Glacial lakes in the Nepal Himalaya can threaten downstream communities and have large socio-economic consequences if an outburst flood occurs. This study identified 131 glacial lakes in Nepal in ...2015 that are greater than 0.1 km2 and performed a first-pass hazard and risk assessment for each lake. The hazard assessment included mass entering the lake, the moraine stability, and how lake expansion will alter the lake’s hazard in the next 15–30 years. A geometric flood model was used to quantify potential hydropower systems, buildings, agricultural land, and bridges that could be affected by a glacial lake outburst flood. The hazard and downstream impacts were combined to classify the risk associated with each lake. 11 lakes were classified as very high risk and 31 as high risk. The potential flood volume was also estimated and used to prioritize the glacial lakes that are the highest risk, which included Phoksundo Tal, Tsho Rolpa, Chamlang North Tsho, Chamlang South Tsho, and Lumding Tsho. These results are intended to assist stakeholders and decision makers in making well-informed decisions with respect to the glacial lakes that should be the focus of future field studies, modeling efforts, and risk-mitigation actions.
This paper presents an analysis of a newly developed draft agreement on the allocation of water and energy resources of the Syr Darya basin considering transboundary cooperation and benefits sharing. ...The method uses a river basin model and game theoretic concepts to assess the potential benefits to the four riparian countries, under various arrangements of cooperation, ranging from independent action to full cooperation as envisioned in the draft agreement. The analysis shows increased benefits to all countries in the basin if they follow the four-country cooperative arrangements outlined in the draft agreement. Different methods for allocating the benefits of cooperation are considered. The Shapely allocation provides each country with increased economic benefits and is stable in relation to each country’s likelihood of treaty compliance. Other methods to allocate of the gains are considered, such as proportional shares, equal shares, the Nucleolus, and Nash-Harsayni, which all result in allocations that are more likely to be violated and are less stable than the Shapley allocation. The analysis indicates the upstream country of Kyrgyzstan can be encouraged to participate in and comply with the agreement through additional compensatory payments; however, if their conditions are not right, they may be prone to noncompliance and disruption of the treaty. The concepts illustrated in this paper can be used as the basis for analyzing benefits sharing and cooperation in other transboundary basins.
The Jordan River Basin is experiencing significant water security stress, primarily due to increases in population and agricultural demands. The complex geopolitical dynamics of the region pose ...challenges in collecting field data such as precipitation and evapotranspiration. Consequently, remote sensing data have emerged as indispensable tools for assessing water availability in the basin. The objective of this research study is to utilize data compiled from the water years of 2003 to 2021 to evaluate water availability in the basin. The water flux data, derived from satellite-observed precipitation (Climate Hazards Group InfraRed Precipitation with Station data, CHIRPS) and evapotranspiration (Simplified Surface Energy Balance, SSEBop), offer a comprehensive summary of hydrologic information for each land use class and country. The annual land use maps were acquired from the European Space Agency Climate Change Initiative (ESA CCI). Results indicate an overall rise in evapotranspiration (3.2%) in the basin between the periods of 2003–2011 and 2012–2020. Increased water consumption, particularly in croplands and urban areas (42%), poses a significant future challenge. These findings can guide the development of effective water resource management policies to enhance water security in a region that is vulnerable to the impacts of climate change.
Glacier outburst floods with origins from Lhotse Glacier, located in the Everest region of Nepal, occurred on 25 May 2015 and 12 June 2016. The most recent event was witnessed by investigators, which ...provided unique insights into the magnitude, source, and triggering mechanism of the flood. The field assessment and satellite imagery analysis following the event revealed that most of the flood water was stored englacially and that the flood was likely triggered by dam failure. The flood's peak discharge was estimated to be 210 m3 s−1.
Glacial retreat causes the formation of glacier lakes with the potential of producing glacial lake outburst floods (GLOFs). Imja Lake in Nepal is considered at risk for a GLOF. Communities in the ...path of a potential Imja GLOF are implementing adaptation projects, yet no quantitative data or guidance is available to understand the benefits of these projects or how to weigh benefits against the cost of implementation. We develop and demonstrate a decision-making methodology for GLOF risk management, incorporating available scientific information and uncertainty. The methodology consists of (1) identifying flooding scenarios, (2) evaluating scenario consequences, and (3) performing an economic analysis of proposed adaptation projects. The methodology is applied to assess benefits in Dingboche of lowering Imja Lake by 3, 10 and 20 m. The results show that the baseline case (no lake lowering) has the lowest expected cost because of low valuation of agricultural land and homes in the literature. Nonetheless, the result is sensitive to changes in the analysis variables. We also found that lowering the lake by 10 or 20 m is efficient according only to the methodology used here; however, considering only direct economic damages and literature cost estimates, the costs outweigh the benefits for these projects.
In recent decades, many of the larger glaciers in the Himalaya and Andes that have experienced increased melting have become glacial lakes. Some of these lakes present a risk of glacial lake outburst ...floods that can unleash stored lake water and eroded debris, often causing enormous devastation downstream. Many of these new glacial lakes have formed in the Mt. Everest and Makalu Barun National Parks of Nepal, nine of which in the remote Hinku and Hongu valleys have been designated as “potentially dangerous” based on remote sensing analyses. Until recently, however, relatively little ground-based information was available for these lakes, including their physical characteristics, danger level, prospective downstream impacts in the event of an outburst, and mitigation methods appropriate and applicable to remote regions within the Nepal Himalaya. This paper describes three separate, interdisciplinary expeditions to the Hinku and Hongu valleys between 2009 and 2012 that were designed to close these information gaps. Each expedition combined remote sensing with field-based analyses, repeat photography, interviews with local people, bathymetric surveys, ground penetrating radar, and flood modeling. Eight of the “potentially dangerous” lakes surveyed were found to be stable, and one that had escaped mention in previous studies (L464) was found to contain a high risk of an outburst flood. In the data-deficient high mountain world, we suggest that the combined use of sophisticated remote sensing and modeling technologies with traditional, field-based methods can provide the most thorough understanding of glacial lakes possible at this time, including the actual risks that they pose as well as the most appropriate and community-based risk reduction strategies.
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