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.