**3. Successful cases by applying SPP strategy (too turbid)**

The idea of SPP for lake and reservoir water management is new, but this does not mean that the similar strategy has never been applied by far. In this section, we will discuss two cases to show that if SPP is not applied, the water related problems cannot be solved, while if the strategy is applied, all problems become solvable.

In 1854 Dr John Snow demonstrated the connection between water supply and Cholera as shown in Fig. 4. Several years later, Thomas Hawksley in Nottingham suggested that water supply systems should be piped to prevent external pollution.

Here the suggestion of pipe transport implied the idea of "separation, prevention and protection". Like the enclosed levee shown in Fig. 3, the pipe can *separate* clean water from the polluted water, and only clean water is allowed to enter the pipe network; likewise, the pipe protects the clean water inside the system and prevents the external pollutions. Consequently, the problem of waterborne illness death rate like Cholera, typhoid fever and dysentery had rapidly dropped to a very low level as shown in Fig. 5. This is probably the first time in history using the strategy of SPP for water resources management, and the concept of pipe water has been widely accepted in the world since then.

However, for large water system, so far there is no direct example of SPP strategy in application. Sometimes, people were forced to adapt the strategy of SPP to solve their problems. One of the examples is the Sanmenxia Reservoir in the middle reach of Yellow River, China. Yellow River basin is one of the largest basins in the world, and it is notorious in the world for high sediment transport rate in the middle reach. Between 1919 and 1960, the measured data at Sanmenxia Station showed that the mean annual runoff was 42.3×109 m3 and the long-term average annual sediment load was 1.57×109 t with the average concentration of the river water being 49.8 kg/m3, the highest in the world.

Sanmenxia Reservoir is created by the Sanmenxia dam. It is a large-scale multipurpose project, and the first one constructed on the main stream of the Yellow River. The construction of the dam was started in 1957, and the impoundment of water commenced in September 1960. The dam height is 106m at the pool level 323m with the storage capacity of 3.6×109 m3.

gravity via its outlets, and the water level quickly drops after flood period. If the proposed scheme is applied, the clean water will be protected, and sufficient high quality freshwater during flood period will be kept in the lake through the drought period until the next rainy season just like a reservoir. In other words, the water level is still high even after flood period. This water can be used by the human society to sustain their developments. Most importantly, during dry periods, all sluice gates are closed, the inner levee protects the lake water against external pollution, and it also prevents unnecessary

The core idea of SPP is that the water should be separated based on its quality or turbidity; the unwanted water should be prevented mixing with the clean water, and good quality water must be stored and protected. In other words, the residence time of unwanted water in an ecosystem should be as short as possible; while the detention time of wanted water (or

The idea of SPP for lake and reservoir water management is new, but this does not mean that the similar strategy has never been applied by far. In this section, we will discuss two cases to show that if SPP is not applied, the water related problems cannot be solved, while

In 1854 Dr John Snow demonstrated the connection between water supply and Cholera as shown in Fig. 4. Several years later, Thomas Hawksley in Nottingham suggested that water

Here the suggestion of pipe transport implied the idea of "separation, prevention and protection". Like the enclosed levee shown in Fig. 3, the pipe can *separate* clean water from the polluted water, and only clean water is allowed to enter the pipe network; likewise, the pipe protects the clean water inside the system and prevents the external pollutions. Consequently, the problem of waterborne illness death rate like Cholera, typhoid fever and dysentery had rapidly dropped to a very low level as shown in Fig. 5. This is probably the first time in history using the strategy of SPP for water resources management, and the

However, for large water system, so far there is no direct example of SPP strategy in application. Sometimes, people were forced to adapt the strategy of SPP to solve their problems. One of the examples is the Sanmenxia Reservoir in the middle reach of Yellow River, China. Yellow River basin is one of the largest basins in the world, and it is notorious in the world for high sediment transport rate in the middle reach. Between 1919 and 1960, the measured data at Sanmenxia Station showed that the mean annual runoff was 42.3×109 m3 and the long-term average annual sediment load was 1.57×109 t with the average

Sanmenxia Reservoir is created by the Sanmenxia dam. It is a large-scale multipurpose project, and the first one constructed on the main stream of the Yellow River. The construction of the dam was started in 1957, and the impoundment of water commenced in September 1960. The dam height is 106m at the pool level 323m with the storage capacity of

loss of lake water.

3.6×109 m3.

clean water) should be as long as possible.

**3. Successful cases by applying SPP strategy (too turbid)** 

if the strategy is applied, all problems become solvable.

supply systems should be piped to prevent external pollution.

concept of pipe water has been widely accepted in the world since then.

concentration of the river water being 49.8 kg/m3, the highest in the world.

