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The value of landscaping, how water conservation can be carried out through efficient design, better products & proper installation
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Water Management for Better
Landscapes
Mohan Subramanian
Water and Landscape
Importance of water
Water is found in the landscape as a water
body or a fountain
But the most important water component is
the one you do not see
The water that nourishes the plants is critical
to ensure the landscape is lively and healthy
Providing adequate amount of this water is
the main purpose of Irrigation.
The World’s Water Crisis
There is no new water.
Outlook for the Future
69% of water used in
Agriculture
More efficient use can
have significant impact
on available supply
Increasing number of
international and
regional summits
Working together to
find a solution
The Indian Context
More than 700 million Indians lack access to
sanitation and safe drinking water
More than 2.1 million children under the age
of 5 die due to disease related to water.
22 Million bore-wells pump water whenever
there is power and pump out roughly 200
Cubic Kilometres of water every year
The Value of Landscaping
Beauty and relaxation
for family, employees
and visitors
Increases real estate
market value
Provides safe,
high-quality play
and exercise areas
The Value of Landscaping
Soil erosion control
Rainwater entrapment and
ground water recharge
Provides shelter for
wildlife
Solar heat dissipation
Reduces air and noise
pollution
Conservation Through Efficient Irrigation
Proper system design
Use water-conserving products
Proper system installation
Proper maintenance and usage
Proper Irrigation Design
Different plants require
different amounts of water
Understand exactly what
will be irrigated
Divide by zones
Use the right products for
the right applications
Consult a licensed
professional
Use of Water Conserving Products
Significant recent
advances in irrigation
technology
Automated systems are
more efficient than
hand watering
Can be set to deliver
exactly the amount of
water needed
Automatic Controllers with
Water Conserving Features Multiple start times and
multiple independent programs
Cycle+Soak™
Water budget
ET Programming
Rain Delay
Pump Station Control
Add an Automatic Shut-Off Device
Rain, moisture and wind
sensors automatically
suspend watering
15-20% or more in water
savings
Very simple to install and
maintain. Cost effective
too.
Efficiency
Typical Efficiency Levels:
Spray heads – 60%
Rotors – 70%
Bubblers – 80%
Rotary – 85%
Low Volume – 90%
Use Low Volume Irrigation
Very efficient for
non-turf applications
Apply precise amounts
of water slowly and
evenly at the root
Helps reduce weeds
and plant disease
Helps eliminate runoff
Helps plants thrive
Low Volume Irrigation- Issues
Clogging
Mis-alignment of lateral lines
Vandalism of exposed tubing
Low quality products- frequent replacement
required
Maintenance issues- Cleaning, aligning, repairing
Sub Surface Drip Irrigation
The latest technological innovation
Very useful for areas like medians, car parks,
planters
Ideal for shrub lines in lawn areas
Best suited for highway medians
No maintenance and very reliable
Out of sight- No vandalism, no damage
Proper Installation
Systems must be
properly installed and
configured to achieve
the most efficient use of
water
Use Certified Irrigation
Contractors (Irrigation
Association)
Proper Maintenance and Operation
Set systems to operate in
early morning
Periodic monitoring is
important
Routine inspections to
discover problems
Adjust schedules when the
seasons change
Adjust schedules when
plants change
Provide Optimum Water Pressure
Use pressure regulating devices
in high pressure situations
Every 0.3 bar reduction results in
6-8% lower water usage
Prevent misting & fogging
Use booster pumps in low
pressure environments
Ensures complete and efficient
water coverage
Design & Installation
“Head to Head” Coverage
Stretched Spacing
Irrigation Over-spray
Low Pressure
High Pressure
High Wind
Low Head Drainage
Design & Product Selection
• Translocation of materials• Evaporative cooling
• Water loss
What’s the function of transpiration ?
What’s the drawback ?
Transpiration
H2O
H2O
Water vapor
H2O
H2O
The function of stomates is gas exchange - primarily the acquisition of CO2 for photosynthesis. Stomates also transpire water which is the ecological trade-off.
