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Spatial multicriteria decision analysis of flood risks in aging-dam management in China: a framework and case study.

Yang M, Qian X, Zhang Y, Sheng J, Shen D, Ge Y - Int J Environ Res Public Health (2011)

Bottom Line: Approximately 30,000 dams in China are aging and are considered to be high-level risks.Based on the theories of spatial multicriteria decision analysis, this report generalizes a framework consisting of scenario definition, problem structuring, criteria construction, spatial quantification of criteria, criteria weighting, decision rules, sensitivity analyses, and scenario appraisal.With adjustments and improvement to the specific methods (according to the circumstances and available data) this framework may be applied to other sites.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, China. yngjyangmeng@gmail.com

ABSTRACT
Approximately 30,000 dams in China are aging and are considered to be high-level risks. Developing a framework for analyzing spatial multicriteria flood risk is crucial to ranking management scenarios for these dams, especially in densely populated areas. Based on the theories of spatial multicriteria decision analysis, this report generalizes a framework consisting of scenario definition, problem structuring, criteria construction, spatial quantification of criteria, criteria weighting, decision rules, sensitivity analyses, and scenario appraisal. The framework is presented in detail by using a case study to rank dam rehabilitation, decommissioning and existing-condition scenarios. The results show that there was a serious inundation, and that a dam rehabilitation scenario could reduce the multicriteria flood risk by 0.25 in the most affected areas; this indicates a mean risk decrease of less than 23%. Although increased risk (<0.20) was found for some residential and commercial buildings, if the dam were to be decommissioned, the mean risk would not be greater than the current existing risk, indicating that the dam rehabilitation scenario had a higher rank for decreasing the flood risk than the decommissioning scenario, but that dam rehabilitation alone might be of little help in abating flood risk. With adjustments and improvement to the specific methods (according to the circumstances and available data) this framework may be applied to other sites.

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Related in: MedlinePlus

(a) Flood risk of each indicator and (b) multicriteria flood risk under existing conditions. Economic-loss risk (yuan/year/cell) and population at risk (person/year/cell) were classified into the three following ranges: 1 (2 < economic loss risk < 100 or population at risk < 0.002); 2 (100 ≤ economic loss risk < 228 or 0.002 ≤ population at risk < 0.007); and 3 (228 ≤ economic loss risk ≤ 490 or 0.007 ≤ population at risk < 0.02).
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f7-ijerph-08-01368: (a) Flood risk of each indicator and (b) multicriteria flood risk under existing conditions. Economic-loss risk (yuan/year/cell) and population at risk (person/year/cell) were classified into the three following ranges: 1 (2 < economic loss risk < 100 or population at risk < 0.002); 2 (100 ≤ economic loss risk < 228 or 0.002 ≤ population at risk < 0.007); and 3 (228 ≤ economic loss risk ≤ 490 or 0.007 ≤ population at risk < 0.02).

Mentions: For each of the five indicators, a separate risk map of the existing condition was computed based on damaging water depths. The spatial patterns of economic-loss risks and populations at risk in residential buildings overlapped, so the risks of the two indicators were combined and classified into three ranges (Figure 7a). The highest risk (economic loss risk > 228 yuan/year/cell; population at risk > 0.007 person/year/cell) was found in the residential areas (Figure 7a) including Shanshui and the Bali Residential Community (Figure 2). Low economic-loss risk (values from 2 to 100 yuan/year/cell) was distributed in the western and northern parts of the Chuzhou High-tech Zone along Fengle Road (Figures 2 and 7a). The social hot spots, including the municipal administration center and the blood bank (Figure 2), were affected in two flood events (Figures 6a and b); hence, the inundated probability per year was 0.022 (Figure 7a). Most of the inundated areas with erosion potential were also affected in both of the flood events and thus had erosion risks of 0.022. A section of the Jinghu Railway (Figure 2) of approximately 600 m might also be inundated (with a probability of 0.022 per year). The areas without flood risk (e.g. that are not vulnerable to flooding) include impervious areas (except roads) and submergence-tolerant grassland.


Spatial multicriteria decision analysis of flood risks in aging-dam management in China: a framework and case study.

