Abstract. This paper presents the simulation of floodplain at Musi River using integrated 1D and 2D hydrodynamic model. The 1D flow simulation was applied for the river channel with flow hydrograph as upstream boundary condition. The result of 1D flow simulation was integrated into 2D flow simulation in order to know the area and characteristics of flood inundation. The input data of digital terrain model which was used in this research had grid resolution of 10mx10m, but for 2D simulation the resolution was with grid resolution 50 m x 50 m so as to limit simulation time since the model size was big enough. The result of the simulation showed that the inundated area surrounding Musi River is about 107.44 km 2 with maximum flood depth is 3.24 m, water surface velocity ranges from 0.00 to 0.83 m/s. Most of floodplain areas varied from middle to high flood hazard level, and only few areas had very high level of flood hazard especially on river side. The structural flood control measurement to be recommended to Palembang is to construct flood dike and flood gate. The non structural measurement one is to improve watershed management and socialization of flood awareness.
Indonesia is rich in endemic species of flora and fauna. One of them is Ornithoptera croesus butterfly, which is endemic to North Maluku. Habitat degradation and trade of this species have caused the populations to decline. To avoid the collection of butterfly specimens from nature and to preserve their habitat and population in nature, a semi-natural butterfly breeding practice at Bacan Island was initiated in 2013. This research was conducted to assess the breeding approach for O. croesus lydius using a qualitative descriptive method. The assessment was based on these variables: the specific ecology of the butterfly; the suitability of the breeding site and development model; the utilization of larval host plants and butterfly nectar plants; and the establishment of the birdwing population at the site. The observations and results are presented here. Based on the assessment, the in-situ semi-natural breeding approach is one of the solutions for sustainable use of this protected species.
This paper deals with the modelling and simulation of flood inundation characteristics i.e. boundaries, depths, and velocities within Sekanak Subsystem which is one of flood-prone areas in Palembang City, Indonesia. The area of subsystem being studied was about 11 km 2. The new hydrodynamic model, HEC-RAS 5.0 was used to simulate the flood flow regimes by integrating the one-dimensional and two-dimensional model, known as combined 1D/2D flow model. The geometry of drainage channel was used as 1D domain to simulate the flow routing along the channel based on certain boundary conditions i.e. 25-yrs flood discharge and tide level both in upstream and downstream. The 2D domain in the model was the geometry of area beside the channel. The flow of 1D and 2D domain were connected by lateral weir, so the water which overflowing from the channel could be routed within 2D areas. The result shows that the area of inundation during lowest tide level is about 3.43 km 2 with the velocities and depths range between 0-1.18 m/s and 0-3.08 m respectively. Furthermore, for average tide level, the area of inundation increases to 3.54 km 2 with the velocities and depths range between 0-1.30 m/s and 0-3.11 m respectively. The maximum potential of inundation during the highest tide level is about 4.46 km 2 with the velocities and depths respectively range between 0-2.64 m/s and 0-3.40 m. Therefore, it can be concluded that almost half of subsystem area potentially being inundated (40.11%), so it requires appropriate flood control and management to reduce the risk.
Wing patterns of female Elymnias agondas (Boisduval, 1832) butterflies are highly variable, presumably to mimic different Taenaris species throughout New Guinea and surrounding islands. Labels on most E. agondas museum specimens lack precise locality information, complicating efforts to match E. agondas female wing patterns with presumed Taenaris model species. This paucity of data also makes it impossible to determine where different forms occur and whether they are strictly allopatric. During fieldwork on the Aru Archipelago, we found two distinct forms of E. agondas females occurring syntopically. The “light form” resembles T. catops, while the “dark form” seems to mimic T. myops and T. artemis. We discuss the significance of this finding and illustrate species in the Taenaris mimicry ring encountered on Aru.
We present new data on the geographical distribution of 16 species of diving beetles collected by an Indonesian citizen scientist in Bali. Copelatus oblitus Sharp, 1882, C. regimbarti Branden, 1884, C. sumbawensis Régimbart, 1899, and Hydroglyphus laeticulus (Sharp, 1882) are recorded for the first time from the island. We summarize what is known about the species’ distributions and habitats in Indonesia and beyond, and provide distribution maps and photographs of the sampling sites and habitus of the species. This work serves as a best practice template between individual local citizen scientists with local and international scientists.
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