6.6. SR 03-15-2010 - Laserfiche WebLink

Home Browse Search

~ ReviewComments an the Revised Hydrageo Report phase z and ~z) and phase z~~~hase ~v work P1an.t~ dawn- rad~ ent ort~ ans of the s~ te. A11 three of the bore ngs show the occurrence of p sand ayers,,previous1 not shown on cross sections at these locations, which are present ~wi the n the ~~ 1 These sand layers lead to questions regards ng the cant~nu~ty of the t~11 layer and potential connection between the upper and lower outwash units. Cross~Section A-A` ~Addi ti ona1, data from P~l.g~ i ndi cafes the occurrence of two significant sand 1 ayers w7 the n the 1711. The upper sand 1 aver ~91~~ to 919} carrel ates , wi th a sand layer shown for s~n32. The lower sand layer ~8~9-9g5~ is ~.~ feet thick. eased an the 1 aver ti 11 contact el evat~ nns for s~ , ~~. and ss~~~ , there i s a patenti al to ~ i nterpret the twv sand 1 ayers to be ~ n connects on with the upper Qutwash unit far the s porti an of the site . gross-~sect7on ~-B' The additional data co11 ected far p~~SL adds si ni f i cance to the 1 i th~1 agi c interpretation for borings sg~~ , s~16 and s~-~.7 w i ch shows a si ~ni fi cant sand layer ro 1 be w en ~9Q n ~. or the e borin s. The sand 1a er d~ s dawn to the east ughy to ad96f s g y p and west of sg1~ w~ th a trend that could potent al l y 7 ntersect the 1 awer outwash unit. This sand layer may be connected to the sand layers shown in cross-section A~A' ith he o en i h e lower outwash units are connected to farm w t p t t al t at the upp r and a groundwater flout pathway. Cross-section G~G' The 1 i thol a~i c data for ~~.7~, shows the occurrence of two sand seams ~9Q7-9~.~ and 8$1w~97~ wi thz n the ti l 1. A si gn7 fi cant sand 1 ayer X893-~9a2~ i s shown far ss3~ further to the south. There is a strong potential far these sand 1a ere to be connected, although the cross~sectian does not show this. There is a.sa a potential that the lower sand seam could be Connected to the lower outhwash unit. The information from the additional deep borings shows the comp?exity of the geology and potential 1 ack of Conti nui ~y i n the ti 11 confi ni n layer i n the south and west portions of the site. wydraul~c cannect~on between t e upper and lower outwash units i s not supported by water l e~rel mani Lori ng 1 nformati on far nested veal 1 s , The water 1 eves dada show a verb eat head di f~erence of a proxi motel y ~. 5 feet between the outwash units at all laeations far th7s area of t e site. cross section ~~w' has been redrawn to show discontinuity in the outwash and a groundwater flow boundary 1c~cated between 5~~~ and sBT9. Figures 17, ~g and 2fl should be revised to shave the extension of the f1 aw boundary further to the east i n the northwest area of the SaA. secti an ~ .0 discusses the monitoring we11 s proposed for ~~he compliance boundary of the SDA. ~i ty of ~1 k River comments of Ma 1.1, ~po~4 i denti f'i ed the concern regarding the proposed distance of the wet S Pram the fi 11 1 i mi t during the earl years. of operation. The City suggested that a sequenced approach be taken fort e compliance ba~ndary and the p1 acement of compliance boundary wells cal nci di ng with the ~.O~year f~ 1 ~ 1 ~ m7 t. . MpCA correspondence dated ~u1 y, Z~, ~00~ , Pram Cahn ~1 ks to Tarr Johnson of wM~ indicates that a phased approach will be used far the camp lance boundary. The City supports the MPCA in relocating proposed mon~tor~ng page ~,