• Journal of Environmental Impact Assessment
• /
• v.11 no.4
• /
• pp.271-280
• /
• 2002

The purpose of this study is to explore the hydrological impacts and soil loss variation due to the land use change of Namak New Town development area. The analysis of hydrological effects and soil loss variation has been carried out using GIS in this study. In order to estimate the peak runoff volume, the Rational Method which is the most popular technique to predict runoff amounts is used. To estimate the soil loss in the study area, Universal Soil Loss Equation(USLE), which is one of the most comprehensive and useful technique to predict soil erosion is adopted. The result of this study has shown that the peak runoff volume and the total soil loss increase according to the land use change. The peak runoff volume and the total soil loss have been increased about 2 times and about 48 times more than that of pre development. The increasing of the peak runoff volume can be effective erosion, flooding and so on. A careful city planning is the first essential step to minimize the environmental impacts and to construct the ecological city.

• Proceedings of the KSR Conference
• /
• 2008.06a
• /
• pp.147-150
• /
• 2008

Changes in land uses at urbanizing areas are causing flooding, increase in NPS pollutants. Thus, Low Impact Development (LID) concept is now being employed in urban planning for sustainable development. Compared with the conventional BMPs, the LID is a new concept in urban planning to minimize the impacts of urbanization for site-specific LID IMPs. The objective of this study is to analyze the efficiency of LID adoption in study watershed in peak rate runoff and runoff volume reduction perspectives. The analysis revealed that the peak rate runoff and runoff volume decreased significantly with the LID adoption. This indicates that the Bimodal tram route with grass installed at the center of the road will contribute reduction in surface runoff and peak rate runoff, and also in NPS pollutant generation from the Bimodal tram route.

• Journal of Environmental Impact Assessment
• /
• v.3 no.2
• /
• pp.47-56
• /
• 1994

AGNPS model is an event-based model to analyze nonpoint-source and to examine potential water quality problems from agricultural watershed. This model uses a square grid-cell system to represent the spatial variability of watershed conditions, and simulates runoff, sediment, and nutrient transport for each cell. AGNPS model was applied on Yeonwha watershed, and the test results were compared with the measured data for runoff volume, peak runoff rate, suspended solids, and phosphorus concentration. The watershed of 278.8 ha was divided into 278 cells, each of which was 1 ha in size. The coefficients of determination for runoff volume and peak flow were (0.893 and 0.801 respectively from regression of the estimated values on the measured values. The concentration of suspendid solid was increased but decreased that of phosphate with runoff volume.

• Journal of Korean Society on Water Environment
• /
• v.29 no.1
• /
• pp.45-54
• /
• 2013

This study analyzes the reduction effects of runoff and flood damage through different arrangements of stormwater storage facilities. Three scenarios based on the spatial allocation of storage capacity are used: concentrated, decentralized and combinative. The characteristics of runoff and flood damage by scenario are compared. The XP-SWMM model is used for runoff simulation by the probable rainfall of return period. The result shows that the concentrated arrangement of storage facilities is most effective to reduce the amount of peak flow and to delay the time of peak flow. Yet, while the concentrated arrangement is most effective to reduce the inundation damage, it is not effective to reduce runoff volume. The decentralized arrangement is most effective to reduce runoff volume. The combinative arrangement is effective not only the runoff reduction but also the reduction of flood damage. The result indicates that the flood mitigation strategies against heavy rainfall need to consider decentralized on-site arrangement for the reduction of runoff volume along with concentrated off-site arrangement of storage facilities.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.44 no.3
• /
• pp.65-72
• /
• 2002

Rainfall and runoff data from a forested watershed and irrigated rice paddies at the Bal-an experimental watershed were monitored and analyzed to investigate the variations of runoff characteristics with different land use. The comparisons were conducted fourteen storm events ranging 21.8∼190.2 mm of rainfall. Field data showed that direct runoff from paddies and forested watershed are not significantly different in volume. The peak discharge from forest watershed was less than that from paddies far lighter storms, but became greater fur heavier storms. The peak runoff from the forest watershed was 39 percent greater than from the paddies. The results demonstrate that paddies play an important role to reduce peak discharge from heavy storms as compared to forest.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.31 no.1
• /
• pp.45-57
• /
• 1989

