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Geologic Hazard Abatement Districts

(From the July 1986 Issue of CALIFORNIA GEOLOGY magazine)

by Robert B. Olshansky

[Editor's note: At the time Robert Olshansky wrote this article, he was an employee of Rogers/Pacific; he currently (March 2000) is an Associate Professor of Urban and Regional Planning at University of Illinois and can be reached at robo@staff.uiuc.edu.] 
Original reference: Olshansky, Robert B., 1986, Geologic Hazard Abatement Districts: CALIFORNIA GEOLOGY, v. 39, n. 7, p. 158-159.

Geologic Hazard Abatement Districts (GHAD) enabled by the Beverly Act of 1979 (SB 1195), are potentially useful financial mechanisms for reducing hillslope hazards (Kockelman, 1986). The enabling statute, (Division 17 of the Public Resources Code, Sections 26500 - 26654) provides for the formation of local assessment districts for the purpose of prevention, mitigation, abatement, or control of geologic hazards. The Act broadly defines "geologic hazard" as "an actual or threatened landslide, land subsidence, soil erosion, earthquake, or any other natural or unnatural movement of land or earth."

 

 

 

 

 


Abalone Cove landslide, Rancho Palos Verdes, Los Angeles County. The toe of the landslide is at the shoreline. The Abalone Cove Landslide Abatement District was formed in January 1981, and was the first district formed after the Beverly Act of 1979. Photo by Martin L. Stout.

A GHAD may be proposed by one of two means: (1) a petition signed by owners of at least 10 percent of the real property in the district, or (2) by resolution of a local legislative body.

PLAN OF CONTROL

A proposal for a GHAD must be accompanied by a "plan of control", prepared by a certified engineering geologist, "which describes in detail a geologic hazard, its location and the area affected thereby, and a plan for the prevention, mitigation, abatement, or control thereof" (Section 26509). The land within a district need not be contiguous; the only requirement is that lands within a GHAD be specially benefited by the proposed construction and that formation of a district is required to ensure the health, safety, and welfare of the residents.

LOCAL DISTRICT ORGANIZATION

The Act requires public hearings prior to district formation. If owners of more than 50 percent of the assessed valuation of the proposed district object to the formation, the legislative body must abandon the proceedings. If there are few objections, the legislative body may form the district, initially appointing five property owners to the board of directors. Thereafter, the district becomes an independent entity with an elected board of directors. A GHAD may issue bonds, purchase and dispose of property, acquire property by eminent domain, levy and collect assessments, sue and be sued, and construct and maintain improvements.

First GHAD

The Beverly Act was originally drafted to allow for the formation of the Abalone Cove Landslide Abatement District in Rancho Palos Verdes, Los Angeles County. The 600-acre Abalone Cove landslide, which began moving in 1978, threatened over 100 homes upon and adjacent to it. It is located immediately west of the well known Portuguese Bend landslide, and probably has a similar mechanism (movement along seaward-dipping bentonitic tuff beds) (Ehlig, 1979).

The district was formed in January 1981 and has financed continued geologic investigation of the slide and installation of mine dewatering wells (Heffler, 1981), which appear to have successfully reduced lateral movement. The Beverly Act provided a mechanism for the Abalone Cove home owners to jointly finance abatement measures. A significant point is that it allowed them to treat the landslide as a single physical entity, irrespective of property boundaries. A companion bill by Senator Beverly provided for liability exemption of local district for actions taken to abate gradual earth movements.

Other Districts

In the six years since enactment of the Beverly Act, not many Geologic Hazard Abatement Districts have formed, though a few have been proposed. A Plan of Control was prepared for a proposed GHAD at Mount Washington (City of Los Angeles) in 1981 (Lung, 1981), but the District was never formed because affected homeowners felt that they could not afford the remedial measures.

In 1982 a second GHAD was formed in Rancho Palos Verdes, encompassing the Klondike Canyon landslide, located immediately to the east of the Portuguese Bend slide (Ehlig, 1982). As with Abalone Cove, this GHAD was formed in order to finance continued investigation, monitoring, and dewatering measures.

