3060357-poster-1280-keeping-secrets

This topic is under the radar which is probably why most people are not more indignant that in a city that prides itself on being green, sustainable, bikeable and smart we have a very very dirty secret~we don’t separate out our liquid garbage.

Think of it~we separate green waste from garbage, we compost what we can, and we are all educated on what to put in the blue recycling box. But few  people know  what the implications of a combined storm and sanitary sewer are to the environment. It just sounds like something that is mundane and boringly municipal. But what it really means is that when a combined sewer overflows, it is spilling untreated excrement into Vancouver’s surrounding water sources.

When I worked as the health planner for Dr. John Blatherwick the City’s Medical Health Officer, the separation of the combined sewer system was the first thing to be further delayed in any civic budget process.  Back in the 1980’s it was assumed that the entire city would be under a separated sewer program by 2020. But in checking on the city’s website that goal has been pushed back thirty years with  “We are working toward the Province of BC’s environmental goal to eliminate sewage overflows by 2050″.

When beaches are closed due to high coliform counts there is a public level of indignation that we need to do something to stop that. And there is-by finishing up the installation of a separated storm and wastewater sewage system that keeps getting delayed for other priorities.

While some of the city has separated storm and wastewater sewers, the parts that don’t have catchment water and liquid waste travel to the sewage treatment plant in one sewer. If there is a big rain event, stormwater can overwhelm that single pipe system, which means that untreated excrement overflows into water sources like False Creek.

As reported by Global News Park Board Commissioner John Coupar and City Councillor Sarah Kirby-Yung both tabled motions for the city to get serious about fecal waste outfall and to set up a ten year deadline to install sewer separation universally across the city

Councillor Kirby-Yung pointed out that 674,000 cubic meters of raw sewage ended up in False Creek from just one of the five overflow outlets the combined sewer has in the creek. As John Couper observed : “Presently we’re [replacing about] 0.6 per cent of the system every year, and right now 50 per cent of the city is separated. On the present timeline, we won’t even make it by 2050.”

In a city that is densifying the beaches and waterfront areas should be a public amenity for everyone to enjoy.

As Coupar bluntly concludes: “I think it’s pretty bad in 2019, especially for a city that considers itself green, that we can’t protect the city’s water more.We’re such a water-based city … and it’s time we have a hard look on this to see what we can change.”

How do we make this important priority matter?

From the City of Vancouver here is the list of which neighbourhoods have the separated sewer system, and which neighbourhoods will get this system by 2020. Note that Dunbar, Kerrisdale and Sunset are some of the neighbourhoods not yet scheduled.

From the City of Vancouver: we have a separated sewer system in the following areas:

  • Downtown
  • West End
  • Fairview
  • Hastings
  • Killarney
  • Mt. Pleasant
  • Renfrew
  • Burrard Inlet and Fraser River shorelines

By 2020, we plan to install separated sewers in:

  • Grandview
  • Kitsilano
  • Point Grey
  • Shaughnessy
  • Sunrise

 

no_swimming-1503506223-9987_1-1528982982-6644Images: Cdn20 & FastCompany

Comments

  1. The city is engaged in a 20 year program to separate the systems at a cost of over 10 billion. It would be a more sustainable strategy to insist on infiltration on lots and install rain gardens on streets to dramatically limit storm water caused overflows. New York City is pursuing this approach.

    1. @Patrick, why not do both … there will be big storms that will overflow that strategy, and these storms will get more frequent, and the infrastructure in question is getting older anyway, so replacement for replacement’s sake, as well as to upgrade, seems to make sense.

      Why pose the solutions as mutually exclusive? (just like we can add housing at UBC AND have a subway … we don’t need to always think zero sum)

          1. Considering the assessed value of properties in Vancouver has more than doubled in the last years, and the taxes have verymuch not doubled, I’d say not very.

            Vancouver’s taxes are low both as a fraction and as an absolute dollar figure compared with many peers both locally, and across the country. We can afford to tax more to both make pretty and actually separate poo.

  2. I agree with Patrick for rain gardens on streets. Seattle has been doing this very effectively, and the result is beautification of the public realm as well as less expensive stormwater treatment. But Ian is also correct: there’s a much stronger case for doing both. And why stop there? Are there other options?

