Chapter 4 Hazard Identification, Assessment, and Mapping Hazard Analysis activities as well as much geologic information. In addition, the availability of many types of Recognition of the presence of active or poten- aerial imagery (satellite, infrared, radar, etc.) tial slope movement, and of the types and make this a very versatile technique. causes of the movement, is essential to land- slide mitigation. Recognition depends on an Analysis of Acoustic Imagery accurate evaluation of the geology, hydrogeol- and Profiles* ogy, landforms, and interrelated factors such as Profiles of lake beds, river bottoms, and the sea environmental conditions and human activi- floor can be obtained using acoustic techniques ties. Only trained professionals should conduct such as side-scan sonar and subbottom seismic such evaluations. However, because local gov- profiling. Surveying of controlled grids, with ernments may need to contract for such ser- accurate navigation, can yield three-dimension- vices, they should be aware of the techniques al perspectives of subaqueous geologic phenom- available and their advantages and limitations. ena. Modern, high resolution techniques are Techniques for recognizing the presence or used routinely in offshore shelf areas to map potential development of landslides include: geologic hazards for offshore engineering. * map analysis Surveying and mapping standards for outer * analysis of aerial photography and continental shelf regions are regulated by the imagery U.S. Minerals Management Service. * analysis of acoustic imagery and profiles * field reconnaissance Field Reconnaissance * aerial reconnaissance Many of the more subtle signs of slope move- * drilling ment cannot be identified on maps or photo- * acoustic imaging and profiling graphs. Indeed, if an area is heavily forested or * geophysical studies has been urbanized, even major features may * computerized landslide terrain analysis not be evident. Furthermore, landslide features * instrumentation change over time on an active slide. Thus, field reconnaissance is necessary to verify or detect Map Analysis many landslide features. Map analysis is usually one of the first steps in a landslide investigation. Maps that can be Aerial Reconnaissance used include geologic, topographic, soils, and Low-level flights in helicopters or small air- geomorphic. Using knowledge of geologic mat- craft can be used to obtain a rapid and direct erials and processes, a trained person can ob- overview of a site. tain a general idea of landslide susceptibility from such maps. Drilling At most sites, drilling is necessary to determine Analysis of Aerial Photography the type of earth materials involved in the slide, and Imagery the depth to the slip surface and thus the thick- The analysis of aerial photography is a quick ness and geometry of the landslide mass, the and valuable technique for identifying land- water-table level, and the degree of disruption slides, because it provides a three-dimensional *By D.B. Prior overview of the terrain and indicates human 20 of the landslide materials. It can also provide Anticipating the Landslide samples for age-dating and testing the engin- Hazard eering properties of landslide materials. Fin- One of the guiding principles of geology is that ally, drilling is needed for installation of some the past is the key to the future. In evaluating monitoring instruments and hydrologic obser- landslide hazards this means that future slope vation wells. failures will probably occur as a result of the Geophysical Studies same geologic, geomorphic, and hydrologic situations that led to past and present failures. Geophysical techniques (the study of changes Based on this assumption, it is possible to in the earth's gravitational and electrical estimate the types, frequency of occurrence, fields, or measurement of induced seismic be- extent, and consequences of slope failures that havior) can be used to determine some subsur- may occur in the future. However, the absence face characteristics such as the depth to bed- of past events in a specific area does not pre- rock, zones of saturation, and sometimes the clude future failures. Man-induced conditions ground-water table. It can also be used to de- such as changes in the natural topography or termine the degree of consolidation of subsur- hydrologic conditions can create or increase an face materials and the geometry of the units area's susceptibility to slope failure (Varnes involved. In most instances these methods can and the International Association of Engin- best be used to supplement drilling informa- eering Geology, 1984). tion. Monitoring of natural acoustic emissions In order to predict landslide hazards in an from moving soil or rock has also been used in area, the conditions and processes that pro- landslide studies. mote instability must be identified and their Computerized Landslide Terrain relative contributions to slope failure estimat- Analysis ed, if possible. Useful conclusions concerning increased probability of landsliding can be In recent years computer modeling of land- drawn by combining geological analyses with slides has been used to determine the volume knowledge of short- and long-term meteor- of landslide masses and changes in surface ological conditions. Current technology enables expression and cross section over time. This persons monitoring earth movements to define information is useful in calculating the poten- those areas most susceptible to liandsliding and tial for stream blockage, cost of landslide to issue "alerts" covering time spans of hours to removal (based on volume), and type and mech- days when meteorological conditions known to anism of movement. Very promising methods increase or initiate certain types of landslides are being developed utilizing digital elevation occur. Alerts covering longer periods of time models (DEMs) to evaluate areas quickly for become proportionately less reliable. their susceptibility to landslide/debris-flow events (Filson, 1987; Ellen and Mark, 1988). Translation of Technical Computers are also being used to perform complex stability analyses. Software programs Information to Users for these studies are readily available for per- According to Kockelman (personal comnmunica- sonal computers. tion, 1989), the successful translation of nat- ural hazard information for nontechnical users Instrumentation conveys the following three elements in one Sophisticated methods such as electronic form or another: distance measuring (EDM); instruments such (1) likelihood of the occurrence of an event as inclinometers, extensometers, strain meters, of a size and location that would cause tiltmeters, and piezometers; and simple tech- casualties, damage, or disruption; niques such as establishing control points (2) location and extent of the efflects of the using stakes can all be used to determine the event on the ground, structures, or mechanics of landslide movement and to warn socioeconomic activity; against impending slope failure. 21 geologic units or environments in which addi- (3) estimated severity of the effects on the ground, structures, or socioeconomic tional movements are most likely. Such map- ping relies heavily on photogeology (the geolog- activity. These elements are needed because usu- ic interpretation of aerial photography), ally engineers, planners, and decision makers reconnaissance field mapping, and the collec- will not be concerned with a potential hazard if tion and synthesis of all available pertinent its likelihood is rare, its location is unknown, geologic data (Leighton, 1976). or its severity is slight. Regional maps are most often prepared at Unfortunately, these three pieces of infor- a scale of 1:24,000, because high-quality U.S. mation can come in different forms with many Geological Survey topographic base maps at this scale are widely available, and aerial different names, some quantitative and pre- cise, others qualitative and general. For a pro- photos are commonly of a comparable scale. duct to qualify as "translated" hazard inform- Other scales commonly used include 1:50,000 ation, the nontechnical user must be able to (county series), 1:100,000 (30 x 60 minute perceive likelihood, location, and severity of the series), and 1:250,000 (1 x 2 degree series). hazard so that he or she becomes aware of the Community-Level Mapping danger, can convey the risk to others, and can use the translated information directly in a Community-level mapping identifies both the reduction technique. three-dimensional limits of landslides and Maps are a useful and convenient tool for their causes. Guidance concerning land use, presenting information on landslide hazards. zoning, and building, as well as recommenda- They can present many kinds and combina- tions for future site-specific investigations, are tions of information at different levels of detail. also made at this stage. Investigations should Hazard maps used in conjunction with include subsurface exploratory work in order to land-use maps are a valuable planning tool. produce a large-scale map with cross sections Leighton (1976) suggests a three-stage appro- (Leighton, 1976). Map scales at this level vary ach to landslide hazard mapping. The first from 1:1,000 to 1:10,000. stage is regional or reconnaissance mapping, Site-Specific Mapping which synthesizes available data and identifies general problem areas. This small-scale map- Site-specific mapping is concerned with the ping is usually performed by a state or federal identification, analysis, and solution of actual geological survey. The next stage is commun- site-specific problems. It is usually undertaken ity-level mapping, a more detailed surface and by private consultants for landowners who subsurface mapping program in complex pro- propose site development and typically involves blem areas. Finally, detailed site-specific a detailed drilling program with downhole logging, sampling, and