• Journal of Korean Society of Environmental Engineers
• /
• v.33 no.6
• /
• pp.439-446
• /
• 2011

In this research, enhanced land-cover classification methods using high-resolution satellite image (HRSI) and GIS in terms of practicality and accuracy was proposed. It aims for understanding non-point pollutant origin/loading, assessment the efficiency of rainfall storage/infiltration facilities and sounds water-environment management. The result of applying enhanced land-cover classification methods to the urban region verifies that roof and road area are including various vegetations such as roof garden, flower bed in the median strip and street tree. This accounts for 3% of total study area, and more importantly it was counted as impervious area by GIS alone or conventional indoor work. The feasibility of the method was assessed by applying to rainfall-runoff analysis for three weak rainfall in the range of 7.1-10.5 mm events in 2000, Chiba, Japan. A good agreement between simulated and observed runoff hydrograph was obtained. In comparison, the hydrograph simulated with land-use parameters by the detailed land-use information of 10m grid had an error between 31%~71%, while enhanced method showed 4% to 29%, and showed the improvement particularly for reproducing observed peak and recession flow rate of hydrograph in weak rainfall condition.

• Journal of the Korean Institute of Landscape Architecture
• /
• v.43 no.3
• /
• pp.13-26
• /
• 2015

Many urban areas in Korea suffer from repeated flood damage during intensive rainfall due to an increase in impervious areas caused by rapid urbanization and deteriorating sewage systems. A centralized stormwater management system has caused severe flood damage in an area that has proven unable to accommodate recent climate change and a rise in precipitation. Most flooding prevention projects that have been recently implemented focus on increasing drainage system capacity by expanding the size of sewer pipes and adding pumping stations in downstream areas. However, such measures fail to provide sustainable solutions since they cannot solve fundamental problems to reduce surface runoff caused by urbanization across the watershed. A decentralized stormwater management system is needed that can minimize surface runoff and maximize localized retention capacity, while maintaining the existing drainage systems. This study proposes a stormwater management corridor for the flood-prone watershed in the city of Dongducheon. The corridor would connect the upstream, midstream, and downstream zones using various methods for reducing stormwater runoff. The research analyzed surface runoff patterns generated across the watershed using the Modified Rational Method considering the natural topography, land cover, and soil characteristics of each sub-watershed, as well as the urban fabric and land use. The expected effects of the design were verified by the retainable volume of stormwater runoff as based on the design application. The results suggest that an open space network serve as an urban green infrastructure, potentially expanding the functional and scenic values of the landscape. This method is more sustainable and effective than an engineering-based one, and can be applied to sustainable planning and management in flood-prone urban areas.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.19 no.4
• /
• pp.36-51
• /
• 2016

This study assessed urban flood risk using a Bayesian probability statistical method and GIS incorporating a climate change scenario. Risk is assessed based on a combination of hazard probability and its consequences, the degree of impact. Flood probability was calculated on the basis of a Bayesian model and future flood occurrence likelihoods were estimated using climate change scenario data. The flood impacts include human and property damage. Focusing on Seocho-gu, Seoul, the findings are as follows. Current flood probability is high in areas near rivers, as well as low lying and impervious areas, such as Seocho-dong and Banpo-dong. Flood risk areas are predicted to increase by a multiple of 1.3 from 2030 to 2050. Risk assessment results generally show that human risk is relatively high in high-rise residential zones, whereas property risk is high in commercial zones. The magnitude of property damage risk for 2050 increased by 6.6% compared to 2030. The proposed flood risk assessment method provides detailed spatial results that will contribute to decision making for disaster mitigation.

• Journal of Wetlands Research
• /
• v.18 no.4
• /
• pp.342-349
• /
• 2016

Andong belongs to the Nakdong River Basin, Nakdong River is flowing through the city, including Andong dam and Imha dam. The runoff due to provincial transfer and impervious area has been increasing by urbanization increases and nonpoint source loads. In this study, we evaluate the runoff and nonpoint pollution loads in accordance with the development targeted at selected urban water cycle leading to Andong city. Andong city leading to the water cycle plan to evaluate the directly runoff and BOD, T-N and T-P nonpoint pollutant loads using the CN into account the temporal and spatial changes. Evaluation, direct runoff per year is 10.41 % if the green roof and a water permeable pavement replacement, water cycle parks and streets compositions, City impermeable layer improvements to be business including four kinds of scenario is applied to both the development and the BOD non-point pollutant loads 20.56%, T-N 9.55% and T-P pollution and nonpoint loads was investigated to be reduced 14.29%. Four kinds of low lapse rate of the development scenario of the highest thing urban impervious surface was investigated by improving business development prior year annual direct runoff is 6.25 %, BOD nonpoint pollution loads are 11.84%, T-N nonpoint pollution loads are 4.46 % and T-P was investigated by reducing pollutant loads to be 10.20%.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.1150-1155
• /
• 2006

