nibw superfund site integration of groundwater extraction with a superfund remedy
TRANSCRIPT
NIBW Superfund Site
Integration of Groundwater Extraction
with a Superfund Remedy
What is the NIBW Site?
Deep, alluvial groundwater basin8 square mile site in urban settingExtensive groundwater contamination in
multiple units with complex hydrogeologyListed on NPL in 1983 with EPA lead Multiple PRPs, regulators, water providers
and other stakeholders
CamelbackMountain
PapagoButtes
Sc
ott
sd
ale
Ro
ad
Pim
a R
oa
d
Chaparral Road
ProductionWells
CamelbackMountain
PapagoButtes
Sc
ott
sd
ale
Ro
ad
Pim
a R
oa
d
Chaparral Road
Motorola
Siemens
MRTF
CGTF
RemediationActivities
NIBW Area “Facts of Life”
Many groundwater producers/users Conflicting water rights and competing interestsHistorical pumping for drinking water and
irrigation usesWide-spread groundwater depletion and
inorganic impactsContaminant occurrence/movement a result of
groundwater pumping and wells
Integrating Remediation with Groundwater Resource Management
Partner with groundwater users Utilize existing wells, infrastructure, and groundwater
pumping Coordinate groundwater extraction for optimum plume
management Build-in versatility of treatment systems to meet needs of
water users and their demands Manage other water resource issues
Wide-spread groundwater depletion and inorganic impacts
Big 3 Groundwater Producers
City of Scottsdale Local water provider for municipal end use Tied into OU-1 Remedy (required to pump > 6,300 gpm)
Paradise Valley Water Company (AAWC) Local water provider for municipal end use Small private water company owned by AWWSC Well field north of Site is main source ( > 12,000 gpm capacity)
Salt River Project Regional water provider for municipal/agricultural end use Export groundwater from Scottsdale to West Valley Impacted water supply wells ( > 6,000 gpm capacity) augment
surface water supply
COS Pump and Treat System
Expanded pump and treatment capacity to meet demands
Conducted detailed evaluation of fluid flow and contaminant distribution in production wells
Replaced existing well for enhanced LAU mass capture
Prioritized well pumping/increased monitoring frequency
Upgraded treatment system to facilitate use of priority wells and assure safe drinking water
Aided evaluation of nitrate and hardness impacts
Central Groundwater Treatment Facility (CGTF)
5 existing supply wells 9,450 gpm capacity 3 phases of plant
modifications: 1995/98/00 Potable water source 10+ MGD treatment 4,000 + lbs/year TCE
removal
Paradise Valley Initiative
Public/private partnershipPhased construction decision processDetailed hydrogeologic characterization
tied to remedial designConstruction on accelerated scheduleActive community participation
Arizona-American Water CompanyMiller Road Treatment Facility
6,300 gpm capacityVersatile piping, plant
operations, controls, and discharge
Potable water to PVWC and SRP
Unique cooperation and water exchange
Salt River Project Agreement
Provided water supply via NIBW and M52 remedy to replace impacted wells NIBW Pump and Treat Systems (4,000 gpm) OU-2 Pump and Treat System (~ 5,400 gpm)
Prioritize well use to achieve better capture/minimize impacts to clean wells
Achieves reduced pumping in NIBW and reliable end use at M52
Northern LAU Plume Management
Focused/consistent groundwater extraction for greatest mass capture
Optimize use of treatment system to meet variable demands
Reduced pumpage of clean wells outside the plume to minimize impacts and assure containment
Allows conjunctive use of surface water to reduce groundwater pumpage of basin
LegendAAWC Wells
COS Wells
SRP Wells
AWC Wells
Indian School Road
Camelback Road
Chaparral Road
Pim
a R
oa
d
Sc
ott
sd
ale
Ro
ad
McDonald Road
LAUPLUME
Northern LAU Plume
Containment
LegendAAWC Wells
COS Wells
SRP Wells
AWC Wells
Indian School Road
Camelback Road
Chaparral Road
Pim
a R
oa
d
Sc
ott
sd
ale
Ro
ad
McDonald Road
COS-75A LAU Only
COS-75Abandoned
PCX-1LAU Only
Miller RoadMiller RoadTreatmentTreatment
FacilityFacility
PVWC Water Supply
MRTF
PVWCEnd UseWells
PVWC
PVWCCAP Water3,200 AF/yr
9,600 AF/yrCapacity
10,600 AF/yr(6 wells)
PVWC/SRP Water Exchange
MRTF
PVWCEnd UseWells
PVWC
PVWCCAP Water3,200 AF/yr
9,600 AF/yrCapacityPCX-1
(SRP Well)3,200 AF/yr
SRPEnd Use
10,600 AF/yr
1,000 KAF/yr
CAP/PCX-1 Water Exchange
MRTF
PVWCEnd UseWells
PVWC
PVWCCAP Water3,200 AF/yr
9,600 AF/yrCapacityPCX-1
(SRP Well)3,200 AF/yr
SRPEnd Use
10,600 AF/yr
1,000 KAF/yr
(Reduced pumping)
(via Interconnect Facility)
Lessons Learned
Cooperation and coordination with all Stakeholders is essential
Expedite source control actionsEnd-use issues are critical Solutions require long-term vision Build-in versatility and flexibility Groundwater resource management must drive
the remedy