Evaluating cellular confinement systems as an alternative to control post-construction stormwater channel erosion

In the Southern US, particularly in regions near the Gulf of Mexico coast, availability of riprap to prevent channel erosion is limited. As a result, transportation costs for this type of lining can be very high, rendering this type of erosion protection alternative costly. The underlying idea of riprap is to mitigate strong shear forces and resuspension on soil particles at the bottom of channels. A similar outcome can be achieved with empty cellular confinement systems (CCS), also known as geocells. With appropriate cell geometry, the development of two counter-rotating flow patterns per cell is noticed, which have reduced particle resuspension and shear stresses. Interestingly, when inadequate cell geometries were considered (i.e., height to width ratios of 2), erosion was worse than the scenarios with no CCS protection. Further research involves using CCS in an actual stormwater channel near a roadway, and the deployment was successful in that no signs of erosion or deleterious changes in water quality parameters were detected. While more tests are still needed, it indicates the potential use of CCS to replace riprap as in the context of post-construction stormwater management as an alternative to control erosion.

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