Since 1984 the Blakemont Property Owners' Association in Kensington (western Contra Costa County) has been working on formation of a GHAD to include approximately 135 parcels covering 35 to 40 acres. This GHAD would cover an earthflow complex that has been periodically active over the years. During the 1960s an attempt was made to form a drainage improvement district, but this attempt failed. The present effort is in response to damage from January 1982. An engineering geologist is currently preparing a Plan of Control for the GHAD, jointly financed by the Association, public agencies, and a utility district.

The most recent GHAD was formed in June 1985 at Canyon Lakes, a subdivision of over 1000 acres near Danville in Contra Costa County. This District is different because it was formed prior to occupancy of the subdivision and there has not yet been active landsliding. The purpose of the District is to establish a mechanism to pay for regular maintenance of drainage systems, routine reconnaissance, and timely repairs of any slope failures. The subdivision will have several thousand owners when fully developed. The Plan of Control (Proctor, 1985) is a general document, describing the types of activities that the District might perform.

The Canyon Lakes GHAD initially appears to go beyond the original intent of the Beverly Act, which was designed to abate an immediate, existing hazard. However, the Act is ambiguous on this point. According to an informal opinion by the staff consultant to the State Senate Committee on Local Government (Detwiler, 1985) it is indeed possible, under the enabling legislation, to create a one landowner district in which the "threatened landslide" is an event which has a small, but finite, probability of occurring. Thus, it appears that a GHAD may serve a maintenance and prevention function as well as an abatement function. The Act is still unclear, however, regarding how detailed a Plan of Control for a maintenance-oriented district needs to be, and what the legal responsibilities of the initial owner-developer would be to future home owners. Clear guidance is still needed on how to equitably and effectively operate a prevention-oriented GHAD.

SUMMARY

The Geologic Hazard Abatement District is a potentially useful tool to effectively abate a landslide hazard that crosses property boundaries. It is a mechanism that responds to the physical realities of landslides, and allows property owners to cooperate in solving a common problem. It removes much of the stigma of legal liabilities among adjacent landowners and allows them to cooperate rather than litigate. It also provides for a cost-effective solution, requiring only one geotechnical engineering firm and one plan to solve the problems of several landowners. In short, as local communities become aware of the existence of this statute, it is likely that the GHAD, be it for repair of an existing landslide or prevention of an impending one, will become more commonly used throughout the state.

REFERENCES

  • Detwiler, P.M., 1985, Senate Committee on Local Government, letter to author regarding Geologic Hazard Abatement Districts (August, 1, 1985).

  • Ehlig, P.L., 1979, Final Report, Geotechnical investigation of Abalone Cove landslide, Rancho Palos Verdes, Los Angeles County, California: Robert Stone & Associates, Canoga Park, California, unpublished report, prepared for City of Rancho Palos Verdes, job no. 1372-00, doted February 28, 1979, 3 plates, 4 appendices, 54 p.

  • Ehlig, P.L., 1982, Results of subsurface geologic investigation-recommendations concerning Klondike Canyon landslide and moratorium boundary: Robert Stone & Associates, Canoga Pork, California, unpublished report prepared for City of Rancho Palos Verdes, job no. 1840-00, dated January 21, 1982, 3 plates, 14 p.

  • Heffler, R., 1981, State's first slide district forms: Los Angeles Times, January 8, 1981, p. IX-1.

  • Kockelmon, W.J., 1986, Some techniques of reducing landslide hazards: Bulletin of the Association of Engineering Geologists, v. 23, no. 1, p. 29-50.

  • Lung, Richard, 1981, Mount Washington Geologic Hazard Abatement District, Geotechnical Investigation Report: Leighton and Associates, Irvine, California, unpublished consulting report prepared for the Department of Building and Safety of the City of Los Angeles, report no. 1800632-01, dated July 15, 1981, 6 plates, 4 appendices, 36 p.

  • Proctor, R.J., 1985, Plan of control for Canyon Lakes Geologic Hazard Abatement District, Contra Costa County, May 2, 1985.