laboratory analysis in large-scale maps are prepared. If resources are order to procure the necessary information for limited, it may be more prudent to bypass re- gional mapping and concentrate on a few design and construction (Leighton, 1976). Map known areas of concern. scales vary, but are usually not larger than one inch equal to 50 feet. Regional Mapping Types of Maps Regional or reconnaissance mapping supplies The three types of landslide maps most useful basic data for regional planning, for conducting more detailed studies at the community and to planners and the general public are (1) landslide inventories, (2) landslide suscepti- site-specific levels, and for setting priorities for bility maps, and (3) landslide hazard maps. future mapping. These maps are usually simple inventory Landslide inventories maps and are directed primarily toward the Inventories identify areas that appear to have identification and delineation of regional land- failed by landslide processes, including debris slide problem areas and the conditions under flows and cut-and-fill failures. The level of which they occur. They concentrate on those 22 with selective field checking to detect landslide detail of these maps ranges from simple recon- areas, and then presenting the information in naissance inventories that only delineate broad map form using a coded format. The maps areas where landsliding appears to have show any or all of the following: state of activi- occurred (Figure 20) to complex inventories ty, certainty of identification, dominant types of that depict and classify each landslide and slope movement, estimated thickness of slide show scarps, zones of depletion and accumu- material, and dates or periods of activity. lation, active versus inactive slides, geological age, rate of movement, and other pertinent Landslide susceptibility maps data on depth and kind of materials involved in A landslide susceptibility map goes beyond an sliding (U.S. Geological Survey, 1982; Brabb, inventory map and depicts areas that have the 1984b) (Figure 21). potential for landsliding (Figure 22). These Simple inventories give an overview of the areas are determined by correlating some of landslide hazard in an area and delineate the principal factors that contribute to land- areas where more detailed studies should be sliding, such as steep slopes, weak geologic conducted. Detailed inventories provide a unIits that lose strength when saturated, and better understanding of the different landslide poorly drained rock or soil, with the past dis- processes operating in an area and can be used tribution of landslides. These maps indicate to regulate or prevent development in landslide only the relative stability of slopes; they do not areas and to aid the design of remedial meas- make absolute predictions (Brabb, 1984b). ures (U.S. Geological Survey, 1982). They also Landslide susceptibility maps can be provide a good basis for the preparation of considered derivatives of landslide inventory derivative maps such as those indicating slope maps because an inventory is essential for pre- stability, landslide hazard, and land use. Wiec- paring a susceptibility map. Overlaying a geo- zorek (1984) described how to prepare a land- logic map with an inventory map that shows slide inventory map that can be used by plan- existing landslides can identify specific land- ners and decision makers to assess landslide slide-prone geologic units. This information can hazards on a regional or community level. The then be extrapolated to predict other areas of process consists of using aerial photography EXPLANATION Areas inf erred to be underlain by landslide deposits I r 1:250,000 ~~TOScale U) T ~ ' ~~ _ _WT A Figure20. Detail from the landslide inventory map of the Durango 1 x 2 degree map, Colorado (Colton et ad, 1975). 23 Detail from map showingrecently ( and dormant ~~~~~~~~~~~~~~active landslidesnear La Honda, central Santa Cruz Mountains, California. Informa- tion shown on this O0 - map includes: state NK of activity,dominant ~~~~' of slope move- ... ~~~~~~~~~~~~~~~type ) ~~~~~~~ment, direction of 000 movement, scarp ~9504 1 ~~~~~~~~~~location,depth and date of movement. See map for detailed explanation. / ~~(Wieczorek, 1982.) k ~~~~~~~~~~EXPLANATION 606 Stable slopes ~~i~ x ~ Liii ~Normally stable I slopes JEUnstable slopes Old landslide ~~~~~~~~~~~~~~~~~deposits 0 Scale 1:24,000 Figure 22. Detail from map showing relative slope stabilityin part of west-central King County, Washington (Miller, 1973). 24 now, and the likelihood in various areas that a potential landsliding. More complex maps may landslide will occur in the future (Figure 23). include additional information such as slope, For a given area, they contain detailed inform- angle, and drainage. ation on the types of landslides, extent of slope Landslide hazard maps subject to failure, and probable maximum ex- Hazard maps show the areal extent of threat- tent of ground movement. These maps can be ening processes: where landslide processes used to predict the relative degree of hazard in have occurred in the past, where they occur a landslide area. EXPLANATION Susceptibility of area U- likely to fail 1r | -E High M Mod(3rate Low ~ = Very low LUquE)factio n m N Scale 1:62,50 Figure23. Detail from map showing slope stability during earthquakesin San Mateo County, California(Wieczorek at aL, 1985). 25 Transferring and Encouraging the Use of Information A major part of any effective landslide loss-re- hazard-related activities, (2) the existence of duction program must be the communication enabling legislation authorizing federal, state, and use of technical information (information and local hazard-reduction activities, (3) the transfer). Often individuals or groups do not availability of funds and adequate, sufficiently take mitigative action because they do not detailed information in a readily usable and understand what to do, or lack training on how understandable form, (4) the use of effective to do it. The mitigation and/or avoidance of information communication techniques, and (5) landslide hazards and the reduction of land- the existence of qualified staff at all levels of slide losses require that appropriate informa- government with the authority to take mitiga- tion be communicated to, and effectively used tive action. by, planners, decision makers, and emergency response personnel. Information Transfer According to Kockelman (personal com- Methods for transferring and/or obtaining munication, 1989), various terms are used to landslide information are listed in Table 3. describe the transfer of information to users, These methods should be used by any landslide namely "disseminate," "communicate," "circu- information collection, interpretation, and late," "promulgate," and "distribute." Often transferral program designed for planners and these terms are interpreted conservatively. For decision makers. Some of these services are example, an agency or person might simply provided by state agencies, map sales offices, issue a press release on hazards or distribute geologic inquiries staffs, public inquiries offi- research information to potential users. Such ces, universities, and, in the course of ordinary activity rarely results in the adoption of effec- day-to-day contacts with the public, by the tive hazard reduction techniques. producers of landslide hazard information. In Kockelman notes that no clear, concise de- addition, many research workers have provided finition or criteria for effective information such services on a limited and informal basis. transfer has been offered or can be found in the literature, except by inference or by analysis of Table 3. Examples of resources available for what actually works for lay persons. Therefore, obtaining/ transferringlandslide information he uses "transfer" to mean the delivery of an (adapted from U.S. GeologicalSurvey, 1982). understandable product in a usable format to a specific person or group "interested" in, or re- Educational Services sponsible for, hazard reduction, plus assistance * Universities and their extension divisions and encouragement in the selection and adop- through courses, lectures, books, and dis- tion of an appropriate reduction technique. play materials Only when all these criteria have been met * Guest speakers and participants at lectur- have researchers, translators, and transfer es in regional and community educational agents fulfilled their objectives. programs related to the application of The effective use of landslide information hazard information to reduce danger, damages, or other losses * Seminars, conferences, workshops, short depends not only on the efforts of the producers courses, technology utilization sessions, of the information, but also on (1) the users' training symposia, and other discussions interest, capabilities, and experience in involving user groups 26 Table 4. Potentialusers of landslide hazard Table 3. Continued information (modified from U.S. Geological Survey, 1982). Oral briefings, newsletters, seminars, * map-type "interpretive inventories," City, County, and Area-Wide open-file reports, reports of cooperating Government Users agencies, and "official-use only" materials (released via news media) City and county building, engineering, zoning, Radio and television programs that explain * safety, planning, and environmental or report hazard-reduction programs and health departments products City and county offices of emergency services Meetings with local, district, and state * County tax assessors agencies and their governing bodies Local government geologists Field trips to potentially hazardous sites * Mayors, county commissioners, and city council by state, local, or federal agencies, and members professional societies Multicounty (regional) planning, development, and emergency preparedness agencies Information Sources Municipal engineers, planners, and adminis- Annotated