To determine the values of the streams over which Corridor H would cross, trained WVDOH and consultant stream biologists use the US EPA's Rapid Bio-assessment Protocols for Use in Streams and Rivers-Benthic Macroinvertebrates Level II. This method rests on the proven theory that different taxonomic groups of invertebrates that live in the water are indicators of water quality.

Streams in the project area range from those with values that have been impaired by agricultural run-off and erosion caused by livestock to high value streams supporting native trout. Surprisingly, 50-60 years ago many of the high value streams in the project area were silt laden and of low value. Intense logging activities and erosion turned the streams into silt conduits. Thanks to the forest reclamation activities beginning in the 1930's, these streams have recovered.

Data was obtained and analyzed from over 200 sample points. During this phase, data was collected on ambient physical, chemical and biological conditions of each stream. Macroinvertebrates were collected, returned to the laboratory and identified. Ninety-three macroinvertebrate families and 13,241 individuals were identified. Details on data collection and data analysis are found in the Streams Technical Report.

This information was utilized to develop and identify mitigation measures during design and construction. For example, during final design activities, engineers perform complex hydraulic calculations to determine if a bridge is required over the stream or if the stream can be crossed by enclosing it in a pipe or culvert. Bridges are obviously more expensive but they do not disturb stream bottoms. Because of its commitment to develop an environmentally sensitive highway, WVDOH used the streams data collected to determine that four additional bridges and four open bottom box culverts would be constructed over streams where hydraulic analyses had determined that cheaper pipes or culverts would be all that was required.

Measures Taken to Avoid Stream Relocations

Regional Project Watershed	Stream Avoided	Measure Taken	Station	Impact Avoided meters/feet	Comments
Tygart River	Leading Creek	Retaining Wall	573	122/400	WVHQ
Tygart River	Leading Creek	Increased Slopes	620	152/500	WVHQ
Cheat River	Trib. to Roaring Run	Increased Slopes	3725	335/1,100
North Branch of Potomac	Trib. to Elklick Run	Shifted Construction Limits	5230	335/1,100
North Branch of Potomac	MF of Patterson Creek	Retaining Wall	5565	320/1,050
North Branch of Potomac	Thom Run	Increased Slopes	5650	305/1,000
North Branch of Potomac	Toombs Hollow	Retaining Wall	5950	137/450
North Branch of Potomac	Williams Hollow	Increased Slopes	6340	366/1,200
Cacapon River	Trib. to Long Lick	Increased Slopes	6830	85/280
Cacapon River	Baker Run	Changed Vertical Grade	6950	427/1,400
		Total		2,585/8,480

AMD = Acid Mine Drainage; NRI = Nationwide Rivers Inventory; WVHQ = WV High Quality Stream; OSRW = VA Outstanding State Resource Waters

The four "new" bridges alone avoided enclosing 3,760 feet of streams at an additional cost of $27.4 million.

Additional Avoidance and Minimization Measures Developed Following Field Reviews

Regional Project Watershed	Stream	Measure Taken	Station	Stream Impact Reduction meters/feet	Comments
Cheat River	Trib. to Roaring Run	Steepen slopes to reduce length of pipe	3731	76/250
Cheat River	Big Run	Replace box culvert with 350 ft. bridge	3925	274/900
Cheat River	Middle Run	Change in grade reduces culvert length	4055	8/25
North Branch of Potomac	Abrams Creek	Increase slope to reduce length of culvert	5029	15/50	AMD
North Branch of Potomac	Trib. to Elklick Run	Replace box culvert with 650 ft. bridge	5293	137/450
North Branch of Potomac	MF of Patterson Creek	Replace box culvert with a 1,200 ft. bridge	5534	427/1,400
North Branch of Potomac	Trib. to Patterson Creek	Shifted line and reduced length of box culvert	5850	76/250
South Branch of Potomac	Clifford Hollow	Replace box culvert with a 1,200 ft. bridge	6515	308/1,010
		Total		1,321/4,335

AMD = Acid Mine Drainage; NRI = Nationwide Rivers Inventory; WVHQ = WV High Quality Stream; OSRW = VA Outstanding State Resource Waters

Many other mitigation measures were developed to assure protection of streams within the project area. Details are found in the Mitigation Document adopted for the Corridor H project.
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