• Water for future
• /
• v.44 no.3
• /
• pp.24-31
• /
• 2011

본 연구는 낙동강의 4대강 살리기 사업에 의한 수질 변화를 예측하기 위하여 미국환경부에서 사용하는 3차원 수리동역학 모델 EFDC와 수질모델 WASP7을 연계 하는 방법을 택하였다. 수질모의결과, 사업에 의하여 전반적으로 BOD5 농도는 다소 감소하고 TN과 TP 농도는 거의 유사한 수준을 나타내었다. BOD5 농도의 감소는 체류시간이 증가함에 따라 유기물의 산화 또는 분해에 제공되는 시간이 증가되어 나타난 영향으로 분석된다. TN과 TP는 침강 또는 식물의 흡수 등에 의해 수체에서 제거되나 사업에 의해 크게 영향을 받지 않은 것으로 분석되었다. Chl-a 농도는 금호강이 유입되기 전 상류에서는 사업에 의해 심각한 수준으로 증가하는 것으로 분석되었으나, 금호강 유입 이후 이러한 증가 경향은 상당 부분 둔화되는 것으로 나타났으며 낙동강 하구언부근에서는 사업으로 인하여 Chl-a 농도가 감소되는 것으로 나타났다. Chl-a 농도의 변화는 TN 및 TP 농도가 사업에 의해 전반적으로 크게 차이가 나지 않음에 따라 영양염류의 농도변화에 의한 영향은 크게 작용하지 않은 것으로 판단되며, 보 건설에 의한 체류시간의 증가와 준설 또는 수심의 증가에 따른 광량의 감소가 복합적으로 작용한 결과에 의한 것으로 분석된다.

• Korean Journal of Plant Resources
• /
• v.19 no.5
• /
• pp.598-601
• /
• 2006

In order to prevent chestnut from damaged by the chestnut gall wasp, Dryocosmus kuriphilus, a sprinkler system was installed on the chestnut orchard. Such a test was conducted at Sanchung-gun, Kyeongnam province, Korea in 2003 and 2004. Insecticide of carbaryl 50% WP, x1,500 was sprayed at every day and two-day intervals during the period of D. kuriphilus adult occurrence by sprinkler system. The chestnut gall wasps generally emerged for about 35 days from the middle June to the middle July, and peak emergence was 5 days of early July. Crown application of carbaryl by sprinkler system was found to be highly effective for control of the chestnut gall wasp. Gall formation rate of chestnut were 3.0 and 12.8% on average with crown insecticide spraying at every day and two-day intervals, while 82.9% when not treated. Control effectiveness of this insecticide spraying was 96.4% and 84.6%, respectively.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.9 no.3
• /
• pp.771-778
• /
• 2008

Effects of establishments of more sewer systems on water quality in Nam River, Deokchun River, and Jinyang Lake were analyzed for various scenarios using QUAL2E, WASP 7 water quality model. Three different scenarios were tested: 1) 20.8% of sewer diffusion rate which is same to the existing condition. 2) Expansion of sewer system to 65.2% which would emit less pollutants, BOD 2350.5 kg/d, TN 216.0 kg/d, TP 44.0kg/d. 3) Pollutants emission to maintain first grade water quality in Nam River, Jinyang Lake, BOD and TN in the case 2 were 7.69%, 2.10% lower than those in the case 1 in the Nam River. And in the Jinyang Lake, BOD, TN, and TP in the case 2 were 10.25%, 1.37%, 2.94% lower than those in the case 1. However the simulations showed that water quality could not hold down first grade water quality standard level with the establishments of more sewer systems. To satisfy the criteria in the Nam River and Jinyang Lake, BOD emission must be reduced 27.2%, 37.05% compared to those in the case 1.

• Journal of Korean Society of Forest Science
• /
• v.32 no.1
• /
• pp.21-28
• /
• 1976

