A groundwater control system and method for regulating the level of groundwater in an agricultural field according to selected criteria including a drainage tile line having a water flow regulator that is computer controlled through a communications link in response to the selected criteria to provide a water table profile for the field. Aspects include receiving an initial output of the linear sketch, generating a query vector and inputting the query vector into the linear sketch. A horn switch is disposed between the inner and outer covers for effecting operation of a horn.