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This file is available in Adobe Acrobat PDF. Click here to Download Cover Picture County of Kauai Natural Hazard Risk & Vulnerability Assessment and Hazard Mitigation Workbook © December 2002. Prepared by the University of Hawaii Social Science Research Institute. This document has been prepared for the County of Kauai using resources developed by federal and state partners. These include:
We thank all of the individuals behind the organizations listed above and all of those who have contributed to the hazard mitigation planning efforts in Hawaii State. Click here to Download NOAA and CZM Hawaii logos This document is funded in part by the National Oceanic and Atmospheric Administration and the Hawaii State Coastal Zone Management Program. KAUAI COUNTY Table of Contents SECTION 1: Introduction (Up to TOC) The purpose of this document is to allow community groups and organizations to develop hazard mitigation plans on Kauai. It is based in part on a hazard mitigation planning process facilitated by Kauai Civil Defense in partnership with the Social Science Research Institute of the University of Hawaii with support from FEMA, State Civil Defense and the Hawaii Coastal Zone Management Program. It provides an introduction to hazard mitigation planning, identifies sources of hazard mitigation information and guidance documents and outlines the steps in the hazard mitigation planning process. Natural Hazards in Kauai County (Up to TOC) The County of Kauai includes the islands of Kauai and Niihau. Kauai is geologically the oldest of the main Hawaiian Islands. Three hurricanes have severely impacted Kauai over the past 40 years. Hurricane Iniki, for example, had gusts up to 160 miles per hour, destroyed 1,421 houses, and damaged over 13,000 homes in 1992. Other natural hazards also threaten Kauai. In September of 1996, heavy rains led to flooding of Hanalei town and temporary closure of the Hanalei Bridge, the only way residents can access the rest of the island. Heavy rains frequently close bridges and landslides on the highway past Anahola are common. Kauai has had twenty-six tsunamis of three feet or more in height since 1819 with wave heights of up to 35 feet (Summary maps showing the history of hazards, including heavy winds, tsunami, high waves, and flooding, have been included in the Appendix for reference.) The best way to deal with natural hazards is to recognize that they occur and to take action that will minimize the impacts. The term that agencies commonly use to describe the measures taken to reduce the effects of natural hazards is "hazard mitigation." This workbook explains the planning process to mitigate hazards, using risk and vulnerability assessments. Hazard Mitigation: Why is it important? (Up to TOC) Each year, natural hazards worldwide result in loss of life and economic impacts totaling billions of dollars. Hurricane Iniki left Kauai with an estimated $1.8 billion in economic losses, which does not account for all of the personal hardship suffered by families who lost jobs and belongings. The dollar estimate also does not include the losses to the economy and lost income for residents, which lasted over a decade. Many times appropriate mitigation actions taken before a hazard event
occurs can reduce the immediate impacts and prevent long recovery periods.
Mitigation can cost money, but FEMA officials have estimated that for
every dollar spent on mitigation, at least seven dollars have been saved
in response and recovery costs following a disaster. Besides the federal requirements for funding, mitigation makes good common sense. For example, regularly scheduled clean-ups of streams and areas near streams prevent stream pollution, debris and runoff in nearshore waters. It can also prevent flooding along the stream during heavy rainfall. Maintenance of the water pipes by the county water departments reduces leaks and the cost of water for public and private use. It also helps to conserve water in the event of a drought. Preparedness, Response, and Mitigation Activities (Up to TOC) Often, there is confusion about the difference between disaster preparedness or response planning and mitigation. Both are important and constitute different phases of the disaster cycle. Response planning occurs during the preparedness phase of the disaster cycle, but the activities usually occur after the impact of a natural hazard. Mitigation should also be undertaken prior to a disaster occurrence. The focus of mitigation is to reduce the impact of a hazard event on life, property, and the economy. Mitigation activities may enhance and preserve natural resource systems, and these benefits may be felt without the occurrence of a disaster. Table 1. Comparison of Example Activities for Response and Mitigation
Conducting Risk and Vulnerability Assessments (Up to TOC) The first steps in hazard mitigation planning are hazard to identify the hazards that affect a community, to assess the risk of disaster losses and evaluate the social, economic, and environmental vulnerability of a community. The Federal Emergency Management Agency and the National Oceanic and Atmospheric Administration Coastal Services Center have developed guidance documents for communities on how to conduct risk and vulnerability assessments. This workbook does not attempt to replicate these materials but to provide excerpts and information on how to obtain these resources. These guidance documents themselves are available for free either by ordering the documents from the agencies or downloading from the websites provided. 1) Understanding Your Risks - identifying hazards and estimating losses (FEMA 386-2) provides step-by-step guidance on how to do a risk assessment. http://www.fema.gov/fima/planning_toc3.shtm Through a series of general and hazard specific guidance and worksheets, this guide can help states and communities to determine - 1) which natural hazards affect their jurisdiction; 2) what geographical areas are vulnerable to the hazards; 3) what structures and infrastructure will be affected; and 4) to what degree they will be affected, as measured through dollar losses. The document is multi-hazard in scope. Flood, earthquake, tsunami, tornado, coastal storm, landslide and wildfire are addressed. For communities dealing with multiple hazards, guidance is provided on how to develop a composite loss estimate. Once the risk assessment is completed, states and communities will have the information necessary to develop a strategy and plan for reducing their losses. This publication is available from the FEMA Publication Warehouse (1-800-480-2520).
