ISDS 



or areas of potential water supply where combined flow exceeds 2000 gpd; c) large 

 systems and subdivisions in all other areas where potential waste flow exceeds 5000 gpd. 

 (Dr. D. Urish, associated with the U.R.I. Civil Engineering Department, is currently 

 developing cumulative impact assessment procedures under contract to DEM.) A formula- 

 based system has been applied successfully in Falmouth, Massachusetts. Connecticut and 

 New Hampshire both use loadings formulas to determine lot size requirements. 



Use existing basin plans to identify areas where cumulative impacts represent a current or 

 future concern. 



Coastal Areas 



( Note: The Task Force designated only the Coastal Ponds as Critical Areas) 



*** Increase setback from 50 feet to establish 150 foot setback from all 

 parts of ISDS to poorly flushed coastal waterbodies, or their tributaries, 

 requiring applicants to acquire leach area easements as necessary. 



***Establish 100 foot setback from all parts of ISDS to coastal features, 

 and other coastal waterbodies, or their tributaries. 



***Due to frequent presence of excessively permeable outwash soils 

 (percolation rate exceeding 5 minlinch), establish four foot groundwater 

 separation requirement. Require five foot depth to the natural water table from original 

 ground surface. 



***Revise ISDS regulations and variance granting procedures to stipulate 

 that variances for standard system construction will not be granted in areas 

 where the water table is less than 3 feet below ground surface. 



**For large systems or subdivisions (combined flow exceeding 2000 gpd), 

 develop regulatory standards which provide for adequate separation based 

 upon soil conditions, effluent characteristics, and other site specific 

 conditions. Use of a point-based system such as tiiat described in SITE EVALUATION, 

 below, may be applied to determine the level of technical evaluation necessary to establish 

 design and siting requirements. 



**Develop cumulative impact assessment procedures based upon contaminant loading to 

 consider potential impacts of a) new systems in areas developed beyond carrying capacity, 

 and b) large systems and subdivisions where combined flow exceeds 2000 gpd. 



Groundwater Recharge Zones of Municipal Water Supplies 



Designate as Critical Areas all groundwater reservoirs currently or potentially suitable for 

 public water supply (as defined by the R.I. Water Resources Board) and their recharge 

 areas (as defined by USGS and/or DEM Division of Water Resources). 



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