Characteristics of litter waste in highway storm runoff.

Litter characterization is an integrated part of the Caltrans First Flush Characterization Study. These data will provide a basis to develop potential treatment technologies and best management practices to control pollutants in runoff from freeways. During monitoring periods in Southern California areas, the first flush phenomenon was evaluated and the impacts of various parameters such as rain intensity, drainage area, peak flow rate, and antecedent dry period on litter volume and loading rates were evaluated. First flush phenomenon was generally observed for litter concentrations, but was not apparent with litter mass loading rates. Total captured gross pollutants, defined as larger than 0.5 cm, was 90% vegetation with only 10% being litter. The normalized cumulative litter loadings were determined from 1.25 to 13.39 kg/ha for dry litter weight and 0.40 to 8.99 kg/ha for dry biodegradable litter weight. The portions of biodegradable litter to non-biodegradable litter were roughly the same across the entire event. Event mean concentrations were ranged 0.0021 to 0.259 g/L for wet gross pollutants, 0.0001 to 0.027 g/L for wet litters and 0.00007 to 0.018 g/L for dry litters. The mass emission rates should be useful to estimate total litter production for developing total maximum daily loads.     

Leaching of additives from construction materials to urban storm water runoff

Urban water management requires further clarification about pollutants in storm water. Little is known about the release of organic additives used in construction materials and the impact of these compounds to storm water runoff. We investigated sources and pathways of additives used in construction materials, i.e., biocides in facades' render as well as root protection products in bitumen membranes for rooftops. Under wet-weather conditions, the concentrations of diuron, terbutryn, carbendazim, irgarol 1051 (all from facades) and mecoprop in storm water and receiving water exceeded the predicted no-effect concentrations values and the Swiss water quality standard of 0.1 microg/L. Under laboratory conditions maximum concentrations of additives were in the range of a few milligrams and a few hundred micrograms per litre in runoff of facades and bitumen membranes. Runoff from aged materials shows approximately one to two orders of magnitude lower concentrations. Concentrations decreased also during individual runoff events. In storm water and receiving water the occurrence of additives did not follow the typical first flush model. This can be explained by the release lasting over the time of rainfall and the complexity of the drainage network. Beside the amounts used, the impact of construction materials containing hazardous additives on water quality is related clearly to the age of the buildings and the separated sewer network. The development of improved products regarding release of hazardous additives is the most efficient way of reducing the pollutant load from construction materials in storm water runoff.     

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.     

Aggregated runoff from small watersheds based on stochastic representation of storm events

This paper is concerned with the estimation of aggregated direct runoff from small watersheds during a time interval (0,t), homogeneous with respect to rainfall characteristics. The storm events are simulated by a Poisson process, whereas direct runoff is estimated by the SCS method or a linear regression model. The probability of the occurrence of direct runoff is incorporated in the proposed method by examining the possibility of each storm exceeding the watershed losses index. A closed form solution is derived for the expected total direct runoff in the interval (0,t). Finally, the proposed method is applied to a particular set of conditions.Notation Q direct runoff - P rainfall depth - S index of watershed storage - CN Curve Number of SCS method - t time - T _i time interval between successive storm events (i andi+1) - X _i storm depth of theith event (case a) excess storm depth of theith event (case b) - Y(t) total direct runoff in (0,t) - N(t) number of storm events in (0,t) - F(t) distribution function of the time between storm events - G(x) distribution function of the storm depth - F _n(t),F _n+1(t) n-fold and (n+1)-fold convolution ofF(t), respectively - G _n(x),G _n+1(x) n-fold and (n+1)-fold convolution ofG(x), respectively - E[X] expected mean value - p probability of exceeding the thresholde,p+q=1 - * convolution operation     

平原城市雨洪过程模拟

本文提出一个适合平原城市水文过程模拟的数学模型，由产流、坡面汇流、管网汇流、河网汇流4个子模型组成.对北京市太平湖排水小区雨洪过程模拟验证表明，结果是可靠和合理的.     

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.     

Long-term fluctuation and regional variation of nutrient loads from the atmosphere to lakes.

The atmospheric depositions were collected by ordinary bulk-samplers mounted with a glass or polyethylene funnel of 30 cm orifice. A long-term observation was carried out at a site (35 degrees 01'30"N, 135 degrees 58'07"E) in the urbanized area for 21 years since 1974. The annual volume-weighted average concentrations of total nitrogen (TN) and phosphorus (TP) were 1.02 +/- 0.30 and 0.031 +/- 0.015 mg(-1), respectively, and the loading rates were 14.5 +/- 2.8 and 0.43 +/- 0.16 kg ha(-1) yr(-1). The rates neither had a relationship with the precipitation (1,492 +/- 343 mm yr(-1)) nor showed any diachronic tendencies. In order to obtain the loading rate of TN and TP within 10% uncertainty under the significant level of 0.01, there is no way but to continue the observation for seven and eleven years or more, respectively. In order to clarify the regional variation of the loading amounts of the depositions, the samplers were set at 12 sites distributing throughout the Kinki District for two years. The distance from northernmost (2322 mm yr(-1)) to southernmost (1242 mm yr(-1)) is about 150 km. The average loading rates of the 12 sites were 16.2 +/- 2.5 kg ha(-1) yr(-1) of TN and 0.730 +/- 0.247 kg ha(-1) yr(-1) of TP. The depositions of NO3-N, NH4-N, and TN as well as TP showed tendencies with distances neither from a big city nor from Japan Sea.     

