长江上游坡耕地降雨径流蓄集利用效果评价

通过建立反映坡面降雨径流调控工程技术措施、拦截季节性降水、补充作物需水高峰期用水效果的综合评价指标体系,利用模糊多因素层次评价数学模型,对坡面降雨径流调控技术及其降雨径流蓄集和利用状况进行评价分析。计算结果表明,在具有季节性干旱缺水的坡耕地灌溉区域,在不同设计代表年份的降雨情况下均表现出良好的降雨径流蓄集利用效果。因此,通过修建雨水蓄集工程,实施坡面径流调控和水系的合理配置是很有必要的,同时也能为长江上游坡耕地整治与坡地高效生态农业的可持续发展提供科学依据和决策支持。     

不同坡度和前期土壤含水率条件下裸地降雨产流试验研究

坡度和前期土壤含水率是降雨产流过程的重要影响因素。为研究华北半干旱地区的降雨产流机制,采用人工模拟降雨的方法,进行了不同坡度(5°、10°和15°)和前期土壤含水率(0.20、0.25和0.30)条件下的降雨产流试验。结果表明:在整个降雨产流过程中,地表径流量随坡度和前期土壤含水率的增加而增大,累积径流量与产流历时呈线性函数关系;土壤入渗率和产流滞时均随前期土壤含水率和坡度的增加而减小,且前期土壤含水率对土壤入渗率和产流滞时的影响较坡度更加明显;Horton模型对降雨入渗关系的拟合结果优于Kostiakov和Philip模型。     

近47年来降水变化和人类活动对滦河流域年径流量的影响

近47年来,随着流域降水量的减少,以及水利工程的修建、林草地的减少等土地利用方式的改变,在气候变化和人类活动双重因素的作用下,滦河流域年径流量呈现出显著的减少趋势。现基于降水-径流经验统计模型的构建,定量评估了滦河流域降水变化和人类活动对该地区年径流量的影响程度。结果表明:①1983年以前,滦河流域年径流量受环境变化影响较小,1983年以后,年径流量受到气候变化和人类活动影响较为显著;②1984年-2006年期间,受人类活动影响所产生的年均减水量为11.97亿m3,占该时段减水量的84.42%,受降水变化所产生的年均减水量为2.21亿m3,占该时段减水量的15.58%,人类活动的贡献率远大于降水变化。     

城市非点源污染的初步探讨

非点源污染是造成环境污染的重要因素之一，是指溶解的或固体的污染物从非特定的地点，在降水和径流的冲刷作用下，通过径流过程汇入受纳水体，而引起的水体污染，是相应于点源的重要污染源类型。非点源污染的危害与严重性随着点源污染控制能力的提高而逐渐表现出来。介绍了城市非点源污染的国内外研究现状，分析比较了城市非点源污染的研究方法。通过实地采集水样与实验室化验，分析了由城市降雨径流造成水环境污染的程度、污染物类型和各污染物浓度随径流时间的变化过程，进行了初步的探讨，并提出了一些规律性结论。     

基于改进BP网络的日径流预报模型研究

针对常规BP算法收敛速度慢和难以获得全局最优的不足,将网络误差函数的改变量引入权值和偏移值的调整,采用自适应学习速率和自适应动量因子调整策略,建立了基于多层感知器神经网络(MLP-ANN)的水文预报模型.采用自相关函教(ACF)和交又相关函数(CCF)确定网络输入因子并使用试错法优化网络结构.以湖南省双牌水库日入库流量预测为应用实例,并将模拟结果与常规BP网络模型和新安江模型进行对比分析.结果表明,改进模型收敛速度快、预报精度高.     

The Influence of Model Structure on the Efficiency of Rainfall-Runoff Models: A Comparative Study for Some Catchments of Central India

The paper examines relative performance of six monthly rainfall-runoff models on 12 catchments located in different agro-climate zones of Central India. Study indicates that a water balance type model can reproduce the catchment behaviour in a better manner as compared to a statistical model and it is easier to model runoff for catchments with higher runoff factor. Also, a two-parameter model is found sufficient to represent the rainfall-runoff relationship of the catchment on a monthly scale.     

Rainfall-runoff simulation and flood forecasting for Huaihe Basin

The main purpose of this study was to forecast the inflow to Hongze Lake using the Xin＇anjiang rainfall-runoff model. The upper area of Hongze Lake in the Huaihe Basin was divided into 23 sub-basins, including the surface of Hongze Lake. The influence of reservoirs and gates on flood forecasting was considered in a practical and simple way. With a one-day time step, the linear and non-linear Muskingum method was used for channel flood routing, and the least-square regression model was used for real-time correction in flood forecasting. Representative historical data were collected for the model calibration. The hydrological model parameters for each sub-basin were calibrated individually, so the parameters of the Xin＇anjiang model were different for different sub-basins. This flood forecasting system was used in the real-time simulation of the large flood in 2005 and the results are satisfactory when compared with measured data from the flood.     

The hydrologic outcome of a Low Impact Development (LID) site including superposition with streamflow peaks

Hydrology plays a key role in mitigating environmental impacts with Stormwater Management (SWM). Site-level Low Impact Development (LID) is a promising approach but impeded by a lack of experience, performance metrics and comprehensive analysis. This study investigated the hydrologic performance of a small LID site (0.15 km²) including superposition with high flows of the receiving stream by monitoring precipitation, discharge and streamflow for 30 months. The results (73% event capture, 66–87% volume reduction, 39 L/ha/s peak discharge, 4.5% streamflow amplification) implied that site-level LID provides an alternative to conventional SWM even for unfavourable conditions. Weak performance related to underground storage, antecedent conditions, storm characteristics and freezing periods occurred seasonally; and a minimum storm capture volume could not be observed, but a maximum retention capacity. Future LID site designs should consider these characteristics and limitations, together with a differentiated analysis of a set of metrics for deducing environmental implications.     

基于运动波壤中流理论与无限边坡稳定分析理论的滑坡预测模型

滑坡往往发生在强降雨时期的陡峭山坡区域,建立滑坡预测模型是山坡地防灾重要策略之一.结合山坡运动波壤中流理论与无限边坡稳定分析理论,构建了降雨型浅层滑坡的预测模型.首先,根据运动波壤中流理论对坡面进行产汇流计算得到出口断面径流过程线及土壤蓄水量随时间与空间变化过程;然后,研究坡面出口处饱和水位随时间的变化特性;最后,根据...