Assessment of aquatic plants evapotranspiration for secondary agriculture drains (case study: Edfina drain, Egypt)

摘要

This research was set in order to estimate aquatic plants evapotranspiration, (ET) in Edfina drain, Nile Delta, Egypt, which had an in-stream treatment wetland that was taken as a case study. A simple field scale approach is presented to measure drain water evaporation and water consumption of five aquatic plants, cultivated in floating tanks. Plants ET, (ET p ) values were obtained by measuring the daily quantity of water required to renovate the tank’s initial volume. Crop coefficients ( K c ) were obtained and water loss from the drain wetland was calculated due to evaporation and plants cells ET p . Results presented values of ET p and K c which were controlled by plant leaf area and growing stage. The major ET p was for Hyacinth followed by Cattail, Reeds, Torpedo grass, and then duckweeds. All ET p values exceeded twice the adjacent non-vegetated water evaporation. The obtained K c values referenced to the drain water evaporation were almost twice the K c values of FAO Penman–Monteith ET, due to the landscape effects, as hot dry air can cause extra heat input and water loss. Total losses from in-stream treatment series of pond, 4 plants reaches and open disinfection zone did not exceed 0.55% of drain discharge.