Watershed: A Turning Point
Remembering the City of Peterborough's historic flooding event of 2004
The Watershed
Only one hour north-east of Toronto and three hours west of Canada's capital, Peterborough emerges as a vibrant city brimming with historical charm and natural splendor. Peterborough finds itself nestled amidst the picturesque landscapes of Kawartha Lakes region, just on the edge of the wild Canadian Shield.
Since as far back as the 1600s, the traditional Anishinaabeg Indigenous group has met on these lands and call this area Nogojiwanong, Ojibwa for “place at the end of rapids". The reason for fast-flowing water was the steeper surrounding topography combined with those Kawartha Lakes fueling the river system. These rapids flow along the Otonabee River, the largest river bisecting the city north-southwards. Along this river's banks are relatively flat, fertile plains; this is due to a much larger floodplain forming at the last glaciation period. Surrounding these flatlands are hundreds of tear-drop shaped hills known as drumlins, which were also created by the Laurentian Ice Sheet 10,000 years ago. These numerous hills, combined with the flat grasslands and high water table leave the area of Peterborough vulnerable to flooding events.
As the City of Peterborough began to grow in population, settlement began to take place within the hill valleys and pre-existing floodplains. While these lands are easy to build upon, they are prone to flood events during precipitation or changes in season. Within the current city limits, there are 8 main watercourses that accumulate water runoff and drain into the Otonabee River. In total, 4 of these watercourses exist on the west side of the Otonabee: Riverview Creek, Bears Creek, Jackson Creek, and, Byersville Creek. Jackson Creek is the largest of the western creeks, running through the downtown core and discharging into Little Lake.
City of Peterborough's "Our Watershed" is an interactive map experience that showcases these different geographical features and systems in the region explained above. Using the "map layers" box, toggle these factors to understand how these pre-existing conditions may have caused significant flood events. Additionally, use the three links located on the bottom of the screen to learn more about the City's watershed planning commitments and previous media.
The combination of these conditions set the stage for the potential of flood events, given the perfect storm.
The Rain
On the morning of July 14th, 2004, a low-pressure system moved into southwestern Ontario. The warm moist air ahead of the cold front was being occluded (where a cold front pushes warm air upwards). Between July 14th and 15th, this low-pressure system dominated all of southern and eastern Ontario, with a cold low aloft that had become stationary over the City of Peterborough. This unstable air mass produced a series of thunderstorms with associated heavy rainfall.
At 3:30 pm today, MNR advised us of the potential for heavy rainfall overnight. Amounts predicted are from 40 - 70mm. It's a slow moving storm system with the possibility of thunderstorms. We issued a Watershed Conditions Bulletin at 4:20pm.
The rainfall received was unprecedented for the City. The majority of rainfall fell in an uninterrupted 10 hour period between 10pm on July 14th and 8am July 15th. During this period, the highest recorded rainfall occurred in the area of Trent University which received 220mm of rain (250mm total).
Rainfall recordings were documented all across the City using a variety of technologies including, official Environment Canada weather stations, City operated rain gauges, citizen owned rain gauges, and simple bucket surveys. As shown in the map attached, rainfall depths varied across the City from a low of 115mm to a high of 250mm.
To further interact with the map, use zoom levels to see the full extent of rainfall coverage. Additional information about each weather station can be found by clicking each point. NOTE: Rain measurement sites are categorized via A, B, or C. This reflects level of reliability due to instrumentation and agency ownership.
The Flood
The extreme amount of rainfall received overwhelmed the City's drainage infrastructure resulting in significant damages to both public and private property. Across the City, residents woke up to flooded basements, roads turned to rivers and, in some areas, the earth washed away by flowing waters. Estimated damages to both private property and infrastructure was in excess of $100 million.
There were four primary factors that contributed to the significant flood damages, these included:
- Unprecedented heavy rainfall of an intensity of more than twice the current design standard used by most municipalities, centered on the largely paved downtown core, resulting in high runoff.
- Insufficient storm sewer capacity caused by undersized pipes that were never designed to handle this volume of rainfall.
- Poorly defined overland flow routes caused by filling and redirecting natural waterways over time without accommodating the water elsewhere.
