秦皇岛沿海灾害性天气对自然环境的影响和预报

风暴潮天气是一种灾害性的自然现象。一般情况下,大于500 km的东到东北大风持续12个小时,且风速大于或等于6级,将在秦皇岛沿海形成风暴潮天气。通过分析引发风暴潮天气的动力条件,风暴潮与台风、温带气旋等天气系统相关联系,再根据天文、潮汐变化、台风、温带气旋24 h诊断预报,判断台风、温带气旋移动径,从而达到准确预报风暴潮天气之目的。分析表明:成灾风暴潮多发生在朔日和望日及其后的5天。     

Simulated interior floods and the flood experience in urban communities

The Hydrologic Engineering Center (HEC-1) model was used to construct synthetic hydrographs for isolated interior urban floods. Flood peak and lag time were very well preserved in simulated flows. Total volume was not adequately expressed. Lag time varied inversely with both urban development and storm intensity. Peak discharge varied with storm intensity, but this variability was well defined only at very high urbanization levels. An 175% increase in storm intensity produced a change of about 15% in peak discharge. Claims for flood damage correlated well with estimates of peak flow and lag time combined. Other measures of flood experience also correlated with the two features. Within the range of storms utilized, urban development factors consistently outranked storm intensity as a determining factor in flood damage.     

Management of Urban Road Runoff Containing PAHs: Probabilistic Modeling and Its Application in Beijing,China1

Abstract: Pollutant loading from storm runoff is considered to be an important component of nonpoint source pollution in urban areas. In developing countries, because of the accelerated urbanization and motorization, storm runoff pollution has become a challenge for improving aquatic environmental quality. An effective storm runoff management plan needs to be developed, and questions concerning how much and which proportion of a storm should be treated need to be answered. In this study, a model is developed to determine the fraction of storm runoff that needs to be treated to meet the discharge standard within a given probability. The model considers that the pollutants can be mobilized during the early stage of a storm. The model is applied to a field study of polycyclic aromatic hydrocarbons (PAHs) in road runoff in Beijing, China. In this case, the probability that the PAH load will be mobilized with suspended sediments by the earlier portion of the flush is 73%. Given the high PAH loading in the study area and the referenced discharge standard, the probability that the entire runoff should be captured and treated is 94%. Thus, urban planners need to consider treatment systems for the majority of the storms in this area, whether the PAH load is in the first flush or not. This methodology can be applied to other regions where PAH loads may result in different management outcomes.     

ROLE OF BASEFLOW IN RAINFALL-RUNOFF RELATIONS1

ABSTRACT. The role of initial baseflow, or the baseflow at the beginning of storm precipitation, in modifying mathematical rainfall-runoff relations is analyzed by using data from 95 storms over a drainage basin in Illinois. A regression model is set up with total runoff, surface runoff, baseflow runoff, and peak flow as dependent variables, and storm precipitation, initial baseflow, effective and total storm durations, and highest and lowest temperatures during the storm as independent variables. Stepwise regression analyses show that storm precipitation and initial baseflow are the most important variables for making dependent variable estimates. The standard error estimates using only storm precipitation and initial baseflow as predictors show a seasonal trend with a peak in July, August, or September. An understanding of the role of baseflow as an indicator of average soil moisture condition over the basin can be of great help in short-term reservoir regulation and flood warning.     

新疆45年间不同强度等级沙尘暴天气空间格局年际变化趋势研究

通过对1960-2005年新疆54个气象站的气象资料进行分析,研究了新疆不同强度等级沙尘暴天气的时空分布年际演变趋势.结果显示：新疆各强度等级沙尘暴天气的发生区域均在逐年缩小,强沙尘暴、扬沙发生区域有东移的趋势,浮尘空间分布格局显现出向南退缩的趋势.沙尘暴空间格局变动较频繁没有明显的移动趋势.     

STORM DISCHARGE,LOADS, AND AVERAGE CONCENTRATIONS IN NORTHWEST OHIO RIVERS, 1975–19951

ABSTRACT: A computerized technique was developed to identify storm runoff episodes and calculate storm discharges, storm loads, and storm average concentrations for each event in datasets with up to 10,000 records. This technique was applied to four watersheds within the Lake Erie drainage basin and identified between 160 and 250 runoff events in each. Storm event loads and storm event mean concentrations were calculated for each runoff event for suspended solids, total phosphorus, soluble reactive phosphorus, nitrate, and total Kjeldahl nitrogen. The basic characteristics of the resulting data are described, as are systematic differences as a function of watershed size, seasonal differences, and trends over time. Many of the results of this study reflect the importance of nonpoint processes and improvements in agricultural best management practices in these watersheds.     

