• Journal of Environmental Impact Assessment
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• v.28 no.6
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• pp.536-548
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• 2019

In order to quantify the effect of the newly established the Total Water Load Management System in Sapgyo watershed, this study predicted the achievement of the target water quality at each unit watershed and the water quality according to the flow section. The HSPF model, which is the watershed runoff model, was constructed and operated based on 2015, and the water quality was predicted by inputting the loads in final target year(2030). The Load Duration Curve (LDC) was created using the simulated results of base year and target year. As a result of plotting water quality by flow conditions, it was simulated to be close to the BOD target with a difference of 0.1 ~ 0.2 mg/L in all three watersheds during the mid-range flow interval (40 ~ 60%). In case of T-P, although the target water quality was not set, the water quality was improved by Cheonan A 46%, Kokgyo A 29% and Namwon A 25%. The Muhan and Sapgyo river basins meet the target grade of middle-watershed standards. The improvement effect will be positive, as water quality, which achieves the target of Total Load Management System and the target grade of the middle-watershed standards will be expected to flow into the Sapgyo lake.

• Journal of Korea Water Resources Association
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• v.52 no.spc2
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• pp.777-789
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• 2019

The purpose of this study is to evaluate changes in water quality and aquatic ecosystem health by additional dam release of stream maintenance flow from multipurpose dams in Han river basin ($34,148km^2$) using SWAT (Soil and Water Assessment Tool). The period of additional release was spring (April to June) and autumn (August to October) to evaluate the changes with the data of aquatic ecosystem health survey. The amount of additional release was set proportional to the present dam release, and the maximum release amount was controlled not to exceed the officially notified stream maintenance flow from dam. The 10 percent to 50 percent additional releases showed that the stream water quality (T-N, $NH_4$, T-P, and $PO_4-P$) concentrations except $NO_3-N$ decreased in spring while increased in autumn period. Using the stream water quality results and applying with Random Forest algorithm, the grade of aquatic ecosystem health index (FAI, TDI, and BMI) was improved for both periods especially in the downstream of basin. This study showed that the additional release of stream maintenance flow was more effective in spring than autumn period for the improvement of water quality and aquatic ecosystem.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.4
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• pp.519-525
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• 2011

We studied on the effect of faucet cleanliness, faucet conditions (screen, mixing faucet), and flushing time for bacterial detection in tap water. As results, tap water should be left to run to waste for 2 to 3 minutes and if a questionable cleanliness is questionable, disinfect the faucet by using flaming or other methods before sampling. We proposed sampling method to decrease effect of factors associated with bacterial detection in tap water and contributed to be evaluated more accurate water quality.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.737-740
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• 2008

This study, with the purpose for early quality improvement of concrete which used large quantity of fly ash, changed various admixture material type and reviewed the basic characteristics. First off, the flow overall was highest when polycarb onic Acid high early strength AE water reducing agent was displaced, while air amount satisfied target level only in the case of plain, and setting time was shown best by getting 30 more minutes than plain and about 3 more hours than conventional when KOH is displaced. Compressive strength was shown best at age 1 day and 3 days when KOH was displaced, and at age 28 days when fine particle cement was displaced. By and large, this study concludes that concrete quality improvement admixture material that used large amount of fly ash showed worse effects than plain, therefore it is determined that there need be more study for development of concrete early quality improvement admixture material that used large amount of fly ash.

• Journal of Environmental Policy
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• v.1 no.1
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• pp.47-74
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• 2002

본 연구에서는 낙동강 하구의 대포천에서의 주민운동을 분석하여 지역사회가 주도하는 환경운동이 특정 조건이 충족된다면 성공적인 환경관리를 할 수 있는 대안이 될 수 있음을 보여준다. 지역사회기반 환경보호(Community-Based Environmental Protection)는 다양한 명칭으로 표현되고 있으나 지역주민의 주도 하에서 환경보호 및 개선을 이룩하는 것으로 지속가능한 사회를 달성할 수 있는 유용한 환경관리 방안으로 이론적인 지지를 받고 있다. 이 방법은 정부의 강압적인 규제보다 효과적일 수 있으며 지역사회의 다양한 욕구와 환경문제를 동시에 고려하게 되는 장점도 있다. 그러나 이러한 지역기반환경운동이 실재 전개되어 성공하는 경우는 흔하지 않다. 그런데 낙동강 하류의 대포천 사례는 지역주민의 환경규제반대운동이 결국에는 주민의 자발적인 수질개선운동으로 발전하여 실질적인 수질개선효과를 창출하였다. 뿐만 아니라 낙동강특별법의 제정 시에 제도화되어 수질환경정책의 발전에도 기여한 특별한 사례이다. 본 연구는 대포천 사례를 우리나라 수질관리정책의 종합적인 체계와 연계시켜서 살펴보면서 대포천 인근지역주민의 수질개선운동의 단계적 전개과정을 살펴보고 이 운동이 성공할 수 있었던 요인을 분석하고 있다.

