ATTACHMENT A : Further Details & Evaluation of Pilot Downspout Disconnection Program

PREPARED BY: Karen Dennison, Manager, System Engineering, Waterworks

Lijing Xu, Sewer System Engineer, Waterworks

The Pilot Downspout Disconnection Program was approved by Council on April 29, 2008, started right after and completed in February 2010. This Appendix to the report to Council is in response to an action item in Council’s approval that Staff report back to Council with findings of the Pilot Program, including required resources and staffing to implement future phases of the program. A summary of the Pilot Program is provided in the Council report with a more detailed review and evaluation provided in this Attachment.

Disconnecting downspouts from the sanitary sewer system was selected as the first step of I/I reduction effort in the Thornhill pilot study area. According to the current design standards, roof runoff should be discharged onto soft surfaces (i.e., lawn or back year garden areas) and through an overland flow path into the storm system. However, construction and design practices for municipal and private sanitary systems have evolved over the past fifty years. In some older areas of the Town (i.e., developed before 1980s), developments did not have major/minor drainage systems in place. As well, owners/builders have occasionally directly connected roof downspouts incorrectly into the sanitary system. When these incorrect connections exist, the local sanitary sewers can be easily overwhelmed, surcharging and backing up into residents’ basements during intense wet weather events and imposing social/environmental hazards to the local community. Downspout connections to the sanitary sewer system are strictly prohibited under the existing Markham Sewer By-Law #436-86 and the Regional Municipality of York Sewage and Land Drainage By-Law # S-0064-5002-009.

The pilot area is located at the north-east corner of Yonge Street and Steeles Avenue in Thornhill and is referred to the Grandview Area with a total of 766 homes. This area was selected for the pilot study based on historical basement flooding records and previous flow monitoring results showing that the local sanitary system experienced relatively high inflows during wet weather events; this is usually an indicator of the presence of cross connections such as downspout connected to the sanitary system.

A Working Group was created for the Pilot Program, consisting of Councilors and staff. The Working Group developed and oversaw a comprehensive approach to conduct the Pilot Program. The Town’s approach compared favorably to Best Practices employed in other municipalities across Canada. Valuable hands-on experience was gained through the implementation of the Pilot Program. A review of each component of the Pilot Program was conducted and Best Practices were determined for any future program implementation.

The pilot program was conducted with the following four major components:

1. Public communication and education

2. Site investigation

3. Downspout disconnection implementation

4. Evaluation of program effectiveness

5. Development of Best Practices

1. Public Communication and Education

An effective communication and education program was developed and delivered. The following public outreach activities were conducted:

1) A 1^st newsletter, containing general pilot program information was delivered to all 766 homes in the study area in early June 2008 at the program start.

2) The 1^st public meeting for all residents in the pilot area was held on June 19, 2008.

3) The 2^nd newsletter providing investigation results and technical/financial assistance information from the Town was delivered in November 2008.

4) The 2^nd public meeting was held on March 25, 2009 for those 45 homes identified with downspouts directly connected to the sanitary system.

5) An information portal was created on the Town’s website. The two newsletters were posted for the entire project period.

6) Various letters were sent to individual residents to address specific issue.

7) A full time Project Coordinator worked closely with the residents to address their specific questions and concerns.

The public communication/education program was the key component of the downspout disconnection project. It provided opportunities for the residents to understand and support the program and at the same time allowed Town staff to address any program issues in a timely manner and carry on the project in an efficient way. Activities carried out in the Pilot Program were effective and sufficient and similar activities should be continued in the extended program implementation.

2. Site Investigation

Waterworks staff conducted a multi-stage approach to conclusively identify any roof downspouts directly connected to the sanitary system. The following investigative steps were undertaken in the sequence as listed below:

1) Preliminary Property Survey

A lot survey of each property (766 homes) was conducted to locate downspouts and note their connection status, i.e., disconnected above ground or connected below ground. 256 homes were found to have their downspouts previously disconnected and flowing onto the ground surface. This step reduced the house number to be investigated in next steps.

2) Smoke testing of Sanitary Sewers

Smoke testing is a cost effective measure to locate cross connections in the sanitary system including downspout connections. A total of 27 homes were identified as having potential incorrect connections to the sanitary system.

3) Smoke testing of Storm Sewers

The storm sewer system was also smoke tested to help identify if remaining homes with downspouts connecting below ground went to the storm system, not the sanitary system. A total of 178 homes were confirmed to be connected to the storm system. 332 homes still required further investigation to definitely conclude the downspout connection status. A review of the plumbing cards of the area indicated that there were p-traps installed in some storm laterals which make it impossible to identify whether downspouts were connected to the sanitary or storm system by smoke testing as smoke can not penetrate through sitting water in the p-trap.