and indexed bibliographies of * trators hazard information and lists of pertinent Police, fire, and sheriffs departments reference materials Public works departments Local, state, and federal policies, procedur- * Road departments es, ordinances, statutes, and regulations School districts that cite or make other use of hazards Special districts (water, sanitation, urban information drainage) Hazards information incorporated into * local, state, and federal studies and plans State Government Users* User guides relating to earth-hazards * Attorney General's Office processes, mapping, and hazard-reduction Department of Administration techniques State Buildings Division Department of Health Department of Highways Department of Local Affairs Users of Landslide Hazard Information Department of Military Affairs Among the potential users of landslide hazard National Guard information are people at national, state, region- Department of Natural Resources al, and community levels in both the public and Geological Survey private sectors. Three general categories can be Water Conservation Board identified: (1) scientists and engineers who use Water Resources the information directly, (2) planners and deci- Department of Public Safety sion makers who consider hazards among other Emergency Management Agencies land-use and development criteria, (3) develop- Department of Revenue ers and builders; financial and insuring organi- State Planning and Budgeting Office zations, and (4) interested citizens, educators, and others with little or no technical expertise. *NOTE: Names and functions of state agencies These people differ widely in the kinds of infor- vary from state to state and this list should mation they need and in their capabilities be adapted accordingly. to use that information. Examples of potential users are listed in Table 4. 27 Table 4. Continued Other National Users Applied Technology Council Federal Government Users American Association of State Highway and Department of Agriculture Transportation Officials Farmers' Home Administration American Public Works Association Forest Service American Red Cross Soil Conservation Service Association of Engineering Geologists Department of the Army Association of State Geologists Army Corps of Engineers Council of State Governments Department of Commerce Earthquake Engineering Research Institute National Bureau of Standards International Conference of Building Officials National Oceanic and Atmospheric National Academy of Sciences Agency National Association of Counties Department of Housing and Urban National Association of Insurance Development Commissioners Federal Housing Administration National Governors' Association Department of the Interior National Institute of Building Sciences Bureau of Land Management Natural Hazards Research and Applications Bureau of Reclamation Information Center, University of Colorado Geological Survey National League of Cities National Park Service Professional and scientific societies (including Department of the Navy geologic, engineering, architecture, and Department of Transportation planning societies) Federal Highway Administration United States Conference of Mayors Environmental Protection Agency Federal Emergency Management Agency General Services Administration Most states have professional planners, Members of Congress and their staffs engineers, or geologists available who can Nuclear Regulatory Commission make interpretations from available hazard Small Business Administration information. Specialists from the federal gov- ernment who are skilled in the translation of Private, Corporate, and technical data can also assist states. As sug- Quasi-Public Users gested in Chapter 4, the most effective use of Civic and voluntary groups landslide information is achieved when maps Concerned citizens, homeowners associations are prepared that indicate the location, sever- Construction companies ity, and recurrence potential of landslides. Consulting planners, geologists, architects, and engineers Developing an Information Base: Economic development committees Sources of Landslide Hazard Extractive, manufacturing, and processing industries Information Financial and insuring institutions Some of the organizations that produce or Landowners, developers, and real estate agents provide landslide hazard information are listed News media in Table 5. Utility and transmission companies University departments (including geology, civil engineering, architecture, urban and regional planning, and environmental studies departments) 28 Table 5. Examples of producersand provid- Journalists, commentators, editors, and other ers of landslide hazard information (adapted news professionals from U.S. GeologicalSurvey, 1982). Local seismic safety advisory groups National Governors' Association Natural Hazards Research and Applications American Institute of Professional Geologists American Society of Civil Engineers Information Center. University of 'Colorado Public information offices (federal and state) Association of Engineering Geologists U.S. Army Corps of Engineers County extension agents U.S. Bureau of Land Management Educators (university, college, high school) U.S. Bureau of Reclamation Museum of Natural History U.S. Forest Service State Department of Highways State Geological Survey U.S. Geological Survey Hazard researchers, interpreters, and mappers U.S. Soil Conservation Service International Conference of Building Officials 29 Landslide Loss-Reduction Techniques is i; ;~~~~~~~~~~~~~~~~~~~~~~~~~~_ A significant reduction in landslide losses can short supply, there is strong motivation and be achieved by preventing or minimizing the pressure to use the land intensively. Land-use exposure of populations and facilities to land- regulations must be balanced against econ- sliding; by preventing, reducing, or managing omic considerations, political realities, and the actual occurrence of landslides; and by historical rights. physically controlling landslide-prone slopes Various types of land-use regulations and and protecting existing structures. development policies can be used to reduce Subsidized insurance is not considered a landslide hazards. Some of these methods are loss-reduction technique because it does not listed in Table 2, Chapter 2. Responsibility prevent or reduce losses but merely transfers for their implementation resides primarily the loss to other segments of the population. with local governments, with some involve- Indeed, it may encourage lenders to develop ment of state and federal governments and the hazardous lands because they are indemnified private sector. by uninvolved taxpayers. The insurance indus- try could become a strong promoter of hazards Reducing the Occurrence of reduction if it would establish its rates to re- Landslides and Managing flect relative risks. Most homeowners' insur- Landslide Events ance policies exclude coverage for ground movements, including landslides. As discussed in Chapter 3, many landslides occur as a direct result of human activities. Preventing or Minimizing The excavation and grading associated with the construction of buildings, highways, trans- Exposure to Landslides mission lines, and reservoirs can create Vulnerability to landslide hazards is a function conditions that will ultimately result in slope of a site's location, type of activity, and frequen- failure. The development and enforcement of cy of landslide events. Thus, the vulnerability codes for excavation, grading, and construction of human life, activity, and property to land- can prevent such landslides. A review of the sliding can be lowered by total avoidance of state of the art and standards of performance landslide hazard areas or by restricting, prohi- of hillside and flatland urban development biting, or imposing conditions on hazard-zone from the 1950s to the early 1980s is available activity. Local governments can accomplish this in a training manual (Scullin, 1982). This man- by adopting land-use regulations and policies ual describes the mitigation of several geologic and restricting redevelopment. hazards: landsliding, subsidence, expansive soils, drainage, and earthquakes. The concepts Land-Use Regulations and technical applications described in this Land-use regulations and policies are often the book may be applied in short-or long-term most economical and effective means of regula- planning regarding geologic risks anywhere. tion available to a community-particularly if enacted prior to development. However, where Building and Grading Codes potentially hazardous land is privately owned Design, building, and grading codes are with the expectation of relatively intense dev- regulatory tools available to local government elopment and use, or where land optimally agencies for achieving desired design and suited for development in communities is in building practices. They can be applied to both 30 new construction and pre-existing buildings. In slide-prone areas, with effective linkages to a -rare cases, such as those involving large off- central communication warning facility and, shore structures, the effect of landslides can be thence, to individuals with disaster manage- considered explicitly as part of the design, and ment responsibilities, are also sometimes used. the facility can be built to resist landslide dam- age. In some cases, existing structures in land- Warning systems can be long-term or tempor- slide-prone areas can be modified to be more ary-used only when high risk conditions exist accommodating to landslide movement. The ex- or while physical mitigation methods are being tent to which this is successfiul depends on the designed and built (Figure 25). type of landsliding to which the structure is exposed. Facilities other than buildings (e.g., gas pipelines and vater mains) can also be designed to tolerate ground movement. Codes i CLIMB and regulations governing grading and exca- vation