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The Himalayas of South Asia are home to many glaciers that are retreating due to climate change and causing the formation of large glacial lakes in their absence. These lakes are held in place by naturally deposited moraine dams that are potentially unstable. Specifically, an impulse wave generated by an avalanche or landslide entering the lake can destabilize the moraine dam, thereby causing a catastrophic failure of the moraine and a glacial lake outburst flood (GLOF). Imja-Lhotse Shar Glacier is amongst the glaciers experiencing the highest rate of mass loss in the Mount Everest region, in part due to the expansion of Imja Tsho. A GLOF from this lake may have the potential to cause catastrophic damage to downstream villages, threatening both property and human life, which prompted the Nepali government to construct outlet works to lower the lake level. Therefore, it is essential to understand the processes that could trigger a flood and quantify the potential downstream impacts. The avalanche-induced GLOF process chain was modeled using the output of one component of the chain as input to the next. First, the volume and momentum of various avalanches entering the lake were calculated using Rapid Mass Movement Simulation (RAMMS). Next, the avalanche-induced waves were simulated using the Basic Simulation Environment for Computation of Environmental Flow and Natural Hazard Simulation (BASEMENT) model and validated with empirical equations to ensure the proper transfer of momentum from the avalanche to the lake. With BASEMENT, the ensuing moraine erosion and downstream flooding was modeled, which was used to generate hazard maps downstream. Moraine erosion was calculated for two geomorphologic models: one site-specific using field data and another worst-case based on past literature that is applicable to lakes in the greater region. Neither case resulted in flooding outside the river channel at downstream villages. The worst-case model resulted in some moraine erosion and increased channelization of the lake outlet, which yielded greater discharge downstream but no catastrophic collapse. The site-specific model generated similar results, but with very little erosion and a smaller downstream discharge. These results indicated that Imja Tsho is unlikely to produce a catastrophic GLOF due to an avalanche in the near future, although some hazard exists within the downstream river channel, necessitating continued monitoring of the lake. Furthermore, these models were designed for ease and flexibility such that local or national agency staff with reasonable training can apply them to model the GLOF process chain for other lakes in the region.

One of the consequences of recent glacier recession in the Cordillera Blanca, Peru, is the risk of glacial lake outburst floods (GLOFs) from lakes that have formed at the base of retreating glaciers. GLOFs are often triggered by avalanches falling into glacial lakes, initiating a chain of processes that may culminate in significant inundation and destruction downstream. This paper presents simulations of all of the processes involved in a potential GLOF originating from Lake Palcacocha, the source of a previously catastrophic GLOF on 13 December 1941, killing about 1800 people in the city of Huaraz, Peru. The chain of processes simulated here includes (1) avalanches above the lake; (2) lake dynamics resulting from the avalanche impact, including wave generation, propagation, and run-up across lakes; (3) terminal moraine overtopping and dynamic moraine erosion simulations to determine the possibility of breaching; (4) flood propagation along downstream valleys; and (5) inundation of populated areas. The results of each process feed into simulations of subsequent processes in the chain, finally resulting in estimates of inundation in the city of Huaraz. The results of the inundation simulations were converted into flood intensity and preliminary hazard maps (based on an intensity-likelihood matrix) that may be useful for city planning and regulation. Three avalanche events with volumes ranging from 0.5 to 3 × 106 m3 were simulated, and two scenarios of 15 and 30 m lake lowering were simulated to assess the potential of mitigating the hazard level in Huaraz. For all three avalanche events, three-dimensional hydrodynamic models show large waves generated in the lake from the impact resulting in overtopping of the damming moraine. Despite very high discharge rates (up to 63.4 × 103 m3 s−1), the erosion from the overtopping wave did not result in failure of the damming moraine when simulated with a hydro-morphodynamic model using excessively conservative soil characteristics that provide very little erosion resistance. With the current lake level, all three avalanche events result in inundation in Huaraz due to wave overtopping, and the resulting preliminary hazard map shows a total affected area of 2.01 km2, most of which is in the high hazard category. Lowering the lake has the potential to reduce the affected area by up to 35 %, resulting in a smaller portion of the inundated area in the high hazard category.

