2.3 STORMWATFR AND SEDIMENT 



Introduction 



The surge of development which has taken place in the Narragansett Bay Basin within 

 the past fifteen years has had numerous implications for the water quality of Narragansett 

 Bay. Urbanization has brought significant hydrological changes to bay watersheds. Not 

 only are erosion and sedimentation changing the configuration of drainage areas, but urban 

 runoff volumes and peak discharge levels are increasing at the same time that the quality of 

 runoff water is declining. 



Rhode Island's Areawide Water Quality Management Plan cited erosion and 

 sedimentation as the state's number one non-point source problem. More recently, urban 

 runoff has been identified as the source of very significant contaminant loadings to the Bay. 

 The Nationwide Urban Runoff Program research indicated that runoff firom lower density 

 residential and urbanizing areas may also contribute significant nutrient and chemical 

 loadings. 



Longstanding effons to alleviate flooding problems associated with decreased 

 infiltration area on a site have yielded well-established stmctural solutions to stormwater 

 management, but these solutions have neglected water quality considerations, and have 

 often contributed to water quality degradation. 



Similarly, erosion and sediment control have focused on flooding and drainage 

 considerations, neglecting factors determining water quality impact. In recognition of the 

 need to closely coordinate stormwater and erosion control programs and technical controls 

 for maximum effectiveness, this chapter addresses the two related issues joinUy. Special 

 problems relating to road deicing and impacts of lawn-care related contaminants are 

 approached in a separate section. 



THE STORMWATER AND EROSION CONTROL COMMITTEE 



In the fall of 1986, DEM formed a technical advisory group to develop guidelines for 

 stormwater management and erosion control. The initiative was undertaken in response to 

 several factors: a) specific issues of immediate concern in the Scituate Reservoir 

 watershed; b) a generally perceived need for technical guidance among resource managers, 

 regulators, and project designers; and c) the necessity of developing new program 

 direction as mandated by requirements of the new federal Clean Water Act amendments. 

 The committee was composed of professional engineers, academics, state regulatory staff, 

 municipal staff, and representatives of federal technical assistance programs, water supply 

 providers, and regional sewer authorities. 



The objectives of the committee were threefold: 



1. Develop standards and specifications for design and construction of stormwater 

 management facilities; 



2. Update the R. I. Erosion and Sediment Control Handbook for land development; 

 and 



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