Section 096-502-3 - CriteriaThe criteria in this section are used to identify the direct watersheds of lakes most at risk from new development and urban impaired streams.
The criteria apply for both projects requiring a stormwater permit and developments requiring a Site Law permit, unless otherwise specifically stated.
A.Direct watershed of a lake most at risk from new development. Lakes most at risk from new development are listed in Appendix A of this chapter. A lake is considered most at risk from new development if it meets the criteria below: (1) A public water supply; or(2) Identified by the department as being in violation of class GPA water quality standards or as particularly sensitive to eutrophication based on: (a) Current water quality,(b) Potential for internal recycling of phosphorus, (c) Potential as a cold water fishery, (d) Volume and flushing rate, or (e) Projected growth rate in the watershed. Severely blooming lakes are a subset of lakes most at risk. A severely blooming lake has a history of algal blooms, and the reduction of existing watershed phosphorus sources sufficient to eliminate those algal blooms is expected to be so difficult that the addition of new, incompletely mitigated development sources may prevent successful restoration of the lake.
B.Urban impaired streams. A stream is considered impaired if it fails to meet water quality standards because of effects of stormwater runoff from developed land. Additional stormwater treatment controls are necessary in urban watersheds of impaired streams because proposed stormwater sources in urban and urbanizing areas contribute to the further degradation of stream water quality. Urban impaired streams are listed in Appendix B of this rule and include all streams where violations of water quality classification standards have been documented for which urban stormwater has been identified as a significant cause. Urban impaired streams are considered "degraded, sensitive or threatened regions or watersheds" as described in 38 M.R.S.§420-D(4).06- 096 C.M.R. ch. 502, § 3