10105 19TH AVE SE 2018-01-02 MF Import

.. � : - .__ I � , ' ; � Slarmwaler Sire Plan jor Norlhwest,1 nlmal Care May 19,2002 1 SECTION III OFF-SITE ANALYSIS � Drainage Syatem Description I The existing site has no constructed drainage system. Existing site runoff flows overland to the i southwest to coll�xt on the.east cutb of 19'h Avenue SE. Areas upslope of the site are to the north and west. The parcel to the north is undeveloped and some surface runoff may flow into the site as is � suggested by the topography. 'fhe quantity of runoff is likely to be small as[he property is well ; vegetated. Some minor amounts of ruv.off may flow into the site from the rear yazds of the ; Iresidential parcels to the east. The runoff is likely insignificant. Runoff exiting the site enters the 19'�Avenue right-of-way and flows south in the gutter on the I� �_ east side of the road. The drainage flows into a curb-side catch basin about 50 fcet south of the southwest site comer. The flow continues south inside a 24-inch diameter public storm sewer. � The storr,l sewer size increases to 30-inch and eventually discharges into the north end of Silver Lake. Exiating Drainage Probleros � No existing drainage problems wcre observed during the inspection. Flooding or erosioi� problems were not evidznt. Potential problems may include water quality concems for Silver I � Lake that are typical of urban water bodies. ! Project MiYigations 1 _ Detention and water q�ality facilities will be provided to mitigate potential storm water impacts from the development. The detention system is designed to stringent City detention standards I I and therefore the development is not expected to impact the existing system capacity. Watet quality facilities include settlement storage and biological treaUnent. The water quality impact of the development is expected to be negligible. I IP�� I �(