Since You may have flood conditions, then the dam can not be made flat vertical, it has to be sloped up the stream, at about 45 degrees (lower better) to insure that the fast water "slides" and do not present a heavy pressure to the dam.
Then You are going to place a WEIR to the side that has a lower setting to allow the water to go out faster, and if possible do place heavy rocks directing the water toward the WEIR, the bottom cut of the WEIR should be at least 10 to 12 inches above the pipe intake.
The debris filter holes should be at least 1/3 size of the Nozzle area if you are using Turgo or Pelton.
Also the debris "shield" needs to be at least 2 pipe diameter away from the intake pipe, with the "holes" area not less than 10 times the pipe diameter times the cubic root of the pipe water velocity to minimize the "clogging" of the screen filter holes, so You need to see that screen should be large for best hydro operation.
Power GO for the extra length, you get 50 % more power by just going farther with the pipe run.
Go for a high voltage generator, like 120 or 220 volts for easy power transmission then use transformers to bring the voltage to the battery bank needs, also if done properly the Vac can be used directly in the house
Seal the large rocks lower area with concrete, MOST of the people that I helped in USA and CANADA do not listen the suggestions for the DAM and always end up complaining about the dam or going to do a reconstruction of the dam to get best results.
The most important part of a hydro is the INTAKE section, do pay good time optimizing it, to obtain best water harvesting to produce maximum power.
What type of Turbine are You planning to use ?.
For 36 feet head = 10.9 meter head with 3.78 liter/sec = 1 gallon/sec = 60 GPM,You can obtain 248 watts, or 5.95 KWH/day
That is 50 % higher if going 24 feet head
Nando