Investigation the Effect of Low-Impact Development Methods of Rainwater Storage Barrels and Infiltration Trenches on Reducing the Peak Discharges of Urban Floods

Today, due to climate change, limited water resources and population growth, the problem of evaporation from water reservoirs has become a global issue. Various methods have been proposed to reduce evaporation from the water surface, which using heavy alcohols hexadecanol and octadecanol as a powder or solution is one of the common methods. Using these alcohols as a solution is more common because they are less displaced by wind and have a more uniform distribution. The emulsions used include hexadecanol, octadecanol and an equal combination of hexadecanol with octadecanol. Class A evaporation pans were used to evaluate the performance of the emulsions made in reducing evaporation from the water surface. In addition to chemical compounds in this study, physical methods such as floating balls and canopy were used. The experimental results showed that the octadecanol emulsion had better performance against water evaporation than other chemical compounds. Comparison of the performance of the emulsions and the physical methods showed that the two methods of canopy and floating balls had better performance than the chemical methods, although the octadecanol emulsion in some cases had similar performance to the physical methods in reducing evaporation from the water surface. The study of the effect of wind speed on the performance of the monolayer showed that at low wind speeds the performance of the monolayer is similar to that of floating balls and canopy, but gradually with increasing wind speed, the performance of the monolayer decreases sharply.