Thoroughness in subdivision plans can help lot development review If a subdivision plan has been carefully prepared and thoroughly reviewed for all land form alteration concerns, the review and approval of the subsequent development elements of the subdivision can usually be accomplished quickly. A subdivision plan which sites all development in areas without any critical resources, sensitive habitat or hazardous areas and which has addressed the land form alteration concerns of each subdivision element will facilitate all later reviews and permit analysis. Unfortunately, there are many legally approved subdivisions and existing lots of record which were created many years ago and did not undergo the scrutiny that they would receive today. It is safe to say that many of these subdivisions and lots of record would not be approved today; however, as legally created lots, usually they carry with them the right to be developed to, at least, the minimum development levels allowed in the land use plan.
2.A. Lot development should address all the concerns discussed for subdivisions Good lot development should be based on a detailed understanding of the physical characteristics and resources of the lot. If the subdivision effort was thoroughly reviewed, much of the information for lot development can be gleaned from the subdivision application effort. If the subdivision review was not thorough, the lot developer will have to undertake these studies independently, and may want to coordinate this effort with other property owners. Efforts to put together a safe, environmentally acceptable lot plan must include a review of site geology and potential hazards, surface drainage, streams, erosion and sedimentation characteristics, prominent features, vegetation and wildlife usage, archaeological resources, trails, viewing areas, and any other concerns which is significant in the region. As with the subdivision step, this information would be used to determine the locations of buildable areas that would neither require any site remediation for safety nor disturb or in any way harm any of the significant resources on the site.
2.B. Lot development options must establish the least damaging alternative Some lots may not have any buildable areas where development can occur without any adverse effects whatsoever. Since a legal lot carries with it a strong potential for some form of development, the developer must examine a number of options to minimize these adverse impacts. The developer must not confuse objective physical constraints, such as unstable soils or sensitive habitat with more flexible subjective constraints. If the developer has a pre-conceived idea of the development style, it can preclude consideration of acceptable alternatives for some physically-constrained sites.
2.C. Site layout options can make a difference in resource impacts Some sites may present so many constraints to site development or so broad a basis for concern that it may seem that all development options are equally harmful, and thus equally acceptable. This is rarely the case; developers may find the least damaging option immediately so that all the other options are comparable or worse, making the process of option examination seem futile. To illustrate this, several scenarios have been prepared for laying out lots in three small subdivisions (Section V.). The areas are around a lagoon, in a sand dune and on a steep ridge. None of these areas would be considered as acceptable subdivision areas if they were being reviewed today; nevertheless, such subdivisions do exist. The development layout options show the undeveloped lots and several development schemes. The first scheme shows little regard for either the hazards or resources on the sites, the second, takes the existing lot scheme to minimize the impacts and the third concentrates the same level of development into a cluster-type grouping to show the reduction in impacts which could occur with lot line adjustments. Again, for all of these examples, the parcel in question would not be considered acceptable for subdivision were it to be attempted today.
3.A. Yard setbacks should not be cause of resource impacts If the only buildable areas are precluded from development due to yard setback requirements, these requirements should be examined. Options for variances to these setbacks should be considered, and the possible resource damage should be weighted against the benefits provided by the regulated setback.
3.B. Resource impacts may have to occur to establish a buildable area Some lots may actually not have any buildable area or the buildable areas may be too small to accommodate any reasonably sized building. For these lots, the building size must be kept small, and the different siting options should be considered to minimize resource impacts. The maps of physical constraints and sensitive resources can be very useful for finding areas with the fewest siting constraints. It may be important to review the technical material with the experts who prepared it to determine the modifications or disturbances which would be least harmful. For geologic instability, for example, areas of small surficial instability are normally easier to correct or stabilize that deep-seated landslides. Certain types of vegetation may be easier to relocate than others.