can reduce the likelihood that construc- tion of buildings and highways will increase TO the degree to which a location is prone to landslides. Various codes that have been devel- oped for federal, state, and local implementa- SAFETY! tion can be used as models for landslide-dam- age mitigation. A fundamental concern with design and building codes is their enforcement m a uniform and equitable way. (Committee on Ground Failure Hazards, 1985, p. 15). IN CASE OF A Emergency Management FLASH FLOOD Emergency management and emergency plan- ning contribute to landslide loss reduction by saving lives and reducing injuries. Such plan- Figure24. Sign placed in some of the hazard- ning can also protect and preserve property in ous mountain canyon areas of Colorado. those cases where property is mobile or where protective structures can be installed if suffi- cient warning time is available. Controlling Landslide-Prone Emergency management and planning Slopes and Protecting consist of identifying potential hazards, deter- mining the required actions and parties respon- Existing Structures sible for implementing mitigation actions, and Physical reduction of the hazard posed by ensuring the readiness of necessary emergency unstable slopes can be undertaken in areas response personnel, equipment, supplies, and where human occupation already poses a risk, facilities. An important element of emergency but where measures such as zoning are pre- management is a program of public education cluded by the cost of resettlement, value or and awareness informing citizens of their po- scarcity of land, or historical rights. Physical tential exposure, installation of warning sys- measures can attempt to either control and tems, types of warnings to be issued, probable stabilize the hazard or to protect persons and evacuation routes and times available, and property at risk. appropriate protective actions to be taken. It is not possible, feasible, or -evennecessar- A warning system may include the moni- ily desirable to prevent all slope movements. toring of geologic and meteorologic conditions Furthermore, it may not be economically fea- (e.g., rates of landslide movement, snowmelt sible to undertake physical modifications in runoff, storm development) with potential for some landslide areas. Where land is scarce, causing a catastrophic event or the placement however, investment in mitigation may in- of signs instructing people within a potentially crease land value and make more expensive hazardous area of proper procedures (Figure and elaborate mitigation designs feasible. 24). Automatic sensors, located within land- 31 device Channel DESIGN IN Fi FINAL BY INSTALLERS < Parts List Strok Cabh Used Spea Solar Batte Regu Relal Cabli gate and v Powe (Donat Colora and Lii SubtE Conti Total $1351 Figure 25. Schematic of a warning system (by Robert Kistner, Kistner and Associates). Landslide control structures can be costly and usually require considerable lead time for project planning and design, land acquisition, permitting, and construction (Figure 26). Such structures may have significant environmental and socioeconomic impacts that should be con- sidered in planning. Precautions Concerning Reliance on Physical Methods Although physical techniques may be the only means for protecting existing land uses in haz- ard re. solt rlianep nnthem mqv reate a basini 1_ Figure RuddCreek debris 26. false sense of security. An event of greater sev- Farmington, constructed 19n 84 in Utah erity than that for which the project was de- Kistn.erand (photograph Robert Kistner, by signed may occur, or a structure may fail due to Associates). aging, changing conditions, inadequate design, 32 or improper maintenance. The result could be catastrophic if the hazard zone has been devel- oped intensively. Design Considerations and Physical Mitigation Methods When designing control measures, it is essen- tial to look well beyond the landslide mass it- self. A translational slide may propagate over great distances if the failure surface is suffici- ently inclined and the shear resistance along the surface remains lower than the driving force. Debris flows can frequently be better Figure 27. Retaining wall, Interstate 70,near controlled if mitigation efforts emphasize sta- Vail, Colorado (photograph by Colorado bilizing the source area along with debris con- Geological Survey). tainment in the runout area. An understanding of the geological processes and the surface- and ground-water conditions, under both natural Table 6. Physical mitigation methods (Colo- rado Geological Survey et aL, 1988). and human-imposed conditions, is essential to any mitigation planning. A. Physical Mitigation Methods for Slides and Some factors that determine the choice of Slumps physical mitigation are: 1. Drainage * type of movement (e.g., fall, slide, aval- a. Surface drainage anche, flow); 1) ditches * kinds of materials involved (rock, soil, 2) regrading debris); 3) surface sealing * size, location, depth of failure; b. Subsurface drainage * process that initiated movement; 1) horizontal drains * people, place(s), or thing(s) affected by 2) vertical drains/wells failure; 3) trench drains/interceptors, * potential for enlargement (certain types cut-off drains/counterforts of failures [e.g., rotational slides, earth- 4) drainage galleries or tunnels flows, translational slides] will enlarge 5) blanket drains during excavation); 6) electro-osmosis * availability of resources (funding, labor 7) blasting force, materials); 8) subsurface barriers * accessibility and space available for 2. Excavation or regrading of the slope physical mitigation; a. Total removal of landslide mass * danger to people; b. Regrading of the slope * property ownership and liability. c. Excavation to unload the upper part The physical mitigation of landslides usu- of the landslide ally consists of a combination of methods. d. Excavation and replacement of the Drainage control is used most often; slope toe of the landslide with other modification by cut and fill and/or buttresses is materials the second most frequently used method. These 3. Restraining structures are also, in general, the least expensive tech- a. Retaining walls niques (Figure 27). b. Piles Various types of physical mitigation met- c. Buttresses and counterweight fills hods are listed in Table 6. d. Tie rods and anchors 33 3. Direct protection Table 6. Continued a. Impact spreading walls b. Stem walls e. Rock bolts/anchors/dowels c. Vegetation barriers 4. Vegetation C. Physical Mitigation Methods for Rockfalls 5. Soil hardening 1. Stabilization a. Chemical treatment a. Excavation b. Freezing b. Benching c. Thermal treatment c. Scaling and trimming d. Grouting d. Rock bolts/anchors/dowels B. Physical Mitigation Methods for Debris e. Chains and cables Flows and Debris Avalanches f. Anchored mesh nets 1. Source-area stabilization g. Shotcrete a. Check dams h. Buttresses b. Revegetation j. Dentition 2. Energy dissipation and flow control 2. Protection a. Check dams a. Rock-trap ditches b. Deflection walls b. Catch nets and fences c. Debris basins c. Catch walls d. Debris fences d. Rock sheds or tunnels e. Deflection dams f. Channelization 34 PlaIep P atio? n Plan Preparation Determining the Need through land use management and the appli- cation of building and grading codes is essen- for a State Plan tially a function of local government (Sangrey and Bernstein, 1985, p. 9). In order to determine the need for a state land- slide hazard mitigation plan, individual states The purpose of a state landslide hazard must first assess the vulnerability of their pre- mitigation plan is to encourage and support lo- sent and future population to the hazard. cal mitigation efforts and address serious land- Vulnerability is the susceptibility or exposure slide problems, beyond local capability, that to injury or loss from a hazard. People, struc- threaten lives and property and have potential tures, community infrastructure systems regional or statewide implications. Strategies '(transportation, water supply, communications, and projects developed in,the planning process and electricity), and social systems are all are therefore based on an assessment of what potentially vulnerable. can be accomplished locally and the level of sup- An assessment of statewide vulnerability plemental assistance that will be required to to geologic hazards is a product of the technical lessen the problem. State and federal assis- assessment of the problem, based on scientific tance picks up where local efforts stop; gen- studies and investigations, and an assessment erally local resources must first be exhausted. of capabilities, in the public and private sec- A key element in, the planning process and tors, to respond to and mitigate the hazards a major recommendation of this guidebook is and potential impacts identified. Before re- the establishment of a permanent state 'organi- sources are invested in hazard mitigation zation, representing the various levels and re- measures, the social and economic costs and sponsibilities of government, to focus the atten- impacts associated with landsliding need to be tion of state government on natural hazard determined and put into perspective. mitigation issues. The next step in recognizing the overall Federal Disaster Relief and Emergency vulnerability of the state to the landslide ha- zard is the identification of specific commun- Assistance Act (Section 409) ities, areas, and facilities at risk. The existence In presidentially-declared disasters, the pre- and effectiveness of local programs and sys- paration of a state plan that identifies and tems for mitigating landslide problems in com- evaluates hazard mitigation opportunities is munities experiencing actual or potential im- mandated by Section 409 of the Robert T. Staf- pacts must then be determined. ford Disaster Relief and Emergency Assistance Although landslides can potentially