1209 MADRONA AVE 2016-11-17 - Laserfiche WebLink

Geotechnical Engineerii�g Evaluation Packer Praperty Retaining Walls and Steep Slope E��aluation Evereri, Washington NGA File No. 870113 March 1 l, 2013 Page 10 Additional expenses could include the need for placin� additional erosion controi and temporary draina�e measures ta protect the slopes, the �ieed for placing a blai�lcet of rock spalls on exposed subgrades and consiruction traffic areas, and the need for importing all-weather material for strEtctural fill. Under nc� circumstances, should v��ater be allowed to flow over, or concentrate on the site slapes, both during canstniction and aft.er constructian has been completed, We recommend that stormwater runoff from the roof drains, yard drains, and other hard surfaces be collected and tightlined to a suitable discharge point at the bottom of the slope as is currently the case. These systems should be implemented and maintained on a reeular basis. The slopes should be protected from erosion. We recorr�mend that a11 disturbed areas be replanted with vegetation to re-establish vegetation cover as soon as poss:ble. �rosion ControI and Sloge Protectzon Nteasures The erosion hazard for the on-site soils zs listed as high, but the actual hazard will be dependent on h�� the site is graded and h�w u�ater is allowed to concentrate. Best Management Practices (BMPs) should be used to control erosion. Areas disturbed du�•ing constructian shouId be protected from erosian. Erosion contr�l rseasures may include divertinb surface water away from the stripped or disturbed az-eas. Silt fences and/or straw hales should be erected to prevent muddy water from leaving the site or flawing over the steep slope. Stockpiles should he covered with piastic sheeting during wet weather and stockpiled materiaI should be placed na closer than 3d feet from the top of the siope. Disturbed areas sliouid be planted as soon as practical, and the vegetation should be inaintained until it is establzshed. The erosion potential for areas not stripped �f vegetation should be low. Protection of the steep slope area should be performed as required by the City of Everett. Specifically, u�e recommend that after the recommended improvements are completed, the slope not be disturbed or modified through placement af any fill or removal of the vegetation. No additional material of any kind. should be placed on the slope or be allowed to reach the slope, such as excavation spoils, lawn clippings, and c�ther yard waste, trash, or sail stockpiles. Trees shauld not be cut down or remaved from the slope unless a mitigation plan is de��eloped, such as the replacement of vegetation for erosion protectian. Vegetatic�n should not be remaved from the slopes. Replacement af vegetation should be performed in accordance v��ith City of Everett code. Any future improvements ��ithin the backyard area should be the suhiect of a specific geotechnical evaluation. Under n� eircumstances should water be allowed to concentrate fln the steep slope. hiELSOiV GEOTEC�-!NlCAL ASSOCiATES, l�lC.