Cooks Run and Veterans Lane Floodplain analysis and reconstruction

1. Reconstruction of
Veterans Lane and
its Impact on the
Floodplain
By: Mark Mayhew, PE
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2. 1. Development – Overview
2. Cooks Runs – Veterans Lane
3. Raising Roadway – Modeling
4. Flood Storage
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3. 1. Development – Overview
• 19.2 acre abandoned manufacturing site SFH to north,
apartments to east, shopping & multi-story age-
restricted housing to south.
• GPH proposed 117 unit neo-traditional housing with
73,000 sf office/commercial
• One detention basin proposed within commercial
section
• Site traversed by twin 24” gas mains.
• Cooks Run flows east to west along southern property
line.
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5. Cooks Run
• The Site was traversed by approximately 800 lf of
Cooks Run, a tributary to the Neshaminy Creek.
• It was also transected by two Texas Eastern gas pipe
lines and existing water and sanitary lines.
• The floodplain of Cooks Run had been significantly
impacted by prior site development over the past years.
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6. FEMA Flood Insurance Rate Map
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7. Veterans Lane
• Veterans Lane runs along the banks of Cooks
Run with only 20 to 40 feet separating the stream
and the roadway curb line.
• The roadway flooded frequently, as much as 1’
during the 2-yr storm and over 3’ during the 100-yr storm.
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9. Cooks Run Pre-Construction
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10. Cooks Run Pre-Construction
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11. Cooks Run Pre-Construction
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12. Existing Culvert
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13. Lantern Hill, Doylestown, PA
• Granor Price Homes’ Lantern Hill development was
conditioned upon GPH reconstructing and raising a
portion of Veterans Lane.
• Raising the roadway would add fill to the floodplain,
potentially impacting adjoining properties.
• GPH, TWT, the Borough and adjacent property owners
joined together to actually lower upstream flood
elevations.
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14. 3. Model Roadway
• Analysis of existing relief
(area was not over roadway)
• Analysis of proposed roadway
(develop stage – discharge)
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16. Stormwater Calculations
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17. Veterans Lane Plan View
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18. Veteran’s Lane Profile
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22. Floodplain Delineation Plan
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23. Cooks Run - Construction
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24. Cooks Run - Construction
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25. Cooks Run - Construction
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26. Post-Construction
• The roadway was raised approximately 3 feet.
• The far bank was excavated to recreate a wetland
flood-fringe.
• Five, 24” RCP cross drains were installed under the
raised roadway to allow the floodwaters to move under
the roadway.
• The water would eventually drain back into the stream
when the floodwaters receded.
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27. Cross drains during construction
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33. 4 Flood Storage Plan
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34. 4 Flood Storage Plan (cont.)
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35. Cooks Run – Wetland Area
Post-
Construction
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36. Cooks Run – Wetland Area
Post-
Construction
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37. Construction of the wood bridge over Cooks Run
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38. Detention Basin at Lantern Hill
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39. Taylor Wiseman & Taylor
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