively intact. It is only a third of its original size. No wonder the Chinook stocks are struggling.

References: The Importance of Estuarine Habitats on Anadromous Salmonids of the Pacific Northwest: a literature review. page 7.

What is the future of the Squamish Spit

Squamish Windsports Society proposes municipal park at Spit launch site

Somass River Estuary ‒ Juvenile Chinook Salmon Habitat Use Pilot Study ‒ Year 2 (Spring 2014)

sandymcruer

A Wastewater Tour Not Wasted

The Estuary of the Somass River is a very special place. It has been part of the lifeblood of this valley since time immemorial. And in a time when the salmon populations in this river are at historic lows any construction activity occurring within the remaining 30% of the original estuary should of concern to every citizen of the valley, including this one. Admittedly, it is late in the game to be taking such an interest, I still thought it would be a good topic to investigate.

 A week ago, Jim Wright and I met Ken Watson at the gate to the road into the wastewater treatment plant under construction on the Somass Estuary. He is the Acting City Engineer. For those who don’t know, Ken has spent most of his career with the City, mostly as the City Engineer, and Chief Administrator. After retirement he was asked to return to act temporarily as Engineer until a permanent one was in the job.  So we had an experienced guide to give the tour of the new wastewater treatment plant.

These hoses or booms pump air down into the weighted diffusers, or bubble-makers that oxygenates the water. Pond levels will rise and the bullrushes will die. Currently both bullfrogs and sunfish live in the ponds. But the winter ducks will very likely return and use the ponds. The gulls will use the new ponds too.

After donning our safety gear, Ken led us through the process. The current wastewater from the city flows through a very large pipe under Somass River and then underground to the currently operating lagoon. From there, a new pipe will extend from the old lagoon to the new lagoon and then into the new screening building. There the water goes through a ½ inch screen. It removes the hard bits like personal products, rags and other things that inadvertently end up in the sewer system. The screened debris ends up in the landfill. The water then goes into a much larger lagoon once used by the paper mill and bought by the city a couple of years ago for this purpose. It has eight times the volume that the current lagoon has. Watson says, “The new lagoon is more cost-effective, and effective”.

The UV building where the water is irradiated with ultraviolet light killing parasites, and pathogens. The 4 columns in the lagoon go 20 meters deep through thousands of years of river deposits. During the project an artifact was found that was 3500 years old. on those pylons a pump will be located that will draw water from the lagoon through to the UV building.

Across the lagoon are a series of floating booms. These will be part of the aeration system. Hanging from the booms, there will be 485 weighted diffusers which pump air bubbles up through the water. The oxygen is used by the fecal bacteria to render the “poop” harmless. I asked Watson ‘”What happens to all the organic matter? Doesn’t it turn to sludge?” The answer I got was that very little sludge was actually produced. Even the old lagoon dredge didn’t produce much sludge. In his career at the City he only remembers it being dredged 3 times. The organic matter is oxidized, that is “burned” by the bacteria releasing the carbon as carbon dioxide.

After the aeration treatment, the water is pumped into another building where it is irradiated with ultra-violet (UV) light. This kills all any pathogens, such as bacteria and viruses, left in the water. UV radiation uses no chemicals, and little energy. So it is highly effective.

The mill effluent lagoon was divided in half with this barrier. The cement culverts are to maintain an equal water level in each pond. This also gives you an idea of how high the operating water level will be.

Once irradiated, the water finished treatment. it is pumped 800 meters out into the inlet. Watson is confident that the water will easily meet the current standards set down by the Province and Federal Government. The effluent will be far cleaner than the current lagoon, which has needed replacement to meet current wastewater standards for many years.

This is one end of one of the aeration booms. The winch is to take up the slack when the water level is higher.

This has been a lengthy project. Construction has been ongoing for almost two years. Although it appears to be nearing completion, it is not expected to be in operation until early summer next year. Currently, the electrical power required to operate the system is being upgraded. Also 8 pylons now emerge from the pond. They are to support two pump stations needed to pump the water to the UV operation. Then the new sewage inflow needs to be attached to the existing inflow for the current lagoon. This needs to be done during a “fisheries window”, that is at a time where there is little impact on fish. That window is next spring. So by next summer after a couple of tests, it will be in operation.

Inside the screening building, Ken Watson is removing the cover of the screens.

The next step is deciding what to do with the old lagoon. Its construction took up highly productive salmon habitat. The obvious solution would be to re-establish it. However design objectives, methods and techniques are not as obvious. And it will cost money. Also, it is a popular place for the public to go for walks. So, some do not want to see the road access around this lagoon go away. Others want better connectivity for the smolts coming down to the ocean to linger in the estuary while they adapt to salt water. This would mean creating a gap in that road and also perhaps a defined channel for the water from the river to flow into Shoemaker Bay. There are a lot of alternatives. And the City has committed to a public engagement process before the design stage. That is expected to start in the New Year. So if you are one of those walkers, naturalists, birders or dog lovers who frequent the area, keep an eye out for public notices on this. And voice your opinion.

These screens won’t look so clean in a year or so!

Sources, and Background:

  1. Toprack Home Page Wastewater Engineering
  2. Wastewater Treatment Configurations and Process
  3. Ha-Shilth-Sa Infrastructure project aims to improve salmon habitat
  4. City’s Wastewater Treatment Plant Projected to Cost $37.9 Million