• 한국물환경학회지
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• 제34권4호
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• pp.382-390
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• 2018

In this study, the LIDMOD3 was developed to design and evaluate low impact development (LIDMOD). In the same fashion, the LIDMOD3 employs a curve number (NRCS-CN) method to estimate the surface runoff, infiltration and event mean concentration as applicable to pollutant loads which are based on a daily time step. In these terms, the LIDMOD3 can consider a hydrologic soil group for each land use type LID-BMP, and the applied removal efficiency of the surface runoff and pollutant loads by virtue of the stored capacity, which was calculated by analyzing the recorded water balance. As a result of Model development, the LIDMOD3 is based on an Excel spread sheet and consists of 8 sheets of information data, including: General information, Annual precipitation, Land use, Drainage area, LID-BMPs, Cals-cap, Parameters, and the Results. In addition, the LIDMOD3 can estimate the annual hydrology and annual pollutant loads including surface runoff and infiltration, the LID efficiency of the estimated surface runoff for a design rainfall event, and an analysis of the peak flow and time to peak using a unit hydrolograph for pre-development, post-development without LID, and as calculated with LID. As a result of the model application as applied to an apartment, the LIDMOD3 can estimate LID-BMPs considering a well spatical distributed hydroloic soil group as realized on land use and with the LID-BMPs. Essentially, the LIDMOD3 is a screen level and simple model which is easy to use because it is an Excel based model, as are most parameters in the database. This system can be expected to be widely used at the LID site to collect data within various programmable model parameters for the processing of a detail LID model simulation.

• 대한원격탐사학회지
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• 제26권3호
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• pp.297-304
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• 2010

Since the change in Doppler centroid according to moving targets brings alteration to the phase in azimuth differential signals of synthetic aperture radar (SAR) data, one can measure the velocity of the moving targets using this effect. In this study, we will investigate theoretically measuring the velocity of an object from azimuth differential signals by using range compressed data which is the interim outcome of treatment from the simulated SAR raw data of moving targets on the background of sea clutter. Also, it will provide evaluation for the elements that affect the estimation error of velocity from a single SAR sensor. By making RADARSAT-1 simulated image as a specific case, the research includes comparisons for the means of velocity measurement classified by the directions of movement in the four following cases. 1. A case of a single target without currents, 2. A case of a single target with tidal currents of 0.5 m/s, 1 m/s, and 3 m/s, 3. A case of two targets on a same azimuth line moving in a same direction and velocity, 4. A case of a single target contiguous to land where radar backscatter is strong. As a result, when two moving targets exist in SAR image outside the range of approximately 256 pixels, the velocity of the object can be measured with high accuracy. However, when other moving targets exist in the range of approximately 128 pixels or when the target was contiguous to the land of strong backscatter coefficient (NRCS: normalized radar cross section), the estimated velocity was in error by 10% at the maximum. This is because in the process of assuming the target's location, an error occurs due to the differential signals affected by other scatterers.

• 한국물환경학회지
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• 제27권4호
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• pp.405-412
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• 2011

Increased Non-permeable areas which have resulted from civilization reduce the volume of groundwater infiltration that is one of the important factors causing water shortage during a dry season. Thus, seeking the efficient method to analyze the volume of groundwater in accurate should be needed to solve water shortage problems. In this study, two different watersheds were selected and precipitation, soil group, and land use were surveyed in a particular year in order to figure out the accuracy of estimated infiltration recharge ratio compared to Web-based Hydrograph Analysis Tool (WHAT). The volume of groundwater was estimated considering Antecedent soil Moisture Condition (AMC) and Curve Number (CN) using Long Term Hydrologic Impact Assessment (L-THIA) model. The results of this study showed that in the case of Kyoung-an watershed, the volume of both infiltration and baseflow seperated from WHAT was 46.99% in 2006 and 33.68% in 2007 each and in Do-am watershed the volume of both infiltration and baseflow was 33.48% in 2004 and 23.65% in 2005 respectively. L-THIA requires only simple data (i.e., land uses, soils, and precipitation) to simulate the accurate volume of groundwater. Therefore, with convenient way of L-THIA, researchers can manage watershed more effectively than doing it with other models. L-THIA has limitations that it neglects the contributions of snowfall to precipitation. So, to estimate more accurate assessment of the long term hydrological impacts including groundwater with L-THIA, further researches about snowfall data in winter should be considered.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.353-353
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• 2023

