Appendix B: Bioengineering for Streambank Erosion Control -- Guidelines
4 Monitoring and Aftercare
The Philosophy of Monitoring and Aftercare
Most agencies and private entities cannot afford extensive monitoring in an operational
setting in contrast to very definitive monitoring in a research and development setting. This
discussion focuses on the operational setting. Bioengineering projects continue to grow
stronger and stronger, once bed degradation is controlled, toe undercutting and scouring at
upper and lower ends of reach have been arrested, and plants become established. Deeply
penetrating plant roots hold the soil together and upper stems deflect current and wave energy
and slow local flow velocities. Then, sedimentation takes place and other pioneer plants start
to invade and further contribute to stability. The key, however, is to ensure that this early-on
establishment of plants takes place and this requires early monitoring and possible
remediation. Thus, early maintenance may be called for if this establishment is jeopardized.
In contrast, traditional projects such as riprapped revetment, may not require maintenance
early in the project life, but may need major maintenance at a much higher cost a few years
later. So, bioengineering may require early-on monitoring and remediation with the trade-off
being no maintenance or little maintenance in later years. Figure 43 (from Coppin and
Richards, 1990) illustrates this point.
Figure 43. Illustrations of different expenditure profiles and
maintenance (implied) of inert structures and bioengineering
treatments. (from Coppin and Richards, 1990)
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