7.7 Supplementary drainage requirements


Increase in impervious cover of 10% or more triggers requirement to manage stormwater and control erosion.Prohibits increase in off-site runoff volume and erosion from land alteration on individual lots. Stormwater must be managed to prevent flooding or impaired use of adjoining properties.
7.7 Supplementary drainage requirementsNo land alteration, construction, or development in the town of Narragansett may result in an increase in the rate or volume of stormwater runoff, erosion, or sedimentation off-site or downstream. All proposed construction and development which will increase the impervious surface on any lot or tract by more than ten percent of the lot area shall include systems to manage stormwater and to control erosion and sediment.(1) Stormwater management. The stormwater management system for any site shall be designed to offset the increase in the rate of stormwater resulting from the proposed development. It shall implement the techniques and measures recommended in the most current revision of or supplement to \”Urban Hydrology for Small Watersheds, Technical Release No. 55,\” prepared by the United States Department of Agriculture, Soil Conservation Service.

The system shall incorporate, to the maximum extent practicable, the natural drainage features of the site, including natural drainageways and permanent and periodic ponding areas. It also shall include stormwater control facilities such as pipes, ditches, culverts, swales, and, if necessary, water retention areas and structures.

The system shall prevent the discharge of stormwater runoff onto adjoining property in a manner which causes flooding or impairs the use or development of the property. Temporary stormwater and erosion control facilities adequate to protect adjoining property shall be installed at the commencement of construction, excavation, grading, or removal of vegetation. For purposes of this section, any property which faces a construction site across any street or highway shall be deemed adjoining property.

Appendix A Zoning,
Section 7. Supplementary Zoning Regulations
7.7 Supplementary drainage requirements
Last Accessed: 2009-11-19