Freeboard means a factor of safety usually expressed in feet above a flood level for purposes of floodplain management. "Freeboard" tends to compensate for the many unknown factors that could contribute to flood heights greater than the height calculated for a selected size flood and floodway conditions, such as wave action, blockage of bridge or culvert openings, and the hydrological effect of urbanization of the watershed.
Grease means an organic substance recoverable by procedures set forth in Standard Methods and includes but is not limited to hydrocarbons, esters, fats, oils, waxes, and high molecular weight carboxylic acids.
Slash means all debris created on the Work area by the precommercial thinning operation.
Drum means any cylindrical metal shipping container of 13 to 110 gallon capacity.
Grab means an individual sample collected at such time and location as to be representative of the discharge.