Request by FEMA No. 386-2. It can also be downloaded as Adobe Acrobat
Reader files (.pdf files) directly from the website. The North Carolina Vulnerability Assessment Tool is an informational aid designed to assist communities in their efforts to reduce hazard vulnerability. The CD-ROM contains a methodology, developed by the NOAA Coastal Services Center, that helps local and state governments determine and prioritize their localities' vulnerability to coastal hazards. The website contains an order form for the CD-ROM and all of the information from the CD has been posted on their website so that communities have access to this information through the internet. Overview of Kauai Assessment Methods (Up to TOC) To conduct the risk and vulnerability assessment for Kauai, the project team used a combination of methods drawn from the guidance documents discussed above and modified for Kauai. The methods can use a range depending on the technical expertise, capability, and resources available to the community or government undertaking the assessment. STEP 1: Ask Questions and Assess Risks. (Up to TOC) The following set of questions will help the community to evaluate their
situation and determine their needs for hazard mitigation planning. Do you know...
These questions will help to guide a community or organization through a hazard assessment process. One of the most useful tools in developing a risk and vulnerability assessment
is a geographic information systems (GIS) and maps produced from it. It
is easier to point to areas on a map than refer to a list, and it is easier
for people to see where their homes and businesses are located in relation
to a particular hazard. Furthermore, maps improve communication about
hazard risks between communities or organizations and disaster planners,
engineers, and emergency response personnel. Not every community has access
to GIS, but it is still possible to gather paper maps of local areas and
identify risks by hand. Step 2: Conduct a Hazard Analysis Click here to download image of Kauai Hazard Analysis Information should be gathered for all of the potential hazard risks. The analysis should include historical information; however, it is important to remember that even though no one can remember a particular hazard, it does not mean that the area is not vulnerable in the future. For example, earthquakes are not common in Hawaii, but Hawaii State is in a high-risk zone for seismic activity. The more that the data includes spatial and visual information, such as maps, photos, and video, the easier it will be to convey risks to decision-makers and communities. STEP 3: Identify Assets Identify facilities, property, infrastructure, habitat and other things of value for the community. These will be the things that it is most important to protect. The list will fall into categories of critical facilities, building stock, public infrastructure, economically important areas or facilities, environmentally important areas, and socially important areas. Community members identified the following list of assets during several meetings held as part of Kauai's Project Impact and as part of the hazard mitigation planning process conducted by the Hawaii State Hazard Mitigation Forum. 1. Emergency Services Infrastructure STEP 5: Vulnerability Assessment Vulnerability is the susceptibility of resources to negative impacts from hazard events. It is these negative impacts that concern most people. While the study of hazards, risks, and probabilities is an important component of vulnerability, alone it does not provide resource managers with the information necessary to prioritize mitigation alternatives or measure improvements in mitigation. In order to make efficient use of your mitigation resources, it is not enough to know if, when, or even where a hazard event will strike. You need to know where your vulnerabilities are so you can make the most of your pre-disaster planning efforts. (NOAA Coastal Services Center, 1999, Community Vulnerability Assessment Tool, http://www.csc.noaa.gov/products/nchaz/htm/tut.htm). Determine past losses by sector using the following sources of data:
Determine the value of assets and potential losses using the following sources of data:
Prepare assessments to look at the vulnerability in each area, and then consider overall vulnerability to multiple hazards. The return period, frequency, and severity of the natural hazard should be considered. The following diagrams (taken from the NOAA/CSC Community Vulnerability
Assessment Tool illustrate the vulnerability assessment phases of the
project. Critical Facilities Analysis Click here to download image of Critical Facilities Analysis The following diagram shows identification of critical facilities in Hanapepe from a flood developed as part of Kauai Project Impact. Click here to download image Societal Analysis Click here to download image of Societal Analysis The following picture shows the map for the social analysis developed
as part of Kauai Project Impact: Click here to download image Economic Analysis Click here to download image of Economic Analysis The following picture shows the map for the economic analysis developed
as part of Kauai Project Impact: Click here to download image Environmental Analysis Click here to download image of Environmental Analysis The following picture shows the map for the environmental analysis developed as part of Kauai Project Impact: Click here to download image Mitigation Opportunities Analysis Click here to download image of Mitigation Opportunities Analysis Develop a Hazard Mitigation Strategy (Up to TOC) The opportunities analysis can then be used to help develop the hazard mitigation strategy. The strategy should detail the hazard risks and vulnerabilities and describe a strategy for addressing potential hazards. It should identify gaps in data, planning, and policies that should be considered over time. A strategy to address these gaps should be included. The hazard mitigation strategy will be a living document that will change over time as new studies are conducted and as technology improves. The strategy should be continuously updated so that it will meet the needs of the community should they confront a natural hazard. The following outline describes the elements that should be included in the hazard mitigation strategy, and it can be referenced during the writing of the strategy: A. Hazard Mitigation Goals C. Mitigation Projects D. Implementation of Mitigation Measures Plan Maintenance Procedures A. Monitoring, Evaluating,
