华北低平原区降水与坑塘蓄水响应关系研究——以河北省南皮县为例

华北低平原区淡水资源短缺,坑塘水等非常规水资源的开发利用日益重要。明确坑塘蓄水在不同降水年型下作为灌溉水源的保障能力,研究该区域降水与地表坑塘蓄水的响应关系,对于农业多水源联合利用具有重要意义。论文以华北低平原区河北省南皮县为研究区,通过Cl^-和稳定同位素平衡法,计算了南皮县雨季降水对坑塘水的补给份额,并基于2013—2015年间的3期Landsat TM遥感数据,采用改进的归一化差异水体指数提取坑塘信息,分析不同降水年型下南皮县坑塘的蓄水能力及灌溉潜力。结果表明：坑塘蓄水除了接受地下水的补给,主要接受降水的补给,丰水年雨季降水对微小型、中小型坑塘的补给比例约占74.3%~86.0%,对大型坑塘的补给比例不足30%;坑塘主要以小于0.5 hm²的微小型坑塘为主,不同面积等级的坑塘数量及蓄水面积与降水的变化是一致的;其中,平水年、枯水年和丰水年坑塘蓄水量分别为1.49×10⁷、0.84×10⁷、1.90×10⁷ m³,随年降水量增大而增多。研究结果可为区域坑塘水资源的合理开发利用提供理论基础。

Study on the Relationship between Precipitation and Pond Water Storage in Lowland Area of North China Plain—A Case Study in Nanpi County,Hebei Province

It is important that developing and utilizing of unconventional water resources such as pond water in the lowland area of North China Plain due to the shortage of fresh water resource. Thus, making clear the storage capacity of pond as irrigation water resources in years with different amount of precipitation and studying the relationship between precipitation and pond water storage are of great significance to the usages of multiple water resources in agriculture. Taking Nanpi County in Hebei Province as study area, this paper used the methods of Cl^- and stable isotope balance to calculate the contribution of precipitation to pond water in rainy season. Besides, based on the Landsat TM remote sensing data during 2013-2015, the improved normalized difference water body index was used to extract the pond information and analyze the water storage capacity of ponds in Nanpi County in years with different amount of precipitation. The results showed that precipitation is the main source of pond water, and the groundwater was the second source. According to the calculation of Cl^- and stable isotope, precipitation accounts for 74.3%-86.0% of water supply for medium and small ponds during the rainy season in wet year, however, it accounts for only less than 30% of water supply for large ponds. The ponds are mainly small ponds with area less than 0.5 hm². The number and the water storage area of ponds with different areas changed with precipitation. The water storage capacity of ponds in flat water year, dry year and wet year were 1.49×10⁷, 0.84×10⁷ and 1.90×10⁷ m³, respectively. The results provide important infromation for the pond water management and utilization in the lowland area of North China Plain.