A comparison of wood-sediment-water mixture flows at a closed type and an open type of check dams in mountain rivers

The debris flow event in Hofu City, Yamaguchi Prefecture, Japan on July 21, 2009 yielded a large amount of sediment transport and woody debris in the mountain river basin, where a closed type of check dam and an open type of check dam were built (Maricar et al., 2011). Based on laboratory tests, the debris flow control by these check dam was studied. This paper compares the deposition process of sediment grains and pieces of wood at the open and closed check dam in a laboratory flume experiment. The experimental results showed that the open check dam trapped the wood pieces and the trapped pieces deposited the sediment grains behind themselves. On the other hand, the closed check dam made most of wood pieces pass through the check dam and most of sediment grains get trapped in the water pool behind the closed check dam

Upaya Mengurangi Angkutan Sedimen Sungai Garang Kota Semarang

West floodway Semarang city is one of the infrastructure for manage flood in Garang Stream. Because of sedimentation in Garang stream, decrease flow capacity. Check Dam construction is made beam for help reduce river slope so can decrease water velocity and reduce capacity sediment delivery in Garang stream. Build check dam will reduce sedimentation in downstream Garang river. From calculation fall of rain in years with Thiessen method then do hidrology analyze using HEC-HMS and get rate of flood 100 years in location in the amount of 386.9 m3/det. Analyze using USLE method get erotion number amount 1.85 mm/year (32.01 ton/ha/year), and form erotion analyze get number of sedimentation amount 2.677 ton/ha/year. Location of Pramuka check dam construction is in downstream Pramuka bridge, Pudak Payung, Semarang. With planning as following: high physical effective main dam is 4 m, depth of foundation is 1.3 m, material for buil check dam is form river rocks. Implementation check dam works need 6 month and cost two billion eight hundred ninety five thousands million rupiah(Rp 2,895,000,000)

Hydrologic and cost-benefit analysis of multiple check dams in catchments of ephemeral streams, Rajasthan, India

Investment in the small-scale enhancement of groundwater recharge through check dams and other recharge structures in rural India is on the order of USD 1 billion/year. However, for any catchment, the optimal capacity of check dams is unknown, and the impacts on downstream flows are rarely determined. This paper describes a method that can be applied to plan recharge augmentation in catchments that have at least one monitored check dam. It was applied in the Dharta catchment of the Aravalli Hills in Udaipur district, Rajasthan, India, where four check dams in an ephemeral stream were monitored by farmers over seven years. For the last three years of this study, the hydrology of two of these check dams was affected by 19 new check dams established upstream. A basic hydrologic model, WaterCress, was calibrated on monitored check-dam storages and used to assess the impacts of the new structures on recharge from those downstream. Then, the model was rerun with a range of capacities of upstream check dams to determine the effects of check-dam capacity on (1) the recharge from the downstream check dam, (2) the total recharge from all check dams, and (3) the frequency of spill from the downstream check dam. Using the available economic information, the benefit–cost ratio was calculated for a range of check-dam capacities. This showed a decline in economic efficiency with each new check dam and defined the optimal capacity. Monsoon size was found to be consequential to results, and longer hydrological records yield more reliable results. The study showed that monitoring check dams, rainfall, and groundwater levels is key to deciding whether additional check dams are economically beneficial

ANALISA PERILAKU LAJU SEDIMENTASI TERHADAP CHECK DAM SERIES PADA BATANG KURANJI SEGMEN TENGAH MENGGUNAKAN SOFTWARE HEC-RAS 6.0.0