and Updating the Plan Note: The GIS work should provide a basis for the hazard, risk and vulnerability
assessments that should improve the data and information used for the
mitigation strategy. The mitigation strategy should contain proposals
for projects and will be considerably longer than implied by the detail
in the outline. SECTION 2: Natural Hazard History and Hazard Mitigation in Kauai (Up to TOC) HURRICANES (Up to TOC) What Is a Hurricane? Hurricanes, tropical storms, and typhoons are collectively
known as tropical cyclones. They are among the most devastating, naturally
occurring hazards in the United States and its territories. Tropical cyclones
are classified as follows: Hurricane - An intense tropical
weather system with a well defined circulation and maximum sustained winds
of 74 mph (64 knots) or higher. In the western Pacific, hurricanes are
called "typhoons." Similar storms in the Indian Ocean are called
"cyclones." Tropical Storm - An organized
system of strong thunderstorms with a defined circulation and maximum
sustained winds of 39 to 73 mph (34-63 knots). Tropical Depression - An organized
system of clouds and thunderstorms with defined circulation and maximum
sustained winds of 38 mph (33 knots) or less; Saffir-Simpson Hurricane Scale
What causes most of the hurricane-related damage? Storm surge, rain, and wind cause most of the damage associated with hurricanes. · Storm surge floods and erodes coastal areas, salinizes land and groundwater, contaminates the water supply, causes agricultural losses, results in loss of life, and damages structures and infrastructure. Rain damages structures, infrastructure, and agriculture and results in loss of life. Hawaii's topography focuses the rains on mountain slopes, causing flash flood and landslides. Strong winds can result in loss of life, create tremendous amounts of debris (which impact utilities and transportation), cause agricultural losses, and destroy lightly constructed buildings (e.g., tofu-block houses). What are the chances of a hurricane destroying my home? No one knows. We can only make judgments using past history. Almost no one expected that a hurricane as powerful as Iniki would strike Hawaii. The best we can guess is hurricanes in the future will probably hit Hawaii as frequently as they have in the past. We know that since 1950 five hurricanes or tropical storms have caused serious damage in Hawaii. Hurricane Nina in 1957 produced record winds in Honolulu. Hurricane Dot did a lot of damage on Kauai in 1959. Hurricane Iwa did extensive damage on Kauai and Oahu in 1982. Hurricane Estelle produced very high surf on Hawaii and Maui and floods on Oahu in 1986. Hurricane Iniki did extensive damage on Kauai and Leeward Oahu in 1992. Since 1950, seven other tropical storms or hurricanes could have caused serious damage. These include Hurricane Fernanda in 1993, Hurricane Emilia in 1994, and Hurricane Daniel in August 2000. What are the potential losses from future hurricanes on Kauai? If a Category 1 storm as strong as Hurricane Iwa, with winds gusting at 74 mph, strikes any of the islands in the state, we can guess from past experience that about 12% of the houses and apartments could be destroyed or heavily damaged and about 18% would probably experience minor damages. If a Category 3 storm strikes any island with the same force as Iniki, with winds raging at 130 mph, we can guess that about 38% of the homes will be heavily damaged or destroyed. An additional 40% will probably have minor damages. The following information was extrapolated from Kauai Damage in 1982 and 1992. ($billion in 1992)
Source: Hawaii Coastal Hazard Mitigation Planning Project, Office of Planning, December 1993 Where have strong winds been measured on Kauai? Kauai has experienced exceptionally strong trade wind events, winter Kona storms, and passing tropical storms and hurricanes. Occasionally, trade winds strengthen to between 25-40 mph for several days. Strong winds associated with winter Kona storms can reach great velocities. Passing tropical storms and hurricanes and have been reported at over 100 mph. Often, winds accelerate as they descend from the mountains to the coastal plain. In many instances, the highest recorded gusts associated with passing storms have occurred on the side of the island opposite the storm's approach as winds burst in downdrafts across ridge crests from the steep pali to the coast below. On Kauai, numerous high wind events have affected the entire island, and many were associated with passing storms. Hurricanes Dot (1959), Iwa (1982), and Iniki (1992) were exceptionally damaging. Hurricane Dot packed sustained winds of 75 mph with gusts of 165 mph as it passed directly over Kauai. Winds and flooding led to $5.5-6 million in agricultural losses and hundreds of houses and trees were damaged. Hurricanes Iwa and Iniki both produced high waves ranging 20-30 feet and winds over 125 mph. Although Hurricane Iwa passed to the northwest of Kauai, the high surf it produced, combined with a 5-6 foot storm surge, flooded 600 feet inland in areas between Kekaha and Poipu and caused $312 million in damage. Ironically, despite the massive flooding and wind damage to the Poipu area, redevelopment following Iwa occurred in precisely the same location, only to be devastated 10 years later by Hurricane Iniki. Today, these same areas are once again densely developed. On September 11, 1992, Hurricane Iniki, the strongest and
most destructive hurricane to hit the Hawaiian Islands, made landfall
just west of Port Allen on Kauai's south shore. Iniki's winds were sustained
at 130 mph and gusts topped 160 mph. Winds and waves destroyed 1,421 houses
and caused minor to heavy damage to some 13,000.
