using the dispersion-convection equation of groundwater pollution to obtain the
parameters characterizing aquifer characteristics.
② Test procedure
According to the layout principle of field tracer test holes and groundwater flow
direction, the plane layout of field tracer test is shown in Fig. 5.74. During the field
tracer test, chloride ion solution with a concentration of 2000 mg/L is injected, the
time of tracer injection is recorded, and the conductivity and chloride ion concentration in the observation well were monitored every 2 h for 166 h. The conceptual model of injection well profile and observation well profile is shown in
Fig. 5.75.
③ Calculation results
According to the hydrogeological conditions and tracer test process in the field, the
tracer injection adopts the pulse injection, and the solution of groundwater
dispersion-convection equation is:
cðx; tÞ ¼
DM
2An e
ffiffiffiffiffiffiffiffi
pDt
p
exp À
ðx À vtÞ
2
4Dt
"
#
expðÀktÞ
where DM is the injected volume of tracer (M), x is the distance between injection
well and observation well (L), A is the cross-sectional area of groundwater flow
(L
2 ), n e is the effective porosity, v is the velocity of groundwater flow (L/T) and k is
the decay rate (T
−1 ).
Injection well
North
Observation well
Groundwater flow direction
Fig. 5.74 Layout plan of field tracer test
306
5 Application Cases
parameters characterizing aquifer characteristics.
② Test procedure
According to the layout principle of field tracer test holes and groundwater flow
direction, the plane layout of field tracer test is shown in Fig. 5.74. During the field
tracer test, chloride ion solution with a concentration of 2000 mg/L is injected, the
time of tracer injection is recorded, and the conductivity and chloride ion concentration in the observation well were monitored every 2 h for 166 h. The conceptual model of injection well profile and observation well profile is shown in
Fig. 5.75.
③ Calculation results
According to the hydrogeological conditions and tracer test process in the field, the
tracer injection adopts the pulse injection, and the solution of groundwater
dispersion-convection equation is:
cðx; tÞ ¼
DM
2An e
ffiffiffiffiffiffiffiffi
pDt
p
exp À
ðx À vtÞ
2
4Dt
"
#
expðÀktÞ
where DM is the injected volume of tracer (M), x is the distance between injection
well and observation well (L), A is the cross-sectional area of groundwater flow
(L
2 ), n e is the effective porosity, v is the velocity of groundwater flow (L/T) and k is
the decay rate (T
−1 ).
Injection well
North
Observation well
Groundwater flow direction
Fig. 5.74 Layout plan of field tracer test
306
5 Application Cases