SECTION 9 



RECOMMENDED DESIGN AND BEST MANAGEMENT PRACTICES 



Introduction 



Many factors affect the evaporation and precipitation rate in evaporation ponds. As 

 some of these factors are not readily changeable, evaluation of each factor's manageability (or the 

 degree to which the factor can be controlled) to accelerate evaporation and precipitation is 

 addressed. Although evaporation and precipitation are inter-related, they are evaluated 

 separately in finding manageablility factors. These factors will eventually be combined when 

 recommending the design and best management practices for evaporation ponds. 



Factors Which Affect the Evaporation Rate 



Table 9.1 shows factors which affect the evaporation and those factors which are 

 manageable to increase the evaporation rate. Net radiation, salinity and color of effluents can 

 be controlled by specifying design and management practices. 



Table 9.1 Evaporation rat« factors and manageability 



EVAPORATION RATE FACTORS MANAGEABLE FACTORS 



O Climatic property O Climatic property 



Net Radiation Net Radiation 



Humidity 

 Air Temperature 

 Wind Velocity and Direction 



C Water Property <" Water Property 



Salinity Salinity 



Color Color 



Temperature 

 Chemical Composition 

 Turbidit>' 



Net Radiation . 



Net radiation is defined as the difference between the amount of solar radiation which 

 reaches the earth's surface, and the amount of refiect^d and reradiated radiation. Evaporation 

 rate is calculated using the energy balance and Bowen ratio; 



E = ^^ (1) 



Ul + B) 



E = evaporation 



R = net radiation 



S = heat stored in water 



L = latent heat of water vaporization 



B = Bowen ratio 



page 9.1 



