• 농촌계획
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• 제10권1호
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• pp.19-26
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• 2004

In this paper, forestry area change effect on the soil erosion in Asan lake watershed was estimated. Temporal variations of land use in the study watershed were analyzed from Landsat-5 TM remote sensing images. Geographic Information System (GIS) combined with Universal Soil Loss Equation (USLE) was used to estimate the soil erosion of Asan lake watershed. Spatial data for each USLE factors was obtained from the Landsat-5 TM remote sensing images and 1/25,000 scale digital contour maps. Sediment yield to Asan lake was estimated by sediment delivery ratio and sediment accumulation in lake was estimated by trap efficiency. The estimation methods were validated for sediment accumulation in Asan lake. From the hydrographic survey from 1974 to 2003 for Asan lake, sediment accumulation was measured. The estimated accumulation sediment of 303,569ton/yr showed similar value with observed of 295,888ton/yr. From the validated estimation methods, the increasing amount of soil erosion when 1% of forest area in Asan lake watershed decreases was calculated from 12.91 to 1482.05ton/yr.

• 한국환경보건학회지
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• 제35권5호
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• pp.376-385
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• 2009

The characteristics of Lake Cheonhoji water and sediment were investigated in oder to utilize these as fundamental materials for the management of lake water quality. The hydrographic properties of Lake Cheonhoji which are relatively low chance of nutrients loading from the watershed and a long retention time of lake water, lead to the probability of high lake productivity. It was also observed that lake water showed stratification during summer and complete mixing during fall, even though water depth was relatively shallow. The trophic state was eutrophic to hypertrophic from summer to late fall. The overall properties of the sediment were oligohumic, high ignition loss and high composition of NAIP and Resid.-P, which might serve as potential pollution sources of lake water quality. In laboratory scale experiments, it was observed that leaching potential of nutrients in the sediment was greatly dependant upon water temperature and dissolved oxygen. Finally, water pollution in Lake Cheonhoji was considered to be largely due to the adverse cycle of uncontrollable eutrophication, which resulted in the subsequent occurrence of dead algae and animal plankton, organic sedimentation, reduction of dissolved oxygen and nutrients leaching, which again reinforced the cycle of eutrophication in the lake.

• 생태와환경
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• 제42권4호
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• pp.413-421
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• 2009

Eleven lake sediment core samples were obtained and analyzed to develop a chronology using $^{137}Cs$ (in 1963) and two tephra layers (Ko-c2 in 1694 and Ta-a in 1739). Sedimentation rates estimated for the past ca 300 years in Lake Shirarutoro indicated that catchment development has influenced the shallowing process in the lake by increasing sediment production. The sediment yield under initial land-use development conditions for the first two periods was estimated as 514 tons $yr^{-1}$ from 1694 to 1739 and 542 tons $yr^{-1}$ from 1739~1963. The development of the Shirarutoro catchment intensified in the 1960s with deforestation and agriculture activity leading to an increased sediment yield of 1261 tons $yr^{-1}$ after 1963. The sediment yields after intensified land use development, such as forestry and agricultural development, were about 2 times higher than that under initial development conditions, leading to accelerated lake shallowing over the last ca 50 years. Sedimentation rates differed with location in the lake because of spatial variation in the sediment flux from the contributing rivers and their catchments. The sedimentation rates before 1963 were low in all sites except for one site close to the Shirarutoroetoro River. The sedimentation rate in 1739~1963 was accumulated mostly at the inflow of the Shirarutoroetoro River by sediment production associated with forestry for charcoal production and initial agricultural development. The sedimentation rate after 1963 increased. In particular, the southern zone of the lake near the conjunction with the Kushiro River had a high sedimentation rate, which is attributable to sediment inflow back from the Kushiro River during floods.

• 한국농공학회지
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• 제38권2호
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• pp.97-107
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• 1996

This study was performed to derive the formula of sediment yield and predict the sediment elevation for fresh desalted reservoirs. Data analyzed was from 3 fresh desalted reservoirs of Sapkyo, Asan, and Namyang. Average sediment yield calculated from the sediment survey data was $279m^3/km^2/$ year for Sapkyo lake, $523m^3/km^2/$ year for Namyang lake, and $190m^3/km^2/$ year for Asan lake. The trap efficiency for Sapkyo lake was 63%. The formula of sediment yield was derived as $Q_s=6,461{\times}A{^-0.44}$ for fresh desalted reservoir. Sediment yield in fresh desalted reservoirs was much higher than that in inland reservoirs located in the same watershed, because of long trap time in fresh desalted reservoirs.

