Integrated River Management - River Dynamics and Integrated River Management - page 724

Jiuzhai Creak is an example of such super-equilibrium. The average slope of Jiuzhai Creek is about 4%.
Hundreds of landslides created landslide dams and formed 118 lakes. The lakes are filled with water, and
are flat and smooth mirrors like surfaces. At the downstream end of the lakes the water flows over stones
and forms waterfalls or steep rapids with step-pool systems. The waterfalls are normally several to
several tens of meters high and the lakes are several meters to 80 m deep and have surface area of several
hundreds to nearly one million m 2 . The waterfalls and rapids are very stable and trees and shrubs have
grown on them, as shown in Fig. 11.8.

Fig. 11.7 Biomass per area of macroinvertebrates as a function of sediment deposition volume (Yu, 2008)

Fig. 11.8 Jiuzhai Creek in super-equilibrium

Another example of super-equilibrium is a mountain stream in the upper East River. As shown in Fig. 11.9,
many boulders on the stream bed create high resistance and protect the bed from erosion. The stream is
stable even during extreme flood events. Riparian vegetation develops very well. The biodiversity of benthic
invertebrates and fish are quite high. Some shrub and herbaceous species have colonized the stream bed.
Super-equilibrium involves high resistance and high biodiversity, and, therefore, is associated with good
river health.

11.1.3 Principles For River Management

Principle Ē — Extending the Duration of Water Flowing in Rivers
The river is the carrier of lives and provides aquatic creatures with various habitats. The floodplain and