Stoma or pores in the leaf surface allow CO2 to enter for photosynthesis and water vapor to escape through transpiration.
Space between cells is saturated with water vapor.
CO2
H2O
~ 99% of water consumed by plants is transpired.
Mineral45%
Organic5%
Soil gases25%
Water25%
Composition of an average loamy soil
% by volume
Solids PoreSpace
VC ‘97
Root Zone Pore Space
Maintaining pore space for soil gases
(O2) is critical to healthy root
function!!!
• Half the volume of a soil is pore space.
• Under ideal conditions ½ of the pore space is filled with water, the other ½ is filled with air.
After a heavy rain or irrigation
all pores are filled with water,
and the soil is saturated.
Over-watering can cause soils to be
constantly saturated which starves roots of oxygen
and restricts root growth and root function. This is
an unhealthy condition for turf!!!
After gravity drains the soil, ½ the pore
space is filled with water and ½ is filled with
air. This condition is “Ideal”.
Root Zone Pore Space
The landscape’s water requirement can be
measured through Evapotranspiration
(ET) calculations:
– ET is the amount of water lost to the plants use
through daily evaporation and transpiration
– ET is the measurement in mm of irrigation
required to supplement rainfall and maintain
desired soil moisture content
– ET and the efficiency of the irrigation system are
used to calculate the valve operating time
Plant Water Requirements
Calculating ET
The step-down method is a simple and easy way to conserve
water and save money
Take the base schedule already in use.
Subtract 2 minutes from each zone.
Monitor.
If still very green, subtract 2 more minutes.
Continue until you reach an acceptable level of colour and
health.
Step-Down Method
2 minutes from each zone can make a large difference.
54 litres/minute zone x 2 minutes = 108 litres
8 zones x 108 litres = 864 litres per irrigation day
864 litres/irrigation day x 7 irrigation days/week = 6048
litres/week
6048 litres/week x 40 weeks/year = 2,41,920 lites/year
2,41,920 litres/year x 100 homes = 24 Million litres saved
Water Savings
Benefits of Proper Irrigation
Tangible Benefits
– Water Savings
– Power Savings
– Labour Savings
– Reduced input costs
Intangible Benefits
– Greener landscapes
– Reduced dust pollution
– Cooling Effect
– Better aesthetics and working environment
Case Study- Lalbagh and Cubbon
Park
Initiated in 2003-05 by Bangalore
Development Authority
Computer controlled automatic irrigation
system installed in both parks
Over 1500 sprinklers in each park
Works in tandem with Sewage Treatment
Plant installed at the same time
Uses STP water for all irrigation needs
Lalbagh- Cost Benefit Analysis
System Cost was 158 Lakhs
Benefits
– Complete utilization of STP water
– Surplus water available for sale to other users
– Power savings of Rs.3 Lakhs per annum
– Labor Savings of Rs.15 Lakhs per annum
– Green Landscape throughout the year
– Reduced dust and a better environment
– System operational efficiently even after 10 years
Volkswagen Automotive, Pune
Installed in 2010
State of the Art Computerized Irrigation
System
25 acres of landscape
Changing Land use- Parking lots become
factories etc
Over 500 sprinklers and 20,000mts of Drip
Line
Volkswagen- Cost Benefit
Power savings of 25%- VFD pumps and Flo
Manager technology- around Rs.3 lakhs p.a
Automation was cheaper than manual in
capital costs
Only one person operates the entire system
replacing over 15 people.
Water consumption is reduced by 40% over
conventional system. This is based on data
of pre-irrigation usage and current usage
Volkswagen- Benefits
System is estimated to payback in 4 years
Green Landscapes throughout the year
Optimal utilization of the STP water, System
allows monitoring of consumption and
maintains logs of usage
Irrigation system has brought down dust
drastically and for the automobile plant, this
has been a major value addition for their
painting process quality
Intelligent Use of Water
Thank you.