• 한국생태학회:학술대회논문집
• /
• 한국생태학회 1999년도 국제 Symposium 및 '99 춘계 공동 학술 발표대회
• /
• pp.71.1-71.1
• /
• 1999

• 한국지구물리탐사학회:학술대회논문집
• /
• 한국지구물리탐사학회 2003년도 Proceedings of the international symposium on the fusion technology
• /
• pp.370-378
• /
• 2003

Continuous seismic refraction, reflection and echo-sounder surveys conducted at Koyna Project site provided geotechnical information which helped in choosing the alignment for Head race tunnel and in designing and choosing the site for Lake Tap. Seismic refraction survey both on land and in shallow water determined depths to bedrock and helped in inferring the bedrock quality. Seismic reflection survey mapped the subsurface stratigraphy with high resolution. Reservoir-bed and bedrock contours drawn from the results of the survey helped in choosing the tunnel alignment and the lake tap position cost effectively. It was inferred from the results of the survey that the geology and the quality of rock do not change unexpectedly around the site for extension of Head race tunnel and the lake tapping. The bedrock levels evaluated by seismic survey agreed remarkably well with those inferred in boreholes having Rock Quality Designation 90 percent or more.

• 한국물환경학회지
• /
• 제25권5호
• /
• pp.742-749
• /
• 2009

To examine the characteristics of the nutrient release from the sediments in two reservoirs, Lake Paldang and Lake Cheungpyeung, we analyzed physical and chemical properties of the sediments and calculated the nutrient release rates from the sediments. The particle properties of sediments in Lake Paldang changed from silt to sand after summer rainy season, especially in the water area of the Kyeungan River where the water depth was shallow and the width of river was narrow. The sediments in Lake Cheungpyeung had higher contents of silt and clay than in Lake Paldang, and the particle size was not much different before and after rainfall. The release rates of nutrients in two lakes varied with the kind of nutrients and the season. The release rates of DTN and ${NH_4}^+-N$ in Lake Paldang were faster in spring than autumn. But the Lake Cheungpyeung showed similar values of release rates before and after summer rainy season. ${NO_3}^--N$ and phosphorous were not released from sediments or were absorbed into sediments all the time in two lakes. Compared with other lakes, the sediments of two lakes consisted of bigger particles and had a lower organic matters content than other lake-type reservoirs. Due to the short hydraulic retention time and no stratification throughout the year in Lake Paldang and Lake Cheungpyeung, the release rates of nutrients from sediment in these reservoirs were lower than other lakes and this seems to be a typical characteristic of river-type reservoirs.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2012년도 학술발표회
• /
• pp.1-10
• /
• 2012

Throughout much of the world, many ecological problems have arisen in watersheds where a significant portion of stream flows are diverted to support agriculture production. Within endorheic watersheds (watersheds whose terminus is a terminal lake) these problems are magnified due to the cumulative effect that reduced stream flows have on the condition of the lake at the stream's terminus. Within an endorheic watershed, any diversion of stream flows will cause an imbalance in the terminal lake's water balance, causing the lake to transition to a new equilibrium level that has a smaller volume and surface area. However, the total mass of Total Dissolved Solids within the lake will continue to grow; resulting in a significant increase in the lake's TDS concentration over time. The ecological consequences of increased TDS concentrations can be as limited as the intermittent disruption of productive fisheries, or as drastic as a complete collapse of a lake's ecosystem. A watershed where increasing TDS concentrations have reached critical levels is the Walker Lake watershed, located on the eastern slope of the central Sierra Nevada range in Nevada, USA. The watershed has an area of 10,400 sq. km, with average annual headwater flows and stream flow diversions of 376 million $m^3/yr$ and 370 million $m^3/yr$, respectively. These diversions have resulted in the volume of Walker Lake decreasing from 11.1 billion m3 in 1882 to less than 2.0 billion $m^3$ at the present time. The resulting rise in TDS concentration has been from 2,560 mg/l in 1882 to nearly 15,000 mg/l at the current time. Changes in water management practices over the last century, as well as climate change, have contributed to this problem in varying degrees. These changes include the construction of reservoirs in the 1920s, the pumpage of shallow groundwater for irrigation in the 1960s and the implementation of high efficiency agricultural practices in the 1980s. This paper will examine the impacts that each of these actions, along with changes in the region's climate, has had on stream flow in the Walker River, and ultimately the TDS concentration in Walker Lake.

• 한국환경생태학회지
• /
• 제29권2호
• /
• pp.210-220
• /
• 2015

We quantified temporal and spatial changes in the habitat for fish populations, the distribution of mandarin fish(Siniperca scherzeri) and an introduced species, largemouth bass(Micropterus salmoides) in Lake Paro and inflowing streams. The number of fish species identified in Lake Paro and the tributary streams included 10 families, 24 species and 10 families 30 species, respectively. The dominant fish species in Lake Paro were Zacco platypus, Hemibarbus labeo, Squalidus gracilis majimae, S. scherzeri and Tridentiger brevispinis, Z. platypus, Z. koreanus, and S. gracilis majimae in the inflowing streams. Although the habitat segregation for S. scherzeri and M. salmoides occurs, these two species showed the use of the fishes of the family Gobiidae as an important prey item based on IRI analysis. S. scherzeri and M. salmoides preyed mainly on T. brevispinis(67.4 %) and R. brunneus(84.0 %), respectively. The species preyed on by S. scherzeri and M. salmoides were benthic fishes that inhabit shallow water depths around the lake and have little swimming ability.