  3. My comment is premised on taking the same budget, or less, and doing something more sustainable and also beautiful at the same time. I dont think tax dollars are infinite.

  4. When I read comments on building raingardens, especially on urban streets where land is severely constrained, for the purpose of infiltration and beautification, the first question I have is, Where is your geotechnical feasibility assessment? And, How fat is your maintenance and replacement budget?

    NYC is NOT rainy Metro Vancouver which is underlain by 10+ metres of hard glacial till that sandwiches and pressurizes an aquifer between it and the sandstone below. The till is often just 1 metre below the surface and overlain with an abundance of dense, low-permeability silt-laden soil.

    In 2009-10 I helped manage an outdoor amphitheatre project that was designed to accommodate 12,000 people. We were warned in no uncertain terms by the geotechnical engineer to not puncture the till below 1.5 metres from the surface because the ancient aquifer will then continuously overflow and erode the landscape for “10,000 years” (her words). An adjacent arts centre did puncture the till with its shallow parkade and the installation of a full drainage system below the slab and large diameter catch basins at one exposed corner, all connected to the city’s storm sewer system, became necessary. The flow in the drains is phenomenal, even at the end of a very hot+ and dry summer.

    Deep interceptor trenches with subsurface drain systems are a common thing all over the Lower Mainland, especially at the base of slopes that were cut into the till. Experiments with rock-filled drainage pits routinely fail in winter, overflowing and eroding park and other urban land and requiring replacement with standard catch basins and storm sewer connections.

    As mentioned, most Vancouver land is underlain by a layer of compacted light brown silty sand 60-150 cm below the surface sitting on the till, rendering even the cutest, award-winning raingarden, the kind that gives some designers and planners momentary palpitations of delight, become ineffective mud pits after the first rains of fall. In reality, the awards are soon so much forgotten candy floss as the specified plants are overtaken by native plants or grasses, invasives like blackberry and the Godzilla of them all, Japanese knotweed, which has very stringent treatment and removal procedures that will ruin the design intent and blow every maintenance budget. Moreover, they are a trap for garbage and are mighty inconvenient if you step in one in soggy November when so brilliantly placed between the road and property line and next to your front walkway. And these are supposed to be built on every street city-wide? Hmmm.

    So what does work?

    * Large downstream wetlands: Most cities did not culvert their salmonid streams as did Vancouver and have storm sewer inputs. Burnaby for example, has done an excellent job protecting these streams and enhancing them with further daylighting where possible. Byrne Creek drains the entire SE quadrant of the city, and to treat stormwater the city Engineering Environmental Services built a very large artificial wetland at the base of the south slopes where the stream enters the flats. It was expensive, and requires expensive maintenance, but it is very effective in cleaning and calming the water. They also very rich in wildlife. Moreover, if there is a toxic spill into the creek upstream, it can be contained very quickly in the confined wetland.

    * On-site storage. These can be 1,500-5,000 litre cisterns placed under the surface to capture roof runoff from houses, to be used in home gardens. Also 100,000-300,000 (or larger) litre cisterns placed under the surface in some parks to collect storm runoff from an entire neighbourhood (focus on roofs) used for irrigating park landscapes. If filtered and treated with UV light, it could be used as secondary irrigation for residential gardens and toilets.

    * Grey water recycling (tubs and showers only), with filtration and UV treatment to charge a grey water plumbing system leading to toilets, which will reduce the potable water usage by ~15-25%. Residential scale only in existing cities, but can be expanded to community-wide in new towns or large-scale developments with a central collection / distribution, storage and treatment system.

    * Very large biolswales with enough detention capacity to prevent overcharge from the most severe storms. Must be fenced for safety in public spaces, like parks.

    In a city that needs to densify all over, monkeying with narrow patches of precious and increasingly confined land for raingardens is ridiculous. More paving will be necessary. Above is a list that outlines ways to remediate the higher volume and speed of stormwater without creating a landscape of ugly shallow ditches on our streets.