대부분의 도시지역은 불투수면적 비율이 상당히 높은 특징으로 인한 유출용적 및 첨두유출량의 증가와 외수위보다 낮은 지반고의 지형학적 특징으로 인한 내수배제의 불량으로, 저지대의 침수위험도가 상당히 높다. 이러한 이유로, 빈도별 설계홍수량을 산정하여 침수위험지역을 파악하고 관리하는 공간적인 치수관리가 이루어지고 있지만, 효율적인 치수관리를 위해서는 공간적인 측면뿐 아니라, 침수위험지역 내 침수발생의 시간적인 측면도 고려하는 것이 필요하다. 본 연구에서는 침수위험지역 내 내수침수발생에 대하여 공간적.시간적으로 살펴보고, 내수침수발생 위험지역 및 우선관리지역을 선정하였다. 대상유역으로는 안양천 유역에서 대부분의 침수가 발생하는 서울시에 포함된 안양천 하류유역으로 하였다. 서울시에 포함된 안양천 하류지역에서 내수침수발생의 주원인으로는 외수위보다 낮은 지반고와 배수계통의 통수능력 부족으로 나타나고 있어, 이들 지역의 침수위험지역을 파악하기 위해 하도 및 관거의 유출해석에 우수한 SWMM 모형의 EXTRAN block을 이용하여 모의를 실시하고 맨홀이 월류되는 지역을 내수침수 위험지역으로 선정하였다. 각 빈도별 지속시간별 모의결과, 목감천 하류부의 고척 1동, 신월 1동, 화곡 2동, 도림천과 봉천천, 대방천이 만나는 구로동, 대림 1동, 대방동에서 침수가 발생하기 시작하였다. 이들 지역은 또한 10년에서 30년 빈도별 모의에서도 모두 침수위험이 높은 지역으로 선정되어, 우선관리지역으로 선정하였다. 우선관리지역의 선정은 홍수예.경보 측면에서는 주민의 신속한 대피와 같은 홍수대처능력과 치수관리측면에서는 소요되는 자원의 효율적 배분을 기대할 수 있을 것으로 판단된다. 대상으로 홍수범람모의시스템을 구축하여 분석결과를 피해지역주민 및 관련기관 실무자들에게 제공함으로써 시간과 공간에 구애받지 않는 재해관리와 신속한 재해 상황 대처가 가능해 질 것으로 사료된다.는 또 다른 형태의 주제도라고 볼 수 있으며, 이를 구축하기 위해서는 자료변환 및 가공이 필요하다. 즉, 각 상습침수지구에 필요한 지형도는 국립지리원에서 제작된 1:5,000 수치지형도가 있으나 이는 자료가 방대하고 상습침수지구에 필요하지 않은 자료들을 많이 포함하고 있으므로 상습침수지구의 데이터를 인터넷을 통해 서비스하기 위해서는 많은 불필요한 레이어의 삭제, 서비스 속도를 고려한 데이터의 일반화작업, 지도의 축소.확대 등 자료제공 방식에 따른 작업 그리고 가시성을 고려한 심볼 및 색채 디자인 등의 작업이 수반되어야 하며, 이들을 고려한 인터넷용 GIS기본도를 신규 제작한다. 상습침수지구와 관련된 각종 GIS데이타와 각 기관이 보유하고 있는 공공정보 가운데 공간정보와 연계되어야 하는 자료를 인터넷 GIS를 이용하여 효율적으로 관리하기 위해서는 단계별 구축전략이 필요하다. 따라서 본 논문에서는 인터넷 GIS를 이용하여 상습침수구역관련 정보를 검색, 처리 및 분석할 수 있는 상습침수 구역 종합정보화 시스템을 구축토록 하였다.N, 항목에서 보 상류가 높게 나타났으나, 철거되지 않은 검전보나 안양대교보에 비해 그 차이가 크지 않은 것으로 나타났다.의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상

• Journal of Korea Water Resources Association
• /
• v.51 no.2
• /
• pp.121-129
• /
• 2018

Rainfall falling in the impervious area of the cities flows over the surface and into the stormwater pipe networks to be discharged from the catchment. Therefore, it is very important to determine the size of stormwater pipes based on the peak discharge to mitigate urban flood. Climate change causes the severe rainfall in the small area, then the peak rainfall can not be discharged due to the capacity of the stormwater pipes and causes the urban flood for the short time periods. To mitigate these type of flood, the large stormwater pipes have to be constructed. However, the economic factor is also very important to design the stormwater pipe networks. In this study, 4 urban catchments were selected from the frequently flooded cities. Rainfall data from Seoul and Busan weather stations were applied to calculate runoff from the catchments using SWMM model. The characteristics of the peak runoff were analyzed using linear regression model and the 95% confidence interval and the coefficient of variation was calculated. The drainage density was calculated and the runoff characteristics were analyzed. As a result, the drainage density were depended on the structure of stormwater pipe network whether the structures are dendritic or looped. As the drainage density become higher, the runoff could be predicted more accurately. it is because the possibility of flooding caused by the capacity of stormwater pipes is decreased when the drainage density is high. It would be very efficient if the structure of stormwater pipe network is considered when the network is designed.