• 한국미생물·생명공학회지
• /
• 제27권4호
• /
• pp.273-277
• /
• 1999

From each sediments collected at Chudong(static) and Hoenam(streaming) site of Lake Daechung on May 18(before rainy season) and on August 24 in 1998(after rainy season), different strains of Actinomycetes were isolated and identified to genus level. For comparison, the genus diversity of Actinomycetes in control soils such as grass land around lake, lake shore, and shallow(5-10cm) lake was also investigated. In consequence, the isolation of Streptomyces from the sediments of Lake Daechung was the most copious(41 strains) at the streaming site before rainy season and the least(27 strains) at the static site before rainy season, which were 2.4- and 1.6-fold larger than the average(17 strains) of control soils, respectively. In addition, the isolation of rare Actinomycetes from the sediments of Lake Daechung was the most copious(23 strains) at the streaming site before rainy season and the least(12 strains) at the static site after rainy season, which were 3.2-and 1.6-fold larger than the average(17 strain) of controls, respectively. Therefore, it is considered that lake sediments exhibit higher diversity of Streptomycete as well as rare Actinomycetes than general soils, and thereby can be utilized as useful sources to isolate diverse Actinomycetes.

• 한국수자원학회:학술대회논문집
• /
• 한국수자원학회 2005년도 학술발표회(1)
• /
• pp.467-468
• /
• 2005

• 한국동물학회:학술대회논문집
• /
• 한국동물학회 2000년도 한국생물과학협회 학술발표대회
• /
• pp.145.1-145
• /
• 2000

No Abstract, See Full Text

• 생태와환경
• /
• 제33권3호통권91호
• /
• pp.197-205
• /
• 2000

동물플랑크톤의 성장률과 밀접한 상관 관계를 가지는 요인들에 대해 스프리 강 중류의 호수 및 강 구획 (호수 유입부 (S1), 호수 유출부 (S2), 호수 유출부 지점에서 21 km 하류지점 (S3))에서 1999년 3월부터 11월까지 조사하였다. 총 동물플랑크톤 생체량은 S2지점에서 크게 증가하였고 S3에서 급격하게 감소하였다. 모든 조사지점에서 소형동물플랑크톤(윤충류와 유생)의 개체수는 대형동물플랑크톤(지각류와 요각류)의 개체수 보다 매우 높았다. 그러나, 대형동물플랑크톤의 생체량은 소형동물플랑크톤 생체량과 유사하거나 높았다. 대형 지각류 (Daphnia cucullata)는 조사지점 S2에서 우점한 반면, 조사지점 S1과 S3에서는 소형 지각류 (Bosmina longirostris)가 우점하였다. 주요 동물플랑크톤 군집의 성장률 ($r_t\;in\;d^{-1}$)은 조사지점 S1 과 S2사이 (호수구획)와 S2와 S3사이 (강 구획)에서 매우 달랐다. 호수 구획 내에서의 성장률은 양성적인 유형을 나타낸 반면 강 구획 내의 성장률은 음성적인 양상을 나타내었다. 여러 환경 요인 중, 스프리강 중류지점에서는 수체의 잔류시간(partial retention time: PRT, $d^{-1}$) 이 동물플랑크톤 군집구조의 특성을 결정짓는 가장 중요한 요인으로 사료된다.

• 생태와환경
• /
• 제38권2호통권112호
• /
• pp.249-260
• /
• 2005

전남-광주권의 주요 상수원의 하나인 주암호의 2개 정점 (취수탑, 문덕교)에서 2003년 1월부터 12월까지 매월1회씩 환경요인과 식물플랑크톤 군집의 변동을 조사하였다. 조사기간 동안 두 정점의 환경요인은 큰 차이를 보이지 않았으나 식물플랑크톤 출현 및 종 조성은 뚜렷한 차이를 나타냈다. 식물플랑크톤은 6분류군 중 녹조류 (41.8%), 규조류(35.8%)가 가장 높은 종 출현을 보였으며, 와편모조류 (46.3%), 남조류 (27.6%)가 가장 높은 현존량을 나타냈다. 취수탑에서는 저온기를 중심으로 주로 Peridinium bipes, 문덕교에서는 고온기를 중심으로 Microcystis aeruginosa가 각각 우점하였으며, 수온 및 조사 정점에 대한 지표성이 높았다. CCA 분석에 따르면, P, bjpes은 DO와 COD에 의해, M. aeruginosa는 수온이나 총질소에 크게 영향을 받는 것으로 나타났다. 따라서 주암호의 식물플랑크톤 군집은 1차적으로 수온에 의해 크게 지배되며, 호수내 연간 1차 생산에 있어 두 우점종 P, bjpes, M. aeruginosa가 가장 크게 기여하는 것으로 나타났다.