|
I I I
<br /> I
<br /> CLEARWA'TER
<br /> G R O U P, I N C
<br /> '
<br /> 30 CT'IVI FIELD A TIES l
<br /> All work was performed in accordance with Clearwater Field Proceedures
<br /> (previously submitted) and under the directives and guidelines established by the
<br /> PHS/EHD and the Regional,Water Quality Control Board
<br /> The monitoring wells were gauged and sampled on December 28, 1994 Prior to
<br /> sampling, all wells were purged of a minimum of three saturated well volumes
<br /> 1 Well purging information is presented in Appendix A The monitoring wells were,
<br /> resampled on January 4, 1995, after the project courier failed to keep the samples
<br /> adequately cool In accordance with instruction from the PHS/EHD, no additional
<br /> ' gauging or purging data was generated at this time
<br /> Groundwater samples were collected from the monitoring ,wells using dedicated
<br /> polyethylene bailers Samples were labeled, documented on a chain-of-custody
<br /> Y form, and placed in a cooler for transport to PACE, Inc (PACE), a DHS-certified
<br /> laboratory located in Novato, California All groundwater samples were analyzed
<br /> for total petroleum hydrocarbons as gasoline (TPHg) by EPA Method 8015
<br /> (modified), and for benzene, toluene, ethylbe'nzene and total xylenes (BTEX) by EPA
<br /> Method 8020 (modified)
<br /> I I
<br /> 4.0 RESULTS AND DISCUSSION
<br /> I I " � I
<br /> 4.1 Water Level Monitoring Data
<br /> �° II
<br /> I I ,
<br /> On December 28, 1994,,the depth to ground water in each of the wells ranged from
<br /> 27 81 to 29.13 'feet below , grade Groundwater flow was determined to be
<br />` northwesterly at an approximate gradient of 0 031 foot/foot across most of the site
<br /> ' In the northwest corner of the site, downgradient of the former tank excavation, the
<br /> groundwater flow was to the northwest at an approximate gradient of' 0 013
<br /> foot/foot. Plotted on the ,Groundwater Contour Map I (Figure 3) this change in
<br /> "gradient appears,as a'slight mounding of the water table' u1 the vicuuty of the former
<br /> 1
<br /> USTs r A simi"l"ar groundwater mound was apparent in,the same location�duruig the
<br /> ! previous gauging'evr ent
<br /> litei S I '
<br /> , 1 , I o
<br /> The site is unpaved; therefore itis,likelyrtAat; groundwater recharge through the
<br /> I l r a ' I III I 1 I i' ' I I ; ' I,'; r 4 1 I 1 I ' I ! I
<br /> vadose 'zone,is''producing,1al cistern-effect'Ein' porous excavation',,backfill' !mater`ial,!`I! 1
<br /> causing, this" mound featur'e!;I` The mounding will continue toI Ibe monitored 'in
<br /> ' future gauging events, and I`the results of these- observations !documented in
<br /> subsequent reports
<br /> 11lFI }tNI I I
<br /> I D-1 OL 4Q941 i hr ��' 2 I February"15' 1995,
<br /> I I fl au " l r W Ij rl
<br /> I Ili ,rrn , t y I '
<br /> r r ,III "I 1 ll� I I f I''j I 1 it I. I ripy SII q l t rl + I Ir , idll l �� I
<br /> I�
<br /> ff'� i i {till I I r` ,, IIr111
<br /> `t1 h!I�I,gI,lk�€III II, ,i tlIJII��I�I ItI't''I a, s' I! Ii'I it I pl , EleEi '41 I �{ �r'f�Ifili'
<br />
|