Integrated River Management - River Dynamics and Integrated River Management - page 720

In China, the Guanting Reservoir was built on the Yongding River in 1953 with main purposes of
flood control and water supply to Beijing. At the time of construction about 2 billion m 3 of fresh water
flowed into the reservoir annually. Since 1953 numerous dams have been constructed in the upper Yongding
basin. All the river water is used before it flows into the Guanting Reservoir. Now, the Guanting
Reservoir receives only 0.2 billion m 3 of sewage water discharged from upstream cities and towns. The
ecology of the river has been impacted so seriously that there are almost no fish living in the river and
the taxa richness of benthic invertebrates has been reduced from several tens of species to only a few
species. Figure 11.2 shows the polluted water at the confluence of the Sanggan River and the Yanghe
River, which is located at the upper end of the Guanting Reservoir. The figure also shows the two species
of macro-invertebrates of Oligochaeta and Chironomidae found in the river bed. Both species are very
tolerant and may live in heavily polluted water.
The three case studies show that integrated river management is needed. The river uses must be
integrated with the management of hydrology, the ecological system, land use, and the fluvial processes.
An integrated river management index, I, is introduced:

(11.2)
in which H is a hydrology management index; S is a sediment management index; G is a fluvial process
and landscape management index; E is an ecological system management index; L is a land use management
index; R is a river use index; and w i is weight value for the i -th index.

I wR wH wS wG wE wL

0 1 2 3 4 5

Fig. 11.2 Polluted water of the confluence of the Sanggan River and the Yanghe River at the upper end of the Guanting
Reservoir and two tolerant species of macro-invertebrates of Oligochaeta and Chironomidae (See color figure at the
end of this topic)

The index R is the sum of the economic benefit from power generation, navigation, water supply,
tourism and recreation; H can be calculated as the relative change to the hydrological cycle; S is the
intensity of complex influence on the sediment budget; G is the induced instability of the river channe
and change of landscape; E can be measured as the reduction in number of species of floral and faunal
communities; and L is the value of land use change. The weight values w i must be determined from case
studies. The assessment of integrated river management level of river management projects can be
valued with the index I . The higher is the value of I , the better the river management system.

11.1.2 Stability of Rivers
The stability of rivers is the most important factor for river health. Mountain rivers and alluvial rivers are