Urban Water and Your Property Part Two: Drainage

Last week we shared a blog post written by former manager of Toronto Water and current EAC volunteer, Mike Price, on urban water and your property that focused on incoming water. Part two of the post, also contributed by Mike, examines considerations for urban homeowners around water that leaves your property, also known as drainage. 

Photo: bit.ly/NeUL72

The water leaving a typical urban property leaves via surface flow or underground pipes. The surface flow during a rainfall event will take with it all surface pollutants used on, or deposited on, the surface. The underground pipes can be: 

    -  Sanitary sewer containing sanitary waste and maybe weeping tile water depending on the municipality

   -  Storm sewer containing rain water and maybe weeping tile wate

   -  Combined sewer where all liquids are put into one pipe

Current Issues regarding municipal waste water treatment

·    -  Surface waters, lakes, rivers and oceans, are becoming contaminated from human activities, resulting in polluted recreational waters, damage to fish and shellfish, and changes in the whole ecosystem. 

·     - Storm sewer flows are not treated but empty into the nearest waterway

·     - Sanitary sewage takes huge amounts of power to pump and treat before release into the environment

·     - Combined sewers are prone to surcharging and overflow during heavy rainstorms causing surface water pollution

·      - Sanitary sewers and especially combined sewers are prone to backing up and causing basement flooding in heavy rainstorms

·      -  Previous drainage design criteria often required roof drains and weeping tiles be connected to the sewers (thus adding clean water to be expensively treated at sewage treatment plants)

Current solutions for Urban drainage dischargers

    
     To assist with the big picture - sanitary waste solution:

 -   Reduce flows to municipal sanitary sewer by installing water efficient fixtures

 -   Reduce flows to municipal sewers by disconnecting roof downspouts from the sewer

-    Reduce flows to municipal sewers by installing sump pump for weeping tile water and discharge the clean water to the ground for irrigation

 -   Consider ‘grey-water’ reuse such as flushing toilets

 -   Consider a sewer backflow preventer to mitigate against basement flooding

    To assist in implementing storm water management techniques:

 - Rainwater harvesting (methods listed earlier)
 - Eco-gardening

             - Minimize need for water

             - Reduce lawn area  

             - Move to drought tolerant lawn grass

             - Leave grass clippings on the lawn

             - Use ‘push’ lawnmower to reduce pollution

             - Eliminate pesticides and fertilizers on lawns

             - Use shade trees

             - Xeriscaping garden designs

             - Mulch gardens to retain water

             - Discharge roof water via ‘chains’ to garden

             - Consider natural ponds to capture rainwater

             - Decrease paved areas, increase porous areas

   - Don’t wash the car in the driveway

  - Don’t dump any soapy water, waste oil or chemicals down the storm drain (it goes straight  to the nearest creek!)

- Pick up animal feces 

Urban Water and your Property

The following blog post was written by Mike Price, former general manager of Toronto Water and highly valued Ecology Action Centre volunteer. This  post provides a comprehensive overview on the issues and solutions related to incoming water on a property. A subsequent post will look at outgoing water, or drainage. Thanks for the great blog contribution, Mike! 

Downspout deco-chain (Photo: M. Price)

The water used on a typical urban lot comes from two directions. Down from the sky or out of a water pipe. Rainfall can be good, and sometimes hazardous, but we don’t make the best use of it. The water from your tap (potable) can be from several sources:

        - Private untreated supply from a well on the property

        - Municipal treated supply, from the tap, originates from surface water (lake or river) or ground water from wells

·        Current Issues regarding municipal water supplies

      -  Surface waters, lakes and rivers, can become contaminated from human activities. 

      -  The volume of supply from surface water in Canada is dwindling due in part to ‘climate change’, but also due to increased demand. 

      -  Ground water supplies are similarly impacted but depending on the depth of the well the ability to replenish is being negatively impacted by human intervention.

      -   A large amount of energy is used to treat and pump the municipal water to reservoirs and around the water distribution system. 

      -  During hot summer months up to 50% of the water supplied is used for external ground watering.

