Mean Water Surface Elevation of Coast is the height, in relation to mean sea level of floods of various magnitudes and frequencies in the floodplains of coastal or riverine areas. And is denoted by η'o. Mean Water Surface Elevation of Coast is usually measured using the Meter for Length. Note that the value of Mean Water Surface Elevation of Coast is always negative. Typically, the value of Mean Water Surface Elevation of Coast lies in the range from -100 to 100.