3.C. All options must be provided to the reviewing planners Once the minimum options for development are prepared, they should be described in sufficient detail that the reviewing planners can clearly understand the tradeoffs that are involved. For example, one option may direct development into the location of a minor slide that would require some removal of material and the construction of a series of small retaining walls, while another option might require the removal of four mature oak trees, with a commitment to plant six new trees on another portion of the site. It is the responsibility ofthe coastal planners who know the region and have an overall awareness of the significance of various resources to determine which of these options would minimize overall resource impacts and best meet the goals of the Coastal Act or LCP.
4.A. Goals of an access plan The major goal of any access plan is to provide safe, all-weather access to property, with a level of service suitable to intensity of use. This may consist of one or more safe and easy routes in and out of a site which can be used by construction equipment, delivery trucks, residents and all necessary safety equipment. Some level of access must be available during and after disaster events such as fires, floods, earthquakes, landslides, etc., and the people who need to use this access must know both that it exists and how to get to it. For example, an unpaved, secondary access road will only be a useful emergency backup if it is identified and marked at key intersections with major roads. In addition to these major uses, road access can provide parking, routing for utilities, and, if planned properly, some level of drainage control.
4.B. Access should fit into the existing land form For subdivisions or lot development, the primary use of the property is associated with the buildings and access is a secondary, but necessary component. Access may dictate where buildings can be located, but access should not dominate or overwhelm the primary land development. Whenever the site alteration is driven by the access requirements, these requirements for access and the proposed level of service should be examined.
4.C. Access should complement efforts to protect or control drainage Access roads provide a collecting point for surface runoff and can redirect sheet flow into a concentrated source. If these drainage aspects of access are ignored, it is likely that they will cause unanticipated erosion and sedimentation. Access roads should be viewed as collectors and incorporated into the overall drainage design for the site. In additional, access should avoid stream crossings and where unavoidable, cross at a narrow portion of stream and at right angles to flow direction. During storm events, access roads can become, in effect, tributaries to the streams and if the access diverts significant amounts of flow into the stream, in a location where it had not occurred naturally, the stream flow characteristics can be altered, causing gullying, scour, sedimentation or other modifications. If stream crossings cannot be avoided, they must be designed carefully and in a way to minimum any change to natural drainage characteristics. Section VII shows different options for stream crossings which might be appropriate for unavoidable crossings.
4.D. Access for fire equipment or other safety vehicles One of the biggest issues for access is access for emergencies. In normal activities, a narrow, windy road may be a slight impediment to quick travel , but in the case in an emergency, it may be a critical problem. If fire safety were to dictate all components of a subdivision design, all roads would have numerous wide lanes, large radii on curves, and no dips or rises, there would be no vegetation anywhere near either roads or structures, and every site would have hydrants or large water storage areas (tanks, ponds, etc.). In rugged, steep hilly or mountainous terrain it is often difficult to provide ideal fire access. Some possible access ideas are shown in Section VII, providing a wide-two lane road, splitting the access into two one-lane roads, or using a one-lane road with turn-arounds. Access options must be discussed with the fire district or districts which provide fire service to the area.
4.E. Many road standards may be negotiable Fire safety standards have been developed for many elements of a site, including access, utilities, plantings, roofs and chimneys. The Department of Forestry and Fire Protection recently prepared "Fire Safety Guides for Residential Development in California". This Guide discusses many of the Recommended Fire Safety Standards, their rationale and some of the land use and county general plans which can address fire safety. Every access plan must provide for the key elements of emergency access -- letting the emergency equipment get into the site while letting endangered residence get out; however, in some cases, it may be possible to modify the access standards to match the constraints of an area. Some communities, such as in Marin County have mounted fire equipment of four wheel drive vehicles so fire vehicles can use the narrow surface streets which occur through much of the county. For a large subdivision, it may be more reasonable for the subdivision to provide fire vehicles that can use limited access, rather than building an enormous access road. Some areas may be able to reduce the size of equipment that must get to the site by providing on-site supplies of water, in ponds, swimming pools or water tanks. In other areas, it may be appropriate to provide a locked, unpaved secondary fire road which fire equipment can use for access, allowing residents to evacuate on regular surface roads. When access is an issue, the planner should negotiate with the fire district to see if there can be alternative ways to meet the main goals for emergency access. The need for emergency protection is not negotiable; the ways to provide it may be.
