Abstract:
Pilot point methodology (PPM) permits estimation of transmissivity at unsampled pilot
points by solving the hydraulic head based inverse problem. Especially relevant to areas with
sparse transmissivity data, the methodology supplements the limited field data. Presented herein
is an approach for estimating parameters of PPM honoring the objectives of refinement of the
transmissivity (T) interpolation and the model calibration. The parameters are the locations and
number of pilot transmissivity points. The location parameter is estimated by defining a qualifying
matrix Q comprising weighted sum of the hydraulic head-sensitivity and the kriging variance fields.
Whereas the former component of Q promotes the model calibration, the latter one leads to improved
T interpolation by locating pilot points in un-sampled tracts. Further, a three-stage methodology is
proposed for an objective determination of the number of pilot points. It is based upon sequential
upgradation of the Variogram as the pilot points are added to the data base, ensuring its convergence
with the head-based optimal Variogram. The model has been illustrated by applying it to Satluj-Beas
interbasin wherein the pumping test data is not only sparse, but also unevenly distributed.
