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Best Management Practices for
Braided Stream Systems:
A Supplement to the 1994 BMP Manual

The bottomland hardwood stands in the Coastal Plain of South Carolina have experienced harvesting once or more since the European colonization of the state. With the introduction of steam locomotives and rehaul skidding in the early 1900's, intensive harvesting occurred throughout much of the coastal plain bottomland forests. The stands regenerated after these harvesting operations are again reaching commercial maturity. Because large areas are being harvested in a relatively short time span, public awareness of bottomland forestry activities has been heightened.

Braided Streams' Multiple channels
Figure 1. Braided streams have multiple channels that interconnect like the strands of a braid.

Braided stream systems have multiple interconnected channels,(Figure 1), resembling the strands of a braid, with very low stream gradient (<0.5% channel slope). These systems generally have broad valleys with well-defined floodplains. High water tables for much of the year result in soils with high organic content. Overland flows generally occur during the winter and spring. These characteristics create unique conditions for harvesting operations; therefore, additional BMPs are necessary.

Most braided streams are located in jurisdictional wetlands (as defined by the federal Clean Water Act) and some portions of these systems are considered navigable by the Department of Health and Environmental Control (DHEC) or the U.S. Army Corps of Engineers (COE). A permit is required to cross any navigable stream, and landowners and forestry operators should carefully evaluate their proposed forest management activities in these systems to determine if a consultation with DHEC or the COE is required. South Carolina Forestry Commission foresters are available to assist landowners and forestry operators to determine if a consultation is necessary.

Table 1: Representative segments of braided and non-braided streams.

County Water Body Location Braided (Yes/No)
Colleton Little Salkehatchie River Between Highway 64
and Highway 63
Yes
Colleton and Hampton Salkehatchie River From the junction with the the Little Salkehatchie River northwest for 2 miles. Yes
Dorchester Four Hole Swamp Between Highway 15 and Highway 453 No
Williamsburg Santee Swamp Between Suttons and Gourdin No

South Carolina's Best Management Practices for Forestry, published in 1994, do not specifically address some important considerations for protecting braided streams. The following supplemental BMPs for braided stream systems provide additional protection for their chemical, physical, and biological attributes. These BMPs also address navigation, and impacts from harvesting operations should be minimized if all BMPs are followed.

Streamside Management Zones For Braided Streams

Braided stream channels or runs should be identified before harvesting in order to prescribe adequate streamside protection. Protection needs vary depending on the size of the run.

The SMZ on major runs is divided into two parts: the primary and the secondary. The primary SMZ is 40-feet wide on each side of the stream. The width of the secondary SMZ is an additional 40-feet on each side of the stream adjacent to the primary SMZ. On minor runs, there is a 40-foot primary SMZ. When operating in braided stream systems, forest management activities within the primary and secondary SMZs should be carried out following the recommendations listed below.

Maximum stream depthCross section locations
Figure 2. (A) Bankfull discharge is determined using maximum stream depth, measured from the level where the stream just fills the channel to the bottom of the channel. Stream segments that average 3 feet or more at bankfull depth are major runs and require a primary and secondary SMZ. (B) Recommended cross-section locations for bankfull stage measurements.

BMPs

AVOID

Road Stream Crossings

Braided stream systems often require additional stream crossings for access, depending on the number of major and minor runs. Major runs are generally considered to be navigable, therefore anyone considering crossing a major run with a road should contact DHEC (843-448-1902) for guidance.

BMPs

AVOID

Table 2.Recommended Diameters & Spacing for Culverted Crossing on Minor Runs. (For example, a 2-foot deep channel that is 12-feet wide would require three 24-inch culverts)

Depth of
Channel (feet)
Pipe Size
(inches)
Channel Width
per Pipe (feet)
< 2 24 7
2-3 24 4
2-3 30 6

Culvert Installation
Figure 3. Culvert Installation. The culvert should be placed at the grade of the stream channel . Hardened road dips should be constructed on each side of the culvert to handle overflow. If flexible PVC pipe is used, extra care should be taken to ensure that it is installed properly.

Forest Road Construction

Forest road construction in braided stream systems is subject to state and federal wetland/water quality regulations. Road construction for silvicultural purposes in jurisdictional wetlands does no require a permit because of the silvicultural exemtion under Section 404 of the Clean Water Act. However, to qualif for the silvicultural exemption, the road construction must comply with the federally-mandated BMPs listed in the BMP Manual. The silvicultural exemption from permitting only applies to roads built specifically for forest management purposes. Roads built primarily for non-silvicultural activities, such as for access to a house or hunting camp, require a permit from the U.S. Army Corps of Engineers. The following BMPs are listed for additional interpretation of subjective areas covered by the 15 federally-mandated BMPs.

BMPs

AVOID

Timber Harvesting

The planning phase of a timber harvesting operation in a braided stream system is especially important due to seasonal access problems during flooded conditions. The location and construction of roads, stream crossings, streamside management zones, and log decks are best performed under non-flooded conditions. The harvesting operation should utilize appropriate equipment and techniques to minimize both on-site and off-site impacts. Plan and execute timber harvests under the supervision of a liscensed forester.

BMPs

AVOID

Additional Management Considerations

When planning and conducting a harvesting operation in braided stream systems, some additional factors may need to be considered. Although not considered BMPs, suggestions from the following list may be incorporated into sales contracts or harvesting plans where appropriate:


Forest Management/ Reference Resources / Environmental Forestry/ Braided Stream Systems /Best Management Practices