4, 1990

r. Harkr. ark S n y d e rH a s t e M a n a g e m e n t o f N o r t h A « » ,C e n t r a l f t e g i o n ° T N o ' t h A m e r i c a , I n c .S u b j e c t :

M r . S n y d e r :

S i n c e r e l y ,

L a w m i l R I / F S

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B e c f c e rC h i e fS u p e r f u n d E n f o r c e m e n t Branch ( 6 H - E )

; Robert He)ton - p« cA s s o c i a t e s . I n c .

6 H - E O : : doc 10 4-3-90

G o i d e r Associate s inc.C O N S U L T . : < G E N G I N E E R S

March 28, 1990Our R e f : 9 0 3 - 2 2 2 3

M s . Monica C h a p a ( 6 H - E O )M o s l e y Road P r o j e c t C o o r d i n a t o rO k l a h o m a / N e w Mexi co E n f o r c e m e n t S e c t i o nU . S . Environmental P r o t e c t i o n A g e n c y , Region 61445 Ross AvenueD a l l a s , T e x a s 7 5 2 0 2 - 2 7 3 3S u b j e c t : M o s l e y Road S a n i t a r y L a n d f i l l R I / F S

Recommendations f o r M o n i t o r i n g W e l l L o c a t i o n sDear M s . C h a p a :

H e - have c o m p l e t e d i n s t a l l a t i o n o f t h e p i e z o m e t e r s a n d l a n d f i l lborings that were p l a n n e d for the S o u r c e and P h y s i c a lC h a r a c t e r i z a t i o n ta sks under th i s R I / F S . T a b l e 1 p r o v i d e s al i s t o f the i n s t a l l a t i o n s c o m p l e t e d to d a t e . As part o f ourp h a s e d a p p r o a c h to s i t e c h a r a c t e r i z a t i o n at the M o s l e y RoadS a n i t a r y L a n d f i l l we are p r o v i d i n g our r e c o m m e n d a t i o n s for thel o c a t i o n s o f m o n i t o r i n g w e l l s and p u m p i n g w e l l s t o b e i n s t a l l e dd u r i n g th e C o n t a m i n a n t c h a r a c t e r i z a t i o n ta sk . T h e s e recommen-d a t i o n s are based on the p r e l i m i n a r y a n a l y s i s of water l e v e l sob ta ined f r o m p i e z o m e t e r s i n s t a l l e d r e c e n t l y a t t h e s i t e . T h e s ed a t a have a l l o w e d us to r e f i n e and u p d a t e the p r o p o s e d we l ll o c a t i o n s that were p r e s e n t e d in th e RI/FS W o r k P l a n . A l i s t i n gof the recommended m o n i t o r i n g and p u m p i n g w e l l s i s p r o v i d e d inT a b l e 2 . As p er t h e RI/FS W o r k P l a n we ar e s u b m i t t i n g t h i sl e t t e r to pre s ent our r e commendat i on s and to ob ta in EPAconcurrence on the p r o p o s e d l o c a t i o n s . W e l l i n s t a l l a t i o n workwas i n i t i a t e d on March 26, 1990.Based on our i n i t i a l review of water l eve l d a t a we are a l s op r o p o s i n g t o i n s t a l l one a d d i t i o n a l p i e z o m e t e r in to th e a l l u v i u mand o/ i« i a d d i t i o n a l p i e z o m e t e r into th e G a r b e r * - W e l l i n g t o n a q u i f e rt o f u r t h e r i d e n t i f y head c o n d i t i o n s . I n s t a l l a t i o n o f thesep i e z o m e t e r s w i l l b e c o m p l e t e d d u r i n g t h e f i e l d work i n i t i a t e don M a r c h 26.