• Journal of Wetlands Research
• /
• v.11 no.3
• /
• pp.161-169
• /
• 2009

Rainfall-runoff procedures of urban area are more complicated than agricultural procedures. Extension and development of town leads to shift of the basin characteristics and it makes more difficult to use runoff models. In this study, the changes of hydrologic circumstances and the shape of hydrograph due to the urbanization in Cho-kyung river basin has been assessed which is the representative urban stream in Jeonju city. The urbanization can be classified as four typical year. The natural basin period(1924) that is before the urban development, the period of construction of Chonbuk National University campus (1963), the period of construction of residential area(1986), and urbanization process has been finally completed in 1995. The rainfall-runoff analysis has been carried out by Storm Water Management Model(SWMM) under condition of the basin characteristics and impervious area of each period. It was found that hydrologic characteristics such as river length, roughness coefficient, and coefficient of surface storage has been decreased. According to the land use change, the pervious area was decreased from 97.7% to 42%, while the impervious area was increased from 0.6% to 34%. The time of concentration was shorten from 90 minutes to 37 minutes. Along with decreasing the time of concentration, the peak discharge was increased from $4.37m^3/s$ to $111.13m^3/s$, and the runoff rate was also increased from 0.8% to 68%.

• Journal of the Korean Regional Science Association
• /
• v.35 no.4
• /
• pp.61-73
• /
• 2019

Urban development and densification have led to the Urban Heat Island Effect, in which the temperature of urban space is higher than the surrounding areas, and the intensity is increasing with climate change. In addition, when the city's air temperature rises in summer, low-income, elderly population, and socially vulnerable people who have health problems lack the ability to cope with the elevated heat environment. Therefore, this study aimed to identify the urban heat island area of Seoul through Hotspot analysis, which is a spatial statistics technique, and explored physical environments, demographic and socioeconomic characteristics of urban heat island effect areas using logistic regression models. This study performed urban heat island hotspot analysis using the average air temperatures of the 423 administrative dongs in Seoul. Analysis results identified that the urban heat islands were concentrated in Jung-gu, Jongno-gu, Yongsan-gu, and Yeongdeungpo-gu. Logistic regression analysis results indicated that urban heat island areas of Seoul were affected by residential floor area ratio, commercial facility floor area ratio, overall floor area ratio, impervious surface ratio, and normalized difference vegetation index(NDVI). In addition, as a result of analyzing the vulnerable area of thermal environment considering the demographic and socioeconomic characteristics of the heat island area, urban heat island areas of Seoul were significantly associated with the proportion of low-income elderly living alone. The result of this study provided useful insights for urban thermal environmental design and policy development that could improve the thermal environment for the socially disadvantaged urban population.

• Journal of Korean Society on Water Environment
• /
• v.32 no.1
• /
• pp.30-35
• /
• 2016

Urban areas generate large amounts of stormwater and non-point source (NPS) pollutants during rainfall events. These are caused by various land use runoffs, vehicular and human activities and increased impervious cover. The increased runoff and NPS pollutants cause water quality deterioration in the receiving waters and adversely affect the aqua-ecosystem. These environmental impacts could be reduced through the application of low impact development (LID) techniques. In Korea, more than 80% of the total rainfall occurs in summer and most of these were 10 mm or less. Therefore, if the LIDs developed were able to cope with rainfall of 10 mm and below, NPS management could be efficiently conducted. This research was performed to determine the effect of varying amounts of rainfall on the performance capability of an established infiltration and filtration facility (IF facility) that can be applied to Korea's common rainfall ranges. The IF facility area was 1.75% of the catchment area, however the facility treated more than 40% and 60% runoff volume and pollutant reduction respectively for a 10 mm rainfall. Lastly, higher volume and pollutant reduction could be attained when the LID area was at least 2% of the entire catchment.

• Journal of Wetlands Research
• /
• v.18 no.2
• /
• pp.173-182
• /
• 2016

Although the ecosystem extends numerous functions for the benefit of humankind, construction of horticultural facilities can potentially lead to the degeneration of some of these functions owing to the expansion of impervious regions and loss of habitats. Thus, this study aimed to examine the effect of construction of horticultural facilities on plant biodiversity. Analysis of the vegetation distribution characteristics showed that horticultural facilities had significantly lower plant diversity than did rice paddies. Hence, the proposed approach involved low-impact development, arrangement of habitat space, plant preservation, restricted use of chemical fertilizer, habitat creation, and reduced preservation cost. Lifestyle analysis suggested the importance of developing favorable environments for the growth of annual plants and aquatic plants. In all, 20 species of naturalized plants belonging to 10 families were identified. Furthermore, the proportion of these naturalized plants was higher in glass greenhouses and multi-span greenhouses, suggesting the advantages of employing natural soil mulching while avoiding concrete mulching. Statistical analysis was performed to validate the results, which suggested that impervious regions be converted to natural soils. Collectively, the findings of this study are expected to be used for establishing policies for the construction of eco-friendly and ecological horticultural facilities; this may aid the maintenance of sustainable agricultural landscapes and large-scale development of the reclaimed lands.