Debris thickness plays an important role in regulating ablation rates on debris-covered glaciers as well as controlling the likely size and location of supraglacial lakes. Despite its importance, lack of knowledge about debris properties and associated energy fluxes prevents the robust inclusion of the effects of a debris layer into most glacier surface energy balance models. This study combines fieldwork with a debris-covered glacier energy balance model to estimate debris temperatures and ablation rates on Imja–Lhotse Shar Glacier located in the Everest region of Nepal. The debris properties that significantly influence the energy balance model are the thermal conductivity, albedo, and surface roughness. Fieldwork was conducted to measure thermal conductivity and a method was developed using Structure from Motion to estimate surface roughness. Debris temperatures measured during the 2014 melt season were used to calibrate and validate a debris-covered glacier energy balance model by optimizing the albedo, thermal conductivity, and surface roughness at 10 debris-covered sites. Furthermore, three methods for estimating the latent heat flux were investigated. Model calibration and validation found the three methods had similar performance; however, comparison of modeled and measured ablation rates revealed that assuming the latent heat flux is zero may overestimate ablation. Results also suggest that where debris moisture is unknown, measurements of the relative humidity or precipitation may be used to estimate wet debris periods, i.e., when the latent heat flux is non-zero. The effect of temporal resolution on the model was also assessed and results showed that both 6 h data and daily average data slightly underestimate debris temperatures and ablation rates; thus these should only be used to estimate rough ablation rates when no other data are available.

Glacial-dominated areas pose unique challenges to downstream communities in adapting to recent and continuing global climate change, including increased threats of glacial lake outburst floods (GLOFs) that can increase risk due to flooding of downstream communities and cause substantial impacts on regional social, environmental and economic systems. The Imja glacial lake (or Imja Tsho) in Nepal, which has the potential to generate a GLOF, was studied using a two-dimensional debris-flow inundation model in order to evaluate the effectiveness of proposed measures to reduce possible flooding impacts to downstream communities by lowering the lake level. The results indicate that only minor flood impact reduction is achieved in the downstream community of Dingboche with modest (~3 m) lake lowering. Lowering the lake by 10 m shows a significant reduction in inundated area. However, lowering the lake by 20 m almost eliminates all flood impact at Dingboche. Further downstream at Phakding, the impact of the GLOF is significant and similar reductions in inundation are likely as a result of lake lowering.

Original abstract: This paper studies the lake dynamics for avalanche-triggered glacial lake outburst floods (GLOFs) in the Cordillera Blanca mountain range in Ancash, Peru. As new glacial lakes emerge and existing lakes continue to grow, they pose an increasing threat of GLOFs that can be catastrophic to the communities living downstream. In this work, the dynamics of displacement waves produced from avalanches are studied through three-dimensional hydrodynamic simulations of Lake Palcacocha, Peru, with an emphasis on the sensitivity of the lake model to input parameters and boundary conditions. This type of avalanche-generated wave is an important link in the GLOF process chain because there is a high potential for overtopping and erosion of the lake-damming moraine. The lake model was evaluated for sensitivity to turbulence model and grid resolution, and the uncertainty due to these model parameters is significantly less than that due to avalanche boundary condition characteristics. Wave generation from avalanche impact was simulated using two different boundary condition methods. Representation of an avalanche as water flowing into the lake generally resulted in higher peak flows and overtopping volumes than simulating the avalanche impact as mass–momentum inflow at the lake boundary. Three different scenarios of avalanche size were simulated for the current lake conditions, and all resulted in significant overtopping of the lake-damming moraine. Although the lake model introduces significant uncertainty, the avalanche portion of the GLOF process chain is likely to be the greatest source of uncertainty. To aid in evaluation of hazard mitigation alternatives, two scenarios of lake lowering were investigated. While large avalanches produced significant overtopping waves for all lake-lowering scenarios, simulations suggest that it may be possible to contain waves generated from smaller avalanches if the surface of the lake is lowered. Artículo en acceso abierto Estudia la dinámica del lago Palcacocha respecto a las inundaciones por desborde violento de lago glaciar (en inglés, Glacier lake outburst flood o GLOF) ocurridos en la cordillera Blanca en Áncash, Perú. Manifiesta que el surgimiento de nuevos lagos glaciares y el crecimiento de los lagos existentes representan una amenaza cada vez mayor que GLOF y que pueden ser catastróficas para las comunidades que viven aguas abajo.

