2 results
Now showing1 - 2 of 2
- Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Seasonal Variation of Evaporation Suppression Efficiency in Water Reservoirs Covered with Floating Elements(2024-12-12); ; ; ; Since the dawn of civilization water reservoirs have been used to support irrigation and livestock in many arid regions of the world [1]. Evaporative losses diminish reservoir storage efficiency; hence, different means such as floating covers have been proposed to reduce losses. While laboratory and field studies have evaluated effects of cover properties (e.g., geometry, thermal, and radiative characteristics) on Evaporation Suppression Efficiency (ESE) [2-4], the influence of seasonal climate variability on ESE remains understudied. We conducted long-term field measurements in two identical water reservoirs (area: 25 m2, depth: 2 m) in a dry region to investigate how seasonal variations in atmospheric conditions affect ESE. We compared the evaporation rate and water temperature profile in a reservoir covered with Styrofoam discs (D: 50 cm, H: 5 cm) with those in an uncovered reservoir. For 90% surface coverage, measurements indicate that ESE varied from nearly 80% in summer to about 60% in winter. Temperature variations and radiative energy storage within the reservoirs show that the opaque and thermal insulating characteristics of the Styrofoam discs and their effects on wind-induced mixing lead to thermal stratification and formation of a seasonal thermocline in the covered reservoir. These affect the exchange of accumulated summer heat with overlying air resulting in a slower reduction in evaporation rate compared to the uncovered reservoir in cold seasons. The study sheds new light on thermal regimes and ESE in partially covered multiuse reservoirs under different climatic conditions.Publicationtype: Conference Poster27 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Effects of floating covers used for evaporation suppression on reservoir physical, chemical and biological water quality parameters(Wiley, 2022-08-21); ; ; ; Increasing demand for freshwater in arid regions with chronic water shortage calls for expansion of water storage for drought periods while protecting storage from evaporative losses. A cost-effective and scalable method for evaporation suppression uses floating elements; however, little is known regarding biochemical and water quality effects under these covers. Two identical reservoirs with area of 25 m2 and depth of 2 m were used to investigate the influence of floating covers on water quality parameters for a period of one year (2019–2020). One of the reservoirs was covered with Styrofoam discs, and results were compared with the uncovered one. Results showed that the evaporation suppression efficiency of floating discs gradually decreased from 80% in spring to about 60% in winter. The comparison between reservoirs revealed that the presence of floating covers decreased pH, electrical conductivity (EC), total dissolved solids (TDS) and dissolved oxygen by 11%, 11%, 15% and 36%, respectively. We observed an increase in nitrate (30%), phosphate (27%) and ammonia (95%) concentrations in the covered reservoir. Results also demonstrated more concentration of biological populations such as algae and protozoa in the uncovered reservoir. The findings highlight improvement of certain water quality parameters in covered reservoirs such as EC and TDS with potential impacts on irrigation systems and soil health and salinity constraints.Publicationtype: Journal Article41 1