March 1994
This report was prepared by the staff of the California Coastal Commission as part of a Project of Special Merit for the Office of Coastal Resource Management, National Oceanic and Atmospheric Administration. It has not been approved by the Commission.
Additional Documents prepared by the Commision staff under this Project of Special Merit include:
1. Permitting Process for Projects Involving Land Form Alteration
A. Coastal Act and CEQA Review
B. Grading Projects Not
Requiring a Local Government CDP
2. Filing Requirements for a CDP
1. Introduction
A. The LCP must insure thorough review of all projects for land form
alteration concerns
2. Contents of LCP-LUP Policies and IP Ordinances
A. LCP policies address land form alteration in many different ways
B. LCP policies should state what is meant by "minimizing land form
alteration"
C. Criteria should be established for both grading and
site disturbance
3. Concentration of Development
A. Development densities must match the capacity of the land form
B. Lot development limitations based on slope
C. The LCP should remove
barriers to concentrated development
4. Grading and Erosion Impacts
A. Acceptable land form alteration may vary for different land types or
locations
B. Erosion and sedimentation plans should be required for steep
slopes
C. No grading should be allowed during the rainy season
D.
Buffers and setbacks can protect from the erosion impacts of land form
alteration
5. Alternatives to Development
A. Transfer of Development Credit Programs can help reduce land form
alteration
B. LCPs should set up a program to retire the development
potential of targeted lots
6. LCP Implementation and Enforcement
A. Implementation of all land form alteration policies must be assured
B. Possible pitfalls to thorough implementation of LCP land form
policies
C. Land form alteration policies must be enforced
1. Introduction
A. Planning decisions can set in motion eventual massive land form
impacts
2. Subdivision Concerns
A. Some areas should never be subdivided
B. Characteristics of a
good parcel for subdivision approval
3. Site Assessment of Resources and Impacts
A. No subdivision should be approved without complete information on
impacts
B. All resources on the parcel must be thoroughly identified and
mapped
C. Drainage characteristics of the parcel must be studied
D.
Site topography and geologic hazards must be studied thoroughly
E. Developable areas should be identified from resource and hazards maps
4. Site Access
A. Site access must be provided in detail
B. Access must be
reviewed relative to site drainage
C. Only areas with safe access should be
considered for development in subdivision plans
5. Geologic Hazards
A. In most cases, a geotechnical or soils engineer should do early site
review
B. Site stabilization will change existing land forms; site geology
must be studied
C. Plans for a subdivision with slope stabilization
D.
Planning alternatives for slope stabilization
E. Subdivision plans for
areas on or adjacent to active faults
F. Intent of the Alquist-Priolo Act
G. Subdivision of Eroding Parcels
6. Necessary Submittal Contents
A. All technical reports must be clear and precise
B. A
subdivision plan, complete with all relevant requirements, must be provided
C. Subdivision plans should specify appropriate foundation styles for building
pads
7. Summary/Public Handout
A. TABLE 1 Types of Information for Subdivision Planning Decisions
B. Summary of Subdivision and Site Planning Goals
1. Introduction
A. Thoroughness with a subdivision plan can help lot development review
2. Lot Development Criteria
A. Lot development should address all the concerns discussed for
subdivisions
B. Lot development options must establish the least damaging
alternative
C. Site layout options can make a difference in resource impacts
3. Resource Impacts
A. Yard setbacks should not cause resource impacts
B. Resource
impacts may have to occur to establish a buildable area
C. All options must
be provided to the reviewing planners
4. Site Access
A. Goals of an access plan
B. Access should fit into the existing
land form
C. Access should complement efforts to protect or control
drainage
D. Access for fire equipment or other safety vehicles
E. Many road
standards can be negotiated
5. Site Stability
A. Goals for site stability
B. Maintenance of stabilization must
be considered
C. Keep drainage away from landslide prone areas and
engineered slopes
D. Engineers can often design slope stabilization to fit
planning criteria
6. Building Pad Constraints
A. Goals for a building foundation
B. Building foundations must
consider the hazards and resources of a site
C. The size of the buildable
area should equal or exceed the size of the building pad
D. Developable
lots cannot always accommodate extensive development
1. Introduction
2. Parcel Bisected by a Lagoon
A. Key features to consider in lot layout plans
B. Alternative 1
-- Conventional Lot Layout
C. Alternative 2 -- Modified Lot Layout
D.
Alternative 3 -- Lot Layout with Lot Line Adjustments
3. Parcel on Sand Dunes
A. Key features to consider in lot layout plans
B. Alternative 1
-- Conventional Lot Layout
C. Alternative 2 -- Modified Lot Layout
D.
Alternative 3 -- Lot Layout with Lot Line Adjustments
4. Parcel on Ridge Top with Steep Slope
A. Key features to consider in lot layout plans
B. Alternative 1
-- Conventional Lot Layout
C. Alternative 2 -- Modified Lot Layout
D.
Alternative 3 -- Lot Layout with Lot Line Adjustment
1. Access for Emergency Vehicles
A. Two-lane Access Road
B. Split Level Access Road
C. Single
Lane with Pullouts
2. Access Across Streams
A. Bridge
B. Culvert under Road
C. Arizona Crossing/Ford
3. Landslides or Slope Stability
A. Conventional Buttress Fill Slope
B. Contour Graded Slope
C. Steep Geogrid Slope
D. High Retaining Wall
E. Several Low Retaining
Walls
F. Gravity Wall/Crib Wall
1. Introduction
2. Building Foundations
A. Slab-on Grade Foundation
B. Pier or Caisson Foundation
C.
Terraced or Multi-Level Foundation
1. References or Review Material for Subdivision Plans
2. References or Review Material for Access Planning Decisions
3. References or Review Material for Site Stability Decisions
4. References or Review Material on Foundation Planning
General Guide to the Reader This document goes through most of the key land development steps, from the development of a Local Coastal Program to individual site designs. It shows how different subdivision choices can affect land form alteration, and shows different access designs, stream crossings, slope stabilization efforts, lot layouts and foundation designs which may provide opportunities to reduce the impacts from site development. In addition, it briefly discusses site access, site stability and development. Due to the breadth of issues that are covered, readers should refer to the Table of Contents to find the sections which address their concerns.
Concerns of Commission staff planners and local government planners are addressed throughout the document; project applicants and developers may be most interested in the following:
Section II, Coastal Commission Authority With Regard to Land Form Alteration;
Section IV (7), Types of Information for Subdivision Planning Decisions and Summary of Subdivision Goals;
Sections VI through VIII which provide general examples for subdivisions, access and stability, and site development; and,
Section IX, which lists references and additional review material.
Finally, if there are questions about land form impacts from a specific project and ways to minimize these impacts, the applicant should contact the appropriate planning staff as early in the planning process as is possible.
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