STOCHASTIC ANALYSIS OF DAILY RAINFALL DATA BETWEEN BARGI AND HOSHANGABAD IN NARMADA BASIN

Abstract

The amount of rainfall received over an area is an important parameter for assessing the amount of water available for various uses such as domestic, agricultural, industrial, water supply, generation of hydropower, ground water recharge and navigation etc. Hydrological processes in general and rainfall process in particular are random in space and time due to change in catchments and erratic behavior of atmosphere. Distribution of rainfall within a year varies widely from year to. year. Rainfall is the primary source of water to any hydrologic system. Runoff estimated using rainfall is often used in design of the capacity of the reservoir and in planning the cropping pattern and reservoir operations. Flood discharge values estimated using daily rainfall are used in design of spillway structure. Hence, rainfall records are of great importance in hydrology. While monthly data are sufficient for reservoir planning, rainfall data pertaining to small durations like a day are necessary in design concerning micro catchments and structures like check dams, irrigation water requirements, water supply tanks for a small community or tank for roof water harvesting in individual houses. A study has been taken to understand the behavior of rainfall occurrence in space and time. For this, monthly rainfall data of Hoshangabad, Silwani, Sohagpur, Betul, Sarni dam, Udaipura, Narsingpur, Lakhandon, Adhartal, Patan and Bahoribund stations for the period 1901-1950 and from 1981 onwards have been used for the analysis. Daily rainfall data of period from 1981 to 1991 have also been analysed for studying the structure of spatial correlation over the area between Bargi & Hoshangabad in Narmada basin and examining the temporal characteristics of daily rainfall data. Thus, in this study, time series analysis, monthly simulation of rainfall, temporal-spatial characteristics of rainfall and frequency analysis of one-day rainfall have been carried out. Homogeneity of annual rainfall series of two discontinuous periods has been carried out using Buishand test at 5% significance level. Four stations namely Sohagpur, Narsingpur, Lakhandon and Patan have shown non-homogeneity in terms of jump in annual rainfall series. The randomness of annual rainfall series has been tested using turning point test and Anderson's correlogram test. The analysis did not indicate any persistence or non-randomness in the series.