Minutes from my community meeting on flooding

Dear neighbours,

Thank you for your patience.  We have been able to summarize the minutes from the meeting.  Each section will identify the staff who presented, and what was discussed.  At the bottom, you will see some of the questions asked, as well as the answers.  I would like to encourage you, if you have specific questions, to either forward to me to direct where appropriate, or save for when one of the city staff attends your home.  If you have reported a flood, you will be contacted by our staff offerings a follow up “CSI” investigation meeting.  Many of your specific questions will be able to be answered at that time.

Flooding Meeting

Monday July 20, 7:00 and 8:00pm

Westmount Public Library, London ON

Upon arrival residents were asked to include their contact information for follow up information and to be contacted by staff regarding concerns related to recent storm events.


 Virginia Ridley

City Councillor:

Welcomed residents and introduced city staff.
John Braam:

Introduced staff team in attendance and provided an overview of the information to be presented through a PowerPoint slide show.

Indicated June 23 flooding received similar rain intensity as Hurricane Hazel.

City wide the rain fell at a rate of 100mm/hour.

June 27 & 28 flooding was not as intense as June 23 rain fall.

June 27 & 28 was comparable to September 2014 rain fall.

John Lucas:

Displayed a ‘heat map’ – this map indicated where the most intense flooding occurred throughout the City of London as reported by residents.

Apologized that due to current lack of resources the data that has been collected has not yet been processed and analyzed as would typically happen.

Reviewed the normal City of London storm response plan.

Advised that, during the June 23 storm by the time the supervisor was at the first location, the storm was done and the rain stopped.  This presented issues with regard to completing an inspection of the root cause of the flooding occurrence.

During Jun 27 & 28 storm, a call centre was set up to receive citizen calls who were reporting property flooding conditions.

Some step a home owner should take when experiencing flooding include calling the COL to report.  Additionally a licenced plumber to evaluate the damage and possible solutions (per the Basement Flooding Grant Program). The City does not share information about flooded basements with insurance companies.

Environmental & Engineering Services uses the data received (calls) about flooding to help make recommendations regarding infrastructure, including areas identified in need of improvement. This info is reported to Council through Civic Works Committee.

Discussed the 10 year plan with respect to sanitary/storm water sewer improvements.  Approx. $400 million is allocated to improve the sewer systems.  The 10 year plan was submitted with the most recent budget approvals (2015).

Advised that the Operations Division assists with the functionality of the sewers.  Sanitary sewers are to be flushed at least once every 2 years This removes any build up that may be promoting flooding (grease build ups) and helps to identify problems such as broken or damaged sections of sewer pipe.

Scott Mathers:

Reviewed the sewer system as it currently is in place.

Reviewed that there are several reasons why homes may experience flooding;

Advised that homes built prior to 1985 have the weeping tile that surround the home (collecting rain water) connected to the sanitary sewer system underground.  The additional amount of rainwater entering the sanitary system puts additional pressure on the system – this results in water (sanitary) backing up in peoples floor drains, basement toilets etc.

Surface flooding also may have occurred – this could have been in the manner of water coming in through window wells, cracks in the foundation, etc.  Lot grading may assist with the correction of this type of flooding.

A large portion of Ward 10’s sanitary system drains to a central pumping station and then to the Greenway Wastewater Treatment Plant.

Briefly reviewed the Basement Flooding Grant Program and advised that homeowners could receive up to 75% funding, should they follow through with this program.

In the Westmount area there are two storm water ponds (Pincombe Ponds) – one collects the majority of the water run-off from the commercial plaza and the other collects the majority of the water run-off from the residential areas. A large portion of the Westmount area north of Southdale Road drains to the Pincombe drain.

The Pincombe drain has always been considered a flood plain area by the Conservation Authority and is susceptible to frequent flooding.

The way in which the storm and sanitary sewers flow or run was also reviewed.