affect Act (Public Law 93-288, as amended) as a entire regions or states, the hazards them- condition of receiving federal disaster assis- selves are local problems first, and local gov- tance. This requirement was originally enacted ernments remain on the `front lines" of the in 1974 under Section 406 of the Disaster battle to reduce losses. Relief Act to encourage identification, evalua- tion, and mitigation of hazards at the state and Landslide loss reduction in the United local government levels. The requirements of States is primarily a local responsibility. While the federal government plays a key role in re- Section 409 are triggered by a major disaster or search, in the development of mapping tech- emergency declared by the President and apply niques, and in landslide management on feder- to all types of declared emergencies and disas- al lands, the reduction of landslide losses 35 government, the private sector, and academia. ters. A hazard mitigation clause is incorporated Typically, the group would gather, interpret, into the FEMA/State agreement for disaster and assemble the technical information that assistance, thereby establishing the identifica- forms the basic structure of the landslide haz- tion of hazards and the evaluation of hazard ard mitigation plan. mitigation opportunities as a condition for re- The interagency efforts of post-disaster ceiving federal assistance. hazard mitigation teams in presidentially-de- The Federal Emergency Management clared disasters have demonstrated that such Agency (FEMA) is responsible for adminis- working groups representing a broad range of tering the Section 409 requirements and has state and federal agencies can successfully prepared implementing regulations (44 CFR develop a host of innovative and cost-effective 206, Subpart M) that specify federal, state, and mitigation ideas. local responsibilities under Section 409. Under The planning team should include indivi- the regulations, a state hazard mitigation co- duals knowledgeable about geology, engineer- ordinator is designated by a governor's author- ing, emergency management, and community ized representative to prepare a hazard mitiga- development and planning. Depending on the tion plan and to ensure its implementation. nature of landslide problems, the team might States may establish a group of individuals also include individuals involved in natural from state and local agencies to assist in pre- resources management, highway construction paring the "409 plan," which must be complet- and maintenance, state and regional planning, ed and submitted to FEMA within 180 days and others as conditions warrant. after the presidential declaration. The responsibilities of individual team With the passage of the Stafford Act in members would include researching and writ- 1988, a hazard mitigation funding program ing those sections of the plan that relate to was authorized for the first time under Section their area of expertise. Team members would 404 of the Act. This mitigation-measures fund- also participate in meetings with planners, ing program provides up to 50 percent federal emergency managers, policy makers, and funding for activities identified under Section elected officials in local and state government 404, thus making preparation of a good hazard and, to the extent possible, seek the input and mitigation plan more important than ever be- participation of private industry, professional fore. The identification of mitigation opportun- and volunteer organizations, and interested ities under this program follows the evaluation citizens. An initial analysis of existing mitiga- of natural hazards under Section 409. Total tion plans and emergency management capa- federal funds available under Section 404 are bilities in landslide-impacted jurisdictions will limited to 10 percent of the permanent restora- enable the planning team to identify the most tive work funded under FEMA's Public Assis- serious problems and to develop projects that tance Program. Implementation regulations for build on efforts already in progress. This as- Section 404 can also be found in 44 CFR 206, sessment of local landslide conditions and local Subpart M. capabilities to deal with them should identify a In state-declared disasters, some states wide variety of practicable mitigation solu- require the development of local hazard mitiga- tions. This will facilitate the coordination of tion plans as an eligibility requirement of state state support and the identification of unmet emergency relief. local needs that can be presented for possible state action. The Planning Team Local jurisdictions impacted by landslides States undertaking plan development should should be encouraged to form their own local first consider assembling a state planning team planning teams-composed of decision makers, to manage the research and writing of the planners, emergency managers, engineers, plan. The planning team could be in the form of geologists, and officials from law enforcement, a working group, directed by state representa- fire safety, and emergency medical services-to tives and supported by representatives of local formulate local plans and mitigation strategies. 36 The Planning Process hazard location, description, frequency, history, existing impacts, potential impacts, and, to the The planning process recommended for the de- extent possible, probability of occurrence. velopment of a landslide hazard mitigation The use of land-use maps in conjunction plan follows a series of steps that are basic to with detailed maps exhibiting the extent and mitigation planning: severity of landslide hazards in an area helps (1) analysis of the types of landslide haz- officials to determine vulnerability to land- ards in the state and a general assess- slides, mitigation priorities, and the most ap- ment of the vulnerability of people and propriate mitigation measures. property to the state's landslide hazards; Appropriate land use management, effec- (2) identification of specific areas of the tive building and grading codes, the use of well-designed engineering techniques for state where landslides have the most landslide control and stabilization, the timely serious or immediate potential impacts issuance of emergency warnings, and the avail- and a detailed analysis of their vulner- ability of landslide insurance can significantly abilities; reduce the catastrophic effects of landslides. All (3) translation and transfer of technical of these approaches require, as a starting point, the identification of areas where landslides are information on hazards and vulnera- either statistically likely or immediately immin- bilities to users such as decision mak- ent, and the representation of these hazardous ers,. community planners, and emer- locations on maps (Committee on Ground Fail- gency management officials; ure Hazards, 1985, p. 2). (4) assessment of resources and mitiga- The planning team should assemble exist- tion programs available in the public ing mapped landslide susceptibility data that and private sectors to deal with the portray the distribution of various types of identified potential impacts; landslides and the likelihood of their occur- (5) determination of local capability shortt- rence. The team will need maps sufficiently falls and unmet needs in order to ap- detailed to determine the character, location, ply technical and financial assistance and magnitude of landslide problems. where it can best contribute to the reduction of future losses; Step 2-Identification of (6) formulation of goals and objectives for Impacted Sites state and local landslide hazard miti- Once the nature and distribution of the hazard gation plans, and the development of and the vulnerability to landsliding of various cost-effective mitigation projects that communities, areas, and facilities has been de- address identified vulnerabilities; termined, site-specific evaluations of the poten- (7) establishment of a permanent state tial impacts of landsliding should be perform- hazard mitigation system to prioritize ed. Based on the hazard analysis, those sites and promote mitigation goals and ob- determined to present the greatest threat to jectives and to secure and direct fund- lives and property should be subject to further ing for implementation; site analysis and mitigation planning. (8) periodic evaluation and modification of Impact is the effect of a hazard event on the plan and planning process. people, buildings, and the infrastructure. The impacts of landsliding range from the incon- Step 1-Hazard Analysis venience of debris cleanup to the life-threat- A complete hazard analysis is the result of the ening failure of a landslide-formed dam. The identification of the state's landslide hazard simultaneous or sequential occurrence of other areas, the identification of the most vulnerable hazards such as flooding or earthquakes with locations, and the assessment of potential landsliding can produce effects that are greater impacts on people and property in vulnerable or qualitatively different from those produced areas. Where possible, the hazard analysis by landsliding alone. should provide planners with information about 37 and cooperative agreements with other juris- Step 3-Technical Information Transfer dictions and private industry. Private compan- As discussed in Chapter 5, individuals or ies have a vested interest in the mitigation pro- groups often do not take mitigative actions cess because private losses often exceed public because they do not understand the signifi- losses in natural disasters, and also because cance of the threat, what to do to reduce it, or private firms may receive insurance benefits lack information and training on how to do it. (lower premiums, reduced liability) for a demon- Therefore, once landslide hazard information strated commitment to reducing future losses. has been gathered, it must be communicated to The assessment