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between "good" and "fair" effectiveness. Like loggrade stabilizers, this technique is expeneive and time con- suming. Akey implementation factor is the availabil- ity ofrock for the grade stabilizers. A couple of impor- tant implementation factors that affect effectiveness are: (1) the use of rocks that are large enough to resist transport during runoff events, and (2) placement of organic debris or sediment screening on the upstream aide of the grade stabilizer. Channel Debris Clearine Purpose. Channel clearing is the removal or size re- duction ofloge and other organic debris or the removal of sediment deposits to prevent them from being mo- bilized in debris flows or flood events or altering stream geomorphology and hydrology. This treatment has been done to prevent creation of channel debris dame which might result in flash floods, or aggravate flood heights or peakflows. Organic debris can lead to culvert failure by blocking inlets culverts, or reduce channel flow capacity. Excessive sediments in stream channels can compromise in-channel storage capacity and the function of debris basins. Relatrve Effectrveness Excellent-0% Gaod-71% Fair- 0% Poor-29% (Replies = 7) Channel debris clearing was rated as "good" in effec- tiveness bythemajority ofthe intervieweea,but nearly a third rated its effectiveness to be "poor." The latter rating came from aituatione where there was not enough post-fire organic debris in riparian areas or the channels to cause debris dam problems or stream hydrology was adversely altered by clearing. Because much ofthe debriefromfire-killed trees does not enter channel system until 2 or 3 years later, this treatment was not considered by some to be a useful BAER treatment. Also, there has been a significant improve- ment inthe understanding of the positive role of large woody debris in trapping sediment, dissipating the energy of flowing water, and providing aquatic organ- ism habitat. In some instances the channel clearing hoe been more disruptive than the wildfire. So, in some areas the policy now is to avoid channel clearing. Channel clearing is definitely an expeneive, time- eonauming operation, but it has been successful in certain aituatione ouch as locations where trash racks cannot be used to protect road culverts, where woody debris might move into reservoirs, and where sedi- ment must be removed from debris basins and chan- nels to provide adequate sediment storage capacity. Important factors in the relative effectiveness of channel clearing, when it is used, include a good analysis of risk and the value of resources at risk, knowledge of the size and quantity of material to remove, the clearing distances above roads needed to protect culverts, and understanding of the physical characteristics of the channels which might aggra- vate or reduce atormflowa. Implementation and Environmental Factors Timing is an important factor which affects both the effective- ness and the assessment of the value of channel clearing. When sediment removal is the objective of channel clearing, operations must be done before sea- sons (usually winter) that produce the first or most significant stormflows. For large woody debris, the key question is if and when inputs of woody debris are likely to occur. In some areas, woody debris recruit- ment (greater than 2 years) may be beyond the timeframe of BAER projects. Crewe conducting chan- nel clearing must be well trained in order to recognize woody material that is too large to float or be firmly anchored, is part of the natural inatream coarse woody debris load, or is a natural grade stabilizer. Where woody debris ie cut up it must be sufficiently short to pass through culverts. Other Factors Channel debris clearing may produce significant, adverse riparian area impacts, destabi- lize the channel, reduce aquatic habitat, and alter stream hydrology. These aide effects may negate any positive benefits derived from channel clearing in some aituatione. Stream Bank Armoring/Channel Armoring Purpose: Stream bank and channel armoring is done to prevent erosion of channel banks and bottoms during runoff events. In some hydrologic systems stream banks are a major source of sediment. Relatrve Effectrveness Not enough interviewees rated this treatment. Comments on armoring indicated that it functions well in small, ephemeral drainages or near the heads of larger ephemeral drainages, and lower gradient areas. In steep terrain, sloughing ofupslope materials can bury the bank armoring. Implementation and Environmental Factors Stream bank armoring requires proper design, swell-devel- opedimplementation plan, and experienced crews for maximum effectiveness. Othor implementation fac- tors that contribute to success include proper sized materials, use of geotextfle fabric, avoiding overly steep areas, and the use of energy disaipatora. In-Channel Felling Purpose. This BAER channel treatment is designed to replace woody material in drainage bottoms that have been consumed by wildfire. It is intended to trap organic debris and temporarily detain or slow down storm runoff. Woody material felled into channels will ultimately alter channel gradient, and may cause sediment deposition and channel aggradation. USDA Forest Service Gen. Tech. Rep. RMRS-GTR-63.2000 81