OC

2 2 2 3 R E C W . P L R

s i t e . We have drawn p r e l i m i n a r y water level contours toi n d i c a t e general d i r e c t i o n s o f groundwater f l o w in the a l l u v i u mand G a r b e r - W e l l i n g t o n unit s . A l s o in c lud ed are d a t a taken inJ a n u a r y 1990 f r o m moni t or ing w e l l s that were i n s t a l l e d aroundt h e M o s l e y Road and East Oak L a n d f i l l s pr i or t o t h i s RI/FS. Wehave not had an o p p o r t u n i t y to take a new round of water l e v e l sf r o m these i n s t a l l a t i o n s as yet. It should be noted that thes i t e has exper i enced excessive p r e c i p i t a t i o n dur ing F e b r u a r yand ear ly March. As a r e s u l t , water l e v e l s in p o n d s and streamsare higher than normal. T h e r e f o r e , it is p o s s i b l e that as pondand stream l e v e l s f a l l to more normal value s and the amount ofdirect recharge to groundwater via i n f i l t r a t i o n decrea s e s , thegroundwat er l e v e l s may d r o p s l i g h t l y .The i n f o r m a t i o n pr e s en t ed in F i g u r e 1 i n d i c a t e s that there i sl i t t l e or no d i f f e r e n c e in water l e v e l s between the u p p e r andlower a l l u v i a l p i e z o m e t e r s . We see a s l i g h t downward g r a d i e n tin several l o c a t i o n s and a s l i g h t upward g r a d i e n t in others .It i s p o s s i b l e that these s m a l l v er t i ca l g r a d i e n t s in thea l l u v i u m ar e short term e f f e c t s f r o m th e recent h i g h r a i n f a l lat the s i t e . We have not encountered any s i g n i f i c a n t c o n f i n i n glayer s in the a l l u v i u m and we conc lude tha t it is a p p r o p r i a t eto treat the a l l u v i u m as one h y d r o g e o l o g i c un i t . The generalf l o w d i r e c t i o n in the a l l u v i u m i s f r o m south to nor th . Locald e v i a t i o n s in f l o w d i r e c t i o n occur near s u r f a c e water b od i e swhich intersect t h e a l l u v i a l water t a b l e . F o r i n s t a n c e ,g r o u n d w a t e r in a l l u v i u m f l o w s northeas t t owards C r u t c h o Creeka l o n g the eastern p o r t i o n o f the s i t e and f l o w s nor thwe s tt owards the N o r t h C a n a d i a n K i v e r in the area northwes t o f theEast Oak L a n d f i l l . The N o r t h Pond i s a p p a r e n t l y a l o ca lgroundwa t e r sink wi th a l l u v i a l g r o u n d w a t e r f l o w i n g in to i t f r o mboth the north and the south.

W a t e r l e v e l s in the G a r b e r - W e l i i n g t o n F o r m a t i o n , shown in F i g u r e2, are g e n e r a l l y lower than in the ov e r ly ing a l l u v i u m i n d i c a t i n gthat there i s a p o t e n t i a l for f l o w f r o m the a l l u v i u m to theG a r b e r - W e l l i n g t o n . T h e d i r e c t i o n o f f l o w i n t h e Garber-W e l l i n g t o n i s t owards t h e northeas t . D r i l l h o l e s p e n e t r a t i n gin to the G a r b e r - W e l l i n g t o n encountered a dense c l a y e y l a y e r atthe top of the G a r b e r - W e l l i n g t o n which p r o b a b l y acts as ac o n f i n i n g layer and accounts f or the d i f f e r e n c e s in water l e v e l sbetween the G a r b e r - W e l l i n g t o n and the o v e r l y i n g a l l u v i u m .PECOWMRMnAfT^w <—— - -Based on the

