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Corridor H and the Cacapon River

Sections of the Corridor H four-lane highway are now being built in the Cacapon and South Branch of the Potomac watersheds. No matter what you think about this highway, now that it is being built our concerns must shift to the impacts of construction on our environment. The biggest initial threat to our rivers is sediment laden runoff from construction sites. 

Our December 2001 Cacapon newsletter has a feature article on the issue of erosion control on highway construction sites.  The following pictures illustrate the construction process and the erosion-control measures, or Best Management Practices, intended to keep the construction site sediment  out of our rivers.

 

 

Clearing - Aerial view looking west from Lost River Valley

 

Getting Started - 

Setting up Construction Offices, Clearing and Grubbing

The process begins by clearing space for construction offices.  Heavy equipment is brought to the site.  Following this, the highway's path is "cleared and grubbed" (i.e.: trees are cut, stumps and pulled, debris is burned).  For those of us with an attachment to certain scenic vistas and places, this phase of construction is the most "apocalyptic."  This is also the phase where erosion control is the most difficult.  Note the silt fences on each side of the stream in the mid-ground area in photo 2.

Aerial view of clearing operationAerial view looking west from Baker

WHY DOES SEDIMENT MATTER?

 

 

Cut and Fill

After the land has been cleared, heavy equipment is used to shape the land, drilling, blasting, cutting and filling to bring the road to final grade.

 

 

Double click on picture "thumbnails" to see full size photograph.

 

 

 

 

 

 

McCauley Area 1/03/02 McCauley_Area_1/03/02

FillingFinal shaping.

Double click on picture "thumbnails" to see full size photograph.

ShapingCutting

Getting StartedHeavy Equipment

Setting up Construction OfficesIt took a lot of fill material to make this road.

Final shapingErosion Control

The scale of highway construction projects creates special challenges for erosion control.  These projects expose a huge amount of acreage to erosion.  Whether cutting, filling or shaping the margins, these sites are in a constant state of change (see above pictures). This activity is particularly dynamic when you build in mountainous terrain.  Black silt-fences and hay bales are little more than band-aids on a gaping wound for a site as large as a four-lane highway.  The builders also have a problem with very fine sediments (in part created by blasting and heavy equipment) that erode easily and remain in suspended in the water for a very long time. 

 Erosion control demands constant attention in order to be effective.  As the road surface is shaped, it is brought up (or down) in such a way that water will flow to the edge. Water flowing along that edge is contained by a low earthen berm and flows to a low spot. At the low spot, a hole in the berm allows the water to flow off the road's surface into a large black plastic pipe, known as a pipe slope drain. The water is carried down that pipe to a sediment pond -- the lynchpin of the entire process.

Worker installs Pipe Slope Drain.

Double click on picture "thumbnails" to see full size photograph.

Black pipe carries water from road surface to sediment pond (not visible).

 

 

Pipe Slope Drain runs from a berm at edge of road....Digging a sediment pond.

...down to a sediment pond.Pipe slope drain on unvegetated slope.

Pipe Slope Drain on vegetated slope.

 

 

 

 

 

 

 

 

Final grade.

 

 

Filling and cutting (drill for blasting in background)

Realistically, you can't build a road like this without losing some sediment.  The following pictures were taken in the Lost River on a  day when a little less than one inch of rain fell in the construction area, and shows how even a fairly small amount of runoff with very fine sediment can muddy the river -- this Lost River pool usually remained "colored" for about 5 days after a runoff event.  

 

 

 

 

 

 

 

 

The sediment ponds and other erosion control "Best Management Practices" on the construction site are required by law to protect the river from the harmful impacts of runoff generated by a 2-year, 24-hour storm in our region that's about three inches of rain in one day. The General Water Pollution Discharge NPDES permit for these projects, issued by WV Division of Environmental Protection, requires the sediment ponds to be sized at 3600 cubic feet per acre of drainage area.  However, we found that the construction documents called for ponds of 1800 cubic feet -- 1/2 the required size.  

The Wardensville-based Stewards of the Potomac Highlands and the West Virginia Rivers Coalition sued WVDOH on the issue of undersized sediment ponds.  After the suit was filed, WVDOH agreed to amend its BMP manual and enlarge sediment ponds on its Baker-Wardensville construction sites to meet the requirements of their permit and other sites around the state.

Lost River at Hanging Rock 7/19/01Lost River at Hanging Rock 7/19/01

 

Lost River at Hanging Rock 7/19/01

 

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Cacapon Institute - From the Cacapon to the Potomac to the Chesapeake Bay, we protect rivers and watersheds using science and education.

Cacapon Institute
PO Box 68
High View, WV 26808
304-856-1385 (tele)
304-856-1386 (fax)
Click here to send us an email
Frank Rodgers,  Executive Director

Website  made possible by funding from The Norcross Wildlife Foundation,  the National Fish and Wildlife Foundation, Virginia Environmental Endowment, NOAA-BWET, USEPA, The MARPAT Foundation, and our generous members.