Expert lecture on " Water Demand For Drinking and Agriculture " by Dr.S.Suresh, Civil Engg., Sona College of Technology

1. WATER A LOOMING CRISIS ?
WATER DEMAND FOR DRINKING AND
AGRICULTURE
by
Dr. S. Suresh
Professor, Department of Civil Engineering
Sona College of Technology (Autonomous)
Salem-5

2. CITY OF CHENNAI HAS REACHED A CRISIS POINT
AFTER ITS FOUR MAIN WATER RESERVOIRS RAN
COMPLETELY DRY. 18TH JUNE, 2019- BBC
Empty water pots in Chennai,
which has run out of water

3. POONDI - SATHYAMOORTHY RESERVOIR
Water volume : 3,231 million cubic
feet
Tiruvallur district, Chennai

4. CHEMBARAMBAKKAM LAKE
Chembarambakkam is a lake
located bout 25 km
from Chennai.
Surface area is 3,800 acres
(15 km
2
)
Water Volume is 3,645 million
cubic feet

5. PUZHAL LAKE
(RED HILLS)
Puzhal lake, also known
as the Red Hills Lake, is
located in Red
Hills, Chennai, India. It
lies in Thiruvallur
district of TamilNadu
state.
Surface area: 4,500 acres (18 km
2
)
Water Volume: 3,300 million cubic feet

6. CHOLAVARAM LAKE
Water Volume : 881 million cubic feet
Location : Thiruvallur district, TN, India

7. UNDER STANDING CHENNAI’S ECOSYSTEM

8. BACK DROP
Some 18% of the world’s population resides in India and
they survive on just 4% of the world’s freshwater.
Rapid population growth and urbanization, a growing
agricultural and industrial sector, as well as climate impacts
- mainly drought and flooding - are putting these limited
resources under increasing strain.
Groundwater is at the heart of water crisis. In a recent
assessment from the Central Ground Water Board in
India found that of the 447 billion cubic metres of
groundwater which is replenished each year, some 228
billion cubic metres of this is used for agricultural irrigation.

9. WATER MANAGEMENT IN CHENNAI
The coastal city of Chennai has a metropolitan
population of 10.6 million as per 2019 census.
Water demand of Chennai is projected at 2,248
million litres per day MLD in 2026.
Water supply is estimated at 1,535 MLD.
Chennai is expected to face a huge deficit of 713
MLD.

10. REASONS BEHIND WATER SCARCITY IN INDIA
 The water scarcity is mostly man made due to excess population
growth
 mismanagement of water resources.
 Inefficient use of water for agriculture (Traditional techniques of
irrigation)
 Reduction in traditional water recharging areas (Rapid
construction)
 Lack of on-time de-silting operations which enhance water
storage capacity during monsoon.
The solution :
 Use of micro-irrigation techniques such as drip and sprinkler
irrigation.

12. PRECIPITATION
Precipitation denotes all
forms of water that reach
the earth from the
atmosphere.

13. FORMS OF PRECIPITATION
Common forms of precipitation are
Rain - water drops of size larger than 0.5 mm,
Snow - density varying from 0.06 to 0.15 g/cm3 ,
drizzle - Water Droplet Of Size Less Than 0.5mm,
glaze - Forms an Ice Coating Called Glaze ,
Sleet - frozen raindrops of transparent grains ,
hail - lumps of ice of size more than 8mm.

14. MEASUREMENT OF PRECIPITATION
 Non recording rain gauge
-- Symon’s Rain gauge
 Recording rain gauge
 Tipping Bucket raingauge
 Weighing bucket raingauge
 Float tupe rain gauge 14

16. SYMON’S RAIN GAUGE
A funnel with circular rim 12.7 cm diameter and
glass bottle
Metal casing fixed on masonry foundation
Projection above the ground is 30.5 cm
Measuring glass graduated in millimeter are used to
measure the rainfall
16

18. LOCATION OF RAIN GAUGE
Rain gauge should be located such that it should not
affect to wind effect, interception by tress and
buildings near by. The best location is open plain
ground.
18

19. RAIN GAUGE DENSITY
Areas Rain gauge Density
Plains 1 in 520 km2
Elevated Regions 1 in 260 – 390 km2
Hills and high rainfall
areas
1 in 130 km2
19

20. GRAPHICAL PRESENTATION OF
RAIN FALL DATA
Mass curve of rainfall
The mass curve of rain fall is a plot of the
cumulative depth of rain fall against time.
Hyetograph
A hyetograph is a plot of the intensity of rainfall
against the time interval. The hyetograph is
represented as bar chart.
20

21. AGRICULTURAL ENGINEERING
• As a support to increase agricultural production in
a densely populated country like India, irrigation
facilities need to be strengthened. In Tamilnadu,
tanks are a major sources of water for irrigation. A
total number of 39200 tanks existing in Tamilnadu.
• A majority of the tanks are rain fed tanks
depending mainly on monsoon rainfall. The user
agencies and farmers are not able to plan
effectively the irrigation scheduling and crop
pattern because the rainfall and flow are uncertain
phenomena. 21

22. RESEARCH ON RAINFALL AND FLOW
PREDICTION
• Adaptability of two stochastic prediction models
for two typical tank catchments.
• In one model, Autoregressive approach, the
weekly rainfall or weekly flow is treated as a single
time series.
• In another model, multiple time series Wiener
approach, weekly rainfall and weekly flow is
considered together.
22

23. STUDY AREA
23

24. AUTO PROJECTION OF RAIN
24

25. WEEKLY RAIN PREDICTION BY AUTOREGRESSIVE
SCHEME FOR NORTHEAST MONSOON – 2018,
ARALIKOTTAI TANK
25

26. MULTIPLE TIMES SERIES ANALYSIS – WIENER
APPROACH
26

27. 27

28. 28

29. WIENER APPROACH : WEEKLY FLOW PREDICTION 2018
NORTHEAST MONSOON - ARALIKOTTAI TANK
29

30. Thank You
30