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This study characterizes the hydrological regime of the Upper Ayeyarwaddy River Basin (UARB) of Myanmar under current and future climate change scenarios by using the Soil and Water Assessment Tool (SWAT). The model simulation results show that the annual precipitation, actual evapotranspiration and water yields are 1,578, 524 and 1,010 mm, respectively. These will increase by 13–28%, 11–24% and 42–198% under two representative concentration pathways (RCPs), RCP 4.5 and RCP 8.5, for the future. There is seasonal variability across the cool, hot and rainy seasons in the agro-ecological regions – mountains, hills and inland plains. As in other Asian regions, the model shows that the wet (rainy) season is becoming wetter and the dry (cool) season is becoming drier in the UARB too.

Most existing climate impact assessments in Nepal only consider a limited number of generic climate indices such as means. Few studies have explored climate extremes and their sectoral implications, which in turn are key for informing policy and practice. This study evaluates future scenarios of extreme climate indices from the list of the Expert Team on Sector-specific Climate Indices (ET-SCI) and their sectoral implications in the Karnali Basin in western Nepal. First, future projections of 26 climate indices relevant to six climate-sensitive sectors in Karnali are made for the near (2021–2045), mid (2046–2070), and far (2071–2095) future for low- and high-emission scenarios (RCP4.5 and RCP8.5, respectively) using bias-corrected ensembles of 19 regional climate models from the COordinated Regional Downscaling EXperiment for South Asia (CORDEX-SA). Second, a qualitative analysis based on expert interviews and a literature review on the impact of the projected climate extremes on the climate-sensitive sectors is undertaken. We also used widely available global data sets such as DesInventar and national census data and disaster-specific mixed-effects regression models to assess the impact of precipitation extremes on landslide and flood mortality. Both the temperature and precipitation patterns are projected to deviate significantly from the historical reference already from the near future with increased occurrences of extreme events. Results show winter in the highlands is expected to become warmer and dryer. The hot and wet tropical summer in the lowlands will become hotter with longer warm spells and fewer cold days. Low-intensity precipitation events will decline, but the magnitude and frequency of extreme precipitation events will increase. Furthermore, an increase in one standardized unit in maximum one-day precipitation increases flood mortality by 33%, and heavy rain days increase landslide mortality by 45%.

Climatic disaster impacts, such as loss of human life as its most severe consequence, have been rising globally. Several studies argue that the growth in exposure, such as population, is responsible for the rise and the role of climate change is not evident. While disaster mortality is highest in low-income countries, existing studies focus mostly on developed countries. Here we address this impact attribution question in the context of the Global South using disaster-specific mixed-effects regression models. We show that the rise in landslide and flood mortality in a low-income country Nepal between 1992-2021 is attributable primarily to the increased precipitation extremes. An increase in one standardized unit in maximum one-day precipitation increases flood mortality by 33%, and heavy rain days increase landslide mortality by 45%. A one-unit increase in per capita income decreases landslide and flood mortality by 30% and 45%, respectively. Population density does not show significant effects.

Climatic disaster impacts, such as loss of human life as its most severe consequence, have been rising globally. Several studies argue that population growth is responsible for the rise, and the role of climate change is not evident. While disaster mortality is highest in low-income countries, existing studies focus mostly on developed countries. Here we address this impact attribution question in the context of the Global South using disaster-specific mixed-effects regression models. We show that the rise in landslide and flood mortality in a low-income country such as Nepal between 1992-2021 is primarily attributable to increased precipitation extremes. An increase in one standardized unit in maximum one-day precipitation increases flood mortality by 33%, and heavy rain days increase landslide mortality by 45%. Similarly, a one-unit increase in per capita income decreases landslide and flood mortality by 30% and 45%, respectively. Population density does not show significant effects.

The impacts of climatic disasters have been rising globally. Several studies argue that this upward trend is due to rapid growth in the population and wealth exposed to disasters. Others argue that rising extreme weather events due to anthropogenic climate change are responsible for the increase. Hence, the causes of the increase in disaster impacts remain elusive. Disaster impacts relative to income are higher in low-income countries, but existing studies are mostly from developed countries or at the cross-country level. Here we assess the spatiotemporal trends of climatic disaster impacts and vulnerability and their attribution to climatic and socioeconomic factors at the subnational scale in a low-income country, using Nepal as a case study. Loss of life is the most extreme consequence of disasters. Therefore, we employed human mortality as a measure of disaster impacts, and mortality normalized by exposed population as a measure of human vulnerability. We found that climatic disaster frequency and mortality increased in Nepal from 1992 to 2021. However, vulnerability decreased, most likely due to economic growth and progress in disaster risk reduction and climate change adaptation. Disaster mortality is positively correlated with disaster frequency and negatively correlated with per capita income but is not correlated with the exposed population. Hence, population growth may not have caused the rise in disaster mortality in Nepal. The strong rise in disaster incidence, potentially due to climate change, has overcome the effect of decreasing vulnerability and caused the rise in disaster mortality.

