Stormwater Open Curb Inlet Curb Throat Survey Measurements

Review Information Needed on Curb-Throat Measurements and Recording it on the Survey Form

All Fabco Industries Water Quality Inserts (WQIs) are manufactured to properly fit inlets by using specific information compiled in a survey of the “as-built” inlet. The Fabco Grate/Inlet Survey form serves as the tool to provide that information.

The “Opening” in Open Curb Inlets are called out as the “Curb Throat”. Providing accurate information about these curb throat dimensions is essential for an Open Curb Inlet Survey. While the dimensions are often the same size, some curb throats taper in one direction so the exterior opening may be larger or smaller than the interior opening. It is important to collect accurate measurements for both the interior and exterior openings of the curb throat.  Pictures of the interior and exterior curb throat opening are a useful and appreciated aspect of any Open Curb Inlet survey.

Recording Curb Throat Measurements

open curb inlet survey curb throat measurements boxes
open curb inlet survey curb throat measurements diagrams
open curb inlet survey curb throat measurements pictures

Does the curb throat have a grate or bars? If yes, is it removeable?

Some Open Curb Throats will have a grate or some bars in place at the front of the opening. Some of these grate or bars can easily be removed and put back in place in need be for installation purposes while some are permanently installed. Provided this information is critical to the design and installation of devices for some inlets. Example photos below.

Some Open Curb Throats will have a grate or some bars in place at the front of the opening. Some of these grate or bars can easily be removed and put back in place in need be for installation purposes while some are permanently installed. Provided this information is critical to the design and installation of devices for some inlets.
open curb inlet survey curb throat grate bars picture 2

Tandem Curb Throat Openings

Some Open Curb Inlets will have two curb throat openings in tandem, these inlets can take tandem Fabco devices as a solution. (L: Double Curb Throat Opening; C: First of two tandem StormSacks being placed into the Open Curb Inlet; R: Illustration of Tandem StormBasin design). 

open curb inlet survey tandem curb throat examples