Asian Journal of Water, Environment and Pollution - Volume 10, issue 1

Article Type: Other

Citation: Asian Journal of Water, Environment and Pollution, vol. 10, no. 1, pp. i-iv, 2013

Authors: Jennerjahn, Tim C. | Adi, Seno | Schroeder, Friedhelm

Article Type: Other

Citation: Asian Journal of Water, Environment and Pollution, vol. 10, no. 1, pp. 1-4, 2013

Authors: Adi, Seno | Jänen, Ingo | Jennerjahn, Tim C.

Article Type: Research Article

Abstract: The Brantas River is the second largest river on the island of Java which has undergone major changes in the past decades because of the demands of an evergrowing population. Water management measures were mainly designed (i) to provide flood protection, (ii) to provide raw water for irrigation, households and industry, and (iii) to generate hydropower. The objective of this paper is to delineate the history of development and attendant environmental changes since 1970 as well …as to address the effects of a mud volcano eruption in 2006. Data from three gauging stations representing the upstream, midstream and downstream portions of the Brantas River were chosen to display patterns in discharge (1970-2003) and in nutrients (1991-1997). Overall discharge decreased over time at all stations with the strongest decrease in the downstream portion. The amplitude of seasonal changes in discharge was highest in the downstream portion. Dissolved inorganic nutrient concentrations increased slightly downstream as a result of land use. An eruption of a mud volcano in 2006 added to the initially high sediment load of the river. A portion of the mud was directed into the river leading to extremely high suspended matter and low dissolved oxygen concentrations. As a large part of the high suspended sediment load, already settled in the river, dredging was initiated in order to avoid blocking of the river. The dredging material was used for land reclamation. The high nutrient and sediment loads of the Brantas River are to a large extent the result of intensive human activities in the catchment like hydrological alterations and land-use change. Extreme natural events like the mud volcano exacerbate the consequences of human alterations on the water quality and biogeochemistry of the river. Show more

Keywords: River, discharge, nutrient, mud volcano, land use change, Indonesia

Citation: Asian Journal of Water, Environment and Pollution, vol. 10, no. 1, pp. 5-15, 2013

Authors: Nugroho, Sutopo Purwo | Adi, Seno

Article Type: Research Article

Abstract: The probable maximum precipitation (PMP) is defined as the highest precipitation (measured by a rain gauge) for a given period that is meteorologically reliably recorded in the rainfall station. Estimation of the PMP is very important, especially for the safety design of dams and reservoirs, because precipitation data are available for a much longer period of time than those for river floods. Analysis of the daily rainfall, which was used to estimate the PMP values of …the upstream Brantas River showed high consistency, so that the collected rainfall data were reliable. These facts were shown by a straight line produced by each rainfall station based on the double mass curve test. The PMP estimation for upstream Brantas River varied between 419 and 556 mm/day. The estimated PMP values were highest at the Birowo station and lowest at the Tangkil station. They were then not correlated to the maximum daily rainfall observed at a rainfall station. This means that there are other factors as described by the Hershfield equation that resulted in higher estimated PMP values. Therefore, the safety design of dam and reservoir construction in this area has to consider the estimated maximum PMP reaching 556 mm/day. Show more

Keywords: Hershfield equation, maximum rainfall, probable maximum flood, probable maximum precipitation, upper river, safety, dam design

Citation: Asian Journal of Water, Environment and Pollution, vol. 10, no. 1, pp. 17-24, 2013

Authors: Schroeder, Friedhelm | Boer, Michael | Wijanarko, Didik Agus

Article Type: Research Article

Abstract: The design, development and operation of an automated water quality station at the banks of the Brantas River, Java, Indonesia is described. The objective of the work was to prove that such a station can be operated in tropical areas with trained local personnel. By designing and building a modular system within a transportable container, a generalised system that can be applied to other tropical or subtropical regions was developed. The main problem in tropical waters …— biofouling of sensors – was solved by automated cleaning procedures that include pressure cleaning with acidified water and chlorination. Low maintenance requirements could be achieved by a completely automated operation and remote maintenance via phone and internet. The different components of the system – water inlet, hydraulic circuit, data management – are described in detail. The performance and the costs of the automated water quality station are discussed. Show more

Keywords: Indonesia, Brantas, river, estuary, water quality, oxygen, automated monitoring, biofouling

Citation: Asian Journal of Water, Environment and Pollution, vol. 10, no. 1, pp. 25-39, 2013

