Environmental Engineering Formulas for Civil Engineering Exam

# Environmental Engineering Formulas for Civil Engineering Exam - Notes | Study Environmental Engineering - Civil Engineering (CE)

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``` 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.
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.
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.

Quality control of Water Supplies
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## Environmental Engineering

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## Environmental Engineering

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