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排序方式: 共有1284条查询结果,搜索用时 62 毫秒
1.
Carly E. Federman Durelle T. Scott Erich T. Hester 《Journal of the American Water Resources Association》2023,59(1):29-48
River flooding impacts human life and infrastructure, yet provides habitat and ecosystem services. Traditional flood control (e.g., levees, dams) reduces habitat and ecosystem services, and exacerbates flooding elsewhere. Floodplain restoration (i.e., bankfull floodplain reconnection and Stage 0) can also provide flood management, but has not been sufficiently evaluated for small frequent storms. We used 1D unsteady Hydrologic Engineering Center's River Analysis System to simulate small storms in a 5 km-long, second-order generic stream from the Chesapeake Bay watershed, and varied % channel restored (starting at the upstream end), restoration location, restoration bank height (distinguishes bankfull from Stage 0 restoration), and floodplain width/Manning's n. Stream restoration decreased (attenuated) peak flow up to 37% and increased floodplain exchange by up to 46%. Floodplain width and % channel restored had the largest impact on flood attenuation. The incremental effects of new restoration projects on flood attenuation were greatest when little prior restoration had occurred. By contrast, incremental effects on floodplain exchange were greatest in the presence of substantial prior restoration, setting up a tradeoff. A similar tradeoff was revealed between attenuation and exchange for project location, but not bank height or floodplain width. In particular, attenuation and exchange were always greater for Stage 0 than for bankfull floodplain restoration. Stage 0 thus may counteract human impacts such as urbanization. 相似文献
2.
利用TRMM(Tropical Rainfall Measuring Mission,TRMM)3B43月降水数据,并结合降水Z指数,研究朝鲜1998—2018年的降水和旱涝时空格局。结果表明:TRMM与站点观测降水数据有显著的相关性。朝鲜降水季节性特征明显,57.29%的降水集中在夏季,空间上自东北部沿海岸线向东南递增。朝鲜的区域综合旱涝等级基本处于正常状态,偏旱和偏涝发生的频率最高,其次是大旱和大涝,极旱和极涝发生的频率最低,夏季和冬季干旱发生最为频繁,而洪涝在秋季频发。朝鲜北部发生旱涝事件的频率明显高于南部,咸镜山脉和盖马高原是旱涝的多发地区,温泉平原则最不易受到旱涝影响。春季、夏季和秋季均呈现洪涝强度增强的趋势。夏季洪涝强度加剧的趋势明显,中北部地区通过95%的显著性检验。 相似文献
3.
Granular acid-activated neutralized red mud (AaN-RM) has been successfully prepared with good chemical stability and physical strength. However, its potential for industrial application remains unknown. Therefore, the performance of granular AaN-RM for phosphate recovery in a fixed-bed column was investigated. The results demonstrated that the phosphate adsorption performance of granular AaN-RM in a fixed-bed column was affected by various operational parameters, such as the bed depth, flow rate, initial solution pH and initial phosphate concentration. With the optimal empty-bed contact time (EBCT) of 24.27 min, the number of processed bed volumes and the phosphate adsorption capacity reached 496.95 and 84.80 mg/g, respectively. Then, the saturated fixed-bed column could be effectively regenerated with a 0.5 mol/L HCl solution. The desorption efficiency remained as high as 83.45% with a low weight loss of 3.57% in the fifth regeneration cycle. In addition, breakthrough curve modelling showed that a 5-9-1 feed-forward artificial neural network (ANN) could be effectively applied for the optimization of the fixed-bed adsorption system; the coefficient of determination (R2) and the root mean square error (RMSE) evaluated on the validation-testing data were 0.9987 and 0.0183, respectively. Therefore, granular AaN-RM fixed-bed adsorption exhibits promising potential for phosphate removal and recovery from polluted water. 相似文献
4.
5.
对原CODMn法测地表水二次取样体积进行了推导,建立了实际适用取样体积公式,具有一定的适用性。 相似文献
6.
Assessing land use impacts on flood processes in complex terrain by using GIS and modeling approach 总被引:1,自引:0,他引:1
Y. B. Liu F. De Smedt L. Hoffmann L. Pfister 《Environmental Modeling and Assessment》2005,9(4):227-235
A distributed hydrologic modeling and GIS approach is applied for the assessment of land use impact in the Steinsel sub-basin, Alzette, Grand-Duchy of Luxembourg. The assessment focuses on the runoff contributions from different land use classes and the potential impact of land use changes on runoff generation. The results show that the direct runoff from urban areas is dominant for a flood event compared with runoff from other land use areas in this catchment, and tends to increase for small floods and for the dry season floods, whereas the interflow from forested, pasture and agricultural field areas contributes to the recession flow. Significant variations in flood volume, peak discharge, time to the peak, etc., are found from the model simulation based on the three hypothetical land use change scenarios. 相似文献
7.
8.
Effects of acid deposition on forests in south China 总被引:1,自引:0,他引:1
1IntroductionWiththefastgrowingofmodernindustryandsharplyincreasingofenergyconsumptionprimarilycoal,airpolutionandaciddeposit... 相似文献
9.
洪水入海对养殖环境影响的数值分析 总被引:2,自引:0,他引:2
基于三维流体动力学和热力学原始方程 ,采用σ坐标变换技术 ,建立了三维斜压场数值模型。模型采用ADI格式求解连续方程和动量方程 ,采用FS法和TVD格式求解各标量方程 ,从而使模型的精度提高到二阶 ,并且节省运算时间。利用建立的三维斜压场数值模型 ,对鸭绿江洪水期形成的低盐水体的分布进行了数值模拟 ,进而分析了鸭绿江洪水入海对黄海北部海域的海水养殖业的可能影响。鸭绿江特大泄洪形成的超低盐混浊水体入侵 ,是筏养扇贝致死的主要原因。及时预报大洪水影响下的低盐水体分布 ,可有效地防止洪水污损灾害。 相似文献
10.
朱晓琳 《防灾技术高等专科学校学报》2006,8(2):25-27
“万里长江,险在荆江”,民国前期(1912-1927)荆江两岸地区水灾频仍.在荆江两岸地区1912-1927年洪水灾害相关资料的基础上,运用一般统计方法和理论分析了这一时期洪水灾害的若干特征,即普遍性、连续性、积累性和区域性四个特征.对洪水灾害基本特征及其规律的探讨至今对于有效的进行水患治理与防治仍有着深远的影响. 相似文献