of local capabilities should planners, policy makers, emergency response identify the most vulnerable elements of the personnel, and the public. Maps are one of the community, the current level of mitigation act- best methods of transferring such information. ivity, the status of emergency management Landslide information can be used in the de- planning, and opportunities for state and fed- velopment, review, and approval of land-use eral mitigation assistance. plans, community development plans, emer- The checklist provided in Table 7 can assist gency management plans, and hazard mitiga- local jurisdictions in preparing plans for land- tion plans. In order for landslide information to slide hazard mitigation and emergency man- be more widely incorporated into community agement as well as assisting state planning planning and planning for landslide mitigation, teams in assessing local mitigation efforts. the technical staff that produces the informa- tion must tailor it so that it is understandable Table 7. Types of informationthat should be and usable by the various parties involved in consideredin an assessment of a commun- the development process. Producers of informa- ity's landslide hazards and capabilities (mod- tion should also ensure that potential users are ified from Weber et al., 1983). aware of available data, as well as research planned or in progress. Conversely, nontechni- Maps A. cal users of landslide information should take 1. Base map steps to improve their skills in interpreting and 2. Landslide inventories applying the information. 3. Landslide susceptibility maps The difficulty of translating technical in- 4. Landslide hazard maps formation for nontechnical users highlights the B. Physical (Geologic) Information importance of retaining the services of qualifi- 1. Scope (boundaries of areas subject to ed technical experts throughout the planning landslides) process. According to Fleming and Taylor 2. Frequency (historical occurrences by (1980, p. 4), "solutions to the technical prob- date, location, description, and lems are only a part of the process of achieving impacts) landslide hazard reduction. The political prob- a. Reports lem of transferring the information into a b. Newspaper articles governmental system to reduce hazards and c. Eyewitness accounts damages is perhaps more formidable than the 3. Hazard characteristics technical one." a. Predictability b. Potential speed of occurrence Step 4-Capability Assessment c. Potential impact forces Capability assessment is a determination of d. Magnitude public, private, and volunteer resources in a e. Worst-case scenario community that are available to support emer- C. Social (Human) Information gency management and hazard mitigation act- 1. Land Use ivities designed to reduce losses from a particu- a. Existing (map) lar hazard. Resources include not only equip- b. Future (map) ment, supplies, and materials, but, more im- c. Zoning (map) portantly, people, expertise, plans, programs, 38 2. Emergency management activities Table 7. Continued a. Warning systems b. Emergency plans (life-saving, 2. Population at risk evacuation, facility-specific) a. Number of people/total dwelling c. Public -education/hazard awareness units campaigns b. Variability (difference in day/night d. Training exercises populations) 3. Local financial capabilities and needs 3. Property at risk (infrastructure) a. Funds available a. Use/function b. Major resource shortfalls b. Assessed value c. State and federal programs and 4. Economic activity at risk (commercial,, grants industrial, tourism) d. State and federal technical a. Employment assistance b. Gross revenues 5. Critical services and facilities at risk a. Access By comparing local risks and possible im- b. Police pacts with the capability of a jurisdiction to c. Fire respond to those risks, a state planning team d. Communications can identify major resource deficiencies, or e. Schools unmet needs, that become the basis for projects f. Health care (hospitals, nursing in the state plan. Unmet needs are technical homes) and financial resource needs that exceed the g. Utilities cap abilities of the communities at risk. In h. Emergency management facilities many cases, these resource shortfalls represent i. Thansportaion substantial obstacles to reducing the impacts of 6. Aggravating influences (roads, future landslides on people, property, and ess- structures, landscaping, removal of ential services. vegetation, or other land uses that contribute to landslide hazard) Step 5-Determination of Unmet D. Landslide Hazard Management Local Needs Capabilities 1. Landslide hazard mitigation activities Based on the analysis of local capabilities, un- a. Land-use regulations met needs that should be considered by state b. Land-use plans and federal governments are identified and a c. Building and grading codes state mitigation assistance strategy is formu- d. Design and location standards lated. In order to determine unmet needs, *e. Development and redevelopment specific human activities should be examined plans to evaluate potential impacts on public health f. Landslide control structures and safety, public and private property, com- g. Monitoring/instrumentation merce, and the community at large. Group h. Acquisition and relocation projects meetings and individual interviews can yield i. Public utility extension guidelines sufficient information to determine the most j. Planning team formation critical needs of local governments and to de- k. Land exchanges velop priority mitigation projects for state act- 1. Real estate disclosure requirements ion. Less urgent needs can be addressed in m. Lending and financing policies future projects. The state planning team n. Additional public works should also identify existing local mitigation o. Private sector involvement projects so that state projects can be coordinat- p. Special assessment districts ed to support their efforts. qq. Tax adjustments 39 gation face a number of important planning Step 6-Formulation of Goals challenges, including: (a) the preparation of and Objectives emergency management plans that ensure the Fundamental to a mitigation program is the timely warning and evacuation of people in establishment of a system for landslide mitiga- high-risk areas; (b) the formation of local tion planning and management at the state planning committees to identify unmet local and local government levels. The establishment needs and schedule the implementation of mit- of a permanent state system to effect mitiga- igation projects; (c) the coordination of public, tion projects should be considered. This man- private, and volunteer resources; and (d) the agement system would help ensure that: integration of landslide hazard information * existing hazardous conditions are dealt into community development plans in order to with expeditiously, protect existing development and guide, dis- * new landslide hazards are assessed and courage, or restrict future development in prioritized, landslide-prone areas. * new options are developed and evalu- Local hazard mitigation and emergency ated, planning are generally carried out separately * intergovernmental and interagency from the basic planning of local government. technical advice and mitigative action Integrating hazard information into the com- can be coordinated, prehensive or master plan of a community, * priorities are established for high- and however, better enables a jurisdiction to guide moderate-risk situations that are the activities of builders, investors, and devel- beyond local government capability, opers in areas known to be hazardous. Com- * decisions are made and funding munities that have an adequate base of tech- obtained and spread over a period of nical information about local landslide prob- time that is commensurate with state lems, and that have succeeded in applying this fiscal capabilities, information to development and planning de- * feedback is evaluated and needed pro- cisions, have met an important precondition to gram adjustments made, and most types of mitigation. Land-use plans that * a systematic approach to mitigation is consider available hazard information demon- established. strate to developers and to the public that public health and safety concerns are import- Local Landslide Hazard Mitigation ant factors in community development. Accord- Local jurisdictions should institute mitigation ing to Olshansky and Rogers (1987, p. 957), programs that coordinate landslide hazard in- "By incorporating landslide hazard information formation and mitigation needs with state gov- into long-term local plans, local governments ernment and the private sector. Local mitiga- give developers advance notice of land use tion systems should effectively employ state policies and the reasons for those policies." assistance and be ready to take on new prob- lems as solutions to old problems are found. Development of Mitigation Projects Local mitigation plans need to be in place so The identification of areas in the state that are that work on mitigation projects can begin as vulnerable to catastrophic landslide losses will soon as funds become available. enable the planning team to formulate the Effective local systems are important to goals and objectives of the state plan, which state planning because they provide direction may be expressed in the plan in the form of for state action. A comprehensive local hazard prioritized mitigation projects. With the sup- mitigation program should be based on com- port of the planning, technical, and policy-mak- munity consensus, developed through local ing staff of state and local agencies that have planning committees with citizen support and resources, capabilities, or statutory responsi- involvement, and should conform to local goals bilities relating to landslide hazard manage- and objectives and budget constraints. Local ment, the planning team should be able to governments involved in landslide hazard miti- develop an initial group of projects. 