California Code of Regulations
Title 23 - Waters
Division 3 - State Water Resources Control Board and Regional Water Quality Control Boards
Chapter 2.8 - Measuring and Monitoring
Section 933 - Measuring Device Requirements

Universal Citation: 23 CA Code of Regs 933

Current through Register 2024 Notice Reg. No. 38, September 20, 2024

(a) Measurement Options. A diverter may choose any measuring device, or combination of devices, that meet the requirements of this section.

(b) Data.

(1) Data Recording. The measuring device shall be capable of recording the date, time, and at least one of the following: total volume of water diverted, flow rate, water velocity, or water elevation. The data shall be recorded in a format retrievable and viewable using Microsoft Excel, Microsoft Access, or other software program authorized by the deputy director. The measuring device shall be capable of recording the required information as follows:
(A) For direct diversion:
(i) On an hourly or more frequent basis for a diverter with a right or a claimed right to divert 1000 acre-feet of water per year or more.

(ii) On a daily or more frequent basis for a diverter with a right or a claimed right to divert 100 acre-feet of water per year or more.

(iii) On a weekly or more frequent basis for a diverter with a right or a claimed right to divert more than 10 acre-feet of water per year.

(B) For direct diversion by a diverter with multiple claimed rights:
(i) On an hourly or more frequent basis, where the sum of the diversions made under the claimed rights from the same point of diversion or to serve the same place of use is 1000 acre-feet of water per year or more.

(ii) On a daily or more frequent basis, where the sum of the diversions made under the claimed rights from the same point of diversion or to serve the same place of use is 100 acre-feet of water per year or more.

(iii) On a weekly or more frequent basis, where the sum of the diversions made under the claimed rights from the same point of diversion or to serve the same place of use is greater than 10 acre-feet of water per year.

(iv) In the event of any conflict between recording requirements for a diverter with multiple claimed rights from the same point of diversion or to serve the same place of use, the more stringent requirement shall control.

(C) For storage in a reservoir or pond:
(i) On an hourly or more frequent basis for a reservoir or pond with a storage capacity of 1000 acre-feet or more.

(ii) On a daily or more frequent basis for a reservoir or pond with a storage capacity of 200 acre-feet or more.

(iii) On a weekly or more frequent basis for a reservoir or pond with a storage capacity of 50 acre-feet or more and less than 200 acre-feet.

(iv) On a monthly or more frequent basis for a reservoir or pond with a storage capacity of greater than 10 acre-feet and less than 50 acre-feet.

(v) In the event of any conflict between recording requirements for a diverter with multiple claimed rights to divert to storage in a reservoir or pond, the more stringent requirement shall control.

(2) Data Submittal.
(A) Each diverter to which a measurement requirement applies shall submit the data from each measuring device to the board as required by chapter 2.7 of division 3 of this title, and within 30 days of any request or order by the board.

(B) For a reservoir subject to drawdown and refill during the collection to storage season, or that is otherwise operated in a cyclical manner, the maximum and minimum water surface elevations, the corresponding reservoir volume, and the monitoring dates shall be measured and the resulting data maintained.

(C) For each reservoir, if water is diverted or flows into the reservoir under more than one bases of right, including groundwater or water purchased under a contract, the amounts reported to the board shall be limited to the amounts covered by the water right being reported. A record of the alternative supplies entering the reservoir throughout the year shall be maintained to demonstrate that water stored is under a separate basis of right or contract.

(3) Data Retention. Each diverter shall keep records of the data from each measuring device for a period of no less than 10 years.

