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- f -�� -.�-''�_ +.� ��" �` =„,.`��= •K .�`��� ...�.�--�a ��.etz, �,r =,��c'�:a. 4'� Gi��”' �=�".a `..a�� � ""`�'� ss:ff <br /> T - $ -'� +i� Y�, .Y>�.w n"•i'.-}.. }i 5�>P, :�,' �� ����w � fn< -'" 3v ��s� ��, x�-,r,�wm'�+;��-n', <br /> a <br /> r1 <br /> \t <br /> C-,d;p�i <br />( SIERWP <br /> r... <br /> SES STANDARD OPERATING PROCEDURE <br /> r <br /> MONITORING WELL DESIGN AND CONSTRUCTION <br /> *yi <br /> Where]aussillic°. italiarlulatiun from pubi,shed Ianal unpublished rcl3uns is rcvicu•cc prior to <br /> installation of nionitilring wells. Relevant data includes highest and lowest anticipated ground <br /> water cirva!inns, agtsiicr materials, aquifer yield and contaminants expected. This inform ltiu11 <br /> is used to aid the field geologist tallier than to predetermine how the wells will br. constructed. <br /> well construction is based on site specgiccorr(Ill ic):Isand is determined In the field after discussion <br /> with the senior i±eolo,0st, <br /> Thr wells arc screened to munitorthe first water-bearing zone encountered. If higli ground <br /> water conditions exist tlae. Sop of the well screed ntay he set at static water level or below statin <br /> =viper level. <br /> Fifteen feel of well screen will be used In thf.wells(five feet above static ground writer and <br /> Len, feet below static water) unless a five loot clay layer is encountered. if a clay layer is <br /> encountered, it will be confirmed by sampling. 1 he sampling hole into t-'ae underlying confinfri,g <br /> layer will bo sealed with bcntoaite pellets and i' e well screen will tnnrainatc 0 to 1 foul ilao tine <br /> clay layer. When field observations indicate that low permeability materials are acting as an <br /> aquitard to prevent nlavetllent of contazninants fess screen may be used. <br /> Monitoring wells are constructed with flush-threaded.2-inch or 4-inch diameter, ,lotted <br /> I'VC.stainless steel or teflon well screen and PVC.stainless steel or tenon blank casing. Number <br /> 3 or 4212 sand is ascii in the annular space around the well screen. The sand is placed into the <br /> annular space around the well screen to approximately 2 ft above the top of tllc well screen. if <br /> high ground water conditions exist. the sand may be placed 0 to 1 ft above the top of tite well <br /> screen. Two feet of bentonite pellets are used.to separate the sand from the sanitary,sari?Ice seal <br /> Igroul). If b igh ground water conditions exist 1/ fl of bentonite i...ty be used to separate the sand <br /> from the sanilary surface seal. <br /> The grout(Porllar.d cement with approximately 3-596 bentonite powder)is poured Into tile <br /> z <br /> annular space above the bentonite prllets. If the surface seal is greater than 5 feet thick, grout <br /> h cnnsistlllg of cerllenl mixed with 3-51% bentonite powder will be tremlcd or pumped halo the <br /> i� <br /> SEI <br />