Relating low‐flow characteristics to the base flow recession time constant at partial record stream gauges

Abstract

Base flow recession information is helpful for regional estimation of low‐flow characteristics. However, analyses that exploit such information generally require a continuous record of streamflow at the estimation site to characterize base flow recession. Here we propose a simple method for characterizing base flow recession at low‐flow partial record stream gauges (i.e., sites with very few streamflow measurements under low‐streamflow conditions), and we use that characterization as the basis for a practical new approach to low‐flow regression. In a case study the introduction of a base flow recession time constant, estimated from a single pair of strategically timed streamflow measurements, approximately halves the root‐mean‐square estimation error relative to that of a conventional drainage area regression. Additional streamflow measurements can be used to reduce the error further.