1230 MADRONA AVE 2016-01-01 MF Import

� April ]0,2005 Ptoposed Single-Pamily Residencc L&A Job iJo. SA019 Page 15 should be sloped and ditcl�es excavated along the bascs of ihc cut banks to direct rimoff and ground�vater into a swnp pit f�rm which watcr can be pumped into a storm sewer. 'fhc i�ilet of the storm sewer shoiild bc covered by a filter :ag to keep scdiments out of the sewer line. A layer of 2-inch cnished rock should Ue placed over undisturbed subgrade soils supporting foolings and on-grade slabs, as required, to protect the soils from disturbance by construction traffic. I2unofl'ovcr Impc�ti�ious Surfaces Storm runoff over impervious surf;ices, such as roofs and drivcway pavement, shotdd Ue collecled by anderground drain linc systems connecled to downsrouts and by calch basins installed in the pavcment. Slormwatcr thus collected should be tighUined to discharge into a slonn scwcr. Sufficicnt numbcrs of cleanouls �t strategic locations shoulcl bc pro��idcd to thc imdcrgruund drain liur svslcros to .dlu�� Ibr �,cria�lical cicinint uf thc druin lincs. I�uutin� I)r:�ins n subdruin should bc insl�illcd around thc perimctcr footings of thu proposed building and along lhe base of retnining �valls. "1'he suUdrains sl�ould consist of a 4-inch-mittimunrdiameter, perforated, rigicl, drain pipc, laid a few inchcs bclow bottom of the building perimeter footings or retaining �vall lootings. 7'hc trenches and the dr�in lincs should havc a sufficicnt gradicnt to gcucrale Ilow by gravity. The drain lincs should be emUedded in washed gr�vcl completcly ��rapped in non-woven (iller fiUric to �vithin about 12 inclics of finish grnde. The remaining trenches may be Uackfilled i��ith cican on-site soils, Sufficient ntnnbers of cfeanouts at straiegic locations should be providccl to the footing drain lines to allo�� for their periodical cleaning and maintenance. �1'ater collccted by the footing drains should Uc tighdined, separatcly from die roof and surf,icc slormwater drain systems, to discharge into a storm se��er. I�,tU � ASSOCIAT�S, INC.