EVAPORATION SUPPRESSION FROM WATER SURFACES USING CHEMICAL FILMS by iaemedu

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									   International Journal of Civil Engineering and CIVIL ENGINEERING AND
   INTERNATIONAL JOURNAL OF Technology (IJCIET), ISSN 0976 – 6308
   (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 3, May - June (2013), © IAEME
                             TECHNOLOGY (IJCIET)

ISSN 0976 – 6308 (Print)
ISSN 0976 – 6316(Online)                                                      IJCIET
Volume 4, Issue 3, May - June (2013), pp. 185-196
© IAEME: www.iaeme.com/ijciet.asp
Journal Impact Factor (2013): 5.3277 (Calculated by GISI)                  © IAEME
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     EVAPORATION SUPPRESSION FROM WATER SURFACES USING
                      CHEMICAL FILMS

                        Dr. Umesh J. Kahalekar1, Hastimal S. Kumawat2
       1
         (Professor and Head- Dept. of Civil Engineering, Government College of Engineering
                                 Aurangabad-431005 (M.S.), India)
     2
       (Post Graduate Student- Government College of Engineering Aurangabad-431005 (M.S.),
                                               India)


   ABSTRACT

           The extremely high rate of Evaporation from water surfaces day by day is reducing
   the optimal utilization of water reservoirs. The work presented in this study aims to investing
   the use of Chemical films as Evapo Suppretants for reduction of evaporation from the open
   water surface so as to increase the storage efficiency. Particular emphasis will be on practical
   procedures and techniques that professionals can use to estimate and/or to suppress
   evaporation from shallow water bodies. The natural evaporation loss taking place from pan
   evaporimeters of two alcohols were observed and compared. The important meteorological
   factors affecting the natural evaporation such as Temperature, Relative Humidity, Wind
   Velocity, Sunshine Hours, etc. were also observed.
           Cetyl and Stearyl Alcohols were selected to reduce the evaporation during the study
   period in Aurangabad region with two US Class-A evaporation pans. Different concentrations
   of Cetyl and Stearyl alcohols were used in different pans. First pan EP1 was filled with water
   without adding chemical while in pan EP2 alcohols was added. The preliminary results of the
   study indicated that evaporation rate from surface water was reduced overall upto 28% in pan
   EP2 as compared to pan EP1 while the Cetyl alcohol individually gives the average reduction
   is 27% and the Stearyl alcohol gives 27% and Both Cetyl and Stearyl Alcohol combine gives
   the average reduction is 30%. The Penman’s Equation is used to compare the evaporation
   values in evaporation pan 1.

   Keywords: Cetyl & Stearyl Alcohols, Class-A Pan, Evaporation Reduction, Evaporation
   Suppression, Penman’s equation



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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
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1.     INTRODUCTION

