Regionalized drought flow hydrographs from a mature glaciated plateau

TLDR

The study derives drought flow hydrographs by extracting the lower envelope of |dQ/dt| versus Q for each basin, thereby eliminating time‑reference uncertainty and evapotranspiration effects. Boussinesq’s nonlinear groundwater flow model best fits the hydrographs, with parameters linked to drainage area and stream length, enabling drought flow estimation for ungaged sites.

Abstract

The drought or base flow characteristics of six basins in the Finger Lakes region are obtained by considering for each available record the lower envelope of | dQ / dt | as a function of Q , where Q is the flow rate. This procedure avoids the uncertainty regarding a proper time reference after each rainfall event, and it eliminates the effects of evapotranspiration. The results suggest that among several expressions, Boussinesq's nonlinear solution of free surface groundwater flow is best suited to parameterize the observed hydrographs. The obtained parameters can be related to the basin characteristics, viz., drainage area and the total stream length, in accordance with relationships derived on the basis of the Dupuit‐Boussinesq aquifer model. This result allows the determination of drought flow parameters for ungaged sites within the region.