Cumulative Runoff Volume Research Articles

On-site 방식 빗물관리를 위한 건축물 지붕면의 유출특성 경험식 수립

본 연구는 현지(on-site) 빗물관리에 필요한 지붕면 누적유출용적 예측을 위한 경험식을 제안하였다. 건축물 지붕면은 좁은 면적으로 인해 기존 유출해석 기법의 적용이 어려운 것으로 파악되었으며, 지붕면 유출조건을 고려한 강우깊이(D)-누적유출용적(V)간의 이론적 관계식을 수립하였다. 2005년부터 2007년까지 2년간 실제 강우량과 지붕면의 유출용적을 측정하여 이론적 관계식으로 계산된 누적유출용적과 실측 누적유출용적 자료를 비교 검토하였다. 실측자료의 분석결과를 바탕으로 시간별 강우깊이 변화에 따른 누적유출용적을 예측할 수 있는 경험적 유출식을 얻었다. 본 경험식으로 강우관측 자료 또는 강우주상도와 지붕면의 면적으로부터 간편하게 실제에 가까운 누적유출용적의 시간별 변화를 예측할 수 있으며, 이 결과는 각종 빗물관리시설의 용량 결정은 물론, 빗물관리시설 통해 지붕면에서 도시배수관으로 유입되는 유량 변화 예측에도 활용이 가능할 것이다. This study proposes an experimental formula for cumulative runoff analysis in building roof for on-site rainwater management. We can not find an appropriate method for roof runoff analysis because of its small area scale. A new runoff equation formula for rainfall depth(D) and cumulative runoff volume(V) is developed on roof runoff conditions. Reliability of the formula is verified with field experimental runoff monitoring for two years in two buildings of rainwater management system. This experimental runoff formula can root the cumulative runoff volume from roof area and rainfall depth, then develop reasonable inflow condition for rainwater retention tank design.

Long Term Monitoring of Storm Surface Runoff from Urban Pavement Road in Korea

Long term monitoring was conducted to investigate a surface runoff of pollution from urban highway. The monitoring data was collected for 18 rainfall events and was used to correlate pollution load to various parameters, such as rainfall intensity, antecedent dry days and total discharge flow. Runoff coefficient and seasonal variation were also evaluated. The mean runoff coefficient of the highway was 0.823(range; 0.4687~0.9884), and wash-off ratio for CODMn and SS loads was 72.6% and 64.3%, respectively. For the initial rainfall event, the runoff EMC of CODMn was high in summer and the EMC of SS was high in autumn season. However the seasonal variation of T-N and T-P was not significant. The discharged CODMn-EMC was 147.6 mg/L~9.0 mg/L on the generated CODMn-EMC of 98.8 mg/L~8.9 mg/L. While the generated EMC of SS was in 285.7 mg/L~20.0 mg/L and its discharged EMC was in 190.4 mg/L~8.0 mg/L. EMC of pollutants was not directly related to the first flush rainfall intensity and the antecedent dry days. But the correlation was relatively high between EMC and cumulative runoff flow volume. The trend of EMC was reduced with the cumulative runoff flow volume.

Effects of Container Spacing Practice and Fertilizer Placement on Runoff from Overhead-Irrigated Sweet Viburnum

Abstract Information on how management practices affect runoff volume and nutrient content is needed to improve irrigation and fertilizer efficiency while minimizing environmental impacts. Runoff (leachate plus unintercepted irrigation and rain) was collected weekly for 20 weeks during production of sweet viburnum (Viburnum odoratissimum (L.) Ker-Gawl.) in trade #1 (2.7 liter) containers fertilized with 15 g (0.53 oz) of a resin-coated, controlled-release fertilizer Osmocote 18N–2.6P–10K (18–6–12), 8–9 month 21C (70F)] and overhead-irrigated with water at 1 cm/day (0.39 in). Treatments were a factorial arrangement of two container spacing practices [spaced at planting (SP) or spaced midseason (SM)] and two fertilizer placement methods [incorporated (INC) or surface-applied (SURF)]. Cumulative runoff volume averaged 1590 liters/m2 (3900 gal/100 ft2) or 66% of irrigation plus rain and was 9% higher for SP than SM. A 37% reduction in shoot dry weight of SP versus SM plants was attributed to heat stress in SP containers. SURF decreased N, P, and K leaching losses (mg/container) 42, 42, and 25%, respectively, at SP and 16, 25, and 4%, respectively, at SM. Nutrient leaching losses as a percent of applied were 11–18% for N, 7–13% for P, and 19–28% for K. Total nutrient loads in runoff were 4.6–11.1 g/m2 for N, 0.48–1.25 g/m2 for P, and 5.8–10.1 g/m2 for K with peak nutrient loss occurring during the first two weeks after planting.