Human mortality and economic losses due to climatic disasters have been rising globally. Several studies argue that this upward trend is due to rapid growth in the population and wealth exposed to disasters. Others argue that rising extreme weather events due to anthropogenic climate change are responsible for the increase. Hence, the causes of the increase in disaster impacts remain elusive. Disaster impacts are higher in low-income countries, but existing studies are mostly from developed countries or at the cross-country level. This study will assess the attribution of rising climatic disaster mortality to indicators of climatic hazards, exposure, and vulnerability at the subnational scale in a low-income country, using Nepal as a case study. This empirical study at the scale of 753 local administrative units of Nepal will follow a regression-based approach that will overcome the limitations of the commonly used loss normalization approach in studying the attribution of disaster-induced loss and damage.In Nepal, landslides and floods account for more than two-thirds of the total climatic disaster mortality. Hence, we will use the past 30 years (1991-2020) landslides and floods mortality data from DesInventar and Nepal's Disaster Risk Reduction portal as the dependent variable. As explanatory variables to represent climatic hazards, we will estimate and use mean and extreme precipitation indices from observational data by the Department of Hydrology and Meteorology Nepal. We will use the local unit’s population as a proxy of disaster exposure. Socio-economic and environmental indicators such as annual per capita income, percentage of people with access to mobile phones and internet, land cover distribution, and slope will be used as indicators of vulnerability. Exposure and vulnerability indicators data will be accessed from Nepal’s Central Bureau of Statistics and other sources. This study is expected to identify indicators of climatic hazards, exposure, and vulnerability that could explain the spatial and temporal variability of climatic disaster mortality in Nepal. Similarly, it will provide new insights on the role of climate change on rising climatic disaster mortality from the low-income countries’ context.

The impacts of climatic disasters have been rising globally. Several studies argue that this upward trend is due to rapid growth in the population and wealth exposed to disasters. Others argue that rising extreme weather events due to anthropogenic climate change are responsible for the increase. Hence, the causes of the increase in disaster impacts remain elusive. Disaster impacts are higher in low-income countries, but existing studies are mostly from developed countries or at the cross-country level. Here we assess the spatiotemporal trends of climatic disaster impacts and vulnerability and their attribution to climatic and socioeconomic factors at the subnational scale in a low-income country, using Nepal as a case study. Loss of life is the most extreme consequence of disasters. Therefore, we employed human mortality as a measure of disaster impacts, and mortality normalized by exposed population as a measure of human vulnerability. We found that climatic disaster frequency and mortality increased in Nepal from 1991 to 2020. However, vulnerability decreased, most likely due to economic growth and progress in disaster risk reduction and climate change adaptation. Disaster mortality is positively correlated with disaster frequency and negatively correlated with per capita income but is not correlated with exposed population. Hence, population growth may not have caused the rise in disaster mortality in Nepal. The strong rise in disaster incidence, potentially due to climate change, has overcome the effect of decreasing vulnerability and caused the rise in disaster mortality.

Existing climate projections and impact assessments in Nepal only consider a limited number of generic climate indices such as means. Few studies have explored climate extremes and their sectoral implications. This study evaluates future scenarios of extreme climate indices from the list of the Expert Team on Sector-specific Climate Indices (ET-SCI) and their sectoral implications in the Karnali Basin in western Nepal. First, future projections of 26 climate indices relevant to six climate-sensitive sectors in Karnali are made for the near (2021–2045), mid (2046–2070), and far (2071–2095) future for low- and high-emission scenarios (RCP4.5 and RCP8.5, respectively) using bias-corrected ensembles of 19 regional climate models from the COordinated Regional Downscaling EXperiment for South Asia (CORDEX-SA). Second, a qualitative analysis based on expert interviews and a literature review on the impact of the projected climate extremes on the climate-sensitive sectors is undertaken. Both the temperature and precipitation patterns are projected to deviate significantly from the historical reference already from the near future with increased occurrences of extreme events. Winter in the highlands is expected to become warmer and dryer. The hot and wet tropical summer in the lowlands will become hotter with longer warm spells and fewer cold days. Low-intensity precipitation events will decline, but the magnitude and frequency of extreme precipitation events will increase. The compounding effects of the increase in extreme temperature and precipitation events will have largely negative implications for the six climate-sensitive sectors considered here.

Water resources can play significant roles in development pathways for water-endowed, low-income countries like Nepal. This article describes three visions for water resource development in...

