Sec. 17-320 Types of development authorized in stream buffer.

D.         Stream crossings of intermittent streams for roads, streets or driveways, provided the following conditions are addressed to the satisfaction of the Program Authority:

1. Culverts or bridges are utilized for the stream crossing and sized to pass the ten year storm without backing water on to upstream properties;  
2. Stream stabilization and energy dissipation below structures is found to satisfy criteria for outlet control and streambank stabilization per the Virginia Erosion and Sediment Control Handbook;
3. The stream disturbance is the minimum necessary to provide access to a developable part of the property.  In general, stream crossings shall not disturb more than thirty linear feet of stream for driveways and 60 linear feet for streets. The Program Authority may allow additional length of stream disturbance where fill slopes necessitate that additional length;
4. The bed and banks of the stream will  be stabilized within seven days of culvert installation or any work in the stream;  and   
5. For stream crossings on properties where the stream buffer is not fully vegetated, other than the stream crossing, buffer vegetation shall be established and maintained at a ratio of two square feet of stream buffer  restored for every one square foot of stream buffer disturbed as part of the stream crossing, up to the point the buffer is fully vegetated outside of the stream crossing.  Stream buffer plantings shall be consistent with guidance supplied by the Program Authority.

E.         Stream crossings of perennial streams for roads, streets or driveways, provided the following conditions are addressed to the satisfaction of the Program Authority:

1. Bridges, arch culverts, or box culverts are utilized for the stream crossing and sized to pass the ten year storm without backing water on to upstream properties.   Bridges or culverts must either leave the stream section undisturbed or return the stream to its natural cross-section upon completion of construction.  Culvert bottoms must be a minimum of six inches below the stream bed.  Culvert walls and bridge columns should be located outside the stream banks wherever possible;    
2. The property owner has provided the Program Authority with copies of approved Federal and State permits associated with the stream crossing, if applicable;
3. Stream stabilization and energy dissipation below structures is found to satisfy criteria for outlet control and streambank stabilization per the Virginia Erosion and Sediment Control Handbook;   
4. The stream disturbance is the minimum necessary to provide access to a developable part of the property.  In general, stream crossings shall not disturb more than thirty linear feet of stream for driveways and 60 linear feet for streets. The Program Authority may allow additional length of stream disturbance where fill slopes necessitate that additional length;      
5. The bed and banks of the stream will  be stabilized within seven days of culvert installation or any work in the stream; and   
6. For stream crossings on properties where the stream buffer is not fully vegetated, other than the stream crossing, buffer vegetation shall be established and maintained at a ratio of two square feet of stream buffer restored for every one square foot of stream buffer disturbed as part of the stream crossing, up to the point the buffer is fully vegetated outside of the stream crossing.  Stream buffer plantings shall be consistent with guidance supplied by the Program Authority.

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