On 3 September 1998, a glacial lake outburst flood (GLOF) that originated from Tam Pokhari occurred in the Hinku valley of the eastern Nepal Himalaya. This study analyses the lake's geomorphic and hydrologic conditions prior to the outburst, and evaluates the conditions that could contribute to a future flood through photogrammetric techniques. We processed high-resolution Corona KH-4A (2.7 m) and ALOS PRISM (2.5 m) stereo-images taken before and after the GLOF event, and produced detailed topographic maps (2-m contour interval) and DEMs (5 m × 5 m). We (re-) constructed lake water surfaces before (4410 ± 5 m) and after (4356 ± 5 m) the outburst, and reliably estimated the lake water surface lowering (54 ± 5 m) and the water volume released (19.5 ± 2.2 × 106 m3) from the lake, showing good agreement with the results obtained from ground-based measurements. The most relevant conditions that may have influenced the catastrophic drainage of Tam Pokhari in 1998 include the presence of: (i) a narrow (75 ± 6 m), steep (up to 50°) and high (120 ± 5 m) moraine dam; (ii) high lake level (8 ± 5 m of freeboard) and (iii) a steep overhanging glacier (>40°). The lake outburst substantially altered the immediate area, creating a low and wide (>500 m) outwash plain below the lake, a wide lake outlet channel (~50 m) and a gentle channel slope (~3–5°). Our new data suggest that the likelihood of a future lake outburst is low. Our results demonstrate that the datasets produced by photogrammetric techniques provide an excellent representation of micro-landform features on moraine dams, lake water surfaces and the changes in both over time, thereby allowing highly accurate pre- and post-GLOF (volumetric) change analysis of glacial lakes. Furthermore, it enables precise measurement of several predictive variables of GLOFs that can be useful for identifying potentially dangerous glacial lakes or prioritizing them for detailed field investigations. Copyright © 2015 John Wiley & Sons, Ltd.

Glaciated mountains remain among the most under-studied regions in the world from a physical, social and climate change perspective, which complicates the development of appropriate adaptation and ...

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.

This paper studies the lake dynamics for avalanche-triggered glacial lake outburst floods (GLOFs) in the Cordillera Blanca mountain range in Ancash, Peru. As new glacial lakes emerge and existing lakes continue to grow, they pose an increasing risk of GLOFs that can be catastrophic to the communities living downstream. In this work, Lake Palcacocha is used as a case study to analyze the upper watershed processes that typically comprise a GLOF event, specifically the lake dynamics when an avalanche produces a large tsunami-like wave that might overtop and erode the lake-damming moraine. Dynamics of avalanche-generated impulse waves were investigated through three-dimensional hydrodynamic lake simulations of potential GLOF scenarios at Lake Palcacocha, Peru. Wave generation from avalanche impact was simulated using two different boundary condition methods. Representation of an avalanche as water flowing into the lake generally resulted in higher peak flows and overtopping volumes than simulating the avalanche impact as mass-momentum inflow at the lake boundary. Three different scenarios of avalanche size were simulated for the current lake conditions, and all resulted in significant overtopping of the lake-damming moraine. The lake model was evaluated for sensitivity to turbulence model and grid resolution, and the uncertainty due to these model parameters is significantly less than that due to avalanche boundary condition characteristics. Although the lake model introduces significant uncertainty, the avalanche portion of the GLOF process chain is the greatest source of uncertainty. To aid in evaluation of hazard mitigation alternatives, two scenarios of lake lowering were investigated. While large avalanches produced significant overtopping waves for all lake-lowering scenarios, simulations suggest that it may be possible to contain waves generated from smaller avalanches if the surface of the lake is lowered.

Imja Tsho, located in the Sagarmatha (Everest) National Park of Nepal, is one of the most studied and rapidly growing lakes in the Himalayan range. Compared with previous studies, the results of our sonar bathymetric survey conducted in September of 2012 suggest that its maximum depth has increased from 90.5 to 116.3 ± 5.2 m since 2002, and that its estimated volume has grown from 35.8 ± 0.7 to 61.7 ± 3.7 million m3. Most of the expansion of the lake in recent years has taken place in the glacier terminus–lake interface on the eastern end of the lake, with the glacier receding at about 52 m yr−1 and the lake expanding in area by 0.04 km2 yr−1. A ground penetrating radar survey of the Imja–Lhotse Shar glacier just behind the glacier terminus shows that the ice is over 200 m thick in the center of the glacier. The volume of water that could be released from the lake in the event of a breach in the damming moraine on the western end of the lake has increased to 34.1 ± 1.08 million m3 from the 21 million m3 estimated in 2002.