tooo

March 26, 1990 2 2 2 3 R E C W . P L R___903-2223

W e l l i n g t o n Format i on . A key reason for these a d d i t i o n a lpiezometer s is to determine whether the G a r b e r - W e l l i n g t o n isl o c a l l y d i s charging to Crutcho Creek,T h e s e piezometers would be i n s t a l l e d s t ar t ing on a p p r o x i m a t e l yMarch 26 assuming that su i tab l e access is ava i lab l e . T h e y wouldbe c o m p l e t e d in the same manner as the previous p i ezometer si n s t a l l e d a t the site during this RI/FS.R E C Q M M E T O & T I Q N S F Q R J M Q M I T Q R I N G . WELL L O C A T I O N SWe have revised the monitoring well network f r o m that o r i g i n a l l ypresented in the RI/FS Work Plan based on the d a t a obtained f r o mthe piezometers . The revised locat ions are shown in F i g u r e 3.In l i g h t of the downward gradient s measured between the a l l u v i u mand the G a r b e r - W e l l i n g t o n F o r m a t i o n we consider it necessary toi n s t a l l add i t i ona l w e l l s into th e G a r b e r - W e l l i n g t o n . A l s o ,based on the lack of any s i g n i f i c a n t g e o l o g i c a l or h y d r a u l i cd i f f e r e n c e s between the upper and lower a l l u v i a l zones we arenot p r o p o s i n g to in s ta l l s eparat e u p p e r and lower a l l u v i a lmonitor ing w e l l s .The locat ions f o r 2-inch diameter G a r b e r - W e l l i n g t o n moni tor ingw e l l s inc lude one upgradi ent well south of the s i t e , one wella l o n g the eastern boundary of the l a n d f i l l , one well a l ong thewestern boundary of the l a n d f i l l , two w e l l s a l ong the northernboundary of the l a n d f i l l , and two w e l l s l o c a t e d north of thel a n d f i l l a l ong 36 th S t r e e t . T h i s r e su l t s in a to ta l o f seven2-inch diameter G a r b e r - W e l l i n g t o n moni t or ing w e l l s .The l o ca t ions o f 2-inch diameter a l l u v i a l m o n i t o r i n g w e l l scorrespond to those of the G a r b e r - W e l l i n g t o n w e l l s with thea d d i t i o n of one well a long the eastern boundary of the l a n d f i l l ,two w e l l s a l o n g the southern boundary of the l a n d f i l l , two w e l l salong the northern boundary of the l a n d f i l l , and one wel lnorthwest o f th e l a n d f i l l . A l l u v i a l w e l l s w i l l b e screenedacross the entire a l l u v i a l section based on the observation thatthe a l l u v i u m acts as a s i n g l e h y d r o g e o l o g i c a l unit . A to ta l ofthirteen 2-inch diameter a l l u v i a l moni tor ing w e l l s arerecommended. Five o f these w e l l s would r e p l a c e e x i s t i n gmonitoring w e l l s around the l a n d f i l l . T h e s e w e l l s are beingreplaced because they were not i n s t a l l e d using the same wellde s ign and equivalent QA/QC being used f or thi s RI/FS.Wa o r i g i n a l l y proposed to in s ta l l one large d i a m e t e r ( e . g . 5inch) a l luv ia l well south of the l a n d f i l l and to conduct a pumpcast in it to determined large- s ca l e a q u i f e r parameter s . Basedon our evaluation of recent water level data we now considerthat a large diameter well in the G a r b e r - W e l l i n g t o n F o r m a t i o nmay also be needed to better characterize the large-seal©

Colder Associate s

March 26, 1990 2 2 2 3 R E C W . P U *903-2223

a q u i f e r parameters o f this unit. The t entat ive locat ions forthese we l l s are shown in Figure 3 as being south of the l a n d f i l lnear a piezometer cluster. T h i s would a l l o w monitoring of thepump test response in the p i ezometer s . However , the o p t i m u mlocations of these p u m p i n g w e l l s , if they are needed, are as yetundetermined because we have not had an o p p o r t u n i t y toadequate ly evaluate the geological data co l l e c t ed duringd r i l l i n g and s a m p l i n g of the piezometers. We need to determinethe geological variation of the a l luv ium and G a r b e r - W e l l i n g t o nunits across the site and then f i n a l i z e p u m p i n g well l o ca t i on sto target an area considered most representative of the areaswhere extraction w e l l s may be needed if it is determined thats i g n i f i c a n t c on taminat i on o f the a l l u v i u m a n d / o r Garber-W e l l i n g t o n has occurred. T h e r e f o r e , we propose to d e l a yf i n a l i z i n g p u m p i n g well l o c a t i o n s until l a t e r dur ing t h eContaminant Charac t er i sa t ion work.The revised monitoring well program described herein w i l l resultin a total of twenty 2-inch monitoring w e l l s seven of which w i l lbe c ompl e t ed in the G a r b e r - W e l l i n g t o n , and p o t e n t i a l l y two 5-inch diameter p u m p i n g w e l l s one of which w i l l be c o m p l e t e d inthe G a r b e r - W e l l i n g t o n . Two a d d i t i o n a l p i e z o m e t e r s w i l l a l s o bei n s t a l l e d one of which w i l l be c ompl e t ed in the Garber-W e l l i n g t o n . T h i s would result in a net increase in the t o ta lnumber of i n s t a l l a t i o n s f rom that o r i g i n a l l y s p e c i f i e d in theRI/FS Work P l a n . We consider these recommendations to bet e c h n i c a l l y sound based on the pr e l iminary d a t a c o l l e c t e d todate and request your concurrence.We look forward to continuing to work with the EPA on th i sp r o j e c t . P l e a s e contact the unders igned i f there are anyquestions regarding this matter.S i n c e r e l y ,GOLDER A S S O C I A T E S I N C .7J e r r y W. Rowe, PEAssoc ia t e

