Drilled shafts installed in lakes or rivers require use of a casing placed from above the water surface to a minimum embedment into the river or lake bottom. Define the top of the drilled shaft in water as 2 ft. typical above the normal water elevation. If the water level is variable, add a provision allowing the top of the drilled shaft to be adjusted vertically based on water level at the time of construction. If casing is to be left in place, disregard side resistance along the length of the casing. If permanent casing is used in standing water, consideration should be given to painting the portion of casing extending above the mud line.