Debris thickness is an important characteristic of debris-covered glaciers in the Everest region of the Himalayas. The debris thickness controls the melt rates of the glaciers, which has large implications for hydrologic models, the glaciers' response to climate change, and the development of glacial lakes. Despite its importance, there is little knowledge of how the debris thickness varies over these glaciers. This paper uses an energy balance model in conjunction with Landsat7 Enhanced Thematic Mapper Plus (ETM+) satellite imagery to derive thermal resistances, which are the debris thickness divided by the thermal conductivity. Model results are reported in terms of debris thickness using an effective thermal conductivity derived from field data. The developed model accounts for the nonlinear temperature gradient in the debris cover to derive reasonable debris thicknesses. Fieldwork performed on Imja–Lhotse Shar Glacier in September 2013 was used to compare to the modeled debris thicknesses. Results indicate that accounting for the nonlinear temperature gradient is crucial. Furthermore, correcting the incoming shortwave radiation term for the effects of topography and resampling to the resolution of the thermal band's pixel is imperative to deriving reasonable debris thicknesses. Since the topographic correction is important, the model will improve with the quality of the digital elevation model (DEM). The main limitation of this work is the poor resolution (60 m) of the satellite's thermal band. The derived debris thicknesses are reasonable at this resolution, but trends related to slope and aspect are unable to be modeled on a finer scale. Nonetheless, the study finds this model derives reasonable debris thicknesses on this scale and was applied to other debris-covered glaciers in the Everest region.

In the Rio Grande transboundary basin, environmental flows have not been considered as an integral part of the water man- agement. This research focuses on the Big Bend, a reach located along the Rio Grande mainstem. Important natural regions of the Chihuahuan Desert are threatened due to the lack of environmental flows. In this paper is estimated the maximum volume of water available for environmental flows without affecting human and international water requirements, and without increasing the flood risk in Presidio-Ojinaga. Environmental flows are proposed based on an analysis of the prior reservoir alteration hydrology of the river. A planning model was built to simulate the water allocation system and evaluate alternative policies. A reservoir reoperation policy for Luis L. Leon reservoir is proposed to supply environmental flows without violating the system constraints. The policy that supplies the maximum water to the environment is two-thirds (66%) of the prior reservoir alteration conditions; it also improves human water supply, treaty obligations, and decreases flood risk. DOI: 10.1061/(ASCE)WR.1943-5452.0000331. © 2014 American Society of Civil Engineers. Author keywords: Environmental flows; Reservoir reoperation; Integrated water management; Adaptive management; Rio Grande.

A new method of participatory decision support that can be used in transboundary basins is presented. The framework of this method relies first on the creation of a transboundary geographic information system database to store hydrologic data and allow easy access to data from stakeholders. A participatory hydro-political framework is developed to help set up hydrologic models and evaluate joint water management scenarios. Results show that the countries of the Jordan River could benefit from the framework and in the case of southern Lebanon, six climate stations should be replaced or reactivated. Finally, the mechanism of a Lebanese Hydrologic Information System is presented and shows that an observation data model will facilitate science and policy integration.

Glacier outburst floods with origins from Lhotse Glacier, located in the Everest region of Nepal, have occurred during the transitional early monsoon season in each of the last two years. The most recent event was witnessed by the investigators on 12 June 2016. Observations regarding the magnitude of the 2016 outburst flood and a reconstruction of the flood path immediately following the event are presented. These observations highlight the lack of existing knowledge regarding these glacier hazards and provide valuable insight to help spur future investigations.

The Orontes River Basin is shared among Lebanon, Syria, and Turkey. These waters are a critical resource for the development of these co-riparians in terms of both water and national security. This article presents the results of a comprehensive institutional study of river basin agreement and conflicts in the Orontes Basin since the 1920s. This article identifies the strengths and weaknesses of the different bilateral agreements between Turkey, Syria and Lebanon and the power balance relation between the co-riparians especially under the current political events.

This article analyzes the water security risks in the Orontes basin shared between Syria, Lebanon and Turkey. A complete description of the watershed's hydrography and hydrology is presented, and then, using a geographic database, an optimization method is used based on the nine factors of the UN Convention to allocate water equitably between the co-riparians. The optimization results show that Turkey and Lebanon could benefit from additional water if new negotiations are initiated. We conclude that the role of Geographic Information System (GIS) in transboundary basins is essential once a multilateral agreement occurs, whereby GIS will assist in data sharing and standardization to evaluate future policy alternatives.

This article describes the collaborative modeling process and the resulting water resources planning model developed to evaluate water management scenarios in the transboundary Rio Grande basin. The Rio Grande is a severely water stressed basin that faces numerous management challenges as it crosses numerous jurisdictional boundaries. A collaborative process was undertaken to identify and model water management scenarios to improve water supply for stakeholders, the environment, and international obligations of water delivery from Mexico to the United States. A transparent and open process of data collection, model building, and scenario development was completed by a project steering committee composed of university, nongovernmental, and governmental experts from both countries. The outcome of the process was a planning model described in this article, with data and operations that were agreed on by water planning officials in each country. Water management scenarios were created from stakeholder input and were modeled and evaluated for effectiveness with the planning model.

