Fig. 4. Observed and modeled breakthrough curves generated from the DML-3, SIDP-1, SIDP-2, and SIDP-3 columns, where DML is the Des Moines Lobe and SIDP is the Southern Iowa Drift Plain. The dashed vertical line for the DML-3 column indicates the time for one pore volume (PV) to pass through the column. The pore volumes were off scale for the SIDP-1, SIDP-2, and SIDP-3 columns.