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1 <br /> ( January la, 1998 <br /> (, . <br /> Projec� No. G95103A <br /> � III. HIITIGATION RECONII�IENDATIONS <br /> ITable 3 presents a matrix of miagating measures and unavoidable impacu for the projcct siu. As <br /> I can be seea from Table 3, the proposed projxt, as we presently understand it, could be developed <br /> without significant adverse impacts from a geologic standpoint, provided that the mitigatioas <br /> outlined below are properly followed. <br /> l <br /> 10.0 LANDSLIDE HAZARD MITIGATION <br /> I <br /> I To midgate the risk of damage and environmental impacu from landslides, we recummend a <br /> building setback timit of 50 feet from the top of slope above Narbeck Crak. The building setback <br /> I limit from the top of slope adjacent to the East Fork of Powder Mill Crcek may be reduced to 25 <br /> � feec. <br /> 1 11.0 FROgION IiAZ.�R� MTTIC*ATION <br /> � Prior to development at the site, a comprohensive erosion hazacd and sediment transport control <br /> plan should be completed. Storm water nmoff from development should not be d'uxted onto the <br /> � existing on-site drainages without midgating msasures, or further study that determi�s that these <br /> drainages can handle tlie i�mased flow without adverse impacts. The recommendations presented <br /> in this report are based on the existing morphologies of the drainages at the siu and on the <br /> f assumpdon the gully erosion will not be accelerated by development in the surrounding area. <br /> ! Presented below aze preliminary mitigation measures designed to reduce the erosion 6azard <br /> potential and off-siu sediment u�ansport from both sheet and gully erosion regimes resulting from <br /> Idevelopment of the subject property. <br /> 1) Steep slopes designated Zones 2 or 3 should not be cleared of vegetadon since t�is <br /> j would promote erosion and reduce the stahility of the slopes. Clearing within Zone 1 <br /> } should be lunited to immediate areas of consauction anl :�reas suipped of vegetation <br /> Iduring construcdon should be replanud as soon as possible, or o[herwise protected. <br /> 2) Silt fences should be placed along tLe lower elevadons of disturbed areas and chxk <br /> Idams should be used along roadways. <br /> ,3; Surface water discharge should be controlled during and following consauction. <br /> � Surface runoff and domestic discharge should not be dimted onw sloping areas, but <br /> should be direcud into a tightli�d system tLat discharges to a suitablc sWrm water <br /> conuol system with velceiry and sediment trap contcol structures. Ouffall erosion <br /> ' <br /> 12 <br /> � <br />