       - Throughout the year about 60% of the building water use is for flushing toilets

Recreational beach closure (Photo: M.Price)

. Current solutions for urban water providers and users

    Water providers (Province, Municipalities and/or water utilities)

  -   Prepare and implement Source Water Protection Plans

  -   Prepare and promote Water Efficiency Plans

  -   Actively seek out and repair water pipe leaks

  -   Eliminate unnecessary fire hydrant flushing

  -   Minimize energy used in the treatment and distribution of potable water

  -   Prepare and regulate Pollution Prevention Plans

  -   Prepare and implement Storm Water Management Plans

   -  Mitigate the impacts of Combined Sewer Overflows

   Water users (residential and ICI property owners)

 -  Minimize tap water use

     a)   Low flush toilets

     b)   Reduced volume shower and tap heads

     c)   Grey water re-use (for toilet flushing)

    d)   Use more drought resistant garden plants (called Xeriscaping)

    e)   Eco-gardening

     f)   Use timers on automatic sprinklers

 - Maximize rain water use

     a)   Rainwater harvesting

               1.   Downspout disconnection

               2.   Grade property to keep rainwater from running off the property

               3.   Use rain barrels for garden watering

               4.   Create specific areas for a rain garden

               5.   Minimize paved areas

Rain barrel installed at disconnected downspout  (Photo: M. Price)

Pain in the Drain

 This article was written by Heather Hunter and published in the Summer 2012 edition of 'Between the Issues', the Ecology Action Centre's quarterly publication. Thanks for covering this important topic, Heather. The full BTI can be downloaded here.

The last time you were caught in a downpour, jumping over sidewalk rivulets and trying not to get splashed by passing cars, perhaps your thoughts didn’t automatically jump to where does all this water go? What contaminants might be in it?  But stormwater, the rainwater and melted snow that runs off roads, lawns, roofs and other hard surfaces, is an area where some real environmental action is needed. Storm water often contains motor oil, gasoline, sediment, fertilizer and other contaminants which damage natural aquatic habitats.  Without proper stormwater management practices, serious environmental and economic consequences can occur such as erosion and loss of habitat.

Cameron Deacoff, an Environmental Performance Officer with the Halifax Regional Municipality, took some time to explain why we should be giving this issue some major consideration and steps that we can take at individual and municipal levels to improve our storm water management practices.

Why you should care about storm water management
On earth there is a finite amount of water.  Fortunately, water is efficiently conserved through the hydrological cycle – including the processes of evaporation, transpiration, condensation, precipitation, surface runoff & percolation. This natural water cycle is disrupted by human intervention.  In urban landscapes in particular, impervious surfaces such as roofs, roads and parking lots render the land unable to absorb water. Instead, stormwater runs over streets and sidewalks and along the way becomes polluted with oil, garbage, fertilizers, pesticides and other contaminants.  In fact, studies have shown that storm water conveys up to 600 pollutants, many of which may be harmful to both humans and the environment.  Unlike sewage wastewater, stormwater is often not treated before it enters our waterways.

While good stormwater management has always been important, it is now being seen as more of a “hot button” issue as people are gaining a better understanding of the impact on environments, including erosion, removal or destruction of fish and wildlife habitat, and pollution causing direct damage to fish and other aquatic organisms.  We are understanding that stormwater needs to be managed - efforts should be made to reduce contaminants in street run-off, and there should be some treatment before stormwater joins up with natural waterways.  In addition, there is an understanding that we should avoid directing stormwater into wastewater systems (i.e. sewers that handle wastewater from toilets, tubs, laundry etc) because wastewater systems are not designed to treat stormwater flows. During heavy rainfall events, treatment processes can fail as throughput exceeds the capacity of treatment facilities, resulting in untreated overflows. Other risks associated with poor stormwater management include flooding, basement backups, and associated property and financial losses.