Mitigation Activities at Home Homes can be destroyed by high winds. Flying debris can break windows
and doors, allowing high winds and rain into your house. High winds can
also cause weak places in your home to fail. Strengthen these areas in
your house: roofs, exterior doors, windows, and garage doors. Other mitigation
activities include clearing debris from the area and building a safe room
in your home. Roof: Exterior Doors: Windows: Garage Doors: Clear Debris: Safe Rooms: What can I do at work? It is estimated that 43% of businesses never reopen following a local disaster, such as a hurricane. Therefore, it is important business owners take proactive steps to protect their business, because they are a vital part of the community. The Small Business Administration (SBA) and the Institute for Business & Home Safety (IBHS) suggest that small business owners develop a Disaster Plan that includes mitigation activities. These activities are divided into the following categories:
Facilities (Buildings & Equipment)
Operations
Critical Information and Communication
Insurance
FLOODS (Up to TOC) What are floods and flashfloods? The distinction between a flood and "flash-flood" is usually determined by the amount of warning (less than six hours for a flash-flood) that affected areas might receive prior to the flood conditions. Flash floods may trigger hazardous events such as mud and landslides, structural bridge failures, and other threatening conditions. Rainfall intensity and duration are the primary source of flash floods. Intensity is the rate of rainfall, and duration is how long the rain lasts. Other factors include topography, soil conditions, and ground cover. Floods are a long-term event and may last several days, or even weeks. Hurricanes and earthquakes directly cause flood conditions such as "storm surge" or tsunami respectively. There are also floods that have characteristics associated with the geographic areas they are in, such as river, coastal and urban flooding. River Floods in Hawaii are usually triggered by hurricane or tropical storm rains. Coastal Floods are caused by winds generated from tropical storms and hurricanes or intense offshore low-pressure systems that can drive ocean water inland and cause significant flooding. Urban Floods are triggered because the paved streets cannot absorb the rainfall. Therefore, the streets become a river and people can lose their property and sometimes their lives. What is the difference between "watch," "warning," and "advisory?" The National Weather Services uses specific words when they issue alerts to the public about dangerous flood-related conditions. Flash flood watch: A flash flood is possible in the area. Stay alert. Flash flood warning: A flash flood is imminent or occurring; take immediate action. Urban and small stream advisory: Flooding of small streams, streets, urban storm drains, and low-lying areas. The Flood Risk in Kauai According to the Department of Land and Natural Resources, floods from tsunamis, hurricanes, and rainstorms caused more than 350 deaths, and over $82 million in property damage, from about 1860 until 1962. Damage from floods from 1963 through 1982 total about $395 million. From January 1983 to July 1992, twelve deaths have been attributed to flooding. The 1987 New Year's Flood caused an estimated $35 million in damage. Floods in March 1991 resulted in damage estimated at $10-$15 million. In December 1991, floods damaged an estimated $7 million in property. The National Flood Insurance Program has paid a total of $51.7 million in claims since 1974 to Hawaii's policyholders, $35.6 million of which were related to Hurricane Iniki. Though small compared to the $1.6 billion in insurance claims paid by the private industry following Iniki, the number and total value of flood insurance policies has more than doubled since 1994. Information on the National Flood Insurance Program appears below. In the appendix, there are tables with flood terminology and discussion of the community rating system. National Flood Insurance Program The National Flood Insurance Program (NFIP) provides federally-backed flood insurance to property owners in communities that regulate development in floodplains. The United States' Congress established NFIP to "reduce the loss of life and property and rising cost of disaster due to flooding." The National Flood Insurance Program is a voluntary program based on agreements between federal and local governments. In order to participate, a community must adopt and enforce certain minimum building and land use standards designed to reduce property damage from flooding. These regulations, among other things, require new or substantially remodeled structures within special flood hazard areas to be engineered and/or elevated in order to withstand anticipated flood conditions. They also require communities to prohibit development in floodways-areas that allow flood waters to discharge from special flood hazard areas. NFIP also shifts the cost of flood damage from taxpayers, who ultimately pay for disaster relief, to property owners through flood insurance premiums. The risk of flood damage to the structure's lowest floor from a "100 year flood" provides the basis for National Flood Insurance Program premiums. Flood Insurance Rate Maps-also based on the "100-year" flood line-delineate special hazard areas and applicable risk premium zones (Appendix One). These Federal Emergency Management Agency generated maps serve as primary reference documents for the National Flood Insurance Program and other flood-related policies and programs at all levels of government. New National Flood Insurance Program Regulations and Requirements for Participation The Community Development and