3.1 Background information

This section evaluates the Chenhang reservoir water supply system resilience under the salt tide hazards in the estuary of Yangtze River. The formal definition of salt tide is the emergency situation that chloride concentrations in water body exceed the national standard level (250 mg per liter of water). Salt tide destroys the quality of water, results in soil salinization in coastal areas and cities, and has negative impacts on production and human daily life. Recently, salt tide has already become one of the most internationally concerned disasters of coastal cities. The invasion of saltwater during salt tide will limit the access of high-quality municipal and industrial water and will cause water shortage and scheduling problems in some megacities of China located in estuarine and coastal areas, such as Shanghai. Thus, water shortage problem has become one of the main obstacles that obstructs the construction of eco-city and sustainable development. By experience, the intensity of salt tide intrusion changes with the period of tides, showing its periodic properties. In general, September to April next year is the period of time influenced by salt tide of water intake in Yangtze River. Each intrusion of salt tide lasts for 6–7 days. Since there exist multiple factors that affect the duration and extent of hazards (e.g., Yangtze River hydrology, chase traffic, weather, and wind), it is usually difficult to make detailed and accurate prediction for each intrusion. In recent years, the hazards have become more severe in the following aspects: long intrusion duration, high frequency, short interval time between intrusions, and independence of Yangtze River runoffs. Given the fact that the "Three Gorges Project" increased the ability to implement different water strategies at the upstream of Yangtze River, the extreme hydrological hazards occurred more frequently, which make the research on how salt tide influences the water supply system more practical and crucial [38–40].

According to chemistry knowledge, physical and chemical contaminates such as chloride concentration, ammonia, oxygen consumption, and total iron play a role as indicators to show the degree of salt tide level. These indicators reach peak values during December to February [41]. Accordingly, the whole period can be categorized into three different periods:

3.2 Resilience evaluation results

DOI: http://dx.doi.org/10.5772/intechopen.82748

this case study are shown in Table 1.

Absorptive capacity M & E R Protection of wetlands and watersheds

BE & I Robustness and fortification

E Income and poverty

G & I Strong leadership

S & WB Population composition

Table 1.

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Indicators for water supply system.

E Insurance and social welfare G & I Efficient management of resources

S & WB Degree of connectedness across community groups E Investment in green jobs and green economy

G & I Decentralized responsibilities and resources

Adaptive capacity M & E R Material and resource management

Drills and exercises Recovery capacity M & E R Ecosystem monitoring and protection

3.2.1 ANP model

The resilience evaluation results are presented and analyzed in this subsection.

Machine Learning-Based Method for Urban Lifeline System Resilience Assessment in GIS

In Section 2, the MSEBG indicator framework for system resilience and ANP model were exhaustively introduced. The indicators selected from the experts for

In this case study, 50 experts were involved. Those experts are chosen based on the selection method proposed in [42]. Half of the experts are professional technicians from lifeline system industry or experts in the field of system resilience, and another half of the experts are part-time college students majoring in Environmental Engineering and Urban Design. With solid technical and practical backgrounds,

Availability and accessibility of resources (water)

Spatial distribution of critical infrastructure

Understanding risk patterns and trends

Stability of prices and incomes and property value

S & WB Place attachment and sense of community and pride

BE & I Redundancy of critical infrastructure, facilities, and stocks

Protection of wetlands and watersheds

Past experience with disaster recovery

Regular monitoring, maintenance, and upgrade of critical infrastructure

Consolidation of critical utilities and collaboration between utility providers Diverse and reliable information and communication technology (ICT) networks


The goal of this case study is to study the system capacities in terms of preparation for salt tide hazards, facing salt tide hazards, and recovering from salt tide hazards. Period I is the preparation period, when the salt tides gradually affect the water supply system. In Period III, the recovery phase would occur, after the severe disturbances of salt tide. Intuitively, for Period I, decision-makers should focus more on increasing the adaptive capacity of system when prevention and emergency are crucial to system against increasing salinity. In Period II, absorptive capacity should be emphasized, since the system needs to absorb perturbations and minimizes the consequence when contaminants immediately reach the peak. In Period III, recovery capacity is more important indicator when water supply system needs redesigning and rebuilding. Thus, for each period, the decision-making process can be implemented dynamically, and the weight evaluations of indicators and clustering results can be derived step by step.

In the studied area, Chenhang reservoir supplies water to districts (e.g., Baoshan, Jiading, Putuo, Zhabei, and Hongkou) and towns (e.g., Gaodong, Gaoqiao, and Gaoxing inside Pudong New District) in Shanghai. The whole study region is zoned into 29 communities on the basis of administrative divisions shown in Figure 2. A unique FID number is assigned to each community.

Figure 2. Basic GIS Layer for Chenhang reservoir water supply system.

Machine Learning-Based Method for Urban Lifeline System Resilience Assessment in GIS DOI: http://dx.doi.org/10.5772/intechopen.82748
