利用DRAINMOD模型模拟水田旱地排水径流过程

为了掌握水稻田在调洪滞涝中的作用及其影响因素,以湖北省汉川市的洪西垸径流区为例,分析了水田旱地的排水径流特点,利用DRAINMOD模型对水田旱地的排水径流过程进行了模拟分析。结果表明,模拟的排水径流量与实测值吻合较好,且旱地的模拟效果优于水田;在汛期即水田旱地作物生长期内,水田区的排水径流量小于旱地区,水稻田可较好地起到拦蓄径流的作用。

排水径流模拟系统及其应用

本系统是从不稳定流的基本微分方程出发,用差分解法求解的排水径流模拟系统,重通过黑龙江省科委鉴定.

茭白叶还田对茭田径流排水水质的影响

采用茭白田野外田间试验,研究了茭白叶还田与移除不还田对径流排水水质的影响。研究表明,茭白叶还田处理径流水中铵态氮、总磷和化学需氧量(COD)等浓度均超过国家Ⅴ类地表水体的标准;茭白叶移除不还田处理,在双季茭白田中径流水铵态氮、总磷和COD浓度降低17.2%、14.2%和3.8%,单季茭白田中降低84.6%、45.1%和26.1%。采用茭白叶移除不还田措施,可降低种植排水中铵态氮、总磷、COD的含量,有效减轻茭白田产生的面源污染风险。

环山引水渠区间径流引排水处理办法分析

吴厝水电站西源引水渠溢流渠的建设标准低、引水能力弱,渠道经常受塌方堵塞、淤积、渗漏等的影响。根据溢流渠现状的损坏程度、溢流渠的坡度、挡墙破损等情况,结合工程设计要求,通过改建引水渠溢流渠段、新建急流槽、新建混凝土护面等,实现引水流量3.5~5.5 m^(3)/s和年均可引水量3374.6万m3的目标。通过制定急流槽施工方案,优化施工步骤和改善施工条件,分析干渠区间来水和引水现状,以及干渠区间排洪和泄沙设施运行状况,以优化整个施工过程、提升整体施工效率,降低项目施工成本。

Pollution control of outfall of rainwater-sewage confluence in old town

In order to improve water quality of middle ancient canal in Zhenjiang city a pollution control project was carried out.The research area is the middle catchment area of the ancient canal river system in the old town of Zhenjiang. The specific research object is the runoff of the outfall of rainwater-sewage confluence in the area. On the basis of detecting and analyzing the water yield and water quality of the runoff of rainwater-sewage confluence a combined technology which contains four independent continuous processes for lowering pollution load was developed and system equipment was established and put into operation. The processing effects of the project were monitored and analyzed.The results show that the pollution control project of outfall runoff is efficient which decreases the pollution load including chemical oxygen demand COD total phosphorus TP suspended solids SS and ammonia-nitrogen NH3-N .As a result the water environment of the ancient canal is protected.

Characterization of suspended solids and particle-bound heavy metals in a first flush of highway runoff

To investigate the dynamic characteristics of total suspended solids (TSS) and their particle-bound heavy metals in a first flush, the runoff sampling together with its flow rate measuring was conducted for three rainfall events at outfalls of highway in Shanghai from June to September 2007. Field samples were analyzed to determine the concentrations of TSS and particle-bound heavy metals, such as Zn, Pb, and Cu. Results show that the wash off behavior of TSS under varying runoff rate condition can be explained by different antecedent dry weather period (ADWP). Contribution of fine fraction (<45 μm) to TSS was generally higher than that of coarse fraction (>45 μm). When the runoff flow increased obviously, a significant contribution of the coarse fraction was observed for a certain rainfall events with long antecedent dry weather condition. The changes of total metals concentration and particle-bound metal concentrations were strongly dependent on the TSS variation. TSS was generally well correlated with most particulate-bound heavy metals. Of the heavy metals, the concentration of Zn was found considerably high and that of Pb was significantly low at North Zhongshan 2 Road, in Shanghai, China, but they are still within the range reported in the literature. Fluctuation of heavy metal contents in the coarse fraction during a first flush period was more significant compared with that in the fine fraction. The results will assist in the development of effective control strategies to minimize heavy metals and solids in highway runoff.

Responses of Hydrological Processes to Climate Change in the Zhujiang River Basin in the 21st Century

In this study, discharge at the outlet of Xijiang River, the biggest sub-basin of the Zhujiang River, was simulated and projected from 1961 to 2099 using the hydrological model HBV-D. The model uses precipitation and temperature data from CISRO/MK3 5, MPI/ECHAM5, and NCAR/CCSM3 under three greenhouse gas emission scenarios (SRES A2, A1B, B1). The results in water resources and flood frequency suggest that annual precipitation and annual runoff would increase after 2050 relative to the reference period of 1961-1990. In addition, increasing trends have been projected in area averaged monthly precipitation and runoff from May to October, while decreasing trends in those from December to February. More often and larger floods would occur in future. Potential increase in runoff during the low-flow season could ease the pressure of water demand until 2030, but the increase in runoff in the high-flow season, with more often and larger floods, more pressure on flood control after 2050 is expected.

Effect of Drainage Ditch Layout on Nitrogen Loss by Runoff from an Agricultural Watershed

A comparison experiment was performed, by designing one field ditch （D1 treatment）, two field ditches （D2 treatment）, three field ditches （D3 treatment）, and no field ditch （CK treatment）, in an upland of a small agricultural watershed in Nanjing-Zhenjiang hilly regions to observe the farmland surface runoff and N loss characteristics under the different layouts of field ditch. As the layout density of field ditch increased, the drainage effect was improved, the timing of the runoff peak was advanced, and also the peak flow was augmented. At the same time, both the concentration and accumulated transfer flux of total nitrogen （TN） were improved, and thereinto the accumulated transfer fluxes of TN under D3, D2 and D1 treatments were increased by 1.46, 1.34 and 1.16 times, respectively, than that under CK treatment. However, the accumulated transfer fluxes of nitrate-nitrogen （NO3-N） and ammonium-nitrogen （NH4＋-N） under D3, D2 and D1 treatments were reduced by 33.9%, 21.4% and 8.6%, and 35.8%, 24.7% and 12.2%, respectively, compared with those under CK treatment. Under CK treatment, the NO3-N and NH4＋-N concentrations were more sensitive to rainfall intensity than the TN concentration. There were significant linear relationships between the transfer fluxes of TN, NO3-N and NH^-N and the runoff flux, with the correlation coefficients of 0.942, 0.899 and 0.912, respectively. In addition, this correlation was also influenced by the layout density of field ditch. Therefore, the environmental effect should be taken into account when designing and constructing field ditches. Especially in the regions of severe fertilizer loss, the approaches of properly increasing the drainage area and decreasing the layout density of field ditch could be adopted under the precondition of avoiding crops from waterlogging.