Flood Forecasting of Fengle River Basin on Unit Hydrograph Method
Abstract: To calculate ground net rainfall runoff, unit hydrograph method is one of the common methods for flood simulation and prediction. Taking Fengle River basin as a study case, 30 floods were selected based on data of its rainfall, flow and evaporation from 1984 to 2013. The Xinanjiang model was used to calculate the runoff and the separate water sources. Considering surface runoff and interflow as the direct runoff, unit hydrograph and the linear reservoir methods were adopted to simulate the confluence process of the direct runoff and underground runoff respectively. Then flood forecasting model for Fengle River basin was established. With the goal of minimizing the average absolute error between the calculated runoff depths with Xinanjiang model and the observed runoff depths of 14 floods as calibrated samples, the genetic algorithm was adopted to calibrate the parameters of Xinanjiang model. The unit hydrograph of flood confluence of direct runoff was quantified by the method based on the combination of analytical and trial and error approaches. Then 30 floods were simulated with the unit hydrograph acquired through flood data of No. 980915. According to the results, the average relative error of the runoff depth, the error of average flood peak and the peak time of 14 calibrated floods are 7%, 8% and 2.57 h respectively, with the qualification rate are 93%, 93% and 86% respectively, and the average deterministic coefficient is 0.91. The error of the runoff depth, flood peak and the peak time of the 16 validated floods are 8%, 9% and 3.38 h respectively, with the qualification rate are 88%, 94% and 88% respectively, and the average deterministic coefficient is 0.89. Practical applications of the flood forecasting for Fengle River water- shed show that, the model based on the Xinanjiang model and the unit hydrograph can be used to forecast the flood occurred within the watershed, and reaches to a high accuracy. However, the accuracy of concentration calculation of small floods with the unit hydrograph acquired through big flood data usually is lower than those big floods, and vice versa. So unit hydrograph should be calibrated with different rainfall intensities, then using different unit hydrograph to forecast flood processes according to their corresponding precipitation amounts.
文章引用: 宗雪玮 , 周玉良 , 王玉虎 , 沈 捷 , 金菊良 , 周 平 (2016) 基于经验单位线的丰乐河流域洪水预报。 水资源研究， 5， 211-221. doi: 10.12677/JWRR.2016.53027
 阚光远, 刘志雨, 李致家, 姚成, 周赛. 新安江产流模型与改进的BP汇流模型耦合应用[J]. 水科学进展, 2012, 23(1): 21-28. KAN Guangyuan, LIU Zhiyu, LI Zhijia, YAO Cheng and ZHOU Sai. Coupling Xinanjiang runoff generation model with im-proved BP flow concentration model. Advances in Water Science, 2012, 23(1): 21-28. (in Chinese)
 邹文安, 任建业. 地区综合法在洪水设计中的应用[J]. 水资源研究, 2012, 33(2): 32-35. ZOU Wenan, REN Jianye. Application of method of regional synthesized in flood design. Journal of Water Resources Research, 2012, 33(2): 32-35. (in Chinese)
MUHAMMAD, M. A., ABDUL, R. G. and SAJJAD, A. Estimation of Clark’s instantaneous unit hydrograph parameters and development of direct surface runoff hydrograph. Water Resources Management, 2009, 23(12): 2417-2435.
ABDUL, R. G., MUHAMMAD, M. A., HASHIM, N. H., et al. De-velopment of geomorphologic instantaneous unit hydrograph for a large watershed. Environmental Monitoring and Assessment, 2012, 184(5): 3153-3163.
 徐宗学, 程磊. 分布式水文模型研究与应用进展[J]. 水利学报, 2010, 41(9): 1009-1017. XU Zongxue, CHENG Lei. Progress on studies and applications of the distributed hydrological models. Journal of Hydraulic Engineering, 2010, 41(9):1009-1017. (in Chinese)
 金菊良, 丁晶, 魏一鸣. 瞬时单位线的优化估计[J]. 水力发电学报, 2003(1): 70-75. JIN Juliang, DING Jing and WEI Yiming. Optimal estimation of instantaneous unit hydrograph. Journal of Hydroelectric En-gineering, 2003(1): 70-75. (in Chinese)
DONG, S. H. Genetic algorithm based parameter estimation of nash model. Water Resources Management, 2008, 22(4): 525- 533.
