Analyzing rainfall events and soil characteristics for water resources management in a canal irrigated area.

Abstract

Rainfall analysis is essential for water resources management and crop planning. An attempt has been made to analyse the rainfall of Daspalla region in Odisha, eastern India for prediction of monsoon and post-monsoon rainfall by using 6 different probability distribution functions, forecasting the probable date of onset and withdrawal of monsoon and finally crop planning for the region. Soil parameters were assessed for head, mid and tail reaches of the command area. Results revealed that, for prediction of monsoon and post-monsoon rainfall, Log Pearson Type-III and Gumbel distribution are found as the best fit probability distribution functions. The earliest and delayed most week of onset of rainy season was 20th SMW (14-20th May) and 25th SMW (18-24th June), respectively. Similarly, the earliest and delayed most week of cessation of rainy season was 39th SMW (24-30th September) and 47th SMW (19-25th November) respectively. The soils have the clay contents ranging from 29.6 to 48.8%. The bulk density ranged from 1.44 to 1.72 Mg.m-3 irrespective of different sites. The saturated hydraulic conductivity decreased significantly with soil depth due to greater clay contents in lower layers; whereas water retention at field capacity and PWP increased significantly with increase in soil depths. Soil organic carbon varied from 0.34 to 0.95%; it was the highest in the surface (0-15 cm) layer and then decreased down to the soil profile. The results of rainfall analyses and soil properties would help in management of rainfall and canal water in an effective way.