Small stream fish ladder

Abstract

A fish ladder for small-bodied fishes that is easily portable so as to enable installation and use in a given water course when needed, and relocation at other times. The fish ladder defines a channel with generally evenly spaced baffles in the channel disposed at about 45° angles to the channel bottom. The ladder includes a bracket that enables the ladder to be attached to any size, shape, and material of culvert or other drainage structure. The ladder is attached to the bracket with a hinge mechanism, so as to accommodate virtually any height of drop presented by small drainage structures. With extendable legs, a fish ladder according to embodiments of the invention is able to be installed in streams up to 6 feet deep. The ladder can be scaled so as to target passage of small-bodied non-game species such as minnows, while also passing larger game species as well.

What is claimed is: 
     
         1 . A fish ladder comprising:
 a structure interface adapted to attach to a drainage structure, the structure interface portion including a weir plate; and   a ladder defining a channel for conveying water in a flow direction, the ladder including a plurality of baffles disposed across the channel generally transverse to the flow direction, the ladder operably coupled to the interface structure with a detachable hinged connection.   
     
     
         2 . The fish ladder of  claim 1 , wherein the detachable hinged connection comprises at least one hinge pin receiver on the structure interface, the at least one hinge pin receiver defining a first bore, a pin receiving sleeve on the ladder, the pin receiving sleeve defining a second bore, and a hinge pin received through the first bore and the second bore. 
     
     
         3 . The fish ladder of  claim 2 , wherein the ladder is shiftable about the hinge pin between a first position in which the ladder extends in a horizontal orientation from the structure interface and a second sloped orientation in which the ladder slopes downwardly from the structure interface. 
     
     
         4 . The fish ladder of  claim 1 , wherein the channel is defined by a pair of spaced apart substantially parallel side panels and a bottom panel extending between the side panels. 
     
     
         5 . The fish ladder of  claim 1 , wherein the baffles are angled rearwardly toward the structure interface. 
     
     
         6 . The fish ladder of  claim 5 , wherein the baffles are angled at about 45 degrees relative to a bottom of the channel. 
     
     
         7 . The fish ladder of  claim 1 , further comprising at least one support leg adapted to attach to the ladder. 
     
     
         8 . The fish ladder of  claim 7 , wherein a length of the support leg is adjustable. 
     
     
         9 . A system for enabling fish migration comprising:
 a drainage structure; and   a fish ladder operably couplable to the drainage structure, the fish ladder comprising:
 a structure interface adapted to attach to the drainage structure, the structure interface portion including a weir plate; and 
 a ladder defining a channel for conveying water in a flow direction, the ladder including a plurality of baffles disposed across the channel generally transverse to the flow direction, the ladder operably coupled to the interface structure with a detachable hinged connection. 
   
     
     
         10 . The system of  claim 9 , wherein the detachable hinged connection comprises at least one hinge pin receiver on the structure interface, the at least one hinge pin receiver defining a first bore, a pin receiving sleeve on the ladder, the pin receiving sleeve defining a second bore, and a hinge pin received through the first bore and the second bore. 
     
     
         11 . The system of  claim 10 , wherein the ladder is shiftable about the hinge pin between a first position in which the ladder extends in a horizontal orientation from the structure interface and a second sloped orientation in which the ladder slopes downwardly from the structure interface. 
     
     
         12 . The system of  claim 9 , wherein the channel is defined by a pair of spaced apart substantially parallel side panels and a bottom panel extending between the side panels. 
     
     
         13 . The system of  claim 9 , wherein the baffles are angled rearwardly toward the structure interface. 
     
     
         14 . The system of  claim 13 , wherein the baffles are angled at about 45 degrees relative to a bottom of the channel. 
     
     
         15 . The system of  claim 9 , further comprising at least one support leg adapted to attach to the ladder. 
     
     
         16 . The system of  claim 15 , wherein a length of the support leg is adjustable. 
     
     
         17 . A fish ladder comprising:
 a structure interface adapted to attach to a drainage structure, the structure interface portion including a weir plate presenting a top flange and a locating structure extending upwardly from the top flange; and   a ladder including a pair of spaced apart side plates and a bottom plate defining a channel for conveying water in a flow direction, the ladder including a plurality of generally planar baffles extending between the side plates generally transverse to the flow direction, the baffles being disposed such that the plane of the baffles is angled relative to the bottom plate and a top edge of each baffle is disposed closer to the structure interface than a bottom edge of the baffle, the ladder operably coupled to the interface structure with a detachable hinged connection.   
     
     
         18 . The fish ladder of  claim 17 , wherein the baffles are angled at about 45 degrees relative to the bottom plate. 
     
     
         19 . The fish ladder of  claim 17 , wherein the detachable hinged connection comprises a pair of spaced apart hinge pin receivers on the structure interface, each hinge pin receiver defining a bore, a pin receiving sleeve on the ladder, the pin receiving sleeve defining a bore, and a hinge pin received through the bores of the hinge pin receivers and the bore of the pin receiving sleeve. 
     
     
         20 . The fish ladder of  claim 19 , wherein the ladder is shiftable about the hinge pin between a first position in which the ladder extends in a horizontal orientation from the structure interface and a second sloped orientation in which the ladder slopes downwardly from the structure interface.