Anthony Gardner/Robert M e l t o n , PRC EnvironmentalDavid Guier , WMNAMark Snyder , W M N ALisa S e g l i n , W M N ARich O ' H a r a , W M N A

G o l d e r A s s o c i a t e s

1141.*! PZ-14CA1114149 P2-139A3

f>Z-127A1 PZ-126A3!* 14*6 O 1146.67P2-135A3 3143.32

M W - 1 31146.90

BH-104

*BM-102BH-101

6ROUNDS T O H A G ET A N K S

' - 1 1 9 A 1 M4S.O6

MW-22114&42 MW-12547,63

1143,31P2-136A3 1143.32

MW-241140.42 V M H T S * LEYB, J / K J W O

VWER UV6L CON7OIW ICONTOUrt1NTTOWL E Q U A L S OWE FOOn

¥«IW UPVEtS ON NORTH POND. SOUTH SV*MP. ANDC m i T C H O C K e E K W E B g T 5 W ( E N O N 3 / 5 ^ S O : V « 7 E KI f i m « THt WWTTNC S*NO AND «R*S. WT WS

W A S T E M A N A G E M E N T O F O K L A H O M AM O S L E Y ROAD S A N I T A R Y L A N D F I L L W A T E R L E V E L S I N T H E A L L J W J MG o l d e r A s s o c i a t e s I n c

._-__._ *PT>ROX)M>»E LtXyOKJNOF BUWED

- APPROXIMATE U X A 7 X 3 M W «J«EDP57WXEUM P W X X J C T S P f > S U N E

PZ-137144.O1 W f f E R i E V a . MEASURED 3*2 J/W

7 74£ G W B S l - W E U J N G T O N VOTER

PZ-113̂ 1146.45L E V E L SI N T H E G A B B E R - W E L L I N G T O NF O R M A T I O N

W A S T E M A N A G E M E N T O F O K L A H O M AM O S L F Y ROAD S A N I T A R Y L A N D F I L L

C o l d e r A s s o c i a t e s I n c .

I f M C n \ t S A N D A N D O f W J H . OPERATIONP B O P F H T Y 80UNDA8Y L I N E S

CRUDE C«. WPfUNF- APPROXIMATE t D C A T X X OF BURIED

S O U H C f S tSW USOS 1OPOORAP«C M*PS. PMOIOQWPHQ K H O O t C W "L«fV

H^>- PROPOSED AU.UVUM PEZOMET^RA PROPOSED P U W W G WELL W G A R B E R - W E U U N G T O MACVER LOCATION TO 9E DETERMINED

1146 S W B E R - W E U J M G T O N W H T C TLtVEl. d

W A S T E M A N A G E M E N T O F O K L A H O M AM O S L E Y ROAD S A N I T A R Y L A N D F I L L

BDL W H J R

C o l d e r A s s o c i a t e s I n c . PROPOSED M O N t T O R f N GV t f E L L

V f t R C H 1g9oi*A% S H O W N P**9O3-g?gg -

TABLE 1I N S T A L L A T I O N S C O M P L E T E D T H R O U G H M A R C H 21 ,1990

Designation T y p e iln.it MonitoredPZ-107-GP Z - 1 0 8 - A 1P Z - 1 0 9 - A 3P Z - 1 1 1 - A 3P Z - 1 1 2 - A 1P Z - 1 1 3 - GP Z - 1 1 S - A 3P Z - 1 1 6 - A 1P Z - 1 1 8 - A 3P Z - 1 1 9 - A 1PZ-120-GP Z - 1 2 2 - A 3P Z - 1 2 3 - A 1PZ-124-GP Z - 1 2 6 - A 3P Z - 1 2 7 - A 1P Z - 1 2 9 - A 3P Z - 1 3 0 - A 1P Z - 1 3 2 - A 3P Z - 1 3 3 - A 1P Z - 1 3 S - A 3P2-136-A1PZ-137-GP Z - 1 3 9 - A 3P Z - 1 4 0 - A 18 H - 1 0 1B H - 1 0 2B H - 1 0 3B H - 1 0 4B H - 1 0 S8 H - 1 0 6

