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Image blending is one of the alternative methods to fill temporal gaps in the monitoring of historical vegetation properties using continuous NDVI derived from Landsat 5 TM / 7 ETM+ and 8 OLI images. Frequent cloud occurrence in the tropical upstream catchment limits the use of image blending methods that allow to employment of a single pair base reference. This study aims to evaluate two image blending methods with nine input data configurations to select the most applicable one. Scatter plots and statistical indices such as ME, RMSE, model efficiency and structure similarity showed FSDAF outperforms STARFM in generating both synthetic Landsat 8 OLI NDVI and Landsat 5 TM / 7 ETM+ NDVI when employing unsupervised and supervised classification images, respectively, where both were applied along with MODIS NDVI 250 m v.005. When generating synthetic Landsat 5 TM / 7 ETM+ NDVI using AVHRR NDVI, both algorithms performed similarly. However, when considering the temporal over spatial variance ratio between base reference and predictor images, both algorithms performed almost similar when the value close to minimum. This study shows that selection of image blending algorithm with use single pair base reference image should consider input data configuration and temporal over spatial variance ratio. [ABSTRACT FROM AUTHOR]

Background: This study aims to assess the effects of a forestation program and climate change on the annual and seasonal water balance of the Bogowonto catchment (597 km2) in Java, Indonesia. The catchment study is rare example in Indonesia where forestation has been applied at the catchment level. However, since the forestation program has been initiated, evaluations of the program only focus on the planting area targets, while the environmental success e.g., impacts on the hydrological processes have never been assessed. This study used a calibrated Soil and Water Assessment Tool (SWAT) model to diagnose the isolated and combined effects of forestation and climate change on five water balance components, namely streamflow (Q), evapotranspiration (ET), surface runoff (Qs), lateral flow (Ql) and base flow (Qb). Results: The results show that from 2006 to 2019, forest cover has increased from 2.7% to 12.8% of the total area, while in the same period there was an increase in the mean annual and seasonal temperature, rainfall, and streamflow. Results of SWAT simulations show that changes in the mean annual and seasonal water balance under the forestation only scenario were relatively minor, while changes were more pronounced under the climate change only scenario. Based on the combined impacts scenario, it was observed that the effects of a larger forest area on the water balance were smaller than the effects of climate change. Conclusions: Although we found that forestation program has minor impacts compared to that of climate change on the hydrological processes in the Bogowonto catchment, seasonally, forestation activity has decreased the streamflow and surface runoff during the wet season which may reduce the risk of moderate floods. However, much attention should be paid to the way how forestation may result in severe drought events during the dry season. Finally, we urge the importance of accounting for the positive and negative effects in future forestation programs. [ABSTRACT FROM AUTHOR]

This study investigated the influence of land use change and climate change on changes in streamflow in the Bengawan Solo River (BSR, 16 389 km2) basin, Indonesia. We applied the excess water and energy approach to three tributaries of the BSR, namely Pidekso, Madiun and Kening rivers, which represent the up-, mid-, and downstream parts of the BSR, respectively. This study used hydrological data from 1982−2013 and land use data for the years 1994 and 2013. The results show that from 1982 to 2013, the annual streamflow of the Pidekso and Madiun River increased, while in the Kening River it decreased. Based on attribution measures, the increasing streamflow trend in the Pidekso and Madiun rivers is mainly attributed to land use change, while the decreasing streamflow trend in the Kening River is mainly attributed to climate change. These conclusions are supported by statistical analyses and land use change analysis. [ABSTRACT FROM AUTHOR]

Hydrological models often require input data on soil-water retention (SWR), but obtaining such data is laborious and costly so that SWR in many places remains unknown. To fill the gap, a prediction of SWR using a pedotransfer function (PTF) is one of the alternatives. This study aims to select the most suitable existing PTFs in order to predict SWR for the case of the upper Bengawan Solo (UBS) catchment on Java, Indonesia. Ten point PTFs and two continuous PTFs, which were developed from tropical soils elsewhere, have been applied directly and recalibrated based on a small soil sample set in UBS. Scatter plots and statistical indices of mean error (ME), root mean square error (RMSE), model efficiency (EF) and Pearson's correlation (r) showed that recalibration using the Shuffled Complex Evolution-University of Arizona (SCE-UA) algorithm can help to improve the prediction of PTFs significantly compared to direct application of PTFs. This study is the first showing that improving SWR-PTFs by recalibration for a new catchment based on around 50 soil samples provides an effective parsimonious alternative to developing a SWR-PTF from specifically collected soil datasets, which typically needs around 100 soil samples or more. [ABSTRACT FROM AUTHOR]

Changes in the stream flow of the Samin catchment (277.9 km²) in Java, Indonesia, have been attributed to land use change and climate change. Hydroclimatic data covering the period 1990-2013 and land use data acquired from Landsat satellite imageries for the years 1994 and 2013 were analysed. A quantitative measure is developed to attribute stream flow changes to land use and climate changes based on the changes in the proportion of excess water relative to changes in the proportion of excess energy. The results show that 72% of the increase in stream flow might be attributed to land use change. The results are validated by a land use change analysis and two statistical trend analyses namely the Mann-Kendall trend analysis and Sen's slope estimator for mean annual discharge, rainfall and potential evapotranspiration. The results of the statistical trend analysis are in the same direction as the results of the attribution analysis, where climate change was relatively minor compared to significant land uses change due to deforestation during the period 1994-2013. We conclude that changes in stream flow can be mainly attributed to land use change rather than climate change for the study catchment. [ABSTRACT FROM AUTHOR]

Abstract: The geographical distributions of polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), hexachlorobenzene, and 1,1-dichloro-2,2-bis(4-chlorophenyl)ethene (4,4′-DDE) were studied in the Berau delta (East Kalimantan, Indonesia), using sediment sampling and passive water sampling with semipermeable membrane devices. High concentrations of perylene were observed in sediments (54–580ngg−1 dry weight), and water (1–680pgL−1). Perylene accounted for about 60% of the total concentrations of PAHs in the sediment. The relative abundance of the other PAHs was indicative of petrogenic sources. Concentrations of PCBs, hexachlorobenzene, and 4,4′-DDE in sediments were below or close to the detection limit (∼0.02ngg−1). The analysis of a sediment core revealed no appreciable changes in the concentration of target compounds over the past three decades. We show that sediment sampling and passive water sampling are complementary techniques, and propose to bring the results of both methods to the same concentration scale, using locally derived sediment–water partition coefficients. [Copyright &y& Elsevier]

National water use accounts are generally limited to statistics on water withdrawals in the different sectors of economy. They are restricted to "blue water accounts" related to production, thus excluding (a) "green" and "grey water accounts", (b) accounts of internal and international virtual water flows and (c) water accounts related to consumption. This paper shows how national water-use accounts can be extended through an example for Indonesia. The study quantifies interprovincial virtual water flows related to trade in crop products and assesses the green, blue and grey water footprint related to the consumption of crop products per Indonesian province. The study shows that the average water footprint in Indonesia insofar related to consumption of crop products is 1131m3/cap/yr, but provincial water footprints vary between 859 and 1895m3/cap/yr. Java, the most waterscarce island, has a net virtual water import and the most significant external water footprint. This large external water footprint is relieving the water scarcity on this island. Trade will remain necessary to supply food to the most densely populated areas where water scarcity is highest (Java). [ABSTRACT FROM AUTHOR]