Conditions Prior to the Weather Event
- Water levels were higher than normal due to the saturated soil conditions and 25-45 mm of rainfall the previous week
- The Surface Water Monitoring Centre advised CAs that there was a large system moving into the area.
- KCCA issued a Watershed Conditions Statement—Flood Outlook on May 3, 2017 at 16:30 EST.
During the Weather Event
- A strong low pressure system with a rich supply of gulf moisture developed in the southern United States and tracked northerly into southern Ontario.
- Early Environment Canada forecast information indicated a potential for rainfall amounts ranging from 40-70 mm over three days.
- Rainfall warning issued for the area on May 3rd at 15:04 EST via the ECAlertMe system.
- Surface Water Monitoring Centre (MNRF) continually updating CAs with new information from the storm tracker.
- Recorded rainfall amounts across the watershed ranged from 44.4 mm to 61.5 mm with highest amounts in Dodd Creek and Upper Kettle Creek subwatersheds.
- Recorded rainfall intensities over the duration of the event were low, ranging from 1 to 3 mm/hr.
- Winds coming off of Lake Erie were not conducive to storm surge conditions over the duration of the event.
[info_message style=”error”]Issued at 2017-05-03 19:04 UTC by Environment Canada: Rainfall warning issued for: London – Middlesex, Ont. (041500) Elgin, Ont. (041600) Woodstock – Tillsonburg – Oxford County, Ont. (041710) Current details: Heavy rain is expected. The ground, already near saturation, has little ability to absorb further rainfall. 40-70 mm of rain expected Thursday through Saturday. Rain will spread into Southwestern Ontario Thursday morning and is forecast to persist into Saturday as the weather system responsible stalls over the region. The rain is expected to taper to showers late Saturday or Saturday night. With the ground already saturated, there is the potential for local flooding. For information concerning flooding please consult your local Conservation Authority or Ontario Ministry of Natural Resources and Forestry District office. Localized flooding in low-lying areas is possible. Don’t approach washouts near rivers, creeks and culverts. Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to ec.cpio-tempetes-ospc-storms.ec@canada.ca or tweet reports using #ONStorm.[/info_message]
Kettle Creek Conservation Authority Actions
- Flood Watch media release issued by KCCA on May 5, 2017 at 10:00 which provided details on the impending rainfall event and information regarding safety and local conditions.
- Continuous monitoring of weather conditions and real-time watershed monitoring of precipitation, water level and flow using the stream gauge and rain gauge network.
- KCCA flood watch team deployed to monitor key areas of historically flood prone locations, as well as continuous monitoring of dams over the duration of the event.
- Ongoing updates to social media of photos, videos to Facebook, Twitter and Instagram.
Watershed Response
Dams and Erosion Control Structures
- Continuous monitoring of Dalewood Dam, Union Dam and Southwold Wall.
- Flows observed moving well over the structures with no major debris or blockages.
Natural Watercourses
- Bankful conditions observed in many urban and rural streams.
- Many historically flood prone areas in the Upper Kettle Creek subwatershed exceeded bankful conditions and extended into natural floodplain areas.
- No debris blockages or overtopping of road crossings were observed.
- No flooding of structures were identified through field observations.
- Ponding of water observed in many agricultural fields.
