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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.
Surface Sediment Diatom as A Water Quality Indicator: Case Study: Cilalay and Cibuntu Ponds, Cibinong Aan Dianto; Taofik Jasalesmana; Luki Subehi; Ahmad Yusuf Afandi; Ardo Ramdhani
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 (275.996 KB) | DOI: 10.51264/inajl.v1i1.1

Abstract

Diatom is classified as algae within the Division of Bacillariophyta. They are unicellular eukaryotic organisms characterized by siliceous cell walls that can be long preserved in sediments. Therefore, diatom analysis in sediment records is a potential water quality indicator for present or paleo studies. The current knowledge on the distribution and diversity of diatoms in the sediment in the urban pond is poorly known. This study aimed to identify the distribution and diversity of diatoms from the sediments of the pond. We expect to obtain a primary database of a variety of diatoms. The sediment samples were taken from Cibuntu and Cilalay Ponds in Cibinong Botanical Garden. Sediments were digested using HCL and H2O2. The resulting diatom solution was dried and transferred onto glass coverslip, which subsequently mounted onto microscope slides using Naphrax (Refraction index 1.7). Diatom identification was examined using a light microscope at 1,000x magnification. Diatom communities in Cibuntu Pond were dominated by species Aulacoseria ambigua, Eunotia bilunaris, Cymbopleura sp, Discostella stelligera, and Rossithidium sp with diversity index of 2.4 and species evenness of 0.8. Whereas, species Fragilaria sp, Eunotia monodon, Navicymbula pusilla, Eunotia bilunaris, and Pinnularia viridis were predominant in Cilalay Pond with diversity index of 1.6 and species evenness of 0.5. Based on the diatom community, Cibuntu Pond is eutrophic indicated by the occurrence of Aulacoseria ambigua, whereas Cilalay Pond is meso-eutrophic indicated by the dominance of Fragillaria. This exploratory survey provides the first inventory of diatom assemblage in Cibuntu and Cilalay Ponds for roughly inferring the environmental changes in a shallow lake ecosystem.
PENENTUAN BATAS TEPI DANAU PAPARAN BANJIR SECARA HITUNG PERATAAN KUADRAT TERKECIL DENGAN MULTIDATA PENGINDRAAN JAUH Atriyon Julzarika; Esthi Kurnia Dewi; Luki Subehi
LIMNOTEK Perairan Darat Tropis di Indonesia Vol. 26 No. 2 (2019)
Publisher : BRIN Publishing

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.55981/limnotek.2019.13367

Abstract

Nowadays, technology and remote sensing data have developed significantly. These developments started with conventional data to become dynamic data. Technology and remote sensing data can be used for various applications such as mapping of inland water. Inland water resources that include lakes, rivers, and swamps are one of the national priorities, especially in lake mapping. One of the problems with floodplain lakes is that it is difficult to determine the fixed boundaries of the lake surface area. This study aims to obtain a forensic geological boundary mapping of a lake using the least-square adjustment approach in a floodplain lake with multi-data remote sensing. The floodplain lake in this study was Mahakam Cascade Lake in East Kalimantan Province. The fixed boundary of the surface area of the lake was determined using the least-square adjustment approach. One method in the adjustment was the harmonic modeling algorithm. This mapping used multi-data remote sensing in the form of Synthetic Aperture Radar (SAR) and optical imagery. The imagery used was Sentinel-1 which was acquired from 2014 to 2018 and Landsat from 2014 to 2018. This algorithm showed that the fixed boundaries of Mahakam Cascade Lake can be determined with certain tolerances. These fixed boundaries ignored lake tide parameters because the maximum tide value in the lake was only +5 cm. This value was ignored because the vertical accuracy of the topographic data in the big data engine was about 2 m. The fixed delineation of lake edges can be used to determine the lake volume and surface area. The surface area of the lake obtained from the Sentinel-1 imageries was ~ 399,017 km2. Based on Landsat imageries, the surface area of the lake was ~ 399,495 km2. The difference was due to the mixing of sediments and thin turbidity at the edge of the lake. This condition caused differences in reflectance values when acquisitioning the two types of imageries. Basically, this method could be applied for determining the edge of a lake.