5300 GLENWOOD AVE 2018-01-02 MF Import

, ( f Glrnwood Terracc � rile Number 126994 May IZ, 1994 Pagc 21 Icsting. Wc rccommend thnt thc soil lincr have a minimum horizonWl thiclmess of 2 fccl. A l foot wvcr shouid be placrd over 1he lincr to wpport vcgdation. Many times a syntlKtic lincr is more economical since it does not requirc compaction of moish�re srnsitive soils, it provides a positive seal end its installation ie r.ot as weather deprndent. We reconvnend t1�at the synthetic liner be placed in accordance ��ith the manufacturas recommcndatiau. Fill pl�ad nnd compacted within the pond and bertn sFwuld follow recommrndations as outlined in ihe Slructunl Fill sub-section of this aport. We rccommmd ihe fill in the pond and bertn be compaMed to a minimum o(92 percent of its maximum dry density aa dctcrminad by the ASTM D 1557 compection test procedurc. Whcrc fill is placed as liner material,each lift of the fill surfa�ro should be scarified to a dcpth of 2 inches,following mccting compaction crileria nnd prior to placanent oE thc next lilt. Thc purpose oC lhe scarification is to redua the risk of creating proRrcnlial sapage paths lhrough Ihe pond or berm. Deprnding on the final embanlanent dcsign,it may bc prudent to install a too drain along the outer one•tfiird of the bertn fill. TLc intrnt oCthe drain is eo redua seepage pres�ures thet wuld cau;c instability on thc downslope face of thc berm. 'Ihe ta drain should consist of a minimum tliickness of 12 incha of 2 inch cn�shai �ock (railroad ballast) placed dircctly on the pcepared subgrade. 7he crushM rock should be covcral with a suitablo filter fabric, such es Mirofi 140N or cquivalenL The toe drain sltoulJ be placed prior to pincemmt of tlw berm fill and should have an oudct dmi�. If lhe top of the drain is located Lelow the acljacent soils,then a pedorated wnduit sliould be placedµithin thc rock and routal by gravity to drain. We recommend that the necd for a toe drain be revieNed during qie finnl deaign. If lhc synthetie liner is used,thc toe drain should not be nece:sary. It will be impon.�nt to compact thc face of tlw pond fill cmbnnkmcnts. This should be made explicit lo ihe contractor performing thc on site work. Uncompacted soils on ihe berm face will be more susceptible to erosion:uid sloughing. ' Outfsli Constructiun: 77ic pond nnd bcmi rnnstructcd as outlincd will achieve its low permcability by matcrial choice and Ihc construction sequrncing dcscribcd. The construction of Uic oulla pipine lhrough ihe bcrm could cause pmfercntial Flow paths, ns unifortn material pincement nnd wmpaction is more diflicule in tight arav such as imnch cxcavation. To compmsnte for this, wro recommcnd that bcntonitc be mixed Nitli Oic fill placed around the outlet pipe[a reduce sapage. 7'hc exact quanlity of bentonile should be detcmiined b.ucd on Wc material found in lhc fidd. Ty�ical mixturts for QN dcposits is I50 pounds of NELSON-COUVRETTE&ASSOCIA7E5, INC. NELSON-COUVRETTE 8 ASSOCfATES, INC. �FP-?_3--]9?6 12� 14 �C�6 49t 251CJ 86%: P.23