Changes in the surface water of the Marais de Cygnes River, 1964 to 1998.

Abstract

Acid precipitation has been moving westward in the past few decades. One way of determiner the extent of acid precipitation IS to evaluate the acidification of surface water. This study compared current with past ratios of alkalinity (HCO,) to hardness (Ca+2 & Mg+l as a measure of the acidification of the Marais de Cygnes River in east-central Kansas. At low to moderate discharge, the ratio showed no significant change, but this study found a decrease at high discharge compared with the data from the 1960s. The ratio was lowest m March, June and November, and highest m August. A site Immediately downstream from Melvern Dam had consistently lower ratios tl1at a site located further downstream m the city of Ottawa.