Chamelia (catchment area = 1603 km2), a tributary of Mahakali, is a snow-fed watershed in Western Nepal. The watershed has 14 hydropower projects at various stages of development. This study simulated the current and future hydrological system of Chamelia using the Soil and Water Assessment Tool (SWAT). The model was calibrated for 2001–2007; validated for 2008–2013; and then applied to assess streamflow response to projected future climate scenarios. Multi-site calibration ensures that the model is capable of reproducing hydrological heterogeneity within the watershed. Current water balance above the Q120 hydrological station in the forms of precipitation, actual evapotranspiration (AET), and net water yield are 2469 mm, 381 mm and 1946 mm, respectively. Outputs of five Regional Climate Models (RCMs) under two representative concentration pathways (RCPs) for three future periods were considered for assessing climate change impacts. An ensemble of bias-corrected RCM projections showed that maximum temperature under RCP4.5 (RCP8.5) scenario for near-, mid-, and far-futures is projected to increase from the baseline by 0.9 °C (1.1 °C), 1.4 °C (2.1 °C), and 1.6 °C (3.4 °C), respectively. Minimum temperature for the same scenarios and future periods are projected to increase by 0.9 °C (1.2 °C), 1.6 °C (2.5 °C), and 2.0 °C (3.9 °C), respectively. Average annual precipitation under RCP4.5 (RCP8.5) scenario for near-, mid-, and far-futures are projected to increase by 10% (11%), 10% (15%), and 13% (15%), respectively. Based on the five RCMs considered, there is a high consensus for increase in temperature but higher uncertainty with respect to precipitations. Under these projected changes, average annual streamflow was simulated to increase gradually from the near to far future under both RCPs; for instance, by 8.2% in near-, 12.2% in mid-, and 15.0% in far-future under RCP4.5 scenarios. The results are useful for planning water infrastructure projects, in Chamelia and throughout the Mahakali basin, to ensure long-term sustainability under climate change.

This chapter highlights the key dependences, linkages and challenges of water resources management. (Many of these issues discussed are revisited and illustrated in the following chapters.) The first part introduces surface and groundwater management in the terrestrial part of the water cycle. Comprehensive presentations of key hydrological phenomena and processes, monitoring, assessment and control are followed by overviews of dependences, linkages and challenges. The manifold facets of intensive human/resource interaction and inherent threats to the resources base are exposed. Both sections present examples illustrating differing contexts and options for solution. The second part summarizes the main drivers and challenges of contemporary water resources management and governance. It provides a critical overview of different water discourses in recent decades. The role of benchmark and recurring water events, their declarations and intergovernmental resolutions are analyzed, and the key concepts and methods of implementation are discussed.

Interventions to increase benefits from energy-food-water-environment systems can involve changing infrastructure configurations and/or operational rules. In a context of complexity due to interdependencies and uncertainty, resource system intervention appraisal should consider multiple facets of system performance and a variety of plausible future conditions to achieve robust systems that balance multiple stakeholder definitions of acceptable performance. This paper proposes a novel multi-method decision-making under deep uncertainty approach to hydropower system design. The most efficient and robust designs are identified; those that maximize benefits and balance stakeholder interests despite uncertainty. It is applicable in any context where efficient and robust future hydropower systems are sought. The proposed approach is demonstrated in Nepal, showing the robustness benefits of diversified infrastructure systems; here the mixed development of both storage and run-of-river dams. Stress testing of a selected efficient and robust hydropower investment bundle reveals that institutional or financial uncertainties can most threaten the viability of assets, even when significant climate change is anticipated.

The term "environmental flows" refers to a combination of features, including quantity, quality, and timing of water flows required to sustainably maintain a river's health, balancing both ecological and societal needs. Incorporating basic human livelihood and sociocultural aspects in environmental flow assessments alongside ecological concerns provides a more holistic perspective on water flow management. Here, we provide an assessment that complements an ecosystem functioning lens by focusing solely on quantifying the flows associated with livelihood activities and spiritual water requirements of local riparian communities in the Karnali basin in Western Nepal. This assessment is based on the first social survey related to environmental flows conducted in the Karnali basin. We collected data using mixed methods, including social surveys, key informant interviews, and focus group discussions, across six locations in the Karnali basin that provide us with a rich and dynamic perspective on the relationship between rivers and their surrounding communities, and the challenges faced by those communities. Among the subsistence and spiritual requirements of local communities are uses for activities that include drinking, small-scale irrigation, domestic needs, fishing, and ceremonial usage. All communities we visited most strongly associated the following activities with water flow variation: small-scale irrigation, fishing, ceremonial usage, domestic needs, and tourism. The water flows required for these key activities were quantified, and results from the six sites are presented in the form of a qualitative scale of minimum water levels (ranging across poor, acceptable, and ideal) required to meet vital local needs. The minimum acceptable water flow requirement to satisfy social criteria is just > 20% of the mean annual runoff at the visited locations. These requirements are particularly vital to consider, given ongoing efforts to tap the vast hydropower potential in Nepal through construction of major storage projects. Such projects would change the flow regime of affected rivers and potentially raise concerns that existing demands might be compromised.

Since the late 1990s, river basin planning has become a central idea in water resources management and a mainstream approach supported by international donors through their water programs globally. This article presents river basin planning as a function of power and contested arena of power struggles, where state actors create, sustain, and reproduce their bureaucratic power through the overall shaping of (imagined) bureaucratic territory. It argues that river basin planning is not an antidote to current ‘dysfunction’ in water resources management, rooted in overlapping jurisdictions, fragmented decision making, and bureaucratic competitions between various government agencies. On the contrary, it illustrates how river basin planning becomes a new ‘territorial frontier’, created and depicted by different government agencies as their envisioned operational boundary and as a means to sustain and increase their bureaucratic power and sectoral decision-making authority, amidst ongoing processes of federalism in Nepal.

