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Chapter 3. Hydropower Rhode Island Renewable Energy Siting Partnership
use and value for navigation, and thus assure protection of the public health, safety, welfare, a healthy economy and the environment.”
RIDEM evaluates applications for water diversion permits by using a Streamflow Depletion Methodology SDM. The SDM is a tool that calculates “the volume of water that can
be extracted from a stream whether as direct stream withdrawals or indirect groundwater withdrawals while still leaving sufficient flow to maintain habitat conditions essential to a
healthy aquatic ecosystem RIDEM 2010b.” Under this methodology, RIDEM calculates allowable water depletions from streams and groundwater according to the natural and human
needs and influences within each watershed. New uses of stream water and groundwater are required to consult with RIDEM about obtaining a permit if they represent withdrawals of more
than 10,000 gallons of water per day. RIDEM issues a permit only if the project is determined to leave “enough remaining capacity in the net available streamflow depletion to accommodate the
proposed withdrawal.” Permit requirements for hydropower projects will vary on a case by case basis and depend on both the size of the streamflow diversion resulting from a project and the
streamflow requirements of the watershed.
4.2.2 Wetlands Permit
The R.I. Freshwater Wetlands Act R.I. Gen. Laws 2-1-18 et seq. and its associated Freshwater Wetlands Rules and Regulations were instituted to “to preserve the purity and
integrity of the swamps, marshes, and other fresh water wetlands of this state R.I. Gen. Laws 2- 1-19.
” The Freshwater Wetlands Act requires landowners to obtain a permit from RIDEM in order to “excavate; drain; fill; place trash, garbage, sewage, highway runoff, drainage ditch
effluents, earth, rock, borrow, gravel, sand, clay, peat, or other materials or effluents upon; divert water flows into or out of; dike; dam; divert; change; add to or take from or otherwise alter the
character of any fresh water wetland R.I. Gen. Laws 2-1- 21.” Hydropower projects located
near wetlands may require freshwater wetlands permits, particularly where a wetland is present as a result of the impoundment created by the dam that will support hydropower.
4.2.3 Discharge of Dredge Material
RIDEM is authorized by the federal CWA and state Water Pollution Control Act to regulate discharge of pollutants, including dredge spoils, in waterways within the state of Rhode
Island. The statute defines a pollutant as “any material or effluent which may alter the chemical, physical, biological, or radiological characteristics andor integrity of water, including but not
limited to dredged spoil R.I. Gen. Laws 46-12- 1.” To this end, RIDEM issues permits for
disposal of dredge spoil and establishes water quality standards that conform to the EPA’s applicable water quality rules and regulations with regards to the dredging and disposal of
sediments. Hydropower projects that involve the dredging andor filling of a body of water in order to install power generation equipment may require a water quality permit from RIDEM.
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Chapter 3. Hydropower Rhode Island Renewable Energy Siting Partnership
4.2.4 Obstructions to Navigation