This paper reports on seasonal variation of tannin, catechol tannin, pyrogallol tannin, sugar, starch and protein contained in new shoots of four races of Castanea crenata in relation to their resistance to gall-wasps. The four races were Ginyose, Shimokatsugi, Taisyo-wase and Tsuguba. 1. Tannin contents showed the lowest level during June and September, and they gradually increased afterwards. Generally tannin contents were higher in gall-wasp resistant races than in its susceptible races. Mean annual tannin contents were 0.73%, 0.845%, 0.507%, and 0.520%, respectively, in Tsuguba, Ginyose, Shimokatsugi and Taisyo-wase. 2. Catechol tannin contents did not change from February to October, however, increased after that period. Catechol tannin contents in gall-wasp resistant races (Tsuguba and Ginyose) more than doubled those in the susceptible races (Shimokatsugi and Taisyo-wase) all the year round, indicating that there may be a correlation between quantitative differences in catechol tannin and the resistance to gall-wasps. 3. Pyrogallol tannin contents were rather lower in the gall-wasp resistant races than in the susceptible races on the contrary to the above results. 4. Seasonal variation of sugar contents showed similar tendency with catechol tannin. Gall-wasp resistant races contained higher sugar contents than those susceptible races. 5. Starch contents were significantly higher during dormant period. Gall-wasp susceptible races showed higher starch contents than the resistant races did, however, this tendency varied with season. 6. There were not significant differences in protein between races but there was a tendency of higher protein in gall-wasp susceptible races. The seasonal change of protein was similar to that of starch. 7. From the above results it seems that seasonal variation of contents of tannin, catechol and pyrogallol tannin, sugar, starch and protein in new shoots of chestnut trees have some relation to their resistance to gall-wasp.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.12
• /
• pp.1265-1273
• /
• 2006

The environmental capacity and watershed pollution load reduction of Yongdam reservoir were estimated by the simulation of water quality variation process with the target water quality establishment, pollution load estimation and flow analysis. The potable raw water $I{\sim}II$, COD $1.0{\sim}3.0$ mg/L and TP $0.01{\sim}0.03$ mg/L were selected as the target water quality Yongdam reservoir water quality model was constructed with WASP5 contained 42 segments and the correlation of calibrated results were BOD 0.73, $PO_4-P$ 0.98. The environmental capacity for target quality COD 2.0 mg/L and TP 0.02 mg/L were BOD $131,880{\sim}4,694$ kg/d, TP $7,855 {\sim}167$ kg/d which were less than exists, and the related reduction ratios were BOD $51{\sim}62%$, TP $47{\sim}67%$ which were middle amount in exists. The load reduction ratios to meet the potable raw water $I{\sim}II$ were BOD $72{\sim}16%$, TP $78{\sim}36%$ in existing conditions and BOD $81{\sim}44%$, TP $84{\sim}52%$ in new conditions. BOD was the least one and TP was the second least in 4 results. The effects of the load reduction assignment to subbasin were dominant in TP but little in COD.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.15 no.11
• /
• pp.6943-6951
• /
• 2014

The trophic state assessment of the Hwoiya reservoir was estimated using the Trophic state indices (TSIs) of Carlson and Aizaki using the transparency and concentrations of chlorophyll-a and total phosphorus obtained from two sites of the reservoir. The TSIs assessments showed that eutrophic phenomena occur frequently in the Hwoiya reservoir. In addition, strategies to reduce the phosphorus especially would be prepared because the Hwoiya reservoir exceeded phosphorus-limiting state of 17 < TN/TP (total nitrogen/total phosphorus). Three scenarios for a simulation of the dredging effect of sediments on the water quality using the WASP7 model were made at two sites, which were 10% (scenario 1), 40% (scenario 2) and 60% elution of the pollutants from sediments (scenario 3). In the most elution case (60%), scenario 3, it was considered that 6.4% TN and 9.3% TP at site 1, and 3.9% TN and 5.6% TP at site 2 could be reduced.

• Journal of Environmental Science International
• /
• v.25 no.8
• /
• pp.1191-1206
• /
• 2016

Transported deposit was accumulated in a grit chamber built at the mouth of Yeocheoncheon in 1987 with the intention of blocking the influx of sediment into the Ulsan-harbor. This study attempted to analyze the effects of the transported deposit on the water quality at Yeocheoncheon. Only one episode of dredging has been performed in the approximately 25 years since the grit chamber were built, leading to the formation of stagnant water in the grit chamber due to a large amount of transported deposit. The deposit has a relatively high organic content, in the range of 11.7-25.9% (mean 18.3%). It appears that the main reason for the upstream transport of water pollution from the mouth of the Yeocheoncheon is the tides. The effects of organic content and stagnant water on water quality were analyzed using WASP. Moreover, the changes in water quality arising due to the removal of the grit chamber were analyzed. Results indicated that BOD improved by 18.8-100%, while T-P improved by 90.0-617.4%, between the grit chamber and Hanbi-Gyo, which is located 1.3 km away from the grit chamber.

