NOAA/WDS Paleoclimatology - White River, Arkansas 281 Year Flow Reconstruction

A 281-year reconstruction of White River calendar year runoff at Clarendon, Arkansas, was developed from a regional average of nine tree ring chronologies in Oklahoma, Missouri, and Arkansas (including six post oak and three bald cypress chronologies). Inhomogeneity of the gaged runoff series prior to 1930 was detected with two independent double mass analyses, comparing the gaged data with Arkansas state average annual precipitation and the regional tree ring chronology average. The homogeneous runoff data from 1930 to 1980 were calibrated with the average tree ring data using regression. The variance of the reconstruction increases significantly during the twentieth century and may reflect climatic change and/or anthropogenic disturbances in the watershed. Years of surplus and deficit runoff are nonrandomly distributed in both the gaged and reconstructed series. This nonrandomness appears to be caused primarily by interannual persistence of runoff extremes, which may provide a basis for some improvement of probabilistic forecasts of annual runoff for the White River.