This crude form of flow control is obviously impractical today due to it's requirement of flood land. With the advent of electricity producing turbines, flow control was now required to exactly match the power generated to to the power being consumed. The precise flow regulator oftne cost more than the turbine it was controlling flow for. Neither of these problems exist for owners of small domestic water power plants today. There are many ways to replace the old mill pond.
Batteries can store unused energy.
A gemini synchronous inverter can interface the utility company's power lines, using their lines as a battery or an energy reservoir. A load diversion govenor can divert the power output from a promary to a scondary load. An alternator govenor regulates the power output to match the load. And improvements have been made to the physical water control, with the availability of simple mechanical waterflow diverter govenors. The intial step in establishing a water power system is to measure the available power.