5300 GLENWOOD AVE 2018-01-02 MF Import

. , ._ _ , . . . ._ r Glcmvood Terrace Filc Number 12G994 May 12, 1994 Pagc 20 Once the drains are insGillcd, Uie cxcavalion within an l8 inch Iwrizonfal distancc behind the footing or ��alls should bc b�ckfilled with a grnnulnr stractural fill, exapt the top 12 inchcs which should be a laper of compacicd, native, impemieable soil. 7his impertneable cap material should be separated from the granular soil by a laycr of building paper or visquine sheeting. The ground surface should bc sloped to dnin a��ay from d�e buildings. Undcr no circumslances should roof downspout drain pipes be connected to the footing dmin systcm. All roof do�mspout drains must be separatcly tightlined to discharge. 71�e Tooting drain system should have a minimum of 12 inches of vertical fall beforc it is connected to the storm wutcr systcm. \Vc rccommend that su�cicnt cle.inouts be installed at strategic locations to allow for periodic maintenance of the Cooting drain and doµnspout dninpiae system. Storm �Vater�Vet Pond and Vuult General: 'Ilie proposed location oFthe stonn tvamr wet pond is sho��m on Figure 2. The pond is expected to utilizc partial excavation inlo the subsur(ace soils, and constructcd bemis around the outside to hold waler in place. From the pond, the��atcr will then be dirccted through thc bemi to :ui oulfall systcm ncar Uic crcck. Site Preparalion and Crading: Silc prcparation and grading should be perfortned as discussed in the Slruclurnl Fill subscction of tl�is report. Whcre Qie bcnn for the pond is to bc construcled,the existing fill sliould bc removcd down to die mcdium densc or bettcr sands. 'll�e pond should be overexcavated to allow far thc lincr discusscd in tlic Wet PonJ nnd Benn Design sub-section below. The interior of Uie pond,and dic txmi areas, nre expected to require cut. Are,1s to receive ne�v fill should be stripped of unsuitable surface soils and existing fill, :uid compacted lo a non-yiclding state prior lo placemcnt of U�e new fill. Tl�c cxa�vation should be kcpt dry to allow placcmcnt of fill. If �vatcr is cncoumercd in dic excavations, lemporary drains or sumps should be used to remove tlie watcr from areas to receive structural fill. 5hallow�sclls may be necded in this�ma to kccp Ihc excavation dry enough to complctc thc enNi�eork. \Vet Pond and flenn DesiQn: We recommcnd that tl�e ponJ bc lincd to provent cxcess secpage into thc slopc. 'Ilie liner couid consist of a low permcability soil or a symtl�etic type. We rcconvnend that the lincr matcrinl have a pcnncability rate of Icss tl�an 1x10�s ccntiroctcrs per sccond (cndscc). 71ie un-sitc Qvt, founJ in t]�e upper portion of Ow ridgc planncd to bc excavated, may be suitablc for usc as a liner. We reconuncnd that thc proposcd lincr mntcrial bc providcd to us�t the time oCconstruction for cvalu�tion and NELSON-COUVRETTE 6 ASSOC/ATES, INC. FFB-23-t996 12:]3 2�Jb 491 2510 96i P.22