Hamilton Kent Blog

The importance of micromonitoring for reducing I/I

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So your municipality has inflow and infiltration (I/I) problems, and you’re planning to rehabilitate your sanitary sewer pipelines or manholes to correct the problem.


As underground infrastructure suppliers, Hamilton Kent is happy to help you with this. But because we care about helping to solve your problems, we want to offer some advice before you invest a lot of money in replacing or rehabilitating your infrastructure.


It’s this: consider micromonitoring your sanitary sewer system flow.


Developed by Stantec Consulting Services, micromonitoring is a flow monitoring process that zeros in on specific areas where I/I is occurring. Once found, it eliminates the need and cost to continue monitoring (and rehabilitating) unnecessary touch points.


In some cases, micromonitoring has saved 80% of monitored sites from further testing and rehabilitation, using data collected after only a couple of rain events.


Interestingly, micromonitoring can identify whether the problem is an infiltration issue or an inflow issue, which helps in planning and budgeting repairs and rehabilitation methods more accurately.


What exactly are Micromonitors and how do they work? 


According to Stantec Micromonitor designer John Barton’s article in Public Works (2011):


Micromonitors are fabricated fiberglass weir inserts installed behind standard area-velocity probes. The weir insert has a defined rating curve. At very low levels the weir is used as a primary device. If flow exceeds the limit of the weir's rating curve, the continuity equation is used to calculate the flow from the level-velocity data. The addition of the weir conditions the flow over the probe to prevent obstruction by debris, enabling the Micromonitor to measure flows down to 1.0 gallons per minute (gpm) — generally in low-flow sewer segments like those with only a few houses. 


“The device is installed with a street-level insertion tool, eliminating issues related to Occupational Safety & Health Administration confined space entry (CSE) requirements. Thus the Micromonitors efficiently adapt existing equipment and open up a new approach for pinpointing inflow and infiltration in upstream segments. 


“Without the need for permitted installation, rapid deployment is the hallmark of the micromonitoring approach. One person can remove Micromonitors from at least eight sites, download the data, change the batteries, recalibrate the meter, and install Micromonitors in eight new sites in one workday.”


Read the whole article here:Low-impact inflow/infiltration investigation


For utilities and municipalities looking to get the most from their budgets and their data (while reducing inconvenience to property owners), we suggest looking into use of micromonitoring.


Once you have a good idea of what you need to replace and rehabilitate in your sanitary sewer systems, please do give Hamilton Kent a call.

Helpful articles on micromonitoring



Full disclosure: This article is not at all sponsored by Stantec. It is for informational purposes only.