The purpose of this study was to compare knowledge and practice of family planning methods among Chepang and Brahmin/ Chhetri men. Chepang are more disadvantage ethnicity of Nepal therefore by examine the knowledge and practice of family planning in these two groups it will be helpful to find out whether or not family planning program has been reach to un-reach group. Data were collected from the 1st Jestha 2070 to 31 Jestha 2070 (15.5.2013 to 14.6.2013) through interview methods. The average age group of both the respondents was between 26-35yrs. Majority of respondents had knowledge about both temporary and permanent (56.8 percent Chepang and 50.9 percent Brahmin/Chhetri). While most of the family planning information was obtained through a health worker (88.2 percent Chepang and 79.4 percent Brahmin/Chhetri). Family planning using was 42.1 percent in Chepang and 40.2 percent in Brahmin/Chhetri. Temporary family planning method was found to be commonly used (74.4 percent Chepang and 73.1 percent Brahmin/Chhetri). Spousal communication seemed to exist by two third portions in both the groups and the most common topic for discussion was about family and family size.

The Himalayas are highly susceptible to the impacts of climate change, as it consequently increases the vulnerability of downstream communities, livelihoods and ecosystems. Western Nepal currently holds significant potential as multiple opportunities for water development within the country are underway. However, it is also identified as one of the most vulnerable regions to climate change, with both an increase in the occurrence of natural disasters and exacerbated severity and impacts levels. Regional climate model (RCM) projections indicate warmer weather with higher variability in rainfall for this region. This paper combines bio-physical and social approaches to further study and understand the current climate shocks and responses present in Western Nepal. Data was collected from 3660 households across 122 primary sampling units across the Karnali, Mahakali and Mohana River basins along with focus group discussions, which provided a rich understanding of the currently perceived climatic shocks and related events. Further analysis of climatology was carried out through nine indices of precipitation and temperature that were found to be relevant to the discussed climate shocks. Results show that 79% of households reported experiencing at least one type of climate shock in the five-year period and the most common occurrence was droughts, which is also supported by the climate data. Disaggregated results show that perception varies with the region and among the basins. Analysis of climatic trends further show that irregular weather is most common in the hill region, although average reported frequency of irregular weather is higher in the mountain. Further analysis into the severity and response to climatic shocks suggest an imminent need for better adaptation strategies. This study&rsquo, s results show that a vast majority of respondents lack proper access to knowledge and that successful adaptation strategies must be adapted to specific regions to meet communities&rsquo, local needs.

Commonly described as the “water tower for Asia,” the Hindu Kush Himalaya (HKH) plays an important role in ensuring water, food, energy, and environmental security for much of the continent. The HKH is the source of ten major rivers that provide water—while also supporting food and energy production and a range of other ecosystem services—for two billion people across Asia. This chapter takes stock of current scientific knowledge on the availability of water resources in the HKH; the varied components of its water supply; the impact of climate change on future water availability; the components of water demand; and the policy, institutions, and governance challenges for water security in the region.

The Koshi Basin, spread across China, Nepal and India, is perceived as having high potential for hydropower and irrigation development, both seen as ways to promote economic development in the region. This paper quantifies and assesses the past and projected future spatial and temporal water balances in the Koshi Basin. Results show that precipitation and net water yield are lowest in the transmountain region and the Tibetan plateau. The values are highest in the mountain region, followed by the hills and Indo-Gangetic Plains. Approximately 65% of average annual precipitation is converted to flows, indicating high water availability. Actual evapotranspiration is highest in the Indo-Gangetic Plains region due to the presence of irrigated agriculture and a few forested mountain watersheds. As most of the water from the mountain and hill regions eventually flows down to the plains, the mountain and hill regions in Nepal are important for maintaining agriculture in the plains in both Nepal and India. Results from the flow analyses indicate the high temporal variability of flows in the basin. The frequent occurrences of both high- and low-flow events demonstrate the existing vulnerability of the region to both floods and droughts, leading to a very risk-prone livelihood system. Climate change projections show an increasing trend in precipitation and net water yield for most of the basin, except the transmountain region. Therefore, it is important to consider the climate change impacts on water resources in future planning.

Using biophysical and social analysis methods, this paper evaluated agricultural practices under changing climate in the Koshi Basin and assessed adaptation options. Agricultural trend analysis showed that in the recent three to four decades, the total cultivated area had declined in all parts of the basin except in the Nepal Mountain Region. Household survey results also confirmed such decline and further revealed shifts towards non-agricultural activities. Climate trend analysis showed changes in the frequency of wet and dry days in study districts, implying an increasing chance of flood and drought events. Household surveys further revealed that, in general, people perceived a decline in agricultural water availability and an increase in drought and flood events. The direct impacts of these changes were reduced crop yield, increased fallow lands, displacement of people from settlement areas, sedimentation of cultivable land and damage to properties. Household surveys showed that despite the perceived i...

