Malibu Municipal Code Ch. 4 Hazards & Shoreline/Bluff Development

A. Introduction

The City of Malibu lies at the junction of the Santa Monica Mountains and the Pacific Ocean. Development within the City, including roads and other infrastructure is highly vulnerable to a variety of natural hazards including threats from landslides, wild fires, earthquakes, storm waves, and flooding. Bluffs, beaches, and steep hillsides are subject to natural erosional forces, often accelerated by the effects of fires, torrential rains, and winter storms. Fire is a serious potential threat several months of every year due to the typically long summer dry season characteristic of the Mediterranean climate and periodic “El Nino” winter storm seasons which cause considerable destruction or severe damage to beachfront homes, widespread erosion along the shoreline and bluffs, and landslides that destroy or damage homes, septic systems and roads, including Pacific Coast Highway. Occasionally, a severe fire season is followed by a winter of high rainfall, leading to extraordinary erosion and landslides on hillside property which had been denuded of vegetation by the fire. The dependence on septic systems for waste disposal throughout the City, with minor exceptions, creates additional hazards due to the effect of poorly maintained or located systems on steep slopes and beaches, the aforementioned erosional forces and a high water table in many areas.

The Malibu shoreline consists of a series of rocky headlands and narrow crescent shaped beaches, vulnerable to erosion and wave uprush. Unlike many other coastal communities in the State, a large portion of the beachfront property in Malibu was subdivided and developed prior to 1976, before the effective date of the Coastal Act. Most of this development occurred without the benefit of planning or mitigation to minimize impacts from wave hazards and to coastal resources. Largely as a result of the pre-existing pattern of development in Malibu, development along the shoreline continues to be permitted, placing more property at risk. To reduce the risk to private beachfront development, armoring of the shoreline has often occurred in the form of vertical seawall and rock revetments. Many of these structures have been placed on the beach as emergency actions during or immediately following winter storms, often without permits or adequate planning relative to placement, design, and impacts to adjacent properties and shoreline processes and public recreation. Loss of beach and, therefore, public access is too often the result of the construction of protective structures such as seawalls and revetments.

The cumulative loss of shoreline and public recreational resources from the encroachment of armoring on sandy beaches is an important coastal management issue. The City lies within the Santa Monica Littoral cell. The major sediment source has historically been the streams draining the Santa Monica Mountains. The sediment from much of the drainage area, however, has been trapped behind dams and catchment basins, never reaching the coast (USACOE). Another significant sediment source has been the incremental addition of eroded material from coastal bluffs. In addition to covering beach area that provides for recreation, however, shoreline armoring also can exacerbate erosion by fixing the back beach and eliminating the influx of sediment from coastal bluffs. The City has found that over 60 percent of the bluffs are blocked from the erosive forces of wave action by some form of development, including Pacific Coast Highway, vertical seawalls and revetments. Armoring also causes localized scour in front or at the end of the seawall or revetment. In addition, by allowing shoreline armoring in areas with existing development, the cycle of rebuilding storm damaged or destroyed development in the same hazardous areas is often perpetuated. From 1978 through 1996, the Coastal Commission and the County or City authorized protective devices along an estimated 2.8 miles of shoreline, covering an estimated 3.5 acres of sandy beach (ReCAP, 1999). The ReCAP report found that when added to the amount of shoreline armored prior to 1978, determined by Coastal Commission analysis of aerial photos, and the armoring which has taken place without permits, a total of approximately 50 percent of the City’s shoreline has been impacted by shoreline protective structures. The report concluded that unless future armoring is avoided, future buildout of shoreline lots could result in up to 5 miles of additional shoreline armoring with hard structures. Additional armoring is even more likely given the location of Pacific Coast Highway (PCH). PCH continues to be threatened by erosion, wave uprush and flooding wherever it is located adjacent to the ocean, and given its importance to regional access and transportation, it is possible it will be armored throughout most of its length in the City unless alternative means of protection are developed.

1. Coastal Act Provisions. Under the Coastal Act, development is required to be sited and designed to minimize risks, assure stability and structural integrity, and neither create nor contribute significantly to erosion or require the construction of protective devices that would substantially alter the natural landforms along bluffs and cliffs (Section 30253). Section 30235 of the Coastal Act allows the construction of shoreline protective devices where existing development is threatened from erosion and when designed to eliminate or mitigate impacts on shoreline sand supply. The Coastal Act also provides that development damaged or destroyed by natural disasters can be rebuilt in the same location, exempt from a coastal development permit, under certain conditions. Certain emergency actions are also exempt from permit requirements.

2. Land Use Plan Provisions. To ensure consistency with the Coastal Act, the policies contained below in the Land Use Plan are intended to facilitate development in a manner which minimizes impacts from hazards as well as impacts to coastal resources, including public access and recreation. These policies can be summarized as follows:

B. Coastal Act Policies. The Coastal Act Policies set forth below are incorporated herein as policies of the Land Use Plan:

Section 30235. Revetments, breakwaters, groins, harbor channels, seawalls, cliff retaining walls, and other such construction that alters natural shoreline processes shall be permitted when required to serve coastal-dependent uses or to protect existing structures or public beaches in danger from erosion, and when designed to eliminate or mitigate adverse impacts on local shoreline sand supply. Existing marine structures causing water stagnation contributing to pollution problems and fish kills should be phased out or upgraded where feasible.