The importance of stormwater management is not going to decline any time soon.  Cameron explains that aging infrastructure is making the issue more serious today. “Much of the infrastructure in the ground was put there several decades ago,” he says, “and maintenance and replacement needs are ramping up”. He adds that “climate change is also having an impact on the issue, because our weather patterns are changing, resulting in increasing volumes of precipitation, and increasing intensity of rainfall events. Winters have been milder, resulting in less storage of precipitation as snow and ice, making for shifting hydrological patterns for which stormwater management systems were neither designed nor constructed.”

What you can do
To enhance your individual stormwater management practices, Cameron provided the following tips:

• Retain as much natural land cover on your property as possible (i.e., do not cover the ground with asphalt, concrete, etc. unless necessary).
• Disconnect your downspouts (eaves troughs, foundation drains, sump pumps, etc.) from your house onto the surface of your property for drainage into the ground; or at least ensure that they are not connected to the wastewater sewer system.
• Store and manage waste materials properly so that they do not flow into storm sewers, swales, etc., during a storm. This includes covering dirt piles, removing litter and pet waste.
• Landscape your property with plants and other materials that are native to where you live. These have fewer needs for fertilizers and pesticides, which should be used sparingly if at all.
• Support fees for storm water management. These services benefit you and the environment.

At a municipal policy level, there are many steps that cities and towns in NS can be taking to improve stormwater management practices.  Some recommendations include:

• Having your town or city conduct a review of water-related issues within their jurisdictions, and those shared with neighbouring municipalities.
• Ensuring that municipal urban design & planning jointly consider water quality and water quantity along with land use and transportation.
• Devote some attention to retrofitting issues in older urban areas, not all towards improving development practices in new "greenfield" areas.

Some municipalities such as the City of Cambridge in Massachusetts and Victoria BC have begun implementing progressive by-laws to counter stormwater pollution.  In Cambridge, significant investments in catch basin cleaning, street sweeping, and urban forestry programs have been made.   

In Victoria, bylaws have been passed for businesses as well as construction and development sites. Businesses must be fitted with a “Storm Water Rehabilitation Unit”, which is a generic term for any system designed to remove targeted contaminants. In general, any system that removes solids such as gravel, sand and silt, and floating materials like oils and trash should be adequate. At construction sites, regulations prevent construction waste water from being directly joined to drainage systems or sewer systems, hazardous wastes are tightly controlled with spill plans in place, and after construction has finished the site must be cleaned up to prevent excess gravel, dirt and pollutants from entering natural waterways.

Stormwater management practices may vary across municipalities, and depending on existing infrastructure, different levels of investment may be required. However, the first step is to raise our level of awareness about this issue.   To reduce harm to our natural waterways, and our overall ecological footprint, stormwater management must become a permanent part of our “environmental consciousness”.

Lawn care and stormwater pollution

Photo: www.inharmony.com

Pesticides and fertilizers are among the many common pollutants found in stormwater runoff that can impact water quality. When pesticides wash into local waters they contaminate the water and poison aquatic life. Fertilizers contain nutrients such as phosphorus and nitrogen. These nutrients can overload natural water bodies and result in the growth of algal blooms which use up the water's oxygen and impact fish and other aquatic organisms. 

To protect water quality of lakes, rivers and streams it is strongly recommended that property owners reduce or eliminate the use of cosmetic pesticides and fertilizers. You can still have a healthy, happy lawn without the use of chemicals. Here are some tips to protect your lawn and the surrounding environment:

•  Vinegar is one of the most easily accessible and safest ways to kill weeds. The acetic acid in vinegar breaks down plant cells and kills the top growth.  But, because it does not kill the roots, you’ll have to reapply.   

• Corn gluten meal, found at lawn and garden centres, acts as both a fertilizer and an all-natural herbicide that is effective at preventing the growth of dandelions and other weeds.  It can be applied to an established lawn in early spring before the weeds germinate.

• Kitchen compost and lawn waste make excellent natural fertilizer for your lawn. Or better yet, brew your own compost tea!

• Mow high (6-7 cm) and leave grass clippings on the lawn, which adds nutrients to the soil. The shade of tall, dense grass will overcrowd weeds and reduce growth.

