Try to use something that floats in the water rather than on top, as surface tension and air currents can slow surface floats significantly. Enter all three times, add them up and divide by 3 to determine the average time taken to float your reach. Multiply the average water velocity times the average square feet of the stream cross section to determine cubic feet of water passing your site every second. This number is the actual volume of water flowing past your site each second. Water clarity is observed to determine if sediment or pollution is entering the stream above your site.
Cloudy water can be the product of natural or human use in the watershed.
In Alaska, many streams are naturally cloudy from glacial runoff. Algae may occur naturally in streams, however, there are many human activities which can stimulate the growth of algae in streams. When the ground is disturbed by human activity, iron eating algae may grow in streams, resulting in rust-colored algae blooms. Too much lawn or garden fertilizer applied close to a stream causes large green algae blooms. Foam or sheen present on the water surface may be natural or man-made.