공학양 Hak Yang Kong , 김세미 Semi Kim , 이재윤 Jaeyoon Lee , 이재안 Jae An Lee , 조형진 Hyungjin Cho

DOI:10.15681/KSWE.2016.32.2.135 Vol.32(No.2) 135-141, 2016

This study investigated changes of hydrology, soil characteristics, riparian vegetation communities, and geomorphology in sandbars before and after sand-mining to determine the effect of sand-mining at upstream of Guemgang and Bochungcheon streams in Korea. Sand-mining events affected the mining area. They supplied organic matters and nutrients during flood. Sediment deposition caused soil texture change and expansion of vegetation area. However, riverbeds were stabilized after the disturbance. According to the analyses of aerial photographs, the vegetation area was significantly expanded in both dam-regulated streams and dam-unregulated streams after sand-mining. Willow shrubs advanced in disturbed area at an average of 10 years after sand-mining. It took willows trees 10.6 years to become dominant communities. Therefore, it took a total of 20.6 years for new riparian forest to form in sandbar after sand-mining. Our results confirmed that stream flow condition were dependent on vegetation recruitment in dam-regulated streams and dam-unregulated streams. For willow recruitment in unregulated streams, calculation of water level below dimensionless bed shear stress is important because low water level variation is a limiting factor of vegetation recruitment.

Dam, Sandbar, Sand-mining, Vegetation Immigration, Vegetation recruitment, Willow

강동한 Dong Han Kang , 라자우말사자드 Umer Sajjad Raja , 김극태 Keuktae Kim , 이창희 Chang Hee Lee

DOI:10.15681/KSWE.2016.32.2.142 Vol.32(No.2) 142-148, 2016

The characterization of stormwater runoff from mix land-use catchments with an inadequate sewer network is a challenge. This study focused on characterizing stormwater runoff from the Paldang watershed area based on land-use type and sewer system coverage. A total of 76 sites were monitored during wet weather from seven different counties within Paldang watershed. Public sewer system (PSS) was installed at 48 sites, while 28 sites had no or individual sewer system (ISS) coverage. The results indicated that the sites included in the ISS group with higher forest and paddy land-use percentage exhibit higher values of average event mean concentrations (EMCs) and first flush intensity for suspended solids (SS), total nitrogen (TN), and total phosphorous (TP). In addition, upgrading runoff interception system can capture 59 % of the TP load in the first 43% of runoff within these sites. Similarly, rainfall depth and storm duration showed a positive correlation (R > 0.6) with nutrient loads within ISS group sites, as compared to PSS group. Therefore, these sites are likely to contribute higher TP and TN loads during heavier storm events and should be selected as priority management areas to combat the problem of eutrophication in Paldang reservoir.

Eutrophication, Land-use, Sewer system, Stormwater runoff

김태구 Taegoo Kim , 유종원 Jongwon Yoo , 조형익 Hyung Ik Cho , 한정호 Jeongho Han , 이동준 Dong Jun Lee , 정영훈 Younghun Jung , 양재의 Jae E Yang , 임경재 Kyoung Jae Lim

DOI:10.15681/KSWE.2016.32.2.149 Vol.32(No.2) 149-162, 2016

In recent years, there has been demand for precise estimations of pollutant loads on nationwide scale for the development of appropriate site specific (watershed specific) policies to reduce the negative impact of pollutant loads. River flow data and water quality data that were previously collected by various research institutes and universities for specific research purposes for a limited period was utilized in this study. However, only TMDL 8-day interval flow and water quality data were available in national scale. Three watersheds were selected and pollutant loads were calculated by two methods i.e., Numeric Integration (NI) method and Soil and Water Assessment Tool (SWAT). Subsequently, the results were compared to determine the appropriate method for monitoring nonpoint source networks nationwide. The SWAT model was calibrated and its estimated daily flow data were used in the NI method with estimated sediment data for 8-day monitoring data for three watersheds. The results indicated that the quantity of pollutant loads estimated with the NI and SWAT are different to some degrees especially during the summer season for all the three study watersheds. Thus, more frequent sampling of water quality is needed for nonpoint source pollutant estimation.