• Aeration is the best fertilizer. Use an aerator to pull plugs of grass out of your lawn to allow more air to reach the roots. This promotes a healthy lawn and results in vigorous new growth.

•  Landscape with native species that will have less need for fertilizers and pesticides.

• Also, remember to pick up after your pets. Pet waste carries numerous bacteria which finds its way into the storm sewer system and ultimately into streams, rivers and lakes.
  

Thermal pollution

When we think of how stormwater impacts lakes, rivers and streams, we tend to think of sediment and other contaminants that degrade water quality. We rarely think of how elevated runoff temperatures, known as thermal pollution, can greatly alter the temperature regime of natural water bodies. On hot days, impervious surfaces, such as parking lots and roofs, absorb and emit heat.  When it rains, heated runoff that flows over these surfaces can potentially increase the temperature of receiving waters. Increased temperatures can negatively impact coldwater fish populations by interfering with spawning and migration patterns, decreasing dissolved oxygen levels and even resulting in fish kills.

Stormwater Best Management Practices have an effect on runoff temperature, and the University of New Hampshire's Stormwater Centre has been researching the effectiveness of various BMPs in regulating thermal pollution from stormwater runoff.

They found that surface systems, such as retention ponds, that are exposed to direct sunlight provide little no reduction of high runoff temperatures and can potentially increase already elevated summer runoff temperatures. Various infiltration and filtration systems were best able to moderate runoff temperatures by thermal exchange with cooler subsurface materials. Systems with a large subsurface area had the greatest ability to buffer runoff temperatures. The full report titled 'Examination of Thermal Impacts from Stormwater Best Management Practices' can be found here. 

Brook Trout. (Photo: Source)

Pioneer Park Stormwater Management Project

The Town of Richmond Hill, Ontario, created a stormwater management park to collect and treat runoff as well as provide flood and erosion protection to neighbouring communities. Originally built in the 1980's, Pioneer Park treated runoff from 26 ha of residential development. Redesigned in 2009/2010, the improved stormwater management park now provides water quality and quantity services to a 740 ha catchment area.

The park consists of a wet pond to treat runoff from everyday rain events, a dry pond to collect and treat runoff from major, intense rainfall events, an oil grit separator for pre-treatment and a channel for fish passage. This project was a 2010 winner of Insurance Bureau of Canada's Watershed Awards.

The completed stormwater management park. Photo: www.rmconstruction.ca

Under construction in 2010. Photo: www.rmconstruction.ca

Check out this great video to learn more about how Pioneer Park was created and the many environmental and economic benefits it provides to the Town of Richmond Hill. This video was provided by Insurance Bureau of Canada.

Backwater valves

Basement flooding can be caused by a number of reasons including cracks or leaks in basement walls, blocked pipes, failure of foundation drains (weeping tiles) and poor lot drainage. Heavy rain events can also overload city sewer systems and lead to sewage backing up through house sewer lines and flowing into unprotected basements. Damage from sewer backups is costly for homeowners and municipalities. The Canadian insurance industry pays an estimated $1.7 billion each year in claims due to water damage. 

A backwater valve is a flood-proofing device that prevents sewage in an overloaded public sewer system from backing up into your basement. This fixture, placed on a sewer line in your basement, works as a one way system - sewage can go out, but not back in. The backwater valve automatically closes if sewage backs up from the main sewer line. You should contact a licensed plumber to install a mainline backwater valve and to obtain the proper plumbing permits.

Backwater valve (source: plumber-master.com)

 

Since decades ago, the National Plumbing Code has required the installation of a backwater valve. In HRM, construction or renovation projects have been required to follow the National Plumbing Code including the installation of backwater valves. This became more closely monitored after HRM amalgamation in 1996, when all of HRM required inspections with the issuance of a permit for construction or renovation projects.

Today you are required to get a construction permit (and inspection) for any renovation or construction exceeding $5,000 or when performing structural work. This would include adding or altering a connection to the storm or ssystem such as installing a backwater valve (the only exemption is when replaceing a plumbing fixture).

For more tips on reducing the risk of basement flooding, check out this brochure and video provided by the Insurance Bureau of Canada.