Extreme rainfall analysis for an agricultural land drainage system

Abstract

ABSTRACT The present study highlights the IS 8835:1978 recommendation for the planning and design of surface agricultural drains adopted uniformly across India. The current analysis aimed to compute the agricultural land drainage design and cross-drainage structure for 5-year and 50-year frequencies, respectively, using 3-day rainfall for the areas belonging to three different agro-climatological zones (including four districts, i.e. Surat, Ahmedabad, Jaipur and Mumbai). Extreme rainfall analysis using 3-day fixed window (FW) and sliding window (SW) rainfall was carried out using the probabilistic approach and the maximum rainfall depth-duration-frequency curves. For the 5-year (50-year) frequency, the 3-day FW rainfall for Surat, Ahmedabad, Jaipur, and Mumbai was 303 mm (490 mm), 235 mm (442 mm), 147 mm (326 mm), and 417 mm (667 mm), respectively, whereas the 3-day SW rainfall is 345 mm (583 mm), 258 mm (473 mm), 168 mm (359 mm), and 485 mm (765 mm), respectively. The trend analysis results showed the non-monotonous increasing (decreasing) trend over study regions. The SW rainfall was higher than the corresponding FW values. The results presented in this study can be adopted in the design of the agricultural land drainage network and cross-drainage structure in the regions under consideration.