Erosion Control with Manhole Risers

Manhole Risers: Inflow & Infiltration (I&I)

Inflow & Infiltration (I&I) happens when ground and storm water seep into a sanitary sewer system through defects within a collection system. Cross connected public infrastructure, downspouts, sump pumps, driveway drains, stairwells, and streams can all contribute to I&I.

Effective erosion control measures are crucial to managing I & I, to help reduce water pollution and protect property. Since manholes can contribute significant inflow and infiltration, it’s important to inspect them to identify any signs of leaks or erosion.

Sources of Inflow & Infiltration

I&I can result from the use of poor construction materials and outdated methods. It’s an unfortunate fact that some contractors raise manholes using bricks or concrete grade rings to build the riser.  These methods require grouting at all mating joints and then sealing the interior with a sealant, usually of cement.  This kind of riser structure does not allow for the installation to be height / slope accurate and is subject to rapid deterioration.

When it comes to preventing I&I, it is important to inspect the following sources and causes of manhole leaks and deterioration. These include:

• Cover and seal
• Under frame/casting
• Joints, cracks, and holes
• Pipe seals
• Hydrogen sulfide corrosion
• Ground water level
• Traffic loading/impact
• Freeze/thaw cycle

Elimination of I&I Concerns

By eliminating mating joints and use of grout, the WhirlyGig Manhole Riser is the most effective solution to stopping I&I in wastewater systems. Easy to install, our high-quality, pre-formed thermoplastic forms are constructed to outlast other manhole risers and has the added benefit of being more cost effective and of higher quality  With our manhole riser solution I&I is a thing of the past and you can look forward to at least 25 years of maintenance-free service.

WhirlyGig Manhole Risers

At WhirlyGig, we provide a manhole riser solution that inherent to its design results in a much easier, more cost effective, higher quality and safer installation compared to traditional methods such as concrete grade rings.  With the Whirlygig Manhole Riser solution you “Set it an forget it!” and can expect at least 25 years of maintenance-free service

Want to learn more? Contact WhirlyGig by filling out our online form or call us at 1.800.307.4263. We would love to hear from you and look forward to helping you recognize the value of the WhirlyGig system as the premier manhole riser solution.