Environmental Engineering Formulas for Civil Engineering Exam | Environmental Engineering - Civil Engineering (CE)

 Page 1


  
Water Demand 
  
Fire Demand 
 Rate of fire demand is sometimes treated as a function of population and is 
worked out on the basis of empirical formulas: 
(i) As per GO Fire Demand 
 
(ii) Kuichling’s Formula 
 
 Where, Q = Amount of water required in litres/minute. 
 P = Population in thousand. 
(iii) Freeman Formula 
 
(iv) National Board of Fire Under Writers Formula 
      (a) For a central congested high valued city 
          (i) Where population < 200000 
 
          (ii) where population > 200000 
 Q = 54600 lit/minute for first fire 
 and Q=9100 to 36,400 lit/minute for a second fire. 
      (b) For a residential city. 
           (i) Small or low building, 
 Q=2,200 lit/minutes. 
           (ii) Larger or higher buildings, 
 Q=4500 lit/minute. 
 (v) Buston’s Formula 
 
  
Per Capita Demand (q) 
 
  
Page 2


  
Water Demand 
  
Fire Demand 
 Rate of fire demand is sometimes treated as a function of population and is 
worked out on the basis of empirical formulas: 
(i) As per GO Fire Demand 
 
(ii) Kuichling’s Formula 
 
 Where, Q = Amount of water required in litres/minute. 
 P = Population in thousand. 
(iii) Freeman Formula 
 
(iv) National Board of Fire Under Writers Formula 
      (a) For a central congested high valued city 
          (i) Where population < 200000 
 
          (ii) where population > 200000 
 Q = 54600 lit/minute for first fire 
 and Q=9100 to 36,400 lit/minute for a second fire. 
      (b) For a residential city. 
           (i) Small or low building, 
 Q=2,200 lit/minutes. 
           (ii) Larger or higher buildings, 
 Q=4500 lit/minute. 
 (v) Buston’s Formula 
 
  
Per Capita Demand (q) 
 
  
Assessment of Normal Variation 
(i)   
(ii)   
(iii)   
(iv)   
(v)  
(vi)  
  
Population forecasting Methods 
 
(i) Arithmetic increase method 
 
 Where, 
  Prospective or forecasted population after n decades from the present (i.e., 
last known census) 
  Population at present (i.e., last known census) 
  Number of decades between now & future. 
  Average (arithmetic mean) of population increases in the known decades. 
  
(ii) Geometric Increase Method 
 
 where, 
  Initial population. 
  Future population after ‘n’ decades. 
  Assumed growth rate (%). 
 
Page 3


  
Water Demand 
  
Fire Demand 
 Rate of fire demand is sometimes treated as a function of population and is 
worked out on the basis of empirical formulas: 
(i) As per GO Fire Demand 
 
(ii) Kuichling’s Formula 
 
 Where, Q = Amount of water required in litres/minute. 
 P = Population in thousand. 
(iii) Freeman Formula 
 
(iv) National Board of Fire Under Writers Formula 
      (a) For a central congested high valued city 
          (i) Where population < 200000 
 
          (ii) where population > 200000 
 Q = 54600 lit/minute for first fire 
 and Q=9100 to 36,400 lit/minute for a second fire. 
      (b) For a residential city. 
           (i) Small or low building, 
 Q=2,200 lit/minutes. 
           (ii) Larger or higher buildings, 
 Q=4500 lit/minute. 
 (v) Buston’s Formula 
 
  
Per Capita Demand (q) 
 
  
Assessment of Normal Variation 
(i)   
(ii)   
(iii)   
(iv)   
(v)  
(vi)  
  
Population forecasting Methods 
 
(i) Arithmetic increase method 
 
 Where, 
  Prospective or forecasted population after n decades from the present (i.e., 
last known census) 
  Population at present (i.e., last known census) 
  Number of decades between now & future. 
  Average (arithmetic mean) of population increases in the known decades. 
  