Many rural communities in Nepal experience considerable water stress during the dry season. Water storage systems (WSSs) have been proposed to supplement rain-fed irrigation and augment domestic water services in these communities. We evaluate household preferences for WSSs using a choice experiment and latent class modeling techniques. Results indicate the presence of three classes. The majority of households (≈92%) belong to two equally-sized classes, a relatively privileged group (i.e. wealthier, better educated, etc.) with strong preferences for supplemental irrigation and a less privileged group that is mainly interested in improved domestic water services. The remaining class’ preferences are dominated by the cost attribute and are consistent with households facing severe cash constraints. Estimated welfare effects reveal that WSSs disproportionately benefit the privileged, although this disparity is mitigated with the provision of domestic water. These findings highlight the potential welfare gains from WSS investments, but stress the need for multi-purpose water resource development and the potential for elite capture.

Study region Karnali-Mohana river basin, Western Nepal. Study focus This study aims to project future climate and assess impacts of climate change (CC) on water availability in the Karnali-Mohana (KarMo) basin. Bias-corrected future climate was projected based on ensembles of multiple models selected from a set of 19 regional climate models (RCMs). The impacts on water availability were then assessed by forcing a well calibrated and validated hydrological model with projected future precipitation (P) and temperature (T) for various climatic scenarios. New hydrological insights for this region Results showed that future T is projected to increase spatio-temporally with higher rate for the mountain stations in the winter season; whereas future P has no distinct spatio-temporal trend but increase in dry season precipitation for future periods. The projected changes in P, T and evapotranspiration are expected to alter average annual flow at the outlets of the KarMo and its sub-basins, albeit with varying rate. The simulated results showed higher impacts in water availabilty at higher altitudes, thus indicating higher vulnerability of northern mountainous region to CC than the southern flatlands. Being the first ever study of such nature in the study area, these results will be useful for planning and development of climate-resilient water development projects in the region.

Study region Karnali-Mohana (KarMo) river basin, Western Nepal. Study focus This study has developed a hydrological model using multi-site calibration approach for a large basin, the Karnali-Mohana (KarMo) in Western Nepal, which has a lot of potential for water resources development and contribute to the national prosperity. It further applies the model to characterize hydrology and water resources availability across spatio-temporal scales to enhance understanding on water availability and potential uses. The newly developed hydrological model in Soil and Water Assessment Tool (SWAT) is capable of reproducing the hydrological pattern, the average flows, and the flow duration curve at the outlet of the basin and five major sub-basins. New hydrological insights for this region The model simulated results showed that about 34 % of average annual precipitation in the KarMo basin is lost as evapotranspiration, but with a large spatio-temporal heterogeneity. The Hills and Tarai are relatively wetter than the Mountains. The average annual flow volume at the basin outlet is estimated as 46,250 million-cubic-meters (MCM). The hydrological characterization made in this study are further used for climate change impact assessment (Part-B in the same journal), environmental flows assessment and evaluating trade-offs among various water development pathways, which are published elsewhere. This model, therefore, has potential to contribute for strategic planning and sustainable management of water resources to fuel the country’s prosperity.

Water diversion projects across the world, for drinking water, energy production and irrigation, have threatened riverine ecosystems and organisms inhabiting those systems. However, the impacts of such projects on aquatic biodiversity in monsoon-dominated river ecosystems are little known, particularly in Nepal. This study examines the effects of flow reduction due to water diversion projects on the macroinvertebrate communities in the rivers of the Karnali and Mahakali basins in the Western Himalayas in Nepal. Macroinvertebrates were sampled during post-monsoon (November), baseflow (February) and pre-monsoon (May) seasons during 2016 and 2017. Non-metric Multidimensional Scaling (NMDS) was performed to visualize clustering of sites according to percentage of water abstractions (extraction of water for various uses) and Redundancy Analysis (RDA) was used to explore environmental variables that explained variation in macroinvertebrate community composition. A significant pattern of macroinvertebrates across the water abstraction categories was only revealed for the baseflow season. NMDS clustered sites into three clumps: “none to slight water abstraction ( 30% to 80% – Class 3)”. The study also showed that water abstraction varied seasonally in the region (Wilk’s Lambda = 0.697, F(2, 28) = 4.215, P = 0.025, n2 = 0.23). The RDA plot indicated that taxa such as Acentrella sp., Paragenetina sp., Hydropsyche sp., Glossosomatinae, Elmidae, Orthocladiinae and Dimesiinae were rheophilic i.e. positively correlated with water velocity. Taxa like Torleya sp., Caenis sp., Cinygmina sp., Choroterpes sp., Limonidae and Ceratopogoniidae were found in sites with high proportion of pool sections and relative high temperature induced by flow reduction among the sites. Indicator taxonomic groups for Class 1, 2 and 3 water abstraction levels, measured through high relative abundance values, were Trichoptera, Coleoptera, Odonata and Lepidoptera, respectively. Macroinvertebrate abundance was found to be the more sensitive metric than taxonomic richness in the abstracted sites. It is important to understand the relationship between flow alterations induced by water abstractions and changes in macroinvertebrates composition in order to determine sustainable and sound management strategies for river ecosystems.

