The Effect of Gate Existence at L Islandon The Seabed Profile Due to Reclamation of Jakarta Bay

Diatas Lake is one of the five lakes in the Province of West Sumatra, that requires special attention for its sustainability. A numerical hydrodynamic model of Diatas Lake is presented to observe the biochemical oxygen demand (BOD), sulphide, chemical oxygen demand (COD), dissolved oxygen (DO), phosphate and total suspended sediment (TSS). The model used the surface-water modeling system (SMS), developed by the US Army Corps of Engineers. Field data acquisition, such as bathymetry, water level, and lake current velocity are carried out. The water samples are also collected. The model validation shows good agreement between field and model data. The water quality model is used to simulate the distribution of BOD, sulphide, COD, DO, phosphate and TSS concentration for one year. At the end of the simulated year, the BOD, COD, DO, phosphate and TSS concentration are still within a safe range, in accordance with the environmental government regulation. However, the sulphide concentration exceeds the safe regulatory range. For long-term environmental lake conservation, the use of fertilizer should be regulated and enforced.

Section: Numerical Modelmentioning

confidence: 99%

Modeling the Spatial Concentration Distribution of Environmental Parameters and Total Suspended Sediment in Diatas Lake, Western Sumatra, Indonesia

Wurjanto¹

2019

“…This tool had been widely used in the world for various applications. Ajiwibowo and Pratama (2017) [7,8] and Ajiwibowo (2018) [9] used the tools in the study of Ancol of Indonesia reclamation in Jakarta Bay and Muan river modeling in East Kalimantan, respectively.…”

Section: Numerical Modelmentioning

confidence: 99%

Assessment of Hydro-Environmental Condition Using Numerical Modeling in Dibawah Lake, Western Sumatra, Indonesia

Ajiwibowo¹

2018

Self Cite

This study investigates the hydro-environmental condition of Dibawah Lake, Province of Western Sumatra, Indonesia, using a finite element model called the Surface-water Modeling System (SMS). The aim is to present the parameters distribution in the existing condition and a year later. Field measurements are carried out to supply data for the domain input, boundary conditions, and model validation. The field measurements are lake-bed elevation, water level, current flow, and contaminant quantity measurements. The contaminant measurements are carried out to collect biochemical oxygen demand (BOD), sulfide, and total suspended sediment (TSS). The existing flow model is validated by current flow and water elevation field data. The validation shows a decent agreement. The result of water quality modeling, using the water quality module of SMS called RMA4, shows that after a year the BOD content is still in an acceptable proportion, which is less than 2 mg/liter. However, it is found that the sulfide content exceeds the limit defined by the government regulation, at over 0.002 mg/liter. In the sedimentation model generated by the module in SMS called SED2D, the maximum bed change obtained is around 15 cm, located at the inlet of two rivers connected to the lake. The proposed mitigation of the current research findings is to control the use of fertilizer around the lake watershed area with the aim of lowering the sulfide content and to maintain the lake bed elevation by routine dredging, particularly in the river inlets.

“…The tidal current field measurement refers to research result by Ajiwibowo et al (2017) [12]. The two black pins (L3 and L4) in Fig.…”

Section: Tidal Current Field Measurementmentioning

confidence: 99%

“…The influence of the artificial islands and the existence of the gate is investigated using hydrodynamic modeling. The model setup refers to previous research result done by Ajiwibowo et al (2017) [12]. Fig.…”

Section: Model Setupmentioning

confidence: 99%

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The Influence of the Jakarta Bay Reclamation on the Surrounding Tidal Elevation and Tidal Current

Ajiwibowo¹,

Pratama²

2018

Self Cite

The Jakarta Bay artificial island reclamation is a part of the spatial arrangement of the Province of DKI Jakarta which is stated in Governor Regulation No. 121/2012. The regulation divides the area into three sub-regions, west, middle and east. In the middle sub-region, the influence of the reclamation of artificial islands, named I, J, K, L and M islands, on the tidal elevation and tidal current is investigated using hydrodynamic modeling with inputs of the river discharges coming into the bay. The plan to build a gate at the southern side of L island is also a part of the study. For normal river discharge, the existence of the reclaimed islands does not influence the tidal elevation significantly, whereas the tidal current is affected by a 200% intensification at a few points. For flood river discharge with a 25-year return period, the tidal elevation is more unstable, with the maximum rising or falling by 2 cm at most locations. The current phase shift is found, and along with the current intensification of round 200%, there is a reduction of the current magnitude. The reclamation and the gate cause some tidal changes, although these are still within the normal range that can accommodate daily activities. The reclamation scenario with the gate is better for the channel at the eastern side of L island since it results in a lower tidal elevation.