(4) Telemetry Requirements.
(A) This paragraph applies to any diverter who:
(i) Diverts more than 10,000 acre-feet annually; or

(ii) Owns or operates a reservoir or pond with a storage capacity of 10,000 acre-feet or more; or

(iii) Diverts during the period from June 1 through September 30, and directly diverts more than 30 cubic feet per second at any time; or

(iv) Diverts during the period from June 1 through September 30, and has claimed water right(s) to more than 20 percent of historic calculated mean monthly stream flow as measured by a stream gage with publically available records maintained by the U.S. Geological Survey, the California Department of Water Resources, the U.S. Army Corps of Engineers, or the board, or such other percentage as the deputy director or board shall determine; and any of the following conditions apply:
(a) Threatened, endangered, or fully protected fish species are present or have historically been present; or

(b) The diversion is made from a stream that is part of the board's North Coast Instream Flow Policy area; or

(c) The diversion is made from the Deer Creek, Mill Creek, or Antelope Creek watersheds of the Sacramento River watershed; or

(d) The diversion is made from the Mark West Creek, Green Valley Creek, Mill Creek, or Dutch Bill Creek watersheds of the Russian River watershed.

(B) This paragraph applies to all rights, claimed rights, or combinations of rights and claimed rights to divert from a single or shared point of diversion if the sum of such rights or claimed rights meets the criteria of subparagraphs (A)(i), (A)(iii), and (A)(iv) of this paragraph.

(C) By January 1, 2020, diverters subject to subparagraphs (A)(i), (A)(ii), or (A)(iii) of this paragraph shall provide telemetered diversion data via a public website that displays the data on at least a daily basis, and that is updated weekly, at minimum. For diverters subject to subparagraph (A)(iv), the deputy director may establish the appropriate date and percentage of stream flow for telemetering after notice and opportunity for comment. The data shall be provided to the board upon the request of the deputy director in a format retrievable and viewable using Microsoft Excel, Microsoft Access, or other software program authorized by the deputy director. The deputy director shall not require any diverter who diverts less than 10 percent of the historic calculated mean monthly stream flow to provide telemetered diversion data.

(D) The board may adjust the percent threshold of historic calculated mean monthly stream flow below 10 percent on an individual stream after notice and opportunity for comment and following a board meeting.

(c) Calculating Volume from Recorded Data. If a measuring device measures the flow rate, water velocity, or water elevation, and does not report the total volume of water diverted or delivered, the diverter shall report the conversion method used to convert the measured value to volume. The conversion method shall be approved by a qualified individual.

(1) For a measuring device that measures flow-rate, the report shall describe protocols used to record the duration of operation where volume is derived by the following formula: Volume = (flow rate) x (duration).

(2) For a measuring device that measures flow velocity only, the report shall describe protocols used to determine the cross-sectional area of flow and the duration of operation, where volume is derived by the following formula: Volume = (velocity) x (cross-section flow area) x (duration).

(3) For a measuring device that measures water elevation at the device (e.g. flow over a weir or differential elevation on either side of a device), the report shall describe protocols used to derive flow rate at the measuring device and the method or formula used to derive volume from the measured elevation value(s).

(d) Required Accuracy. The accuracy for each measuring device applies to the volume diverted or stored.

(1) A measuring device installed on or before January 1, 2016, shall be certified to be accurate to within +15 percent by volume based on periodic testing of the installed device.

(2) A measuring device installed or replaced after January 1, 2016 that is used to measure the diversion of water shall be certified to be accurate to within:
(A) ±5 percent by volume in the laboratory if using a laboratory certification.

(B) ±10 percent by volume based on periodic testing of the installed device if using a non-laboratory certification for a diverter with a right or a claimed right greater than or equal to 100 acre-feet per year.

(C) ±15 percent by volume based on periodic testing of the installed device if using a non-laboratory certification for a diverter with a right or a claimed right greater than or equal to 10 acre-feet per year.

(3) A measuring device installed or replaced after January 1, 2016 that is used to measure the water stored in a reservoir or pond shall be certified to be accurate to within:
(A) ±10 percent by volume in based on periodic testing of the installed device for a reservoir or pond with a storage capacity of 200 acre-feet or more.

