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CITY OF EVERETT STORMWATER MANACsEMENT MANUAL <br /> • The windthrow hazard of Pacific Silver Fir and Madcona is high,while that of Westem hemlock I <br /> is moderate. The danger of windthrow incteases wherc dense stands have been t}timed. Other <br /> specics(unless they are on s6alfow,wet soils less ttian 20 inches deep)haee a low windthrow <br /> hazazcf. <br /> • Cottonwoods,maples,and willows have water-seeking roots. T6ese can cause trouble in sewer <br /> lines and infiltratiun fields. On the other hsnd,they thrive in high moisture condiaons that other <br /> trees would not. <br /> • 'Chinning operations in pure or mined stands of Grand F'v,Pacific Silver Fir,Noble Fir, Sitka <br /> Spcuce,Westem Red Cedaz,Westecn Hemlock,Pacific Dogwood, and Red Alder can causc <br /> serious disease problems. Disease can become esta6lishcd through damaged limbs,wnks,roots, <br /> and freshly cut stumps. Dise�ced and weakened trces are also susceptible to insect anack <br /> Maintenance Standards <br /> L lnspect flagged and/or fenced areaz regulazly to make sure flagging or fenci��g hes not been <br /> rcmoved or damaged. If ihe flagging or feocing has been damaged or visibility reduced,it shali <br /> be repaired or replaced immediately and visibility restored. <br /> 2. If tree roou have been exposed ot injured,pcune cleanly with an appropriate ptuning saw or <br /> Iepers dirccUy above the demaged roots and recover with native soils. Treatment of sap Oowing <br /> trees(5r,6emlock,pine,soft maples)is not adviscd as sap fortns a natural healing bartier. <br /> 3.2.2 BMP C102: BufFer zones <br /> Purpose <br /> M undisturbed area or strip of natural vegetatian or an established suitable planting that will provide a � <br /> living filter to reduce soil erosion and runoff veloci6es. <br /> Cond/tions of Use <br /> Nalural buffer zones are used along streams,wetlends and other bodies of water that need protection from <br /> erosion and sedimentation. VegetaHvc buffer mnes can be used ro protect natural swales and can bc <br /> incmponted into the natural landscaping of an area. <br /> Critical-azeas buffer zones shall not be used as sedimcnt teatmcnt azeas. These areas shall rcmain <br /> completely undisturbed except as allowed by the Planning Department. . <br /> Deslgn and/nstallation Speclfications <br /> 1. Preserving natural vegetation or plantings in clumps,blocks,or strips is generally the casiest and <br /> most successFul method. <br /> 2. Leave all unstable steep slopes in natural vegetation. <br /> 3. Mark clearing limits and kecp all cquipment and conswction debris out oP the natural areas. <br /> High visibility plasric fencing is the most effective method in proteciing scnsitivc azeas and <br /> buffers. Altematively,wire-backed silt fence on steel posts is marginally effectivc. Flagging <br /> alone is typically not effective. <br /> 4. Keep all excavations outside the dripline of trccs and shrubs. <br /> 5. Do not push debris or extta soil into the buf[er zonc arca bccause it will cause damagc from <br /> bur,ying and smothering. <br /> 6. Vegetative buffer zooes for streams,lakes or othet watenvays shall be established by the Ciry or <br /> other state or federal pertnits or approvals. <br /> Volume II—Construc6on StormwaterPollution Prevention <br /> 3-3 <br />