Piezome t e rPiezometerPiezome t erPiezome t erPiezometerPiezometerPiezome t erP i e z o m e t e rP i e z o m e t e rPiezome t e rPiezome t erPiezome t e rPiezome t e rPiezome t e rPiezome t erP i e z o m e t e rPiezome t e rPiezometerPiezome t e rPiezome t erPiezome t erPiezometerPiezome t erPiezometerP i e z o m e t e r

L a n d f i l l Borehol eL a n a f i l l BoreholeL a n d f i l l BoreholeL a n d f i l l BoreholeL a n d f i l l BoreholoL a n d f i l l Boreho l e

G a r b e r - W e f l i n g t o n F m .U p p e r A H u v i u mLower A l l u v i u mLower A l l u v i u mU p p e r A l l u v i u mG a r b e r - W e l l i n g t o n F m .Lower A l l u v i u mU p p e r A l l u v i u mLower A l l u v i u mU p p e r A l l u v i u mG a r b e r - W e l J i r t g t o n F m .Lower A l l u v i u mU p p e r A l l u v i u mG a r b e r - W e l l i n g t o n F m .Lower A l l u v i u mU p p e r A l l u v i u mLower A l l u v i u mU p p e r A l l u v i u mLower A l l u v i u mU p p e r A l l u v i u mLower A l l u v i u mU p p e r A l l u v i u mG a r b e r - W e l l i n g t o n F m .Lower A l l u v i u mU p p e r A l l u v i u m

N o n eL a n d f i l lL a n d f i l l

N o n eN o n e

L a n d f i l l

Comment s

C o m p l e t e d wi th Leachate RiserC o m p l e t e d w i th Leachat e Riser

C o m p l e t e d w i th L e a c h a t a Riser

March 1990 Page 1

G o l d o r A s s o c i a t e s903-2223

TABLE 2.P R O P O S E D A D D I T I O N A L I N S T A L L A T I O N S

Designat i on T y p e UnitMW-201MW-202MW-203MW-14R

MW-11RMW-12RMW-13RMW-15RMW-204MW-205MW-206MW-207MW-208MW-209MW-21 0

M o n i t o r i n g W e l lM o n i t o r i n g W e l lMonitoring WellMonitoring WellMonitoring WellMoni tor ing WellM o n i t o r i n g Wel lM o n i t o r i n g Wel l

Monitoring WellMonitoring WellMonitoring WellM o n i t o r i n g W e l lM o n i t o r i n g Well

Monitoring WellMonitoring Well

A l l u v i u mG a r b e r - W e i l m g t o r , F m .Garber-Wellington Fm.Alluvium

AlluviumA l l u v i u mA l l u v i u mA l l u v i u mAlluviumGarber-Wellington Fm.AlluviumAlluviumGarber-Well ington Fm.Alluv ium( S a r h f l r - W n i i i — .— <---

Comment s

Replac ement well f o r M W - 1 4Replac ement well f o r M W - 1 1Replac emen t well f o r M W - 1 2Replacement wall f o r M W - 1 3Rep la c emen t well f o r M W - 1 5

M W - 2 1 1M W - 2 1 2M W - 2 1 3

M W - 2 1 4M W - 2 1 5

M o n i t o r i n g W e dM o n i t o r i n g W e l lM o n i t o r i n g W e l l

M o n i t o r i n g W e l lM o n i t o r i n g W e l l

A l l u v i u mG a r b e r - W e l l i n g t o nA l l u v i u mG a r b e r - W e l l i n g t o n

P u m p i n g W e l lP u m p i n g W e l l A l l u v i u mG a r b e r - W e l l i n g t o n F m . 5-inch d i a m e t e r p u m p i n g well5-inch diameter p u m p i n g wel lG a r o e r - W e l l i n g t o n F m Addit ional p i ezome t er East o fC r u t c h o Creek

Addit ional p i e z o m e t e r East o fCrut cho Creek

PW-216P W - 2 1 7P Z - 1 4 1 - Q