Table of Contents
Subdivision regulations typically cover lot and block design, street design and improvements, drainage easements, layout of utility systems, and water distribution systems. Site design standards address a wide variety of site-specific design and operational issues such as parking (lot layout, location, and design), landscaping, exterior lighting, and trash enclosures. Key elements related to subdivision and site design that specifically address natural hazards include:
- Suitability of land for subdivision;
- Subdivision improvement agreements;
- Standards for natural hazard area mitigation, including but not limited to flood hazard, geologic hazard, and wildfire hazard; and
- Cross-references to zoning, site development, and subdivision requirements.
The following sections provide example language for each of the common elements. Model language is in gray shading. Commentary is located in italics in the column at the right. The model language used in this document is based on several existing ordinances and programs from varying communities around the state, including municipalities and counties. The language is illustrative only; consult local counsel to tailor language for your jurisdiction.
Subdivision regulations often specifically prohibit the subdivision and subsequent development of land found to have or be subject to natural hazards. This prohibition often is included in the general design standards of the jurisdiction’s subdivision regulations.
Suitability of Land for Subdivision: Land subject to natural hazards such as flooding, wildfire, falling rock, landslides, and avalanches shall be considered unsuitable for any occupancy that may impair the health, safety, or welfare of the inhabitants. Such land shall be identified and shall not be subdivided until the hazards have been mitigated or will be mitigated by the subdivision and construction plans in accordance with the Sensitive Area Protection Standards of this Land Development Code. Where such hazardous conditions are adjacent to lands proposed for subdivision, the proposal may be denied unless potentially hazardous conditions are appropriately mitigated per this Code.
Suitability of Land for Subdivision: Some subdivision codes contain standards for natural hazards mitigation or sensitive area mitigation. The Teller County subdivision regulations have a “Site and Development Goals, Objectives, and Guidelines” table stating design requirements for geologic, fire, flood and slope hazards.
Land that is subject to hazardous conditions may need specific mitigation improvements that will be completed pursuant to a Development or Subdivision Improvement Agreement. The terms of this agreement should specify the work that will be completed and time-frame for completion. The long-term maintenance of such improvements will need to be identified in that agreement, as well. This agreement will need to be accepted by both the developer and the governing board of the local jurisdiction. As well, the developer will need to post a bond or letter of credit sufficient to complete the improvements as specified in the agreement.
If land with hazardous conditions is to remain undeveloped within the subdivision, an easement or deed restriction should be recorded specifically restricting its development and use based on the conditions posed by the natural hazard. The subdivision plat should specifically show the area to be restricted from development and reference the recorded easement or deed restriction.
A. Purpose: Certain areas of [name of local government] contain natural resources that contribute to the [name of local government] character, such as waterways, wetlands and drainages, wildlife habitat, viewsheds, and hillsides. There are also certain areas that may pose hazards to property, infrastructure, and public safety because of natural hazard conditions on or adjacent to buildable lots, including flooding, geologic conditions, wildfire hazard, or soil conditions. The standards of this section are intended to ensure that environmental features are protected, the natural character of [name of local government] is maintained, and development on potentially hazardous lands protects inhabitants and minimizes environmental and aesthetic impacts.
B. General Site Design: Developments shall minimize impacts to sensitive natural resources, natural hazards, and other unique and fragile site elements including but not limited to wetlands, open space, and steep slopes. Such resources and features shall be preserved where practicable. Subdivisions and any development shall be designed to preserve existing waterways (lakes, rivers, and streams), primary vegetation (trees), rock formations, and other natural vistas, as well as other environmental resources and features.
C. Slopes: Steep land (30 percent or greater slopes), unstable ground, and land subject to hazards such as landslides, rockfall, ground subsidence, wildfire, or flooding shall not be platted or developed for residential or other uses that may endanger life and limb or habitable improvements, unless appropriate provisions, as deemed necessary by the [Building Department], are made to eliminate or control the hazard.
D. Natural Features: Subdivisions and any development shall make every effort to preserve existing waterways (lakes, rivers, and streams), primary vegetation (trees), rock formations, and other natural vistas.
