Analysis of Spatial and Temporal Rainfall Variation in Gandaki Province, Nepal

Abstract

Daily, seasonable and annual variation on precipitation should be carried out properly to enhance the better relaxation caused by damaging drain structure, hydraulic parameters and even climatic disorder. In order to incorporate all these needs and to enhance the existing research theories and even on developing new theories, this study will surely provide basic framework. The problems for the researcher as well as meteorological department for the further study of climatic change action and to provide basic knowledge to the farmer and agricultural department to yield seasonal wise crops without consideration of hydrological analysis (i.e. precipitation data) associates problems like flood risk and drought causing loss of lives and property. For the hydrological study, daily and monthly rainfall data was obtained from meteorological station from the year 1991-2020. The monthly and daily precipitation concentration were determined using Time series analysis, single mass curve analysis, coefficient of variation and spatial analysis and were represented using Histogram chart, Spreadsheet and GIS tool. With this, daily, monthly, seasonal wise variation on precipitation with respect to location wise (Spatial) as well as Time wise (Temporal) was obtained. The temporal characteristic shows that peak month of rainfall were July and August for all the regions. Considering Total Annual, the maximum value is at Beni Bazar i.e. more than 200000mm and least in the Ranipauwa i.e less than 10000mm. The mean annual rainfall of 30 years indicating that the Beni Bazar, Myagdi region has the highest rainfall and Ranipauwa, Mustang the least. Similarly, trend analysis shows that there are increasing (+ve), decreasing (-ve) and somewhat constant trends for the different stations. Furthermore, results from variability and reliability data shows that that Ranipauwa has the highest annual variability (138.86%) and Lumle has the least annual variability (15%) in which in turn implies that the rainfall at Lumle is more reliable than other areas. The computed Spatial and Temporal variation on rainfall has been developed as a basic tool for further research. It will also help farmers to know seasonal wise crops production as well as analysis of storm water for the construction of drainage system. These findings can be considered for monitoring extreme weather events like; erosion and floods. This would therefore contribute significantly to the effective management and sustainable development of the Gandaki Province and region having similar topographical features, which are rain dependent.