Chemical dynamics and weathering rates of a carbonate basin Bow River, southern Alberta

Discharge is the dominant control on the TDS load of the Bow River; TDS varies inversely with discharge. Although discharge is the dominant control on concentration, the sources of ions in the river are atmospheric deposition and water/rock interaction. Atmospheric loading can be a significant source of some ions in the pristine headwaters of the river (e.g., 50% of K, 17% of SO4, 16% of Cl). In terms of water/rock interaction, the input of ions to the river is largely controlled by dissolution of carbonate and evaporite minerals. The chemical denudation rate for the Bow River at Banff is 678 kg/ha/a, or 1.50×108 kg of rock that is removed as dissolved load each year, in the low range for an alpine carbonate basin. An additional 11 kg/ha/a are removed as suspended load. A rock volume of 5.45×104 m3 is carried by the Bow River from Banff National Park each year.