SUSPENDED LOAD. (1) The material moving in suspension in a fluid, kept up by 

 the upward components of the turbulent currents or by colloidal 

 suspension. (2) The material collected in or computed from samples 

 collected with a SUSPENDED LOAD SAMPLER. Where it is necessary to 

 distinguish between the two meanings given above, the first one may be 

 called the "true suspended load." 



SUSPENDED LOAD SAMPLER. A sampler which attempts to secure a sample of the 

 water with its sediment load without separating the sediment from the 

 water. 



SWALE. The depression between two beach ridges. 



SWASH. The rush of water up onto the beach face following the breaking of a 

 wave. Also UPRUSH, RUNUP. (See Figure A-2.) 



SWASH CHANNEL. (1) On the open shore, a channel cut by flowing water in its 

 return to the present body (e.g., a rip channel). (2) A secondary channel 

 passing through or shoreward of an inlet or river bar. (See Figure A-9.) 



SWASH MARK. The thin wavy line of fine sand, mica scales, bits of seaweed, 

 etc., left by the uprush when it recedes from its upward limit of movement 

 on the beach face. 



SWELL. Wind-generated waves that have traveled out of their generating 

 area. Swell characteristically exhibits a more regular and longer period 

 and has flatter crests than waves within their fetch (SEAS). 



SYNOPTIC CHART. A chart showing the distribution of meteorological conditions 

 over a given area at a given time. Popularly called a weather map. 



SYZYGY. The two points in the Moon's orbit when the Moon is in conjunction or 

 opposition to the Sun relative to the Earth; time of new or full Moon in 

 the cycle of phases. 



TERRACE. A horizontal or nearly horizontal natural or artificial topographic 

 feature interrupting a steeper slope, sometimes occurring in a series. 



THALWEG. In hydraulics, the line joining the deepest points of an inlet or 

 stream channel. 



TIDAL CURRENT. See CURRENT, TIDAL. 



TIDAL DATUM. See CHART DATUM and DATUM PLANE. 



TIDAL DAY. The time of the rotation of the Earth with respect to the Moon, or 

 the interval between two successive upper transits of the Moon over the 

 meridian of a place, approximately 24.84 solar hours (24 hours and 50 

 minutes) or 1.035 times the mean solar day. (See Figure A- 10.) Also 

 called lunar day. 



TIDAL FLATS. Marshy or muddy land areas which are covered and uncovered by 

 the rise and fall of the tide. 



A-35 