         Water is one of the nature’s precious gifts, which sustains life on earth. Civilizations
over the world have prospered or perished depending upon the availability of this vital
resource. Water has been worshiped for life nourishing properties in all the scriptures. Vedas
have unequivocally eulogized water in all its virtuous properties.
         The total water resources on earth are estimated to be around 1360 Million cubic km.
Out of which only about (33.5 Million cubic km) is fresh water. India possesses only 4% of
total average runoff of the rivers of the world although it sustains 16% of the world’s
population. The per capita availability of water in the country is only 1820 m3/year, compared
to 40855 m3/year in Brazil, 8902 m3/year in USA, 2215 m3/year in China, 2808 m3/year in
Spain, 18162 m3/year in Australia, 3351 m3/year in France, 3614 m3/year in Mexico and 3393
m3/year in Japan. The total water resources of India are estimated to be around 1,869 Billion
cubic meters. Due to topographic, hydrological and other constraints, only about 690 BCM of
total surface water is considered as utilizable [1].
         Due to high temperatures and arid conditions in about one third of the country, the
evaporation losses have been found to be substantial. Therefore, it is imperative to minimise
evaporation losses in the storages/water bodies.
         Evaporation losses from on-farm storage can potentially be large, particularly in
irrigation areas in where up to 40% of storage volume can be lost each year to evaporation.
Reducing evaporation from water storage would allow additional crop production, water
trading or water for the environment. The need for prevention of enormous evaporation losses
assumes greater significance, in view of the predictable scarcity of water; the country will be
facing in future. It has been assessed that against the utilizable water resources of the order of
1123 BCM, the requirement by 2025 AD to be met from surface water resources will be
around 1093 BCM, thereby surplus by just 30 BCM[1, 2].
         Due to intense agricultural practices, rapid increase in population, industrialization
and urbanization etc., scarcity of water is being increasingly felt. In the present scenario of
utmost strain on the water resources, of the country, it becomes necessary to conserve water
by reducing evaporation losses. National Water Policy-2002 under Para 19.1 emphasises that
evaporation losses should be minimised in drought-prone areas [1].
         The internet was also browsed to search the information on any new researches or
identification of any new technology / chemicals to retard the evaporation rate. The search on
internet, resulted in finding some case studies done in this field in other countries, however,
the chemicals / technology used is the same. Some websites are from the manufacturers of
WER chemicals such as Hexadecanol or Octadecanol or Acilol claiming to have conducted
experiments in other countries towards evaporation control [3, 4, 5].
         Chemical substances such as Cetyl and Stearyl alcohols can be sprayed periodically
on water surface to reduce evaporation. After a detailed review of the available evaporation
reduction methods, surface water cover technique was selected using Cetyl and Stearyl
alcohol emulsion substances to form a thin monomolecular film over water surface to reduce
evaporation [6]. This method has several advantages over other methods. It is economically
feasible due to low cost of substances and easily available. It mixes with water easily and
when added to large water surface; it forms a thin invisible film that reduces evaporation
considerably. It decomposes easily and doesn't dissolve in water.
         There are several methods to measure evaporation from free water surfaces through
(US weather class-A pan), or more accurately by using energy balance equations. Due to
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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 3, May - June (2013), © IAEME

several factors including air movement and fluctuations of water surface, which affect the
accuracy of measurement of evaporation depth therefore, standard and well recognized
method of (US weather class-A pan) was selected for the present study [7].
        The present study was conducted to measure the reduction of evaporation on
relatively small and controlled water surface of two pans (US weather class-A pan) with
continuous measurement of air temperature, relative humidity, wind velocity and evaporation
rates and evaluated the results in terms of efficiency in reducing evaporation. The evaporation
pan 2 was added with Cetyl and Stearyl alcohols as thin film on water surface to reduce
evaporation. Based on material safety data sheet, the substance does not have any harmful
effects on human beings, animals or plants however; further study is required to determine
the potential environmental, health and ecological impacts of the substance on aquatic
animals and plants [8,9,10].

2.       MATERIALS AND METHODOLOGY

        The study was conducted at Aurangabad (Marathwada region of M.S.) with the help
of a fully operated meteorological station with sensors to measure sunshine hours, air
temperature, wind velocity and relative humidity. Two US weather class-A pans were used
with an accurate measuring tool to measure daily water depth in the pans. A protection cover
was constructed to protect the pans from birds and other animals.
        The amount of chemical films (Cetyl and Stearyl alcohols) added to the two
evaporation pans was calculated and applied to one of the pan for fifteen days duration. No
chemical was added to pan (EP1) to measure natural evaporation rate due to ambient
conditions and for comparison. In pan (EP2), 50 mg per m2 of water surface per day, to make
the effective substance in pan (EP2) is 58.35mg/day and as that of 100mg and 150 mg is
calculated.
        A monolayer is formed on a water surface when long-chained alcohols such as Cetyl
alcohol (Hexadecanol) are spread across the water. The chemical spreads spontaneously
across the surface resulting in a layer only one molecule thick (about two millionths of a
millimetre). The molecules of the monolayer ‘stand’ on the surface because they are
amphiphilic i.e. they have a soluble end and an opposing insoluble end (Fig.1).




     Figure 1 Monolayer molecules ‘standing’ on the water surface (courtesy Geoff Barnes,
                                University of Queensland)

       Duration the entire study period (Jan-Sept 2012), Cetyl and Stearyl Alcohols was
sprayed daily in evaporation pan EP2 and meteorological parameters including air
temperature, relative humidity, wind speed and sunshine hours as well as water levels in two

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pans were measured. The standard procedure was strictly followed and maintained during
measurements of the readings for accuracy and consistency of the results throughout the
duration of the study. All the pans were cleaned regularly to remove sediments from pans, if
any.

