Water science news, explainers, and statistics covering freshwater, hydrology, lakes, rivers, groundwater, ice, and Earth’s connected water systems.
Lakes freeze from the top down because winter removes heat at the air-water boundary and freshwater becomes less dense after it cools below about 4°C. The coldest liquid remains near the surface, reaches its freezing point and forms ice there. The deeper water can stay liquid beneath the new cover. Floating ice then slows further…
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Wisconsin does not publish one official ranking of its “cleanest” lakes. State records do identify exceptionally clear, low-algae lakes, including Black Oak Lake in Vilas County and Lake Owen in Bayfield County. A defensible comparison uses recent multi-year summer Secchi transparency or chlorophyll-based trophic status and compares lakes of similar natural type. Under that method,…
Oklahoma has no official “cleanest lake” ranking. State monitoring does, however, identify lakes with low turbidity, deep Secchi visibility or relatively low algal productivity during specific survey periods. Broken Bow, Sooner, Carl Albert and Sportsman are among the stronger documented examples in the Oklahoma Water Resources Board lake report, but they cannot be ranked as…
Maine’s official lake-depth charts are collected in the Department of Inland Fisheries and Wildlife Lake Survey Maps directory. Search by water name, town or county, then open the survey sheet for contours, access points and fishery information. Maine DEP’s lake-data mapper can add monitoring stations and environmental context. The charts are valuable general references, especially…
