June 30, 1999
To:Works Committee
From:Commissioner, Works and Emergency Services
Subject:Gerrard Street Water Main
Alternatives to Increase Supply Pressure (Ward 26 - East Toronto)
Purpose:
This report provides results of a review of alternatives to increase the water supply pressure in the trunk water main
servicing the area bounded by Main Street, Gerrard Street, Victoria Park Avenue and Kingston Road.
Funding Sources, Financial Implications and Impact Statement:
There are no financial implications as a result of this report.
Recommendation:
It is recommended that this report be received for information.
Council Reference/Background/History:
The Works and Utilities Committee on May 19, 1999 had before it a report (dated May 7, 1999, Item No. 10) from the
Commissioner of Works and Emergency Services providing information in response to concerns raised by a number of
residents in the Main and Gerrard Street area about the adequacy of their water supply. This report noted that supply
pressures would drop in a household when a tap was turned indicating a reduction in flow capacity due to the condition of
local water mains, substandard sizing of service connections and substandard internal house plumbing. The report also
noted that the supplied static pressure is at the lower end of operating standards because the area is located in the upper part
of Pressure District No. 2 at a relatively high elevation. Four main options to solve the problem were noted including:
(1)Increase the static pressure in the Gerrard Street trunk main;
(2)improve water services to properties;
(3)clean and line water mains; and
(4)enlarge existing connections and construct new connections to the trunk water mains.
Work on Options 2 and 3 which involve improving the water services to properties and the cleaning and lining of local
distribution water mains are currently underway.
As these measures may not fully address the situation, a motion was adopted at the committee meeting recommending that
staff conduct a review of the alternatives outlined in Option 1 to increase the lower range of the supply pressures in the
Gerrard Street trunk main; such review to determine the feasibility of the alternatives and the estimated capital and
operating costs associated with them; and that the Commissioner of Works & Emergency Services be requested to report
on the results of the review at the July 14, 1999 Works Committee meeting.
Comments and/or Discussion and/or Justification:
The source of water supply to this area is a 1200 millimetre (mm) trunk water main running from the R.C. Harris Filtration
Plant to St. Clair Reservoir. This trunk main supplies the Main and Gerrard area through two branch connections, one at
Wayland Avenue and Gerrard Street, the other at Kingston Road and Kingswood Road. The citywide standard is that
pressure at branch connections should fall between 276 kiloPascals (kPa) (40 pounds per square inch (psi)) and 793 kPa
(115 psi) at all times. Pressure measurements at these branch connections taken between May 26 and June 2, 1999 indicate
that supply pressure was between 280 (kPa) (41 psi) and 450 kPa (65 psi). The lower pressures occur when only one pump
is operating to supply this main at the R.C. Harris, while the higher pressures occur when two pumps are operating.
Pressures at these branches are at the lower end of the standard because this area is in an elevated section of Pressure
District 2.
The report identified three alternatives under Option 1: changing the pumping operations at R.C. Harris Filtration Plant; the
installation of a booster pump; and a change in the boundaries between Pressure Districts 2 and 3. A description of these
alternatives and results of a preliminary analysis are as follows:
(1)Changing the Pumping Operations at R.C. Harris Filtration Plant
Currently only one pump is required to be in operation to supply the Gerrard Street main except during the high demand
season from May to September and from 11:00 p.m. to 7:00 a.m. daily. Operation of two pumps for the rest of the year
would require the throttling of R.C. Harris pump discharge valves and would significantly constrain operational flexibility.
Moveover, operation of two pumps would not be possible during periods of extremely low demand or during plant
shutdowns for maintenance purposes.
Increasing supply from the R.C. Harris plant to the transmission system by operating two pumps into the Gerrard Street
main must be offset by decreasing supply from the F.J. Horgan and R.L. Clark plants. This has significant energy cost
implications. Given that hydro consumption charges in the amalgamated city have not been harmonized to date, hydro
consumption is more expensive at the R.C. Harris than at other plants. It is estimated that operating two pumps at R.C.