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.

This paper focuses on calibration and validation of a hydrologic model of the Rio Conchos Basin, a main Mexican tributary of the binational Rio Grande Basin. The Rio Conchos provides approximately 55% of the water deliveries to the United States under the 1944 water treaty signed between both countries. The hydrologic modeling has been developed using the one-dimensional, two-layer soil moisture accounting scheme embedded in the Water Evaluation and Planning (WEAP) model. A 10-year period was used to calibrate the model, which was achieved by a trial-and-error method for the adjustment of the model parameters. The results show a Nash-Sutcliffe coefficient of 0.84 at Ojinaga station (mouth of the basin) and 0.81 at La Boquilla, indicating good model performance. In general the model predicts well the monthly, annual, and maximum flows; but there are significant differences between the model values and undeveloped (naturalized) flows for low flow periods, especially at La Boquilla station. For model...

The Jordan River Basin is under great hydric stress. Increases in population and agricultural demand are contributing to the closure of the basin. This paper analyses the results of integrated water resources planning model (WEAP) by studying the vulnerability of water resources in the lower Jordan River under a changing climate pattern and growing water demands. Water balance models show that all aquifers supplying the city of Amman will be depleted within the next few decades. Mitigation measures should include the introduction of additional water into the basin through the Red Sea–Dead Sea canal, in addition to demand management measures such as water conservation and increase in irrigation efficiency. The findings of this study would provide a useful guide to the co-riparians for policy formulation, decision making and dispute resolution. Cooperation among the five riparian countries may be improved by building a Geographic Information System (GIS) database that provides access to accurate data for hydrological analysis.

Glacial lake outburst floods (GLOFs) pose a significant threat to downstream communities and infrastructure due to their potential to rapidly unleash stored lake water. The most common triggers of these GLOFs are mass movement entering the lake and/or the self-destruction of the terminal moraine due to hydrostatic pressures or a buried ice core. This study initially uses previous qualitative and quantitative assessments to understand the hazards associated with eight glacial lakes in the Nepal Himalaya that are widely considered to be highly dangerous. The previous assessments yield conflicting classifications with respect to each glacial lake, which spurred the development of a new holistic, reproducible, and objective approach based solely on remotely sensed data. This remote hazard assessment analyzes mass movement entering the lake, the stability of the moraine, and lake growth in conjunction with a geometric GLOF to determine the downstream impacts such that the present and future risk associated with each glacial lake may be quantified. The new approach is developed within a hazard, risk, and management action framework with the aim that this remote assessment may guide future field campaigns, modeling efforts, and ultimately risk-mitigation strategies. The remote assessment was found to provide valuable information regarding the hazards faced by each glacial lake and results were discussed within the context of the current state of knowledge to help guide future efforts.

The Jordan River Basin is shared between Lebanon, Syria, Israel, Jordan and Palestine; the waters of the River are a critical resource for the future water security of the co-riparians. Because of the political situation in the region, field data such as rainfall and evapotranspiration are very difficult to obtain making the use of remote sensing and Geographic Information System (GIS) very useful to study water availability in the basin. The approach used in this paper integrates recently compiled data derived from satellite imagery (evapotranspiration, rainfall, and digital elevation model) into a GIS geodatabase to measure the contribution of each riparian country to the total available water in the basin.

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 water planning and management policies of the Rio Grande basin no longer respond to the sustainable needs of water users, environment, and international commitments of this transboundary basin between Mexico and the United States. This paper describes how groundwater banking through an in lieu method is one approach leading to better water management in this basin. In lieu groundwater banking is a conjunctive water allocation policy applicable to water users supplied from surface water and groundwater sources. A basin simulation model of the Rio Grande basin, built in the water evaluation and planning system (WEAP) software, was used to evaluate the groundwater banking policy. Two scenarios are discussed: a baseline scenario without new water allocation policies implemented and a groundwater banking scenario considering the in lieu groundwater banking method implemented in the Meoqui aquifer. Results show that groundwater banking can significantly improve water management in the basin, increasing syst...