NI method, Nonpoint source pollution, Pollutant load, SWAT model

박상현 Sanghyun Park , 김홍수 Hongsu Kim , 조병욱 Byunguk Cho , 문은호 Eunho Moon , 최진하 Jinha Choi

DOI:10.15681/KSWE.2016.32.2.163 Vol.32(No.2) 163-172, 2016

This study aimed to develop a plan for effective performance of a watershed through correct identification of a river watershed by using the flowrate of the river and water quality data, which is the basis for the establishment of the water environment policy. The target river for water quality improvement was selected based on the monitoring result for 4 water systems in Chungcheongnamdo province in the recent 3 years. The result of analysis for the distribution of discharge capacity by a pollution source group for the water quality improvement target river showed that most of the target river has a high discharge capacity in the water system for living and livestock. Analysis for the density of the total discharge capacity of the whole watershed of Chungcheongnamdo indicated that the river that needs water quality improvement has high BOD concentration and high discharge load density at the point that this river is located. Thus, for efficient watershed management through selection and concentration, Chungcheongnamdo needs to improve the target river in priority. Stepwise planning is also required to establish and execute the water quality improvement in order to satisfy said target water quality, and establish the index for the water improvement rate for its evaluation.

Discharge capacity, Discharge load density, Monitoring, Target river in priority, Water quality rating

이혜숙 Hye Suk Yi , 김동섭 Dong Sup Kim , 황만하 Man Ha Hwang , 안광국 Kwang Guk An

DOI:10.15681/KSWE.2016.32.2.173 Vol.32(No.2) 173-182, 2016

The objective of this study is to quantitatively analyze climate change effects by using statistical trends and a watershed model in the Yongdam dam watershed. The annual average air temperature was found to increase with statistical significance. In particular, greater increases were observed in autumn. Also, this study was performed to evaluate the potential climate change in the streamflow and water temperature using a watershed model (HSPF) with RCP climate change scenarios. The streamflow of Geum river showed a decrease of 5.1% and 0.2%, respectively, in the baseline data for the 2040s and 2080s. The seasonal impact of future climate change on the streamflow showed a decrease in the summer and an increase in the winter. The water temperature of Geum river showed an average increase of 0.7~1.0℃. Especially, the water temperature of Geum river showed an increase of 0.3~0.5℃ in the 2040s and 0.5~1.2℃ in the 2080s. The seasonal impact of future climate change on the water temperature showed an increase in winter and spring, with a decrease in summer. Therefore, it was determined that a statistical analysis-based meteorological and quantitative forecast of streamflow and water temperature using a watershed model is necessary to assess climate change impact and to establish plans for future water resource management.

Climate change, HSPF, RCP Scenario, Statistical analysis, Yongdam dam watershed

서지연 Jiyeon Seo , 박배경 Baekyung Park , 박운지 Woonji Park , 윤광식 Kwangsik Yoon , 최동호 Dongho Choi , 김용석 Yongseok Kim , 류지철 Jichul Ryu , 최중대 Joongdae Choi

DOI:10.15681/KSWE.2016.32.2.183 Vol.32(No.2) 183-190, 2016

Monitored data (rainfall runoff and water quality) from 4 different paddy sites over 3 years were compared to analyze the effect of irrigation water management on irrigation supply and rainfall runoff quality in Korea. The system of rice intensification water management was adopted at one site (SRI) while the conventional water management method was used for rice culture at the other three sites (CT, SD and HD). The soil texture at SRI, CT and SD was sandy loam while that at HD was silt loam. The average reduction of irrigation supply at SRI compared with CT, SD and HD during the 3 years studied was 49%, 51% and 55%, respectively. The average event mean concentration (EMC) at SRI compared with that at CT, SD and HD was decreased by 35% (BOD), 44% (COD), 47% (SS), 19% (TN) and 38% (TP). The correlation between rainfall runoff and the measured non-point source (NPS) pollutants was very good in general. The comparison revealed that SRI water management significantly reduced both irrigation supply and EMC in rainfall runoff. Paddy NPS pollution was closely related to factors that induce runoff such as rainfall and irrigation supply. It was concluded that SRI management could be an effective and practical option to cope with both water shortage due to climate change and water quality improvement in rural watersheds. However, further studies are recommended in large irrigation districts for use in the development and implementation of NPS pollution policies since the data was collected from field sized paddies.