Harris when possible will result in an annual hydro cost increase of $56,000.00. In addition, peak hydro consumption
charges resulting from running two pumps throughout the day instead of only from 11:00 p.m. to 7:00 a.m. are estimated to
be $57,000.00 annually, for a total annual increase in energy costs of $113,000.00. As indicated in Appendix "A"
(attached), 20-year life cycle costs would be $1.85 million.
This alternative is not considered feasible to implement.
(2)Construct a Booster Pumping Station
A booster pumping station possibly located in an underground vault at Wayland Avenue and Gerrard Street would be
capable of boosting supply pressure to this area by approximately 200 kPa (30 psi). Based on this preliminary assessment,
construction costs for this station would be approximately $350,000. Assuming average day consumption of 2,000 cubic
metres per day, annual operating and maintenance costs for this station would be approximately $7,000.00. Twenty year
life cycle costs are estimated at $465,000.00.
The City of Toronto has recently discontinued operation of a similar underground pumping station at Dorset Avenue and
Kingston Road in Scarborough. Operation of this station proved to be problematic as difficulty was encountered balancing
supply pressure through periods of high and low demand.
Accordingly, this alternative should not be pursued.
(3)Adjust the Boundary between Pressure Districts 2 and 3E
If pressure district boundaries are adjusted so that the Main and Gerrard district is included in Pressure District 3E instead
of District 2, water would be provided at higher pressure to the area in question. This would result in pressures in the area
of between 520-585 kPa (75-85 psi). Preliminary hydraulic analysis has shown that this would have a minor impact on
overall District 3E pressures. More detailed hydraulic modelling would need to be completed to confirm that the low
pressure problem is not shifted from one area to another.
Incorporating this system modification would require the construction of a small section of water main as well as the
installation of a metering chamber and a check valve to allow for a secondary supply to the area. The estimated cost of
construction is $235,000.00, with an increase in annual operating and maintenance costs of $12,500.00. This alternative
has the lowest life cycle cost at $440,000.00.
Based on a preliminary analysis this alternative appears feasible, however, further analysis is required to confirm costs and
hydraulic impact.
Workplan:
Work to improve flow capacities and pressures is currently underway, including repairs and upgrades to property water
services and the cleaning and lining of local mains. Completion of the water service repair contract is expected in July
1999, with the water main cleaning and lining contract targeted for completion in November 1999. After completion of this
work, a representative survey of supply pressures and flows will be undertaken to assess the effectiveness of the upgrades.
This should be completed by the end of 1999.
If pressures are still considered unsatisfactory, an analysis must be made to determine if further local upgrades, including
enlargement of and/or added connections between the trunk main and sub-trunk mains, or an increase in bulk supply
pressure, are required. This analysis would consist of the taking of pressures at various representative locations throughout
the affected area during maximum and minimum hour demand periods to determine the extent and location of local
pressure loss. This analysis can be completed by the spring of 2000.
Funding will be requested in the 2000 Capital Works Program to enable timely implementation of projects required for
further service upgrades, including bulk supply pressure increase. If it is determined that an increase in bulk supply
pressure is the most effective remedy to improve service in this area, the pressure district boundary change will proceed
pending results of the detailed analysis of the alternative.
Conclusion:
A preliminary review of alternatives to increase the water supply pressure in the trunk water main serving the area bounded
by Main Street, Gerrard Street, Victoria Park Avenue and Kingston Road has been undertaken. The alternative involving
pressure district boundary change appears feasible but requires more detailed assessment. Funding will be allocated in the
2000 Capital Works Program for implementation of further service upgrades in the event pressure improvements are not
realized following local upgrades currently underway.
Contact Name and Telephone Number:
Hiroshi Taniguchi
Director, Water Supply
Phone: (416) 392-8220
Fax: (416) 392-3639
E-mail: htaniguchi@metrodesk.metrotor.on.ca
Michael Price P. Eng., FICEBarry H. Gutteridge
General ManagerCommissioner
Water and Wastewater ServicesWorks and Emergency Services
GM/HAT/rah
Attachment
APPENDIX "A"
Increased Supply Pressure at
Main and Gerrard
Life Cycle Cost Comparison of Alternatives