In this paper we offer a negotiation and cooperative game theory application to international water in the classroom. A simulation game was developed for the Aral Sea water dispute as part of a textbook prepared for teaching a diverse group of students a graduate-level International Water course. A condensed version of the Aral Sea Basin water dispute and hydrology was prepared. The game allows students to realize the complexity of hydrology and geography, the linkage between hydrology and conflict and cooperation, and the impact of external factors, such as climate change, on the extent of the conflict and its likely resolution. The game was used to simulate negotiations between a subset of the basin riparians, demonstrating the value of information in negotiation. Various cooperative game theory concepts were demonstrated and applied by students through a set of assignments representing a variety of likely states of nature and various development interventions.

The development of relational databases from which simulation models can access data needed to describe the systems being modeled is fundamental to integrated river basin management, especially in shared, transboundary basins. Creating a geographically referenced database, a geodatabase, for the Rio Grande/Rio Bravo Basin represents the first major attempt to establish a more complete understanding of the basin as a whole, using both Mexican and United States geospatial and temporal water resources data. From the geodatabase, it is possible to obtain information about climatology, water availability, water uses, hydraulic infrastructure, and watershed properties in the basin. These data can be used in simulation models to calculate the state of basin water availability under different climatic and development scenarios and management plans in the future. This geodatabase is intended to be a tool to assist in sharing data to enhance binational cooperation between Mexico and the United States concerning water in this basin, providing accurate and reliable data necessary for analysis and resolution of water resources issues.

A multistage stochastic optimization model using linear programming was developed to provide planning tools for Lower Colorado River Authority in the operation of the Highland Lakes system, as well as a framework for examining the operation of four irrigation districts. Three primary objectives were maximized in the model: (1) Revenues from rice production, (2) recreation benefits associated with lake use, and (3) revenues from hydropower generation. The model includes stochastic inflows, weather-dependent irrigation demands, an interruptible contract decision function, a reservoir space rule to balance storage volumes between reservoirs, hydropower production, municipal and irrigation return flows, and bay and estuary inflow requirements. Model weights and coefficients were calibrated to reflect actual market prices and economic constraints, or to represent water management priorities. Stochastic optimization is used to account for meteorological uncertainty using representative inflow scenarios. Considering the uncertainty in the inflows, the model predicts optimum acreage levels, reservoir storage levels, reservoir releases, and other decisions, to maximize total expected benefits in the system.

In the semi-arid Amudarya delta region (Aral Sea Basin) the human-controlled hydrological regime is a major factor influencing ecosystem dynamics. Alterations to the flow of the Amudarya River, mainly to serve the needs of irrigated agriculture during Soviet times, have caused severe environmental degradation. Since independence, the former Soviet Union states of the basin are searching for new, ecologically sound, water management strategies to mitigate the damages to economy, human populations and ecosystems. To assist in the evaluation of tradeoffs in water allocation and the determination of restoration goals, we created a simple water management model for the Amudarya River and its delta region with the modeling system EPIC (originally developed by the USAID project ‘Environmental Policies and Institutions for Central Asia’). The water management model determines optimal water allocation in the irrigation network by multi-objective optimization in monthly time steps. Water management alternatives can be developed for a time period of up to 15 years based on changing requirements of the water users (e.g. as a result of increased water use efficiency in agriculture), inflow to the delta (e.g. increase in water use upstream), priorities of the optimization criteria (e.g. reflecting policy decisions) or introducing minimum flow requirements to selected canals. Historic salt dynamics of the Tyuyamuyun reservoir system at the entrance to the Amudarya delta were investigated and EPIC was extended to treat such multi-body reservoir systems. The model was calibrated and tested using a high water (1994) and a low water (1997) year. Modeled water allocation takes place in accordance with observational data. The model reacts well to changes in allocation priorities given by the user. Application of the model to a 14-year characteristic time period was successful. The model constitutes a main module of an integrated GIS-based simulation tool that facilitates the evaluation of the ecological effects of alternative water management strategies in the Northern Amudarya delta.

Sustainable irrigation water management should simultaneously achieve two objectives: sustaining irrigated agriculture for food security and preserving the associated natural environment. A stable relationship should be maintained between these two objectives now and in the future, while potential conflicts between these objectives should be mitigated through appropriate irrigation practices. The Aral Sea region in Central Asia is such a region that is most famous for its conflict between sustaining irrigated agriculture and preserving the environment. The current status of irrigation water management in the Aral Sea region demonstrates the Aral Sea disaster as a prime example for unsustainable irrigation development. This paper presents an integrated modeling framework for sustainable irrigation management analysis and applies it to analyze irrigation water management in the Aral Sea region. Based on the modeling outputs, alternative futures of the irrigation practice in the region are explored and it is found that to maintain current irrigation practices will lead to worsening environmental and economic consequences. Investments in infrastructure improvements (about annualized US $299 million) and crop pattern change will be necessary to sustain the irrigated agriculture and the associated environment in the region. Moreover, a penalty tax on salt discharge less than 50 US$ per ton as an economic incentive may help address environmental problems, while having only a small effect on irrigation profit.

