Fiberglass Flumes

Fiberglass flumes are static pieces of equipment that are used to measure water flow in open channels. They are similar to weir boxes, however have the ability to measure higher flow rates, can pass debris more easily, are easier to install and maintain, and come in a variety of styles and sizes.

Which Flume is Right For Your Wastewater Management System?

One of the greatest benefits of flumes over weir boxes is that there are many to choose from. TRACOM provides the following flumes for wastewater management systems:

Parshall Flumes

Parshall flumes are the most widely used style of flumes for permanent installations. They are self-cleaning in most circumstances and not recommended for sanitary use in 1” and 2” sizes. The standard design of Parshall flumes conforms to U.S. Department of the Interior, Bureau of Reclamation, Water Measurement Manual.

Maximum Flow Rates:

  • Maximum flow rates from 85.3 GPM – 467,200 GPM with standard wall heights

Flume Sizes:

  • Available in throat widths of 1” to 180”

Available Options:

  • Available in nested configurations
  • Available with end adapters to connect to existing pipe

Submergence Information:

  • Resistant to the effects of submergence
  • 50% for 1″ – 3″ flumes
  • 60% for 6″ and 9″ flumes
  • 70% for 12″ – 96″ flumes
  • 80% for 120″ flumes

Flume Requirements:

  • Installation requires drop in conduit invert from inlet to outlet

Simple Flow Meter Calibration: Yes

Palmer-Bowlus Flumes

Palmer-Bowlus flumes are easily installed in manholes or round bottom channels. They have a smaller useful range of flows and often experience sedimentation at lower flow velocities. The proprietary design varies from manufacturer to manufacturer.

TRACOM offers Palmer-Bowlus flumes in three primary styles:

4D+1″ (permanent style with integral approach section)​

Point of measurement inside of the flume

2D+1″ (short sectioned flume with only the trapezoidal ramp)

Point of measurement upstream of the flume

Insert Style (2D+1″ length but no end flanges and O.D. of flume is I.D. of pipe)

Potential problems with accuracy due to reduced flume width

Maximum Flow Rates:

  • Maximum flow rates from 55.2 GPM – 198,535 GPM

Flume Sizes:

  • 4″-108″ sizes available (sized by throat width)

Available Options:

  • Available with bulkheads to connect to existing pipe
  • 4D+1″ – inlet and outlet
  • 2D+1″ – outlet only
  • Insert style – N/A

Flume Requirements:

  • Requires 25 straight run pipe diameters upstream
  • No invert drop required

Simple Flow Meter Calibration: No

HS / H / HL Flumes

H-Flumes are designed for a wide range of flows where discharge is unimpeded or spills freely from the flume. They were originally developed for agricultural runoff, but today are used in other applications as well. Each style has a flat bottom for self-cleaning of small debris. The standard H-Flume design conforms to U.S. Department of Agriculture, Field Manual for Research in Agricultural Hydrology.

Maximum Flow Rates:

  • Maximum flow rates from 36.0 GPM – 52,509.6 GPM

Flume Sizes:

  • Available in a wide range of sizes from 0.4’ HS – 4.0’ HL

Available Options:

  • Approach section and inlet bulkhead available for connection to existing pipe

Submergence Information:

  • Cannot operate under submerged conditions

Flume Requirements:

  • Require 3-5 times the maximum head in straight channel upstream of the flume

Simple Flow Meter Calibration: Yes

Trapezoidal Flumes

Trapezoidal flumes were initially designed to measure flows in irrigation channels, but today are used in many ways. They have an excellent usable head at low flow rates and their straight through bottom permits the passage of debris. Trapezoidal flumes conform to the normal shape of ditches (minimizing transition).

Maximum Flow Rates:

  • Maximum flow rates from 43.0 GPM – 663.8 GPM

Available Options:

  • End adapters are available for Small, Large, and Extra Large 60 Degree V Trapezoidal flumes to connect to existing pipe

Submergence Information:

  • Operates under higher degrees of submergence than Parshall flumes

Simple Flow Meter Calibration: No

Cutthroat Flumes

Cutthroat flumes are similar to Parshall flumes except they have a simpler construction with a flat bottom and no extended throat. The flat bottom is used for self-cleaning of small debris (1” and 2” throat widths are not recommended for sanitary flows). Cutthroat flumes are developed for use in flat gradient channels and their most common applications include stream gauging and flow splitting.

Maximum Flow Rates:

  • Maximum flow rates from 52.6 GPM – 43,494 GPM

Flume Sizes:

  • Sized by flume length and throat width

Available Options:

  • Not available with standard end adapters to connect to existing pipe

Submergence Information:

  • Operates satisfactorily under both free and submerged flow conditions

Simple Flow Meter Calibration: Yes

RBC Flumes

RBC flumes have a simple construction and are basically scaled versions of a general flume. They are developed for use in small furrows and unlined canals ideal for very low flow rates. In addition RBC flumes are portable and should not be used in flows with high solids content.

Maximum Flow Rates:

  • Maximum flow rates from 22.98 GPM – 790.79 GPM

Flume Sizes:

  • Five throat widths (50mm, 75mm, 100mm, 150mm, 200mm)

Flume Requirements:

  • Inlet and outlet wingwalls recommended for use in unlined canals

Simple Flow Meter Calibration: No

Montana Flumes

Montana flumes come with a design similar to a Parshall flume with the throat and discharge sections removed. They are not commonly used in the wastewater management industry. In most circumstances, Montana flumes are self-cleaning (not recommended for sanitary use in 1” and 2” sizes). They use the same discharge table as a similarly sized Parshall flume and the standard design conforms to U.S. Department of the Interior, Bureau of Reclamation, Water Measurement Manual.

Maximum Flow Rates:

  • Maximum flow rates from 85.3 GPM – 467,200 GPM

Flume Sizes:

  • Available in throat widths of 1” to 144”

Available Options:

  • Available in nested configurations
  • Available with inlet end adapter to connect to existing pipe

Submergence Information:

  • Cannot withstand any degree of submergence

Simple Flow Meter Calibration: Yes

Each fiberglass flume style has its own advantages, disadvantages, and flume liner. TRACOM recommends considering the characteristics of each flume before your company makes a decision. To learn more information or speak to a specialist about which fiberglass flume best meets your needs, call 877-435-8637