Participatory Descriptive Diagram for Irrigation Management in Left Main Canal Scheme, Chiang Rai Province

Abstract

The objective of this study aimed to identify the problem statement of the irrigation system in the left main canal scheme (LMC scheme) in Chiang Rai province, which had rice as the mainly cultivated crop, through the participatory descriptive diagram (PDD). Under the system approach concept presented by Chambers (1988) and Small and Svendsen (1992), the PDD shows the relationship of irrigation systems with the components categorized into four domains (technical domain, irrigated agricultural domain, institutional domain, and financial domain). Relevant data in this research was collected by the participatory method called the participatory rural appraisal (PRA), in which quality and quantity information were collected through relevant stakeholders; 11 persons from the government sector and 22 persons from groups of water users in 2020. The PDD described the problem statement of irrigation systems in both rainy and dry seasons. In the rainy season, flooding in the main canal level was a major problem, caused by many factors, i.e., extremely lateral flow in the main canal from several natural streams from July to August, low capacity at the downstream-end section of the main canal, and inefficient drainage system. In the dry season, water scarcity was a major problem, caused by three main factors, i.e., over paddy rice cultivation with insufficient irrigation supply, incompetent management of the irrigation system of the stakeholders, and low conveyance efficiency of the canal distribution networks.