城市雨洪现状分析与收集利用

针对我国尤其是北方部分干旱缺水地区水资源的特点.分析了城市雨洪利用的紧迫性、发展概况、存在问题及应用前景,阐述了目前国内外雨洪资源化的理论与实践进展情况.结合我国实际情况,对雨洪资源利用今后的工作提出合理化建议.研究表明,城市雨洪利用不仅是开源节流的良策,也是改善生态环境、形成区域健康循环的有效措施.     

建筑与小区雨水调蓄设施的径流控制效果分析

近年来,内涝成为城市发展过程的一个突出问题,为减轻内涝灾害造成的损失,北京市颁发了《雨水控制与利用工程设计规范》(DB 11/685-2013),提出建筑与小区开发过程中应保证雨水调蓄设施容积、下凹式绿地比例、透水铺装使用率等3项指标,通过建立模型分析这些措施的雨洪控制利用效果。在此基础上,以北京市2011~2013年的实际降雨为例,研究了蓄水池和生态调蓄措施(以雨水花园为代表)在雨水径流控制效果方面的差异。     

Development of a distributed hydrological model based on urban databanks--production processes of URBS.

The objective of this study is to present a distributed hydrological model especially dedicated to urban catchments, and able to represent hydrological processes usually neglected in urban modelling, such as evapotranspiration, infiltration in roads, or direct infiltration of soil water in sewers. This model, called URBS (as Urban Runoff Branching Structure) is distributed considering the spatial variability of land use which is well known thanks to urban databanks managed by GIS. The production function is detailed at each cadastral parcel scale, and the runoff produced is routed by a simple transfer function. The estimation of the input parameters of the model is mostly based on physical considerations, and the model is applied on a suburban catchment in Nantes (France) in order to evaluate the interest of the distribution of the hydrological variables.     

The ecological value of constructed wetlands for treating urban runoff.

The Sweetwater Authority's urban runoff diversion system (URDS) comprises constructed wetlands on a hillside between the town of Spring Valley and the Sweetwater Reservoir, California, USA. The URDS were designed to divert dry-weather and first-flush urban runoff flows from the Sweetwater reservoir. However, these constructed wetlands have developed into ecologically valuable habitat. This paper evaluates the following ecological questions related to the URDS: (1) the natural development of the species present and their growth pattern; (2) the biodiversity and pollutant stress on the plants and invertebrates; and (3) the question of habitat provided for endangered species. The URDS wetlands are comprised primarily of rush (Scirpus spp.) and cattails (Typha spp.). This vegetative cover ranged from 39-78% of the area of the individual wetland ponds. Current analyses of plant tissues and wetland sediment indicates the importance of sediment sorption for metals and plant uptake of nutrients. Analyses of URDS water following runoff events show the URDS wetlands do reduce the amount of nutrients and metals in the water column. Invertebrate surveys of the wetland ponds revealed lower habitat quality and environmental stress compared to unpolluted natural habitat. The value of the wetlands as wildlife habitat is constrained by low plant biodiversity and pollution stress from the runoff. Since the primary Sweetwater Authority goal is to maintain good water quality for drinking, any secondary utilization of URDS habitat by species (endangered or otherwise) is deemed an added benefit.     

The hydrodynamic filter separator for removal of urban storm runoff.

The majority of storm runoff pollution is trapped in particles smaller than 100 microm in diameter. Solid particles smaller than 100 microm in diameter are not easily separated by conventional types of hydrodynamic separator, and remain in suspension in overflow. To overcome this problem, a HDFS (hydrodynamic filter separator) has been developed for treatment of the microparticles in urban storm runoff. We conducted a laboratory scale study on treatable potential of microparticles using HDFS that combined HDS with perlite filter. To determine the efficiency for various operation conditions, a series of experiments was performed with different solids concentrations and surface loading rate. The operation ranges of surface loading rates were 100 to 2,800 m3/m2/day, and influent solids concentrations were varied from 800 to 1,900 mg/L. Also, the particle size distribution was monitored to investigate the effects of surface loading rates on the particle size. Results indicated that the HDFS-inside type showed greater efficiency at solids separation than the other type.     

SSUIS - a research model for predicting suspended solids loads in stormwater runoff from urban impervious surfaces

Suspended solids from urban impervious surfaces (SSUIS) is a spreadsheet-based model that predicts the mass loading of suspended solids (SS) in stormwater runoff generated from impervious urban surfaces. The model is intended to be a research tool and incorporates several particle accumulation and washoff processes. Development of SSUIS is based on interpretation of storm event data obtained from a galvanised iron roof, a concrete car park and a bitumen road located in Toowoomba, Australia. SSUIS is a source area model that tracks the particle mass balance on the impervious surface and within its lateral drain to a point of discharge. Particles are separated into two groups: free and detained, depending on the rainfall energy required for surface washoff. Calibration and verification of SSUIS against the Toowoomba SS data yielded R(2) values ranging from 0.60 to 0.98. Parameter sensitivity analysis and an example of how SSUIS can be applied to predict the treatment efficiency of a grass swale are also provided.     