CALIBRATION OF STORM LOADS IN THE SOUTH PRONG WATERSHED,FLORIDA, USING BASINS/HSPF1

ABSTRACT: The South Prong watershed is a major tributary system of the Sebastian River and adjacent Indian River Lagoon. Continued urbanization of the Sebastian River drainage basin and other watersheds of the Indian River Lagoon is expected to increase runoff and nonpoint source pollutant loads. The St. Johns River Water Management District developed watershed simulation models to estimate potential impacts on the ecological systems of receiving waters and to assist planners in devising strategies to prevent further degradation of water resources. In the South Prong system, a storm water sampling program was carried out to calibrate the water quality components of the watershed model for total suspended solids (TSS), total phosphorous (TP), and total nitrogen (TN). During the period of May to November 1999, water quality and flow data were collected at three locations within the watershed. Two of the sampling stations were located at the downstream end of major watercourses. The third station was located at the watershed outlet. Five storm events were sampled and measured at each station. Sampling was conducted at appropriate intervals to represent the rising limb, peak, and recession limb of each storm event. The simulations were handled by HSPF (Hydrologic Simulation Program‐Fortran). Results include calibration of the hydrology and calibration of the individual storm loads. The hydrologic calibration was continuous over the period 1994 through 1999. Simulated storm runoff, storm loads, and event mean concentrations were compared with their corresponding observed values. The hydrologic calibration showed good results. The outcome of the individual storm calibrations was mixed. Overall, however, the simulated storm loads agreed reasonably well with measured loads for a majority of the storms.     

成都市某区暴雨径流过程模拟分析

为提高城市雨洪管理的效率,最大限度地减少暴雨洪水带来的危害,针对城市防洪排涝的需要,在分析成都市某区降雨径流规律后,建立了该区暴雨径流模拟的数学模型,有助于采取相应措施充分利用雨洪资源。通过对雨洪过程模拟验证表明,模型适合该区域的实际情况,具有一定的合理性和可靠性。     

Differences in Dissolved Organic Carbon and Nitrogen Responses to Storm‐Event and Ground‐Water Conditions in a Forested,Glaciated Watershed in Western New York1

Abstract: Differences in the storm‐event responses of dissolved organic carbon (DOC) and nitrogen (DON) in streamflow and ground water were evaluated for a glaciated forested watershed in western New York. Eight to ten storm events with varying rainfall amounts, intensities, and antecedent moisture conditions were studied for three catchments (1.6, 3.4, and 696 ha) over a three‐year period (2003‐2005). Concentrations of DOC in streamflow exiting the catchments were significantly higher for storm events following a dry period, whereas no similar response was observed for DON. Highest DON concentrations in streamflow were typically associated with storm events following wet antecedent moisture conditions. In addition to antecedent moisture conditions, DOC concentrations were also positively correlated with precipitation amounts, while DON did not reveal a consistent pattern. Streamwater and ground‐water concentrations of DOC during storm events were also strongly correlated with riparian ground‐water depths but a similar relationship was not observed for DON. Ground‐water DON concentrations were also more variable than DOC. We hypothesized that the differences in DOC and DON responses stemmed from the differences in catchment sources of these solutes. This study suggests that while DOC and DON are intrinsically linked as components of dissolved organic matter, their dynamics and exports from watersheds may be regulated by a different set of mechanisms and factors. Identifying these differences is critical for developing more reliable and robust models for transport of dissolved organic matter.     

HYDROLOGIC IMPACTS OF ALTERNATIVE APPROACHES TO STORM WATER MANAGEMENT AND LAND DEVELOPMENT1

Low impact development (LID) and other land development methods have been presented as alternatives to conventional storm water management and site design. Low impact development encourages land preservation and use of distributed, infiltration‐based storm water management systems to minimize impacts on hydrology. Such systems can include shallow retention areas, akin to natural depression storage. Other approaches to land development may emphasize land preservation only. Herein, an analysis of four development alternatives is presented. The first was Traditional development with conventional pipe/pond storm water management and half‐acre lots. The second alternative was Cluster development, in which implementation of the local cluster development ordnance was assumed, resulting in quarter‐acre lots with a pipe/pond storm water management system and open space preservation. The “Partial” LID option used the same lot layout as the Traditional option, with a storm water management system emphasizing shallow depression storage. The “Full” LID used the Cluster site plan and the depression storage‐based storm water management system. The alternatives were compared to the hydrologic response of existing site conditions. The analysis used two design storms and a continuous rainfall record. The combination of land preservation and infiltration‐based storm water management yielded the hydrologic response closest to existing conditions, although ponds were required to control peak flows for the design storms.     