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.     

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.     

Integration of aspect and slope in snowmelt runoff modeling in a mountain watershed

This study assessed the performances of the traditional temperature-index snowmelt runoff model(SRM) and an SRM model with a finer zonation based on aspect and slope(SRM + AS model) in a data-scarce mountain watershed in the Urumqi River Basin,in Northwest China.The proposed SRM + AS model was used to estimate the melt rate with the degree-day factor(DDF) through the division of watershed elevation zones based on aspect and slope.The simulation results of the SRM + AS model were compared with those of the traditional SRM model to identify the improvements of the SRM + AS model's performance with consideration of topographic features of the watershed.The results show that the performance of the SRM + AS model has improved slightly compared to that of the SRM model.The coefficients of determination increased from 0.73,0.69,and 0.79 with the SRM model to 0.76,0.76,and 0.81 with the SRM + AS model during the simulation and validation periods in 2005,2006,and 2007,respectively.The proposed SRM + AS model that considers aspect and slope can improve the accuracy of snowmelt runoff simulation compared to the traditional SRM model in mountain watersheds in arid regions by proper parameterization,careful input data selection,and data preparation.     

新安江模型产流模式在山区型和平原型水库入库径流量中的模拟与应用

将新安江模型的蓄满产流模式应用于浙江省台州市山区型和平原型两个水库的入库径流量模拟之中,取得较好的效果。分析了山区型和平原型水库径流模型参数的取值规律,为台州市其他无资料地区的模型参数取值提供参考,为下一步该区域的水量水质耦合的水资源配置提供研究基础。     

Study of water quality distribution in Lake Biwa in consideration of runoff pollutant loads from its catchment basin.

Many strategies for water quality conservation in Lake Biwa are being carried out mainly by reducing runoff pollutant loads into the lake. But influence of the runoff load reduction on the water quality in Lake Biwa has not been clarified enough so far. This study is aimed at discussing methodology to estimate water quality distribution in Lake Biwa using runoff pollutant loads from its basin. The runoff loads from the basin are calculated by Macro Model with GIS database of the Lake Biwa basin, and the water quality distribution in the lake is estimated by the spline technique with the calculated runoff loads. As a result, it has been proved that the methodology has enough reproducibility to estimate the water quality distribution in Lake Biwa and is available to examine the water quality in the lake.     

Characteristics of storm runoff and sediment dispersal in the San Pedro Channel, southern California.

In-site measurements of particle size spectra were obtained from three offshore cruises to evaluate the physical consequences of increased sediment transport and deposition offshore which was caused by episodic storm runoff water from the Santa Ana River watershed, a highly urbanised coastal watershed in southern California. Of the total annual runoff discharge to the coastal ocean, 89.2% occurred in the 2003/2004 winter season, and 0.22 Mt of sediment mass was transported during the storm events. The runoff plume at surface taken offshore by cross-shore currents progressed rapid aggregation and sedimentation, while the initially high concentration of suspended sediment discharged from the river outlet was dominated by small particles. Vertical profiles of particle size spectra revealed two separated plumes near the river outlet and turbidity plume along the bottom consisted of an abundance of very fine and dense particles. It would appear to support the theory that even if the storm runoff does not carry a high concentration of sediment being capable of generating negative buoyancy, sediment deposition on the shelf might mobilise in dense, fluid mud transported offshore by gravity. In a coastal pollution context, sediment particle size spectra information may offer potentially useful means of characterising particle-associated pollutants for purposes of source tracking and environmental interpretation.     

北京地区主要河流水沙量变化分析

河流水沙量是水利工程和各类涉水基础设施建设中需要考虑的重要要素，其大小和变化对于水资源开发利用及河道治理等意义重大。通过收集北京地区主要河流13个水文站自开展水沙实测(或1950年)至2022年的年径流量和年输沙量数据，系统分析各站的水沙变化过程及趋势，研究表明，北京地区主要河流的水沙量年内分布不均，年际变幅大，水沙变化基本同步。几乎所有河流的年径流量和年输沙量均呈下降趋势且2000年后水沙量锐减。潮白河水系干支流的下堡站、张家坟站、下会站、前辛庄站和口头站2001—2022年的年径流量均值约为多年均值的1/2，2001—2022年的年输沙量均值为多年均值的2%~19%，苏庄站2000年之后大多数年份河干断流;永定河水系雁翅站2001—2022年的年径流量均值为多年均值的30%，2001—2022年的年输沙量均值接近0;三家店站和卢沟桥站2000年后大多数年份的年径流量和年输沙量为0。大清河水系漫水河站和张坊站2001—2022年的年径流量均值约为多年均值的20%，2000年后漫水河站大多数年份年输沙量为0，张坊站2001—2022年的年输沙量均值为多年均值的17%。河流水沙量大幅降低的主要驱动因素是受人类活动的影响，主要包括上游库坝拦截、塘坝和灌区增加、小流域治理和水土保持工作的成效等。气候变化引起年降水量(特别是汛期降水量)的减少对河流水沙量有一定的影响。     

