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<br />Table 3. Best Manage.~ent Practicea !~r sou\'J.':!n'Calllor~i~ me,M~as::.,Ji~';
<br />
<br />. 5Ml Seed Mixture 5Bll Sediment Basjn
<br />5F2 Silt Fence C012 Check Dams
<br />GB3 Rock,Wled Burlap Bags TA13 Trash Racks
<br /> 5B4 Straw Bales SR14 Slorm Drain Repair
<br /> OMS O'Y Straw Mulching eMIS Channel RepairlMocMication
<br /> 556 Hydraulic Soil Sealing 5016 Sand Bagging
<br /> BM7 Bonded FOOt Malrix EYI7 Evacualions
<br />I EBB ErosK>n Control Blanket WRI8 Warnings
<br />KR9 Concrele Tratlie Barriers EMI9 Emergency Crew Mobil;zahon
<br />RF10 Rocklall Nelhng llS20 Retaining Structure Repair
<br />I
<br />
<br />. Risk/liability
<br />. Aesthetics
<br />. $ujrabiliry for site
<br />. Feasibility
<br />. Durability or longevity
<br />
<br />No numerical equation presendy exists where-
<br />by an emergency mirigarion planner can establish
<br />me most appropriate solution to a post-fire prob.-
<br />lem. In almoSt all cases, successful erosion and
<br />sediment control involves a variety of techniques
<br />and materials which are pulled rogether ro form a
<br />compl~mcntary and composite system of BMPs.
<br />Above all, post-fire hazard mitiguion must
<br />bedone quickly... and be effecrive.
<br />Table 3 presents a lisring of .he BMP's select.
<br />c:d for implementation in the urban-interface
<br />areas of Laguna Beach, Orange County, Malibu
<br />and Thousand Oaks. NO! all of rhese BM Ps
<br />were used on sites. and in some areas. specific
<br />practices were relied on more than mhers. With
<br />all revegerarion BMPs, (SM I, OMS. 556,
<br />BM7, EB8) .he seed mixrures were specified by
<br />the Soil Conservation Service (SCS) as part of
<br />their technical assistance provided [0 affected
<br />communities through the Emergency Water-
<br />shed Program. These seed mixtures were com-
<br />posed primarily of native plam materials select-
<br />ed to complement indigenous plant
<br />re.establishmenl (Figure S). SCS field engineers
<br />also worked wiclt comracmcs hired by the com-
<br />munities, assisting in the coordination of work
<br />activities and inspccdng applications.
<br />It is imponam to note that neicher fe-estab-
<br />lishmem of native plant materials (from rom or
<br />seed which survived the fire) nor introduced
<br />vegetation (through hydraulic or broadcast
<br />seeding) provides enough soil protection in the
<br />first year following a fire to prevent erosion. For
<br />this reason, a cwo-pronged strategy was em-
<br />ployed which included: firsr, sedimenr conrrol,
<br />detention and diversion; and second, temporary
<br />cover practices which hold the soil in place until
<br />vegetarion is established,
<br />The sedimenr conrrol pracrices (SF2, GB3,
<br />SB4, KR9. SBl1, COl2, TRI3. and 5016)
<br />. were used in the immediate response to reduce
<br />the down-slope impac. of sedimenr (Figure 6)
<br />until soil stabilization measures could be im-
<br />plemenred.
<br />
<br />.
<br />
<br />The aggressive, source control practices
<br />(OMS. 556, BM?, and EB8) provided an im-
<br />mediate, temporary cover (Figure 7) that re-
<br />duced the erodibility of soils until permanent,
<br />soil-stabili:ting vegetation was re-established,
<br />Although all of these revegetation practices
<br />were used on the fire.affected areas to some de-
<br />gree, primary emphasis was placed on the use of
<br />hydraulic practices due to COst, timeliness,
<br />topographic, environmental compatibility, and
<br />safety concerns (Figure 8).
<br />
<br />Conclusion
<br />
<br />I< should be recognized that of rhe 186,000
<br />acres affected by .he fires of 1993, less than I
<br />percent of the area (<l ,800 acres) received the
<br />comprehensive erosion and sediment control
<br />treatments described in this paper. These were
<br />the urban and urban-wildland interface areas of
<br />highest priority identified in the Hazard Assess.
<br />rnent provided to the California Office of
<br />Emergency Services. Orange County, Laguna
<br />Beach, Thousand Oaks. and .he Big Rock area
<br />of Malibu received individua.l plans prepared
<br />for each community by Woodward-Clyde, and
<br />to a large degree, when implemented, these
<br />plans were effective in mitigating the erosion
<br />and sedimentation impacts from wimer storms.
<br />Much needs to be learned about post.fjre
<br />emergency erosion and sediment control in the
<br />urban interface and not JUSt from a technical
<br />standpoint about which practices should be
<br />used to mitiga.te impacts. We should accept the
<br />fact that the cycle of wildfires and the resulting
<br />erosion and sedimentation is a na.tural phenom-
<br />ena in Southern California and other western
<br />states as well. But to the people who are affect-
<br />ed by these processes, those: living at the utban-
<br />wildland interface, questions on whether or not
<br />to use any mitigation practices at all are moot:
<br />Do-nothing alternatives are: not politically,
<br />technic.ally, economic.ally. or socially accep..ble.
<br />People and their activities are as much a parr of
<br />the post-fire environment as are: native planes
<br />and animals, and any approach that does not
<br />incorporate human resources and values as parr
<br />of a mitigation strategy fails to appreciate the
<br />practical interface between humans and their
<br />environment. B
<br />
<br />Carol L, Forrm,
<br />P.E,C.P.ES.C. is a
<br />Pn'ncipal at Woodward-
<br />Clyde Cons.ltanu
<br />San DieKo. WI 92108;
<br />Micha~l V. Harding.
<br />C.P.ES.C.. is a r"hnical
<br />Snviur Manag~r,
<br />Enginurrd Fibrr ProdIKts,
<br />WtytTha~tT Company.
<br />San DieKo. WI 92106.
<br />
<br />
<br />NOVEMBER.DECE.MBER 1994 541
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