40 A wide range of project ideas and opinions, Step 7-Establishment of a Permanent representing the perspectives of planning, geol- State Hazard Mitigation Organization ogy, engineering, emergency management, pri- A permanent state hazard mitigation organi- vate industry, elected leadership, and others, zation should be created to coordinate the re- should be solicited to enable the planning team sources of state, local, and federal agencies to determine the cost effectiveness, feasibility, with landslide hazard mitigation responsibil- and political and social implications of each ities and authorities. For states with serious possible approach. The highest initial priority landslide problems, establishment of a perm- should be assigned to those projects that estab- anent organization institutionalizes in state lish a permanent system in state government government the consideration of opportunities for continuous support of state hazard mitiga- to reduce landslide losses. In Colorado, this has tion opportunities. A second priority should be been accomplished by an Executive Order state support to long-term mitigation programs (Figure 28) that formalizes landslide hazard in local government and the private sector. mitigation planning within a natural hazards Another ongoing priority should be the identi- mitigation council. fication of and participation in state and fed- States with no existing system for hazard eral programs that can provide funding support mitigation should consider establishing an for mitigation initiatives. organization that also addresses and promotes Although implementation of many recom- the mitigation of other hazards impacting the mendations may be difficult if financial re- state. Most of the public agencies involved in sources are linited, government agencies landslide hazard mitigation-those concerned should be encouraged to use the plan and its with geology, natural resources, highways, identified projects as a resource in formulating climatology, water resources, emergency man- annual work programs, budgets, and policy agement, and others-are also involved with statements concerning landslides. Projects that problems of flooding, drought, and, depending modify existing programs or improve coordina- upon location, hurricanes, and earthquakes. tion are usually relatively low-cost and stand Although the focus and extent of short-term the best chance of being implemented first. mitigation activities at any given time may Funds to implement the more costly projects depend upon the prevailing threats, the organ- should be aggressively sought from state legis- ization should maintain a broader, long-term latures, the federal government, and the priv- perspective on all of a state's natural hazards. ate sector. An all-hazards approach should result in an Projects recommended in the state plan efficient, multi-purpose process that can gain should include a brief statement of the prob- the support and approval of state leadership lem, a general statement of the recommended and the public. solution, a description of short- and long-term The role of the state mitigation organiza- initiatives, a designated lead agency; and a pre- tion should essentially be a continuation of the liminary estimate of cost effectiveness, where activities performed by the state planning possible. Projects should contribute toward an team and those coordinating agencies with a effective and coordinated state/local landslide role in landslide mitigation that participated in management system, and should be flexible the development of the plan. One type of org- both in content and priority to allow for modi- anization might consist of a state mitigation fication during the implementation process. council supported by working groups. The Local jurisdictions should report their accom- council would be made up of decision makers plishments and important unmet needs to the selected from key state, local, and federal agen- state mitigation organization so that new cies and could include representatives from the state/local strategies can be developed. New governor's office and the state legislature. Re- projects should be introduced into the system presentatives from local and regional govern- as new landslide threats are identified and as ments and academia may also be included in new approaches to old problems are found. working groups. 41 B 044 89 Executive Order Page Two STATE OF COLORADO The Speaker of the House of Representatives, the President of the Senate, the Minority Leader of the Senate and the Minority Leader of the legislative one CHAMBIERS EXECUTIVE appoint may each of Representatives House 136SlaeCOpitol representative. All members will serve for a term of two years with B 044 89 D.on-, Colorado2v11,92 -- reappointments permitted at the pleasure of the Governor. The Governor (303)00003-1 Phone will appoint the chairperson. 2. The chairperson will appoint a steering committee and an executive Roy Rome, secretary to carry on the administrative activities of the council. G.--rn EXECUTIVE ORDER Theresponsibilities assigned to the council are to: 3. OF N COUNCIL THEIMPLEMENTATION FOR ESTABLISHIA G HAZARDS COLORADO IN MITIGATION OFNATURAL STRATEGITOMANAGE ES a. Identify vulnerability to various natural hazards and evaluate the options available to mitigate such risks. various natural hazards have caused physical and financial WHEREAS, impacts in Colorado and will continue to do so; and b. Review current mitigation plans for such hazards as wildfires, droughts and avalanches. these impacts have resulted in unexpected costs to state WHEREAS, and local governments as well as degradation of the state's health, c. Develop a unified management strategy with recommendations safety, environment, infrastructure and economy; and concerning state, federal or local mitigation responsibilities. the opportunities to significantly manage floods, WHEREAS, d. Prioritize hazards statewide. landslides, wildfires and other natural hazards are identifiable and should be executed as funding is available; and e. Assist local government in seeking funding to implement hazard mitigation recommendations. mitigation recommendations can be effectively prioritized WHEREAS, and managed by a state council, supported by interagency working groups; f. Meet at the call of the chairperson, but no less frequently and than once a year. WHEREAS,need exists to provide formal recognition, authority and a g. Prepare an annual work program and status report covering responsibilities to this organizational structure; progress achieved and provide periodic updates to the Governor and the state legislature. THEREFORE,Roy Romer, Governor of the State of Colorado, by 1, NOW, virtue of the authority vested in me under the constitution and laws of of the public Inform local government and the general h. the State of Colorado, including the Colorado Disaster Emergency Act of activities and recommendations of the council. 1973, 24-33.5-701, et seq., hereby Order: The council is directed to place high priority on use of the Colorado 1. The Colorado Natural Hazards Mitigation Council is hereby created. Flood Hazard Mitigation Plan and Landslide Hazard Mitigation Plan, and The council will be.chaired by the Colorado Department of Natural should coordinate and prioritize the projects contained in these plans Resources and consist of as many as 25 representatives. The following and any other plans dealing with natural hazards. organizations or groups shall be appointed by the Governor: Given under my hand and the The Governor's Office - Executive Seal of the State State departments of Natural Resources, Highways, Local Affairs, - of Colorado, this _2,!a day Public Safety, Health and Agriculture The Colorado Municipal League and Colorado Counties, Inc. - The Natural Hazards Center, University of Colorado - Business community - The Federal Emergency Management Agency (Region VIII) and the - Roy Romer7 r Oceanic and Atmospheric National Weather Service (National Governor VJ Administration) U.S. ArmyCorps of Engineers - Elected local officials from areas of the state with high-risk - natural hazards The general public - .I . I Figure 28. Executive Order establishing Colorado Natural Hazards Mitigation Council. The council should be responsible for prior- implementation, (2) monitor identified land- itizing strategies and projects, securing and slide areas and collect and interpret informa- directing funding, and monitoring overall prog- tion about emergency situations as they occur, ram effectiveness to ensure that policies and (3) prepare new projects as needed to meet directed measures are implemented in a timely changing conditions, (4) implement projects as and efficient fashion. Since funds for the imple- funding becomes available, (5) recommend pro- mentation of many of the recommended pro- jects for funding by government and the priv- jects will not likely be immediately available, ate sector as specific needs arise, and (6) pro- an ongoing and aggressive search for funding vide technical support to the council, including sources will be a major role of the council. recommendations on project priority. State and federal support should be obtained Step 8-Review and Revision immediately for those projects that address landslides where potentially catastrophic or A continuous process for evaluating mitigation serious economic impacts have been identified. progress and for maldng adjustments to the The responsibilities of the working groups program should be a part of any hazard mitiga- will be to: (1) review risks and options and pro- tion system. Procedures for review and revision vide additional information to the council once of plans and the planning process are discussed projects have been selected from the plan for in the following chapter. Ii 43 n~ (0111JAST (Q) Review and Revision