(ii) Geometric Increase Method 
 
 where, 
  Initial population. 
  Future population after ‘n’ decades. 
  Assumed growth rate (%). 
 
 where, 
  Final known population 
  Initial known population 
  Number of decades (period) between  and   
   
  
(iii) Incremental Increases Method 
 
 Where, 
  Average increase of population of known decades 
  Average of incremental increases of the known decades. 
  
(iv) Decreasing rate of growth method 
 Since the rate of increase in population goes on reducing, as the cities reach 
towards saturation, a method which makes use of the decrease in the percentage 
increase, in many a times used, and gives quite rational results. In this method, the 
average decrease in the percentage increase is worked out, and is then subtraced 
from the latest percentage increase for each successive decade. This method is 
however, applicable only in cases, where the rate of growth shows a downward 
trend. 
  
(v) Logistic Curve Method 
(a)  
 Where, 
  Population of the start point. 
  Saturation population 
  Population at any time t from the origin. 
  Constant. 
  
  
Development of Ground Water 
Page 4


  
Water Demand 
  
Fire Demand 
 Rate of fire demand is sometimes treated as a function of population and is 
worked out on the basis of empirical formulas: 
(i) As per GO Fire Demand 
 
(ii) Kuichling’s Formula 
 
 Where, Q = Amount of water required in litres/minute. 
 P = Population in thousand. 
(iii) Freeman Formula 
 
(iv) National Board of Fire Under Writers Formula 
      (a) For a central congested high valued city 
          (i) Where population < 200000 
 
          (ii) where population > 200000 
 Q = 54600 lit/minute for first fire 
 and Q=9100 to 36,400 lit/minute for a second fire. 
      (b) For a residential city. 
           (i) Small or low building, 
 Q=2,200 lit/minutes. 
           (ii) Larger or higher buildings, 
 Q=4500 lit/minute. 
 (v) Buston’s Formula 
 
  
Per Capita Demand (q) 
 
  
Assessment of Normal Variation 
(i)   
(ii)   
(iii)   
(iv)   
(v)  
(vi)  
  
Population forecasting Methods 
 
(i) Arithmetic increase method 
 
 Where, 
  Prospective or forecasted population after n decades from the present (i.e., 
last known census) 
  Population at present (i.e., last known census) 
  Number of decades between now & future. 
  Average (arithmetic mean) of population increases in the known decades. 
  
(ii) Geometric Increase Method 
 
 where, 
  Initial population. 
  Future population after ‘n’ decades. 
  Assumed growth rate (%). 
 
 where, 
  Final known population 
  Initial known population 
  Number of decades (period) between  and   
   
  
(iii) Incremental Increases Method 
 
 Where, 
  Average increase of population of known decades 
  Average of incremental increases of the known decades. 
  
(iv) Decreasing rate of growth method 
 Since the rate of increase in population goes on reducing, as the cities reach 
towards saturation, a method which makes use of the decrease in the percentage 
increase, in many a times used, and gives quite rational results. In this method, the 
average decrease in the percentage increase is worked out, and is then subtraced 
from the latest percentage increase for each successive decade. This method is 
however, applicable only in cases, where the rate of growth shows a downward 
trend. 
  
(v) Logistic Curve Method 
(a)  
 Where, 
  Population of the start point. 
  Saturation population 
  Population at any time t from the origin. 
  Constant. 
  
  
Development of Ground Water 
 
Darcy Law’s 
 (i)  (For Laminar flow) 
 Where, 
 Q = Discharge 
 k = Coefficient of permeability 
 i = Hydraulic gradient   
 A = Area of flow. 
 (ii)   
 Where, V = Discharge velocity 
 (iii)   
 Where,  Seepage velocity 
  Porosity. 
 (iv)   
 Where, 
  Constant having value 400. 
  Hydraulic gradient 
  Effective size of soil particle 
  Dynamic viscosity. 
 (v)   
 Where, 
  Shape factor (which is a function of porosity), packing and grain size 
distribution). 
  Average size of particle. 
  Kinematic viscosity. 
 
