Streambank failures result in loss of land and increased stream sediment loads. Variably saturated flow models integrated with bank stability models are being used to predict bank failure; however, understanding of the level of soil characterization necessary to predict when seepage contributes to bank failure is needed. ROSETTA, a pedotransfer function, was used to estimate hydraulic parameters for various levels of soil data (from texture class to saturated hydraulic conductivity, Ks). A two-dimensional groundwater flow code, SEEP/W, was used to model a hypothetical streambank and estimate seepage velocity. Results suggested that Ks and/or percent clay measurements are necessary to adequately predict seepage. A layered bank was also simulated with several combinations of soil types. Results indicated that only one order of magnitude difference in Ks (equivalent to a resistance ratio of 10) may be necessary to induce perching and seepage from the top layer. This research suggested that, if a field reconnaissance is performed to locate streambanks susceptible to perching, Ks and/or bulk density measurements are necessary to indicate the presence of a restrictive layer.