Rehabilitation of operation regimes in aged irrigation schemes based on hydraulic simulation

Abstract

The selection and employment of proper methods in water distribution causes an increase in water productivity and the level of satisfaction of water users. It is faced with more difficulties in aged irrigation projects due to temporal changes such as changes in the crop patterns, development of the command area and destruction of canals and hydraulic structures. The plan of operation methods have some hydraulic and social complexities and therefore is usually simplified or implemented experimentally. This research investigates the best options for water distribution to the paddy fields in a subunit of Sefidroud irrigation scheme based on field survey, recording real data and hydraulic simulation with the employment of a SOBEK hydrodynamic model. Different operation scenarios were defined and then simulated in the current physical state of the scheme through replacing the exhausted intake structures with sluice gates. Finally, improved operation scenarios during the irrigation season were suggested based on the distribution indices. The results show that in spite of the current situation, water loss could reach the minimum by employing modification scenarios and indices of adequacy and equity of water distribution improve. HIGHLIGHTS Using Hydraulic-Numerical models to assess the operation and rehabilitation phase of an irrigation scheme.; Proposing and planning for the best operation scenarios based on the hydraulic modeling and practicability.; Investigation of re-designing some hydraulic structures and their impacts in an aged irrigation scheme using modelling.; With precise planning while less water is consumed, water distribution indices improve.;

Keywords

• fumanat region
• indices of water distribution
• irrigation canals
• operation planning
• paddy fields