1. (a) Measurement Methodology Content. For each measurement methodology used to measure and account for the required measurement parameters described in section 933, each diverter must electronically submit a measurement methodology on a form available through the online reporting platform and containing the following information, as applicable:

   1. (1) Name and contact information, including email address, for:

      1. (A) All participants covered by the measurement methodology;
      2. (B) The primary contact person to represent all diverters covered by the measurement methodology in measurement matters; and
      3. (C) The qualified individual who certified that the measurement methodology meets the requirements of this chapter;
   2. (2) Identification number of each claimed water right covered by the measurement methodology;
   3. (3) Identification of each point of diversion covered by the measurement methodology and of each measurement location and measuring device included in the measurement methodology;
   4. (4) An explanation of any quality assurance protocol used to ensure the quality and accuracy of the measurement data;

   5. (5) For any measuring device that does not directly measure both discrete volume and rate, the conversion method or formula used to convert the measurement data to volume and rate, including the following:

      1. (A) For a measuring device that measures flow rate only, the conversion method must describe the protocol used to record the duration of operation during each measurement interval, where volume may be derived by the following formula: volume = (flow rate) x (duration);
      2. (B) For a measuring device that measures cumulative volume only, the conversion method to derive the discrete volume diverted within the measurement interval may use the following formula: discrete volume = (cumulative volume at the end of the interval) -- (cumulative volume at the beginning of the interval). The conversion method to derive the flow rate must describe the protocol used to determine the duration of operation during each measurement interval, where flow rate may be derived by the following formula: flow rate = (volume diverted in each measurement interval) / (duration);
      3. (C) For a measuring device that measures water velocity only, the conversion method must describe the protocol used to determine the cross-sectional area of flow and the duration of operation during the measurement interval, where volume and flow rate may be derived by the following formulas: volume = (velocity) x (cross-sectional flow area) x (duration), and flow rate = (velocity) x (cross-sectional flow area); and
      4. (D) For a measuring device that measures water elevation at the point of measurement, electricity consumption, electricity generation, or any other parameter, the conversion method must describe the methodology or formula used to determine the volume and flow rate of water diverted;
   6. (6) A description of the methodology used to aggregate hourly or more frequent measurement data to reflect daily values;
   7. (7) A description of the methodology used to distinguish measurement data for water directly diverted, diverted to or collected to storage, withdrawn or released from a qualifying reservoir, or rediverted, as applicable and if not measured individually;

   8. (8) For the general measurement datafiles described in subdivision (a) of section 935, a description of the methodology used to distinguish and apportion general measurement data to each claimed water right covered by the measurement methodology. The aggregate general measurement data must meet the accuracy requirements of subdivision (i) of section 933, but any individual apportionment may be a reasonable approximation as follows:

      1. (A) For a group of diverters covered by the same measurement methodology, the methodology for apportioning general measurement data to each claimed water right may include calculations based on the reasonably approximated percentage of water diverted under each claimed water right;
      2. (B) For a diverter with multiple claimed water rights covered by the same measurement methodology, the methodology for apportioning general measurement data to each claimed water right may include calculations to allocate diversion amounts to each claimed water right; and
      3. (C) For a diversion that the diverter attributes to multiple claimed water rights and/or a combination of contract deliveries and claimed water rights, the methodology must identify these and apportion general measurement data between them;
   9. (9) Any other description of the measurement methodology and how it is implemented to derive the measurement data submitted under section 935 from the raw device output; and
   10. (10) A certification by a qualified individual that the measurement methodology meets the requirements of this chapter.

2. (b) Registering Measuring Devices. Diverters must register each measuring device included in the measurement methodology as follows:

   1. (1) For each active measuring device used before October 1, 2026, diverters must register the measuring device with the board in accordance with this subdivision on or before January 31, 2027. For each measuring device used on or after October 1, 2026, diverters must register the measuring device with the board in accordance with this subdivision on or before the submission deadline of the annual report for which the measuring device is first used. Diverters must also register each measuring device with the board in accordance with this subdivision within 30 days of a request by the deputy director.
   2. (2) For any changes to the location of a measuring device, diverters must update the measuring device registry on or before the submission deadline of the annual report for which the changes first apply. Diverters must also update the measuring device registry within 30 days of a request by the deputy director.

