Impact of Climate Change on Naulsing Gad Storage Hydropower Project (410 MW), Jajarkot

Abstract

Nepal is going through an unprecedented deficit of electrical power particularly in dry season. This is mainly due to the lack of reservoir type hydropower projects. For the reservoir project, the impact of climate change should be incorporated during planning, design & implementation for long term sustainability and effectivity. The past recorded data analysis and projected future data analysis is essential to draw relevant conclusions. Climate change study in long term aspect is very important to maximize the benefit from any reservoir project. Prediction of future flow scenarios using models like HEC-HMS model developed by Hydrologic Engineering Center, US Army Corps of Engineers, a numerical models is essential and is used for the climate change impact study of Naulsing Gad Storage Hydropower Project. The simulation was performed on different Scenario of long term average flow for the period of 2015-2100. Naulsing Gad scheme being a single purpose reservoir project, simulation was carried out with a lone objective of assessing and maximizing the project benefits in long run incorporating the climate change impact on the basin. The flow scenarios in immediate future(2015-2044), mid-term future(2045-2074) and long term future(2075-2104) was predicted using HEC-HMS model and flow trend, maximum, minimum, Q40, flood analysis & energy change trend analysis was performed for all RCP scenarios. Furthermore, the past recorded data of discharge precipitation and temperature of projected area was also analyzed and past trend and projected future trend was compared. HEC-HMS, the simulation model used in this study, performed quite robustly in simulating future operation discharge. The future discharge in all RCP scenario is found to be increasing and also future flood & energy is increasing in most cases. Past data also showed increasing trend of extreme precipitation and temperature in most stations. So, impact of climate change on river flow considered in this study is of indicative nature and hence should be given almost importance in any further planning, design and implementation of Naulsing Gad Storage HEP for long term sustainability & effectivity.