Section 30253. New development shall:

(1) Minimize risks to life and property in areas of high geologic, flood, and fire hazard.

(2) Assure stability and structural integrity, and neither create nor contribute significantly to erosion, geologic instability, or destruction of the site or surrounding area or in any way require the construction of protective devices that would substantially alter natural landforms along bluffs and cliffs.

(3) Be consistent with requirements imposed by an air pollution control district or the State Air Resources Control Board as to each particular development.

(4) Minimize energy consumption and vehicle miles traveled.

(5) Where appropriate, protect special communities and neighborhoods which, because of their unique characteristics, are popular visitor destination points for recreational uses.

C. Land Use Plan Policies

a. Low Slope Stability & Landslide/Rockfall Potential: hillside areas that have the potential to slide, fail, or collapse.

b. Fault Rupture: the Malibu Coast-Santa Monica Fault Zone.

c. Seismic Ground Shaking: shaking induced by seismic waves traveling through an area as a result of an earthquake on a regional geologic fault.

d. Floodprone areas most likely to flood during major storms.

e. Liquefaction: areas where water-saturated materials (including soil, sediment, and certain types of volcanic deposits) can potentially lose strength and fail during strong ground shaking.

f. Liquefaction/Floodprone areas where saturated sediments lie in flood plains.

g. Tsunami: shoreline areas subject to inundation by a sea wave generated by local or distant earthquake, submarine landslide, subsidence, or volcanic eruption.

h. Wave Action: shoreline areas subject to damage from wave activity during storms.

i. Fire Hazard: areas subject to major wildfires classified in Fire Zone 4 or in the Very High Fire Hazard Severity Zone.

4.15 Existing, lawfully established structures, which do not conform to the provisions of the LCP, may be maintained and/or repaired provided that such repair and maintenance do not increase the extent of nonconformity of the structure. Except as provided below, additions and improvements to such structures may be permitted provided that such additions or improvements comply with the current standards and policies of the LCP and do not increase the extent of nonconformity of the structure. Substantial additions, demolition and reconstruction, that result in demolition and/or replacement of more than 50% of the exterior walls shall not be permitted unless such structures are brought into conformance with the policies and standards of the LCP.

a. The profile of the beach;

b. Surveyed locations of mean high tide lines acceptable to the State Lands Commission;

c. The availability of public access to the beach;

d. The area of the project site subject to design wave uprush;

e. Foundation design requirements;

f. The need for a shoreline protection structure over the life of the project;

g. Alternatives for protection of the septic system;

h. The long term effects of proposed development on sand supply;

i. Future projections in sea level rise; and

j. Project alternatives designed to avoid or minimize impacts to public access.

a. An examination of local and regional annual erosion rates in order to reflect current shoreline changes.

b. Standard engineering plans and analyses defining the specific types of armoring that would be acceptable or preferable for specific areas, and where appropriate, identification of the types of armoring that should not be considered for certain areas or beaches in order to minimize risks and impacts from armoring to public access and scenic resources along the shoreline and beach recreation areas.

c. Standard alternatives feasibility analysis that would be a required element of all hazard response projects and that would require applicants to go through a series of steps to assure that hard protective devices were only used as a last resort. The analysis should require, but not be limited to, the use of technical evaluations of the site (geotechnical reports, engineering geology reports, wave uprush reports etc.), an examination of all other options (removal, relocation, sand replenishment, no action etc.), and a conclusion that a shoreline protective device would be the “best option” (most protective of the public trust, best long term solution etc.) for the subject site.

d. Standard conditions and monitoring requirements that should include mechanisms to ensure shoreline protection effectiveness and public safety with provisions for the removal or ineffective or hazardous protective structures as well as programs to address beach replenishment and sand supply.

e. Procedures to address emergency armoring, such as: coordination with property owners and for field inspections before and after storm seasons; guidance for types of temporary protective structures preferred and a provision for removal of temporary structures if no follow up permit is filed.

f. Shoreline Management Plans developed pursuant to the above stated standards shall not be effective until they have been certified by the Coastal Commission as an amendment to the LCP.

a. No stockpiling of dirt or construction materials shall occur on the beach;

b. All grading shall be properly covered and sandbags and/or ditches shall be used to prevent runoff and siltation;

c. Measures to control erosion shall be implemented at the end of each day’s work;

d. No machinery shall be allowed in the intertidal zone at any time to the extent feasible;

e. All construction debris shall be removed from the beach.

a. Assessing site-specific characteristics such as topography, slope, vegetation type, wind patterns etc.;

b. Siting and designing development to avoid hazardous locations;

c. Incorporation of fuel modification and brush clearance techniques in accordance with applicable fire safety requirements and carried out in a manner which reduces impacts to environmentally sensitive habitat to the maximum feasible extent;

d. Use of appropriate building materials and design features to insure the minimum amount of required fuel modification;

e. Use of fire-retardant, native plant species in landscaping.