KIRTLAND AIR FORCE BASE ALBUQUERQUE, NEW MEXICO ...

SECTION 3
3.3.4 Groundwater Monitoring Wells
A total of 15 groundwater monitoring wells and 37 piezometers will be installed in 23 boreholes,
including 20 “nested” locations, where two wells will be installed in a single borehole. The 15 proposed
monitoring wells will be installed in the groundwater table (“A”) horizon, with an anticipated completion
depth of 510 ft bgs. Twenty-one of the 37 piezometers will be installed in the “B” horizon, with an
anticipated completion depth of 550 ft bgs. Sixteen of the 37 piezometers will be installed in the “C”
horizon, with an anticipated completion depth of 590 ft bgs. Of the 20 nested well locations, four
locations shall contain a groundwater table (“A”) and “B” horizon well and 16 locations will contain a
“B” and “C” horizon well. The number and location of the proposed wells were primarily selected to
define the nature and extent of the LNAPL and groundwater dissolved-phase contaminant plumes. Well
installation IDs and corresponding horizons are included on Tables 3-1 and 3-2. The 23 borehole/well
locations are shown on Figure 3-2. A schematic showing a well construction detail is included on Figure
3-3.
Monitoring well (“A” horizon) and piezometer (“B” and “C” horizon) construction will include the
following:
• Five “A” horizon wells installed within the lateral extent of the LNAPL plume will be
constructed using 4-inch diameter schedule 80 polyvinyl chloride (PVC) riser pipe and
stainless steel screen (25-foot length, 0.010 slot, 10 feet below and 15 above water table).
• Six “A” horizon wells installed outside the lateral extent of the LNAPL plume will be
constructed using 4-inch diameter schedule 80 PVC riser pipe and screen (25-foot length,
0.010 slot, 10 feet below and 15 feet above water table).
• One “B” horizon monitoring well will be constructed using 4-inch diameter schedule 80 PVC
riser pipe and screen (10-foot length, 0.010 slot).
• Four “A” and “B” horizon nested wells will be constructed using 3-inch diameter schedule
80 PVC riser pipe and screen (10-foot length, 0.010 slot).
• Fifteen “B” and “C” horizon nested wells will be constructed using 3-inch diameter schedule
80 PVC riser pipe and screen (10-foot length, 0.010 slot).
• One “B” and “C” horizon nested wells will be constructed using 3-inch diameter schedule
80 PVC riser pipe and screen (KAFB10632B) for the “B” horizon well (KAFB10632C) and
2-inch diameter schedule 80 PVC riser pipe and screen. Both wells will utilize 10-foot length,
0.010 slot screens.
Non-Nested Wells: Filter pack (sand) will be placed adjacent to the well screen followed by a fine sand
seal and bentonite chip seal. A cement/bentonite grout will extend from the bentonite chip seal to near
ground surface. Surface completions will be within steel flush-mount protective covers (manholes) with
gasketed bolt-down covers. A concrete surface seal will be placed around the manhole and will extend
from the cement/bentonite grout to ground surface. The bentonite chip seal will be hydrated in lifts using
a “clean” water source.
Nested Wells: Filter pack (sand) will be placed adjacent to the lowest nested well screen followed by a
fine sand seal. A bentonite chip seal will extend from the top of the fine sand seal to just below the screen
of the highest well. Filter pack and fine sand seal will be placed, as above, around the highest nested well.
A bentonite chip seal will then be placed on the fine sand seal followed by a cement/bentonite grout
Kirtland AFB June 2010
Groundwater Investigation Work Plan BFF 3-6