E. Flood Hazard Areas: The [Planning Department] shall keep on file and available to the public a set of maps showing all known and identified areas of special flood hazard in [name of local government]. A subdivision or development in a special flood hazard area shall not be approved unless adequate evidence, prepared by a registered professional engineer, is submitted that shows the proposed subdivision or development is not in an area of special flood hazard or that the conditions of Section [X.X], Floodplain Regulations, will be met.
F. Geologic Hazard Areas: The [Planning Department] shall keep on file and available to the public a set of maps clearly showing all known and identified geologic hazard areas in the [name of local government], as such become available. [name of local government] shall not approve any subdivision plan or site plan if the proposed subdivision or development is either in one of these identified geologic hazard areas or is in an area suspected of being in a geologic hazard area, unless the applicant can submit adequate evidence, prepared by a registered professional geotechnical engineer, that the proposed subdivision or development meets the following conditions:
- Provisions have been made for the long-term health, welfare, and safety of the public from geologic hazards to life, property, and improvements;
- The proposed development will not create an undue financial burden on the existing or future residents of the area or community as a result of damage due to geologic hazards;
- Structures designed for human occupancy or use will be constructed to prevent danger to human life or property;
- Permitted land uses, including public facilities serving such use, will avoid or mitigate geologic hazards at the time of initial construction; and
- Man-made changes will not initiate or intensify adverse natural conditions within a geologic hazard area.
G. Wildfire Hazard Areas: The [Planning Department] shall keep on file and available to the public a set of maps clearly showing all known and identified wildfire hazard areas in the [name of local government], as such become available. The [name of local government] shall not approve any subdivision plan or site plan if the proposed subdivision or development is in an area identified as a wildfire hazard area or is in an area suspected of being in a wildfire hazard area, unless the applicant can submit adequate evidence, prepared by a qualified professional forester, that the proposed subdivision or development meets the following conditions:
- Any development in which residential activity is to take place shall be designed to minimize significant wildfire hazards to public health, safety, and property;
- Any development will have adequate roads for emergency service by fire trucks, firefighting personnel, and fire breaks or other means of alleviating conditions conducive to wildfire hazard;
- Precautions required to reduce or eliminate wildfire hazards will be provided at the time of initial development;
- All subdivision and development will adhere to the Guidelines and Criteria for Wildfire Hazard Areas published by the Colorado State Forest Service; and
- Consideration of recommendations of the State Forest Service resulting from review of a proposed subdivision or development in a wildfire hazard area.
Suitability of Land for Subdivision: Some subdivision codes contain standards for natural hazards mitigation or sensitive area mitigation. The Teller County subdivision regulations have a “Site and Development Goals, Objectives, and Guidelines” table stating design requirements for geologic, fire, flood and slope hazards.
Sensitive Area Protection Standards: These are site layout/design standards similar to other required site design standards applicable to all development, whether in a new subdivision or a redevelopment/re-use of property on previously subdivided land. They are typically included in the jurisdiction’s code and generally applicable to development and design standards since they are intended to apply to projects where subdivision may not be required, as well as new subdivisions.
Steep Slopes and Natural Features: Areas of particular sensitivity should be listed based on local environmental hazard assessments. In the model code example, two types of sensitive features are included: one to illustrate a natural hazard condition (steep slopes) and the other to describe an example of important local characteristics (natural Features). Local communities could identify other important visual and ecological features for protection under this section, as well as natural hazards.
Preliminary Plat Review by Technical Experts: Counties are required by state statutes (C.R.S. §30-28-136) to submit preliminary plats to the Colorado Geological Survey for an evaluation of those geologic factors that would have a significant impact on the proposed use of land, and to the Colorado State Forest Service and local conservation district to review of wildfire, soil suitability, and any potential flooding issues.
Hazard Areas: Teller County uses a table format in its subdivision regulations that details design guidelines for specific objectives related to geologic, fire, flood and slope hazards. These guidelines must be met for a subdivision to be approved. The guidelines include use of building techniques, such as use of fire retarding roof and exterior wall materials to mitigate wildfire hazard, as part of a subdivision requirement.