    1. Additionally, there is no foreseeable reason why fire suppression systems (hydrants, indoor sprinklers, standpipes) cannot utilize stored and filtered mix of storm and grey water. Backflow prevention devices will be necessary to prevent the intrusion of grey & storm water into the potable water delivery system. This is water conservation at a much deeper level of sustainable urbanism. Raingardens are Mickey Mouse when realistically trying to deal with the reality of urban water use on a warming planet by reducing the per capita usage through recycling, and remediating the higher flows during winter storm events through detention and capture.

  5. I’m not making this comment because I don’t think the plumbing needs to be fixed, I hope we do that faster than 30 years and the alternative ideas discussed in the comments are intriguing. However, isn’t the coliform problem at the beaches due to geese? It’s been months since the last heavy rain after all.

    1. How would those rain gardens handle last night’s gully washer? They can absorb slow steady rain, not sheets of it.

      And agree with Anthony also, there’s another reason for the poo water besides the sewer separation … Birds part, boats in the harbour part, sewers part, likely another source also (if Ambleside also had issues, there must be another source as it isn’t affected by several of the above).

    1. East Clayton is underlain by silt and clay punctuated by two very large, deep sand deposits, one smack under the middle of the community. The soil is not impervious in these locations except where the marine clay is near the surface. It’s a safe bet that any infiltration structures must also be connected to the storm sewer system that performs as an overflow “safety valve” except where the large sand pocket is located.

      Vancouver and the vast majority of the Burrard peninsula is underlain by a thick, compacted layer of glacial till overlain predominantly with a relatively impervious and thin layer of marine silt and compacted sandy clay just below the organic surface horizon. Infiltration is slow to non-existent and easily backs up and overflows. I have seen too many raingardens, rock pits, buried concrete infiltration tanks and so forth fail over the years and be abandoned upon operations during even the first winter to arrive at any other conclusion than one does not eliminate a decent municipal storm sewer system over upland till without consequences.

      Source: Geoscape Vancouver.

      I have very limited available time to search for 10-year performance stats on East Clayton, but was able to find a document on Newton over a 5-year period (Newton has a very similar geology to East Clayton) which stated (paraphrasing here) that on-site and street drainage structures (drain / infiltration trenches and so forth) did not perform that well for intense or extended rain events, but did allow adequate infiltration for average or below average rainfall intensity, duration and volume. A recommendation was made to combine on-site and street-oriented storm water features with “community detention.” East Clayton has detention ponds, a common feature all over the flat lowlands of Surrey and Langley. They are harmonious with wetlands and large, year-round biofiltration ponds everywhere, but their primary function is detention, not infiltration.

      Source: Metro Vancouver, Surrey’s Storm Water History.

  6. Humans have been flushing human waste into water bodies for at least 5,000 years. In 1775 English inventor Alexander Cumming was granted the first patent for a flush toilet. The first modern flushable toilet was described in 1596 by Sir John Harington. In the late-19th century, a Londoner named Thomas Crapper manufactured and mass marketed his modern toilet with the ballcock mechanism still used to this very day.

    Implicit in the technology are two basic and enduring ideas: out of sight is out of mind and secondly, the solution to pollution is dilution. This is perhaps the rationale for Vancouver’s combined sewer system and the short sighted economic decisions taken back in the day.

    Today the sewer system of Vancouver receives an unimaginable array of toxic chemicals, some being radioactive, some hormonal, some algae producing nutrients from garburators, volumes of micro plastics from clothes washing machines, and so forth. If it can be flushed it probably has been flushed.

    Infrastructure plans indicate a major combined overflow outfall located in False Creek below the deck of Science World. There used to be a containment boom there woven through the pilings to catch flotsam offensive to the eyes. (out of sight out of mind)

    Fast forward to 2019 where we now have less than a decade going forward to move all of our activities to zero carbon emissions. We are out of time for upgrades over the next 30 years. We are out of time for conversions to grey water piping, rain water gardens and so forth. Blaming the entire mess on water foul is to say at the very least a very fowl argument.

    If you are an owner of a single family home in one of the combined system areas, you can take matters into your own hands so to speak. You can unplug your garburator, you can disconnect your crapper and install a composting toilet, you can drain your roof storm water into a stone pit in the yard, you can stop purchasing micro plastic laden products. You can do all of these things if you want, but why bother when all we need to do is agree to put up a sign that states, No Swimming!

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