This report concerns one aspect of the marina permit evaluation process: water quality impacts related to marina circulation and flushing efficiency. These physical properties vary with the wind, tide range, water density, and physical dimensions of a marina. Water quality is affected by the degree of flushing, and sediment redistribution by currents. Detrimental water quality can determine the fate of migrating juvenile fish and benthic organisms. Hydraulic model studies of small harbors provide an alternative method of assessing flushing ability.