(B) ±15 percent by volume in based on periodic testing of the installed device for a reservoir or pond with a storage capacity greater than 10 acre-feet and less than 200 acre-feet.

(e) Certification of Accuracy. The accuracy of a measuring device shall be initially certified and documented as follows:

(1) For a measuring device installed prior to January 1, 2016, the accuracy required shall be initially certified and documented by field-testing performed by an individual trained in the use of relevant field-testing equipment. The results from the field testing shall be documented in a report approved by a qualified individual and shall be filed with the next subsequent water use report. Stream gages installed and maintained by the U.S. Geological Survey or the U.S. Army Corps of Engineers do not require additional certification of the stream gage device accuracy pursuant to this section.

(2) For a measuring device installed or replaced after January 1, 2016, the accuracy shall be initially certified and documented by either:
(A) Laboratory certification prior to installation of a measuring device as documented by the manufacturer or an entity, institution or individual that tested the device following relevant industry-established protocols. Documentation shall include the manufacturer's literature or the results of laboratory testing of an individual measuring device or type of measuring device; or

(B) Non-laboratory certification after the installation of a measuring device based on periodic testing of the installed device, as documented by either:
(i) The affidavit or declaration of a qualified individual documenting the design and installation of the measuring device at a specified location; or

(ii) A report approved by a qualified individual documenting the field-testing performed on the installed measuring device by an individual trained in the use of field testing equipment.

(f) Protocols for Field-Testing and Field-Inspection and Analysis. Field-testing shall be performed for a measuring device according to the manufacturer's recommendations or design specifications and be overseen by a qualified individual. Field inspection and analysis protocols shall be performed and the results shall be approved by a qualified individual for each measuring device to demonstrate the following:

(1) The design and installation standards used for each measuring device meets the accuracy standards of subdivision (d) of this section; and

(2) The operation and maintenance protocols will ensure compliance with the accuracy standards of subdivision (d) of this section.

(g) Installation, Maintenance and Performance Requirements. A measuring device shall be installed, maintained, operated, inspected, and monitored to ensure the accuracy standards of subdivision (d) of this section are met. The installation of a measuring device shall be performed by a qualified individual.

(h) Calibration. The measuring device shall be calibrated by a qualified individual upon installation and at least once every five years thereafter. The diverter shall be responsible for more frequent calibration of measuring device(s) as necessary to ensure the accuracy requirements of subdivision (d) of this section are met.

(i) Measuring Device Location. No delivery or use of water shall occur between the point of diversion and the location of the measuring device, unless otherwise measured.

(j) Accessibility. The measuring device shall be installed in a manner such that it is readily accessible for reading, inspection, testing, repair or replacement. The diverter shall make the measurement device reasonably available for inspection by an authorized representative of the board upon request. The diverter shall provide the board's representative with reasonable access to inspect the measuring device. Failure to provide such reasonable access is a violation of this regulation.

(k) Verification of Measuring Device. The board may conduct a field inspection or request additional information from the diverter to determine if the measuring device has been properly installed and meets the requirements of this section. Failure to timely install a measuring device or verify its accuracy is a violation of this regulation.

(l) Inadequate Measuring Device. If a measuring device fails to meet the accuracy requirements of subdivision (d) of this section, the diverter shall repair or replace the measuring device at their own expense to meet such requirements.

(1) Notification. A diverter shall timely notify the board in writing upon detecting that the holder's measuring device does not comply with the accuracy requirements of subdivision (d) of this section. The notification shall include the diverter's plan to take appropriate, timely corrective action to comply with the accuracy requirements of subdivision (d) of this section.

(2) Enforcement. Failure to timely repair or replace a measuring device that does not comply with the accuracy requirements of subdivision (d) of this section is a violation of this regulation.

(m) Lawful authority. Nothing in this section shall be construed to limit or modify the board's authority to obtain information under any other lawful authority.

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.

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

Disclaimer: These regulations may not be the most recent version. California may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.