Wyniki wyszukiwania - Biblioteka Nauki

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Assessment of characteristics, water quality and groundwater vulnerability in Pakis District, East Java Province, Indonesia

100%

Rubiantoro P. , Bisri M. , Afandhi A.

Journal of Water and Land Development

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2022

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tom no. 52

124--132

EN

Groundwater is a very important natural resource to support the activities of the residents of Pakis District, Malang Regency. On the other hand, increased activity puts pressure on groundwater quality. Agricultural intensification, urbanisation, and industrialisation can be sources of pollutants. Hydrological factors, topography, lithology, and surrounding rainfall are triggers for contamination of groundwater. The main objective of this research is to determine the characteristics, quality of groundwater, and its susceptibility to pollution. To complete this research, geoelectric measurements were carried out at 43 points spread throughout the study area and sampling of 18 shallow wells in agricultural, residential, and industrial areas for chemical analysis. All data obtained were analysed to create a map of the spatial distribution of groundwater vulnerability. The results show that the groundwater in the study location is in the transition zone and flows through the volcanic rock layers. The level of groundwater pollution is in the uncontaminated status to heavily polluted with pollutants in the form of heavy metal manganese and Escherichia coli bacteria. The spatial distribution of groundwater intrinsic vulnerability shows low, moderate, and high levels of vulnerability, respectively 32.99%, 60.87%, and 6.14% of the research area. Groundwater specific vulnerability associated with land use factors shows that 26.25% are negligible, 42.46% are low, and 31.29% are moderate. From this it can be concluded that the study area has been polluted both geogenically and anthropogenically, therefore, special actions must be taken to restore the quality of groundwater.

2

Inundation controlling practice in urban area: Case study in residential area of Malang, Indonesia

100%

Harisuseno D. , Bisri M. , Haji T. S.

Journal of Water and Land Development

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2020

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tom no. 46

112--120

EN

Flood inundation processes in urban areas are primarily affected by artificial factors such as drainage facilities, local alterations of topography and land uses. The objective of this study is to examine the capability of hydrological model SI-MODAS to estimate runoff and investigating the utilization of storage well in controlling runoff in a residential area. The result of the estimated runoff from the hydrological model was compared with the existing capacity of the drainage channel to identify which channel experienced the problem of inundation. The location of inundation was used to determine the location and number of storage well. The results showed that SIMODAS model could be applied in runoff analyses with 8.09% of relative error compared with runoff depth from field measurement. The existing capacity of the channel could not accommodate runoff Q10yr where the inundation discharge was approximately 0.24 m3·s–1 (at outlet point 1) and 0.12 m3·s–1 (at outlet point 2). The inundation problem was overcome by using a combination system between channel normalization (reduce 35% of total inundation discharge) and storage well system (reduce 65% of total inundation discharge). The storage well was designed at 20 locations (at outlet point 1) and 16 locations (at outlet point 2) which each well had a discharge of 0.0058 m3·s–1. The storage well combined with channel normalization could be used as an alternative way to solve inundation problems in a residential area considering the constraint of land space limitation in the urban area.

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Soil Textures-Based Evaluation of Horton and Philip’s Infiltration Models for Equatorial Small Watersheds

100%

Pristianto H. , Suhardjono , Bisri M. , Suhartanto E.

Journal of Ecological Engineering

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2024

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tom Vol. 25, nr 2

103--114

EN

The global database underscores Indonesia’s scant 0.47% global contribution, of which 7.7% is from humid tropical climates. However, existing infiltration studies have primarily focused on specific soil textures and limited research points, resulting in a lack of comprehensive data. This knowledge gap is particularly evident in the Papua region of Indonesia, which boasts many small watersheds with abundant water resources but limited hydrologic data, especially regarding infiltration rates. Previous studies indicated that Horton and Philip’s models excelled in equatorial regions but were limited in the number of soil textures and watersheds analysed or focused mainly on larger watersheds. Therefore, this study aimed to address this research gap by conducting a comprehensive analysis of the performance of the Horton and Philip’s models across different soil textures in small watersheds, using the Hydrologic Soil Group classification as a reference. A performance analysis was conducted to assess Horton and Philip’s performance using the Moriasi technique (based on R, RSR, and NSE best values). Field observations were conducted at 95 points in eleven small watersheds in Papua as representatives of equatorial small watersheds globally. Observations were suspended for 48 hours if rainfall occurred; thus, ten months were needed to finish the observation. The results of this study demonstrated that the Horton model performed exceptionally well for six of nine soil textures, whereas the Philip’s model showed excellent performance for five out of nine. The obtained research results were compared with similar studies from Ghana, Nigeria, and India, reinforcing the conclusion that globally, the Horton and Philip’s model effectively describes infiltration rates in equatorial small watersheds. Further research was recommended in equatorial small watersheds with sand and loamy sand soil textures, two of the nine soil textures that were not covered in the conducted study.

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El-Nino effect on reservoir capacity reliability: Case study of Sumi dam, Sumbawa Island, Indonesia

88%

Andawayanti U. , Yasa I. W. , Bisri M. , Sholichin M. , Sulianto

Journal of Water and Land Development

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2020

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tom no. 44

1--7

EN

Reservoirs have a very important function in providing multi-sector water requirements. In the future, reservoirs not only serve to store and available water can also be used as disaster mitigation instruments. The completeness of hydrological measurements in reservoirs can be expanded more widely for climate change mitigation. The reliability of the reservoir capacity varies greatly depending on the El-Nino character that occurs among them El-Nino is weak, moderate, strong and very strong. The El-Nino characteristic is very influential on the period of water availability, the increase of evaporation capacity and decrease of reservoir capacity. Analysis of the reliability of the reservoir volume due to El-Nino using the Weibull equation. The deficit reservoir was calculated using the concept of water balance in the reservoir that is the relationship between inflow, outflow, and change of storage at the same time. Based on the results of the analysis showed that the evaporation increase and the decrease of reservoir capacity had a different pattern that is when the evaporation capacity started to increase at the same time the reservoir capacity decreased significantly. The correlation coefficient between evaporation capacity increase and decrease of reservoir water capacity are consecutively –0.828, –0.636, and –0.777 for El- Nino weak, moderate and very strong respectively. At the reservoir capacity reliability of 50% reservoir has a significant deficit. When weak El-Nino the deficit is 2.30∙106 m3, moderate: 6.58∙106 m3, and very strong 8.85∙106 m3.