Gandaki River Basin Research Articles

Hydro-climatic trends and people’s perceptions: case of Kali Gandaki River Basin, Nepal

Water resources, especially snow-fed rivers, are vulnerable to climate change. Water resources management requires analysis of both hydro-climatic trends and people's perception of climate change. We used available data to assess hydro-climatic trends, and household surveys to assess perceptions of climate change and its effects, in the snow-fed Kali Gandaki River Basin (KGRB) in western Nepal. The methodology consisted of: (1) definition and calculation of climate variability indices, (2) assessment of people's perception of climate change, (3) analysis of river flow variability and (4) discussion and summary of the spatial variation in climatic trends, peoples' perceptions, and the effects of climate change. The results showed a greater warming trend at higher altitude, while precipitation indices showed variable trends. Increasing temperature at high altitudes has affected pre-monsoon, post-monsoon and minimum discharges in the Kali Gandaki River. Household surveys in the Mustang district indicate that people's perception of climate change is consistent with climate data. They are concerned about the prevailing effects on water resources, ecological systems, agriculture and livelihoods. This will facilitate water resources planning and management in the basin.

Perturbation study of climate change impacts in a snow‐fed river basin

AbstractA physically based distributed hydrological model developed at the University of Yamanashi based on block‐wise use of TOPMODEL and the Muskingum–Cunge method (YHyM/BTOPMC), integrated with a simple degree‐day–based snow accumulation/melt sub‐model, was applied to evaluate hydrological responses under changing climatic conditions in the snow‐fed Kali Gandaki River Basin (KGRB) in Western Nepal. Rainy season precipitation (June to September) in the basin takes up about 80% of the annual precipitation, and dry season runoff is largely contributed by snowmelt. Climate change is likely to increase the probability of extreme events and problems related to water availability. Therefore, the study aimed to simulate runoff pattern under changing climatic conditions, which will be helpful in the management of water resources in the basin. Public domain global data were widely used in this study. The model was calibrated and validated with an acceptable degree of accuracy. The results predicted that the annual average discharge will increase by 2.4%, 3.7%, and 5.7% when temperature increases by 1, 2, and 3 °C compared with the reference scenario. Similarly, maximum, minimum, and seasonal discharges in the monsoon and pre‐monsoon seasons will also increase with rising temperature. Snowmelt runoff is found sensitive to temperature changes in the KGRB. Increasing temperature will cause a faster snowmelt, but precipitation will increase the snowpack and also shed a positive effect on the total annual and monsoonal discharge. For the combined scenarios of increasing temperature and precipitation, the annual average discharge will increase. In contrast, discharge during the increasing temperature and decreasing precipitation will tend to decrease. Copyright © 2012 John Wiley & Sons, Ltd.

Application of Water Poverty Index (WPI) in Nepalese Context: A Case Study of Kali Gandaki River Basin (KGRB)

This article details an application of Water Poverty Index (WPI) to evaluate state of water resources in the context of Nepalese river basins with a case study of Kali Gandaki River Basin (KGRB) located in western Nepal. Considering that water poverty issues and indicators to represent them are location-specific, selecting suitable indicators with due care of local context and data availability is essential to apply the WPI, a holistic tool for water resources planning and management. In this study, it suggests and describes a set of ten WPI indicators and twelve variables suitable in the Nepalese context. The selected set of indicators and variables is used to discuss water poverty situation in the study basin as a whole, spatial variation within the basin and variation at different spatial scales in the basin, that is, basin, sub-unit of the basin (district) and sub-unit of the district (Village Development Committee (VDC)). The study result shows that WPI varies widely (from 37.1 to 56.5) within the study basin suggesting the need of location-specific policy interventions. At different spatial scales, there is no clear trend; however, analysis of the WPI components shows higher resources and access at basin level; higher use, environment and capacity at sub-sub-unit of the basin level. Such variations suggest the need of scale-specific policy interventions and management plans to improve overall water poverty situation in the study basin. Overall, the WPI helped to examine the water poverty situation and recommend priority areas of policy interventions for the improvement of water-poverty situation in the basin.

