Abstract. In Nepal and many developing countries around the world, roads are vehicles for development for communities in rural areas. By reducing travel time on foot, opportunities are opened for quicker transportation of goods and better access to employment, education, health care and markets. Roads also fuel migration and numerous social changes, both positive and negative. Poorly constructed roads in mountainous areas of Nepal have increased erosion and landslide risk as they often cut through fragile geology, destabilizing slopes and altering local hydrological conditions, with costs to lives and livelihoods. The convergence of the newly constituted decentralized Nepali government with China's Belt and Road Initiative is likely to bring more roads to rural communities. The new provincial government administrations now have the opportunity to develop policies and practices, which can realign the current trend of poorly engineered, inefficient and hazardous road construction toward a more sustainable trajectory. This commentary provides an overview of some of the obstacles along the way for a more sustainable road network in Nepal and illustrates how good governance, development and landslide risk are intertwined. The opinion presented in this brief commentary lends little hope that Nepal's current pathway of unsustainable road construction will provide the country with the much-needed sustainable road network, unless checks and balances are put in place to curb noncompliance with existing laws and policies.
Intense monsoonal rain is one of the major triggering factors of floods and mass movements in Nepal that needs to be better understood in order to reduce human and economic losses and improve infrastructure planning and design. This phenomena is better understood through intensity-duration-frequency (IDF) relationships, which is a statistical method derived from historical rainfall data. In Nepal, the use of IDF for disaster management and project design is very limited. This study explored the rainfall variability and possibility to establish IDF relationships in data-scarce situations, such as in the Central-Western hills of Nepal, one of the highest rainfall zones of the country (~4500 mm annually), which was chosen for this study. Homogeneous daily rainfall series of 8 stations, available from the government’s meteorological department, were analyzed by grouping them into hydrological years. The monsoonal daily rainfall was disaggregated to hourly synthetic series in a stochastic environment. Utilizing the historical statistical characteristics of rainfall, a disaggregation model was parameterized and implemented in HyetosMinute, software that disaggregates daily rainfall to finer time resolution. With the help of recorded daily and disaggregated hourly rainfall, reference IDF scenarios were developed adopting the Gumbel frequency factor. A mathematical model [i = a(T)/b(d)] was parameterized to model the station-specific IDF utilizing the best-fitted probability distribution function (PDF) and evaluated utilizing the reference IDF. The test statistics revealed optimal adjustment of empirical IDF parameters, required for a better statistical fit of the data. The model was calibrated, adjusting the parameters by minimizing standard error of prediction; accordingly a station-specific empirical IDF model was developed. To regionalize the IDF for ungauged locations, regional frequency analysis (RFA) based on L-moments was implemented. The heterogeneous region was divided into two homogeneous sub-regions; accordingly, regional L-moment ratios and growth curves were evaluated. Utilizing the reasonably acceptable distribution function, the regional growth curve was developed. Together with the hourly mean (extreme) precipitation and other dynamic parameters, regional empirical IDF models were developed. The adopted approach to derive station-specific and regional empirical IDF models was statistically significant and useful for obtaining extreme rainfall intensities at the given station and ungauged locations. The analysis revealed that the region contains two distinct meteorological sub-regions highly variable in rain volume and intensity.
The tsunamis on 26 December 2004 and 28 March 2005 killed only 7 people on Simeulue Island in Indonesia's Aceh province. At Langi, on the north end of Simeulue, which is 40 km south of the December earthquake's epicenter, maximum wave heights exceeded 10 m less than 10 minutes after the shaking ceased. In the more populous south, wave heights averaged 3 m and caused significant structural damage, destroying entire villages. Oral histories recount a massive 1907 tsunami and advise running to the hills after “significant” shaking (∼1 minute). All the interviewed Simeulue survivors knew of this event and of the necessary action. However, Jantang, on the Aceh mainland, suffered far more casualties. Simeulue's oral history provided an extraordinarily powerful mitigation tool that saved countless lives where even a high-tech warning system with a 15-minute response time would have been of no help.
Padang, West Sumatra, Indonesia is considered to have one of the highest tsunami risks in the world. Currently, the strategy to prepare for a tsunami in Padang is focused on developing early warning systems, planning evacuation routes, conducting evacuation drills, and educating the public about its tsunami risk. Although these are all necessary efforts, they are not sufficient. Padang is located so close to the Sunda Trench and has such flat terrain that a large portion of its populace will not be able to reach safe ground in the interval—less than 30 minutes—between the time the earthquake shaking stops and the tsunami arrives at the shore. It is estimated that over 100,000 inhabitants of Padang will be unable to evacuate in that time, even if they head for safe ground immediately following the earthquake. Given these circumstances, other means to prepare for the expected tsunami must be developed. With this motivation, GeoHazards International and Stanford University partnered with Indonesian organizations— Andalas University in Padang, the Laboratory for Earth Hazards (LIPI), and the Ministry of Marine Affairs and Fisheries (KKP)—in an effort to evaluate the need for and feasibility of developing Padang’s tsunami evacuation infrastructure. This project team designed and conducted a course at Stanford University, undertook several field investigations in Padang, and participated in a reconnaissance trip following the September 30, 2009 earthquake. The team concluded that: 1) the tsunami-generating earthquake is still a threat, despite the recent M7.6 earthquake; 2) Padang’s tsunami evacuation capacity is currently inadequate, and evacuation structures need to be implemented as part of an effective evacuation plan; 3) it is likely that previous estimates of the number of people unable to evacuate in time are grossly low; and 4) a more engineering-based approach is Project Manager, GeoHazards International, Palo Alto, CA 94301 2 Graduate Student, Dept. of Civil Engineering, Stanford University, Stanford, CA 94305 3 Professor, Dept. of Civil Engineering, Stanford University, Stanford, CA 94305 4 Project Engineer, Tipping Mar, Berkeley, CA 94704 5 Professor, Dept. of Civil Engineering, Andalas University, Padang, Indonesia 6 Graduate Student, Dept. of Civil Engineering, Andalas University, Padang, Indonesia needed to evaluate the appropriateness of existing buildings to serve as evacuation sites.