Authors: Jennerjahn, Tim C. | Klöpper, Sascha

Article Type: Research Article

Abstract: The Brantas River catchment on the Indonesian island of Java is among the most densely-populated regions in the world. Damming of the river and intensive agriculture in the catchment are supposed to affect the biogeochemistry and ecology of the river, its reservoirs and coastal waters. We collected water, suspended matter and phytoplankton samples from the Sutami and the Selorejo lakes, two major reservoirs in the catchment, in May 2001 and June 2002. Water samples were analyzed …for dissolved inorganic nutrients and suspended matter was analyzed for carbon and nitrogen contents and stable carbon and nitrogen isotope composition. Phytoplankton cells were counted, identified and grouped into four major classes. Both reservoirs displayed clear signs of eutrophication as shown by high nutrient concentrations and high phytoplankton abundance. Phytoplankton abundance was generally higher in the Sutami than in the Selorejo reservoir and in the Sutami reservoir it was much higher in June 2002 than in May 2001. Phytoplankton responded to the amount and composition of nutrients in such a way that diatoms dominated when silicate concentrations and N/P ratios were high in the Sutami reservoir in May 2001. The mass occurrence of the water hyacinth Eichhornia crassipes in the Selorejo reservoir was probably responsible for a high uptake of dissolved nutrients resulting in an N/P ratio <8. This favoured the growth of cyanobacteria which can fix atmospheric nitrogen. Excessive phytoplankton growth in the Sutami reservoir in June 2002 led to a drastic silicate reduction (165 μM in May 2001, 95 μM in June 2002). This and an N/P ratio <4 consequently resulted in a much lower abundance of diatoms and a much higher abundance of cyanobacteria than in May 2001. The biogenic extraction of silicate by diatoms in reservoirs has often been observed in high latitude regions where it, in combination with high anthropogenic additions of nitrogen and phosphorus and a lack of silicate replenishment downstream of reservoirs, leads to eutrophication of coastal waters and a shift from biomineralizing to nonbiomineralizing phytoplankton. Because of the high weathering rates in the tropical Brantas River catchment, silicate concentrations in the downstream portion of the river were as high as in the headwaters and coastal phytoplankton was dominated by diatoms despite nutrient extraction in reservoirs. It indicates that human activities in river catchments in the humid tropics affect coastal ecosystems in a different way than in high latitude regions. Show more

Keywords: Eutrophication, artificial lakes, suspended organic matter, nutrients, phytoplankton, dam

Citation: Asian Journal of Water, Environment and Pollution, vol. 10, no. 1, pp. 41-53, 2013

Authors: Schroeder, Friedhelm | Knauth, Hans-Diethard

Article Type: Research Article

Abstract: Using an automated water quality station in the lower Brantas River, East Java, Indonesia, highly time-resolved time series (1 min^1 ) of main parameters that govern water quality have been measured (oxygen, chlorophyll-a, turbidity, nutrients, total inorganic and organic carbon) from 2003 to 2008. All parameters showed distinct seasonal variations related to dry and wet seasons. Due to the large input of organic material from sewage and industry into the river the most important parameter …is the dissolved oxygen that displays a distinct seasonal behaviour with relatively large values during wet season and very low values in dry season. In addition, during dry season high variations between day and night were observed with zero oxygen concentrations at night. From highly time-resolved oxygen time series the main metabolic rates (primary production, respiration) together with atmospheric exchange rates could be calculated in a semi-quantitative way. From this, it could be estimated that the anthropogenic carbon input into the river has to be reduced from about 70 t/d BOD equivalents to at least 33 t/d in order to prevent anaerobic conditions. Show more

Keywords: Water quality, automated monitoring, time series, oxygen, BOD, respiration, atmospheric exchange, Indonesia, Brantas

Citation: Asian Journal of Water, Environment and Pollution, vol. 10, no. 1, pp. 55-72, 2013

Authors: Jänen, Ingo | Adi, Seno | Jennerjahn, Tim C.

Article Type: Research Article

Abstract: The Brantas River is a tropical mid-sized river with mountainous headwaters, covering a catchment area of around 11,050 km^2 at the east coast of Java, Indonesia. Its watershed is located in one of the most densely populated regions worldwide, facing alterations by agriculture, urbanization and aquaculture ponds. Additionally, one of the two major distributaries of the Brantas River in the lowlands, the Porong River is affected by inputs from the "LUSI" mud volcano since …April 2006. We investigated spatio-temporal variations in inorganic nutrient biogeochemistry of the Brantas River, its major distributaries in the lower reaches and its coastal-estuarine regions and related them to land use and hydrology. Highest nutrient loadings occurred during the wet periods (November to April) making up 80% and 87% of the annual dissolved inorganic nitrogen (DIN: NO_3^- , NO_2^- , NH_4^ + ) and phosphorus (PO_4^{3-} ) loads, respectively, with the Porong River accounting for 90% and 82% of the annual DIN and PO_4^{3-} input. During wet periods the estuaries were flushed with DIN and PO_4^{3-} rich freshwater, leading to high concentrations in coastal waters. Much lower nutrient concentrations were observed in coastal waters during dry periods because of low river discharge and nutrient load. During dry periods an increased exchange time and increased biological activity were responsible for estuaries acting as a sink for NO_3^- and a source for NH_4^ + and PO_4^{3-} . In contrast, during wet periods most of the introduced NO_3^- was directly discharged into coastal waters without further processing and NH_4^ + and PO_4^{3-} fluxes were slightly lower. Variations in the DIN composition were mainly related to differences in land use with NO_3^- dominating the agriculture-dominated upper Brantas River and increasing NH_4^ + and NO_2^- content in the lower reaches affected by urban wastewater and aquaculture. The mud volcano affected parts of the Porong River showed drastic changes in the DIN composition and depletion of dissolved oxygen during low flow periods. In contrast, during wet periods most of the mud volcano input was diluted by the large freshwater and inorganic nutrient supply from the upstream regions. Our results suggest that the densely urbanized Brantas River with multiple anthropogenic nutrient sources (agriculture, urban sewage release, aquacultures) leads to an increased export of dissolved inorganic nitrogen and phosphorus into coastal waters. The enhanced nutrient export supports nutrient enrichment in coastal waters, can possibly affect the phytoplankton production and composition, leading to eutrophication within nearshore regions of the Madura Strait. Show more

