MODULE-4 Land Use Planning

Conventional Regulatory Techniques

Subdivision Rules and Regulations

Subdivision rules and regulations supplement zoning ordinances in that they focus less on land use and more on road layout, site design, and engineering concerns such as road construction and utilities. A subdivision regulation controls how a parcel of land is divided for development purposes. It does so by providing standards for the design and layout of lots, streets, utilities, and other public improvements. Protecting water resources via subdivision regulations can be used to ensure that drainage and landscaping designs fit with the goal of resource protection. Following are some important subdivision controls to consider.

  • Drainage Requirements
  • Environmental Impact Assessments
  • Performance Standards
  • Site Design/Landscaping

Drainage Requirements

Stormwater runoff from subdivisions often contributes nutrients, metals, and other contaminates to water supplies. To help control this problem, drainage requirements may be established by local planning commissions and boards as part of subdivision review processes. (Drainage best management practices are also effective in non-subdivision areas.)

Effective drainage management should minimize the volume of runoff generated as well as enhance treatment and the attenuation of pollutants. Steepness of constructed slopes should be minimized, and bare surfaces revegetated as quickly as possible. Module 6 discusses Low Impact Development/Alternative Design techniques for drainage.

Environmental Impact Assessments

Proposed subdivisions exceeding a minimum size, such as 10 lots, may be required to prepare Environmental Impact Assessments (EIAs). EIAs may include varying information, depending on community needs and water resource protection goals. Possible requirements are: identification of sensitive water receptors on site and downgradient, information as to existing condition of these resources, and potential impacts from the proposed development on sensitive resources.

Performance Standards

Subdivisions may be regulated on the degree of impact the full development could have on water resources. Performance standards, such as nitrogen and phosphorus loading limitations, may then be specified to keep contamination from the subdivision below assimilation of the downgradient water resource. The developer can be required to determine impacts, perhaps through the EIA process (above).

Site Design/Landscaping

Water quality protection may be enhanced via requirements for vegetated buffer zones, natural landscaping in key areas and the reduction of impervious areas through stringent percent cover standards and alternative roadway designs. In establishing landscaping requirements, communities should encourage xeriscaping techniques. Xeriscaping focuses on the use of native plant materials having lower water and nutrient requirements than standard landscape species. Use of highly demanding exotics should be discouraged.

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