4) Dye Testing

Dye testing with clear water and CCTV cameras located at the service connection in the sewer was undertaken for the remaining 332 in-conclusive homes. Further, those homes where smoke testing (sanitary and storm system) results conflicted, were dye tested.

Following completion of these incremental investigation activities, a total of 45 homes (83 downspouts) were conclusively found connected to the sanitary system. Downspout connection status in the pilot area is summarized in the table below. These pilot area statistics were used to estimate costs for the future program.

Site Investigation Summary

Activities	Findings	Quantity	Overall(%)
Lot Survey	Total number of homes	766	100%
	Homes with downspout disconnected (before the program)	256	33%
	Homes with downspout connected below ground	510	67%
Smoke Testing	Downspout connected to storm sewers confirmed by smoke testing	178	23%
	Downspout connected to sanitary sewers confirmed by smoke testing	10^1
	Inconclusively connected homes after smoke testing	322^2
Dye Testing	Homes dye tested (includes ^1& ^2 above)	332	43%
	Homes with downspout connected to storm sewers confirmed by dye testing	253	33%
	Homes with downspout connected to sanitary sewers confirmed by dye testing	35
Others	Inconclusively connected homes	34	4%
Summary	Homes Conclusively Identified with D/S Connected to Sanitary Sewer	45	6%^2

Following extensive site investigation efforts, there were still 34 homes with inconclusive downspouts connection status (i.e., their downspouts connected below ground but we can not confirm the connection to either the sanitary or storm sewer by smoke testing or dye testing). Inconclusive results occurred for a variety of reasons such as plugged downspouts and laterals, unreachable downspouts on 2 story homes, or connection to underground infiltration systems.

A peer review of the Town’s site investigation approach was conducted by AECOM Canada Ltd. it was concluded that the site investigation methodology generally complies with and in some areas, exceeds the standard industry best practices. Two recommendations were provided from the peer review for further consideration in any future program implementation.

1) The use of colour dye(s) instead of clear water in dye testing

2) Conduct building inspections and foundation drain tests to identify other sources of cross connections in addition to roof downspout connections.

This multi-stage investigation approach for the Pilot Program was proven to be cost-effective to conclusively identify downspouts connected to the sanitary system. Each step substantially reduced the scope for next step and confirmed results from previous step. The following four steps conducted for the Pilot Program are recommended to be continued in the extended program implementation.

1) Preliminary lot surveys of the properties to map all downspout locations and connection status (i.e., connected or disconnected)

2) Smoke testing of sanitary sewers.

3) Smoke testing of storm sewers.

4) Dye test of those downspouts with an inclusive connection status.

Site investigation activities in the pilot program were conducted by Waterworks staff, thereby gaining first-hand experience for future program guidance. For the proposed extended program, these activities will be contracted out and managed by Waterworks staff.

3. Downspout Disconnection Implementation

Four components were included in this stage:

1) Technical Assistance to Home Owners

- A clear explanation of the By-law requirements was given to 45 home owners who need to disconnect their downspout from the sanitary sewer.

- Detailed information was provided to home owners presenting the disconnection job to be done by either themselves or hired contractor.

- Multiple site visits as necessary were made to each affected property for inspection and verification of the disconnection

2) Financial Assistance to Home Owners

A Financial Assistance Package was developed by the Working Group to assist home owners to complete the disconnection work:

- 80% of the cost for completing the downspout disconnection, to a maximum of $500.

- 100% of the cost up to $150 for a rain barrel purchased by the home owner

Payment to home owners was made after the required application form was completed, original invoices were submitted and after on-site verification of the disconnection was made by Town staff. Financial assistance was made available for a twelve month period starting from the time that the property owners were first advised of their incorrectly connected downspouts. After the expiry of twelve month period, affected property owners would no longer be eligible for financial assistance from the Town. In the pilot area, all 45 home owners completed the disconnection with the 12 month period.

Due to different site conditions, costs for these 45 homes to complete their disconnection work varied from the maximum of $2596.39 to the minimum of nil (the cost was minimal and the residents did not apply for the subsidy). A total of six homes (13%) purchased a rain barrel. 33 homes (73%) spent less than $500 to complete the disconnection work. On average, the total cost for each of 45 home owners was $390 and Town subsidized $218 of this, totaling $9,800 for all 45 homes. Ten homes maximized the Town’s financial assistance amount of $500. Graphs below show the distributions of total costs and Town’s costs to complete the disconnection work for those 45 homes.

