16. A siphon tube level control system for a reservoir having a fluctuating water supply such as an irrigation ditch
comprising a plurality of siphon tubes arranged along the bank
of the reservoir, selected ones of said tubes having an inlet
extending into the water in the reservoir and an outlet
extending outside the reservoir and leading to a runoff area
along said irrigation ditch to draw the water from the reservoir
in a siphon action, float-controlled valve means associated
with said ones of said siphon tubes including a valve member
at the outlet of each of said ones of said tubes responsive to
the water level in the reservoir to stop the flow through said ones of said siphon tubes when the water level in the reservoir
drops to a preselected lower level and to automatically open
the valve members and restart the siphon action in said ones of
said tubes each time the water level rises to a preselected
higher level to maintain the water in the reservoir between
said upper and lower levels.