Keywords: Nutrients, budget, eutrophication, biogeochemistry, environmental change, land use, Indonesia

Citation: Asian Journal of Water, Environment and Pollution, vol. 10, no. 1, pp. 73-93, 2013

Authors: Propp, Claudia | Jänen, Ingo | Jennerjahn, Tim

Article Type: Research Article

Abstract: Organic matter (OM) processing in estuaries is crucial in the marine environment as significant quantities of OM are buried or modified in these land-ocean-interaction zones. Southeast Asia is globally important in this regard because of high sediment inputs to the ocean and intense human modifications in the coastal zone, as exemplarily can be observed in the catchment of Java's second largest river, the Brantas. In order to investigate sedimentary OM processing, surface sediments and short sediment …cores were sampled in its estuary in the rainy and dry seasons of 2008. δ^{13} C_{org} , δ^{15} N and C/N ratios as well as amino acids and hexosamines were used to determine the sources, transformation and fate of estuarine sedimentary organic matter. Ranges in δ^{13} C_{org} of −24.9 to −20.1‰, in δ^{15} N of 3.5 to 5.4‰ and a C/N ratio of 7.9 to 16.5 in the sediments indicate a mixture of freshly produced marine algae and degraded terrestrial soil organic matter. The relative contributions of the autochthonous and allochthonous OM in the estuarine sediments differed according to the amount and dispersal of the land-derived material. As the discharge of the two main river arms, the Porong and the Wonokromo River, showed strong differences with upto five-fold higher values in the Porong River in the rainy season, the highest proportion of terrestrial OM was found off the Porong river mouth that received the highest riverine runoff. Also the lowest sedimentary reactivity was detected in this region as displayed by amino acids (AA) and hexosamines (HA). AA+HA ranged between 0.76 and 5.25 mg g^{-1} , amino acid bound carbon between 5.9 and 22.6% and the AA/HA ratio between 4.2 and 13.0. Furthermore, a reduced intensity of OM degradation was observed in front of the Porong River outlet, which has been attributed to the high quantity of deposited material and the low reactivity of the surface sediments. In a global context, the reactivity of sedimentary OM from the Brantas estuary was in the range of degraded sediments from offshore regions or stations at greater water depth. It indicates that severe OM degradation based on a strong tidally induced resuspension of sediments in the turbid and well mixed waters of the shallow Brantas estuary is responsible for burial of refractory carbon. Show more

Keywords: Sediments, organic matter, degradation, stable carbon isotopes, amino acids, Indonesia, Java, Brantas estuary

Citation: Asian Journal of Water, Environment and Pollution, vol. 10, no. 1, pp. 95-115, 2013

Authors: Nugrahadi, Mochamad Saleh | Duwe, Kurt | Schroeder, Friedhelm | Goldmann, Dirk

Article Type: Research Article

Abstract: A Lagrangian particle tracer method embedded within a 3-D finite difference hydrodynamic model is used to study the transport and exchange processes in a semi-enclosed water of Madura Strait, East Java, Indonesia. The 3-D hydrodynamic model forcing functions consist of tidal elevation at north and east open boundary, river discharge of Brantas River estuaries, and monsoonal wind. The validated model successfully estimated the variability of residence time. The calculation results show that water residence times in …Madura Strait and especially in its tributaries are mainly governed by the strength of river discharges, whereas the direction of advection is influenced mainly by monsoon wind directions and less by the tide-induced residual current. Show more

Keywords: Hydrodynamics, water residence time, Lagrangian model, Brantas River, Madura Strait

Citation: Asian Journal of Water, Environment and Pollution, vol. 10, no. 1, pp. 117-128, 2013