Aquatic weeds management and estimation of water losses from evapotranspiration must be taken into consideration in order to reduce water losses. The objective of this research is estimating the water losses through evapotranspiration of aquatic weeds in the Rosetta Branch in order to identify the quantities of water that could be saved when applying appropriate maintenance programs for aquatic weeds. To achieve the objective of this research, the research team identify areas of infection of the aquatic weeds using field visits, determine its coordinates using GPS and Satellite imagery (Landsat-8) and estimate of water losses through evapotranspiration of aquatic weeds by using the following evapotranspiration equation: ETc = ETo × Kc. The result for estimation of the average annual water losses through evapotranspiration of aquatic weeds in the Rosetta Branch during one year (from December 2015 to November 2016) were 21.3 million m 3 /year, 0.7 million m 3 /year and 1.1 million m 3 /year for water hyacinth, Common Reed and Torpedo grass, respectively.

Leaving out the sediments of earthen ponds for several years without disinfection or treatment leads to high concentrations of nitrogen and phosphate compounds, heavy metals and increasing sediment pollutants which release into the water. Therefore, this study aimed to evaluate the effectiveness of capping or mixing of bentonite and zeolite in different percentages for the stabilizing of nutrients and heavy metals in earthen pond sediments for interrupt their release to the water. The pH and electrical conductivity (EC), NH4-N, NO3-N, PO4-P and heavy metals (Cd, Cu, Fe, Mn, Ni, Pb and Zn) in the sediments were measured by 45-day laboratory incubation experiments. The results showed that the highest stabilization efficiency of NH4-N, NO3-N, Cd, Cu, Pb and Zn in the sediments was recorded with zeolite capping of 6% of the sediment weight (ZC 6%) by 65.4%, 41.8%, 66.0 %, 63.9 %, 54.2 % and 57.3 %, respectively, while, the highest stabilization efficiency of PO4-P, Fe, Mn and Ni was with bentonite capping of 6% of the sediment weight (BC 6%) by 61.9%, 42.7 %, 57.0 % and 52.6 %, respectively. Therefore, it is recommended to use bentonite or zeolite as capping material for sediment at a rate of 6% at the bottom of the pond can be effective for the control of nutrients and heavy metals when they are increased in earthen pond sediments for interrupt their release into water.