woodglen lake dredging and restoration

Woodglen Lake Dredging and Restoration Department of Public Works and Environmental Services

Woodglen Lake Facts

Lake Surface Area = 12.5 acres

Sediment Pool Capacity = 160,000 cubic yards (CY)

Current sediment in lake = 32,500 CY

Estimated annual sediment load = 1,244 CY

17 feet

32,500 CY

Watershed

Drainage Area = 740 acres (1.15 square miles)

Pohick Creek Watershed

Sideburn Branch

Woodglen Lake

Woodglen Lake: Sediment Thickness

Woodglen Lake: Water Depth

Inactive Dewatering Basin

Woodglen Lake: Dewatering Basin

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Lake Restoration and Dredging Project

Project Goals

Restore sediment pool capacity

Downstream water quality benefits

Lake water quality

Esthetics

Improve lake water quality and habitat

Stabilize stream segment

Provide long term maintenance improvements

Dredging Alternatives

1. Mechanically dredge deposited sediment and haul wet

2. Drain lake and dry deposited sediment in place before hauling

PRE-DREDGING: An estimated 35,000 cubic yards of sediment had accumulated in the lake, forming islands and reducing water levels to less than three feet in most areas.

Lake Barton Example

Lake Barton Example: Pre-Dredging

Lake Barton Example: Dredging in Progress

DREDGING: Dredging took place without draining the lake.

Lake Barton Example: Dredging in Progress

Lake Barton Example: Completed Project

Lake Needwood Example

Lake Needwood: Montgomery County, MD

Dredging: The lake was drained and the sediment was dried in-place.

Lake Needwood Example: Dredging

Dredge Alternative – In the Wet

General Sequence Establish access and staging areas

Conduct dredging utilizing barges

Haul wet sediment to disposal site for drying

Benefits Less weather dependent

Quicker initial start to dredging

Less potential for schedule extensions or delay

Concerns Increased sediment handling effort at disposal area

Potentially higher cost

Dredge Alternative – In the Dry

General Sequence Initiate drawdown of lake Establish access and staging areas Establish diversion channels within lake Conduct dredging

Benefits Higher daily sediment removal rates Minimal sediment handling effort at disposal area Potentially lower cost

Concerns Very weather dependent Higher potential for delays due to weather Typically more odor from entire lake bottom being exposed Need to relocate/salvage fish

Dredging: 32,500 Cubic Yards

Woodglen Lake

Staging Area

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

Woodglen Lake: Shoreline Restoration

Woodglen Lake: Shoreline Restoration

Woodglen Lake Existing Conditions

Shoreline Protection Options

Fish Habitat Structures

Stream Stabilization

Woodglen Lake: Site Access & Staging

Access During Construction

Lake Barton

Huntsman Lake

2011

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Woodglen Lake

Woodglen Lake Dredging and Restoration Project Timeline and Coordination

Community coordination at Design and Construction phase

June 2013: Final Design

July 2013: Construction bid advertisement

September/October 2013: Begin dredging

Project duration: 6 - 7 months

Lake may be drained for entire project (dredging method depends on project bidding) Partial lake drawdown alternative to be evaluated

Woodglen Lake Dredging and Restoration

Contacts

Dipmani Kumar, Project Manager 703-324-4612

Dipmani.kumar@fairfaxcounty.gov

Matt Meyers, Branch Chief 703-324-5651

Matthew.meyers@fairfaxcounty.gov

Partners: