| Evaporation is an important factor about water loss in arid、semi-arid areas. In order to reduce the evaporation of water consumption problems in Xinjiang, the Shihezi Region was selected as the study area, and the trends characteristic of the evaporation in the last 51 years was analyzed, while studied the anti-wave ability of the Polystyrene board on different thicknesses、different densities and different side nets in Daquangou reservoir of Manas River.through a large number of experimental studies,The main result is as follows:(1)The evaporation in Shihezi City showed a decreasing trend From 1964 to 2014. Its climatic tendency is-86.5 mm/10 a that reducing was more significant.The evaporation in Shihezi evaporation began to enter a decreased evaporation stage from the late 1980 s. Seasonal evaporation variation characteristics of Shihezi as follows: the spring, summer, autumn showed a decreased trend, however the winter showed a weak upward trend,in which the most significant decline was summer. 2002 is the mutation year that Shihezi evaporation more to less, wavelet analysis found Shihezi evaporation had about 18 a decadal cycle in the 51 a timescale, on the time scale undergone three high period and three low period. Correlation analysis shows: air temperature, wind speed, vapor pressure is the main factor that affect the region evaporation.(2)The water evaporation of the full covered 20 m2 pool was 415.5 mm and the average evaporation rate reduction was 51%,while the water evaporation was 469 mm,the average evaporation rate reduction was 54.05% in 4-10 month,2014. The water temperature(1cm, 40 cm, 80 cm, 120 cm) of the water body is more uniform in the condition of benzene plate cover, but the vertical water temperature of uncovered evaporation pool is stratified.From the most obvious hierarchical level in July, its surface temperature is higher than the bottom water temperature 2.2 degrees. The stratification phenomenon gradually disappeared with the decrease of temperature after August. The average water temperature of the whole water layer was lower than uncovered 1.2, 1, 1.65, 0.7, 0.45, 0.1 degree respectively.(3)The reduction rates of the evaporation in pond with the covering rates of polystyrene board being respectively 25%, 50%, 75% and 100% are respectively 23.85%, 39.63%, 55.54% and 63.85%. And the water quality testing result shows that the qualities of the water with different covering rates are all good enough for irrigation. The decreasing rates of the total suspended substances and salts content are respectively 67.1% and 17.3%. The covering rates of the reservoirs only for irrigation could come up to 100%, while that combining with cultivation and shipping should be determined according to the practical situations.(4)Through the field experiment, it is found that: under the same density and coverage its anti-wave ability can be improved 2 grades by increasing 2 cm thickness of the benzene plate; The corner was the most easily damaged area of the cover structure of polystyrene board. On the same thickness and the same density,the double sides reinforced nets covering can enhance 1-2 anti-wave ability grades than one-sided coverage.The structural strength of the benzene plate at the corner of the practical application should be paid noticed. The ability of resisting wind and wave can be improved by increasing the thickness of the polystyrene board and the use of double sided overlay and mesh in the plate structure. The thickness of 5cm, the density of 20 kg/m3 polystyrene board covered with water can resist 6 wind in actual laying experiment of reservoir. Annual prevalence of less than 6 wind areas in the use of polystyrene board cover. |
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