Sediment trap

Abstract

The present invention provides a sediment trap for the floor of a waterway with moving water. In a preferred embodiment the trap forms a “still water” layer wherein the movement of a layer of water substantially corresponding in depth to the height of the trap is slowed and/or stopped, allowing sediment to precipitate. Preferably the trap then gentles the water flow to minimize the accumulation of additional sediment. In a preferred embodiment, the trap includes a vertical wall having a height less than the depth of the water, and preferably a height of one foot. In one preferred embodiment, the sediment trap further includes a ramp portion having a length extending downstream from the top edge of the vertical wall downwardly toward the floor of the waterway. Preferably the ratio of the height of the vertical wall to the length of the ramp portion is between approximately 1:4 and approximately 1:8. In an alternate preferred embodiment, the trap includes a vertical wall portion made from a resiliently yielding material such as rubber sheet, plastic sheeting or a reinforced fabric weave.

What is claimed is:  
     
         1 . A sediment trap for the floor of a waterway where water moves downstream, comprising: 
 a) a vertical wall mountable to the floor of the waterway having a top edge and a height less than the depth of the water; and,    b) means attachable to said vertical wall for fixing said vertical wall in place on the floor of the waterway.    
     
     
         2 . The sediment trap of  claim 1  further comprising a ramp portion having a length extending downstream from said top edge of said vertical wall downwardly toward the floor of the waterway.  
     
     
         3 . The sediment trap of claim  1 .a) further comprising an anchoring weight mounted to said vertical wall and said ramp portion.  
     
     
         4 . The sediment trap of  claim 2  wherein the ratio of the height of said vertical wall and the length of said ramp portion is between approximately 1:4 and approximately 1:8.  
     
     
         5 . The sediment trap of  claim 4  wherein the height of said vertical wall is approximately one foot.  
     
     
         6 . The sediment trap of  claim 1  wherein said vertical wall has sufficient rigidity to impede the flow of water for its vertical height and resiliently yields when struck by a solid object.  
     
     
         7 . The sediment trap of  claim 6  wherein said vertical wall is made of a rubber sheet material, a plastic sheet material or a reinforced fabric weave  
     
     
         8 . A sediment trap system for a waterway having a floor and sides channeling flowing water downstream, comprising: 
 a) at least one sediment trap including a vertical wall portion mounted to the floor of the waterway, having a top edge and having a height less than the depth of the water;    b) wherein each said sediment trap defines a horizontal width across said vertical wall; and,    c) wherein a sufficient number of sediment traps are arranged in a line to provide a horizontal width approximately the width of the waterway.    
     
     
         9 . The sediment trap system of  claim 8  further comprising extension barriers extending from the ends of said line of sediment traps to the sides of the waterway.  
     
     
         10 . The sediment trap of  claim 9  where each sediment trap further comprises a ramp portion having a length extending downstream from said top edge of said vertical wall downwardly toward the floor of the waterway.  
     
     
         11 . The sediment trap of  claim 10  wherein the ratio of the height of said vertical wall and the length of said ramp portion is between approximately 1:4 and about 1:8.  
     
     
         12 . The sediment trap system of  claim 9  wherein the height of said vertical wall is approximately one foot.  
     
     
         13 . The sediment trap system of  claim 9  further comprising at least two horizontal lines of sediment traps forming a first tier of traps at a first location and a second tier of traps at a second location wherein the second location is downstream from the first location a distance where the elevation change in the floor of the waterway is approximately equal to the height of said vertical wall.  
     
     
         14 . The sediment trap system of  claim 13  wherein the height of said vertical wall is approximately one foot.  
     
     
         15 . The sediment trap system of  claim 14  wherein a plurality of tiers of sediment traps are installed in the waterway wherein the tiers are staggered such that one tier is installed for each one foot change in elevation of the waterway.  
     
     
         16 . A method of minimizing sediment accumulation in a flowing waterway, comprising the steps of: 
 a) installing a vertical barrier on the floor of the waterway wherein the barrier has a height less than the depth of the water;    b) forming a still water layer upstream of the barrier wherein the still water layer has a height approximately equal to the height of the barrier; and,    c) allowing a layer of moving water to flow over the still water layer and over the barrier.    
     
     
         17 . The method of  claim 16  wherein said vertical barrier has a height of approximately one foot.  
     
     
         18 . The method of  claim 17  further comprising the step of installing multiple tiers of vertical barriers across the waterway wherein one tier of barriers is installed at a distance where the waterway elevation has dropped one foot.  
     
     
         19 . The method of  claim 17  further comprising the step of gentling the layer of moving water flowing over the barrier with a downwardly sloping ramp.