The drip irrigation system must be monitored and operated.  It cannot be stressed enough how important the first two categories (flow meters and pressure gauges) are to assess performance and guidance for operation, and how important the last two categories (valves and controllers) are to deriving the maximum benefit from a drip irrigation system. System Flow Meters System Flow Meters are available in a range of sizes and types, and commonly provide both instantaneous and cumulative water flow with an accuracy of approximately two percent.  Flow meters may also be fitted with electrical analog conversion units that are capable of transmitting flow rate data to a centralized irrigation control computer.  A micro-irrigation system offers the user an unprecedented degree of control over his water and power costs, and over the growing conditions of his crop.  To take full advantage of this ability to control the irrigation system, it is necessary to