- Unwanted water getting into the sanitary sewer system leading to system overflow and backups caused by foundation drains and roof leaders connected to the sanitary sewer, as well as aging pipes and pipe blockages.
Taken by various sources, the Map Tour below displays the far-reaching extent of this rain event and the damages it caused. Select any point on the map or the various City location's photo cards to see before/ normal conditions, and the same location during the flood event.
Significant flooding in the Downtown Core occurred where Jackson Creek, normally hidden from view below our feet, exceeded the confines off its banks and spread across the streets of downtown. The map attached was produced by Otonabee Conservation with a water-systems computer model, and estimates the extent of flooding from Jackson Creek resulting from the rainfall received in July 2004.
The Response
On the morning of July 15th, 2004 then Mayor Sylvia Sutherland declared a State of Emergency, which stayed in effect until July 30, 2004. The flood sparked a profound community response marked by resilience and solidarity. Hundreds of homes across the City suffered damages from the extreme rainfall, and residents swiftly mobilized to assist those affected.
Volunteers, together with emergency personnel, supported the cleanup and delivery of essential services and supplies. The flood not only tested the City's infrastructure but also highlighted the strength of our community and collective commitment to preparing for future climate challenges together.
In addition to the immediate emergency response, the flood triggered a series of actions taken by Council and City staff in the coming months, these included:
- A Capital Budget and discretionary operating budget freeze
- Application to the Ontario Disaster Relief Assistance Program
- Emergency purchasing policy put into effect to fast track repairs and restoration
- Establishment of a Flood Committee and various subcommittees
- Consultant retained to prepare an analysis of the City's drainage system (Flood Reduction Master Plan)
The Plan
Show me a healthy community with a healthy economy and I will show you a community that has its green infrastructure in order and understands the relationship between the built and the unbuilt environment.
Completion of the Flood Reduction Master Plan was a pivotal moment for the City's residents, staff and Council. The Master Plan laid the groundwork for a significant investment in infrastructure to reduce flooding and respond to a changing climate, long before many were concerned with the impacts of climate change.
Subsequent to the Master Plan being completed, the City took a number of steps in the coming years to establish a robust flood reduction program. This included a strong commitment from Council to earmark up to $5 million annually to implement the flood reduction capital program. This funding has varied slightly over the years due to competing priorities, nevertheless, since 2005 the City has invested $82.4 million to implement the recommendations of its Flood Reduction Program.
The flood reduction capital program was the result of a number of watercourse specific flood reduction studies which resulted in a list of over 100 capital projects. All of these projects were aimed at reducing the flood risk and damages resulting from a major rainfall event. In addition, the flood reduction program would support the ongoing inspection, cleaning, and rehabilitation of the City's sanitary sewer system.
The City's completed flood reduction capital projects can be explored on the map attached. These capital projects had a total construction value of approximately $42.5 million (flood reduction component only), but result an estimated $125 million in avoided flood damages. In addition, the City's capital program includes annual funding for flushing and cleaning storm and sanitary sewers, as well as sewer maintenance and repairs that extend the service life. Approximately $2.5 million is allocated annually to this critical work that significantly reduces the risk of sewage overflows and backups into residents basements.
For mobile users, click the link above to view the Water Resources Capital Project Map Viewer.
Program Name | Capital Cost ($) | Year Completed |
|---|---|---|
Rainfall Monitoring | 110,000 Annual Budget | Ongoing |
CCTV Inspection | 1,350,000 Annual Budget | Ongoing |
Inflow and Infiltration Studies | 535,000 | 2013 |
Storm Sewer and Watercourse Flood Reduction EA's | 2,100,000 | 2005 - 2012 |
Watercourse Management Plans | 125,000 | 2006 - 2014 |
Sewer Maintenance Plans | 1,750,000 Annual Budget | Ongoing |
Public Awareness And Support (Flood Reduction Subsidy) | 66,000 Annual Budget | Ongoing |
Detailed Sanitary Sewer EA Inflow and Infiltration Reduction | 550,000 | 2012 |
Table 1: Stormwater and Sanitary-Sewer Capital Programs currently being undertaken by The City of Peterborough