Planning adaptation strategies in response to climate change (CC) can be a daunting task, especially in regions such as the Koshi Basin in the Himalayas, where CC impacts are still uncertain. This paper recommends targeting adaptation strategies by focusing on changes in variability between the past and future climates at smaller scales. The Soil and Water Assessment Tool (SWAT) and the Indicators of Hydrologic Alteration (IHA) are used for analysis. The results show: (a) higher maximum precipitation during monsoon and post-monsoon, and lower maximum precipitation during winter; (b) increase in precipitation and flows in the Trans-mountain region during all seasons, except for flows during monsoon; (c) increase in post-monsoon precipitation and routed flow volumes; (d) decrease in precipitation during winter and routed flow volumes in all the regions, except the Trans-mountain region; and (e) increase in frequency of high peak flows and decrease in baseflows. Editor Z.W. Kundzewicz Associate edito...

The water resources of the Koshi Basin (87,311 km2) are largely untapped, and while proposals for their development exist, their impacts on current and future water demand are not quantified. The current study is the first to evaluate the impacts of 11 proposed development projects for hydropower generation and water storage. We find that 29,733 GWh of hydropower could be generated annually and 8382 million m3 of water could be stored. This could satisfy unmet demand in the current (660 million m3) basin situation and in future scenarios – i.e. population, agricultural and industrial growth – that are projected to have 920, 970 and 1003 million m3 of unmet demand, respectively, by 2050.

Integrated water resources management (IWRM) has been prescribed in the global water policy literature for decades. This article looks at how the concept has been applied in Nepal. It highlights the normative approach in IWRM policy formulation, the existing institutional barriers to apply it and how these resulted in the framing of IWRM ‘implementation’ as merely a compilation of donor-funded projects. Current discourse on IWRM highlights the need to shift the emphasis from national policy formulation to local adaptive, pragmatic approaches to IWRM. This article brings to light the need to identify potential entry points to scale up locally rooted water management approaches towards the development of nested institutional set-ups in water resources management.

Water has been identified as a key resource for Nepal's economic growth. Although the country has 225 billion cubic meters of water available annually, less than 7% has been utilized. Climate change is a frequent topic in national development discussions in part because of its possible impact on future water availability. This study assessed the likely impact of climate change on water resources development in the Koshi River basin, Nepal, using the Soil and Water Assessment Tool to generate projections for the 2030s and 2050s. Results suggested that the impacts are likely to be scale dependent. Little impact is projected at annual, full-basin scales; but at sub-basin scale, under both the IPCC's A2 and B1 scenarios, precipitation is projected to increase in the upper transmountain subwatersheds in the 2030s and in most of the basin in the 2050s and to decrease in the lower sub-basins in the 2030s. Water yield is projected to increase in most of the basin except for the A2 scenario for the 2030s....

The rituals of riparian communities are frequently linked to the flow regimes of their river. These dependencies need to be identified, quantified and communicated to policy makers who manage river flows. This paper describes the first attempt to explicitly evaluate the flows required to maintain the cultural and spiritual activities in the upper Ganga River basin. Riparian dwellers and visitors were interviewed and the responses analyzed to obtain an overview of the needs and motivations for cultural flows. The approach enhances the overall concept of environmental flow assessment, especially in river basins where spiritual values ascribed to rivers are high.

Since the 1990s, Indian farmers, supported by the government, have partially shifted from surface-water to groundwater irrigation in response to the uncertainty in surface-water availability. Water-management authorities only slowly began to consider sustainable use of groundwater resources as a prime concern. Now, a reliable integration of groundwater resources for water-allocation planning is needed to prevent aquifer overexploitation. Within the 11,000-km(2) Musi River sub-basin (South India), human interventions have dramatically impacted the hard-rock aquifers, with a water-table drop of 0.18 m/a over the period 1989-2004. A fully distributed numerical groundwater model was successfully implemented at catchment scale. The model allowed two distinct conceptualizations of groundwater availability to be quantified: one that was linked to easily quantified fluxes, and one that was more expressive of long-term sustainability by taking account of all sources and sinks. Simulations showed that the latter implied 13 % less available groundwater for exploitation than did the former. In turn, this has major implications for the existing water-allocation modelling framework used to guide decision makers and water-resources managers worldwide.