 柏绍光, 黄英, 方绍东, 等. 纵向岭谷区小流域洪水汇流参数外延分析[J]. 水资源研究, 2007, 28(1): 18-20. BAI Shaoguang, HUANG Ying, FANG Shaodong and LI Zishun. Analysis of LRGR small basin flood confluence parameters extension. Journal of Water Resources, 2007, 28(1): 18-20. (in Chinese)
 乐红玲, 张萍霞, 王船海, 等. 平原河网区坡面汇流分布式单位线研究[J]. 水电能源科学, 2015, 33(2): 25-28. LE Hongling, ZHANG Pingxia, WANG Chuanhai, LIU Yuanyuan and WANG Yan. Research of distributed unit hydrograph of overland flow concentration in plain river network region. Water Resources and Power, 2015, 33(2): 25-28. (in Chinese)
 姚蕾, 梁忠民, 王军, 等. Nash汇流模型在无资料地区的应用[J]. 水电能源科学, 2014, 32(2): 23-26. YAO Lei, LIANG Zhongmin, WANG Jun and HU Yiming. Application of nash model in ungauged basin. Water Resources and Power, 2014, 32(2): 23-26. (in Chinese)
 江龙, 黄诗峰, 金菊良, 等. 基于GIS的安徽省淮河流域1978年历史大旱模拟与评估[J]. 水电能源科学, 2014, 32(6): 1-4. JIANG Long, HUANG Shifeng, JIN Juliang, FEI Zhenyu and OUYANG Wei. GIS-based simulation and assessment of histor-ical drought in 1978 of Huaihe River Basin of Anhui Province. Water Resources and Power, 2014, 32(6): 1-4. (in Chinese)
 杨自坤, 孔燕. 新安江三水源模型在横江洪水预报中的应用[J]. 水资源研究, 2010, 31(1): 36-38, 48. YANG Zikun, KONG Yan. Flood forecasting based on three sources Xin’anjiang Model in Heng River. Journal of Water Re-sources, 2010, 31(1): 36-38, 48. (in Chinese)
 金菊良, 杨晓华, 丁晶. 基于实数编码的加速遗传算法[J]. 四川大学学报(工程科学版), 2000, 32(4): 20-24. JIN Juliang, YANG Xiaohua, DING Jing. Real coding based acceleration genetic algorithm. Journal of Sichuan University (Engineering Science Edition), 2000, 32(4): 20-24. (in Chinese)
 徐磊磊, 刘敬林, 金昌杰, 王安志, 关德新, 吴家兵, 袁凤辉. 水文过程的基流分割方法研究进展[J]. 应用生态学报, 2011, 22(11): 3073-3080. XU Leilei, LIU Jinglin, JIN Changjie, WANG Anzhi, GUAN Dexin, WU Jiabing and YUAN Fenghui. Baseflow separation methods in hydrological process research: A review. Chinese Journal of Applied Ecology, 2011, 22(11): 3073-3080. (in Chi-nese)
 詹道江. 工程水文学[M]. 北京: 中国水利水电出版社, 2010: 87-96. ZHAN Daojiang. Engineering hydrology. Beijing: China Water & Power Press, 2010: 87-96. (in Chinese)
 翟丽妮, 梅亚东, 孔凡哲. 单位线方法在沿渡河流域的应用研究[J]. 中国农村水利水电, 2007(9): 16-18, 22. ZHAI Lini, MEI Yadong, KONG Fanzhe. Application of unit hydrograph method in the Yandu River Basin. China Rural Water and Hydropower, 2007(9): 16-18, 22. (in Chinese)