SLIDE 1
Hershey Mill Dam Pond Looking North
Hershey Mill Road
Hershey Mill Dam Pond Looking NE Hershey Mill Dam Pond Looking North - - PowerPoint PPT Presentation
Hershey Mill Dam Pond Looking NE Hershey Mill Dam Pond Looking North - - PowerPoint PPT Presentation
Hershey Mill Dam Pond Looking NE Hershey Mill Dam Pond Looking North Hershey Mill Road Hershey Mill Dam East Embankment Looking Towards Spillway Hershey Mill Dam Embankment East of Spillway Erosion Area Hershey Mill Dam Looking Downstream from
SLIDE 2
SLIDE 3
Hershey Mill Dam East Embankment Looking Towards Spillway
SLIDE 4
Hershey Mill Dam Embankment East of Spillway
Erosion Area
SLIDE 5
Hershey Mill Dam Looking Downstream from East Embankment
SLIDE 6
Hershey Mill Dam Looking Downstream from East Embankment
SLIDE 7
Hershey Mill Dam Looking Downstream from East Embankment
SLIDE 8
Hershey Mill Dam Looking Downstream from East Embankment
SLIDE 9
Dam Upgrades – October 2008
Option 1 – Addition of 200 feet of concrete spillway adjacent to existing stone spillway
Option 2 – New spillway of articulated concrete block (ACB) – (emergency spillway??)
Option 3 – Breach the dam and restore the stream
Sediment testing results
SLIDE 10
Other Options/Discussions
Preserve spillway and viewscape
Pump water over spillway
Appropriate stream restoration
SLIDE 11
Commentary to Township
Cost estimate without detail or apparent contingency
Construction cost elements not defined
Removal/Management of Sediment – possibly $3 to $5/CY w/o Transportation & Disposal
Clamshell
Mudcat
- r Divers
Stream Restoration Costs ‐ up to $1 million/stream mile
Approximately 0.2 to 0.3 stream miles
Wetlands/Habitat
Re‐stocking
Flora/Fauna
SLIDE 12
Potential Dam Restoration Elements
Slope/Wall Stability
Sheetpiling
Remove wall/ extend slope
Rip‐rap against stone wall
Hydraulic
Spillway crest lowering (w/ flashboards or gate)
Embankment armoring
SLIDE 13
Maintenance – Near Term
Tree/ vegetation removal
Repair of eroded/scoured areas
Low outlet valve operational?
Access to Dam
SLIDE 14