Batang Kuranji segmen tengah merupakan sungai yang berada pada Daerah Aliran Sungai (DAS) Batang Kuranji yang terletak di Kota Padang. Batang Kuranji segmen tengah memiliki kemiringan dasar sungai yang sangat tinggi sehingga menyebabkan tingginya pergerakan sedimen pada dasar sungai. Pada Batang Kuranji segmen tengah ini telah dibangun sebanyak empat buah check dam untuk mengurangi besarnya gerusan yang terjadi. Akan tetapi, penumpukan sedimen masih terlihat pada hulu dan hilir masing-masing dari ke-empat check dam tersebut berada. Berdasarkan hal tersebut, maka dilakukan penelitian tentang perilaku laju sedimentasi terhadap keberadaan beberapa check dam (check dam series) dengan menggunakan berbagai metode transpor sedimen yang terdapat pada software HEC-RAS 6.0.0. yang terdapat pada HEC-RAS yaitu metode Ackers-White, Engelund-Hansen, Laursen (Copeland), Meyer Peter Muller, Toffaleti, MPM-Toffaleti, Yang, dan Wilcock-Crowe. Hasil analisa terendah dengan adanya check dam dan tanpa check dam diperoleh dengan metode Meyer Peter Muller. Terdapat 3 jarak yang berbeda pada check dam series ini, yaitu J1 (jarak antara check dam 1 ke check dam 2), J2 (jarak antara check dam 2 ke check dam 3), dan J3 (jarak antara check dam 3 ke check dam 4). Berdasarkan simulasi yang dilakukan terhadap ke-empat check dam tersebut dapat disimpulkan bahwa laju sedimentasi dengan adanya check dam bernilai lebih kecil daripada laju sedimentasi tanpa adanya check dam namun, hal ini hanya berlaku pada titik dimana masing- masing check dam tersebut berada. Laju sedimentasi dengan adanya check dam di titik yang terletak pada sebelum dan sesudah check dam berada memiliki nilai yang sama bahkan lebih besar daripada nilai laju sedimentasi tanpa adanya check dam

Construction of Check Dam in Microwater-Shed Areas in Tundi Block of District Dhanbad, Jharkhand

This paper envisages the ecological and civil engineering aspect of check-dam construction in a micro watershed environment for preventing possible soil erosion and silt wastage due to strong current by small streams or river tributaries. The field study was done for checking the feasibility of construction of check-dam over Keshka River, in Tundi block of district Dhanbad, Jharkhand. The physical, ecological, social and economic factors were also noticed during the evaluation of the check-dam. It was observed that the river tributary at Keshka had one of the most unpredictable water current and thus, a proposed check-dam would , firstly, check any abrupt increase in the water flow in the this area. Secondly, due to the strong current of the river, the gully erosion is quite heavily prevalently noticed in the area which can further lead to the decrement of soil quality and basic soil texture, due to silt wastage. Also, considering the ecological aspect, the water if controlled can be used in the near-by irrigation purpose, through which farmers having their land(s) adjoining to the proposed check-dam, would have a high moisture content, and thus, they could enhance the soil water percolation rate of their soil, and on an overall scenario, the ecological aspects also can be enhanced of this area.Further, this will increase ground water level in nearby areas through quick recharge of drinking as well as irrigation wells

Fenomena Transport Sedimen disaluran terhadap Perubahan Jarak Check Dam Series

Penelitian ini merupakan peniruan terhadap pola aliran melalui check dam series dan sedimentasi antar check dam. Check dam series yang dipakai adalah check dam pada Batang Kuranji dan check dam Kali Woro. Model dibuat dengan menggunakan pendekatan terhadap kondisi yang ada dengan tinggi dam skala 1:125 sedangkan jarak check dam 1:300 adapun jarak kondisi lapangan antara check dam skenario 1 (89,00 cm), skenario 2 (94,00 cm), skenario 3 (200 cm). Semua model dilakukan pada saluran terbuka segiempat 40 x 40 cm di laboratorium Mekanika Fluida dan Hidrolika, Fakultas Teknik Universitas Andalas, Padang. Material sedimen digunakan dari Batang Kuranji. Selanjutnya setiap percobaan dengan variasi debit aliran diamati dan diukur pola sebaran sedimen di sebelum dan sesudah bangunan check dam. Dari hasil pengujian yang dilakukan, didapatkan kondisi seimbang sedimen berkisar antara 10-19 menit setelah air keluar dari dainhole. Pemakaian jarak 94 cm efektif digunakan pada check dam 1 dan 2 dapat mengurangi gerusan dan check dam 3 mempertahankan dinding saluran. Volume sedimen bergerak lebih besar pada jarak check dam skenario 3 pada bangunan check dam 3 debit 2,25 l/s sedimen bergerak 68,2%. Variasi debit mempengaruhi kedalaman gerusan. Semakin besar debit dan semakin jauh jarak antar check dam semakin besar pergerakan sedimen

