Quote:
Originally Posted by jammer139
What has changed since the 1980's that would imply that Lambeth, White Oaks, White Oaks Mall and Exeter Rd is now in the flood plain of Dingman Creek?....I expect the UTRCA will need to explain their rational for expanding the flood plain mapping in technical detail to justify this.
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Climate change has had a significant impact since the 80's. In terms of rainfall intensity/duration standard design curves, events that historically occurred once every 5 years is now a 1 in 2 years event, once in 10 years is now 1 in 5 years, etc. Most design standards for storm sewer capacity are being reviewed and updated in many jurisdictions as a result. Since all of those storm sewers discharge into watercourses, the ability for those watercourses to accommodate potentially significant increases in flow volumes (including their floodplains) would be prudent to review.
As well, the section of Dingman Creek between Wellington Rd. and Lambeth will see significant urban development in the next 20 years. What is now a natural state of precipitation absorption of the soils will be dramatically be altered to having a significant portion being impermeable, significantly altering intake and flow rates of the creek.
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