Allocation of water to cities, industries and agriculture has been a common practice in river basin planning and management. It is widely accepted that water also needs to be allocated for the aquatic environment, i.e. alongside the demands of other users. This paper describes the application of a basin planning model (Water Evaluation and Planning Model) to assess present and alternative water management options, which include incorporation of environmental flows (EFs) in the Upper Ganges River, India. Furthermore, the impacts of projected climate changes are also considered. The paper also briefly summarizes the EF assessment methodology, which was conducted through a multidisciplinary, multi-stakeholder approach (Building Blocks methodology). This is the first time that a comprehensive EF assessment has been done in India. Results from this study show that annual water demands for the domestic, industrial and irrigation water use are 1375, 1029 and 6680 MCM, respectively. Unmet demands, i.e. when there is not enough water to fulfil the required demands, were a problem during December and January for the past climate and during December, January and February under climate change-projected conditions. Adding EFs increased unmet demands in the same winter months. During March–November, unmet water demands were less than 5 MCM even with the addition of EFs. Reducing crop type to less water intense crops was more effective in reducing unmet demands than decreasing the cropped area. Improving irrigation systems through improved efficiency and water saving technologies as well as conjunctive use of surface and ground water is also viable options. However, the most effective water management solution is from managing upstream storage structures such as the Tehri dam for increased dry season flows. Dry season releases from Tehri dam can be used to reduce the downstream unmet demands, which include EFs to less than 5 MCM/month. Copyright © 2013 John Wiley & Sons, Ltd.

This paper assesses the potential loss of irrigation benefits in reallocating water from irrigation to meet requirements for environmental flows (e-flows) in the Upper Ganga Basin (UGB) in northern India. The minimum requirement for e-flows in the UGB is 32 billion cubic meters (BCM), or 42 % of the mean annual runoff. The current runoff during the low-flow months falls below the minimum requirement for e-flows by 5.1 BCM. Depending on irrigation efficiency, reallocation of 41–51 % of the water from canal irrigation withdrawals can meet this deficit in minimum e-flows. The marginal productivity of canal irrigation consumptive water use (CWU), estimated from a panel regression with data from 32 districts from 1991 to 2004, assesses the potential loss of benefits in diverting water away from crop production. In the UGB, canal irrigation contributes to only 8 % of the total CWU of 56 BCM, and the marginal productivity of canal irrigation CWU across districts is also very low, with a median of 0.03 USD/m3. Therefore, at present, the loss of benefits is only 1.2–1.6 % of the gross value of crop production. This loss of benefits can be overcome with an increase in irrigation efficiency or marginal productivity.

Assessment of surface and groundwater resources and water availability for different sectors is a great challenge in Nepal mainly due to data limitations. In this study, the Soil Water Assessment Tool (SWAT) was used to simulate the hydrology and to calculate sub-basin wise water balances in the Koshi Basin, Nepal. The impacts of Climate Change (CC) projections from four GCMs (CNRM-CM3, CSIRO-Mk3.0,ECHam5 and MIROC 3.2) on the hydrology of the basin were also calculated. This paper summarizes some of the key results. The full report of the study is in preparation.The basin can be divided into the trans-mountain, central mountain, eastern mountain, eastern hill and central hill regions. Results show that current precipitation is highest in the central mountain and eastern mountain regions during both the dry and wet seasons. Water balance results showed that Actual ET as well as Runoff is also highest in the central and eastern mountain regions followed by the mid-hills. Results from climate change projections showed that average temperature will increase in the 2030’s by 0.7-0.9° Celsius. Results for 2030s projections also show that during the dry season, precipitation increases in the trans-mountain but decreases in the other regions for both A2 and B1 scenarios. During the wet season, the MarkSim projections show a decrease in precipitation in all the regions. Net water yields also increased for the trans-mountain zone during the dry season but show varying results during the monsoon. Assessment of projected future flow time series showed that there will be an increase in the number of extreme events; i.e., both low flows and large floods. There is however; a high degree of uncertainty in the projected climate data as the relative standard deviation was quite high.DOI: http://dx.doi.org/10.3126/hn.v11i1.7198 Hydro Nepal Special Issue: Conference Proceedings 2012 pp.18-22

The Melamchi Water Supply Project (MWSP) is designed to minimize the shortage of drinking water in the Kathmandu valley. Although the project was supposed to be completed by 2008, due to various problems, it is still difficult to forecast the exact date of completion. This paper quantifies the downstream effects of diverting water from the Melamchi (Stage-I), Yangri (Stage-II) and Larke (Stage-III) rivers under current as well as future climate scenarios. The Soil Water Assessment Tool (SWAT) was used in the analysis. Result shows that in the Stage-I water transfer plan, average inflow reduction in the immediate downstream sub-basin in the dry and wet seasons are 36% and 7% respectively, where as in Stage-II the inflow reductions are 38% for the dry season and 8% for the wet season. In Stage-III, inflow reductions are 38% in the dry season and 7% in the wet season.The impact of the water transfer schemes on various changes in water management within the Melamchi River irrigation command area was also tested. BUDGET (soil, water and salt balance) model was used to quantify crop water requirement of Melamchi River command area when the irrigated area is increased and the cropping pattern is changed. Simulation results of crop water requirement in intensive water use conditions show that present Melamchi River command area can be increased by 2.2 times under current climate projection, whereas the area can be increased 1.4 times in 2030s and by 2.0 times in 2050s.DOI: http://dx.doi.org/10.3126/hn.v11i1.7199 Hydro Nepal Special Issue: Conference Proceedings 2012 pp.23-29

