Recharge systems for protecting and enhancing groundwate

TOPIC 3
Modelling aspects and groundwater hydraulics 429
Figure 1. Steps followed in groundwater modeling
CONCEPTUAL MODELING
The conceptual model is our best understanding of groundwater flow in the aquifer. Generally more valid data were
made available to construct the model. The data were used to understand: (1) the extent of the aquifer, its location
and its boundaries,(2) the flow of water into and out of the aquifer, (3) behavior o the water levels, (4) variation in
the thickness and the depth of the aquifer and any confining strata,(5) the spatial variation of the coefficient of
the transmissivity and storage, (6) pumping test data and discharge of wells and its drawdown, (7) water level fluctuations
in the aquifer over a number of years, (8) the possible river base flows, (9) spring location and spring
flows, (10) information related to basic hydrogeology of region such as areas of interconnections between surface
and groundwater.
In order to show three dimensional picture and groundwater conditions a fence diagram (Fig. 2 ) from lithological
data has been prepared for the area.
For choosing the size and external boundaries, it was decided to consider the major recharge and discharge areas.
The central parts of the basin is effected by a major fault, which strikes parallel to Sujas river so that boundary condition
assigned to these nodes considered to be constant at primary stages of calibration (Dirichlet type of boundary
condition), but later it was decided to consider the influence of river and fault in the parameters. Fig. 3 illustrates
surface two dimensional conceptual model and conditions of input and output areas.
10 – 16 June 2005, Berlin ■ 5th International Symposium ■ AQUIFER RECHARGE ■ ISMAR 2005