The downspout disconnection programs have been implemented across the country in four different ways. One method is that the municipality removes the connection at its cost with the home owner’s consent. The second method is to encourage property owners to voluntarily disconnect at their own cost through an education program. The third method is to strictly enforce mandatory downspout disconnection By-laws. The fourth method is to provide financial assistance to offset some home owner’s cost. For the Pilot Program, the Town chose applying a financial assistance package.

Markham chose to provide financial assistance for residents in the pilot program. The intent was to facilitate rapid compliance with the By-law and the proved to be effective. Within four months (April to July 2009), the majority of home owners (42 out of 45) completed the disconnection work. By the end of January 2010, all 45 homes had their disconnection work completed.

Staff recommends implementing this financial assistance package into any future downspout disconnection program for following reasons:

· This program was generous and the actual cost to the Town was moderate, i.e. $218/home (totaling $9,800 for 45 homes).

· It sped up the compliance process and reduced staff Sewer Use By-law enforcement effort. If disconnection was accomplished through enforcement, costs are estimated at $50 K for the 45 homes (involving the Clerk Department, By-Law Department, and Waterworks).

· It provided consistency Town-wide, especially in the Greater Thornhill area, where most of the residents are aware of the Town’s financial assistance program for the pilot area

3) Progressive Enforcement of the By-Law

The By-law enforcement procedure was planned to initiate after a 12 month period starting from when the home owners were first advised of their incorrectly connected downspouts. It was not necessary to apply this procedure in the Pilot Program since 100% of the residents complied within the 12 month period of time given for disconnection.

4) Post Program Site Inspection

A site inspection will be conducted in the summer of 2010, a year after the disconnection was completed, to assure that all disconnections (45 homes) remain in effect. We also recommend that this practice be continued annually for next five years to assure that the disconnection remains in effect permanently.

The Pilot Program was a successful model, achieving 100% disconnection compliance within the planned enforcement period (12 months). This success was in part due to the Town’s financial assistance program, a full-time project coordinator who liaised closely with residents, and local residents’ receptiveness to the program having been recently flooded in 2005.

4. Evaluation of the Pilot Program Effectiveness

A continuing flow monitoring program was put in place in the pilot area in September 2008 to monitor system flow conditions under pre- and post-downspout disconnection periods. The disconnection started in April 2009 and the majority homes (42 out of 45) completed their disconnection by the end of July 2009. A total of 19 events were captured before the disconnection program and a total of 8 post-condition events have been analyzed and included in this report. The statistical analysis results indicated that there are substantial I/I peak reductions as the result of disconnecting downspouts. The table below summarizes the number of downspouts disconnected and the estimated I/I peak reductions in each flow monitoring catchment.

Flow Monitoring Location	Disconnected Homes	I/I Rate Reduction Estimation
T1	39	43%
T2	17	55%
T3	3	49%
T4	1	38%

Note: There are two disconnected homes located outside of the flow monitoring catchments.

Catchment T1 includes the upstream catchment T2 and covers the majority of disconnected homes (39 out of the total 45). The estimated I/I peak reduction rates from T1 can be used to represent the I/I reduction effectiveness of the Pilot Program, which is about 40%- 50%. This is a significant reduction on I/I peaks.

Figures below present rainfall events and associated sewer flows during a pre-downspout disconnection event (September 30, 2008) and a post-downspout disconnection event (August 20, 2009). The effectiveness of the downspout disconnection program on I/I reduction is well demonstrated by these two example events. The rainfall intensity of the pre-program event was almost three times of the post-program event intensity but these two events generated almost same peak flow rates in the sewer system.

5. Best Practices Package Developed from the Pilot Program

The Pilot Program was a successful model. A lot of Best Practices proven by the industry were already adopted in the program at development stage and many hands-on experiences were gained during the program implementation. A comprehensive, cost-effective program implementation package was developed according to the experience learned from the Pilot Program and summarized below:

1). Public Communication and Education

i. Newsletters

ii. Public meetings

iii. Information Center on the Town website

iv. A designated project coordinator to address residents concerns and questions

2). Site investigation to conclusively identify any downspouts connected to the sanitary system

i. Lot inspection

ii. Smoke testing on the sanitary system

iii. Smoke testing on the storm system

iv. Dye testing

3). Downspout disconnection implementation

i. Technical assistance

ii. Financial assistance

iii. Enforcement by By-Law

4). Program effectiveness evaluation

Flow monitoring projects should be in place for pre- and post-disconnection periods at some key locations in the system to verify the effectiveness of the program and at the same time provide valuable information of system performance.