기후변화에 대응하는 도시유출 저감과 열섬효과를 방지하기 위해 투수블럭 시공이 증가 추세 있으나, 투수블럭과 하부 도로포장체에 대한 강우모사 시험시 토양함수율 설정기준을 정립할 필요가 있다. 유역 혹은 시험체의 유출량 예측에는 토지 이용에 따라 미국자연자원보호청(Natural Resources Conservation Service, NRCS)의 SCS 유효우량 산정 방법을 통해 CN을 활용할 수 있으며, 이때 유역 혹은 시험체의 선행강우일수에 따라 유출량 결과가 큰 차이가 발생한다. 연구를 위해 시험실이 위치하고 있는 부산시와 양산시 무강우 일수(10년, 2012~2021)를 홍수기, 비홍수기 각각 분석한 결과에 따라, 투수블록 포장체의 CN 산정을 위해 자연강우 이후 시험시 AMC조건을 따르며, 무강우일수 5일 이내에는 비성수기 12.7~27.94mm, 성수기 35.56~53.34mm의 평균강우 20.32mm, 44.45mm에 해당하는 체적의 실험수를 사전에 살수한 후 강우모의시험을 진행한다. 사전살수를 통해 하부기층 토양을 AMC-II 기준에 맞추고, 강우모의 시험을 통해 CN(II) 산정한다. 동일기준에서 진행된 시험 결과, 일정한 유출을 확인하였으며, 적용에 일관성을 유지할 수 있었다. 따라서 토양종류와 토양함수조건에 의거 투수블록 포장 시험체의 CN을 산정을 통해, 도시홍수 유출모형에 적용할 수 있다. 53.34mm 이상의 자연강우시 모니터링을 통한 CN(III)을 산정하여CN(II)로 환산하여 경제적이고 합리적인 유출량을 산정한다.

• 한국농공학회논문집
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• 제65권4호
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• pp.25-32
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• 2023

KDS (Korean Design Standard) for agricultural drainage is a planning standard that helps determine the appropriate capacity and type of drainage facilities. The objective of this study was to analyze the inundation of the agricultural basin considering the current design standard and the critical rainfall duration. This study used the rainfall durations of 1-48 hour, and the time distribution method with the Chicago and the modified Huff model. For the runoff model, the NRCS (Natural Resources Conservation Service) unit hydrograph method was applied, and the inundation depth and duration were analyzed using area-elevation data. From the inundation analysis using the modified Huff method with different rainfall durations, 4 hours showed the largest peak discharge, and 11 hours showed the largest inundation depth. From the comparison analysis with the current method (Chicago method with a duration of 48 hours) and the modified Huff method applying critical rainfall duration, the current method showed less peak discharge and lower inundation depth compared to the modified Huff method. From the simulation of changing values of drainage rate, the duration of 11 hours showed larger inundation depth and duration compared to the duration of 4 hours. Accordingly, the modified Huff method with the critical rainfall duration would likely be a safer design than the current method. Also, a process of choosing a design hydrograph considering the inundation depth and duration is needed to apply the critical rainfall duration. This study is expected to be helpful for the theoretical basis of the agricultural drainage design standards.

• 농촌계획
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• 제21권3호
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• pp.171-179
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• 2015

The objectives of this research have been focussed on 1) developing prediction techniques for the flash flood and landslide based on rainfall prediction data in agricultural area and 2) developing an integrated forecasting system for the abrupt disasters using USN based real-time disaster sensing techniques. This study contains following steps to achieve the objective; 1) selecting rainfall prediction data, 2) constructing prediction techniques for flash flood and landslide, 3) developing USN and communication network protocol for detecting the abrupt disaster suitable for rural area, & 4) developing mobile application and SMS based early warning service system for local resident and tourist. Local prediction model (LDAPS, UM1.5km) supported by Korean meteorological administration was used for the rainfall prediction by considering spatial and temporal resolution. NRCS TR-20 and infinite slope stability analysis model were used to predict flash flood and landslide. There are limitations in terms of communication distance and cost using Zigbee and CDMA which have been used for existing disaster sensors. Rural suitable sensor-network module for water level and tilting gauge and gateway based on proprietary RF network were developed by consideration of low-cost, low-power, and long-distance for communication suitable for rural condition. SMS & mobile application forecasting & alarming system for local resident and tourist was set up for minimizing damage on the critical regions for abrupt disaster. The developed H/W & S/W for integrated abrupt disaster forecasting & alarming system was verified by field application.

• 한국지리정보학회지
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• 제21권3호
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• pp.48-62
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• 2018

본 연구에서는 2013년 7월 강원도 춘천시와 홍천군에 위치한 대룡산에서 발생한 토석류 산사태 현장 51개소를 조사하고 강우와 현장조사 자료를 바탕으로 토석류의 거동특성을 분석하였다. 사면형과 계곡형 토석류에 따라 발생부와 퇴적부의 위치 및 경사 그리고 침식 폭 및 두께를 토석류 전 구간에 대해 조사하였다. 또한, 1:5,000의 수치지형도를 통해 대룡산의 DEM(Digital Elevation Model)을 구축하고 SINMAP(Stability INdex MAPping)을 이용하여 산사태 위험도를 평가하고 실제발생 위치와 비교 분석하였다. 분석결과 사면형 토석류는 위험지역과 실제발생 위치가 유사한 것으로 나타났으며, 계곡형의 경우 SINMAP(Stability INdex MAPping)계산상 계산되는 지형학적 습윤지수를 통해 발생위치를 추정하였다. 또한, 미국 NRCS에서 제안한 매개변수 투수량계수/지하수함양률(T/R)에 대한 4가지 조건별 해석 결과 현장조사 결과와 다소 차이를 보였으며, 투수량계수/지하수함양률(T/R)의 값이 작을수록 위험도가 높게 나타나는 경향을 보였다.