The interdisciplinary nature of water resources problems requires the integration of technical, economic, environmental, social, and legal aspects into a coherent analytical framework. This paper presents the development of a new integrated hydrologic-agronomic-economic model in the context of a river basin in which irrigation is the dominant water use and irrigation-induced salinity presents a major environmental problem. The model’s main advantage is its ability to reflect the interrelationships between essential hydrologic, agronomic, and economic components and to explore both economic and environmental consequences of various policy choices. All model components are incorporated into a single consistent model, which is solved in its entirety by a simple but effective decomposition approach. The model is applied to a case study of water management in the Syr Darya River basin in Central Asia.

Since independence, joint use of water resources in the Aral Sea basin has been a critical international problem between the Central Asian republics, especially in the Syr Darya basin where the tradeoffs between use of water for agricultural and energy production are very acute. Previous centralized methods of planning, formation of independent countries, and the emergence of national interests have made the coordinated operation of the Naryn-Syr Darya Cascade of reservoirs complicated. In order to implement recent international agreements on the use of water and energy resources of the Syr Darya basin and provide the upstream-downstream exchanges of electric fuel and energy resources required by the agreements, a model was developed to optimize operation modes for the major reservoirs of the basin. This model was used as the basis for developing a complex model of the operation of the Naryn Cascade of hydropower plants and the interactions of the Kyrgyz Republic energy system and the other Syr D...

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 km ²and 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.

Moraine dam collapse is one of the causes of glacial lake outburst floods. Available models seek to predict both moraine breach formation and lake outflow. The models depend on hydraulic, erosion, and geotechnical parameters that are mostly unknown or uncertain. This paper estimates the outflow hydrograph caused by a potential erosive collapse of the moraine dam of Lake Palcacocha in Peru and quantifies the uncertainty of the results. The overall aim is to provide a simple yet hydraulically robust approach for calculating the expected outflow hydrographs that is useful for risk assessment studies. To estimate the peak outflow and failure time of the hydrograph, we assessed several available empirical equations based on lake and moraine geometries; each equation has defined confidence intervals for peak flow predictions. Complete outflow hydrographs for each peak flow condition were modeled using a hydraulic simulation model calibrated to match the peak flows estimated with the empirical equations. Failure time and peak flow differences between the simulations, and the corresponding empirical equations were used as error parameters. Along with an expected hydrograph, lower and upper bound hydrographs were calculated for Lake Palcacocha, representing the confidence interval of the results. The approach has several advantages: first, it is simple and robust. Second, it evaluates the capability of empirical equations to reproduce the conditions of the lake and moraine dam. Third, this approach accounts for uncertainty in the hydrographs estimations, which makes it appropriate for risk management studies.

A new method of participatory decision support that can be used in transboundary basins is presented. The framework of this method relies first on the creation of a transboundary geographic information system database to store hydrologic data and allow easy access to data from stakeholders. Results show that the countries of the Jordan River could benefit from the framework and in the case of southern Lebanon, six climate stations should be replaced or reactivated. Finally, the mechanism of a Lebanese Hydrologic Information System is presented and shows that an observation data model will facilitate science and policy integration. Introduction. The Jordan River Basin is shared between Jordan, Israel, Lebanon, Palestine (West Bank) and Syria. In the Middle East and North Africa (MENA) region, especially in the countries of the Jordan River Basin, data are insufficient or do not exist. Data are often not published in the Middle East for security reasons, e.g., Israel does not publish data on discharge (Klein 1998). Variability of data reporting is another problem. Several authors (Gunkel and Lange 2011; Mithen and Black 2011) mention that the lack of adequate data hinders model performance, and uncertainties increase due to the absence of calibration and validation of hydrological models (Gunkel and Lange 2011). Mithen and Black (2011) developed several rainfall run-off models for the Jordan River Basin and described the extreme difficulty of modeling in a data poor region. For transboundary settings, participatory methods have been successful in Europe under the Water Framework Directive (WFD) for interdisciplinary investigations based on an integrated approach (Molina 2011). Participatory integrated assessment (PIA) as defined by Parker et al. (2002) was found to be very helpful for managers in the restoration of extreme aquifer overexploitation in Spain (Molina 2011). A comprehensive review of the application of GIS and remote sensing to groundwater hydrology was also described by Jha et al. (2007). They showed that GIS and remote sensing studies are recommended to be carried out in conjunction with field investigations.

