• Economic and Environmental Geology
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• v.40 no.4
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• pp.403-418
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• 2007

The objective of this research was to characterize the fate and transport of Cr(VI) contaminated groundwater in the Daejeon industrial area. Five subsidiary monitoring wells were newly installed and two existing wells were utilized for the investigation and the reduction process of Cr(VI) contaminated groundwater of the Daejeon(Mun-pyeong) national groundwater monitoring station. The Cr(VI) concentrations at the shallow aquifer well of the station were in the range of 3.2-4.5 mg/L indicating continuous contamination. However, Cr was not detected at the deep bedrock well and the other monitoring wells except MPH-1 and 3. The Cr(VI) concentrations of MPH-1 and MPH-3 were below the drinking water guideline value (0.05 mg/L). Therefore, the plume of the Cr(VI) contaminated groundwater was predicted to be confined within the narrow boundary around the station. The soluble/exchangeable Cr(VI) concentrations were below the detection limit in all core and slime samples taken from the five newly installed wells. Although the exact source of contamination was not directly detected in the study area, the spatial Cr(VI) distribution in groundwater and characteristics of the core samples indicated that the source and the dispersion range were confined within the 100 m area from the monitoring station. The contamination might be induced from the unlined landfill of industrial wastes which was observed during the installation of an subsidiary monitoring well. For the evaluation of the natural attenuation of Cr(VI), available reduction capacities of Cr(VI) with an initial concentration of 5 mg/L were measured in soil and aquifer materials. Dark-gray clay layer samples have high capacities of Cr(VI) reduction ranging from 58 to 64%, which is obviously related to organic carbon contents of the samples. The analysis of reduction capacities implied that the soil and aquifer materials controlled the dispersion of Cr(VI) contamination in this area. However, some possibilities of dispersion by the preferential flow cannot be excluded due to the limited numbers of monitoring wells. We suggest the removal of Cr(VI) contaminated groundwater by periodical pumping, and the continuous groundwater quality monitoring for evaluation of the Cr(VI) dispersion should be followed in the study area.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1996-2000
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• 2010

국내 시설원예 면적은 2005년 기준 52,022ha에 달하고 있으며 약 23%에 해당하는 12,000ha는 겨울철에 난방기를 가동하여 원예작물을 생산하고 있다. 농업용 난방기의 보급은 가온재배 면적의 증가와 더불어 급신장하고 있어 농업용 면세유 중 경유 공급액 약 9,260억원 중 62%에 해당하는 1,350,000톤이 시설원예 난방에 사용된 것으로 추산되고 있다. 지속적인 유가 상승으로 시설재배 농가의 경영이 악화되고 있어 최근 히트펌프를 이용한 냉난방시스템에 대한 연구가 수행되고 있다. 시설원예 냉난방에 사용되는 히트펌프의 열원은 다양하게 적용할 수 있으나 강변에 위치하고 있는 시설원예단지의 경우 연 중 풍부한 유량과 안정적인 수온을 얻을 수 있는 강변여과수는 매우 매력적인 열원이다. 본 연구에서는 시범지역으로 남강댐 하류에 위치하고 있는 진주지역의 시설원예단지와 낙동강 유역의 구미지역 시설원예단지의 두 곳에 대하여 1일 $1,000m^3$의 강변여과수 개발에 대한 조사를 수행하였다. 육안 및 현장여건에 대한 조사를 수행하고 인근 지하수 사용현황에 대한 조사를 실시하였다. 진주지역의 경우 일부 농가에서 지하수를 사용하고 있었으나 1일 8~10시간 취수에 최대 취수량은 약 $120m^3$ 정도였다. 반면, 구미지역의 경우 1999년 구미첨단원예농단 조성사업의 일환으로 양액재배에 농업용수를 공급할 목적으로 지하수 개발이 실시되었으며 최근 인근 국화축제를 개최하는 지역에서 신규로 지하수를 개발하여 사용 중이었다. 전기비저항 탐사를 실시한 결과 진주지역은 지하 약 6~17m 지점에 대수층이 존재하는 것으로 판단되었고, 구미지역은 지하 약 10~20m 지점에 대수층이 존재할 가능성이 있지만 지하 20m 지점부터는 대수층의 가능성이 높은 것으로 판단되었다. 두 지역에 각각 두 공을 시추하여 조사한 결과, 구미지역의 경우 수면높이가 지하 약 10m이고 각각 2.5m와 4.6m의 모래자갈층을 형성하고 있어 $1,000m^3$/일의 취수량 개발이 원활하지 않을 것으로 판단되었다. 한편, 진주지역은 수면높이가 지하 약 3m이고 각각 3.5m와 6.5m의 모래자갈층을 형성하고 있어 $1,000m^3$/일의 취수량 개발이 가능할 것으로 판단되었다. 현장 시추조사 및 기존관정 조사결과, 구미지역에 비하여 진주지역이 지하수 물량 확보가 상대적으로 용이하고 신규 굴착 가능지점이 다수 분포하고 있어 연구지점으로 활용하는데 유리할 것으로 판단되었다. 따라서 진주지역에 여과수열원 확보를 위해 2곳의 양수관정을 설치하고 히트펌프를 이용하여 시설원예의 냉난방을 실시할 예정이다.

• Journal of Korean Society of Forest Science
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• v.112 no.2
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• pp.173-187
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• 2023

The forest protection policies implemented in South Korea have resulted in the significant accumulation of forest. Moreover, the associated public interest has also been closely evaluated. As forests mature, there arises a need for forest management (FM) practices, such as thinning and harvesting. It is therefore essential to perform a scientific analysis of the long-term effects of FM. In this study, conducted in Mt. Gariwang, the effect of FM on forest succession and wood production (WP) were evaluated based on changes in aboveground biomass (AGB) using the LANDIS-II model. The FM consists of three scenarios (Selection, Shelterwood, and Two-stories), characterized based on the harvest intensity, frequency, and period. The model was applied to changes in the forest over 200 years. All scenarios show that the total AGB decreased immediately after thinning and harvesting. However, AGB recovery time differed among scenarios, with recovery to preharvest level occurring from 15 to 50 years after harvest; further, after 200 years, harvested forests had a greater total AGB than forests without FMs In particular, the changes in AGB of each species was different depending on its shade tolerance. The AGB of currently dominant shade-intolerant and mid-tolerant species decreased dramatically after harvesting. However, shade-tolerant species, dominant in the understory, continued to grow but were not harvested due to their small size. The cumulative WP for each scenario was estimated at 545.6, 141.6, and 299.9 tons/ha in Selection, Shelterwood, and Two-stories, respectively. The composition of WP differed according to harvest intensity and period. Most WP originated from shade-intolerant and mid-tolerant species in the early period. Later, most WP was from shade-tolerant species, which became dominant. The modeling approach used in this study is capable of analyzing the long-term effects of FM on changes in forests and WP. This study can contribute to decision making to guide FM methods for a variety of purposes, including WP and controlling forest composition and structure.