Probabilistic Program

The biological communities living in West Virginia streams are exposed to stressors, including contaminants, sedimentation, nutrient enrichment, and acidity. 

The WVDEP uses benthic macroinvertebrates to assess the biological condition of streams in the state. 

Measures of benthic macroinvertebrate communities are assessed through family-level and genus-level based indices of biotic integrity. The IBIs’ metrics compare biological samples to reference conditions. 

The Aquatic Life Criteria Attainment Threshold (ALCAT) uses genus-level data to determine attainment. A technical memorandum describing ALCAT can be found in Appendix B of the Integrated Report.

*Based on the ALCAT percent of threshold (where scores <100 are not attaining and >= 100 are attaining)* 

On a statewide scale, 68.1% of wadeable stream miles are attaining for aquatic life use, 30.4% of stream miles are non-attaining, and 1.5% are non-comparable.

Ecoregion

Percent Stream Miles attaining the Aquatic Life Use

Ridge and Valley (66/67) - 84.1% attaining (highest percentage)

Central Appalachians (69)- 67.3% attaining

Western Allegheny Plateau (70)- 60.7% attaining

Basin

See Charts Below

pH (S.U.) is a measure of water’s acidity or basicity and is one of the most influential properties of water.

As pH levels fall below 6.0 or rise above 9.0, physiological stress occurs in many aquatic organisms. Lower pH levels (increasing acidity) may heighten the toxicity of ammonia and many metals.

In WV, acid precipitation and acid mine drainage are the most common causes of low pH acidic waters.

High pH waters may be the result of:

• naturally alkaline rocks and soils leaching into streams and may be exacerbated by physical disturbances such as tilling, mining, and construction,

• treatment for acidic streams using alkaline materials, and/or

• high photosynthetic activity, which removes carbon dioxide from water and raises pH.

For attainment, West Virginia water quality standards states that pH should have “no values below 6.0 nor above 9.0. Higher values due to photosynthetic activity may be tolerated.” (47CSR2 §8.24)

An evaluation of statewide probabilistic data indicates that approximately 95.9% of the stream miles in WV are attaining the pH criterion.

Only 4.1% of the stream miles in the state are non-attaining, with pH values below 6.0.

Ecoregions

Percent Stream Miles impacted by pH

Ridge and Valley (66/67) - 2.8% impacted

Central Appalachians (69)- 8.3% impacted 

Western Allegheny Plateau (70)- 0.0% impacted

It should be noted that the Central Appalachians are where the majority of Acid Deposition in WV has been documented.   

Basin

See Charts Below

Streams receiving mine drainage may contain sulfate concentrations above background levels

A sulfate concentration greater than 50 mg/L was used to identify probabilistic sites influenced by mine drainage. 

In WV, approximately 15.6% of the stream miles statewide are influenced by mine drainage. 

Ecoregions

Percent Stream Miles influenced by mine drainage

Ridge and Valley (66/67) - 2.5% influenced

Central Appalachians (69)- 27.3% influenced 

Western Allegheny Plateau (70)- 9.2% influenced

Basin

See Charts Below

Bacteria samples are analyzed as elevated levels can indicate a human health risk and may correlate with nutrient enrichment resulting in excessive algal growth. 

Many West Virginia streams contain elevated levels of fecal coliform bacteria. 

Contributors to the problem include:

• leaking or overflowing sewage collection systems, 

• homeowner sewage discharges from failing septic systems, and 

• runoff from urban or residential areas and agricultural lands with livestock. 

Based on statewide probabilistic data, 17.5% of stream miles in WV have fecal coliform bacteria levels that exceed the criterion of 400 colonies/100mL. 

Ecoregions

Percent Stream Miles exceeding the WV criterion for bacteria

Ridge and Valley (66/67)- 6.3% non-attaining

Central Appalachians (69)- 14.0% non-attaining

Western Allegheny Plateau (70)- 27.2% non-attaining

*The Western Allegheny Plateau tends to have a higher population density and broader agricultural land cover than the two other ecoregions.*

Basins

See Charts Below

*WVDEP’s probabilistic monitoring is performed at baseflow conditions. Since samples are not collected during storm runoff events, bacteria levels that may increase under these higher flow conditions are not represented in the data.

Nitrogen (N) is a critical constituent of proteins and nucleic acids in all living organisms. 

It is an essential nutrient for growth in aquatic plants and algae. 

Excess nitrogen concentrations in aquatic environments can stimulate excess algal growth. 

Total nitrogen (TN) measures the amount N from all nitrogen forms. These include nitrite (NO2-), nitrate (NO3-), ammonia nitrogen (NH4+), and organic nitrogenous compounds. 

Elevated nitrogen concentrations often result from: 

• fertilizer runoff, 

• animal wastes, 

• wastewater discharges, and/or

• atmospheric deposition.  

An evaluation of statewide probabilistic data indicates that approximately 85.8% of the stream miles in WV are Excellent to Very Good in terms of TN concentrations, 10.1% are Good to Fair, and only 4.1% are Marginal to Poor.

Ecoregions

Percent Stream Miles in Excellent to Very Good condition for Total Nitrogen

Ridge and Valley (66/67)- 75.9% 

Central Appalachians (69)- 84.2% 

Western Allegheny Plateau (70)- 92.7% 

Basins

See Charts Below

Phosphorus (P) is a highly reactive, non-metallic element and an essential nutrient for all living organisms.

Phosphate minerals are the most common form of phosphorus.  Small increases in available phosphorus can cause substantial increases in algal growth.  

Like nitrogen, streams enriched with excess phosphorus may exhibit:

• low dissolved oxygen concentrations, 

• overabundances of filamentous algae and diatoms, and 

• frequent aquatic life kills, including fish. 