Debris thickness is an important characteristic of many debris-covered glaciers in the Everest region of the Himalayas. The debris thickness controls the melt rates of the glaciers, which has large implications for hydrologic models, the glaciers response to climate change, and the development of glacial lakes. Despite its importance, there is little knowledge of how the debris thickness varies over these glaciers. This paper uses an energy balance model in conjunction with Landsat7 ETM+ satellite imagery to derive thermal resistances, which is the debris thickness divided by the thermal conductivity. The developed model accounts for the nonlinear temperature gradient in the debris cover to derive accurate thermal resistances. Fieldwork performed on Lhotse Shar/Imja glacier in September 2013 was used to validate the satellite-derived thermal resistances. Results indicate that accounting for the nonlinear temperature gradient is crucial. Furthermore, correcting the incoming shortwave radiation term for the effects of topography and including the turbulent heat fluxes is imperative to derive accurate thermal resistances. Since the topographic correction is important, the model will improve with the quality of the DEM. The main limitation of this work is the poor resolution (60 m) of the satellite's thermal band. The derived thermal resistances are accurate at this resolution, but are unable to derive trends related to slope and aspect on a finer scale. Nonetheless, the study finds this model derives accurate thermal resistances on this scale and is transferable to other debris-covered glaciers in the Everest region.

Most large nonlinear optimization models are composed of “pieces”—subsets of decision variables—and constraints whose union is the entire model. Each piece represents an additional aspect of the situation being modeled. This opens the possibility of solving the simplest piece first, adding the constraints and variables of another piece, and solving this submodel from a starting point provided by the first solution. This process is repeated until the original model is solved. This “piece-by-piece” approach provides each submodel with a good starting point, which greatly increases the probability that a good nonlinear solver will find an optimal solution. We apply it to a large multiperiod nonlinear programming (NLP) model with 13,700 variables, 10,000 equations, and a high degree of nonlinearity (54.3% of the nonzero Jacobian elements are nonconstant), arising from water resources planning and operation in a river basin. Using the GAMS modeling language and the CONOPT2 NLP solver, the piece-by-piece method...

Gradient-based nonlinear programming (NLP) methods can solve problems with smooth nonlinear objectives and constraints. However, in large and highly nonlinear models, these algorithms can fail to find feasible solutions, or converge to local solutions which are not global. Evolutionary search procedures in general, and genetic algorithms (GAs) specifically, are less susceptible to the presence of local solutions. However, they often exhibit slow convergence, especially when there are many variables, and have problems finding feasible solutions in constrained problems with “narrow” feasible regions. In this paper, we describe strategies for solving large nonlinear water resources models management, which combine GAs with linear programming. The key idea is to identify a set of complicating variables in the model which, when fixed, render the problem linear in the remaining variables. The complicating variables are then varied by a GA. This GA&LP approach is applied to two nonlinear models: a reservoir operation model with nonlinear hydropower generation equations and nonlinear reservoir topologic equations, and a long-term dynamic river basin planning model with a large number of nonlinear relationships. For smaller instances of the reservoir model, the CONOPT2 nonlinear solver is more accurate and faster, but for larger instances, the GA&LP approach finds solutions with significantly better objective values. The multiperiod river basin model is much too large to be solved in its entirety. The complicating variables are chosen here so that, when they are fixed, each period's model is linear, and these models can be solved sequentially. This approach allows sufficient model detail to be retained so that long-term sustainability issues can be explored.

Nonconvex nonlinear programming (NLP) problems arise frequently in water resources management, e.g., reservoir operations, groundwater remediation, and integrated water quantity and quality management. Such problems are usually large and sparse. Existing software for global optimization cannot cope with problems of this size, while current local sparse NLP solvers, e.g., MINOS (Murtagh and Saunders 1987), or CONOPT (Drud 1994) cannot guarantee a global solution. In this paper, we apply the Generalized Benders Decomposition (GBD) algorithm to two large nonconvex water resources models involving reservoir operations and water allocation in a river basin, using an approximation to the GBD cuts proposed by Floudas et al. (1989) and Floudas (1995). To ensure feasibility of the GBD subproblem, we relax its constraints by introducing elastic slack variables, penalizing these slacks in the objective function. This approach leads to solutions with excellent objective values in run times much less than the GAMS NLP solvers MINOS5 and CONOPT2, if the complicating variables are carefully selected. Using these solutions as initial points for MINOS5 or CONOPT2 often leads to further improvements.