Download - Woodglen Lake Dredging and Restoration
Woodglen Lake Dredging and Restoration Department of Public Works and Environmental Services
Project Update, September, 2013
Woodglen Lake: Meeting Agenda
Project Goals and Status Woodglen Lake Conditions Project Overview Site Access and Decanting Basin Restoration Dredging Approaches Streambank Stabilization Lake Habitat Restoration Project Timeline February Meeting highlights Questions and Answers
Project Goals
Restore sediment pool and create in-lake forebay Aesthetics Long-term downstream water quality benefits
Improve lake water quality and habitat Stabilize two stream locations to protect access
road Remove existing decanting basin and provide long
term maintenance improvements
Woodglen Lake: Project Status
Data collection completed Lake dredging and management plan completed Design plans and specifications Preliminary design – completed Final design – current design phase
Permitting Late 2013: complete final design Begin construction in spring 2014
Woodglen Lake Facts
Drainage area = 740 Acres (1.15 square miles)
Lake surface area = 12.5 acres
Sediment pool capacity = 160,000 cubic yards (CY)
Current sediment in lake = 29,300 CY
Estimated annual sediment load = 1,200 CY / year
16.6 feet
29,300 CY
Woodglen Lake: Sediment Depth
Woodglen Lake: Water Depth
Woodglen Lake: Project Overview
Staging Area
Improved access road
Sediment forebay
Lake dredging, shoreline restoration,
lake habitat improvement
Removal and restoration of decanting
basin
Potential reforestation areas
Dredging Approaches
1. Wet Dredging: Mechanically dredge deposited
sediment and haul wet. Normal pool maintained. (Note: This option will still require lake drawdown for a short period of time to build the forebay berms)
2. Dry Dredging: Drain the lake and dry deposited sediment in place prior to hauling
3. Project will be bid out with the option to dredge wet or dry
Partial drawdown option for dry dredging: drawing the lake down by 9 feet would leave a 3.5 acre pool; sediment would be dried in the dewatered section of the lake in place prior to hauling. Approximately 1/2 of the deposited sediment volume would be removed.
Woodglen Lake: Site Access and Staging
Woodglen Lake: Decanting Basin Restoration
Realigned access road and restored
decanting basin
Wet Dredging
General Sequence Establish access and staging areas Conduct dredging utilizing barges Haul wet sediment to disposal site
for drying Pros
Less weather dependent Quicker initial start to dredging Less potential for schedule
extensions or delay Cons
Increased sediment handling effort at disposal area
Potentially higher cost
Dry Dredging (Full or Partial Drawdown)
General Sequence Initiate drawdown of lake Establish access and staging areas Establish diversion channels within lake Conduct dredging
Pros Higher daily sediment removal rates Minimal sediment handling effort at
disposal area Potentially lower cost
Cons Very weather dependent Higher potential for delays due to weather Even with a reduced pool, there will be a
need to relocate/salvage fish
Huntsman Lake Dam Rehabilitation Project Fish Relocation (May, 2013)
Woodglen Lake: Partial Drawdown
Staging Area
A partial drawdown would leave a 3.5 acre pool with a maximum depth of 5 feet with an average depth of 1 to 2 feet.
Approximate volume of sediment to be removed 15,000 CY
Lake Restoration
In-lake forebay Wetland planting Shoreline stabilization Fish habitat Fish stocking
Lake Barton: Fish stocking by Virginia Game and Inland Fisheries
Fish habitat created from salvaged trees
Chesapeake Bay Preservation Areas
Buffer restoration in deficient areas
Woodglen Lake: Shoreline Restoration
Existing Shoreline Condition
Woodglen Lake: Shoreline Protection
Image Courtesy of North Fork Native Plants
Fish Habitat Structures
Photos Courtesy of the Pennsylvania Fish and Boat Commission
Nesting Structure
Porcupine Crib Jr. Rock Rubble Piles
Post Clusters
Stream Stabilization
North Stream Stabilization Area
South Stream Stabilization Area
Stream Stabilization
Log Vane
Geolift
Imbricated Rock Wall
Access During Construction
Pedestrian access to lake from Zion Drive will be maintained (after hours)
Lake Barton example
Woodglen Lake: Project Status and Timeline
Data collection completed Lake dredging and management plan completed Design plans and specifications Preliminary design – completed Final design – current design phase
Permitting Late 2013: complete final design Begin construction in spring 2014
Woodglen Lake Dredging and Restoration Project Timeline
Early 2014: construction bid advertisement Spring 2014: begin dredging Dredging method will depend on bid results Project duration: 6 to 7 months
February Meeting Discussion Highlights
Dry/Wet dredging: in order to ensure a competitive bidding environment, both options have to be allowed, with partial drawdown an option for dry dredging
Cheapest dredging method: depends on disposal site identified, either method could be cheaper
Project cost-effectiveness: forebay and maintenance enhancements make this project cost-effective from the viewpoint of downstream water quality improvements and long-term costs
Huntsman Lake (29 acres)
Woodglen Lake Dredging and Restoration
Contacts
Dipmani Kumar, Project Manager 703-324-4612 [email protected]
Matt Meyers, Branch Chief 703-324-5651 [email protected]
Partners:
