Estimation of hydrogeological parameters using physically based hydrological modelling and lithology data in ungauged creek catchments of southern Taiwan

Streamflow recession analysis is widely used for estimating catchment-scale hydrogeological parameters in gauged catchments because of its low cost, ease of use, and efficiency in terms of results. In this work, however, the same methodology was applied to ungauged creek catchments, where low recession flows were simulated using physically based, semi-distributed, continuous hydrological modelling. Moreover, a combination approach was used to reasonably estimate the effective aquifer depth (D) with borehole lithology and digital elevation model data. The estimated hydraulic conductivity (k) values ranged between 10^–5 and 10^–3 m s^–1, and they were comparable with the results of a field test. By contrast, the specific yield (S_y) values obtained through streamflow recession analysis (10^–7 to 10^–5) were lower than the results of the field tests at different aquifer depths. However, the S_y values obtained for alluvial catchments (on the order of 10^–5) were comparable. Thus, the results of the comparison support the application of the streamflow recession analysis scheme for estimating hydrogeological parameters in ungauged creek catchments.