Mero Dolakha

Saturday, April 21, 2018

Views Around Pashupatinath Temple in Kathmandu, Nepal

Way to main temple Pashupatinath

Shiva Linga at outside courtyard of the temple

Views at outside of main temple building

Monday, April 16, 2018

Driftwood deposition from debris flows at slit-check dams and fans

Abstract of : Shrestha, B. B., Nakagawa, H., Kawaike, K., Baba, Y. and Zhang, H.: Driftwood deposition from debris flows at slit-check dams and fans, Natural Hazards, Springer, Vol.61, No. 2, pp.577-602, 2012. DOI 10.1007/s11069-011-9939-9
https://link.springer.com/article/10.1007/s11069-011-9939-9

Experience shows that debris flows containing large woody debris (driftwood) can be more damaging than debris flows without driftwood. In this study, the deposition process of debris flows carrying driftwood was investigated using numerical simulations and flume experiments. Debris-flow trapping due to driftwood jamming in a slit-check dam was also investigated. A numerical model was developed with an interacting combination of Eulerian expression of the debris flow and Lagrangian expression of the driftwood, in which the fluctuating coordinates and rotation of the driftwood were treated stochastically. The calculated shapes and thicknesses of a debris-flow fan and the positions and orientations of the deposited driftwood on a debris-flow fan were consistent with experimental flume results. The jamming of driftwood in a slit-check dam was evaluated based on geometry and probability. The simulated results of outflow discharge and the proportion of driftwood passed through the slit-check dam also agreed with the experimental results.

Wednesday, April 11, 2018

Challenges on sediment erosion problem due to Tidal Bore current at Sittaung River Estuary of Myanmar

Lateral bank erosion rate is about more than 3-5km per year. During my one and half hours observation of Tidal bore, the bank was eroded for more than 5m, which is very extreme and challenges to protect the bank erosion.