Complying with California SB 88 - Los Angeles Post-ExaminerLos Angeles Post-Examiner

Complying with California SB 88

With the advent of SB 88, water users throughout California who “…divert, store, or use water from a surface source or divert water from a subsurface stream” are now required to report their water use to the California State Water Board, Division of Water Rights. This reporting is required annually and applies whether or not the water is from the user’s property or from another property.

Use of Flumes

For smaller water users, a flume may be an optimal solution for measuring their flow. Flumes are fixed, engineered structures that are place either in a channel or in line with piping.  By restricting the flow in specific ways, they develop a known relationship between the water level and the flow rate through the flume.

Relatively inexpensive, and general easy to install, flumes:

  • meet SB 88’s accuracy requirement of +/- 8 to 10%
  • have low maintenance costs, passing sediments, floating debris, and solids well
  • are easy to use/understand by even novice operators
  • have long useful lives
  • have low head loss
  • and are available in a wide selection of styles and sizes

Flume Types Commonly Used

Parshall Flume:

The Parshall Flume is a popular flume dating back from the 1920s.  The first of the true flumes used today, the Parshall was originally developed to help farmers and ranchers with their water rights and irrigation needs. The flume became so widely accepted that the Office of the State of Engineer in Colorado published a manual on the flume and how to use it.

Cutthroat Flume:

Over the years additional flume types were developed to address specific applications not well served by the Parshall.  One of these flumes, and one of the most recent, is the Cutthroat Flume.

The Cutthroat Flume follows the same general shape as the Parshall – having an hourglass shape when view from above – but unlike the Parshall, there is no extended throat and the floor of the flume is flat.  The flat floor makes it possible to install the Cutthroat flume on relatively flat gradients, while still allowing sediment to pass easily. The sharp contraction and immediate expansion of the throat means intermediate sizes of Cutthroat flumes can be developed – without the need for laboratory calibration!

For these reasons, more and more individuals and business impacted by SB 88 are using Cutthroat flumes to meet their flow monitoring needs.

Use of Secondary Meters

SB 88 has unique, tiered reporting requirements. As a water use increases, the amount of data required, and rapidity with which it must be reported, increases.  As this happens, it becomes laborious to go out into the field, measure the water level, and then record/report it.  To save time and automate the process, pressure transducers are commonly used to continuously measure the water level, and thus flow rate.  This helps streamline the monitoring/recording process.

Getting Started

While complying with SB 88 may seem daunting at first, it is usually just the initial recognition that something needs to be done that is the hardest.

Flow product and service providers can walk you through the monitoring needs and how to best select those devices that will help you measure, record, and report your water usage.

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