3.2 Resilience evaluation results

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

## 3.2.1 ANP model

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 catego-

• Period I: September to December, when the chloride concentration in water

• Period II: December to February (next year), when the chloride concentration

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

abruptly reaches approximately the peak value (250–450 mg/L)

• Period III: From February to April, when salt tide recedes and chloride

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.

rized into three different periods:

accumulates up to 250 mg/L

Geographic Information Systems and Science

concentration returns to normal level

clustering results can be derived step by step.

Basic GIS Layer for Chenhang reservoir water supply system.

Figure 2.

50

In Section 2, the MSEBG indicator framework for system resilience and ANP model were exhaustively introduced. The indicators selected from the experts for this case study are shown in Table 1.

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,


Table 1. Indicators for water supply system. they can understand and evaluate system resilience and provide scores for the corresponding indicators.

The ANP model for this case study is presented in Figure 3. The connection arc shows the independent relationship between two indicators.