of the Plan and the Planning Process ways, homes and businesses, and facilities and In order to ensure the timely implementation services, so that decisions can be made regard- of mitigation projects recommended in the ing the level of mitigation assistance required state landslide mitigation plan, the proposed to reduce losses in an area and so that the state hazard mitigation organization will need cost-effectiveness of individual projects can be to establish an ongoing system for evaluation determined. The inventory should provide a and modification of the planning process. In summary of landslide incidents and associated addition to tracking progress of the program financial impacts on individuals, companies, and providing a record of local and state mit- municipalities, and local, state, and federal igation achievements, a review process per- governments. The inventory should include a mits the adjustment of program priorities. It list of occurrences, the location, type of event, allows the state mitigation organization to cause of event, facilities damaged, total costs of monitor and become familiar with the types of damages and/or repair and replacement, and problems that are likely to be encountered in maps and photographs of affected areas. To the future projects, so that planning strategies can extent possible, an estimate of indirect be developed. damages should also be made. The criteria, decisions, and methods used in applying the landslide research findings to Understanding the cost and significance planning and decision making can be of value of natural disasters allows officials at all levels to other jurisdictions in which similar hazards of government to make decisions about how exist, and for which adequate landslide in- much money should be allocated to disaster formation is available. The adaption to, and prevention rather than to the repair of dam- adoption by, other jurisdictions depends upon aged facilities and disaster relief after an event the presence of similar public awareness, en- (Fleming and Taylor, 1980 p. 1). abling legislation, hazard issues, priorities, community interest, innovative decision makers, and staff capabilities (U.S. Geological Evaluation of Mitigation Projects Survey, 1982, p. 44). and Techniques While the exact nature of the evaluation The state hazard mitigation organization system should be determined by the mitiga- should establish procedures for the periodic tion organization in each state based on speci- review and evaluation of the status of individ- fic needs, it is recommended that any system ual mitigation projects, those proposed, com- for evaluating the success of state landslide pleted, and in progress. The effectiveness of hazard mitigation programs include the landslide hazard mitigation efforts varies ac- following components: cording to the physical, economic, and political * an inventory of landslide costs, conditions existing in the local areas. Accord- * an evaluation of mitigation projects and ing to Kockelman (1986, p. 47), "Very few techniques, systematic evaluations have been made of * cost-benefit analyses of local mitigation hazard-reduction techniques, even fewer for programs. landslides specifically." A careful assessment of Inventory of Landslide Costs the cost effectiveness of each project will help guide decisions of the state hazard mitigation An effort should be made to document all land- organization about the implementation of slide-related losses in the state as they occur, future projects. particularly direct damage to roads and high- 44 The occurrence of actual landslide disas- Analyses of Local Mitigation ters and the identification of new landslide Programs threats will also necessitate an adjustment of A critical feature of the proposed planning pro- planning priorities. Maintaining flexibility in cess is the development and maintenance of the system will enable the state organization to lines of communication between local and state apply limited funds and resources to efforts mitigation systems and between state and that are most likely to contribute to the reduc- federal systems. In order for state mitigation tion of future losses. assistance to adequately support local efforts, Examples of Innovative Mitigation local programs must periodically report to the state their unmet needs, i.e., desired projects Approaches that are determined locally to be needed, but The evaluation process will produce a record of are beyond local resource capabilities. both mitigation achievements and failures, Local reports of mitigation needs and each of which will help educate officials in- activities in progress will help state officials volved in solving landslide problems. Examples determine program effectiveness and funding of innovative mitigation techniques that have priorities. Landslides that present potenti- been successfully implemented are not only of ally catastrophic impacts and local mitigation value as guidance in other jurisdictions, but programs that have demonstrated the ability to will also provide justification for gaining funds produce mitigation results should be among and support for new projects. Additionally, the top priorities considered for state or fed- promoting mitigation success stories increases eral assistance. U public education and awareness of landslide hazards, as well as public confidence in govern- ment hazard mitigation programs. 45 Approaches for Overcoming Anticipated Problems inating jargon and arriving at acceptable term- The process of developing and implementing inology for planning may require some com- long-term state and local landslide hazard mit- promise among team members. On-site visits igation programs is beset with certain obsta- to selected landslide areas within the state and cles to success. The most significant problem is the collection of pertinent reports and litera- generating the resolve and motivation to or- ture are important steps that the planning ganize, implement, and fund such a broad-scale team should undertake. It may also be useful effort. The expenditure of the time and money to organize a technical advisory committee that necessary to derive long-term benefits is not would meet occasionally to review draft plan always attractive to state or local leaders. Un- material and to provide overall guidance and fortunately, sometimes only an actual disaster recommendations. will provoke action. Developing creative ap- proaches to financing and obtaining leadership Management Problems support for mitigation projects is an ongoing challenge to mitigation proponents. Neverthe- The research and writing efforts involved in less, it is clear that the ultimate costs to tax- creating a state plan will involve geologists, payers are likely to be significantly increased engineers, planners, emergency managers, when mitigation activities are postponed. elected officials, and interested citizens. The integration of these many points of view is a Organizational Problems difficult management task but necessary if the plan is to be practical and usable for the man- The need for the plan preparation team and agement and mitigation of landslide hazards. subsequent permanent hazard mitigation or- The project manager, with guidance and help ganization to be broadly representative, multi- from other members of the team, must manage disciplinary, and intergovernmental presents this work and establish tasks, assignments, some immediate organizational and coordina- and completion dates. In order to obtain a clear tion problems. An important first step in or- and consistent document, an editor with some ganizing such a group is to ensure that all background in natural hazards, earth sciences, elements of the team concur with their roles planning and/or mitigation technology should and assignments before work begins. This be employed. agreement should be formalized in a contract, memorandum of understanding, or some other Financial Problems document. A further recommendation is that a project manager be appointed early on to Regardless of the source or sources of funding schedule meetings, tend to administrative and for development of the plan, careful manage- financial details, ensure deadlines are met, and ment of a budget will be required to ensure all direct and coordinate the effort. project expenses are accommodated (staff costs, The project manager should be selected travel expenses, fees for editing, printing, from the state organization designated as the graphics, etc.). Since the planning process will lead agency and one of his or her first tasks is involve several agencies working on independ- to integrate the broad range of technical, plan- ent tasks, periodic reviews of the budget should ning, community, and organizational expertise be conducted to prevent overruns. available into an effective working team. Elim- 46 Coordination Problems approve the plan should be kept informed of the work and made aware of the plan well in Because of the difficulty involved in man aging advance of publication. such a comprehensive effort, it is important to Finally, in order to produce a single, clear set realistic deadlines and to allow sufficient draft of the plan, it is also necessary to time for necessary coordination of involved coordinate the word processing systems of the agencies and integration of the various work participating agencies. If compatibility between -elements. The involvement of all levels of gov- computer systems is not possible, the various ernment will necessarily affect progress in plan elements of the plan may have to be re-entered preparation, and time must be allowed for into one system. The time and expense of plan obtaining concurrence and approval from gov- publication (typesetting, printing, distribution) ernmental agencies contributing to the miti- should also be determined as soon as possible gation process. 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