trash screen 25 in a raised position on second gate 14 debris will drop off into tailwater 12 fig1 illustrates an enhanced approach to removing debris from trash screen 25 fig1 shows a detail of trash screen 25 with a set of nozzles 51 installed fed by a pump 53 driven by a motor 53 m with air or water via a piping system 52 installed behind trash screen 25 nozzles 51 direct water to flow in upward direction 54 carrying debris otherwise stuck on trash screen 25 over the top of second gate 14 this system works also in the raised position of second gate 14 ejecting debris from trash screen 25 into tailwater 12 fig1 and 12 illustrate another alternative embodiment 120 but one that is not mechanically connected to piers 2 3 4 etc rather embodiment 120 is placed adjacent to and downstream of piers 2 and 3 of an existing dam and uses first gate 32 of the dam to provide shut off for second gate 64 second gate 64 and other apparatus 17 21 22 23 25 26 28 29 and 31 as shown are supported by two or more pylons 56 bored into the bedrock 7 downstream of and in line with piers 2 3 4 etc and such support is independent of piers 2 3 4 etc drilling into bedrock 7 to place pylons 56 is done from a barge not shown and does not require a cofferdam pylons 56 support a structure that.