RESERVOIR OPERATION ANI EVALUATION OF DOWNSTREAM FLOW AUGMENTATION1

ABSTRACT: Operation of a storage‐based reservoir modifies the downstream flow usually to a value higher than that of natural flow in dry season. This could be important for irrigation, water supply, or power production as it is like an additional downstream benefit without any additional investment. This study addresses the operation of two proposed reservoirs and the downstream flow augmentation at an irrigation project located at the outlet of the Gandaki River basin in Nepal. The optimal operating policies of the reservoirs were determined using a Stochastic Dynamic Programming (SDP) model considering the maximization of power production. The modified flows downstream of the reservoirs were simulated by a simulation model using the optimal operating policy (for power maximization) and a synthetic long‐term inflow series. Comparing the existing flow (flow in river without reservoir operation) and the modified flow (flow after reservoir operation) at the irrigation project, the additional amount of flow was calculated. The reliability analysis indicated that the supply of irrigation could be increased by 25 to 100 percent of the existing supply over the dry season (January to April) with a reliability of more than 80 percent.

Immunoglobulin allotypes in peoples from five villages in Nepal

Serum samples from people living in three villages (Simikot, Thymkyn and Yakba) in the Karnali River basin in extreme northwest Nepal and from people living in two villages (Dangrizong and Phalag) in the upper Kali Gandaki River basin in central Nepal were tested for the immunoglobulin allotypes Gm (1,2,3,5,6,10,11,13,14,17,21,24,26) and Inv(Km)(1). The people from one of the villages (Simikot) are Caucasoid in appearance and have cultural, linguistic and religious ties to southern Nepal and India. Those from the four other villages are Mongoloid in appearance and have cultural, linguistic and religious ties to Tibet. The Gm phenotype and haplotype arrays and Inv1 frequency for the samples from Simikot were, as expected, typically Caucasoid. The samples from Thymkyn and Yakba, on the other hand showed no evidence of being from Mongoloid and not Caucasoid individuals, except for the absence of Gm(3,5,10,11,13,14,26) samples. Their phenotypes could be explained by postulating either the Gm3,5,10,11,13,14,26 haplotype found among Caucasoids or the Gm1,3,5,10,11,13,14,26 haplotype found among Mongoloids. The latter is assumed to be present, because of the Mongoloid appearance of the donors of the samples. Larger numbers of samples, preferably from families, are needed to decide which of these alternatives is correct. The Gm haplotype and Inv1 frequencies of the samples from people in Dangrizong and Phalag villages are typically Mongoloid and significantly different from those for the samples from people in Thymkyn and Yakba. The frequencies for samples within the pairs of villages were the same. Whether these data indicate a cline or genetic drift can be determined on the basis of the comparison of data for samples from populations residing between the locations from which the samples were drawn for this study with samples from the two regions already studied. Larger numbers of samples from the two regions already studied are desirable and all samples should be analysed for additional polymorphisms.

Changing Climatic Parameters and its Possible Impacts in Hydropower Generation in Nepal (A Case Study on Gandaki River Basin)

The analysis of water resources in Nepal identifies two critical impacts of climate change –GLOFs and variability of river runoff – both of which pose significant impacts not only to hydropower, but also to rural livelihoods and agriculture. Temperature differences are most pronounced during the dry winter season, and least during the height of the monsoon. Impacts on water resources and hydropower rank significantly higher than any other sector for several reasons. First, a number of impacts on water resources and hydropower are directly related to rising temperatures that have already been observed, and are projected to increase further over the coming decades. This includes glacier retreat that in turn causes both greater variability in stream flow and glacial lake outburst floods that pose significant risk to hydropower facilities, other infrastructure, and human settlements. GLOFs are not hypothetical; such events have already had significant impacts in Nepal. In this study over the Gandaki river basin, discharge of the rivers, temperature trends, and rainfall patterns are analyzed using data from meteorological stations of the Department of Hydrology and Meteorology (DHM), Government of Nepal. Similarly the hydrological stations over the major glacier rivers of the basin are examined. In the study area, some hydropower stations and their energy production fluctuations over the seasons reflect the climate change impact to the hydro energy production in Nepal.Key words: Climate change; GLOF; Hhydropower; DHMDOI: http://dx.doi.org/10.3126/jie.v8i1-2.5108Journal of the Institute of Engineering Vol. 8, No. 1&2, 2010/2011Page: 160-173Uploaded Date: 20 July, 2011