Multiple-event study of bioretention for treatment of urban storm water runoff.

Bioretention is a novel best management practice for urban storm water, employed to minimize the impact of urban runoff during storm events. Bioretention consists of porous media layers that can remove pollutants from infiltrating runoff via mechanisms that include adsorption, precipitation, and filtration. However, the effectiveness of bioretention in treating repetitive inputs of runoff has not been investigated. In this study, a bioretention test column was set up and experiments proceeded once every week for a total of 12 tests. Through all 12 repetitions, the infiltration rate remained constant (0.35 cm/min). All 12 tests demonstrated excellent removal efficiency for TSS, oil/grease, and lead (99%). For total phosphorus, the removal efficiency was about 47% the system removal efficiency ranged from 2.3% to 23%. Effluent nitrate concentration became higher than the influent concentration during the first 28 days and removal efficiency ranged from 9% to 20% afterward. Some degree of denitrification was apparently proceeding in the bioretention system. Overall, the top mulch layer filtered most of TSS in the runoff and prevented the bioretention media from clogging during 12 repetitions. Runoff quality was improved by the bioretention column.     

小流域产水产沙计算中地理信息的提取和分布式功能的实现

以栅格DEM为基础,以地理信息系统为平台,自动提取模型计算所需要的参数,基于COMGIS的ESRI ArcObjects平台,应用VBA进行二次开发,实现了水文模型和产沙模型以及模型与GIS的紧密耦合,最终实现了模型分布式功能.     

Surface models for coupled modelling of runoff and sewer flow in urban areas.

Traditional methods fail for the purpose of simulating the complete flow process in urban areas as a consequence of heavy rainfall and as required by the European Standard EN-752 since the bi-directional coupling between sewer and surface is not properly handled. The new methodology, developed in the EUREKA-project RisUrSim, solves this problem by carrying out the runoff on the basis of shallow water equations solved on high-resolution surface grids. Exchange nodes between the sewer and the surface, like inlets and manholes, are located in the computational grid and water leaving the sewer in case of surcharge is further distributed on the surface. Dense topographical information is needed to build a model suitable for hydrodynamic runoff calculations; in urban areas, in addition, many line-shaped elements like houses, curbs, etc. guide the runoff of water and require polygonal input. Airborne data collection methods offer a great chance to economically gather densely sampled input data.     

分布式侵蚀产沙模型在流域减水减沙效益评价中的应用

采用分布式侵蚀产沙模型,以陕西省黑草河小流域为例,对多种水土保持措施和不同土地利用方式条件下流域的径流输沙过程进行数值模拟计算,并通过对比评价了不同水土保持措施和土地利用方式的减水减沙效益,为流域内配置水土保持措施和优化流域管理提供了科学依据和技术支撑.     

Development of a horizontal subsurface flow modular constructed wetland for urban runoff treatment

Constructed wetlands (CWs) are well recognized as having low construction and maintenance cost and low energy requirement. However, CW design has been mainly based on rule-of-thumb approaches. In this study, the efficiency of a modular horizontal subsurface flow (HSSF) CW using four different design schemes was investigated. Based on the results, the four systems have attained more than 90% removal of total suspended solids and more than 50% removal efficiency for total phosphorus, PO(4)-P and Zn. The planted system achieved higher pollutant removal rates than the unplanted system. In terms of media, bottom ash was more effective than woodchip in reducing the pollutants. Considering the flow length, optimum removal efficiency was achieved after passing the sedimentation tank and vertical media layer; with respect to depth, more pollutants were removed in the upper sand layer than in the lower gravel layer. This study recommended a surface area of 0.25 to 0.8% of catchment area for planted CW and 0.26 to 0.9% for unplanted CW using the 7.5 to 10 mm design rainfall.     

Application of mulch for treating metals in urban runoff: batch and column test.

Among the many methods available for the removal of heavy metals in urban nonpoint source pollution (NSP), adsorption has been shown to be an economically feasible alternative. To adsorb the amount of heavy metals in runoff, filtration of runoff through a specially constructed filter system is one possible treatment method. The mulch layer in a specially constructed filter system functions through adsorptive-filtration, where some pollutants are immobilised through sorption and some pollutants associated with suspended solids are immobilised through filtration. Therefore, the major interest of this study was to investigate the possibility of utilising mulch for the adsorption of heavy metals such as cadmium, copper, lead and zinc for a solution typical of those found in urban runoff using the flask-type adsorption batch tests and laboratory column tests. From the equilibrium sorption batch tests, it was observed that the adsorption of heavy metals on mulch with the same initial concentrations of metals in the solution decreased in the order Pb(II) > Cu(II) > Zn(II) > Cd(II) regardless of changes in pH. In column tests, the breakthrough curves for various heavy metals' adsorption by mulch showed that the binding strength of the following metal ions onto mulch was as follows: Pb(II) > Cu(II) > Zn(II) > Cd(II).     