Fig. 4. Dr. John Snow and the map he used in 1854 to identify the source of cholera; this discover leads to the first application of SPP strategy in water management

Fig. 5. Death rate of human being in the history, indicating the application of SPP could immediately reduce people's death rate

In its planning stage, engineers and decision makers used the same practice as they did for other reservoirs, i.e., no special measures had been taken to separate incoming water based on its quality, and nothing had been done to protect the reservoir water and to prevent external high turbidity water. Consequently the reservoir storage capacity was decreasing at an astonishing rate in the reservoir, which caused the unacceptable negative impact of rapid development of backwater sediment deposition. In 4 years time, the accumulative sediment silted in the reservoir reached alarming level, i.e., 4.44 ×109 m3, in other words, the reservoir's storage capacity had almost totally lost. Under such circumstance, engineers were forced to reconsider the strategy of water management, and the dam had to be reconstructed to minimize the adverse effect of reservoir sedimentation.

Novel SPP Water Management Strategy and Its Applications 249

This lake annually receives 173 million tons of sediment, 83% of which are carried into the lake from the Yangtze River, and 17% from other inflow rivers. Over the past 150 years, the lake area has reduced from about 6000km2 to about 2600km2 due to both natural siltation and human activity, consequently flood modulation of the lake capacity has been reduced significantly from about 30km3 in 1949 to 17km3 in 1995, about 50% of the lake's capacity has been silted. It is certain that the lake will continue to shrink, and in the near future it may serve only as a river channel during the non-flood reasons (Du et al. 2001). In another 50-100

Similar to other plain lakes, Dongting Lake has suffered many problems, if not solved properly, these problems may cause serious consequences to environment and bring about huge economic and life loss. These problems can be summarized as flood disasters in wet seasons (too much), water shortage for the ecosystem in dry seasons (too little), lake's

Apart from too much and too turbid problems, the lake water was polluted by the incoming wastewater due to rapid industrial development and population growth and agriculture fertilization. In this fertile "land of fish and rice", farmers every year use 18k tons of pesticide and 1700k tons excessive fertilizer, which flows into the lake via the rivers. After 1990s eutrophication tendency has been accelerated, according to the monitoring data, 1996-

2005 main pollutants are total phosphorus and total nitrogen (Guo et al., 2007). Li et al (2009) summarized the problems in the Donting Lake area as a chain:

space shrinkage flood level raised and flood disaster aggravated. Disaster in dry seasons : sedimentation marshland expansion water

Disaster in wet seasons : sedimentation marshland expansion water

shrinkage water pollution and fish resource depletion wetland and

→ →

The average reoccurrence interval (ARI) of flood disaster was 83 years from 276 B.C.-1525, and ARI = 20 years from 1525-1853; ARI = 5 years from 1853-1949 and ARI = 4 year from 1949-2000, recently this area suffers the flood disaster almost every year. Obviously this is caused by the sedimentation that keeps reducing the lake's capability for flood retention

All problems that the lake is facing can be well solved if the proposed SPP strategy is applied as shown in Fig. 6, in which the length of inner levee is about 240km. This is feasible

*1) Sedimentation*: in the current condition, almost all incoming sediment particles are deposited in the lake, i.e., 1730 million tons of sediment, and the lake functions like a sedimentation tank where the clean water run out of the tank. But with the inner dike, the incoming flow can be separated into wanted/unwanted waters, i.e., high turbid but safe floodwater will by-pass the lake and drain to the downstream. Only a small part of excessive floodwater is allowed to enter the lake, which can mitigate the flood disaster, and the majority of the water stored in the lake comes from the falling limb in the hydrograph shown in Fig. 2, thus clean and low turbid water is stored. Currently the lake's storage capacity is only 1/10 of the annual incoming water volume, if SPP is used and then the

→ →

→ →

years, this lake may totally disappear if there is no human's interference.

shrinkage (too turbidity) and water pollution (too dirty).

→

biodiversity reduction.

space

(Yang, 2004).

because:

The engineers and decision makers realized that there was no hope to solve the sedimentation problem without separation, then they divided the dam's operation into two time periods or two different modes of operation:


After the separation, the new design was found effective, till now, the dam is still providing the basin with flood control, irrigation, and hydropower generation, even though some benefits are lower than the original design. The engineering experiences and management practices of Sanmenxia Dam are valuable assets to the sustainable management of reservoirs/lakes on sediment-laden or nutrient-rich rivers. It can be seen that the above operation strategy is similar to the SPP introduced in this chapter as the unwanted water (high turbid floodwater) has a short residence time in the reservoir, and the clean water in non-flood season (wanted water) has a relative long residence time for the eco-system. This project not only demonstrated the perils of existing water management, but also demonstrated that a sediment balance may be achieved across an impounded reach even in a large reservoir built on a river with an extremely high sediment load.