Yang M, Qian X, Zhang Y, Sheng J, Shen D, Ge Y - Int J Environ Res Public Health (2011)

(a) Flood risk of each indicator and (b) multicriteria flood risk under existing conditions. Economic-loss risk (yuan/year/cell) and population at risk (person/year/cell) were classified into the three following ranges: 1 (2 < economic loss risk < 100 or population at risk < 0.002); 2 (100 ≤ economic loss risk < 228 or 0.002 ≤ population at risk < 0.007); and 3 (228 ≤ economic loss risk ≤ 490 or 0.007 ≤ population at risk < 0.02).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3108115&req=5

f7-ijerph-08-01368: (a) Flood risk of each indicator and (b) multicriteria flood risk under existing conditions. Economic-loss risk (yuan/year/cell) and population at risk (person/year/cell) were classified into the three following ranges: 1 (2 < economic loss risk < 100 or population at risk < 0.002); 2 (100 ≤ economic loss risk < 228 or 0.002 ≤ population at risk < 0.007); and 3 (228 ≤ economic loss risk ≤ 490 or 0.007 ≤ population at risk < 0.02).
Mentions: For each of the five indicators, a separate risk map of the existing condition was computed based on damaging water depths. The spatial patterns of economic-loss risks and populations at risk in residential buildings overlapped, so the risks of the two indicators were combined and classified into three ranges (Figure 7a). The highest risk (economic loss risk > 228 yuan/year/cell; population at risk > 0.007 person/year/cell) was found in the residential areas (Figure 7a) including Shanshui and the Bali Residential Community (Figure 2). Low economic-loss risk (values from 2 to 100 yuan/year/cell) was distributed in the western and northern parts of the Chuzhou High-tech Zone along Fengle Road (Figures 2 and 7a). The social hot spots, including the municipal administration center and the blood bank (Figure 2), were affected in two flood events (Figures 6a and b); hence, the inundated probability per year was 0.022 (Figure 7a). Most of the inundated areas with erosion potential were also affected in both of the flood events and thus had erosion risks of 0.022. A section of the Jinghu Railway (Figure 2) of approximately 600 m might also be inundated (with a probability of 0.022 per year). The areas without flood risk (e.g. that are not vulnerable to flooding) include impervious areas (except roads) and submergence-tolerant grassland.

Bottom Line: Approximately 30,000 dams in China are aging and are considered to be high-level risks.Based on the theories of spatial multicriteria decision analysis, this report generalizes a framework consisting of scenario definition, problem structuring, criteria construction, spatial quantification of criteria, criteria weighting, decision rules, sensitivity analyses, and scenario appraisal.With adjustments and improvement to the specific methods (according to the circumstances and available data) this framework may be applied to other sites.

View Article: PubMed Central - PubMed

Affiliation: State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing 210046, China. yngjyangmeng@gmail.com

ABSTRACT
Approximately 30,000 dams in China are aging and are considered to be high-level risks. Developing a framework for analyzing spatial multicriteria flood risk is crucial to ranking management scenarios for these dams, especially in densely populated areas. Based on the theories of spatial multicriteria decision analysis, this report generalizes a framework consisting of scenario definition, problem structuring, criteria construction, spatial quantification of criteria, criteria weighting, decision rules, sensitivity analyses, and scenario appraisal. The framework is presented in detail by using a case study to rank dam rehabilitation, decommissioning and existing-condition scenarios. The results show that there was a serious inundation, and that a dam rehabilitation scenario could reduce the multicriteria flood risk by 0.25 in the most affected areas; this indicates a mean risk decrease of less than 23%. Although increased risk (<0.20) was found for some residential and commercial buildings, if the dam were to be decommissioned, the mean risk would not be greater than the current existing risk, indicating that the dam rehabilitation scenario had a higher rank for decreasing the flood risk than the decommissioning scenario, but that dam rehabilitation alone might be of little help in abating flood risk. With adjustments and improvement to the specific methods (according to the circumstances and available data) this framework may be applied to other sites.

Show MeSH
Related in: MedlinePlus