Regulatory Improvement Act was signed into law in 1994. This Act amended the enabling National Flood Insurance Program (NFIP) legislation in order to reduce federal spending on flood losses and to improve the financial status of NFIP. To this end, it directs federal loan agencies and federally regulated or insured lending institutions to "require flood insurance when making, increasing, extending, or renewing loans and to maintain the coverage for the life of the loan" for all homes in special flood hazard areas. The Act also authorizes: (1) mitigation assistance grants for states and communities to protect homes and businesses; and (2) mitigation insurance for rebuilding to meet improved design and construction standards. In 1994, new National Flood Insurance Program (NFIP) regulations were also promulgated to require all property owners (including those in high-rise condominiums) in "special flood hazard areas" - as determined by the community's Flood Insurance Rate Map-to insure their properties against flood damage equal to 80% of replacement value. Changes in NFIP regulations since 1994 have required additional homeowners in Hawaii to buy flood insurance. As a result, the number of Hawaii's NFIP policies more than doubled over an eighteen month period. In December 1994, there were 22,140 flood insurance policies statewide. By July 1996, the number of policies had increased to 47,801 (Table 1), giving Hawaii the largest per capita participation in the NFIP in the United States, and third highest number of policies overall. Over the same period, the value of NFIP policies in Hawaii increased from over $2.5 billion to over $5.7 billion. Table 1: Flood Insurance Trends in Kauai, 1993 to 1996
Although the number of policies increased dramatically, the face value of the average National Flood Insurance Program policy remained about the same and the average premium has declined. The mean value of flood policies in Hawaii increased from $120,897 in December 1994 to $121,332 in July 1996. Over the same period, the average cost of premiums decreased from $443 in 1994, $272 in 1995, and to $264 in 1996. The reductions in the average premiums probably reflect the large number of people outside the special flood hazard area who have purchased policies, as well as the increase in the number of condominium policies. The decrease in the average premium provides little solace to homeowners paying more for their property insurance. Most single-family dwelling owners in the special flood hazard area who had flood insurance in 1994 are probably paying about the same premium in 1996. However, more property owners are now required to buy flood insurance. The average condominium policy may be less expensive than a flood insurance policy for a single-family dwelling. However, the requirement that the value of "commercial" policies for condos in the special flood hazard area be equivalent to 80% of the replacement value has caused huge increases in costs for condominium associations. For example, flood insurance costs for one large condo in Honolulu increased from about $9,000 in 1994 to over $39,000 in 1995. This increase was passed directly on to individual homeowners through their maintenance fees. Flood Mitigation Activities on Kauai
EROSION (Up to TOC) Beach erosion and coastal erosion are not the same, but they are related. Beach erosion is a reduction in the amount of sand a particular beach has. On a global level, sea level rise causes beach erosion. But beaches also erode (and expand) on a seasonal basis. Beaches get sand from both the ocean and the land. Larger waves move sand from the coastal sand dunes off into the ocean. This raises the seafloor, flattens the overall profile of the beach, and, therefore, causes waves to break further offshore. This, in turn, minimizes the waves' impact on coastal lands. Beaches recover from these seasonal shifts when the waves move the sand back onto the beach and the winds blow the deposited sand into dunes. These dunes will store the land-based sand until the next large wave event. Coastal erosion occurs when the beach migrates toward the land in order to compensate for beach erosion as it tries to maintain a constant supply of sand (see the right side of the photo). If sand is not available to a beach, such as when a wall is built to protect the land, the land is stabilized, however beach erosion will occur (see left side of photo). Installing a seawall or revetment (i.e., hardening a shoreline) interferes with the natural cycle of beach erosion. Rather than pulling sand from a landward supply in order to promote waves breaking further off-shore during the seasonal high wave period, the seawall or revetment prevents this natural phenomena from occurring. Thus, the land itself begins to erode. Therefore, it is tragically ironic seawalls or revetments have been installed to prevent coastal erosion, but their very presence exacerbates the very problem they were supposed to resolve. Erosion is caused by:
What are my risks? On Kauai, short sections of populated coast have undergone extensive hardening and chronic erosion. As much as 1 to 2 miles of beach degradation has occurred there. Beach loss affects Hawaii residents by seriously impacting the visitor economy. In 1997, tourism accounted for 171,900 jobs in the state, $13 billion in tourism expenditures and supported a payroll of $3.5 billion. Beach loss and shoreline hardening restricts public access to ocean recreation areas and natural resources. It causes environmental and ecological damage to natural resources and habitats. Coastal hardening can also produce coastal water quality problems through increased turbulence and turbidity. SOURCE: SOEST, Coastal Erosion Management Plan. 1998.
