四川省小流域泥石流危险性评价
作者简介:熊俊楠(1981-),男,四川南充人,博士,副教授,主要从事地理信息系统与灾害风险分析方面的研究。E-mail: neu_xjn@163.com
收稿日期: 2017-06-30
要求修回日期: 2017-09-26
网络出版日期: 2017-12-25
基金资助
住房和城乡建设部科技计划项目(2016-K3-024)
国家安全生产监督管理总局科技项目(2014-3281)
西藏自治区科技支撑计划项目(省809)
西南石油大学启航计划项目(2014QHZ034)
Hazard Assessment of Debris Flow in Sichuan Province
Received date: 2017-06-30
Request revised date: 2017-09-26
Online published: 2017-12-25
Copyright
泥石流危险性评价是泥石流防灾减灾的重要内容。本文以四川省为研究区,以DEM为数据源,通过提取水流方向,计算汇流累积量,实现四川省小流域划分。基于收集的已查明泥石流流域资料,分析了泥石流孕灾环境与成灾特点,选择流域高差、流域面积为指标,建立基于能量条件的潜势泥石流流域判识模型,对划分的小流域进行判识,识别出7798个小流域具备泥石流发生所需能量条件,面积为31.1×104 km2,占四川省总面积的64.18 %。进而建立了泥石流危险性评价指标体系和可拓物元模型,开展了小流域泥石流危险性评价,划分了危险度等级,得到中度、高度、极高危险区的小流域个数分别为1946、1725和1002个,面积分别为9.1×104、7.7×104和3.4×104 km2,中度以上危险区面积共20.2×104 km²,占四川省总面积的41.67%。最后对评价结果可靠性和各等级泥石流危险区在各地市级行政区、各大流域的分布进行了分析。其结果对促进泥石流判识与危险性评价理论,区域泥石流防灾减灾与山区可持续发展等具有重要的理论和现实意义。
熊俊楠 , 韦方强 , 刘志奇 . 四川省小流域泥石流危险性评价[J]. 地球信息科学学报, 2017 , 19(12) : 1604 -1612 . DOI: 10.3724/SP.J.1047.2017.01604
Hazard assessment is important for the prevention and mitigation of debris flow disaster. This study takes Sichuan Province as the research area. Based on the DEM data, we realize the demarcation of the small watershed in Sichuan Province by extracting the direction of water flow and calculating the accumulation of the flow confluence. Based on the collected information of debris flow watershed, we selected the watershed elevation difference and watershed area as the indicators. The identification model of potential debris flow watershed based on the energy condition was built by analyzing the hazard-formative environment and characteristics of debris flow hazards. A total of 7798 small watersheds with the required energy conditions for debris flow occurring were identified by utilizing the established model among all the demarcated small watersheds, which is 31.1×104 km2 accounting for 64.18% of the total area of Sichuan Province. The indicator system of debris flow hazard risk assessment and the extension matter-element model were established from the energy condition of the debris flow occurring, the condition of the loose solid materials, the precipitation condition and the condition of human activity. These determine the weights of the assessment factors, of dividing the grade of the hazard risk, by which it classifies the hazard risk degree of small watershed debris flow. The number of the moderate, high and very high hazard degree is 1946, 1725 and 1002, with an area of 9.1×104 km2, 7.7×104 km2 and 3.4×104 km2, respectively. The total area of moderate hazard areas is 20.2×104 km², accounting for 41.67% of the total area of Sichuan Province. Finally, the analyses were made for the reliability of assessment results and the distribution of the different hazard degree of debris flow areas in different municipal administrative districts and the major river valleys. All the known small watershed of very high hazard degree are identified as debris flow watersheds. The 896 watersheds of moderate hazard degree do not belong to the identified debris flow and 1233 watersheds of high hazard degree do not belong to the identified debris flow, either. They are the key area for disaster prevention and reduction in Sichuan province in the next few years. The results of the analyses have the great theoretical and practical significance for enhancing the debris flow identification, the prevention and mitigation of regional debris flow disaster. The sustainable development of mountainous areas and also the theory of the risk assessment of debris flow hazard.