北京长河湾流域径流非点源污染总量估算

针对北京城区流域径流非点源污染问题,选择典型流域--长河湾作为研究对象,采用源类型方法对汇入该流域的雨水水质进行分析,估算单场降雨径流的污染负荷,从而推算出流域的年径流污染负荷总量,并建立了径流污染主要水质指标之间的量化关系.结果表明,道路及屋面径流雨水中主要污染物(CODer、SS、TN、TP)之间存在良好的相关性;长河湾流域的径流非点源年污染负荷总量巨大,对城区水系构成了严重威胁.     

研究湿地有效面积对暴雨径流调控作用的多因子模型

根据湿地系统水量平衡及植物生长的需求，考虑了流域的降雨量、湿地土壤下渗量、降雨时间间隔、水面蒸发量、植物蒸腾量、排水量等主要的水文因素，推导出具有广泛意义的人工湿地面积/降雨径流截留率模型。模型的参数确定简单，应用方便。我们以巢湖边的六岔河小流域为例模拟了在不同降雨过程、截留率和降雨时间间隔的湿地面积变化，并且与实测数据进行对比。结果表明，模型与实测物吻合较好。     

Evaluation of three unit hydrograph models to predict the surface runoff from a Canadian watershed

The predictability of unit hydrograph (UH) models that are based on the concepts of land morphology and isochrones to generate direct runoff hydrograph (DRH) were evaluated in this paper. The intention of this study was to evaluate the models for accurate runoff prediction from ungauged watershed using the ArcGIS^® tool. Three models such as exponential distributed geomorphologic instantaneous unit hydrograph (ED-GIUH) model, GIUH based Clark model, and spatially distributed unit hydrograph (SDUH) model, were used to generate the DRHs for the St. Esprit watershed, Quebec, Canada. Predictability of these models was evaluated by comparing the generated DRHs versus the observed DRH at the watershed outlet. The model input data, including natural drainage network and Horton's morphological parameters (e.g. isochrone and instantaneous unit hydrograph), were prepared using a watershed morphological estimation tool (WMET) on ArcGIS^® platform. The isochrone feature class was generated in ArcGIS^® using the time of concentration concepts for overland and channel flow and the instantaneous unit hydrograph was generated using the Clark's reservoir routing and S-hydrograph methods. An accounting procedure was used to estimate UH and DRHs from rainfall events of the watershed. The variable slope method and phi-index method were used for base flow separation and rainfall excess estimation, respectively. It was revealed that the ED-GIUH models performed better for prediction of DRHs for short duration (≤6 h) storm events more accurately (prediction error as low as 4.6–22.8%) for the study watershed, than the GIUH and SDUH models. Thus, facilitated by using ArcGIS^®, the ED-GIUH model could be used as a potential tool to predict DRHs for ungauged watersheds that have similar geomorphology as that of the St. Esprit watershed.     

SWMM模型模拟雨洪原理剖析及应用建议

通过对SWMM模型结构和参数的剖析,证明其对城市雨洪形成过程的描述是符合迄今为止人们对城市产汇流规律的认知的。采用的产流分析方法以水文学为基础,汇流分析方法以水力学为基础,其物理概念清晰。包含的参数大多具有几何意义或物理意义,但有些参数之间存在互补性或相依性,这就要求在率定这些参数时应设法减少"异参同效"的影响。汇水区出口的雨洪过程的复合采用同时刻叠加的方法,表明来自不同部分洪水的相互干扰是被忽略的。     

How uncertain is model-based prediction of copper loads in stormwater runoff?

In this paper, we conduct a systematic analysis of the uncertainty related with estimating the total load of pollution (copper) from a separate stormwater drainage system, conditioned on a specific combination of input data, a dynamic conceptual pollutant accumulation-washout model and measurements (runoff volumes and pollutant masses). We use the generalized likelihood uncertainty estimation (GLUE) methodology and generate posterior parameter distributions that result in model outputs encompassing a significant number of the highly variable measurements. Given the applied pollution accumulation-washout model and a total of 57 measurements during one month, the total predicted copper masses can be predicted within a range of +/-50% of the median value. The message is that this relatively large uncertainty should be acknowledged in connection with posting statements about micropollutant loads as estimated from dynamic models, even when calibrated with on-site concentration data.