9. BUFFERS AND PERENNIAL STREAMS

9.1 Buffer Design and Waste Structure Setbacks

Buffers must be established in accordance with NRCS technical standards unless specifically established in the EMC rules (15A NCAC 2H .0217) or in statutes. Setbacks for structures must be measured from the toe of the impoundment to the edge of perennial waters. Setbacks from the land application site must be measured from the areas on the fields where waste is applied (wetted area).

The USGS uses blue or purple lines on topographic maps to denote field ditches and canals as well as perennial streams. The 2H .0200 buffer requirements only apply to perennial streams and use USGS maps as some evidence of the location of these streams. USGS maps show ditches and canals as "straight" blue lines. If the lines are not exactly "straight", the waters have been determined to be a stream rather than a canal or a ditch. The lines can be either a single straight line or a series of straight lines connected at angles. While the angle of connection is normally 90°, they can also be at other angles.

For possible consideration for a buffer exemption, a technical specialist can only evaluate straight lines to determine that a stream shown on an USGS map is perennial water. While generally straight lines denote a canal or ditch that does not require a buffer, the technical specialist still has the responsibility to make an "on site" determination.

Use the following guidance to assist in making an "on site" determination of whether a field ditch or a canal should have a buffer for waste application.

• Typical field ditches that are above a junction with another ditch (first order) would almost always not require a buffer under 2H .0200. (Hoe drains are not considered a ditch.). Once the site inspection by the technical specialist verifies that the blue line is a first order field ditch, no other evaluation is necessary. Documentation of the field visit shall be included in the CAWMP.
• In cases where a ditch is below a junction with another ditch (2nd order or greater) then the technical specialist is responsible for a more extensive evaluation. Factors related to perennial stream flow are
  1. occurrence of flow during extreme drought (not dry on an annual basis),
  2. drainage area greater than 2 square miles in the coastal plain (excluding sandhills), and
  3. evidence or knowledge of the previous existence of a natural channel.
     
• A technical specialist shall visit a site and actually evaluate a field ditch or a canal before making the buffer determination. The technical specialist shall use the most recent edition of the USGS map(s) to make the required determination. The edition of the map(s) used must be documented.

9.2 How are Distances Measured from Perennial Streams?

Distances from perennial streams should be measured from the top of the stream bank in a horizontal line.

9.3 Setbacks from Perennial Streams

If a wet waste system is used, a setback is required for waste application from perennial waters as indicated on the most recent published version of USGS 7.5-minute topographic maps and other waters as determined by the local district (Appendix 8.1).

New and expanded animal waste storage and treatment facilities, such as but not limited to lagoons and ponds, must be located at least 100 feet from perennial waters unless it can be documented that no practicable alternative exists and that equivalent controls are used as approved by the SWCC.

9.4 Required Vegetation in Setbacks from Perennial Waters

Under SB 1217, the setback area next to perennial waters shall be a riparian buffer. A riparian buffer is defined by SWCC as a buffer that meets the NRCS Filter Strip Standard (Code 393). Among other things, this Standard requires that vegetation in the filter strip (buffer) consist of grass, trees or other "permanent" vegetation.

The first 25 feet next to the perennial waters shall be established as a riparian buffer as described above. The additional setback where required does not have to be in permanent vegetation and may be in crop production.

Filter strip requirements apply to animal waste applied adjacent to perennial waters. Although, there is no specific definition for adjacent in the NRCS Standards, if a producer maintains at least 100-foot setback from perennial waters, the wetted land application area can be considered as not adjacent. If the site has a considerable slope, the distance may need to be increased.

9.5 "Other Waters" Designated by Local SWCD

If a major ditch is constructed connecting two streams indicated as perennial waters (blue lines) on a USGS topographic map, the ditch can be designated as "other waters" by the local SWCD in accordance with 15A NCAC 2H .0217(a)(1)(B), (C)(ii) & (H)(vi). While the Rule is not specific as to what qualifies as "other waters", it appears that the intent of the Rule was to allow the SWCDs to designate streams, canals, etc. as "other waters" when they had the potential to adversely impact waters of the State. A SWCD may request assistance in making this determination from the SB 1217 Interagency Group.

9.6 Buffers for Non-Perennial Waters?

Filter strips or buffers are not required for non-perennial waters. However, the design of the waste application system shall preclude waste application in any stream, ditch or canal. Maintaining a sufficient distance between these and the irrigated site perimeter is required to prevent wind drift or runoff from entering waters. Other state or local regulations may supercede the above.