Fig. 1 Hillshade and gullies of debris flows in the study area图1 研究区地势特征及泥石流沟分布 |
Fig. 2 Relationship between watershed area and relative height of unit area图2 泥石流流域面积与单位面积相对高度关系图 |
Fig. 3 The identification results of potential debris flow图3 潜势泥石流流域判识结果 |
Tab. 1 Correlation matrix between evaluation factors表1 评价因子间的相关系数 |
高差 | 沟床比降 | 断层密度 | 地震烈度 | 地层岩性 | 土地利用 | 平均降水 | 降水变差 | |
---|---|---|---|---|---|---|---|---|
高差 | 1.000 | 0.404 | 0.171 | 0.233 | -0.169 | -0.458 | 0.107 | 0.161 |
沟床比降 | 0.404 | 1.000 | 0.111 | 0.122 | -0.119 | -0.364 | 0.012 | 0.091 |
断层密度 | 0.171 | 0.111 | 1.000 | 0.157 | -0.119 | -0.140 | -0.052 | 0.000 |
地震烈度 | 0.233 | 0.122 | 0.157 | 1.000 | -0.119 | -0.200 | -0.173 | -0.105 |
地层岩性 | -0.169 | -0.112 | -0.119 | -0.119 | 1.000 | 0.273 | 0.396 | 0.195 |
土地利用 | -0.458 | -0.364 | -0.140 | -0.200 | 0.273 | 1.000 | 0.133 | -0.002 |
平均降水 | 0.107 | 0.012 | -0.052 | -0.173 | 0.396 | 0.133 | 1.000 | 0.395 |
降水变差 | 0.161 | 0.091 | 0.000 | -0.105 | 0.195 | -0.002 | 0.395 | 1.000 |
Tab. 2 Standard matter-element model for debris flow hazard assessment表2 泥石流危险性评价的标准物元模型 |
概率 | 流域单元特征 | 标准物元 |
---|---|---|
0-0.2 | 1. 断层密度/(m/km2):F=0 | |
2. 地层岩性:R=1 | ||
3. 地震烈度/°:0<E≤3 | ||
4. 年平均降水量/mm: Pmean<500, Pmean>1100 | ||
5. 降水量年际变差:Cv<0.1 | ||
6. 高差/m: H>3100, H≤100 | ||
7. 沟床比降/:S>650,S<50 | ||
8. 土地利用:0.05<L≤0.1 | ||
0.2-0.4 | 1. 断层密度/(m/km2):0<F≤0.15 | |
2. 地层岩性:R=2 | ||
3. 地震烈度/°:3<E≤6 | ||
4. 年平均降水量/mm: 500<Pmean≤600 1000<Pmean≤1100 | ||
5. 降水量年际变差:0.14<Cv≤0.16 | ||
6. 高差/m: 100<H≤300, 2500<H≤3100 | ||
7. 沟床比降/:500<S≤650 | ||
8. 土地利用:0.1<L≤0.15 | ||
0.4-0.6 | 1. 断层密度/(m/km2):0.15<F≤0.3 | |
2. 地层岩性:R=3 | ||
3. 地震烈度/°:6<E≤7 | ||
4. 年平均降水量/mm: 600<Pmean≤700, 900<Pmean≤1000 | ||
5. 降水量年际变差:0.1<Cv≤0.12 | ||
6. 高差/m: 300<H≤400, 1700<H≤2500 | ||
7. 沟床比降/:350<S≤500, | ||
8. 土地利用:0<L≤0.05 | ||
0.6-0.8 | 1. 断层密度/(m/km2): 0.3<F≤0.5 | |
2. 地层岩性:R=4 | ||
3. 地震烈度/°:7<E≤9 | ||
4. 年平均降水量/mm: 700<Pmean≤800 | ||
5. 降水量年际变差:Cv>0.16 | ||
6. 高差/m: 400<H≤600, 1400<H≤1700 | ||
7. 沟床比降/:150<S≤350 | ||
