ESTIMATION OF TRANSIENT STORAGE PARAMETERS FROM A STREAM TRACER STUDY

摘要

A stream tracer study was conducted in a 320-m reach of Indian Creek in Philadelphia. The objective was to investigate the role of geomorphology in the transport and exchange of a conservative tracer. The study reach has three geomorphicaly distinct sub-reaches. The experiments were simulated using the transient storage model, whose parameters were estimated by nonlinear optimization. Sub-reach averaged parameters were generally different highlighting the role of geomorphology; parameters estimated from sub-reach 1 provided relatively poor predictions for sub-reaches 2 and 3. Three forms of objective functions were used. The ordinary least square resulted in good fit around the peaks of the breakthrough curves and a relatively poor fit for the tail. The converse occurred when a weighted least square objective function was used.