Field Trip - Northern Guam Lens Aquifer Jun 2014 | Page 6

The Northern Guam Lens
Aquifer: Water Processes

The Northern Guam Lens
Aquifer: Basic Facts

N

G

L

➤

➤

➤

➤

A

Geographic extent
all of northern Guam
Total surface area
83 sq mi (214 sq km)
Average annual rainfall
~100 inches / year
467 million gallons per day
Estimated recharge
238 million gallons per day

➤ Current production

(million gallons per day)

GWA
30-36

1

➤ Number of production wells

150

120

DoD
~4

14

Private
<1

16

Information on the number of wells and production is from Guam EPA, Guam Waterworks
Authority Engineering Department, US Navy, and US Air Force. Information provided
for educational discussion only. Not to be used as authoritative reference for engineering,
planning, or legal purposes.
1

6

RA

IN

E

Ove
rl
flowand

E

(100s of feet)

Freshwater
PHREATIC ➤
ZONE
(<200 feet)

L

Eva

por
SOIL (0-1 ft)➤
atio
n
EPIKARST➤ Tra
nsp
(10s of feet)
ira
tion
Infi
VADOSE
ltra
tion
ZONE ➤
E

FA
L

E

V
per ados
(m
ont colat e
hs
to y ion
ear

Ph

rea

tic

CH

sto

rag

ern

al r

uno

ff

Va
fas dose
(m
inu t flo
tes
w
t

s)

RE

Int

oh

our

AR

ea

nd

GE
flow

s)

Overflow
Spring/Seep
Discharge

7