Perencanaan Check Dam Sungai Dawe Kudus

Juana river's located in two administrative regions Kudus and Pati had superficial. This is because the slope of the river is quite gentle and the level of environmental degradation in the watershed (DAS) Juana river's have increased. Based on these conditions, it is necessary to plan the construction of sediment control (check dams) to reduce sedimentation along the river and optimize the function of the Juana river's. Planning is performed on Dawe river's ,the branch of Juana river's. From the calculation results obtained 7 m high main dam, main dam foundation depth of 2,8 m, width of crest main dam 32 m, the water level above the crest 1,60 m, high freeboard 0,6 m, thick of main dam crest wing 2 mand capacity of sediments for 20.851,063 m³. The total cost needed to build the check dam Dawe river's is Rp. 6.511.846.000,00 already includes VAT and 23 weeks old craftsmanship

PERENCANAAN CHECK DAM SEBAGAI BANGUNAN PENGENDALI SEDIMEN DI SUNGAI AIH TRIPE, DESA TELPI, KABUPATEN GAYO LUES

Kelestarian Daerah Aliran Sungai (DAS) bergantung pada hijaunya tumbuhan dan pepohonan di hutan sekitarnya. Kerusakan hutan yang parah akan mempengaruhi laju erosi dan berdampak pada bertambahnya volume sedimen di sungai. Lokasi perencanaan dilakukan di Sungai Aih Tripe kawasan Desa Telpi, Kecamatan Blangkejeren, Kabupaten Gayo Lues, Provinsi Aceh. Tampungan di sungai kawasan ini telah mengalami penurunan volum yang diakibatkan oleh sedimen yang menumpuk. Jika terjadi debit tinggi akan mengakibatkan meluapnya air sungai ke daerah pemukiman di sekitar sungai. Penelitian ini bertujuan untuk mendesain konstruksi bangunan Check dam yang akan bermanfaat untuk menahan dan menampung sedimen yang terjadi serta mencegah air melimpah ke daerah pemukiman pada saat debit tinggi. Rencana metode penelitian ini yaitu dengan memperkirakan nilai erosi lahan yang terjadi dengan menggunakan rumus Universal Soil Loss Equation (USLE). Selanjutnya menghitung nilai Sediment Delivery Ratio (SDR) untuk mengetahui besarnya persentase erosi yang akan masuk ke dalam sungai. Data hujan didapatkan dari 2 stasiun BMKG yaitu di Takengon dan Blangkejeren dengan jumlah data yaitu 10 tahun. Data hujan tersebut dilakukan analisis frekuensi dengan pengujian beberapa metode, yaitu metode normal, log normal, gumbel dan log pearson III. Tahap akhir didesain konstruksi dengan menggunakan debit banjir periode ulang 20 tahun yaitu sebesar 240,16 m3/det yang dihitung dengan metode Haspers. Konstruksi check dam direncanakan pada cross sta 0 + 000 dengan tinggi mercu 2 m dan lebar pelimpah bagian bawah sebesar 65 m. Dari hasil perhitungan perencanaan didapatkan erosi lahan yang terjadi sebesar 42587,17 m3/tahun dan kapasitas tampungan bangunan check dam sebesar 74285,71 m3. Dengan kedua nilai tersebut dapat diketahui waktu tampungan check dam akan penuh selama 1,74 tahun.Kata kunci : Check dam, erosi lahan, SDR, Gayo Lue