Application of H₂¹⁸O/H₂¹⁶O Abundances to the Problem of Lateral Mixing in the Liard–Mackenzie River System

Relative H 2 18 O/H 2 16 O abundances were determined in 10 cross-sectional profiles of the Liard–Mackenzie River system sampled during June, 1970 at various intervals over 300 miles (480 km) distance downstream from their confluence. At their confluence, the Liard and the Mackenzie Rivers had average δH 2 18 O values of −21.3‰ and −17.4‰ SMOW respectively. Thus, lateral mixing of the two waters could be monitored isotopically. The data show that a distance of the order of 200 miles (320 km) was required for thorough lateral mixing.