• 한국환경과학회지
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• 제8권5호
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• pp.593-600
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• 1999

In order to determine the changes of sediment facies and metal levels in surface sediments after the construction of Shiwha Lake, surface sediments were sampled at 8 sites located on the main channel monthly from June, 1995 to August, 1996 and analysed for 12 metals (Al, Fe, Mn, V, Cr, Co, Ni, Cu, Zn, Cd, As and Pb) by ICP/AES and ICP/MS. Two groups of sampling sites(the inner lake with 3 sites and the outer lake with 5 sites) are subdivided by the surface morphology ; the inner lake is a shallow channel area with a gentle slope, while the outer lake is relatively deep and wide channel with a steep slope which has many small distributaries. After the construction of dam, fine terrestrial materials were deposited near the outer lake, which resulted in the change of major sediment facies from sandy silt to mud. With the deposition of fine sediments in the outer lake, anoxic water column induced the formation of sulfide compounds with Cu, Cd, Zn and part of Pb. Metal (Cr, Ni, Cu, Zn and Cd) contents in sediments increased up to twice within 2 years after the construction of dam. This is due to the direct input of industrial and municipal wastes into the lake and the accumulation of metals within the lake. In addition, frequent resuspension of contaminated sediments in a shallow part of the lake may make metal-enriched materials transport near the outer lake with fine terrestrial materials. As the enrichment of Cu, Zn, Cd and part of Pb in the Shiwha Lake may be related to the formation of unstable sulfide compounds by sulfate reduction in anoxic water or sediment column, the effect of mixing with open coastal seawater is discussed.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2005년도 학술발표회 논문집
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• pp.1-8
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• 2005

Baiyangdian Lake, the largest freshwater lake in North China, is known as 'Pearl of North China' and 'kidney of North China' fur its abundant products and multiple ecological services. However, from the 1970s, due to the ever-increasing discharge of polluted water from upstream rivers, it has been severely polluted. Sediment Investigation and analysis were conducted on contents of heavy metal (Cu, Zn, Cd and Pb) from Baiyangdian Lake in June 2004. Results showed that pollution situation at downriver regions are more serious than that of upstream regions. The seriously polluted spots are access of Fuhe River, original wastewater reservoir of Tanghe River, densely populated Chunshui Village and Wangjiazhai Village. By using method of the potential ecological risk assessment, the heavy metal evaluation of polluted sediment has been conducted. The results showed that the contents of Cd and Pb were very high in sediment of Baiyangdian Lake. There were extremely stronger ecological risk for Cd and slight- medium ecological risk for Pd. According to the current situation of Baiyangdian Lake, countermeasures and suggestions have been put forward.

• 한국제4기학회지
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• 제19권1호
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• pp.41-46
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• 2005

This study discusses the soil erosion on hillslopes and sediment deposition in lakes within catchments in South Korea. In order to determine seasonal variations of sedimentation in Yeongcheon and Seondong lakes, the sediment traps were set in the deep part of both lakes and lake sediments have been sampledmonthly from July 2004 to August 2005. Some properties such as highmineral content, fine particle size and high particle density in the Yeongcheon Lake indicate intensive soil erosion, sediment transportation and deposition throughout the catchment for a long time. The high sediment yield in the Seondong Lake is related with higher weathering intensity and extreme soil erosion by running water due to higher seasonal rainfall amount. Rates of erosion and sedimentation in the Seondong Lake are estimated to be higher than those of the Yeongcheon Lake, suggesting that the Seondong Lake is associated with higher precipitation, smaller catchment area, and extreme soil vulnerability to ephemeral erosion by overland flow during the heavy rainfall event. Consequently, both catchments are characterized by different erosion and sedimentation processes, as well as different geomorphic factors (bedrock, soil structure, rainfall intensity and catchment area).