• Journal of Korean Society on Water Environment
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• v.24 no.4
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• pp.415-422
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• 2008

Drinking water treatment is enhanced by coagulant dosages and chlorine injection because of pH increase in raw water in droughty seasons such as spring and fall. But water quality deterioration is occurred by increase in residual aluminium and disinfection by-products. Coagulation process can be used to control natural organic matter (NOM) during water treatment. The effect of coagulation process appeared to depend on the pH of water rather than coagulant dosages. In this study, for water treatment in high pH season $H_2SO_4$ was applied for pH adjustment at full scale. Before and after pH adjustment by $H_2SO_4$ injection, water quality of drinking water was evaluate. In the result of investigation of total organic carbon (TOC) removal in high pH season, TOC was removed approximately 30~40%, which showed decrease in water treatment efficiency. Also, it is increased both particle numbers and residual Al concentration in the water. After $H_2SO_4$ injection for adjustment to pH<7.5 in settled water, treated water turbidity decreased in 0.047 NTU from 0.059 NTU, and particle numbers of filtered water decreased in 20/mL from 90/mL. On the other side, TOC removal efficiency increased in approximately 10% after adjustment of pH. In the result of decrease in pH in raw water through more coagulants and prechlorine without $H_2SO_4$ injection, trihalomethanes (THMs) concentration increased in $16{\mu}g/L$ from $8{\mu}g/L$.

• Journal of Environmental Impact Assessment
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• v.10 no.3
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• pp.245-255
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• 2001

The management of water, both the quantity and the quality, has been one of the most important issues in the public investment and it is equally true in the field of sustainable development. Nevertheless, the jurisdiction of local governments has been delineated without much attention to the issue of the water management. In the planning of wide areas such as cities, countries, the metropolis, and the megalopolis, it is necessary to well arrange the geographical jurisdiction of local governments as a unit of region. The river water system, including small streams to large rivers, should be given its due share in the planning and jurisdictional delineation. The traditional concept of the local government's jurisdiction emphasizing the accessibility may be fading away. Instead, the efficiency of the public management would be the main concept in determining the jurisdiction of local governments. The river improvement, the waterworks, the sewage, the maintenance of water quality, the space of water recreation, are relatively important in the efficient management of that area. This paper argues for the equalization between the geographical jurisdiction of local governments and watersheds. To this end, I do case studies of the local governments areas such as Ri(里), Eup Myon(邑 面), Si Gun(市 郡), KyangyokSi Do(廣域市 道). The study interprets ARS will be one of the principles of land use and the reorganization of the local jurisdiction in the future as a geo-systematic and the eco-systematic criteria.

• Journal of the Korean Institute of Landscape Architecture
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• v.26 no.2
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• pp.101-109
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• 1998

Recently, improvement of the quality of urban riverscape environment has been emphasized not only by landscape architectural field but also by various professionals in planning and ecology. Regarding to this current movement, the aim of this paper is to highlight major visual elements of riverscape axis as a case study of Shinchon River in Taegu City to suggest some basic guidelines for arranging riverscape in urban area. The study was mainly based on Repertory Grid Development method which was developed in Japan. The method is consist of three steps such as decision of element landscape in study area for slide photos, selection of evaluation items for interview and obstraction of proper evaluation factors. The major findings through this study are as follows; 1) The 12 major visual elements which possibly improve riverscape, based on abstraction of proper evaluation factors, are Dunchi, surface of the water,, equipment of river, buildings near riverside, river vertical and horizontal facilities like bridge, fine view, riverbed, water plant, naturalness, water's edge line, harmony and street trees by order. 2) Total numbers of adjective which describe 12 common factors are 25, such as clean, open, stable, quiet, comfortable, friendly, bright, natural etc. In addition, Dunchi was described 337 times by various adjectives, surface of the water was 200 times and arrangement of river was 146 times which is similar result with the order of 12 influential common factors. 3) Therefore, Dunchi, surface of the water and equipment of river are three most important factors which could create better riverscape. These three factors implies us how we supply good quality of urban river environment for the urban residents.

• Korean Journal of Environmental Agriculture
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• v.20 no.3
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• pp.143-149
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• 2001

A contact oxidation canal system with sedimentation basin was installed to study the efficiency of water quality purification. The primary sedimentation basin with 60 min of HRT (Hydraulic Retention Time) included in the system was aimed to sediment pollutants in the water and the deposit being released by the drainage culvert located at the bottom of the system. The oxidation canal aerated by nozzle was to contact the pollutants and oxygen in the surface of plastic filter to purify the water. Discharge, HRT, length of the oxidation canal were $200\;m^3/day$, 90 min, 20 m, respectively. The treatment efficiency of total nitrogen was lower compared with other water quality items such as SS, BOD, TP because the anoxic condition for denitrification was not ensured after the oxidation canal. However, $25%{\sim}89.6%$ of SS, $75.0%{\sim}91.5%$ of BOD, $44.3%{\sim}95.3%$ of TP were removed in this system. Overall, the results indicates that this system appears to have a potential capability for water quality improvement of the reservoirs or the canals in the agricultural watershed.

• Journal of Environmental Impact Assessment
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• v.12 no.5
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• pp.359-367
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• 2003

The total pollution load management system of watershed has been implemented upon Special Law pertaining to the Han River Watershed Water Quality Improvement and Residents Support, Special Law pertaining to the Nakdong River Watershed Water Management and Residents Support, Special Law pertaining to the Youngsan River Watershed Water Management and Residents Support, and Special Law pertaining to the Seomjin River Watershed Water Management and Residents Support in Korea since 2002. But many other similar systems with total pollution load management system of watershed are being operated separately or independently, even though its purpose is nearly same with those of the total maximum pollutants load management in Law on Water Quality Environmental Protection, environmental impact assessment(EIA) in Law of Impact Assessment on Environment, Transportation and Disaster and Pre-environmental assessment of Environmental Policy Act. Therefore the contents of total pollution load management system of watershed and many other related systems could be overlapped and at some times have inconsistency among them. This study suggests first the integrated operation of total pollution load management system of watershed, EIA, pre-environmental assessment, urban planning, and sewage planning and secondly EIA system development by integration of EIA and pre-environmental assessment and strategic environmental assessment(SEA).