Method of shore protection

Abstract

A method of shore protection is provided which includes determining a required direction of travel of incoming waves to a shore or shore portion to protect the shore and locating at least one elongate reef ( 1 ) on the sea bed ( 2 ). The reef ( 1 ) is oriented at a pre-selected angle relative to an average or mode direction of travel of incoming waves (W) and having pre-selected dimensions selected to modify the direction of travel of incoming waves to the required direction after passing over the reef ( 1 ).

1 . A method of shore protection including determining a required direction of travel of incoming waves to a shore or shore portion to protect the shore and locating at least one elongate reef on the floor of a body of water adjacent to the shore, wherein the reef is oriented at a pre-selected angle relative to an average or mode direction of travel of incoming waves and/or has pre-selected dimensions selected to refract waves travelling thereover to modify the direction of travel of incoming waves to substantially said required direction after passing over the reef.  
     
     
         2 . The method of  claim 1 , wherein the reef is located so as to be angled relative to the average or mode direction of travel of the incoming waves at an angle between 5° to 80°.  
     
     
         3 . The method of  claim 1 , further including selecting between a reef having a convex, concave or linear profile along its length depending on the requirements for wave modification.  
     
     
         4 . The method of  claim 1 , wherein the reef provided has a front face generally oriented towards the incoming waves and a lee face generally oriented towards the shore, wherein the lee face is substantially shorter than the front face.  
     
     
         5 . The method of  claim 4 , wherein the lee face is substantially vertical and the front face extends downwardly forward from the lee face generally in the direction of the incoming waves.  
     
     
         6 . The method of  claim 5 , wherein the front face is selected from a convex, concave or linear surface depending on a required shape of waves travelling over the reef.  
     
     
         7 . The method of  claim 1 , further including selecting the orientation and/or dimensions of the reef using refraction and diffraction analysis.  
     
     
         8 . The method of  claim 7 , wherein the orientation of the reef is determined using statistical analysis.  
     
     
         9 . The method of  claim 1 , including providing a reef having a height above the floor of the body of water of at least one meter.  
     
     
         10 . The method of  claim 1  including locating a plurality of reefs adjacent to the shore and spaced apart along the shore until a required portion of the shore has at least one elongate member substantially adjacent to it.  
     
     
         11 . The method of  claim 1  further including locating a plurality of reefs adjacent to a shore portion, wherein the incoming waves pass over at least two of said reefs before reaching the shore and wherein the required wave direction modification is achieved cumulatively as the waves pass over the said at least two reefs.  
     
     
         12 . The method of  claim 1  including locating the reef in water having a depth substantially between 2 to 15 metres.  
     
     
         13 . The method of  claim 1  including providing a reef with a height above the floor of the body of water so that the reef does not emerge from the surface of the body of water at least during some tide conditions.  
     
     
         14 . The method of  claim 1  wherein the required wave direction is more closely perpendicular to the line of the shore than said average or mode direction of travel of the incoming waves.  
     
     
         15 . The method of  claim 1  including providing a reef having an interior filled with a particulate material.  
     
     
         16 . The method of  claim 14  including providing a reef having geotextile material containing the particulate material.  
     
     
         17 . A reef when provided for performing the method of  claim 1 .  
     
     
         18 . The reef of  claim 17 , wherein the elongate member is constructed from geotextile bags.  
     
     
         19 . The reef of  claim 18  containing particulate material.  
     
     
         20 . The reef of  claim 19 , wherein the particulate material is sand.