• Journal of Environmental Impact Assessment
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• v.20 no.1
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• pp.71-78
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• 2011

This paper aims to assessing impact of reduction of non-point source pollution in the Bokha Stream watershed. The BASINS/HSPF model was calibrated and verified for water flow and water qualities using Total Maximum Daily Load 8days data from 2006 to 2007. Accuracy of the BASINS/HSPF models in simulating hydrology and water quality was compared and there were somewhat differences of statistical results, but water flow and water quality were simulated in good conditions over the study period. The applicability of models was tested to evaluate non-point source control scenarios to response hydrology and water quality in the Bokha stream using various measures which include BMPs approach and change of landuse. The evaluation of reduction of non-point source pollution was developed using load-duration curve. Despite strong reduction of non-point source, there are not satiated target quality at low flow season.

• Journal of Environmental Policy
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• v.9 no.1
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• pp.83-107
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• 2010

Urbanized environments are constructed to estimate peak flow and cost savings in response to possible BMP allocation at a watershed scale. The main goal is to explore the proper allocation of sub-watershed level BMPs for peak flow attenuation at a watershed scale. Since several individual site scale BMPs work as a form of aggregated BMPs at a sub-watershed scale, it is a question as to how to properly allocate the sub-watershed level BMPs at a watershed scale. The Hydrological Simulation Program-FORTRAN (HSPF) is set up for a hypothetically urbanized watershed. A peak flow is determined to be the primary variable of interest and targeted to characterize the spatial distribution of aggregated BMPs. Construction cost of a regional pond forms the basis of the economic valuation. The results indicate that when total size of BMPs is constant in the entire watershed, (1) it is most effective to have aggregated BMPs in some upper sub-watersheds while the BMPs in either the mainstem sub-watershed or a single sub-watershed are the least effective choices for peak flow attenuation at a watershed scale; (2) savings exist between allocation differences and reduced peak flow increases cost savings. The largest saving is found in the strategy of aggregated BMPs in some upper sub-watersheds. These findings, however, call for follow-up site specific case studies revisiting the watershed scale impacts of BMP allocation. Then, it will be argued that location and extent of decentralization are considerable policy variables for an alternative stormwater management policy at a watershed scale.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.11a
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• pp.225-229
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• 2005

The objective of this study is to evaluate snowmelt impact on watershed hydrology using climate change scenarios on Soyanggang-dam and Chungju-dam watershed. SLURP model was used for analyzing hydrological changes based on climate changes. The results (in years 2050 and 2100) of climate changes scenarios was CCCma CGCM2 of SRES suggested by IPCC and the snow cover map and snow depth was derived from NOAA/AVHRR images. The model was calibrated and verified for dam inflow data from 1998 to 2001.

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.1
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• pp.102-114
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• 2003

The objectives of the paper are to evaluate cell based pollutant loadings for different storm events, to monitor the hydrology and water quality of the Baran HP#6 watershed, and to validate AGNPS with the field data. Simplification was made to AGNPS in estimating storm erosivity factors from a triangular rainfall distribution. GIS-AGNPS interface model consists of three subsystems; the input data processor based on a geographic information system. the models. and the post processor Land use patten at the tested watershed was classified from the Landsat TM data using the artificial neural network model that adopts an error back propagation algorithm. AGNPS model parameters were obtained from the GIS databases, and additional parameters calibrated with field data. It was then tested with ungauged conditions. The simulated runoff was reasonably in good agreement as compared with the observed data. And simulated water quality parameters appear to be reasonably comparable to the field data.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.200-204
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• 2012

In engineering hydrology, an estimation of precipitation loss is one of the most important issues for successful modeling to forecast flooding or evaluate water resources for both surface and subsurface flows in a watershed. An accurate estimation of precipitation loss is required for successful implementation of rainfall-runoff models. Precipitation loss or hydrological abstraction may be defined as the portion of the precipitation that does not contribute to the direct runoff. It may consist of several loss elements or abstractions of precipitation such as infiltration, depression storage, evaporation or evapotranspiration, and interception. A composite loss rate model that combines four loss rates over time is derived as a lumped form of a continuous time function for a storm event. The composite loss rate model developed is an exponential model similar to Horton's infiltration model, but its parameters have different meanings. In this model, the initial loss rate is related to antecedent precipitation amounts prior to a storm event, and the decay factor of the loss rate is a composite decay of four losses.

• Journal of Korea Water Resources Association
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• v.30 no.5
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• pp.539-548
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• 1997

A physically based model for rainfall runoff simulation in agricultural watershed equipped with tile drains is presented. This model is developed from the TOPMODEL which is based on the detailed topographic information provided by Digital Elevation Model (DEM). Nine possible flow generation scenarios in the tile drained basin are suggested and used in the development of the model. The model can identify the portions of the hydrograph resulting from tile flow, subsurface flow and surface flow. The performance of the model is assessed through a calibration and validation process. The results of the analysis show that the model describes the physical system well and provides a better insight into the hillslope hydrology of agricultural watersheds with tile drainage.

• Proceedings of the Korea Water Resources Association Conference
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• 2003.05a
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• pp.81-88
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• 2003

In this report, we first introduce the plan of the Japanese Council of University Experimental Forests to establish Long-Term Forest Hydrological Network, and propose the cooperation between Japan Society of Hydrology and Water Resources (JSHWR) and Korean Water Resources Association (KWRA) to fulfill the plan. Then we introduce our hydrological researches conducted in a non-managed artificial forest watershed of Kyushu University Forests in 2002. Though hydrological phenomena have not sufnciently investigated, we introduce the hydrological aspects obtained in 2002 to initiate cooperative researches on Forest Ecosystems with KWRA.

• Proceedings of the Korean Society of Agricultural Engineers Conference
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• 2002.10a
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• pp.389-392
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• 2002

The objectives of the paper are to develop the total maximum daily loads simulation system, TOLOS that is capable of estimation annual nonpoint source pollution from small watersheds, to monitor the hydrology and water quality of the Balhan HP#6 watershed, and to validate TOLOS with the field data.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2005.09a
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• pp.177-180
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• 2005

• Magazine of the Korean Society of Agricultural Engineers
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• v.45 no.4
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• pp.78-88
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• 2003

The land use changes from non-urban areas to urban areas lead to the increased impervious areas, consequently increased direct runoff and higher peak runoff. Urban areas have also been recognized as significant sources of Nonpoint Source (NPS) pollution, while agricultural activities have been known as the primary sources of NPS pollution. Many features of the L-THIA/NPS GIS, L-THIA/NPS WWW system have been enhanced to provide easy-to-use system. The L-THIA model was applied to the Little Eagle Creek (LEC) watershed in Indiana to evaluate the accuracy of the model. The L-THIA/NPS GIS estimated yearly direct runoff values match the direct runoff separated from U.S. Geological Survey stream flow data reasonably. The $R^2$ and Nash-Sutcliffe values are 0.67 and 0.60, respectively. The L-THIA estimated runoff volume and total nitrogen loading for each land use classification in the LEC watershed were computed. The estimated runoff volume and total nitrogen loading in the LEC watershed increased by 180% and 270% for the 20 years. Urbanized areas -"Commercial", "High Density Residential", and "Low Density Residential"- of the LEC watershed made up around 68% of the 1991 total land areas, however contributed more than 92% of average annual runoff and 86% of total nitrogen loading. Therefore, it is essential to consider the impacts of land use change on hydrology and water quality in land use planning of urbanizing watershed.nning of urbanizing watershed.