3.     RESULTS AND DISCUSSION

       The results of the study indicated that air temperature ranges from 15.0-41.0°C with
average of 34.5°C, while wind velocity ranges from 0.4-12 km/hr with average of 3.9 km/hr.
The relative humidity ranges from 25-95% with average of 66.8%. Similarly, the daily pan
evaporation rates ranges from 1-9.7 mm/day with average of 6.4 mm/day. The pan
evaporation rate reached its peak in June and it reached 9.7 mm/day.

 Table1. Summary of the experiment results of the daily reduction of pan evaporation rates
                                for different months

                                 Evaporation Evaporation              %
                 Duration
                                 mm/day (EP1) mm/day (EP2)         Reduction

            16 Jan -31 Jan            5.41             4.16          23.13
            01 Feb - 29 Feb           5.72             4.36          23.97
            01 Mar -31 Mar            6.15             4.40          28.37
            01 Apr - 30 Apr           7.55             5.26          30.29
            01 May - 31 May           8.15             5.14          36.93
            01 June - 21 June         7.11             5.40          23.76
            22 Aug - 31 Aug           3.68             2.68          25.69
            01 Sept -12 Sept          3.89             2.76          28.01
                       Average        5.96             4.27          27.52


     Table 2. Summary of the experiment results - chemical wise reduction in percentage
       Reduction using only     Reduction using only        Reduction using cetyl +
            cetyl alcohol           stearyl alcohol              stearyl alcohol
                23.13                    22.66                        25.28
                27.07                    26.73                        29.67
                33.85                    31.98                        41.88
                21.06                    24.48                        25.73
                26.17                    28.01                        25.21
      Average                   Average                   Average
                    26.26%                    26.77%                       29.55%
      Reduction                 Reduction                 Reduction

       Table 1 shows the daily average evaporation rate for 8 months from January to
September. In table 2 the chemical wise reduction is shown. The average reduction recorded
using only Cetyl alcohol is about 26.26%. The average reduction recorded using only Stearyl
alcohol is about 26.77%. The average reduction recorded using Cetyl and Stearyl alcohol is
about 29.55%.

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       Chemical and concentration wise reduction in percentage is shown in table 3.It is
cleared from this table as the concentration is increased the reduction is also increased while
the cetyl and stearyl alcohols combine perform better than other two concentrations and
chemicals. In table 4 the reduction in percent concentration wise is shown.

 Table 3. Summary of the experiment results - chemical and concentration wise reduction in
                                       percentage
                          Reduction using only cetyl alcohol
           23.13      for       27.07          for         --          for
           21.06 50mg/m2/day 26.17 100mg/m2/day 33.85 150mg/m2/day
           22.09 Average        26.62 Average            33.85 Average
                         Reduction using only stearyl alcohol
           22.66     for       26.73        for          --       for
           24.48 50mg/m2/day 28.01 100mg/m2/day 31.98 150mg/m2/day
           23.57 Average       27.37 Average           31.98 Average
                       Reduction using cetyl + stearyl alcohol
           25.28     for      29.67        for           --       for
           25.73 50mg/m2/day 25.21 100mg/m2/day 41.88 150mg/m2/day
           25.51 Average      27.44 Average            41.88 Average

  Table 4. Summary of the experiment results - concentration wise reduction in percentage
             for 50mg/m2/day      for 100mg/m2/day         for 150mg/m2/day
                    23.13                27.07                   33.85
                    25.28                29.67                   41.88
                    22.66                26.73                   31.98
                    21.06                26.17                      --
                    24.48                25.21                      --
                    25.73                28.01                      --
                 Avg. 23.72            Avg. 27.14              Avg. 35.90
            Difference Between 50mg/m2/day and 100mg/m2/day: 3.42
            Difference Between 100mg/m2/day and 150mg/m2/day: 8.76

       The daily average pan evaporation rate for 4 summer months (March, April, May and
June) was measured as 6.15, 7.55, 8.15 and 7.11 mm/day, respectively. Thus, middle four
months (March to June) witnessed the highest evaporation rates due to high temperature and
low humidity.
       The readings are validated with help of Penman’s equation for evaporation [11], the
following equation were used.

           Qn ∆            
           L + 0.00061P.Ea 
        E= e                                                                            (1)
               ( ∆ + 0.00061P )
where,
Qnis the net solar radiation used in evaporation in cal/sq.cm

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       Qn= Qi (1– r) – Qb                                                                (2)

Qi is the incoming solar radiation

                                  n
                                                                                         (3)
        Qi = Q0  a + 0.55          
                                  N

Q0 is the radiation in cal/cm2/dayreceived at the top of the atmosphere

       a = 0.29 cosθ                                                                     (4)

θ is the latitude of the place
nis the actual number of sunshine hours in the day,
N is the maximum possible hours of bright sunshine
ris called the reflection coefficient or the albedo whose value may be taken as 0.05 for water
surface
Qbis the net outgoing longwave radiation


                       (                )
        Qb = σ T 4 0.56 − 0.09 ea  0.1 + 0.9
                                         
                                                n
                                                 
                                                N
                                                                                         (5)


σ is the Stefan-Boltzman constant
        σ = 118.944 x 10-9 cal/cm2/day/°K                                                (6)

T is the mean daily temperature in °K
eais the actual vapour pressure of air in mm of mercury
               100es
        ea =                                                                             (7)
                R.H .

R. H. is the Relative Humidity in %
∆ is the slope of saturation vapour pressure curve at air temperature t in mb/°C
                 4098es
        ∆=                     2
                                                                                         (8)
               ( 237.3 + t )

esis the saturated vapour pressure corresponding to the mean daily air temperature
                       17.27T 
         es = 6.11exp                                                                  (9)
                       237.3 + T 

t is the air temperature in °C
Le is the latent heat of vaporization of water in cal/g which varies with the temperature and
can be obtained from

        Le = 597.3 – 0.564 t                                                           (10)
P is the atmospheric pressure in kPa

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                                                                                                                         5.26
                                                   293 − 0.0065 z 
                                        P = 101.3                                                                                                                                                                                                                                   (11)
                                                        293       

z is the elevation above sea level in m
Eais the evaporation from the water surface when water and air temperatures are equal

                                    Ea= 0.35(0.5 + 0.54 V) (es - ea)                                                                                                                                                                                                                  (12)

V is in m/s measured at a height of 2 m above the free surface
        The regression model is shown in Fig. 2 is drawn for the study period 16 January to
21 June. The data is best fitting by the regression analysis. The best fit for EP1got from model
is 45.94%. The best fit for using Penman’s equation got from model is about 46.1% and that
of EP2the best fit get from model is about 32.52%. These regression models are showing the
linearity of recorded data and Penman’s equation data.
        The regression model shown in Fig. 3 indicates the study period between 16 Jan to 12
Sept. firstly it decided to check the efficiency of cetyl and Stearyl alcohols in summer
therefore the reading were taken for the period 16 Jan to 21 June. Whatever readings were not
available in the graph that is due to evaporation reading and other data are not recorded for
period 22 June to 21 Aug. the reading and other data were continues after this gap and
respective regression model is drawn for remaining period upto 12 Sept.

            10.8
                                                                                                                                                                                                                                                                           y = 0.026x - 1078.
                                                                                                                                                                                                                                                                               R² = 0.461
            10.0


                       9.2


                       8.4
  Evaporation mm/day




                       7.6


                       6.8
                                                                                                                                                                                      y = 0.019x - 780.3
                                                                                                                                                                                          R² = 0.459
                       6.0


                       5.2


                       4.4
                                                                                                                                                                                                                                  y = 0.01x - 406.1
                                                                                                                                                                                                                                     R² = 0.325
                       3.6


                       2.8
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                                                                                                                                                              Days
                                                                Evaporation mm/day (EP1)                                                                                                                     Evaporation mm/day (EP2)
                                                                Evaporation Using Penman's Eqn                                                                                                               Linear (Evaporation mm/day (EP1))
                                                                Linear (Evaporation mm/day (EP2))                                                                                                            Linear (Evaporation Using Penman's Eqn)


  Figure 2. Linear regression model showing EP1, EP2 and evaporation using Penman's eqn
                              (depth in mm) {16 Jan -21 June}

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              11.0


              10.2


                       9.4


                       8.6
                                                                                                                                                                                                                                                                                                                  y = 0.004x - 175.9
                                                                                                                                                                                                                                                                                                                      R² = 0.026
                       7.8
  Evaporation mm/day




                       7.0
                                                                                                                                                                                                                                                                                                      y = -0.003x + 137.4
                                                                                                                                                                                                                                                                                                           R² = 0.017
                       6.2


                       5.4


                       4.6


                       3.8
                                                                                                                                                                                                                                                                                                         y = -0.003x + 151.1
                                                                                                                                                                                                                                                                                                              R² = 0.050
                       3.0


                       2.2


                       1.4
                             16/01/12
                                         23/01/12
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                                                                                                                                                                                                              Days

                                        Evaporation mm/day (EP1)                                                                                                             Evaporation mm/day (EP2)                                                                                                               Evaporation Using Penman's Eqn
                                        Linear (Evaporation mm/day (EP1))                                                                                                    Linear (Evaporation mm/day (EP2))                                                                                                      Linear (Evaporation Using Penman's Eqn)



   Figure 3. Linear regression model showing EP1, EP2 and evaporation using Penman's eqn
                               (depth in mm) {16 Jan -12 Sept}


        After these observed data the respective regression models is plotted. From this model
it is observed that the model is not fitting to that extent. So, from all these studies it is
concluded that the films are not that much efficient in rainy season as that of in summer
season.
        It is observed that splashing or overflowing of the pan may cause the flowing of
chemical film with it. The high wind velocity breaks or may breaks therefore no layer is form
and therefore water gets evaporated. Again the rain droplets may reduce the efficiency of the
chemical films.
        The relationship of air temperature, wind velocities and relative humidity with the
evaporation was determined with the help of linear regression analysis of daily observed data.
A linear regression model for best fit of observed data for daily air temperature and daily
evaporation depth in mm for both pans (EP1and EP2) was developed as in Fig. 4.




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                             12.0



                             10.0



                              8.0
                                                                                                               y = 0.258x - 2.491
                                                                                                                   R² = 0.556
        Evaporation mm/day




                              6.0



                              4.0
                                                                                                                                             y = 0.144x - 0.420
                                                                                                                                                 R² = 0.412
                              2.0



                              0.0
                                    0.0       5.0          10.0           15.0        20.0         25.0              30.0             35.0           40.0         45.0
                                                                                       Temperature °C
                                               Evaporation mm/day (EP1)                                             Evaporation mm/day (EP2)
                                               Linear (Evaporation mm/day (EP1))                                    Linear (Evaporation mm/day (EP2))


                                     Figure 4.Linear regression model for daily air temperature and daily evaporation
                                                                   {16 Jan- 12 Sept}

        The model indicated that there is a direct correlation between air temperatures with
the daily pan evaporation rates. Similarly, a linear regression model for best fit of observed
data for wind velocity and daily evaporation depth (mm) was developed as in Fig. 5.

                        12.0



                        10.0



                             8.0
 Evaporation mm/day




                             6.0
                                                                                                                                        y = -0.296x + 7.565
                                                                                                                                             R² = 0.179
                             4.0



                             2.0
                                                                                                                            y = -0.207x + 5.356
                                                                                                                                 R² = 0.207
                             0.0
                                    0.0             2.0             4.0             6.0                  8.0                  10.0                12.0             14.0
                                                                                   Wind Velocity km/hr

                                             Evaporation mm/day (EP1)                                                Evaporation mm/day (EP2)
                                             Linear (Evaporation mm/day (EP1))                                       Linear (Evaporation mm/day (EP2))



                                      Figure 5.Linear regression model for daily wind velocity and daily evaporation
                                                                   {16 Jan- 12 Sept}

        The model indicated that there is a direct correlation between wind velocities with the
daily pan evaporation rates. In addition, a simple regression model for best fit of observed
data for daily relative humidity and daily evaporation depth (mm) was developed as in Fig. 6.

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                             12.0



                             10.0
                                                                                y = -0.036x + 8.836
                                                                                     R² = 0.131
                              8.0
 Evaporation mm/day




                              6.0
                                                  y = -0.024x + 6.197
                                                       R² = 0.144
                              4.0



                              2.0



                              0.0
                                    0.0           10.0         20.0             30.0         40.0             50.0        60.0           70.0        80.0           90.0        100.0
                                                                                             Relative Humidity %
                                                   Evaporation mm/day (EP1)                                                        Evaporation mm/day (EP2)
                                                   Linear (Evaporation mm/day (EP1))                                               Linear (Evaporation mm/day (EP2))



                               Figure 6.Linear regression model for daily relative humidity and daily evaporation
                                        Linear                                     humidity
                                                             {16 Jan- 12 Sept}

        The model indicated that pan evaporation rates decreases as humidity increases and
that there is an inverse correlation between average daily relative humidity with the daily pan
evaporation rates. The results of the pan evaporation control experiment after adding
chemical film solution with different concentrations and without application in two different
evaporation pans from January to September is presented in Fig. 7.

                               92.0

                               84.0

                               76.0

                               68.0

                               60.0
            Evaporation mm




                               52.0

                               44.0

                               36.0

                               28.0

                               20.0

                               12.0

                                4.0
                                          16-31    01-15   16-29        01-16     17
                                                                                  17-31   01-15       16-30     01-16   17-31    01-07     08-14   15-21       28
                                                                                                                                                            22-28    29 Aug-   05-12
                                           Jan      Feb     Feb          Mar       Mar     Apr         Apr      May     May       June      June    June     Aug      4 Sept    Sept
                                                                                                        Months
                                                                                Evaporation mm/day (EP1)                Evaporation mm/day (EP2)

          Figure 7.Cumulative daily evaporation depth (mm) measured for two pans (EP1 and EP2)
                   Cumulative
                                           {16 Jan - 12 Sept}

        Similarly daily average gross evaporation rates for different months for two pans were
compared and the evaporation reductions in percentage were calculated. Table 1 show that
                ily
the average daily average gross evaporation rates and percentage of reduction of evaporation
rate for different months for two pans.

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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 3, May - June (2013), © IAEME

        The pan evaporation rates are smaller in winter as compared to the summer months.
In general, evaporation rate from pan EP1 is reduced by 27.52% as compared to pan EP2
when the recommended concentration was applied. Similarly, in table 4 the reduction in
percent concentration wise. The concentration where used as per recommendations it is
observed that 23.72 % reduction is achieved. If this quantity is doubled i.e. 100mg then 27.14
% average reduction is possible. If this quantity is tripled then the results are tremendously
increased i.e. about 35.90 % reduction is possible.
        These findings confirmed that there is a significant reduction in evaporation from free
water surfaces when we applied the chemical films i.e. Cetyl and Stearyl alcohols and it is
highly feasible and cost effective to use the substance to reduce evaporation.

                  8.4

                  7.8

                  7.2

                  6.6

                  6.0
 Evaporation mm




                  5.4

                  4.8

                  4.2

                  3.6

                  3.0

                  2.4
                         16-31   01-15   16-29   01-16     17
                                                           17-31    01-15   16-30    01-16   17-31   01-07    08-14   15-21      28
                                                                                                                              22-28   29 Aug-   05-12
                          Jan     Feb     Feb     Mar       Mar      Apr     Apr      May     May     June     June    June    Aug     4 Sept    Sept
                                                                                    Months

                                                         Evaporation mm/day (EP1)              Evaporation mm/day (EP2)

                                 Figure 5.Monthly evaporation depth in mm {16 Jan - 12 Sept}
                                          Monthly

4.                      CONCLUSION

        As the duration of rainy season and quantity of rainfall is reduced, the demand of
water is day by day increasing due to increase in population and Industrialization therefore,
                                                                               st
the economic value also increases. Therefore the government should adopt the strategic plans
for storage and maximum utilization of rainwater. Protecting the stored water in water bodies
                                 .)
(Dams, Reservoirs, Lakes, etc.) from evaporation remains an integral part of sustainable
planning, especially during the summer hot months, when temperature is high and humidity
is low, which leads to extremely high rate evaporation from water surfaces. Chemical films
                  d
such as Cetyl and Stearyl alcohols are one of most feasible and cost effective evaporation
retardants which reduces evaporation significantly. The present study has confirmed that a
chemical film produces an invisible thin monomolecular film over water surface that
      icantly
significantly reduces evaporation. The experimental study was conducted to demonstrate the
                            n                          class A
effectiveness of evaporation reduction on US weather class-A pans adding chemical films of
                                                  2
different concentrations of 50, 100 and 150 mg/m /day. The study concluded that evaporation
was reduced up to 28% as compared to without addition of chemical films. Therefore, these
chemicals are highly feasible and cost effective to apply the present evaporation reduction
technique on a large scale to a large number of reservoirs of the Marathwada region to reduce
the water loss through evaporation from water surfaces.

                                                                               195
International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 3, May - June (2013), © IAEME

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