 
Specific yield 
   
Page 5


  
Water Demand 
  
Fire Demand 
 Rate of fire demand is sometimes treated as a function of population and is 
worked out on the basis of empirical formulas: 
(i) As per GO Fire Demand 
 
(ii) Kuichling’s Formula 
 
 Where, Q = Amount of water required in litres/minute. 
 P = Population in thousand. 
(iii) Freeman Formula 
 
(iv) National Board of Fire Under Writers Formula 
      (a) For a central congested high valued city 
          (i) Where population < 200000 
 
          (ii) where population > 200000 
 Q = 54600 lit/minute for first fire 
 and Q=9100 to 36,400 lit/minute for a second fire. 
      (b) For a residential city. 
           (i) Small or low building, 
 Q=2,200 lit/minutes. 
           (ii) Larger or higher buildings, 
 Q=4500 lit/minute. 
 (v) Buston’s Formula 
 
  
Per Capita Demand (q) 
 
  
Assessment of Normal Variation 
(i)   
(ii)   
(iii)   
(iv)   
(v)  
(vi)  
  
Population forecasting Methods 
 
(i) Arithmetic increase method 
 
 Where, 
  Prospective or forecasted population after n decades from the present (i.e., 
last known census) 
  Population at present (i.e., last known census) 
  Number of decades between now & future. 
  Average (arithmetic mean) of population increases in the known decades. 
  
(ii) Geometric Increase Method 
 
 where, 
  Initial population. 
  Future population after ‘n’ decades. 
  Assumed growth rate (%). 
 
 where, 
  Final known population 
  Initial known population 
  Number of decades (period) between  and   
   
  
(iii) Incremental Increases Method 
 
 Where, 
  Average increase of population of known decades 
  Average of incremental increases of the known decades. 
  
(iv) Decreasing rate of growth method 
 Since the rate of increase in population goes on reducing, as the cities reach 
towards saturation, a method which makes use of the decrease in the percentage 
increase, in many a times used, and gives quite rational results. In this method, the 
average decrease in the percentage increase is worked out, and is then subtraced 
from the latest percentage increase for each successive decade. This method is 
however, applicable only in cases, where the rate of growth shows a downward 
trend. 
  
(v) Logistic Curve Method 
(a)  
 Where, 
  Population of the start point. 
  Saturation population 
  Population at any time t from the origin. 
  Constant. 
  
  
Development of Ground Water 
 
Darcy Law’s 
 (i)  (For Laminar flow) 
 Where, 
 Q = Discharge 
 k = Coefficient of permeability 
 i = Hydraulic gradient   
 A = Area of flow. 
 (ii)   
 Where, V = Discharge velocity 
 (iii)   
 Where,  Seepage velocity 
  Porosity. 
 (iv)   
 Where, 
  Constant having value 400. 
  Hydraulic gradient 
  Effective size of soil particle 
  Dynamic viscosity. 
 (v)   
 Where, 
  Shape factor (which is a function of porosity), packing and grain size 
distribution). 
  Average size of particle. 
  Kinematic viscosity. 
 
 
Specific yield 
   
 Where,  Specific yield. 
 Volume of water yielded under gravity effect. 
 Total volume of water drained. 
Specific retention 
   
 Where,  Specific retention. 
 Volume of water retain under gravity effect. 
 Total volume of water. 
  
Where,  Porosity. 
Slot Opening 
Slot size  of D10 of gravel pack material. 
Slot size  of aquifer design on the basis of finest aquifer.  
Well Losses 
Jacob-equilibrium formula for confined aquifer, 
 
Where, 
 Drawdown in observation well after time t. 
 Radial distance of observation well from main pump well. 
 Coefficient of transmissibility = k.d 
 Coefficient of storage. 
 
 Drawdown of observation well at time   
 Drawdown of observation well at time   
    Where,  and  is the distance of drawdown in 
time  and  respectively. 
  
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