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<br />Often individuals or groups do not take mitigative
<br />actions because they do not understand what to do, or
<br />lack information and training on how to do it. Therefore,
<br />once landslide hazard information has been gathered, it
<br />must be communicated to planners, decision-makers,
<br />emergency response personnel, and the public. Maps
<br />are one of the best methods of information transfer
<br />available. The three most commonly used types of maps
<br />are: landslide inventories, landslide-susceptibility maps,
<br />and landslide hazard maps, A wide variety of maps has
<br />been prepared for Colorado.
<br />
<br />Chapter 5
<br />MITIGATION CONCEPTS
<br />AND APPROACHES
<br />
<br />The main goals of landslide hazard mitigation are to
<br />preserve lives, property, and revenue and to prevent the
<br />disruption of critical services and the economy. The
<br />three general methods of landslide hazard mitigation are
<br />1) modifying community vuineIability, 2) modifying
<br />pbysical systems, and 3) modifying the consequences of
<br />landsliding.
<br />Modifying community vulnerability involves such
<br />techniques as avoidance, building and grading codes,
<br />land-use regulations and policies, redevelopment restric-
<br />tions, hazard monitoring and warning systems. and
<br />emeIgency response and disaster preparedness.
<br />Pbysical modification is undertaken where human
<br />occupation of an unstable area already poses a risk, but
<br />where measures such as zoning and other land-use
<br />regulations are prec1uded by cost of resettlement,
<br />scarcity of land. or historical rights. Physical measures
<br />can be directed toward either control and stabi1ization,
<br />or protective functions. Physical mitigation methods
<br />used are categorized according to three types of land-
<br />slide movement, They address 1) slides and slumps,
<br />2) debris flows and debris avalanches, and 3) rockfall,
<br />These methods emphasize surface and subsurface
<br />drainage, slope stabi1ization measures such as the con-
<br />struction of buttresses and retaining structures. vegeta-
<br />, tion and soil hardening measures, and controlling the
<br />ways that land is cut, filled, and graded during
<br />development.
<br />Modifying the consequences of Iandsliding consists of
<br />methods designed to assist individuals and communities
<br />to prepare for, survive, and recover from hazard occur-
<br />rences. Such methods include increasing public
<br />awareness and the redistribution of losses by means of
<br />insurance,
<br />When development of potentially hazardous land is
<br />proposed, a cost-benefit analysis should be perform~
<br />to determine if mitigation is justifiable and cost effective.
<br />Frequently the costs may outweigh the benefits over the
<br />long tenn,
<br />
<br />2
<br />
<br />Chapter 6
<br />TH COLORADO lANDSLIDE
<br />PROBLEM
<br />
<br />erability (exposure) to the landslide
<br />related to the location of population
<br />use, emergency preparedness, and efforts
<br />tive action.
<br />In order design a statewide landslide hazard mitiga-
<br />tion plan. sleet priority projects, and determine unmet
<br />local needs, 49 communities and areas at risk were
<br />identified in Colorado. Three of these sites provide case
<br />studies be use they demonstrate 1) the types of land-
<br />slide that affect Colorado. 2) various levels of
<br />governmen involvement, 3) a variety of potential
<br />mitigative a 'ons, and 4) comparability to cases in other
<br />states. The three case studies have been analyzed to
<br />determine et local needs-those landslide problems
<br />which are t adequately addressed by the existing
<br />mitigation tem,
<br />
<br />
<br />
<br />Chapter 7
<br />E EXISTING APPROACH
<br />ITIGATION OF lANDSLIDE
<br />AZARDS IN COLORADO
<br />
<br />The legal b is authorizing state and local governments
<br />to manage dslide hazards in Colorado consists of a
<br />range of s tes, executive orders, and interagency
<br />memoran of understanding, Although none address
<br />Iandsliding usively, those which promote landslide
<br />manageme t activities under provisions addressing
<br />geologic ( d associated) hazards and emergency
<br />preparedn s are the most important,
<br />Coping 'th Iandsliding in Colorado involves the
<br />cooperatio of many public and private institutions and
<br />an levels 0 government. Local governments should take
<br />a lead role identifying goa1s and objectives, controll-
<br />ing land u ,providing hazard information and technical
<br />assistance, and implementing other strategies as
<br />descnbed' this plan. Although state and federal agen-
<br />cies play s ppilrting roles-primarily financial, technical,
<br />and admini tive-their efforts in supporting and coor-
<br />dinating mi' tion actions are particularly important.
<br />The nee to develop organizational systems at the
<br />state and I levels to deal with landslide mitigation
<br />over the 10 term in a coordinated and systematic man-
<br />ner is cl Local preparedness efforts should aim at
<br />the develo ment of landslide annexes to the Local
<br />Emergen Operations Plan (LEOP). Such an annex can
<br />provide fo timely and effective disaster response and
<br />recovery a 'ons by landslide-impacted jurisdictions, A
<br />model em ency response annex to the Garfield Coun-
<br />ty Emerge cy Operations Plan is presented in chapter 7
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