Study on drainage strategy of ditch wetland in semi-arid area under the influence of inflow from the upstream irrigation area

Abstract

Salt drainage from farmlands can potentially degrade the ecological function of ditch wetlands in arid and semi-arid irrigation areas. However, such ditch wetlands may accept different quantities and salt concentrations of upstream inflows, which may have positive or negative effects on the water and salt dynamics of ditch wetland systems and, therefore, on the associated water and salt management measures. In this paper, we propose a new theoretical analysis model that enables us to study the influence of different upstream inflows on the water–salt dynamics and drainage strategies for ditch wetland in the study area. The research carried out by us has revealed that upstream inflow is one of the most important factors influencing ditch wetlands under the current conditions. An increase in salinity or a decrease in flow will negatively affect the ecology of the ditch wetland. In contrast, which will improve the ditch wetland environment. Nevertheless, wetlands are more sensitive to changes in salinity than to the volume of upstream inflow. Based on the combined effects of the salinity and quantity of its inflow on the wetlands, it can be divided into four categories: no-risk, low-risk, medium-risk, and high-risk. The inflow with no risk and low risk will have a positive effect on the ditch wetland system and drainage management, while medium-risk and high-risk conditions will increase the difficulty of drainage management, These results provide the insights needed to guide the design of drainage management practices for ditch wetlands in semi-arid regions that receive upstream inflows to maximize the benefits to the agricultural system and the environment.