Drainage in peatland caused reducing water storage and subsidence. Groundwaterlevel fluctuations are a major role in the water balance that occurs in peatlands. Theresearch was conducted in a specific area of agricultural peatland. The location inSub-Peatland Hydrological Unit (Sub- PHU) 5 and 6 Kahayan Sebangau, CentralKalimantan Province, Indonesia. Modeling for groundwater table was applied usingFreewat / Modflow software with input rainfall probability 80% (R80), infiltration,and evapotranspiration data analysis. Groundwater table should not be less thanminus 0.4 meters based on the Indonesian Ministry of Environment and Forestry(Menlhk). The deficit means the groundwater level below -0.4 m and surplus uponthe criteria. Land modeling is simulated with an area of 300 x 1000 meters. Thecalibration in the model was found conductivity values, 50 m / day or 5.78 x 10-4 m /s with the best value with the largest NSE and Correlation. The modeling showedthat the deficit occurred in seven months. The groundwater management is how tokeep the water level upon -0.4 m with the planning of canal blocking height. Thescenarios are 0.2 m. 0.3 m, 0.4m, and 0.5 m upon the base flow of the canal. Thebest scenario was chosen 0.5m according to the simulation which has the waterlevel upon -0.4 m.

This research discussed the effect of scouring on the stability of the slope on the Bujangga street STA 00+000 sd STA 00+075. A landslide had occurred in the development of a road located on the Bujangga riverside. The road is the result of widening which was previously only 2 lanes with a width of 8 m to 4 lanes with a width of 20 m. Landslides occured at STA 00+000 up to STA 00+075. At the STA the road experiences a landslide in the direction of the river to the elevation of the road surface down as deep as ± 2m. This research type is survey. Data was collected with documentation of post-landslide soil investigations, investigation of landslide conditions in the field, and sheet-pile slip simulation using the finite element method with helping the PLAXIS V.7.2 program. Data analysis with descriptive and back analysis to input soil parameters produces deformation and landslide mechanism that is relevant to actual conditions in the field. As a result of scouring of the river there is a reduction in passive pressure on the outside of the sheetpile which results in a decrease in the value of the safety factor of the road including other buildings such as settlements. This is indicated by the results of modeling and simulation above which gives the value of FS=1.2602 without scouring and FS=1.045 after scouring. The scouring of the river can be concluded that on a long-term scale the location is a landslide prone location.Keywords: Landslide Analysis, Finite Element, Road Development, Riverside  Penelitian ini membahas pengaruh scouring terhadap stabilitas lereng pada kelongsoran Jalan Bujangga STA 00+000 sd STA 00+075. Pernah terjadi kelongsoran pada pengembangan jalan yang berlokasi di pinggiran sungai Bujangga. Jalan tersebut merupakan hasil pelebaran yang sebelumnya hanya 2 lajur dengan lebar 8 m menjadi 4 lajur dengan lebar 20 m. Kelongsoran terjadi pada STA 00+000 sampai dengan STA 00+075. Pada STA tersebut jalan mengalami kelongsoran ke arah sungai hingga elevasi permukaan jalan turun sedalam ± 2m. Penelitian ini berjenis survey. Data dikumpulkan dengan dokumentasi penyelidikan tanah pasca longsoran, investigasi kondisi longsoran di lapangan, dan simulasi kelongsoran sheetpile menggunakan metode elemen hingga dengan bantuan program PLAXIS V.7.2. Analisis data dengan deskriptif dan back analysis hingga parameter tanah input menghasilkan deformasi dan mekanisme kelongsoran yang relevan dengan kondisi actual di lapangan. Akibat dari scouring atau gerusan sungai terjadi pengurangan tekanan pasif pada sisi luar sheetpile yang berakibat penurunan nilai faktor keamanan dari jalan termasuk bangunan lain seperti pemukiman. Hal tersebut ditunjukkan oleh hasil pemodelan dan simulasi di atas yang memberikan nilai FS=1.2602 tanpa scouring dan FS=1.045 setelah adanya scouring. Adanya gerusan pada bibir sungai dapat disimpulkan bahwa dalam skala jangka panjang lokasi tersebut merupakan lokasi rawan bencana longsoran.Kata Kunci: Analisis Longsoran, Elemen Hingga, Pengembangan Jalan, Pinggiran Sungai

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This research was carried out in inundation that occurred in the Port area of Dobo City, Aru Islands Regency. Inundation that occurs is due to the unavailability of adequate and well-arranged drainage. This research aims to plan a drainage system in the Port area of Dobo City that can overcome the inundation that arises and the influence of tides. Data processing is carried out with two analyzes including hydrological analysis and hydraulic analysis. For hydraulics analysis, this includes cross section planning and drainage system modeling with HEC-RAS 4.0. In conventional drainage in the case of high tides, the results of the modeling show that the overflow of water on the channel that will occur is at an elevation of +2.48 m. After adding a long storage with dimensions of 1.2 m x 3.5 m along 101.6 m and sea walls as high as + 2.48 m. The results of the modeling show that the inundation height that will occur is at an elevation of +0.61 m. Of the several scenarios that are performed for the most optimal two-door openings, which are opened by 30 cm which later the water will be at + 12 cm elevation. Whereas the most optimal one-door openings are opened by 70 cm which later the water will be at + 6 cm elevation.

AbstractThis paper presents numerical analyses of an excavation using stress path dependent soil parameters, where soil elements in a region of the excavation are represented by specific soil parameters that correspond to their specific stress paths. The performance of the M1 excavation pit in Berlin sand was selected as the analysed case. This excavation pit was supported by diaphragm-wall with a single row of pre-stressed anchors. The numerical analyses of the excavation were performed using finite element program PLAXIS 3D. Mohr-Coulomb model and Hardening Soil model were used as the soil constitutive models. The analyses were performed using two approaches, which are: (i) analysis using axial compression soil parameters, and (ii) analysis using stress path dependent soil parameters. A set of conversion ratios were employed to convert the general soil parameters (i.e. axial compression stress path) to the soil parameters of the other stress paths. These conversion ratios were obtained from an experimental program of true triaxial tests conducted on Bangka sand. The comparison of the field records and the analysis results were discussed. The results show that the stress path dependent approach produced better prediction of diaphragm-wall deformation compare to the general approach using axial compression soil parameters.