Article Per Year (5 Year)
p-Index From 2019 - 2024
0.23
P-Index
This Author published in this journals
All Journal Indonesian Journal of Geography Indonesian Journal of Limnology
Takehiko Fukushima
Unknown Affiliation
Chemical Engineering, Chemistry & Bioengineering Earth & Planetary Sciences Environmental Science

Published : 2 Documents Claim Missing Document
Claim Missing Document
Check
Articles

Found 2 Documents
Search

 1 
THE CHANGES IN STREAM WATER TEMPERATURE AND WATER QUALITY PARAMETERS DURING RAINFALL EVENTS IN FORESTED WATERSHEDS: SCALING OF OBSERVATIONS Luki Subehi; Takehiko Fukushima; Yuichi Onda; Shigeru Mizugald
Indonesian Journal of Geography Vol 42, No 2 (2010): Indonesian Journal of Geography
Publisher : Faculty of Geography, Universitas Gadjah Mada

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.22146/ijg.2289

Abstract

We studied the changes in stream water temperature (Tw) and waterquality (Wq) during rainfall events in forested watersheds. The parameters ofWq(88, DOC, N03--N, DTN, Na+, 8i and r) were observedinfour regionsof Japanfrom June 2004 to December 2005. The R values between Tw and those Wqparameters and between specific discharge (Qs) and Wq were positive, exceptforthe negativeones (Na+ and Si). Similarto the relationbetweenQs vs. Tw, hystereticloops in the relations between Qs vs. those Wqparameters were clockwise,exceptfor Na+ and Si as counter-clockwiseloops. This indicatesthat the'surfaceand subsurface flows contain higher concentrations of SS, DOC, IC, N03--N andDTN. To the contrary,the deeperpathwayscontainhigherconcentrationsof Na+and Si. These results suggest that the changes in Tw and Wq could be used tointerpret theflow paths.
Dissolved Oxygen Profiles and Its Problems at Lake Maninjau, West Sumatra – Indonesia Luki Subehi; Iwan Ridwansyah; Takehiko Fukushima
Indonesian Journal of Limnology Vol. 1 No. 1 (2020): Indonesian Journal of Limnology
Publisher : Indonesian Society of Limnology

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (439.808 KB) | DOI: 10.51264/inajl.v1i1.3

Abstract

In general, the tropical lake in Indonesia is one of the unique ecosystems which are functioning in both ecological and economic services. This study aims to analyze the dissolved oxygen profile of caldera tropical lake represented by Lake Maninjau at West Sumatera, Indonesia, and its impacts. Lake Maninjau is not only for culture fisheries but also serves as important hydroelectricity power. Surveys at Lake Maninjau were conducted in August 2006, March 2014, September 2017, and April 2018. The results showed that the average depth is 105 m. It covers 13,260 ha of an area with an elevation of 461.5 m above sea level and a maximum depth of 165 m. The lake water comes from rainfall, small rivers, and the surrounding groundwater, with one outflow in the Batang Antokan River. Based on the measurement, it was observed that decreasing dissolved oxygen levels occurred at the surface to the depth of 40 m in 2006, and changed from surface to a depth of 12 m in 2018 indicating the worse condition of water quality compared with the previous years.  Recently, bad water quality with mass mortality of cultured fish often occurs. Next, the percentage of fish cages area at Lake Maninjau in 2017 was 0.43%. Besides human activities, it was suggested that fish cages also contributed pollutant load to this lake. To maintain the sustainability of the lake, basic ecological information is necessary for the next study.
Co-Authors Iwan Ridwansyah Luki Subehi Luki Subehi Shigeru Mizugald Yuichi Onda