A SAND BYPASSING SYSTEM USING A JET PUMP

Abstract

All harbors and tidal inlets that are located in coastal areas have one characteristic in common-the need to bypass littoral materials that collect nearby. If natural harbors and tidal inlets are left unattended, bypassing will often occur naturally, but in the process, the harbor or inlet is usually rendered unfit for commercial or navigation purposes. Quite often, the inattention results in the total closure of the inlet. Therefore, at almost all harbor entrances and controlled tidal inlets, the natural bypassing must be augmented by secondary, usually mechanical, means. The customary technique for bypassing sand and maintaining harbors and inlets is the use of floating dredge equipment. This equipment is rugged, reliable, has been proved over and over, and appears to be irreplacable for many applications and locations. However, there are many locations and situations for which this floating equipment is not suitable and may, in fact, be detrimental or prohibitively costly. Waves of even moderate height, moderateto- high tidal excursion and currents, draft limitations, limited maneuvering area, and interference with normal navigation operations are examples of conditions which decrease the desirability and application of floating dredge equipment. Small volumes of material to be bypassed are an economic liability for the floating plant since mobilization and demobilization costs contribute extraordinarily to the unit cost for bypassing work.