• Journal of Energy Engineering
• /
• v.7 no.1
• /
• pp.131-137
• /
• 1998

This paper discusses definition, concepts, approach methods, application areas, and evaluation of avoided generation costs based on the Korea's official long-term generation expansion plan. The main objective to evaluate avoided costs of resources is to supply decision makers with the breakeven costs of the resources. For the evaluation of avoided costs based on the Korea's generation system, we consider a DSM option which has 1,000MW peak savings, load factor with 70 percents, and life-time with 25 years. The DSM resource can save the fuel spending and capacity additions of a electric utility during its life time. The capacity and fuel savings are evaluated from two different cashflows with and without the DSM option, which are supplied with on the basis of the generation system optimization model (WASP-II), independently. The breakeven kWh costs of the DSM option is projected to be 31.3 [won/kWh], which is composed of generation capacity and fuel avoided costs with 15.0[won/kWh] and 16.3[won/kWh], respectively.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2011.05a
• /
• pp.48-48
• /
• 2011

본 연구에서는 미래 기후변화가 하천 및 호소수질에 미치는 영향을 평가하고자 유역 수문-수질 모의가 가능한 SWAT(Soil and water assessment tool) 모형과 호소수질 모의가 가능한 WASP(Water Quality Simulation Program) 모형을 연계운영하여 충주호를 포함하는 충주댐 유역($6,642.0km^2$)에 적용하였다. 이를 위해 IPCC(Intergovernmental panel on climate change)에서 제공하는 A1B 배출시나리오를 포함하는 MIROC3.2 hires 모형의 결과로부터 충주댐 유역의 총 6개 기상관측소에 대한 과거 30년(1997~2006) 실측자료를 바탕으로 미래 온도와 강수에 대한 편이보정(Bias correction) 및 Change Factor Method로 상세화(Downscaling)하여 미래 기후자료(2020s, 2050s, 2080s)를 생산하였다. 미래 연평균 온도는 기준년도인 2000년에 비해 최대 $+4.8^{\circ}C$(2080s)의 온도증가를 보였으며, 강수량의 경우 여름과 가을 강수량이 다소 감소하였으나 연평균 강수량은 최대 +34.4%(2080s) 증가하는 것으로 전망되었다. 먼저, SWAT 모형을 이용한 기후변화에 따른 댐 유입량은 39.8%(2080s) 증가는 것으로 분석되었으며 유역의 유출특성 변화로 인한 유사량은 지표유출변화에 기인하여 봄과 겨울에 증가하는 경향과 함께 -14.5%(2020s) ~ +27.3%(2080s)의 변화를 보이는 것으로 분석되었다. 영양물질에 대한 오염부하량은 2080s에서 T-N이 증가추세를 보이며 최대 87.3% 까지 증가하는 반면, T-P는 유사량과 유사한 변화패턴을 보이며 최대 48.4%까지 감소하는 것으로 분석되었다. 호소수질 모델링을 위한 충주호의 Segment 구성은 충주댐1 지점에서부터 충주댐4 지점까지 전체 수표면적 $65.7km^2$에 대하여 상층과 하층 총 760개로 구성하였으며, SWAT 모형에 의한 충주호 유입하천 소유역에서의 미래 유출 및 영양물질 자료를 WASP 모형의 초기값으로 입력하여 수체 내의 BOD, Chl-a, T-N, T-P 변화 분석을 실시하였다. 이와 같이 지구 온난화에 의한 기후변화는 강우특성 변화에 따른 가뭄과 홍수 등 극한 기상현상의 발생, 유역 물순환 체계 변화를 야기 시키므로서 수자원 부존량 변화에 영향을 미칠 뿐만 아니라 기온상승에 따른 수온변화, 비점오염물질의 거동에도 변화를 초래하여 하천 및 호소 수질에 큰 영향을 미칠 것으로 판단된다.

• Journal of Wetlands Research
• /
• v.13 no.1
• /
• pp.139-148
• /
• 2011

Web structure of spiders is a foraging strategy as well as an investment to get prey. In order to make a good foraging decision spiders should change its foraging strategy in the basis of sensory information provided by potential prey species. We conducted experiments to demonstrate whether a wasp spider, Argiope bruennichi modifies its web-building behavior after experiencing sensory information emitted by a cricket species, Teleogryllus emma. To know how the web structures would be modified, we quantified web characteristics after providing sensory information of the cricket and compared to the control group. Web construction decreased in the course of the experiment in both, control group(without stimulus) and experimental group(with stimuli). The results did not show remarkable differences between two groups. However, on the first day after providing sensory information of the cricket, the web-building behavior of A. bruennichi decreased only in 3.7% of the experimental group individuals against 11.8% of the control group individuals. The number of the stabilimentum constructions decreased overall in both groups. On the first day the decreasing proportion was doubled in the control group(14.7%), comparing to the experimental group(7.4%). The individuals did not lower its web height and did not extend its web area according to sensory information of the prey.