What's old is new again. The restrictor device described here is more or less the same as the "miner's inch" that defines water rights in parts of California. At least in Nevada County, some tracts of land include rights to "miner's inches" of water. A miner's inch was customarily the amount of water that'd flow through a inch diameter hole in a wooden board that was used as a sort of valve at the irrigation ditch. It's defined here nowas 11.22 gallons per minute (the amount varies by jurisdiction). It doesn't sound like a lot but sure adds up quick if you're filling a reservoir or storage tank.

Historically the water was used by miners to wash gold out of ore (or later, to hydraulically blast apart hillsides).