The full document can be reviewed at your regional public library. Coastal Erosion Mitigation Options for Agencies Revise the Shoreline Setbacks The intent of shoreline setbacks is to establish a coastal-hazard buffer zone to protect beach-front development from coastal erosion. Adequate setbacks allow the natural erosion and accretion cycles to occur and help maintain lateral beach access. Furthermore, setbacks provide open space for the enjoyment of the natural shoreline environment. A 40-foot shoreline setback has been often inadequate because they are not determined by historical site-specific rates of coastal erosion. Coastal-erosion hazard maps could be used to establish rate-based building setbacks. Setbacks would be site-specific in order to reflect the nature of coastal erosion. These setbacks would also incorporate the proposed style of development. Construction-style considerations would include the size and expected lifetime of the planned structure. Larger, immovable buildings and those with lifetimes of more than 50 years would have deeper setbacks than small, movable structures. Conduct Beach nourishment This is a technique used to restore an eroding or lost beach or to create a new sandy shoreline, involves the placement of sand fill with or without supporting structures along the shoreline to widen the beach. It is the only management tool that serves the dual purpose of protecting coastal lands and preserving beach resources. Beach nourishment requires large volumes of beach-quality sand. The initial nourishment project typically requires thousands of cubic meters of sand per kilometer of shoreline, and most beaches need periodic re-nourishment. Preserve Sand Dunes Sand dunes trap windblown sand, store excess beach sand, and serve as natural erosion buffers. Therefore, preserving and restoring sand dunes would protect beachfront property and coastal infrastructure during storms and high-wave events. Healthy dunes are vegetated by salt-tolerant species with a dense root system, making them effective wind-breaks and wave buffers. Utilize Inter-agency communication Better cooperation between State Parks and the Counties' Parks and Recreation should be sought since these departments maintain many of our beach parks. In addition, discussions should be enhanced with the State Department of Transportation (DOT), because some highway facilities are threatened or will soon be threatened by coastal erosion. In most cases, state highway facilities are the major or only thoroughfare between regions. Proactive planning of new highway construction, widening, and realignment could reduce the threat of coastal erosion and beach loss by anticipating future shoreline trends. Increase Public Awareness Coastal erosion is largely promulgated by the activities of humankind. Increasing public awareness of the importance of seasonal beach erosion, and how their activities can exacerbate coastal erosion, becomes extremely important. Promote Research Projects Projects that focus on coastal processes can lead to improved erosion management. Further research, along with beach monitoring, is necessary to increase our understanding of coastal and marine science and to insure effective and efficient management of the coastal zone. Conduct Land Banking Acquiring and holding land threatened from coastal erosion for a future use may be in the best public interest. This funding mechanism, falling outside of the normal process of budget appropriations, provides a way to regularly set aside funds for land acquisitions in both good and bad economic times. Coastal Erosion Mitigation Activities on Kauai The following is a list of agencies and programs in Hawaii that are taking
steps to mitigate coastal erosion.
Coastal Erosion Mitigation at Home Support Shoreline Setbacks The intent of shoreline setbacks is to establish a coastal-hazard buffer zone to protect beach-front development from coastal erosion. Adequate setbacks allow the natural erosion and accretion cycles to occur and help maintain lateral beach access. Furthermore, setbacks provide open space for the enjoyment of the natural shoreline environment. A 40-foot shoreline setback has been often inadequate because they are
not determined by historical site-specific rates of coastal erosion. Coastal-erosion
hazard maps could be used to establish rate-based building setbacks. Setbacks
would be site-specific in order to reflect the nature of coastal erosion.
These setbacks would also incorporate the proposed style of development.
Construction-style considerations would include the size and expected
lifetime of the planned structure. Larger, immovable buildings and those
with lifetimes of more than 50 years would have deeper setbacks than small,
movable structures. Encourage Beach Nourishment Beach nourishment is a technique used to restore an eroding or lost beach or to create a new sandy shoreline It involves the placement of sand fill with or without supporting structures along the shoreline to widen the beach. It is the only management tool that serves the dual purpose of protecting coastal lands and preserving beach resources. Some homeowners associations on Maui have implemented small-scale, privately-funded
successful beach nourishment projects. Homeowners interested in learning
more about beach nourishment should contact the State Department of Land
and Natural Resource, Coastal Lands Program at (808) 587-0446. Develop and Install Best Management Practices When coastal erosion threatens property, coastal landowners are usually unaware of the different types of coastal protection measures that are available and the applicable environmental concerns and permitting requirements. Conventional coastal protection structures (i.e., seawalls and revetments) cause beach narrowing and loss. Instead (for example) the use of sand bags and large sand-filled geotextile tubes ("sea bags") will temporarily control coastal erosion. Another example may be concave or "V" shaped structural hardening designs that may retain sand better than linear structures. In addition, developers and landowners should consult with various experts and governmental agencies, such as the Department of Land and Natural Resources, Coastal Lands Program at (808) 585-0446. These agencies are familiar with coastal erosion in order to get appropriate recommendations on project design. Comply with Building Codes and Land Use Regulations During the planning phase, the applicant should incorporate the advice of the County Planning Department (808) 241-6677, comply with building codes and land use regulations to decrease the risk of coastal hazards. Developers and landowners should also acknowledge developments along the shoreline are subject to the risk of coastal erosion and any request to protect structures and property with shoreline armoring is currently discretionary. What can I do at work? Controlling beach erosion will help protect waterfront property, preserve species which live on the coastline and prevent a loss of tourism. While natural factors and rising sea levels account for some of the loss, human factors -- such as developing too close to the coastline and building sea walls -- play a significant part. It is estimates that 43% of businesses never reopen following a local
disaster, such as a coastal erosion. It is important that business owners
take proactive steps to protect their business, because they are a vital
part of the community. Mitigation activities for business owners are similar
to the activities for homeowners. Support Shoreline Setbacks. The intent of shoreline setbacks is to establish a coastal-hazard buffer zone to protect beach-front development from coastal erosion. Adequate setbacks allow the natural erosion and accretion cycles to occur and help maintain lateral beach access. Furthermore, setbacks provide open space for the enjoyment of the natural shoreline environment. A 40-foot shoreline setback has been often inadequate because they are
not determined by historical site-specific rates of coastal erosion. Coastal-erosion
hazard maps could be used to establish rate-based building setbacks. Setbacks
would be site-specific in order to reflect the nature of coastal erosion.