5.A. Goals for site stability Geologic surveys of a parcel should be used to identify and avoid all hazardous and unstable areas on the site. When an unstable area cannot be completely avoided, the goal of stabilization efforts is to provide for safe site development and long-term use. Temporary stabilization should only be considered which there will be no long-term use of the area that could be threatened by possible failure in the future.
5.B. Maintenance of stabilization must be considered Long-term stabilization should be as maintenance-free as possible, but when maintenance is required, the developer and all future property owners should be aware of the maintenance. In many situations it would be appropriate to have written programs specifying schedules and responsibilities for inspection and maintenance.
5.C. Keep drainage away from landslide prone areas and engineered slopes Surface water as well as groundwater can trigger slope instability. Drainage must be carefully controlled to avoid triggering a slide or destabilizing an engineered slope. Since access often functions as a drainage conduit, it should not be located near or through a slide area. If such access cannot be avoided, drainage controls are critical.
5.D. Engineers can often design slope stabilization to fit planning criteria When slope stabilization is required, it must be designed and constructed to provide an acceptable level of safety. Engineers often have a variety of options which can be used to provide stability; Section VI illustrate some of the more standard ways to stabilize a site. Planners cannot specify details of the stabilization plan, but they can and should provide guidance on what resource areas must be avoided for a stabilization option or what visual characteristics would or would not be acceptable. For example, if the slope must be able to support natural vegetation following stabilization, the engineer would not consider a high retaining wall as an alternative. The planning guidance regarding eventual vegetation requirements provides some clear direction as to what would be an acceptable planning solution and is better guidance than stating that a retaining wall cannot be used.
6.A. Goals for a building foundation A building foundation is the base upon which a building will be placed. At a minimum, a foundation should be thought of as a safe, stable platform for the rest of the building. The foundation design will often provide protection for the rest of the building, as well as the occupants, from floods, soil settlement, surface failures, etc. The foundation must also insure that the building will conform to the characteristics of the site.
6.B. Building foundations must consider the hazards and resources of a site Just as a site cannot accommodate every type of development, most sites cannot accommodate every type of building foundation. In a flood plain where buildings must be elevated above the flood elevation, pier or caisson foundations may be very useful. On a marine terrace, a slab-on grade foundation may be preferable and where bedrock may be fifty or sixty feet below the surface, a pier foundation may be completely impracticable. On steep terrain, pier foundations or a multi-level foundation may be more useful. Section VIII shows different foundation styles and discusses the benefits of each.
6.C. The size of the buildable area should equal or exceed the size of the building pad If there are any "buildable areas" on the site (buildable areas are those areas where there would be no adverse effects whatsoever from access to them or from development on them), the developer should examine development designs which would occupy these areas. If a small buildable area exists on a site, the building should be designed to fit suitably within these limits. Both the area of the building and its height should be scaled to the site; a towering but narrow building may fit on a building pad, but it could be inappropriate for many locations. If there are several buildable areas in a cluster, the site design may require that several small buildings be used, rather than one large structure. For example, when it was discovered that a trace of the Malibu Coast Fault ran through the site proposed for development as a hotel, the hotel structure was designed as a group of small buildings that could be setback from the trace, leaving the fault trace as an open corridor through the hotel complex. Similarly a residence could be made up of several small buildings connected by pathways.
6.D. Developable lots cannot always accommodate extensive development Many lots can be used for a variety of uses or can fit a variety of building designs and styles. In areas where lots have numerous development constraints, the options for building size and design may be severely limited by the physical conditions of the site. Generally, the larger the building size the more difficult it is will be to site, and the greater the physical constraints of a piece of property, the fewer the options for building styles. Many constrained sites may provide spectacular views, wooded serenity, or isolation, but the developer may have to balance these qualities with small scale developments and low intensity uses. If developed, sites with development constraints may not be able to accommodate any accessory structures or uses, such as guest houses or stables.
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