Effects of Impervious Area and BMP Implementation and Design on Storm Runoff and Water Quality in Eight Small Watersheds

The effects of increases in effective impervious area (EIA) and the implementation of water quality protection designed detention pond best management practices (BMPs) on storm runoff and stormwater quality were assessed in Gwinnett County, Georgia, for the period 2001‐2008. Trends among eight small watersheds were compared, using a time trend study design. Significant trends were detected in three storm hydrologic metrics and in five water quality constituents that were adjusted for variability in storm characteristics and climate. Trends in EIA ranged from 0.10 to 1.35, and changes in EIA treated by BMPs ranged from 0.19 to 1.32; both expressed in units of percentage of drainage area per year. Trend relations indicated that for every 1% increase in watershed EIA, about 2.6, 1.1, and 1.5% increases in EIA treated by BMPs would be required to counteract the effects of EIA added to the watersheds on peak streamflow, stormwater yield, and storm streamflow runoff, respectively. Relations between trends in EIA, BMP implementation, and water quality were counterintuitive. This may be the result of (1) changes in constituent inputs in the watersheds, especially downstream of areas treated by BMPs; (2) BMPs may have increased the duration of stormflow that results in downstream channel erosion; and/or (3) spurious relationships between increases in EIA, BMP implementation, and constituent inputs with development rates.     

Phosphorus loss from an agricultural watershed as a function of storm size

Phosphorus (P) loss from agricultural watersheds is generally greater in storm rather than base flow. Although fundamental to P-based risk assessment tools, few studies have quantified the effect of storm size on P loss. Thus, the loss of P as a function of flow type (base and storm flow) and size was quantified for a mixed-land use watershed (FD-36; 39.5 ha) from 1997 to 2006. Storm size was ranked by return period (<1, 1-3, 3-5, 5-10, and >10 yr), where increasing return period represents storms with greater peak and total flow. From 1997 to 2006, storm flow accounted for 32% of watershed discharge yet contributed 65% of dissolved reactive P (DP) (107 g ha(-1) yr(-1)) and 80% of total P (TP) exported (515 g ha(-1) yr(-1)). Of 248 storm flows during this period, 93% had a return period of <1 yr, contributing most of the 10-yr flow (6507 m(3) ha(-1); 63%) and export of DP (574 g ha(-1); 54%) and TP (2423 g ha(-1); 47%). Two 10-yr storms contributed 23% of P exported between 1997 and 2006. A significant increase in storm flow DP concentration with storm size (0.09-0.16 mg L(-1)) suggests that P release from soil and/or area of the watershed producing runoff increase with storm size. Thus, implementation of P-based Best Management Practice needs to consider what level of risk management is acceptable.     

SIZING OF SURFACE WATER RUNOFF DETENTION PONDS FOR WATER QUALITY IMPROVEMENT1

ABSTRACT: Historically, storm water management programs and criteria have focused on quantity issues related to flooding and drainage system design. Traditional designs were based on large rainfall‐runoff events such as those having two‐year to 100‐year return periods. While these are key criteria for management and control of peak flows, detention basin designs based on these criteria may not provide optimal quality treatment of storm runoff. As evidenced by studies performed by numerous public and private organizations, the water quality impacts of storm water runoff are primarily a function of more frequent rainfall‐runoff events rather than the less frequent events that cause peak flooding. Prior to this study there had been no detailed investigations to characterize the variability of the more frequent rainfall events on Guam. Also, there was a need to develop some criteria that could be applied by designers, developers, and agency officials in order to reduce the impact of storm water runoff on the receiving bodies. The objectives of this paper were three‐fold: (1) characterize the hourly rainfall events with respect to volume, frequency, duration, and the time between storm events; (2) evaluate the rainfall‐runoff characteristics with respect to capture volume for water quality treatment; and (3) prepare criteria for sizing and designing of storm water quality management facilities. The rainfall characterization studies have provided insight into the characteristics of rainstorms that are likely to produce non‐point source pollution in storm water runoff. By far the most significant fmdings are the development of a series of design curves that can be used in the actual sizing of storm water detention and treatment facilities. If applied correctly, these design curves could lead to a reduction of non‐point source pollution to Guam's streams, estuaries, and coastal environments.     

