Porous groin with flotation support

Abstract

An adjustably compliant porous groin and method for use in restoring an eroding shoreline. The compliant porous groin has a barrier suspended by flotation support within a sediment laden eroding water flow of the shoreline with the water flow passing through at least a portion of the barrier, and the bottom edge of the barrier retained proximate to the seabed. The barrier is compliant such that the water flow impacting the barrier is slowed whereby suspended sediment in the water flow accretes to renourish the shoreline.

What is claimed is:  
     
         1 . An adjustably compliant porous groin for use in restoring an eroding shoreline, the shoreline having a seabed, and the shoreline having an eroding water flow impacting thereon, the eroding water flow including suspended solids therein, the eroding water flow having a periodic high and low tidal surge, the compliant porous groin comprising: 
 a compliant porous barrier having a top edge and a bottom edge, the barrier being suspended by flotation support within the eroding water flow;    the barrier having the bottom edge retained proximate to the seabed; and    wherein the compliant porous barrier causes the accretion of the suspended solids from the water flow thereby restoring the eroding shoreline.    
     
     
         2 . The complaint porous groin of  claim 1 , wherein the compliant porous barrier is comprised of a flexible mesh.  
     
     
         3 . The compliant porous groin of  claim 1 , wherein the flotation support includes at least one float attached to the barrier top edge.  
     
     
         4 . The compliant porous groin of  claim 3 , wherein a tether line is attached to the float at one end, and is restrained to the seabed at the other end, such that the barrier top edge is suspended by the flotation support substantially at the height of mean low tide for all tide levels.  
     
     
         5 . The compliant porous groin of  claim 1 , wherein the flotation support includes at least one intermediate float attached to the barrier, between the barrier top edge and the barrier bottom edge.  
     
     
         6 . The compliant porous groin of  claim 1 , wherein a marker float is tethered to the compliant porous barrier.  
     
     
         7 . The compliant porous groin of  claim 1 , wherein the barrier bottom edge is retained proximate to the seabed by tethering to a seabed anchor.  
     
     
         8 . The compliant porous groin of  claim 1 , wherein the barrier bottom edge is retained proximate to the seabed by weighting the barrier bottom edge.  
     
     
         9 . The compliant porous groin of  claim 1 , wherein the barrier bottom edge is retained proximate to the seabed by: 
 a restraint tether attached at one end to the barrier bottom edge;    a restraint float attached at to an opposing end of the restraint tether;    the restraint tether slidably engaging a seabed anchor on the restraint tether between the attachment point of the barrier bottom edge and the attachment point of the restraint float; and    wherein a flotation force on the restraint float causes a tension in the restraint tether, the restraint tether sliding in the seabed anchor and pulling the barrier bottom edge towards the seabed.    
     
     
         10 . The compliant porous groin of  claim 1 , wherein the compliant porous barrier is also suspended by at least one stanchion.  
     
     
         11 . The compliant porous groin of  claim 1 , wherein the barrier is constructed from a material having a specific gravity in seawater between 0.9 and 1.1.  
     
     
         12 . The compliant porous groin of  claim 1 , wherein the barrier is constructed from a material having gas filled, sealed internal voids.  
     
     
         13 . An adjustably compliant porous groin for use in restoring an eroding shoreline, the shoreline having a seabed, the shoreline having an eroding water flow impacting thereon, the eroding water flow including suspended solids therein, the eroding water flow having a periodic high and low tidal surge, the compliant porous groin comprising: 
 a compliant porous barrier having a top edge and a bottom edge, the barrier being suspended within the eroding water flow;    the barrier having the bottom edge retained proximate to the seabed;    an extraction line attached at one end to at least the barrier bottom edge, and attached at the other end to an extraction float;    the compliant porous barrier causing the accretion of the suspended solids from the water flow thereby restoring the eroding shoreline; and    wherein the barrier bottom edge is elevated from the accreted solids by the periodic high tidal surge immersing the extraction float, and the extraction float pulling upward upon the extraction line.    
     
     
         14 . The compliant porous groin of  claim 13 , wherein the compliant porous barrier is suspended by flotation support.  
     
     
         15 . The compliant porous groin of  claim 13 , wherein the compliant porous barrier is suspended by at least one stanchion.  
     
     
         16 . The compliant porous groin of  claim 15 , wherein the compliant porous barrier bottom edge is slidably restrained to the stanchion.  
     
     
         17 . A method for restoring an eroding shoreline, the shoreline having an eroding water flow thereon and a seabed, the eroding water flow including suspended sediments therein and having a periodic high and low tidal surge, the method comprising the steps of: 
 placing a compliant porous barrier within the eroding water flow such that the barrier is suspended in the eroding water flow by flotation support, the barrier having a top edge and a bottom edge, the barrier bottom edge being retained proximate to the seabed, the barrier being adjustably compliant to the impacting water flow; and    accreting sediment from the eroding water flow wherein the compliant porous barrier causes the accretion of the suspended solids from the eroding water flow thereby restoring the eroding shoreline.    
     
     
         18 . The method of  claim 17 , further comprising a barrier lifting step for lifting the barrier out from the accreting sediment as sediment accretes from the water flow to cover the bottom edge of the barrier.  
     
     
         19 . The method of  claim 18 , further comprising: 
 an extraction line attachment step for attaching one end of an extraction line to at least the barrier bottom edge;    an extraction float attachment step for attaching the opposing end of the extraction line to an extraction float; and    a barrier bottom edge elevation step for elevating the bottom edge of the barrier from the accreting solids when the periodic high tidal surge immerses the extraction float and the extraction float pulls upon the extraction line.    
     
     
         20 . The method of  claim 17 , further comprising a removal step for removing the compliant porous barrier from the shoreline.  
     
     
         21 . The method of  claim 17 , wherein the step of retaining the barrier bottom edge proximate to the seabed comprises: 
 a restraint tether attachment step for attaching one end of a restraint tether to the barrier bottom edge;    a restraint float attachment step for attaching an opposing end of the restraint tether to a restraint float;    an engaging step for slidably engaging a seabed anchor on the restraint tether between the barrier bottom edge and the restraint float; and    wherein flotation forces on the restraint float cause a tension in the restrain tether, the restraint tether sliding in the seabed anchor and pulling the barrier bottom edge towards the seabed.    
     
     
         22 . A compliant porous groin for use in restoring an eroding shoreline, the shoreline having a seabed, and the shoreline having an eroding water flow impacting thereon, the eroding water flow including suspended solids therein, the eroding water flow having a periodic high and low tidal surge, the compliant porous groin comprising: 
 a compliant porous barrier having a top edge and a bottom edge, the barrier being suspended within the eroding water flow;    the barrier having the bottom edge retained proximate to the seabed by a restraint tether attached at one end to the barrier bottom edge, a restraint float attached at to an opposing end of the restraint tether, the restraint tether slidably engaging a seabed anchor on the restraint tether between the attachment point of the barrier bottom edge and the attachment point of the restraint float, a flotation force on the restraint float causing a tension in the restraint tether, the restraint tether sliding in the seabed anchor and pulling the barrier bottom edge towards the seabed; and    wherein the compliant porous barrier causes the accretion of the suspended solids from the water flow thereby restoring the eroding shoreline.