• 한국환경보건학회지
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• 제38권5호
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• pp.424-430
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• 2012

Objective: The purpose of this study was to present the standard deviation of the elemental normalization of concentration of selected heavy metals in the surface sediment of Lake Paldang. Methods: Grain size dependency of selected heavy metal concentrations in the surface sediments of Lake Paldang was analyzed by the extrapolation method. The heavy metal concentrations were the sum of all fractions. Results: Cd and Cu showed an increase of the coefficient of determination($r^2$) in the fractional content of particle size, from <256 ${\mu}m$ to <20 ${\mu}m$, and a decrease from <20 ${\mu}m$ to <1 ${\mu}m$. The normalized concentration of Cd and Cu by extrapolation at 50% <20 ${\mu}m$ were 0.8 mg/kg, 37.0 mg/kg, 57.6 mg/kg and 201.7 mg/kg respectively. Conclusions: The normalized concentrations in the sediment of Lake Paldang are 1.5-2.0 times higher than mean average concentration. We concluded that in interpretation of heavy metal concentration in the sediment of Lake Paldang, normalization of grain size dependency should be considered.

• 환경영향평가
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• 제7권2호
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• pp.5-14
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• 1998

This study was performed to estimate interrelation between characteristics of sediment and nutrient releare from sediment in Dae-cheong lake. For the investigations, sediments were sampled in June and October 1997 at fish farms, embayment, and the main stream of Dae-cheong lake. Items for investigation are as follows; water content, weight loss on ignition(IG), porosity of sediment, Total Kjeldahl Nitrogen(TKN), content of element(H, N, C), nutrient release rate. Water content and porosity were measured to conjecture the physical trait and grain size. And weight loss on ignition was measured to determine the contents of organic substance. For the determination of nutrient release rate, $PO_4-P$ and $NH_4-N$ concentration of interstitial water and overlying water were measured. Release rate of nutrients which has direct influenced upon the water quality were 0.05-8.63mg-$P/m^2{\cdot}day$ and 4.99-36.56mg-$N/m^2{\cdot}day$. And it was found that release rate was measured higher in the 1st sampling than in the 2nd sampling. And for determination of the humus level of sediment, carbon and nitrogen content were measured by using elemental analyzer. Generally, C/N ratio is used to determine humus level of lake sediment. As a result of elemental analysis, C/N ratio was determined in the range of 7.64~11.55, so humus level of Dae-cheong lake sediment was estimated from mesohumic state to oligohumic state.

• 한국토양비료학회지
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• 제27권2호
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• pp.111-116
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• 1994

댐 저위층에 축전된 저니와 수강조류를 규조토드럼에 흡착시킨 물질에 대한 농업적 활용 가능성을 검토하기 위하여 Windrow method를 이용한 저니의 부숙퇴비화를 시도하였으며, 저니자체 및 저니함유 부숙퇴비에 대하여 토마토를 공시하여 식물영양적 효과를 포트실험으로 조사한 결과는 다음과 같다. 1. 생계분과 톱밥을 부재료로 한 저니의 부숙방법은 Windrow method를 이용하였다. 부숙과정중 50일 경과후 최종 대(對) 초기 탄질율의 비율은 0.69 수준으로 감소하였고, 양이온치환용량은 약 66%가 증가하였으며, 온도변화는 15일째 $52^{\circ}C$까지 상승하였다가 50일 경과후 $30^{\circ}C$를 유지하여 이 지점을 부숙완료점으로 판정하였다. 2. 미부숙 저니의 토마토에 대한 건물중, 초장 및 엽록소함량에 미치는 효과를 검토한 결과, 대조구에 비해 미부숙 저니 시용구의 효과가 현저하였으며, 시용 수준의 증가와 더불어 건물중 및 초장이 증가하는 경향이었다. 저니 부숙퇴비의 시용 역시, 대조구에 비하여 생체중, 건물중 및 초장의 현저한 증가효과를 나타내었으며, 미부숙 저니에 비해 저니부숙퇴비의 생육효과가 우수하였다. 3. 미부숙 저니 및 저니부숙퇴비를 시용하여 작물재배 후 토양의 물리화학성질을 조사한 결과, pH, T-N, O.M. 및 CEC 면에서 다소 개선효과가 나타났다. 그러므로 저니 및 조류를 직접 토양에 이용하기는 곤란하나 퇴비제조시 충진제로 사용했을 때 부숙화된 저니 퇴비는 토양개량제 및 퇴비자원으로 활용할 수 있는 가능성이 있다고 판단된다.