Senate Bill 88 requires that all water right holders who have previously diverted or intend to divert more than 10 acre-feet per year or are authorized to divert more than 10 acre-feet per year under a permit, license, or registration, are required to measure and report the water they divert.
Diverters must measure their diversions monthly, weekly, daily, or hourly, depending on the type and size of diversion. In general, diverters only need to submit their measurement data to the State Water Board once per year. Data is submitted as an attachment to Annual Water Diversion and Use Reports. Optional datafile templates are available. Refer to the Measurement and Reporting Manual for more information on measurement frequency requirements.
Measuring devices can be any devices, including custom or in-house built devices, that directly measure either volume, flow rate, water velocity, or water elevation. Diverters must then use the measured value to calculate the volume of water diverted. Examples of measuring devices are shown in the table below.
Example Devices | Measured Parameter | Example Units | Formulas to Calculate Volume |
Totalizer; totalizing flow meter | Volume | Acre-feet; gallons; cubic feet | Not applicable |
Flow meter | Flow rate | Gallons per minute; cubic feet per second | Volume = flow rate x duration |
Velocity meter | Water velocity | Feet per second | Volume = velocity x cross sectional area x duration |
Staff gauge; transducer; weir | Water elevation | Feet | Diverter must provide formula |
Additional information regarding frequency of measurement, and how to report can be found on the State Water Resources Control Board website.