−log10
|
|
|
ppm
|
parts per million
|
|
|
Q
|
discharge
|
m3 s−1
|
|
Q f
|
fracture flow discharge
|
m3 s−1
|
|
q
|
specific discharge or darcy velocity
|
m s−1
|
|
R
|
hydraulic radius
|
m
|
|
R (Rd)
|
recharge (direct recharge)
|
mm a−1
|
|
R
|
universal gas constant (8.314 J mol−1 K−1)
|
|
|
RC
|
root constant
|
mm
|
|
R d
|
retardation factor
|
|
|
R e
|
Reynolds number
|
|
|
rem
|
roentgen equivalent man (older unit of dose equivalent; 1 rem = 0.01 Sv)
|
|
|
S
|
entropy
|
J mol−1 K−1
|
|
S
|
sorptivity of soil
|
cm (min)−1/2
|
|
S
|
storativity
|
|
|
S
|
slope
|
|
|
S p
|
specific retention
|
|
|
S s
|
specific storage
|
s−1
|
|
S sp
|
specific surface area
|
m−1
|
|
S y
|
specific yield
|
|
|
SMD
|
soil moisture deficit
|
mm
|
|
STP
|
standard temperature and pressure of gases (0 °C, 1 atmosphere pressure)
|
|
|
Sv
|
sievert (unit of dose equivalent that accounts for the relative biological effects of different types of radiation; 1 Sv = 100 rem)
|
|
|
s
|
groundwater level drawdown
|
m
|
|
s
|
solubility
|
g (100 g)−1 solvent
|
|
T
|
transmissivity
|
m2 s−1
|
|
T
|
absolute temperature
|
K
|
|
TDS
|
total dissolved solids
|
mg L−1
|
|
TOC
|
total organic carbon
|
mg L−1
|
|
t
|
time
|
s
|
|
t 1/2
|
radionuclide half‐life
|
s
|
|
V
|
volume
|
m3
|
|
V
|
volt (electrical potential)
|
|
|
V s
|
volume of solid material
|
m3
|
|
VOC
|
volatile organic compound
|
|
|
VSMOW
|
Vienna Standard Mean Ocean Water
|
|
|
v
|
groundwater or river water velocity
|
m s−1
|
|
|
average linear velocity (groundwater)
|
m s−1
|
|
|
average linear contaminant velocity
|
m s−1
|
|
|
average linear water velocity
|
m s−1
|
|
WHO
|
World Health Organization
|
|
|
WMO
|
World Meteorological Organization
|
|
|
WMWL
|
World Meteoric Water Line
|
|
|
W(u)
|
well function
|
|
|
w
|
width
|
m
|
|
ZFP
|
zero flux plane
|
|
|
z (hydraulics)
|
elevation
|
m
|
|
z (chemistry)
|
electrical charge
|
|
Greek symbols
|
Symbol
|
Description
|
Units
|
|
α
|
aquifer compressibility
|
m2 N−1 (or
|
