Mohammad Mahmoudian - P.hD., Student of Irrigation and Drainage, Department of Water Engineering and Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran
Shiva Mohammadian Khorasani - P.hD., in Soil Engineering and Sciences, Science and Research Branch, Islamic Azad University, Tehran, Iran

Introduction: To produce the food requirements of the growing population in the world and to make optimal use of available water resources, it is necessary to increase agricultural water productivity. This can contribute to the goals of food and environmental security. Controlled drainage can be a solution to achieve higher water productivity values. Materials and methods: This study aims to summarize the evaluation of the performance of implemented drainage systems and examine their strengths and weaknesses. It can create a basis for planners and designers to have a more comprehensive view of optimal design in future plans and the effect of drainages. Results: The literature review shows that in the free drainage system, with the increase in the distance of the drains, the depth of drainage decreased and the surface runoff increased. Increasing the depth in the free drainage system caused the total amount of rainfall to penetrate the soil, and as a result, the volume of drainage increased and the amount of runoff decreased. Drains with shallow depths lead to the increased possibility of waterlogging during heavy rains. With the increase in drainage depth, the amount of the total output salt load increased significantly in both free and controlled drainage systems. Finding the best drainage design option is essential from the viewpoint of environmental and economic issues. Conclusions: The use of new drainage management technologies and consideration of environmental issues are essential for the success of drainage projects and the effective improvement of water efficiency. Today, not only modeling, designing, implementing and proper monitoring of the agricultural drainage network is important, but we have to pay attention to the special and modern issues of drainage engineering, including monitoring and safe removal of pollutants. In new drainage engineering projects, drainage and the environment should be investigated simultaneously.

Drainage management, Drainage system, Water efficiency, Waterlogging, Water productivity