• 한국물환경학회지
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• 제23권6호
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• pp.897-905
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• 2007

Approximately 70% of Korea is composed of forest areas. Especially 48% of agricultural field is practiced at highland areas over 400 m in elevation in Kangwon province. Over 90% of highland agricultural farming is located at Kangwon province. Runoff characteristics at the mountainous area such as Kangwon province are largely affected by steep slopes, thus runoff estimation considering field slopes needs to be utilized for accurate estimation of direct runoff. Although many methods for runoff estimation are available, the Soil Conservation Service (SCS), now Natural Resource Conservation Service (NRCS), Curve Number (CN)-based method is used in this study. The CN values were obtained from many plot-years dataset obtained from mid-west areas of the United States, where most of the areas have less than 5% in slopes. Thus, the CN method is not suitable for accurate runoff estimation where significant areas are over 5% in slopes. Therefore, the CN values were adjusted based on the average slopes (25.8% at Doam-dam watershed) depending on the 5-day Antecedent Moisture Condition (AMC). In this study, the CN-based Long-Term Hydrologic Impact Assessment (L-THIA) direct runoff estimation model used and the Web-based Hydrograph Analysis Tool (WHAT) was used for direct runoff separation from the stream flow data. The $R^2$ value was 0.65 and the Nash-Sutcliffe coefficient value was 0.60 when no slope adjustment was made in CN method. However, the $R^2$ value was 0.69 and the Nash-Sutcliffe value was 0.69 with slope adjustment. As shown in this study, it is strongly recommended the slope adjustment in the CN direct runoff estimation should be made for accurate direct runoff prediction using the CN-based L-THIA model when applied to steep mountainous areas.

• Ecology and Resilient Infrastructure
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• 제7권2호
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• pp.114-125
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• 2020

본 연구는 유출모형 연구를 위해 주로 사용되었던 DNN에서 벗어나, 다양한 신경망을 이용하여 유출모형을 개발하고 모형의 적합성을 나타내고자 하였다. 이를 위해 분류문제에만 사용되었던 CNN을 활용하였는데, 본 모형의 입력자료로 일반적으로 CNN에서 사용하는 사진을 이용할 수 없으며, 연구의 특성상 유역조건 및 강우 등의 영향이 반영된 수치적(numerical) 이미지(image)를 사용해야 하는 난해점이 있다. 이를 해결하고자 NRCS의 CN을 사용하여 이미지를 생성했으며, CNN 모형의 입력자료로 충분히 활용 가능함을 나타냈다. 이에 더하여, 유출 추정을 위해서만 사용되어왔던 CN의 새로운 용도를 제시할 수 있었다. 모형의 학습 및 검정 결과, 전반적으로 안정적으로 모형의 학습 및 일반화가 이루어졌으며, 관측값과 산정값간의 관계를 나타내는 R²는 0.79로 비교적 높은 값이 나타났다. 또한, 모형의 평가결과는 Pearson 상관계수, NSE, 및 RMSE 등이 각각 0.84, 0.65 및 24.54 ㎥/s으로 나타나, 전반적으로 양호한 모형의 산정성능을 보인것으로 나타났다.

• 한국수자원학회논문집
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• 제46권11호
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• pp.1053-1067
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• 2013

본 논문에서 소개되는 분포형 생태수문모형은 현실적으로 확보 가능한 입력자료와 최소한의 매개변수를 이용하여 유역의 수문, 식생, 지표온도를 모의하는 모형이다. 개발된 모형은 내성천 유역에 대해 적용하여 모형의 활용가능성을 살펴보았다. 우선적으로 매개변수에 대해 민감도 분석을 실시하여 모의결과에 많은 영향을 주는 매개변수를 선별해보았으며 이후 최적화 기법을 통해 모형의 매개변수를 추정하여 내성천 유역의 최근 10년간(2001~2010)의 수문, 식생, 지표온도 그리고 추적(routing)을 통한 하천유량 및 하천수온을 모의하였다. 최적화 기법을 통해 추정자료를 이용하여 매개변수를 추정하였으며 일부 격자를 제외한 대다수의 격자에서 적절히 모의된 것을 확인하였다. 하천유량 및 하천수온의 경우 단위 유역 말단 두 지점에 대해 검증을 실시하였으며 하천유량 및 하천수온 적절히 모의된 것을 확인할 수 있었다. 실제 유역인 내성천 유역을 대상으로 분포형 생태수문모형이 최소한(현실적으로 확보 가능한)의 입력자료와 매개변수를 이용함에도 불구하고 유역 수문순환 및 식생을 적절히 설명하고 있음을 살펴볼 수 있다.