EMCs, Irrigation water reduction, NPS pollution, System of rice intensification, SRI

최유현 Yoo Hyun Choi , 엄한기 Han Ki Eom , 김성철 Sung Chul Kim , 주현종 Hyun Jong Joo

DOI:10.15681/KSWE.2016.32.2.191 Vol.32(No.2) 191-196, 2016

This study aimed to evaluate SBR operation cycle for removing the high-concentration organic matter of distillery wastewater in the ginseng processing plant. The experiment was conducted with the use of a laboratory scale SBR reactor and distillery wastewater as the influent. The results indicated an increase in pH from 4.08 to 7.59 of distillery wastewater after aeration for 2 hours. Also, the optimum SBR operation cycle for the removal of organic matter and nitrogen was 2 hr of aeration and 6 hr of anaerobic conditions. Adjustment of proper pH through aeration time is most critical in the SBR operation for distillery wastewater treatment. In this study, we presented an efficient method for distillery wastewater treatment.

Distillery wastewater, Operation cycle, pH change, SBR

최희정 Hee Jeong Choi , 이정민 Jung Min Lee

DOI:10.15681/KSWE.2016.32.2.197 Vol.32(No.2) 197-204, 2016

The growth of the algae strain Chlorella vulgaris under mixotrophic conditions in the presence of saccharified acorn-starch (acorn-glucose) was evaluated with the objective of increasing biomass growth and triacylglycerols (TAGs) content. The results indicated that 81.3% of starch was converted to glucose in acorns. C.vulgaris algal strains grown with acorn-glucose produced higher biomass and TAGs content than with autotrophic growth. The highest biomass production and TAGs content with 3 g/L acorn-glucose were 12.44 g/L and 32.9%, respectively. Biomass production with 3 g/L acorn-glucose was 16.4 fold higher than under autotrophic growth condition. These findings suggested that 3 g/L acorn-glucose is economic and efficient for biomass production/productivity and TAGs content of microalgae. This study provides a feasible way to reduce the cost of bioenergy production from microalgae.

Acorn-starch, Biomass, Glucose, Microalgae, Mixotrophic, Oil content

안지홍 Ji Hong An , 임치홍 Chi Hong Lim , 임윤경 Yun Kyung Lim , 남경배 Kyeong Bae Nam , 피정훈 Jung Hun Pi , 문정숙 Jeong Sook Moon , 방제용 Je Yong Bang , 이창석 Chang Seok Lee

DOI:10.15681/KSWE.2016.32.2.205 Vol.32(No.2) 205-215, 2016

In order to improve water quality in the Paldang Lake, a riparian vegetation belt, treatment wetland, and artificial floating island were designed for introduction in the upland field, the estuary of tributaries, and the section of water facing mountainous land, respectively. We synthesized vegetation information collected from a reference river and found that herbaceous, shrubby, and tree vegetation zones tended to be dominated by Phragmites japonica, Phalaris arundinacea, etc.; Salix gracilistyla, S. integra, etc.; and S. koreensis, S. subfragilis, and Morus alba, respectively. In our plan, the herbaceous vegetation zone, which is established on floodplains with a high frequency of disturbance, will be left in its natural state. A shrubby vegetation zone will be created by imitating the species composition of the reference river in the ecotone between floodplain and embankment. A tree vegetation zone will be created by imitating species composition on the embankment slope. In the treatment wetland, we plan to create emerged and softwood plant zones by imitating the species composition of the Zizania latifolia community, the Typha orientalis community, the P. communis community, the S. integra community, and the S. koreensis community. The floating island will be created by restoring Z. latifolia and T. orientalis for water purification purposes.

Artificial floating island, Reference river, Riparian vegetation belt, Treatment wetland

신우석 Woo Seok Shin , 나규리 Kyu Ri Na , 김영기 Young Kee Kim

DOI:10.15681/KSWE.2016.32.2.216 Vol.32(No.2) 216-221, 2016

The adsorption characteristics of mixed heavy metals (Cr(III), As(VI)) in aqueous solution were investigated using a sediment amendment composite. Sediment amendment composite was composed of clean sediment (40%), zeolite (20%), recycled aggregate (10%), steel slag (10%), oyster shell (10%), and cement (10%). The experimental results showed that the adsorption equilibrium was attained after 180 mins. Heavy metal adsorption was characterized using Freundlich and Langmuir equations. The equilibrium adsorption data for the sediment amendment composite better fitted with the Langmuir model than the Freundlich model. The maximum adsorption capacity of Cr(VI) (36.07 mg/g) was higher than As(III) (25.54 mg/g); and the adsorption efficiency of the Cr(VI) and As(III) ions solution decreased with decreasing pH from 2 to 10. The collective results suggested that the sediment amendment composite is a promising material for a reactive cap that controls the release of Cr(VI) and As(III) from contaminated sediments.

Adsorption, Capping material, Heavy metals, Industrial by-products, Natural mineral