Runoff and soil loss under individual plants of a semi‐arid Mediterranean shrubland: influence of plant morphology and rainfall intensity

AbstractThe influence of plant morphology and rainfall intensity on soil loss and runoff was determined at the plant scale for three representative species of a semi‐arid patchy shrubland vegetation of east Spain, representing contrasting canopy structures and plant phenologies (Rosmarinus officinalis, Anthyllis cytisoides and Stipa tenacissima).Twenty‐seven microplots of less than 1 m2, each containing one single plant, were built to quantify runoff volume and sediment yield under the canopies of the three species. Runoff and rates of soil loss measured in these plots under natural rainfall conditions were compared with control microplots built in the bare inter‐plant areas. Precipitation was automatic‐ally recorded and rainfall intensity calculated over a two‐year period.Results indicated that individual plants played a relevant role in interrill erosion control at the microscale. Compared with a bare soil surface, rates of soil loss and runoff reduction varied strongly depending on the species. Cumulative soil loss was reduced by 94·3, 88·0 and 30·2 per cent, and cumulative runoff volume was reduced by 66·4, 50·8 and 18·4 per cent under the Rosmarinus, Stipa and Anthyllis canopies, respectively, compared with a bare surface. Anthyllis was significantly less efficient than the two other species in reducing runoff volume under its canopy. Differences between species could only be identified above a rainfall intensity threshold of 20 mm h−1. The different plant morphologies and plant compon‐ents explained the different erosive responses of the three species. Canopy cover played a major role in runoff and soil loss reduction. The presence of a second layer of protection at the soil surface (litter cover) was fundamental for erosion control during intense rainfall. Rainfall intensity and soil water status prior to rainfall strongly influenced runoff and soil loss rates. The possible use of these species in restoration programmes of degraded areas is discussed. Copyright © 2006 John Wiley & Sons, Ltd.

Characterizations of the First Flush in Storm Water Runoff from an Urban Roadway

Storm water runoff from urban roadways contains anthropogenic pollutants, which are mainly generated from traffic-related activities. The purpose of this study was to evaluate the characteristics of pollutants from the roadway runoff as well as first flush effects. Storm water runoff was sampled during five storm events from the experimental site in Otsu, Shiga, Japan. From the hydrographs and pollutographs for the roadway runoff, the concentration of pollutants increased with increasing runoff flow in the low flow rate event, but did not significantly increase in the high flow rate event. Moreover, according to the analysis of cumulative pollutant mass versus runoff volume curves from five storm events, the first 50% of the runoff volume transported 62% of TOC and Mo, 60% of SS, 59% of Fe, Mn and Cu, 58% of Ni, 57% of Cd and Pb, 56% of Al, 55% of Zn, and 54% of Cr, as the mean values. The first 30% and 80% of the runoff volume also transported 34-43% mass of the pollutants and 82-88% mass of the pollutants, respectively. This study for storm water runoff may also provide useful information to correctly design treatment facilities, such as detention tanks and ponds, filtration and adsorption systems.

Seasonal first flush phenomenon of urban stormwater discharges

California's climate, typified by winter and spring precipitation and summer drought, is often called a Mediterranean climate, and creates a long period for pollutant build-up. The initial storms of the winter season usually have higher pollutant concentrations, which is called a seasonal first flush. To investigate the existence of a seasonal first flush, we analyzed four major data sets, collected over the 1999-2000 to 2002-2003 wet seasons. Trends in seasonal loads were quantified by plotting pollutant concentrations or cumulative pollutant load versus cumulative rainfall or cumulative runoff volume. Pollutant concentrations in the first part of the wet season were ranged from 1.2 to 20 times higher than concentrations near the end of the season, and mass emission rates were similarly higher at the beginning of the season. A seasonal first flush existed for most cases and was strongest for organics, minerals and heavy metals except lead. This result suggests that applying treatment Best Management Practices (BMPs) early in the season could remove several times more pollutant mass than randomly timed or uniformly applied BMPs.

Characterisation of the performance of an off line storage tank

A stormwater facility consisting of a hydrodynamic separator as an overflow device, an open concrete storage tank and two subsequent open earth retention basins was investigated. The results are used to characterise the qualitative performance of the storage tank. By evaluating the cumulative runoff volume and settleable solids load it is shown that the qualitative performance can be characterised by two effects: pollutants are retained because runoff is stored until the tank starts to overflow; pollutants are retained because the tank operates as a clarifier during the overflow period. The influencing factors on these two processes are discussed.

Characterisation of the performance of an off line storage tank

A stormwater facility consisting of a hydrodynamic separator as an overflow device, an open concrete storage tank and two subsequent open earth retention basins was investigated. The results are used to characterise the qualitative performance of the storage tank. By evaluating the cumulative runoff volume and settleable solids load it is shown that the qualitative performance can be characterised by two effects: pollutants are retained because runoff is stored until the tank starts to overflow; pollutants are retained because the tank operates as a clarifier during the overflow period. The influencing factors on these two processes are discussed.