系统搜集了中国590个雨量站和383个水文站1956~2000年长序列月降水量与月径流量资料,及1978~2000年全国各省、自治区的旱涝受灾与成灾面积、灌区面积、已建水库库容等数据资料,全面分析了地表径流时空演变特征以及农业旱涝灾害的时空分布特征,并分析了其原因及可能影响,研究结果表明,中国北方降水减少,其中山东和黄河中游地区的降水量减小最显著。另外,冬季降水增加明显,而春秋季降水减少明显,极易导致春秋旱灾;北方地区降水减少是造成地表径流量减小的主要原因,农业灌溉进一步加剧地表径流量减小,南方径流量的增加主要是由降水量增加引起的;降水时空分布不均匀造成水资源分布不均,进而造成大部分地区农业受旱涝灾害面积呈增加趋势,其中旱灾受灾面积远大于水灾的受灾面积;农村水利基础设施(灌区、水库等)能提高地区的抗旱能力,但是对洪涝灾害的影响没有旱灾那么明显。节水灌溉技术的推广应用是北方地区在水资源短缺的前提下保证农业生产稳定的重要措施。
Changes of water resources in China are the key scientific problem in terms of sustainable development of agriculture and social security. Based on long-term hydro-meteorological dataset, i.e. daily precipita- tion data from 590 rainfall gauging stations and monthly streamflow from 383 hydrological stations covering 1956-2000 over China, water resources in China are thoroughly evaluated. Impacts of human activities, the agricultural irrigation in this study, on water resources are also analyzed. Besides, the data concerning the flood- and drought-affected and the flood- and drought-destroyed agricultural fields are also collected and analyzed with Mann-kendall and Kriging interpolationaim to discuss the implications of precipitation changes and streamflow variations on agriculture in China. This study produced important and novel conclusions: O decreasing precipitation is found in north China, particularly in the Shandong and the middle Yellow River. The south China is dominated by increasing precipitation. In addition, decreasing precipitation is prevailing in spring and autumn which may easily cause droughts in spring and autumn. The winter is characterized by in- creasing precipitation. (2) Decreasing surface streamflow is the result of decreasing precipitation. The agricultural irrigation further intensifies the decreasing magnitude of streamflow in north China. This result further corroborates the tremendous human influences on water resources in north China. (3) Uneven distribution of precipitation leads to uneven spatial patterns of water resources over China. Agricultural activities in China are mostly under the risk of drought and flood hazards. Drought hazards may play the dominant role in the loss of agricultural production. (4) the irrigation facilities are urgently calling for great concerns. Besides, water-saving agriculture is also the major effective way to mitigate water shortage due to climate changes and intensifying human interference with water resource system of China.