基于乡镇尺度的旱灾风险区划研究——以贵州播州区为例

Risk Zoning of Drought Disaster Based on Township Scale——A Case Study of Banzhou District of Guizhou

贵州是全国唯一没有平原支撑的喀斯特山地省份,因其特殊的地理位置、气候特征和下垫面性质,干旱灾害频发。为掌握干旱灾害风险分布情况及分布规律,将风险区划单元进一步延伸至乡镇,以指导各乡镇防旱抗旱工作高效开展。以贵州省播州区为对象,以乡镇为区划单元,分析和筛选干旱灾害风险代表性指标。基于自然灾害风险理论和GIS技术构建干旱灾害风险区划模型,开展乡镇尺度的干旱灾害风险区划研究。结果表明,播州区各乡镇干旱灾害风险等级以中风险及以下为主,占比60%,中高风险区和高风险区累积占比为40%。干旱灾害风险高的乡镇主要分布在播州区的东部、南部和西部。多年平均降水量可以反映干旱灾害危险性。林草覆盖率高的乡镇的地形条件较差,旱地占比较高,干旱灾害风险一般较高。地形条件好是干旱灾害风险低的必要条件。

Guizhou is the only karst mountainous province in China that is not supported by plains,and due to its special geographical location,climatic characteristics and underlying surface nature,drought disasters are frequent.In order to grasp the distribution and distribution law of drought disaster risk,the risk zoning units are further extended to townships to guide the efficient implementation of drought prevention and drought control in each township.Taking Banzhou District of Guizhou Province as the target and townships as the zoning units,the representative indicators of drought disaster risk were analyzed and screened.Based on natural disaster risk theory and GIS technology,a drought disaster risk zoning model was constructed,and the research on drought disaster risk zoning at the township scale was carried out.The results showed that the drought disaster risk level of each township in Banzhou District was mainly medium risk or below,accounting for 60%,and the cumulative proportion of medium-high risk areas and high risk areas was 40%.Townships with high risk of drought are mainly located in the eastern,southern and western parts of Banzhou District.Average annual precipitation can reflect the risk of drought disasters.Townships with high forest and grass coverage have poor topographic conditions,and the proportion of dry land is relatively high,so the risk of drought disaster is generally higher.Good topographic conditions are necessary for low risk of drought disasters.