ER   HOLLOWAY
                        GARAGE
                CHEYENNE RIVER INDIAN RESERVATION
                     EAGLE BUTTE, SOUTH DAKOTA
                                                                 March 2009
ACCOMPLISHMENTS
•  Conducted Tier I investigation
•  Excavated 892 yd3 of PCS
•  Conducted Tier II investigation
•  Installed 5 MWs
•  Ground-water monitoring
EPA Region 8 performed this work in partnership with
the Cheyenne River Sioux Tribe and with contract sup-
port from Avanti Corporation.
PLANNED ACTIVITIES/
FUTURE STRATEGIES
•  Continuation of quarterly groundwater monitoring
  of all MWs for a period of one year to establish the
  predominate groundwater flow direction, quantify
  ground water impacts seasonally and monitor plume
  stability
  Evaluate the need for additional MWs and additional
  monitoring
  Coordinate excavation of off-site PCS during replace-
  ment of water lines
  Evaluate site closure
SITE  HISTORY
The Former Holloway Garage site had many for-
mer uses before it came under the ownership of the
Cheyenne River Sioux Tribe in 1998. The site had
been a car dealership, gas station and auto repair shop,
lumber yard, and used for storage. Two underground
storage tanks (USTs) were installed in 1966 and were
later removed in 2004. During removal, one of the USTs
was punctured by a backhoe and an estimated 500 gal-
lons of diesel fuel was released. During excavation of
the petroleum contaminated soil (PCS) resulting from
the 500 gallon release, additional extensive petroleum
contamination was discovered. A soil and groundwater
site investigation in 2005 lead to the removal of 892
cubic yards of contaminated soil. A Tier II site inves-
tigation was  conducted in 2007. Five monitoring wells
(MWs) were installed as part of the Tier II investiga-
tion. Confirmation soil samples collected following the
excavation of on-site PCS indicated that soil remaining
on-site is below Tier I levels. Groundwater monitoring
results indicate that groundwater beneath the site is
below action levels for all chemicals-of-concern.
TIME LINE


r Car dealership
began operations
	 Site converted to
a lumber yard

r Purchased by Cheyenne
River Sioux Tribe and used
as a storage site
	 Site vacated and all structures and
USTs removed • Excavation of con-
taminated soils in tank pit area
Additional PCS discovered on-site
and extending under Main Street




1 1926^-1945 ^1966 ^-1982 ^-1990^-1998^-2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 1
Site sold to 	 1 1 	 2 USTs installed •
Eagle Butte Site becomes a
Motor Company gas station and
auto repair shop
' — Tier II Investigation and
RBCA Assessment
5 MWs installed
	 Ti^r 1 Im/^cficra-Hnn a
,


                                                         892 yd3 PCS removed
         FORMER HOLLOWAY GARAGE
         EPA Region 8 UST Program Technical Contact | Mr. Raymond Faliskie | (303) 312-6124 orfaliskie.raymond@epa.gov | www.epa.gov/region8/ust/

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