John Lucas:

Advised that the data that has been collected has not yet been analyzed, due to the work stoppage (strike) as staff resources are not available to complete this large task.

Reviewed areas that the City of London can improve with communication to residents on how to maintain and prevent a flood free home.

This includes the removal of weeping tile and installation of a Backflow Valve and/or a Sump Pump.

Advised that a residential area of the city recently underwent a pilot project where the entire community was removed from weeping tile and a backflow valve installed.  The results of this pilot project were very positive – no flooding was found in these homes with the most recent storms.

An inspection of the PVC pipe may be of benefit as this pipe could be blocked with debris or even tree roots, which in turn could be assisting with the flooding.

Questions and comments that were brought forward


What do Pumping Stations do?

Pumping stations collect sewer water from a low point and pump it through a pressurized pipe to another location. Large portions of the Westmount area are collected at the Westmount pumping station and pumped to a sewer that drains the Greenway Pollution Control Plant.

Was Greenway over stressed during the recent flooding?

There was stress on the Greenway plant and overflows to the Thames River did occur during the storms.  The stress at the plant did not cause the basement floodings.

There was a lot of lightening and electrical activity – could it be possible that a pumping station was hit with lightening and shut off, subsequently stopping working?

City plants and pumping stations include backup generators that kick-in if a power outage occurs. Our investigation of the storm impacts are still underway but it this point it appears that the basement flooding experienced in Ward 10 was not related to the functioning of the City’s pumping stations.

As engineers, what do you see that is creating these flooding issues?

Basement flooding can be caused in a number of ways. The most common form of basement flooding in Ward 10 is described below:

Subdivisions approved prior to 1985 have their weeping tiles connected into the sanitary system. If you do not have a sump pump in your basement, your weeping tile are likely connected to the sanitary sewer.  During large storms rainwater from private properties enter the sanitary sewer system through these weeping tile connections. The large quantity of water in the sanitary sewers then cause backups to occur into the basements of homes through floor drains, showers, sinks and toilets.

If backflow valves are installed, what guarantee do we have that the flooding will stop – to expand, if 100 homes are within the neighbourhood and only 50 of them install the backflow valve, these are the residents that need a guarantee that flooding will not occur.

There are two objectives of the current basement flooding program: reduce the risk of flooding for the grant applicant and to protect the overall community by reducing the amount of rainwater in the sanitary system. The first objective is reached through the installation of a backflow preventer at the home of the applicant. The second objective is achieved by disconnecting the applicants weeping tiles from the sanitary sewer system.  Weeping tile disconnection from the sanitary sewer and backwater valve installation go hand in hand.  If weeping tile are not disconnected, a flooding risk still exists as sewer can back up into the weeping tile systems which could push water through your foundation; resulting in water seepage into your basement.

There are many different causes of basement flooding and although the installation of a backflow preventer will reduce the risk of a basement flooding there is not guarantee that the home will not be flooded in the future. Like any piece of safety equipment, backflow preventers must be inspected and maintained regularly to ensure that they function when you need them.

Is a certificate required from a plumber before the backflow valve is installed?

Plumbers need to get a building permit to install a backwater valve and have it inspected by a plumbing inspector.  This will ensure that it is installed properly according to Ontario Building Code.

If a home has a backflow valve and a sump pump, why is flooding still experienced?

Without more specific information, it is impossible to know.  With proper maintenance, sump pumps and backwater valves do work.  Every home in a post 1985 subdivision has a sump pump and there are hundreds of instances where backwater valves have functioned properly. If you have been flooded after installing a backflow preventers installed please contact the City (519-661-2500 x 5854)

We reported an issue during the Sept 2014 flooding, however no assessment was completed by staff then.  The strike was not in effect then – what happened to my assessment?

Most basement flooding issues can be addressed over the phone but staff are available to meet onsite if issue cannot be resolved on the phone.  To discuss your flooding issue, please contact the City at 519-661-2500 x5854.

