单元嵌套网格产汇流理论

凭借"大数据"可以精细刻画降雨空间分布和下垫面空间变异性的优势,提出了"大数据"背景下考虑降雨空间分布和下垫面空间变异性对流域产汇流影响的计算方法,即单元嵌套网格剖分流域的方法。通过引入"网格水滴"的概念揭示了流域瞬时单位线的物理本质,对由RodriguezIturbe和Valdes所提出R-V地貌瞬时单位线理论进行补充,分析了等流时线法和单位线法的局限性,提出的单元嵌套网格产汇理论既克服了等流时线法和单位线法的缺点,也吸取了它们的优点,为在"大数据"支撑下统一等流时线和单位线法提供了可行性。     

红河流域径流演变分异及其特征

红河流域径流演变分异研究对于揭示流域径流的形成、演变规律及跨境水管理具有重要意义。选取红河流域9个代表站点,利用累积距平法、滑动t检验和Mann-Kendall-Sneyers法研究了红河流域的径流演变分异。结果表明,径流演变空间差异显著,各控制断面波动不一致;流域各站点(除大东勇站)均出现径流突变,但突变时间不一致,且越往下游,突变时间越晚;此外,各站点丰枯转化时段不一致。     

Trends and periodicities in observed temperature,precipitation and runoff in a desert catchment: case study for the Shiyang River Basin in Northwestern China

The Mann–Kendall test, wavelet analysis was used to analyse the long‐term trends and periodicities in temperature, precipitation and streamflow in China's Shiyang River Basin since 1950. The Principal components analysis (PCA) was used to quantify the impacts of climate change and human activities on water resources. The annual mean air temperature has increased, consistent with increasing global temperatures. The annual precipitation fluctuated but has generally increased since the 1990s. The air temperature and precipitation showed changes on periods ranging from 2 to 28 years. The correlation between annual runoff and precipitation variation was 0.61 (P < 0.05), indicating precipitation is the main source of the runoff. Human activities played the dominant role in the lower reaches, accounting for 58.5% of the total effect. The results have important implications for water resources management to support harmonisation of the relationship between humans and nature to combat the effect of climate.     

Treatment of log yard runoff in a couch grass infiltration wetland in Sweden

Sprinkling is often used in Scandinavia to protect round wood stored for industrial use from fungal and insect attack and drying cracks. Log yard runoff can be harmful for the water recipient due to eutrophication and oxygen depletion. A wetland system for treatment of log yard runoff is being evaluated in central Sweden. The purification capacity of a sloping couch grass (Elytrigia repens L.) field was examined when log yard runoff was applied to the field through a sprinkling system. Water samples were taken from groundwater pipes during four summer seasons (May to September, 2002–2005) and analysed for total organic carbon, total phosphorus (TP), total nitrogen and distillable phenols to evaluate the purification capacity of the infiltration wetland. Results from 2002 to 2004 were compared with results from 2005 when the irrigation intensity was considerably lower. Overall, the results showed good purification capacity although the concentrations of TP in the groundwater increased during 2005. The reduced hydraulic load did not increase purification.     

Effects of urbanisation on the quality of the urban runoff for Delhi watershed

The current paper is the first study to report quality of urban runoff, focusing on the diffuse sources contributing to pollutant loads in the Delhi watershed. The quality of stormwater runoff from the urban watershed of Delhi was evaluated to assess the effects of different land-use practices on pollutant concentrations. Six sites within the Delhi watershed with different land-use characteristics were selected. The microbial quality of the urban runoff from sub-catchments of Delhi watershed is very poor with Faecal Coliform (FC) levels varying between 6 and 7 log orders. There was a good correlation between the chemical and biological quality of urban runoff with land-use characteristics such as impervious land and population density. Except for chemical oxygen demand all other parameters in urban runoff were found to exceed the effluent discharge standards set by the National River Conservation Directorate (NRCD), India. The public health risks associated with exposure to urban runoff via different routes have also been qualitatively estimated.     

Pesticides in rain and roof runoff waters from an urban region

The levels of organonitrogen, organochlorine and organophosphorus pesticides were monitored in rain and roof runoff waters in Gdańsk (Poland) over a period of 6 months (October 2000 – March 2001). Buildings included in the study were of different ages, and covered with a variety of roofing materials. Samples were collected during the precipitation events. Pesticides were determined by gas chromatography combined with NPD and ECD detection. Bromofos, heptachlor epoxide and o,p′-DDE were detected the most often in the samples collected. In general, pesticide concentrations were higher in roof runoff than in rainwater. The type of the roofing material had a significant effect on the pesticide levels in runoff waters. The highest analyte levels were recorded in October and November, when the temperature was the highest.     

Laboratory analysis of the outflow and detention processes from modular tray-based blue roofs

ABSTRACT

Novel laboratory experiments were carried out to investigate the outflow process and the detention effects of a tray module of a blue roof (BR) system designed for runoff control from building roofs. The experiments revealed the outflow from the tray to decline during time, due to a number of complex dynamics occurring in proximity of the outlet orifice. The tests also showed the system to provide potential for relevant attenuation of the flow peak during inflow events (i.e. precipitation) of different magnitude. Based on regression analysis, an empirical relationship was developed for the evaluation of the tray outflow as a function of time, thus providing a tool for improved design of BRs. Finally, combination of the identified relationship with a routine for the water balance simulation of the tray was shown to describe reliably the detention process in the BR tray module.     

Bacterial contamination due to point and nonpoint source pollution in a rapidly growing urban center in an arid region

The distribution of bacterial contaminants (Escherichia coli and total coliforms) and nutrients (nitrogen and phosphorus) in a rapidly growing metropolitan area, the Las Vegas Valley, were studied to assess the contributions of point and nonpoint pollution sources under dry weather flow (pre rainfall) and wet weather flow (post rainfall) events. Nonpoint sources emanating from urban centers and septic seepage were found to be a primary source of bacterial contamination in the Las Vegas Wash, a mainstream wash channel where the Las Vegas Valley watershed drains. Contribution of point sources (wastewater treatment plants) to E. coli and total coliforms were found to be negligible. However, data in the Tropicana/Flamingo Wash, a tributary of the Las Vegas Wash, showed high bacterial activities in the wet antecedent rainfall condition as compared to the pre-rain dry antecedent condition suggesting that the rainfall increased bacterial activities.     

盐湖流域空-天-地立体监测系统结合VIC模型径流模拟初探

盐湖流域属于无资料地区且基础资料稀缺,使用传统方法开展水文模拟存在困难。为了研究盐湖流域生态环境、水文气象等变化,综合利用卫星遥感、无人船等技术,建立盐湖流域空-天-地立体监测系统,构建盐湖水位-面积-容积关系曲线,并通过月尺度遥感数据解译了盐湖月尺度湖泊面积,推算了盐湖蓄变量和盐湖入湖月尺度径流量。通过收集并整理中国区域地面气象要素驱动数据集CMFD和MODIS LAI叶面积指数等数据,构建了基于多源数据的VIC模型,开展盐湖流域湖泊径流模拟研究。结果表明,盐湖流域径流模拟纳什系数NSE和相对误差分别为0.87和11.81%,表现出实际径流的丰枯变化情况。盐湖流域空-天-地立体监测系统结合VIC模型能够模拟盐湖流域的月尺度径流变化过程,对无资料区域河湖水文模拟具有一定参考意义。