08/22/2011 - re: wetland buffer compl

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. f August 22, 2011 4701 West Branch Road Page 3 of 4 (c) Buffer area widths will be based on the wetland protection strategies established in the Orono Surface Water Management Plan (SWMP) (December 2002). A protection classification has been assigned to each wetland in Orono based on the stormwater susceptibility and functional assessment for each wetland. The four protection classifications are described as follows: Protection Susceptibility Rating Description Classification "Preserve" Highly Susceptible Highly susceptible to both quantity and quality impacts from runoff; have the highest degree of protection "Manage 1" Moderately Moderately susceptible to quantity and quality Susceptible impacts; protection is less stringent than Preserve, provides protection to maintain their characteristics "Manage 2" Slightly Susceptible Less stringent protection than Manage 1 wetlands; maintenance of characteristics is desirable . "Manage 3" Least Susceptible Wetlands are significantly degraded (e.g., cultivated or canary grass monotype) or lack of wetland characteristics; not typically impacted by runoff; no quantity and only limited quality treatment of runoff is required The protection classification for each wetland will be found on the "Wetland Management Classification Map & List" which is hereby adopted by reference, a copy of which shall be kept on file in the office of the city clerk and shall be available for public review during all normal office hours. The following are the required buffer area widths for each protection classification: Protection Classification Width of Buffer Area Additional Protection Requirements from Wetland (B = Bounce = Change in water level Boundary due to runoff event) (P = Phosphorus) "Preserve" 50 feet B: Maintain bounce at or below existing conditions P: Limit loadings to predevelopment loading (0.14 Lbs./Ac/Yr) "Manage 1" 35 feet B: Maintain bounce at or below existing conditions plus 0.5 foot P: Limit loadings to predevelopment loadings times 2 (0.28 Lbs/Ac/Yr) "Manage 2" 25 feet B: Maintain bounce at or below existing conditions plus 1.0 foot P: Limit concentration to predevelopment concentrations (200 ppb) "Manage 3" 16.5 feet B: No quantity requirement P: Limit concentration to 225 ppb (d) In cases of new development or redevelopment the city shall require that vegetation in the wetland buffer be installed prior to the issuance of the certificate of occupancy. The city may waive this requirement in lieu of a cash escrow or letter of credit equal to 150 percent of the cost to install the required buffer. (e) The city may allow the disturbance of an existing buffer area during the course of construction activity. This disturbance must be kept to a minimum, soils must be decompacted to a level that will accommodate root growth, and the buffer area must be re-established as required by the city. The city will determine the amount of allowable disturbance. The city may require a cash escrow or letter of credit equal to 150 percent of the cost to re-establish the buffer to its original condition.