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Perennial streams are those that have a well defined channel and maintain flow or continuous pools of water throughout most of the year under typical climatic conditions. This includes natural streams that have been altered by dredging and/or straightening (see Canal Section). For perennial streams, the overall Special Management Zone is composed of a Primary Zone and, depending on the SSC, possibly a Secondary Zone. The Primary Zone for perennial streams ranges in width from 35 to 200 feet, depending on stream width or type, as shown in Table 1. Primary Zone widths in Table 1 are given for one side of the stream only. However, the Zone is applied to both sides of the stream. In addition, where the stream is connected to the inflow and/or discharge point of a flowing wetland, the Zone extends an additional 50 feet beyond the defined channel into the wetland(Figure 4). The Primary Zone is measured from the stream, beginning at the break in slope at the top of the stream bank, out to the designated width. Stream width is the typical bank to bank width of the stream within the harvest unit, measured in feet.
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| Table 1 : Primary Zone • Management Criteria |
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Stream Width/Type
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Primary Zone
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<20'
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35' per side
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20-40'
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75' per side
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> 40
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200' per side
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OFW
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200' per side
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Class I
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200' per side
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ONRW
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200' per side
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Selective timber harvesting is allowed within the Primary SMZ, consistent with the Primary Zone -Management Criteria. Clearcut harvesting is prohibited in the Primary SMZ, unless the operation qualifies as an exception as described in Appendix 11.
Depending on the SSC of the harvest unit, a Secondary Zone may also be required. If so, the Secondary Zone width is measured beginning at the outer boundary of the Primary Zone and continuing landward for the required distance as determined by the SSC (Appendix 1). Figure 1 shows examples of Primary and Secondary Zones on several different perennial streams, each with a different SSC. Note that where there is no Secondary Zone required, the Primary Zone is the total SMZ. Likewise, where the SSC is such that a Secondary Zone is required, the total SMZ width is the sum of the Primary Zone and Secondary Zone, up to a maximum of 300 feet. |
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