Non-Parametric Trend Analysis in South-East Regions of Uttarakhand, India

Abstract

Rainfall estimation plays a vital role in planning irrigation schedule and managing discharge through small or big dams. In the last few years, the total rainfall has been observed to be concentrated only in few rainy days. The consequence of it may be in the form of flood or stability issues on the hydraulic structures. Thus, it is important to study the spread of total rainfall in a year. In the present study, the number of rainy days for Almora district of Uttarakhand has been used. The temporal data between 1987 to 2011 was collected from India Water portal. Statistical trend detection for the data was dome using Moving Average Models, Linear Regression Models and Mann Kendall Test. In this study, trend detection has been done for all the twelve months for the said time series. Moreover, trend detection was performed for annual average rainy days for mentioned said time series. The results showed that the months of February, March, November and December, the number of rainy days showed a decreasing trend, while for the months of January, April, May, June, August, September and October showed an increasing trend. The month of July for the said time series showed no trend. Further, annual rainy days showed no significant trend. Thus, in the said time series, annually seven months had shown an increasing trend, while four months has shown decreasing trend in rainy days.