GENERATION OF HOURLY RAINFALL1

ABSTRACT: A rainfall model was developed to divide daily rainfall into storms and distribute storm depths over storm duration for input into the Stanford Watershed Model.     

A MODELING APPROACH FOR STORM WATER QUANTITY AND QUALITY CONTROL VIA DETENTION BASINS1

ABSTRACT: Storm water detention basins have historically been employed for quantity (i.e., flooding) control only. However, recently it has been suggested that these basins may also provide a practical means of storm water quality control. This paper presents the formulation of a mathematical modeling approach which may be used by professionals to simultaneously design detention basins for the dual purpose of storm water quantity and quality control. Model simulations demonstrate that for a given basin, pollutant removal increases as storm frequency increases. The importance of particle size distribution and settling velocity for net pollutant removal is illustrated, The design procedure is demonstrated, and pollutant loading diagrams for estimating pollutant removal as a function of storm size are developed.     

EFFECT OF SURFACE MINING ON STORM FLOW AND PEAK FLOW FROM SIX SMALL BASINS IN EASTERN KENTUCKY1

ABSTRACT: Hydrologic records from six small Eastern Kentucky watersheds were analyzed to determine the effect of surface mining on storm flows and peak flows. Average storm flow volumes were not changed by surface mining, whereas average peak flows were increased 36 percent. Peak flow increases were only in the summer. Smaller peak flows are doubled; moderate ones are increased by about a third; peak flows around 100 csm seem to be largely unaffected; and the larger peak flows may have been reduced by surface mining. The maximum annual storm flows, usually in winter or spring, appeared slightly reduced. No time trend in either storm flows or peak flows could be detected in five years of postmining record. Surface mining is not a serious floodwater discharge problem.     

DEVELOPMENT OF DESIGN STORM HYETOGRAPHS FOR CINCINNATI,OHIO1

ABSTRACT A synthetic storm rainfall hyetograph for a one-year design frequency is derived from the one-year intensity-duration curve developed for Cincinnati, Ohio. Detailed rainfall data for a three-year period were collected from three raingages triangulating the Bloody Run Sewer Watershed, an urban drainage areas of 2380 acres'in Cincinnati, Ohio. The advancement of the synthetic storm pattern is obtained from an analysis of the antecedent precipitation immediately preceding the maximum period of three selected durations. Rains which produced excessive runoff at least for some duration were considered only. The same approach can be used for other design frequencies. The purpose of this study is to provide synthetic storm hyetographs to be used as input in deterministic mathematical models simulating urban storm water runoff for the design, analysis and possible surcharge prediction of sewer systems.     

STORM WATER RUNOFF QUALITY FROM THREE LAND-USE AREAS IN SOUTH FLORIDA1

ABSTRACT: Storm water runoff studies of three small basins (20, 40, and 58 acres) in the Fort Lauderdale area of Florida were conducted by the U.S. Geological Survey in 1974–78. The basins were homogeneously developed with land uses being: commercial, single family residential, and high traffic volume highway. Synchronized data were collected for rainfall, storm water discharge, storm water quality, and bulk precipitation (rainfall plus dry fallout) quality. Analysis of the storm water discharge data showed that most runoff was from impervious areas hydraulically connected to drain inlets. Regression analyses of the storm water discharge and water quality data indicated that storm loads from the single family residential area correlated strongly with peak discharge and length of antecedent dry periods. Storm loads from the highway area correlated strongly with rainfall and less strongly with peak discharge and antecedent dry periods. Storm loads from the commercial area correlated strongly with peak discharge and rainfall, and less strongly with antecedent dry periods. On a unit area basis, the single family residential area yielded the largest loads of nitrogen, phosphorus, and dissolved solids. The commercial area yielded the largest loads of lead, zinc, and chemical oxygen demand. Yields of carbon were about the same for the three areas. Constituent loadings derived directly from the atmosphere were estimated on the basis of bulk precipitation samples and compared with storm runoff loads from the highway and commercial areas.     

ISOLATING THE RANDOM RAMSTORM COMPONENT FROM BASIN RESPONSE FACTORS IN RAINFALLRUNOFF DATA1

ABSTRACT: Gaged watersheds can provide information as to geomorphic, and geologic influence on the spatial variability of rainfall-runoff relationships. However, correlations between raingages distributed throughout the basin, and stream discharge are influenced by both storm patterns and drainage basin characteristics. Factor analysis has been applied to rainfall-runoff relationship to isolate the storm pattern from a basin response factor. Comparing two periods of time separated by eight years reveals relative stability in the rainfall attenuation (basin response) factor, while storm patterns for the two periods of record are quite disparate.