These setbacks would also incorporate the proposed style of development.
Construction-style considerations would include the size and expected
lifetime of the planned structure. Larger, immovable buildings and those
with lifetimes of more than 50 years would have deeper setbacks than small,
movable structures. To support increasing shoreline setbacks on Kauai contact the Planning
Department at 241-6677. Encourage Beach Nourishment. Beach nourishment is a technique used to restore an eroding or lost beach or to create a new sandy shoreline It involves the placement of sand fill with or without supporting structures along the shoreline to widen the beach. It is the only management tool that serves the dual purpose of protecting coastal lands and preserving beach resources. Some homeowners associations on Maui have implemented small-scale, privately-funded successful beach nourishment projects. Business owners interested in learning more about beach nourishment should contact the State Department of Land and Natural Resource, Coastal Lands Program at (808) 587-0446. Develop and Install Best Management Practices. When coastal erosion threatens property, coastal landowners are usually unaware of the different types of coastal protection measures that are available and the applicable environmental concerns and permitting requirements. Conventional coastal protection structures (i.e., seawalls and revetments) cause beach narrowing and loss. Instead (for example) the use of sand bags and large sand-filled geotextile tubes ("sea bags") will temporarily control coastal erosion. Another example may be concave or "V" shaped structural hardening designs that may retain sand better than linear structures. In addition, developers and landowners should consult with various experts and governmental agencies, such as the Department of Land and Natural Resources, Coastal Lands Program at (808) 585-0446. These agencies are familiar with coastal erosion in order to get appropriate recommendations on project design. Comply with Building Codes and Land Use Regulations. During the planning phase, the applicant should incorporate the advice of the County Planning Department (808) 241-6677, comply with building codes and land use regulations to decrease the risk of coastal hazards. Developers and landowners should also acknowledge developments along the shoreline are subject to the risk of coastal erosion and any request to protect structures and property with shoreline armoring is currently discretionary. LANDSLIDES (Up to TOC) What causes a landslide? A "landslide" happens when gravity forces land downward, often due to too much or lack of precipitation, runoff, or ground saturation. The wetting and drying of the uppermost ground material results in alternate expansion and contraction with gravity pulling the contracting Earth downward. The term includes mudslides, debris flow, debris avalanches, rock falls, and rock slides. Landslides usually occur with another natural hazard, such as an earthquake or flooding. What are a landslide's effects? Public and private economic losses from landslides include replacing and repairing damaged facilities, loss of productivity, disruption of utility and transportation systems, and reduction in property values. A severe landslide can cause great financial hardship to a property owner because many do not obtain earthquake insurance. SOURCE: State of California Department of Conservation, Sacramento, CA and National Landslide Information Center, U.S. Geological Survey, Denver, CO What areas are prone to landslides? Areas generally more prone to landslides are those located at:
SOURCE: State of California Department of Conservation,
Sacramento, CA and National Landslide Information Center, U.S. Geological
Survey, Denver, CO
Become familiar with the land around you. Learn whether debris flows have occurred in your area by contacting local officials, State geological surveys or departments of natural resources, and university departments of geology. Slopes where debris flows have occurred in the past are likely to experience them in the future. Watch the patterns of storm-water drainage on slopes near your home, and note especially the places where runoff water converges, increasing flow over soil-covered slopes. Watch the hillsides around your home for any signs of land movement, such as small landslides or debris flows or progressively tilting trees. Watch the patterns of storm-water drainage on slopes near your home, and note especially the places where runoff water converges, increasing flow over soil-covered slopes. Watch the hillsides around your home for any signs of land movement, such as small landslides or debris flows or progressively tilting trees. Purchase earthquake insurance. Homeowner's insurance does NOT cover losses due to landslide. Conduct a detailed site analysis. Private consulting companies may be hired to produce a landslide vulnerability map for your home, as well as to recommend mitigative practices. Install and maintain structures. Proper engineering, site selection, installation, and maintenance of structures (e.g., gabions) to improve drainage conditions and increase slope stability can assist in mitigating the effects of a landslide. Remember: If you build walls to divert debris flow and the flow lands on a neighbor's property, you may be liable for damages. Plant ground cover on slopes. The roots of plants can help secure dirt to the slope. Support your local government in efforts to develop and enforce land-use and building ordinances that regulate construction in areas susceptible to landslides and debris flows. Buildings should be located away from steep slopes, streams and rivers, intermittent-stream channels, and the mouths of mountain channels. What can I do at work? Although the physical cause of many landslides cannot be removed, geologic investigations, good engineering practices, and effective enforcement of land-use management regulations can reduce landslide hazards. USGS scientists continue to produce landslide susceptibility maps for many areas in the United States. USGS and DLNR hydrologists with expertise in debris and mud flows are studying landslide hazard.