The hydrologic model FESHM was introduced and its applicability was investigated in an attempt to analyze the rainfall-runoff relationships of urban small watersheds and to hereafter predict the envi-ronmental changes. Basic data on rainfall, water level, geomorphological characterisitics and land use were obtained from Yeonwha stream watershed located in Chonju-si Dukjin-dong. WL-5 for simulation o subshed WS# 1(136.7 ha) with urban district and WL-1 for total watershed WS#5 (278.78 ha) we'e selected as gaging points. The main results gained through applications were summarized as follows. 1. Direct runoff ratio caalculated from a simple separation method for WS#5 WS# 1 was 2O~39%, 38~62%, respectively. 2. Simulations for the runoff estimation were carried out for each watershed using 5 rainfall events, the simulation errors had the range of 2~ 30%, O~ 63% and O 120 minutes for the runoff volume, peak flow and peak time, respectively. 3. The effect of landuse change by urbanization was tested to WS# 1, runoff volume before development was estimated as from tenth to twentieth against after development.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.3
• /
• pp.133-141
• /
• 2011

Urban development of basin causes increasing runoff volume and peak flowrate and shortening in time of concentration, which may cause frequent flooding downstream. An infiltration facilities are operated as a method of reducing flood discharge of urban rivers and peak flowrate. There are various types of infiltration facilities like infiltration trench and porous pavement. In this study, runoff reduction effect due to installation of infiltration facilities are performed and focused on $0.18km^2$ residential area of Ok-kye dong and $0.67km^2$ industrial area of Gong-dan dong in Gumi City. The analysis is fulfilled with comparison of total runoff volume and runoff reduction volume by using the WinSLAMM and the relation equation between area ratio of infiltration facilities and ratio of runoff reduction are derived and peak flow reduction effect for installation of infiltration facilities is analyzed.

• Proceedings of the Korean Society of Agricultural Engineers Conference
• /
• 2000.10a
• /
• pp.72-77
• /
• 2000

The purpose of this study were to monitor rainfall and runoff data from paddy blocks and forest areas at the Balan Experimental Watershed, and to investigate the variations of runoff characteristics with different land use. Field data showed that the total runoff from paddies and forest areas are not significantly different in volume. The peak discharge from forest areas was less than that from paddies for lighter storms, but became greater for heavier storms. The results demonstrate that paddies play an important role to reduce peak discharge from heavy storms as compared to forest.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.51 no.6
• /
• pp.105-114
• /
• 2009

With urbanization in many countries, many pervious areas are being converted into impervious areas. These land use changes cause many negative impacts on runoff and water quality in the areas. Especially runoff volume and peak runoff are increasing with urbanization. In addition to the increased runoff, more pollutant transports to the downstream areas. For these reasons, Low Impact Development (LID) are nowadays being introduced in urban planning. For environment-friendly and economical urban development, the LID Integrated Management Practices (IMPs) are applied in various urban development. However, exact effects on runoff and water quality of various LID IMPs are not assessed with proper LID evaluation technique. Thus, the SWMM (Storm Water Management Model) 5.0 model was slightly modified to simulate the effect of infiltration manhole on runoff and water quality. For comparison of runoff and TSS (Total Suspended Solids) from the study area (26.5 ha), three scenarios were made in this study. It was found that runoff volume, peak runoff, and TSS could be reduced with infiltration manholes and pervious pavements to some degree. Although, there are many limitations in the analysis of LID effects on runoff and TSS, similar trends shown in this study would be expected with site-specific LID IMPs. Thus, it is strongly recommended that various site-specific LID IMPs, such as infiltration facilities, should be applied as much as possible for environment-friendly urban planning.

• Journal of The Korean Society of Agricultural Engineers
• /
• v.52 no.4
• /
• pp.1-10
• /
• 2010

In this study, two estimation equations for preparing stream data for distributed storm runoff model were developed by analyzing the nonlinear relation between upstream flow-length and stream width, and between upstream flow-length and stream bed-slope. The equations for stream cell were tested in Chungjudam watershed (6,661 $km^2$) using KIMSTORM. Six storm events occurring between 2003 and 2008 were selected for the model calibration and verification before the test of equations. The average values of the Nash-Sutcliffe model efficiency (ME), the volume conservation index (VCI), the relative error of peak runoff rate (EQp), and the difference of time to peak runoff (DTp) were 0.929, 1.035, 0.037, and -0.406 hr for the calibrated four storm events and 0.956, 0.939, 0.055, and 0.729 hr for the two verified storm events respectively. The estimation equations were tested to the storm events, and compared the flood hydrograph. The test result showed that the estimation equation of stream width reduced the peak runoff and delaying the time to peak runoff, and the estimation equation of stream bed-slope showed the opposite results.