Climate change is one of the drivers of change in the Ganges River Basin, together with population growth, economic development and water management practices. These changing circumstances have a significant impact on key social and economic sectors of the basin, largely through changes in water quantity, quality and timing of availability. This paper evaluates the impact of water on changing circumstances in three sectors of the Ganges Basin – agriculture, ecosystems and energy. Given the inherent interconnectedness of these core sectors and the cross-cutting impact of changing circumstances on water resources, we argue that adaptation should not be viewed as a separate initiative, but rather as a goal and perspective incorporated into every level of planning and decision making. Adaptation to changing circumstances will need to be closely linked to water resource management and will require significant collaboration across the sectors.

Demand-based irrigation systems are operated according to crop water requirements. As crop water requirements remain variable throughout the growing season, the discharges in the canal also vary to meet demands. The irrigation system under study is a demand-based semi-automatic irrigation system, where flows in the main canal are automatically controlled and secondary canals manually operated. The main canal headworks have been equipped with the SCADA system with proportional integral (PI) discharge controllers and the canal itself has been provided with self-regulating AVIS/AVIO downstream control gates for flow regulation in the canal. The secondary canals have manually operated sliding gates, which are opened or closed as per crop water requirements of the command area following a crop-based irrigations operation (CBIO) schedule under which they remain closed for one week after one or several weeks open, depending upon water needs. The flow in the main canal is then automatically adjusted according to the number of open or closed secondary offtakes. These operations result in fluctuating flows in the main canal and if not properly planned can cause serious implications for canal safety and its hydrodynamic performance. The PI discharge controllers regulate discharge releases to the canal in order to satisfy demands. The proper selection of PI coefficients ensures system safety and efficient water delivery. The operation of the secondary canals also plays a key role in defining the performance of the automatic operations. The planned opening and closure of a cluster of offtakes ensures safety of the self-regulating structures and stability of the flows in the main canal. In this paper various options have been tested using hydrodynamic modelling and we found some optimal values of PI coefficients and defined some rules for secondary canal operations to enhance the operational performance and sustainability of downstream-controlled irrigation canals.

This study looks at the changes in water balance in the Gorai River Catchment in the Bangladesh delta before and after operationalization of Farakka Barrage. Results show that inflow into the catchment has decreased, but major changes in land use within the catchment have also impacted runoff. Model scenarios demonstrate that although increasing inflow from upstream is the most effective method to increase dry season flows into the delta, reduction in cultivation of water-intensive crops would provide an alternative solution.

The basins of the Indus and Ganges rivers cover 2.20 million km2 and are inhabited by more than a billion people. The region is under extreme pressures of population and poverty, unregulated utilization of the resources and low levels of productivity. The needs are: (1) development policies that are regionally differentiated to ensure resource sustainability and high productivity; (2) immediate development and implementation of policies for sound groundwater management and energy use; (3) improvement of the fragile food security and to broaden its base; and (4) policy changes to address land fragmentation and improved infrastructure. Meeting these needs will help to improve productivity, reduce rural poverty and improve overall human development.

As demand and competition for water resources increase, the river basin has become the primary unit for water management and planning. While appealing in principle, practical implementation of river basin management and allocation has often been problematic. This paper examines the case of the Krishna basin in South India. It highlights that conflicts over basin water are embedded in a broad reality of planning and development where multiple scales of decisionmaking and non-water issues are at play. While this defines the river basin as a disputed "space of dependence", the river basin has yet to acquire a social reality. It is not yet a "space of engagement" in and for which multiple actors take actions. This explains the endurance of an interstate dispute over the sharing of the Krishna waters and sets limits to what can be achieved through further basin water allocation and adjudication mechanisms – tribunals – that are too narrowly defined. There is a need to extend the domain of negotiation from that of a single river basin to multiple scales and to non-water sectors. Institutional arrangements for basin management need to internalise the political spaces of the Indian polity: the states and the panchayats. This re-scaling process is more likely to shape the river basin as a space of engagement in which partial agreements can be iteratively renegotiated, and constitute a promising alternative to the current interstate stalemate.

In closing river basins where nearly all available water is committed to existing uses, downstream irrigation projects are expected to experience water shortages more frequently. Understanding the scope for resilience and adaptation of large surface irrigation systems is vital to the development of management strategies designed to mitigate the impact of river basin closure on food production and the livelihoods of farmers. A multilevel analysis (farm-level surveys and regional assessment through remote-sensing techniques and statistics) of the dynamics of irrigation and land use in the Nagarjuna Sagar project (South India) in times of changing water availability (2000–2006) highlights that during low-flow years, there is large-scale adoption of rainfed or supplementary irrigated crops that have lower land productivity but higher water productivity, and that a large fraction of land is fallowed. Cropping pattern changes during the drought reveal short-term coping strategies rather than long-term evolution...