Assessment of Water Productivity in RD43 Rice Cultivation under the Don Chedi Water Delivery and Maintenance Project

Abstract

The Don Chedi Operation and Maintenance Project is an Irrigation Project that utilizes two distinct water delivery methods because water sources are used for water delivery differently: Irrigation water delivery from the Greater Chao Phraya Project by using gravity irrigation managed by Operation and Maintenance Division 1 and electrically pumped irrigation from Chorakhe Sam Phan Canal managed by Operation and Maintenance Division 2, which incurs annual energy costs for the Royal Irrigation Department. This study aims to assess the water productivity of RD43 rice cultivation during the 2023 wet and dry seasons in two representative study areas: Canal 12 Left M.-A. (gravity irrigation managed by Operation and Maintenance Division 1) and Canal 21 Left M.-A. (electrically pumped irrigation managed by Operation and Maintenance Division 2). Results indicate that in the wet season, Canal 12 Left M.-A., covering 4,594 rai, exhibited a total water productivity of 0.45 kg/m³, with an irrigation water productivity of 0.36 kg/m³, rainfall water productivity of 0.97 kg/m³ and economic water productivity of 2.43 THB/m³ Meanwhile, Canal 21 Left M.-A., covering 3,285 rai, demonstrated a total water productivity of 0.49 kg/m³, with an irrigation water productivity of 0.25 kg/m³, rainfall water productivity of 1.85 kg/m³ and economic water productivity of 2.57 THB/m³.

During the dry season, Canal 12 Left M.-A., with a cultivated area of 1,453 rai, exhibited a total water productivity of 0.53 kg/m³, with an irrigation water productivity of 0.38 kg/m³, and a rainfall water productivity of 2.54 kg/m³. And economic water productivity of 3.17 THB/m³. Meanwhile, Canal 21 Left M.-A., covering 2,259 rai, demonstrated a total water productivity of 0.54 kg/m³, with an irrigation water productivity of 0.34 kg/m³, rainfall water productivity of 3.50 kg/m³, and economic water productivity of 3.10 THB/m³.