Metal concentrations in soil and seepage water due to infiltration of roof runoff by long term numerical modelling.

The qualitative effects of stormwater infiltration on soil and seepage water are investigated with long term numerical modelling. The retention behaviour of different soils and materials used in infiltration devices is determined with batch and column tests. Results of the laboratory tests are adsorption isotherms which represent input data for numerical transport modelling. The long term simulations are performed with combinations of different solutions (types of roof runoff) and infiltration devices (swale and trench) under different hydrogeological conditions. The presented results contain the infiltration of low polluted roof runoff, runoff from a roof with zinc sheets and from a roof with copper sheets concerning the heavy metals zinc, copper and lead. The increase of concentrations in the infiltration body is high. For the infiltrated water, the results show a migration to groundwater only for the low adsorbing soil.     

The characteristics and measuring technique of refractory dissolved organic substances in urban runoff.

It is considered that refractory dissolved organic substances have caused an increase in the COD concentration in Lake Biwa in recent years. We investigated the organic matter in the first flush of stormwater runoff from a road in the watershed area of the lake, and studied the possibility of improvement in the water environment from that aspect. After percolating the stormwater through soil, we analyzed organic substances fractionated by using GPC-TC. And we examined the effect of removal of organic substances by comparing the peak height before and after percolation. In the result of the experiments, we found that soil infiltration reduced the refractory dissolved organic substance and we successfully designed a system for a simple and easy experimental facility to treat urban runoff.     

Prolonged deposition of heavy metals in infiltration facilities and its possible threat to groundwater contamination.

A field investigation of infiltration facilities, built two decades ago in Tokyo, was carried out and sediment samples were collected from 12 infiltration inlets of three different locations. Heavy metals contents in the inlet sediment, road dusts and soils samples were analysed and compared. The particle size distribution analysis showed its variation in depth as well as from inlet to inlet. The nature of organic substances present in sediment found changes in particle sizes as well as in depth. The heavy metals content in the sediment samples ranged from 6-143 (Cr), 1-84 (Ni), 49-331 (Cu), 210-2186 (Zn) and 2-332 (Pb) microg/g. The heavy metal content ranges were similar to road dust, which indicated road dust as a possible source for sediment for the infiltration inlets. The lower heavy metals content in many sediment samples than the soil indicated possible release/desorption of heavy metals under newly created environments such as an anaerobic environment. Among the heavy metals there was a relatively good relationship between Cu and Zn, indicating the existence of their common sources.     

Effect of uncertainties in agricultural working schedules and Monte-Carlo evaluation of the model input in basin-scale runoff model analysis of herbicides.

In the prediction of time-series concentrations of herbicides in river water with diffuse-pollution hydrological models, farming schedules (the dates of herbicide application and drainage of irrigation water from rice paddies) greatly affect the runoff behavior of the herbicides. For large catchments, obtaining precise data on farming schedules is impractical, and so the model input inevitably includes substantial uncertainty. This paper evaluates the effectiveness of using the Monte-Carlo method to generate sets of estimated farming schedules to use as input to a GIS-based basin-scale runoff model to predict the concentrations of paddy-farming herbicides in river water. The effects of using the Monte-Carlo method to compensate for uncertainty in the evaluated parameters for herbicide decomposition and sorption were also evaluated.     

城市雨水利用的基本形式与效益分析方法

通过5种类型总面积60ha的6个雨水利用示范区的建设,和近5年的试验观测,研究总结了城市雨水利用的基本形式,即入渗地下、收集回用和调控排放,并探讨了实施城市雨水利用的经济效益、环境和社会效益分析方法。分析结果表明,城市雨水利用的社会性效益远大于小区建设者或业主的直接经济效益,需要政府通过政策刺激和鼓励小区建设者或业主投资建设雨水利用工程。     

A new database on urban runoff pollution: comparison of separate and combined sewer systems.

For a long time people have questioned what the "best" sewer system is for limiting the pollution load released into the receiving waters. In this paper the traditional separate and combined sewer systems are compared using a pollution load balance. The investigation is based on measured concentration data for a range of pollutant parameters in the sewer from the new database "ATV-DVWK Datenpool 2001". The approach also accounted for the wastewater treatment plant outflow which contributes to the total pollutant load considerably. In spite of a number of neglected effects, the results show that the separate system is superior to the combined for some parameters only, such as nutrients, whereas for other parameters, e.g. heavy metals and COD, the combined system yields less total loads. Any uncritical preference of the separate system as a particularly advantageous solution is thus questionable. Individual investigations case by case are recommended.     

城市雨洪模型在天津市区排水分析计算中的应用

针对天津市城区产汇流特性 ,在充分论证和经过验区检验的基础上 ,引进美国雨洪管理模型 (SWMW) ,详细地进行了市区二级河道的排涝模拟与计算 ,并计算出市区有关控制断面的出流过程