The quality of water in mine pit lakes depends in part on the physical limnology, including such factors as thermal and chemic6l stratification, turnover and the development of anoxic conditions with depth. Limnologic data collected from four existing pit lakes in Montana and Saskatchewan indicate that pit lakes develop a thermo cline (temperature stratification) in the upper 10 to 30 m (33 to 100 ft) of the water column. Two of the pit lakes, 26- and 55-m (85-and 180-ft) deep, undergo seasonal turnover of the entire water column, whereas two deeper pit lakes, 110- and 240-m (360- to 790 ft) deep, undergo seasonal turnover of only the upper portion of the water column. In the deeper lakes, seasonal mixing does not extend through the entire water column, and a distinct chemo cline develops with depth.
展开▼
