Geologic Hazard Abatement Districts
(From the July 1986 Issue of CALIFORNIA GEOLOGY
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
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
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.
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
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,
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.
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
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.
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.
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