Based on a statewide scale, an estimated 73.2% of stream miles are Excellent to Very Good in terms of TP levels, and 16.6% are Marginal to Poor.

Ecoregions

Percent Stream Miles in Excellent to Very Good condition for Total Phosphorus

Ridge and Valley (66/67)- 86.7% 

Central Appalachians (69)- 78.7% 

Western Allegheny Plateau (70)- 60.1% 

Basins

See Charts Below

The Total Habitat Score has a max score of 200 points.  For this report, habitat quality is Excellent to Very Good if the Total Habitat Score is 200-151, Good to Fair if 150-101, and Marginal to Poor if 100-0.

Based on probabilistic data, 24.2% of stream miles statewide have Excellent to Very Good habitat quality, 67.4% of stream miles have Good to Fair habitat quality, and 8.4% of stream miles have Marginal to Poor habitat quality.

Ecoregions

Percent Stream Miles in Excellent to Very Good condition for Total Habitat Score

Ridge and Valley (66/67)- 34.2% 

Central Appalachians (69)- 38.1% 

Western Allegheny Plateau (70)- 3.5% 

Basins

See Charts Below

Excessive sediment in streams may have significant negative effects on instream habitats and the biological communities that use them.  

Interstitial spaces used by aquatic life for cover, feeding, and reproduction are often filled when sedimentation rates are high.  

Two of the most common sediment particles documented in WV streams are

• Sand

• Silt  

Soil erosion is the most common source of sediments and is natural to some degree.

Soil erosion is made worse by human disturbances and activities such as: 

• • • Roads 

    • Construction projects 

    • Logging 

    • Oil/gas extraction

    • Farming

    • Various types of mining  

Based on statewide probabilistic data, 7.0% of stream miles are in Excellent to Very Good condition in terms of sedimentation, 48.2% are Good to Fair, and 44.9% are Marginal to Poor. 

Ecoregions

Percent Stream Miles in Excellent to Very Good condition for Sediment

Ridge and Valley (66/67)- 18.4% 

Central Appalachians (69)- 8% 

Western Allegheny Plateau (70)- 0% 

Basins

See Charts Below

One of the most important problems facing West Virginia streams is the relative presence of embedded sediment.

Embeddedness measures the extent to which rocks (gravel, cobble, and boulders) are covered or sunken into the silt, sand, or mud at the bottom of the stream. 

Fish and macroinvertebrates use the surface area of the stream bottom for:

• shelter

• spawning

• egg incubation

Generally, as rocks become embedded, the available surface area is decreased. 

Embeddedness is primarily rated in the erosional areas of a stream where there is fast moving water.

Based on probabilistic data, 11.7% of stream miles statewide are in Excellent to Very Good condition, 60.2% are Good to Fair, and 28.1% are Marginal to Poor for embeddedness of sediment. 

Ecoregions

Percent Stream Miles in Excellent to Very Good condition for Embeddedness

Ridge and Valley (66/67)- 27.1% 

Central Appalachians (69)- 13.6% 

Western Allegheny Plateau (70)- 1.7% *This is likely because this ecoregion has slower, low-gradient streams, has more erodible soils, and more land-disturbing activities than in other areas.* 

Basins

See Charts Below

Riparian Vegetation: 

• Provide shade

• Create a more stable stream bank

• Minimize the amount of sediment, excess nutrients and other pollutants entering the stream

• Help reduce floodwater velocity

This indicator rates riparian zones on the amount of undisturbed vegetation present.

For streamside riparian zones, the most desirable situation includes:

• Large native trees in the canopy 

• Smaller native trees and shrubs in the understory & 

• Native herbs/grasses with leaf litter for ground cover

Examples of poorly maintained riparian zones are well manicured lawns mowed to the water’s edge and parking lots with no trees or shrubs.

Statewide, 32.6% of stream miles have Excellent to Very Good riparian zones and 36.9% have Marginal to Poor riparian zones. 

Ecoregions

Percent Stream Miles in Excellent to Very Good condition for Riparian Zones

Ridge and Valley (66/67)- 44.1% 

Central Appalachians (69)- 45.3% 

Western Allegheny Plateau (70)- 12.5% 

*The Western Allegheny Plateau has a higher population density and lower percentage of publicly owned land than the mountainous Central Appalachian and Ridge and Valley ecoregions. These two factors help explain the differences in Riparian Vegetative Zone Width between the ecoregions.*

Basins

See Charts Below

The Aesthetic/Trash Index is a measure of the amount of trash that is in and around the stream including that could be washed into the stream at high flows.  

Increased trash in streams can have negative impacts on recreation, tourism, and the economy. 

When it accumulates in or near a community, it may create health and safety risks for those living there. 

Trash pollution can cause damage to aquatic habitats and potentially release pollutants that are toxic to aquatic life.  

Based on probabilistic data, 42.8% of stream miles statewide have little to no trash in them and are in Excellent to Very Good condition, 36.3% are Good to Fair, and 20.8% are Marginal to Poor.

Ecoregions

Percent Stream Miles in Excellent to Very Good condition for Aesthetic/Trash Index

Ridge and Valley (66/67)- 61.9% 

Central Appalachians (69)- 49.7% 

Western Allegheny Plateau (70)- 25.4% 

Basins

See Charts Below

Basins

The Upper Kanawha basin has the least trashy conditions with 71.0% of stream miles Excellent to Very Good and only 9.6% Marginal to Poor.

The Potomac basin was also relatively clean in terms of trash abundance with 60.2% of stream miles rated Excellent to Very Good and only 7.5% rated Marginal to Poor.

Trash was most abundant in streams of the Lower Ohio basin with 46.3% of stream miles rated Marginal to Poor and only 27.6% Excellent to Very Good.