TSUNAMIS (Up to TOC) What are Tsunamis? Tsunamis are NOT surfing waves!!! Never
attempt to surf or ride a tsunami! Although a deadly tsunami wave
may have the same height as a surfing wave, its characteristic is turbulent,
unpredictable, powerful, rubble filled, and deadly. A tsunami is series
of waves powerful enough to move house-sized boulders weighing many tons.
A tsunami is a series of great waves most commonly caused by violent
movement of the sea floor - usually an earthquake. Tsunamis are also caused
by nearshore or underwater landslides, or volcanic eruptions. This differs
from regular ocean waves that are generated from the wind. Tsunamis are
characterized by great speed (up to 590 mph), long wave length (up to
120 miles), long period between successive crests (varying from 5 minutes
to a few hours, generally 10 to 60 minutes), and low height in the open
sea. Often the first wave of a tsunami may not be the largest. The danger
from a tsunami can last for several hours after the arrival of the first
wave. Sometimes a tsunami causes the water near the shore to recede, exposing
the ocean floor. Tsunami can be very large. In coastal areas their height
can be as great as 30 feet or more (100 feet in extreme cases), and they
can move inland several hundred feet. Tsunami can travel up rivers and
streams that lead to the ocean. Kauai has had a tsunami?! A tsunami's effect at the shoreline can be considerably different within very short distances. The only general rule is that runup heights tend to be greatest near where the offshore bathymetry is steeper. Along gentle-sloping coasts, wave energy is dissipated upon shoaling. Even so, inundation can be significant and is usually greatest along low-lying coastal plains. An important historical example that demonstrates the variability of tsunami impact at the shoreline occurred during the 1965 tsunami on the north shore of Kauai. Despite the same north-facing exposure at Haena and Hanalei, a runup height of 35 feet was recorded at Haena, while only a few miles away in Hanalei Bay, runup was a mere 3 feet. In some cases, the runup height has been nearly equal on opposite sides of the island, suggesting that shoreline orientation (i.e. facing the tsunami source) is not always an important control. For example, during the 1960 tsunami, generated by an earthquake in Chile far to the southeast, a runup of 13 feet was recorded at Haena, only 1 foot lower than the maximum of 14 feet for the entire island reported at Hanapepe. Despite these variations, each side of Kauai has observed tsunami runups of over 10 feet with significant damaging effects. Written history records a tsunami damaging Kauai once every 16.5 years. However, the last of these tsunamis occurred in 1965, so looking at the time period between 1933 and 1965, the average recurrence interval was ~4.5 years. In light of the long-term frequency with which tsunamis have adversely impacted Kauai (i.e., every 16.5 years), one might conclude a damaging tsunami is overdue. Tsunami Mitigation Activities in Kauai County
Mitigation Activities At Home To mitigate any rapid onset natural disaster, it is critical to accurately assess the nature of the hazard, design an alerting technique, and prepare the at-risk area for appropriate reaction to reduce the impact of the hazard. These three components must be highly interactive and well coordinated to mitigate the effects of a tsunami. Thus, a coordinating body of appropriate scientists, emergency managers, emergency planners, and warning center operators, with representations from each affected state, should be created to ensure this coordination. The best mitigation activities a homeowner can do is to support the development of inundation maps, the installation of deep-water tsunami warning buoys, the placement of tsunami hazard signage and sirens, and the implementation of coastal setbacks and regulatory programs. What can I do at work? It is estimated that 43% of businesses never reopen following a local disaster, such as a tsunami. Therefore, it is important business owners take proactive steps to protect their business, because they are a vital part of the community. The Small Business Administration (SBA) and the Institute for Business & Home Safety (IBHS) suggest that small business owners develop a Disaster Plan that includes mitigation activities. These activities are divided into the following categories:
Facilities (Buildings & Equipment)
Operations
Critical Information and Communication
Insurance
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