Flood Mitigation Master Plan
The Flood Mitigation Task Force invited the residents of both the Town of Sussex and the Village of Sussex Corner to hear the studies findings, the recommended flood mitigation plan as well as the return on investment identified at the completion of this review on this important community issue.
Both the Town of Sussex and Village of Sussex Corner have continued to formally engage in the Joint Flood Mitigation Master Planning assessment in both the Town and Village and have completed the necessary tasks to begin the process of securing funds to implement the recommended solutions.
The Flood Mitigation Master Plan Task Force have now completed the refinement of options to address overland / surface water flooding, if and where possible, and have identified mitigation projects to reduce flood impacts for both communities, jointly.
Mayor Wilkins, Mayor Thorne and members of both Councils attended to the review with the public the final Flood Mitigation Master Plan and both Councils believe the flooding events experienced is our issue and the single most important issue faced by each community and its affected properties.
Mitigation Plans:
Sussex Region Flood Risk Mitigation Plan – Final – March 30, 2022
Public Presentation Flood Risk Mitigation Plan – September 10, 2020
Final Plan Public Presentation (SRHS March 30, 2022):
Presentation Agenda – March 20, 2022
Public Presentation Slide Deck- March 30, 2022
Public Presentation Flood Risk Mitigation Plan – Final (March 30, 2022) – YouTube
Scenarios examined:
Scenario 1
In this scenario, the flow into Trout Creek is aggressively limited to the maximum of 10 m3/s (less than 5% of it’s total flow). The number of affected properties reduce by 200, roughly a 57% decline from the easting conditions’ 465 properties. However, the necessary channel size to reduce the flows to such low levels is unrealistically large. Besides the much higher construction costs, acquiring the necessary permits for such a large structure and aggressive flow limit may be more challenging. Furthermore, the water levels at the next biggest area of concern (along Main Street and Skyline Avenue) remain high and unaffected by the diversion channel in this scenario.
Scenario 2
The flow diversion channels from Trout Creek and Parsons Brook carry 160 m3/s and 60 m3/s respectively (73% of Trout Creek and 66% of Parsons Brook’s flow during peak time). The number of affected properties drop to 165, about 65% decrease, and the channel specifications remain within a practical range. The drawback in this scenario is the aggravated flood levels in the area between the Parsons Brook’s diversion outlet and Trout Creek’s diversion inlet. The number of affected properties in this area increase from 54 to 62.
Scenario 3
The two diversion channels from Trout Creek and Parsons Brook carry 40 m3/s and 25 m3/s respectively (82% of Trout Creek and 72% of Parsons Brook’s total flow during peak time). The number of affected properties drop to 133, about 71% decrease. The cannel specifications are larger than the previous scenario by 10% to 15% but still remain within a practical range. Similar to scenario #2, the drawback in this scenario is the aggravated flood levels in the area between the Parsons Brook’s diversion outlet and Trout Creek’s diversion inlet. The number of affected properties in this area increase from 54 to 63.
Scenario 4
A 20m wide channel can transfer up to 120 m3/s (54% of Trout Creek’s maximum flow) from Trout Creek to Kennebecasis River. The flows in Parson Brook remain unchanged. This scenario results in roughly 27% decrease in flood damages. While the channel size and construction costs in this case are very attractive, the reduction in flood damages is low and the return on investment is poor.
Scenario 5
This scenario is a modified form of scenario #2. A few low-cost flow control measures in downtown Sussex can reduce the inundation significantly and increase the return on investment in this scenario. The total number of damaged properties is reduced to 114, about 75% decrease from existing conditions. Similar to scenario #2 and #3, the disadvantage of this scenario is the aggravated flood levels in the area between the Parsons Brook’s diversion outlet and Trout Creek’s diversion inlet. The number of affected properties in this area increase from 54 to 62. The results of this study indicated that scenario #5 may have the highest return on investment among other scenarios.
Existing Conditions
With no diversion channel on Trout Creek and Parsons Brook, their maximum flows during a 1 in 100 years return storm reach 220 m3/s and 90 m3/s, respectively. No flow control measures are in place to prevent inundation, and a total of 465 properties are affected within the study area.
Current Mapping:
GeoNB Flood Mapping Information:
- Link http://www.snb.ca/geonb1/e/index-E.asp
- Under the Applications tab at the top of the page, click the start button on the “Flood Hazzard Mapping”
- Check I agree to the above terms and conditions, bottom left; then click the OK bottom bottom right.
- Click the x to remove the text box on the right.
- In the search function type the word Sussex.
- Under the layer list, choose SNB Property Maps tab, then choose the flooding map tab you wish to view. We are using the 1 in 100 year 2100 map.
Media:
Short video clip on the Unintended Effects of Dredging
We welcome your questions and feedback.
For more information please contact:
Scott M. Hatcher, P. Eng.
Chief Administrative Officer
Phone: (506) 432-4553
Email: scott.hatcher@sussex.ca