  A modified version of a published slug test model for unconfined aquifers is
applied to cross-hole slug test data collected in field tests conducted at the
Widen site in Switzerland. The model accounts for water-table effects using the
linearised kinematic condition. The model also accounts for inertial effects in
source and observation wells. The primary objective of this work is to
demonstrate applicability of this semi-analytical model to multi-well and
multi-level pneumatic slug tests. The pneumatic perturbation was applied at
discrete intervals in a source well and monitored at discrete vertical
intervals in observation wells. The source and observation well pairs were
separated by distances of up to 4 m. The analysis yielded vertical profiles of
hydraulic conductivity, specific storage, and specific yield at observation
well locations. The hydraulic parameter estimates are compared to results from
prior pumping and single-well slug tests conducted at the site, as well as to
estimates from particle size analyses of sediment collected from boreholes
during well installation. The results are in general agreement with results
from prior tests and are indicative of a sand and gravel aquifer. Sensitivity
analysis show that model identification of specific yield is strongest at
late-time. However, the usefulness of late-time data is limited due to the low
signal-to-noise ratios.