8. 土地利用:L>0.2 | ||
0.8-1 | 1. 断层密度/(m/km2):F>0.5 | |
2. 地层岩性:R=5 | ||
3. 地震烈度/°:9<E≤11 | ||
4. 年平均降水量/mm: 800<Pmean≤900 | ||
5. 降水量年际变差:0.12<Cv≤0.14 | ||
6. 高差/m:600<H≤1400 | ||
7. 沟床比降/:50<S≤150 | ||
8. 土地利用:0.15<L≤0.2 |
Tab. 3 Weighting coefficients of assessment factors of regional debris flow hazard表3 区域泥石流危险性评价因子权重表 |
类别 | 地面要素类 | 气象要素类 | |||||||
---|---|---|---|---|---|---|---|---|---|
断层密度 | 地层岩性 | 地震烈度 | 高差 | 沟床比降 | 土地利用 | 年平均降水量 | 降水量年际变差 | ||
各类权重 | 0.17 | 0.1 | 0.08 | 0.22 | 0.2 | 0.04 | 0.14 | 0.05 |
Tab. 4 Hazard degree classification of regional debris flow表4 区域泥石流危险度等级划分[5] |
区域泥石流危险度 | 危险度分区 | 泥石流活动特征 |
---|---|---|
0.0-0.2 | 极低危险区 | 基本无泥石流活动,没有泥石流灾难,安全区 |
0.2-0.4 | 低度危险区 | 能够发生小规模和低频率的泥石流,一般不会造成重大灾难和严重危害 |
0.4-0.6 | 中度危险区 | 能够间歇性发生中等规模的泥石流,较少造成重大灾难和严重危害 |
0.6-0.8 | 高度危险区 | 能够发生大规模和高频率的泥石流,可造成重大灾难和严重危害 |
0.8-1.0 | 极高危险区 | 能够发生巨大规模和特高频率的泥石流,可造成重大灾难和严重危害 |
Fig. 4 Hazard assessment results of debris flow图4 四川省泥石流危险性评价结果图 |
Tab. 5 The area of each hazard degree in all prefectures and cities表5 各市级行政区内不同等级危险区面积统计表(km²) |
市级行政区 | 极低 危险区 | 低度 危险区 | 中度 危险区 | 高度 危险区 | 极高 危险区 |
---|---|---|---|---|---|
成都市 | 8285 | 711 | 829 | 503 | 1777 |
自贡市 | 4376 | 0 | 0 | 0 | 0 |
攀枝花市 | 872 | 1260 | 1890 | 2157 | 1231 |
泸州市 | 6391 | 2949 | 1950 | 924 | 0 |
德阳市 | 4364 | 71 | 326 | 65 | 1093 |
绵阳市 | 10 355 | 346 | 4684 | 4237 | 567 |
广元市 | 8000 | 3436 | 2571 | 2182 | 14 |
遂宁市 | 5322 | 0 | 0 | 0 | 0 |
内江市 | 5003 | 5 | 0 | 0 | 0 |
乐山市 | 5435 | 1936 | 1378 | 3848 | 539 |
南充市 | 12516 | 50 | 0 | 0 | 0 |
眉山市 | 577 | 300 | 418 | 688 | 15 |
宜宾市 | 8095 | 3375 | 1733 | 49 | 0 |
广安市 | 4780 | 892 | 331 | 350 | 0 |
达州市 | 8587 | 6060 | 1548 | 375 | 4 |
雅安市 | 2337 | 852 | 2602 | 4335 | 4898 |
巴中市 | 6817 | 4373 | 461 | 635 | 0 |
资阳市 | 7922 | 15 | 4.56 | 0 | 0 |
阿坝藏族羌族自治州 | 32 373 | 18 952 | 20 387 | 8530 | 2493 |
甘孜藏族自治州 | 48 051 | 30 493 | 37 376 | 25 326 | 7188 |
凉山彝族自治州 | 7415 | 3397 | 12 677 | 22 338 | 14 356 |
The authors have declared that no competing interests exist.
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