Attachment to Lawrence H. Hale letter written to Vincent P. Profy:
YARDLEY FLOOD WORKSHEET, SEPTEMBER 7, 2006
Ref: Vince Profy and Larry Hale, discussion/walk, from Metz Apts along River to Railroad, through Belmondo to Lock 5, along Canal to Upper Borough Line, down Morgan Ave, Brown Street, Brock Creek Bridge, Funeral Home, N. Bell Ave, crossing College Ave, down Longshore
Our objective here is to identify as many of the elements of the flooding problem as possible and assemble them into some sort of framework.
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Table 1 |
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| I | Existing Homeowner Lots |
| II | 100-Yr Flood Area Between Lock 6 and the Railroad |
| III | Local Creek Watersheds (Yardley & Lower Makefield) |
| IV | Delaware Valley Watershed (PA, NJ, NY) |
I - Existing Homeowner Lots (a) Elevation – "item of choice for mitigation" in low areas (b) Flood Proofing (c) Other
II – 100-Yr Flood Area Between Lock 6 and the Railroad (a) Canal (b) Sub-Area "A" - "Pennsylvania Ave & Vicinity" (c) Sub-Area "B" (d) Sub-Area "C"
III - Local Creek Watersheds (Yardley & Lower Makefield) (a) Brock Creek (b) Silver Creek (c) Other
IV – Delaware Valley Watershed (PA, NJ, NY) 1) Corrective Actions (Lower the crest of the 2005 flood): Action "A" = 1-ft Action "B" = 1-ft Action "C" = 1-ft, etc. 2) Corrective Actions expressed in terms of 25-yr, 50-yr, 75-yr floods 25-yr 50-yr 75-yr Action "A" Action "B" Action "C"
This article is limited to certain parts of the flooding problem in Yardley. I have not looked at or identified the countless possible corrective actions that might be undertaken under Categories IIIand IV.
Table 1 can be expanded into a large number of sub-categories, and each of these further expanded into a large number of elements. It's just a way of figuring out what questions to ask and keeping track of the answers... identifying various possible corrective actions, quantifying each one, and seeing how that specific corrective action interrelates with other possible corrective actions. A modest reduction in the height of the flood on the river can make a significant difference when combined with other corrective actions, for example along the canal.
Example: Under Category II, Sub-Area "Railroad Impoundment" (the area between the Canal & Longshore Ave and between College Ave and the Railroad) the following components of the system can be targeted for corrective action. I've itemized them here based on location of incoming and outgoing floodwaters. 1) Incoming canal breach 2) Incoming overland flow 3) Outgoing Lock 5 bypass 4) Outgoing Letchworth storm drainage system 5) Outgoing spillway diversions 6) Outgoing railroad underpass below Lock 5
100-YEAR FLOOD
The 100-year flood level is an illusive concept, which involves a lot of variables. The Base Flood Elevation (BFE) is the actual fixed elevation used for "building elevation" purposes. The BFE is a somewhat arbitrary number. It's one of those cases where a line (in this case an elevation) has been drawn... you are either above or below the designated elevation no matter the actual vertical distance between you and the 100-yr or lesser floods. It's a device used by regulatory agencies dealing with large areas of land. Once a homeowner has made the decision for "elevation" it is no longer necessary to search for 1) ways of protecting against lesser floods or 2) corrective actions which reduce the flood level, at least as relates to your own property. There's no doubt that the BFE serves as a useful compromise for planning, design, insurance purposes and it's the legal requirement for "building elevation." However, fixation on the 100-yr flood may impede innovation and creativity in finding ways to reduce the flood level, and doesn't help homeowners who can't afford to elevate.
Elevation is undoubtedly the "item of choice for mitigation" in the lowest areas, but most homes between the canal and the river are on somewhat higher ground ---levels actually vary as much as 10 feet. This article is focused on those homes.
BASEMENT FLOODING
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Elevating Utility Rooms – this example appears to be applicable to hundreds of homes between the canal and the river. In certain cases and maybe in a lot of cases, it might provide a cost effective approach, where adding one room to a house would significantly reduce flood damage, and at many locations completely eliminate flood damage from recent floods.