On the heat map it showed a hot spot, which included my home.  When will this be addressed and when does the 10 year plan take effect?

The City’s capital budget is a 10-year plan for improvements to infrastructure city-wide.  Sewer replacement projects will not change your basement flooding risk.  The primary cause of basement flooding in Ward 10 was a result of the sanitary sewer becoming overloaded with too much storm water from the numerous weeping tile connections from each home.  In this circumstance, the age of the sewer is not the cause.   At this time, the only way to protect yourself from a future flooding event is to disconnect your weeping tile from the sanitary sewer and install a backwater valve.

If backflow valves are installed, will relief be felt community or city wide?

In order to protect yourself from flooding, weeping tile must be disconnected from the sanitary sewer in addition to the installation of a backflow valve.  This will protect your home from a future flooding event.  To achieve a community impact, many, many weeping tiles must be disconnected from the sanitary to remove a sufficient amount of water to prevent the sewer from backing up.  This grant program is a voluntary program and so it is intended as a one-off flooding protection measure for your home.

With respect to storm water ponds, what is the plan for the area south of Southdale Rd W – will we see ponds in this area as well?

There are currently drain improvements four additional stormwater ponds planned south of Southdale Road.  In most cases the basement floodings in Ward 10 were caused by backups in the sanitary sewer system and not the storm sewer system; therefore improvements to the storm system (building ponds and cleaning out the downstream channel) will not reduce the likelihood of future basement floodings.

My house was built after 1985 and has no weeping tile – how did my house flood?

Your house will have weeping tile.  If you do not have a sump pump in your basement, your weeping tile will be connected to the sanitary sewer.  Subdivisions approved before 1985 can have houses built after 1985 with weeping tile to sanitary so it is not uncommon to have a house built in the mid to late 80s with weeping tile to sanitary.

With respect to the grants that are available, will engineers take into consideration the lot grading and include some of the costs associated with the correction of lot grading into the funding that is available?

Lot grading changes are not currently part of the grant program for residential properties.  Please visit the City’s Basement Flooding Grant Program webpage for more information on the Grant Program.

I have contacted Risk Management to submit a claim.  They have refused the claim even after improvements have been completed on my home (for ex. Backflow valve installation) – why?

The City is responsible for ensuring that the sewer system is maintained on a regular basis. Basement flooding most often occurs due to the sewer system being overwhelmed by rainwater from the weeping tiles of private homes. Unless residents undertake work on their own homes, the risk of future basement flooding will continue. As the severity and frequency of inclement weather increases, municipal sewers will increasingly exceed the limits of earlier time designs.  Unfortunately there is no immediate remedy to the infrastructure short comings. The system is designed for capacity considered acceptable based on expected conditions at the time of construction.

The infrastructure in my area was replaced about 5 years ago, since then we have experienced flooding.  Prior to the infrastructure being replaced, we did not experience any flooding.

The primary cause of basement flooding in Ward 10 was a result of the sanitary sewer becoming overloaded with too much storm water from the numerous weeping tile connections from each home.  In this circumstance, the age of the sewer is not the cause.  So, the infrastructure replacement 5 years ago did not eliminate the weeping tile connections to the sanitary sewer, so your basement flooding risk is still present.

Regarding frequency of flooding, intense storms hit different areas in different years.  It is impossible to predict where or how often a storm will affect your home.  You could go years without being affected by a storm and then be affected twice in one week.  If you are at risk of basement flooding, please take advantage of the City’s grant program to protect yourself.

The City of London is continuing to build and put pressure on these out dated infrastructure systems.

When new development occurs within an area, it is paramount to the City that there is no impact to existing homeowners. As shown during the presentation the new commercial area along Wonderland discharges directly to the Westmount pumping station and does not contribute to the basement flooding that occurred throughout the Ward 10 area. The new residential area south of Southdale Road drains south and is pumped to an area that was not impacted by basement flooding.