   3. (3) Diverters must register each measuring device included in the measurement methodology by electronically submitting the following information, as applicable, on a form available through the online reporting platform:

      1. (A) Identification number of each claimed water right that uses the measuring device or recording device;
      2. (B) Make and model number of the measuring device;
      3. (C) Type of measuring device, such as inline flow meters, submerged orifice gates, rectangular weirs, v-notch weirs, broad crested weirs, or other class of device designed to perform a similar function;
      4. (D) Location of the measuring device, including identification of any associated point of diversion;
      5. (E) Make, model number, and type of the recording device, if different from the measuring device;
      6. (F) Measured parameter and associated units of the raw device output;
      7. (G) Accuracy of the measurement data;
      8. (H) Date of installation; and
      9. (I) Contact information for the qualified individual who installed and verified the accuracy of the measuring device.

3. (c) Measurement Methodology Submission and Implementation. Each measurement methodology must be submitted to the board and implemented as follows:

   1. (1) Diverters who have used a measuring device before October 1, 2026 must submit a measurement methodology to the board in accordance with this section on or before January 31, 2027. For new measurement methodologies used on or after October 1, 2026, diverters must submit a measurement methodology to the board in accordance with this section on or before the submission deadline of the annual report for which the measurement methodology first applies.
   2. (2) For any changes or modifications to a previously submitted measurement methodology, diverters must submit a revised measurement methodology to the board on or before the submission deadline of the annual report for which the changes first apply.
   3. (3) Measurement methodologies submitted in accordance with this section will be considered accepted by the board and must be timely implemented. The division may review any submitted measurement methodology in accordance with subdivision (e).
   4. (4) Measurement methodologies will be presumed to remain in effect until cancelled, updated, or otherwise modified by the diverter, or rejected by the division.
   5. (5) Measuring devices may only be installed and calibrated by a qualified individual who meets the requirements of subdivision (p) of section 931.
   6. (6) All measuring devices and measurement infrastructure installed after February 1, 2026 must be installed in a manner and location that does not result in a serious or major disturbance to an environmental or public trust resource and avoids exception criteria listed in title 14, section 15300.2 of the California Code of Regulations.

4. (d) Evidence of Proper Functioning. Diverters must submit evidence to the board's online reporting platform verifying that each measuring device included in the measurement methodology is functioning properly and that the non-provisional measurement data meet the accuracy requirements described in subdivision (i) of section 933 as follows:

   1. (1) Such evidence may include, but is not limited to, calibration reports, laboratory certification documentation, field-test reports, or an affidavit or declaration of a qualified individual documenting the accuracy and proper functioning of the measurement methodology and associated measuring devices;
   2. (2) Evidence of proper functioning must be submitted on or before the submission deadline of the first annual report after the measuring device was installed and at least once every five years thereafter. Evidence of proper functioning must also be submitted upon request by the deputy director; and
   3. (3) A qualified individual must certify that all evidence of proper functioning submitted in accordance with this section is accurate to the best of their knowledge.

5. (e) Review and Verification. The division may:

   1. (1) Review any measurement methodology and request additional information to support a measurement methodology;
   2. (2) Audit a measurement methodology, conduct a field inspection, or request additional information from the diverter to determine if all measuring devices have been properly installed and if the measurement methodology has been properly implemented to meet the requirements of this chapter. The diverter must make all measuring devices reasonably available and accessible for inspection upon request;
   3. (3) Confer informally with the sponsor or participants of a measurement methodology to suggest modifications to the measurement methodology;
   4. (4) Require changes or modifications to a measurement methodology to meet the requirements of this chapter or to correct a deficiency. Such changes or modifications must be made and implemented within a reasonable time;
   5. (5) For a measurement methodology that does not include installation of a measuring device at each point of diversion, require the diverter to install a measuring device at each point of diversion within 90 days if identified deficiencies in the measurement methodology are not timely corrected, or if the measurement methodology is rejected;
   6. (6) Approve, with or without conditions, any measurement methodology that meets the requirements of this chapter; or
   7. (7) Reject any measurement methodology that fails to meet the requirements of this chapter. The division must notify the diverter in writing if the measurement methodology has been rejected, and written notices of rejection must include the basis for the rejection. The rejection of a measurement methodology shall not retroactively affect the compliance status of a submitted and implemented measurement methodology.
6. (f) An incomplete measurement methodology or documentation for a measurement methodology that does not meet the minimum standards of this section shall not relieve the diverter of fully meeting the requirements of this chapter.

Note: Authority cited: Sections 1058 and 1841, Water Code. Reference: Sections 13, 183, 1051, 1840, 1841.5, 1846 and 5103, Water Code.

History

1. New section filed 3-21-2016 as an emergency; operative 3-21-2016 (Register 2016, No. 13). Pursuant to Water Code section 1841(b), the regulation shall remain in effect until revised by the State Water Resources Control Board.

2. Renumbering of former section 934 to 939.5 and new section filed 1-21-2026; operative 2-1-2026 pursuant to Government Code section 11343.4(b)(3) (Register 2026, No. 4).