The document discusses integrating rainwater harvesting (RWH) and stormwater management (SWM) infrastructure. It covers topics such as the need for water harvesting in India due to increasing water stress, the concepts of RWH and SWM, methods of RWH including storage and groundwater recharging, types of SWM techniques, benefits and challenges of an integrated approach, and a case study of New Delhi. The presentation contains 24 slides and references several additional resources on the topics.

2. CONTENTS
Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 01/24
• Why to Harvest Water
1
• Need for Harvesting Water
2
• Concept of Water Harvesting
3
• Rainwater Harvesting
4
• Stormwater Management
5
• Integrated Approach of RWH & SWM
6
• Modern Technologies being used
7
• Inferences: Benefits and Challenges
8
• Case Study: New Delhi
9

3. WHY to harvest Water? The Global Water Crisis
Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 02/24
Source: www.who.int/en
Source: www.odec.ca

4. WHY to harvest Water? Water Crisis in India
Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 03/24
Source: www.unwater.org

5. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 04/24
Source: www.indianexpress.com
Water Scenario in India
India’s population of 1.25 billion and an annual growth rate of 1.2%., is going to put huge pressure on the
already strained centralized water supply systems of the nation.
The urban water supply and sanitation sector is suffering from inadequate levels of service, an increasing
demand-supply gap, poor sanitary conditions and deteriorating financial and technical performance.
Why is there a Stress?
According to a World Bank study, of the 27 Asian cities with populations of
over 1,000,000, Chennai and Delhi are ranked as the worst performing
metropolitan cities in terms of hours of water availability per day, followed
by Mumbai and Kolkata. (Source: www.raiwaterharvesting.org)
WHY to harvest Water? Water Crisis in India

6. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 05/24
Source: www.watergraphs.com/2012
To overcome the inadequacy of surface water to meet our demands.
To arrest decline in ground water levels.
To utilize rain water for sustainable development.
To increase infiltration of rain water in the subsoil.
To improve ecology of the area by increase in vegetation cover.
NEED for Water Harvesting
Only 18% of India’s population has access to treated water.
We get a lot of Rain, yet we do not have Water…
Annual rainfall in India (1170mm) > Global average rainfall (800mm)

7. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 06/24
Source: CSE Water Harvesting Manual
CONCEPT of Water Harvesting
DEFINITION:
Water Harvesting refers to collection and storage of all the sources of water (rain, groundwater, etc.) and
prevention of water losses through evaporation and run-off aimed at conservation and efficient utilization of
existing water.
HOW MUCH WATER CAN BE HARVESTED?
The total amount of water received in the form rainfall over an area is called the Rainwater Endowment of that
area. Out of this, the amount that can be effectively harvested is called the Water Harvesting Potential.
Mathematically, Water Harvesting Potential= Rainfall (mm) * Collection Efficiency
For example, a plot of 100 sq.m. having 60% collection efficiency gets 600mm rainfall will harvest 36 cu.m.
(36,000 litres) of water ; which is twice the annual drinking water requirement of a 5 member family.

8. Broadly, rainwater can be harvested for two purposes:
1. Stored for ready use in containers above
ground or below ground
2. Charged into soil for withdrawal later
(groundwater recharging)
Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 07/24
Source: CSE Water Harvesting Manual
RAINWATER HARVESTING
RUNOFF
Runoff is the term applied to the water that flows
away from a catchment after falling on its surface
in the form of rain.
Runoff can be generated from both paved and
unpaved catchment areas of buildings.
During heavy rains, Rooftop runoff and Ground
runoff takes place.
Runoff from smooth tiled surface v/s a grass covered surface

9. Catchment Conduit Filter
Storage/
Recharge
ELEMENTS OF A TYPICAL WATER HARVESTING SYSTEM
Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 08/24
RAINWATER HARVESTING
•Catchment is the area which directly receives the rainfall.
It cab either be paved or unpaved.
•Conduits are the pipelines that connect catchment to the
water harvesting system.
•Filter prevents the debris from entering into the storage
or recharge facility.
METHODS OF HARVESTING WATER
1. Storing rainwater for direct use
2. Recharging groundwater aquifers
Source: CSE Water Harvesting Manual

10. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 09/24
Source: CSE Water Harvesting Manual
RAINWATER HARVESTING
PART 1: STORING RAINWATER FOR DIRECT USE
Rooftop harvesting is the oldest method of harvesting rainwater, where water is channelized towards storage.
Generally, water from paved surface is collected as it is free from bacteriological contamination. Also, mesh
filters are provided at the mouth of drain pipe to prevent the leaves and debris entering the system. RCC
storages are installed inside the basement of building or outside. PVC tanks are installed above ground.
Design parameters for storage tanks:
•Average annual rainfall
•Size of catchment
•Drinking water requirement
Quality of stored water contaminated by:
•Air pollutants
•Surface contamination (silt, dust, etc.)
First-Flush Device
It is simply a valve which is used
to ensure that the first spell of
rain is flushed out and does not
enter the system. It is done as
the first spell of rain carries with
it a relatively large amount of
pollutants from air.

11. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 10/24
RAINWATER HARVESTING
PART 2: RECHARGING GROUNDWATER AQUIFERS
All the water recharging structure aims at rainwater percolation in the ground either at shallower depths
through soil strata or to greater depths near groundwater. Some of these structures are:
Dug well
Recharge
Trenches
Permeable Surfaces

12. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 11/24
RAINWATER HARVESTING
PART 2: RECHARGING GROUNDWATER AQUIFERS
Source: CSE Water Harvesting Manual
Recharge Pits Soakaways

13. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 12/24
STORMWATER MANAGEMENT
Stormwater is water that originates during precipitation events and snow/ice melt, and results in abnormal
quantity of surface water during heavy rains.
Stormwater Management is a process of managing the quality and quantity of storm water by using both
structural and engineered control devices and systems to treat polluted storm water.
Source: Federal Interagency Stream Restoration Working Group (FISRWG) US.

14. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 13/24
STORMWATER MANAGEMENT
Source: http://www.lid-stormwater.net/
PRINCIPLE of Stormwater Management
SLOW SPREAD SOAK
LOW IMPACT DEVELOPMENT
Low Impact Development (LID) is an innovative stormwater management approach with a basic principle
that is modeled after nature: manage rainfall at the source using uniformly distributed decentralized
micro-scale controls.
AIM: LID's goal is to mimic a site's predevelopment hydrology by using design techniques that infiltrate,
filter, store, evaporate, and detain runoff close to its source.
LID allows for greater development potential with less environmental impacts through the use of smarter
designs and advanced technologies that achieve a better balance between conservation, growth, ecosystem
protection, and public health / quality of life.
POINTS TO PONDER:
LID is Simple and Effective
LID is Economical
LID is Flexible
LID is Balanced approach

15. Stormwater Management
Filtration
Gravel Filter
Chamber
Gravel Filter Strip
Vegetated Filter
Riparian Buffer
Conveyance
Bio Swale
Planters
Detention
Detention Pond
Dry Swale
Retention
Retention Pond
Constructed
Wetlands
Storage Tanks
RWH
Infiltration
Infiltration
Trench
Infiltration Basin
Pervious Paving
Rain Garden
Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 14/24
STORMWATER MANAGEMENT
Source: Federal Interagency Stream Restoration Working Group (FISRWG) US.
METHODS of Stormwater Management

16. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 15/24
STORMWATER MANAGEMENT
Source: www.ssswm.org/Stauffer B.
FILTRATION
Gravel Filter
Vegetated Filter
Riparian Buffer

17. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 16/24
STORMWATER MANAGEMENT
CONVEYANCE
Planters
Bio Swale
DETENTION
Detention Pond
Source: www.ssswm.org/Stauffer B.

18. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 17/24
STORMWATER MANAGEMENT
RETENTION
INFILTRATION
Retention Pond Underground Storage
Pervious PavingInfiltration Trench
Source: www.ssswm.org/Stauffer B.

19. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 18/24
INTEGRATED DESIGN APPROACH
RESIDENTIAL AREA
Source: www.lowimpactdevelopment.org

20. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 19/24
INTEGRATED DESIGN APPROACH
COMMERCIAL AREA
Source: www.lowimpactdevelopment.org

21. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 20/24
MODERN TECHNOLOGIES
Source: NOVATECH 2010, RBF Consulting
Green Roofs Porous Concrete
RWH Cistern
Underground Infiltration Device

22. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 21/24
INFERENCES
BENEFITS OF INTEGRATED APPROACH
Proper drainage of surface run-off
Collected water can be reused for groundwater recharge, urban landscaping or farming, etc.
Treatment of stormwater in a very early stage
Avoids damages on infrastructure (private properties, streets, etc.); flood prevention
Can be integrated into the urban landscape and provide green and recreational areas
CHALLENGES OF INTEGRATED APPROACH
Expert planning, implementation, operation and maintenance required
Depending on technique a lot of operation and labour is required
Risk of clogging infiltration system caused by high sedimentation rates
DESIGN APPROACH
Must be an important component of any facility planning
Must be initiated during the start of any facility’s design
In case of retrofitting projects, major emphasis must be given on how to achieve an adequate
solution without causing much damage to the existing system.

23. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 22/24
A Case of NEW DELHI
Source: www.oasisdesigns.org

24. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 23/24
A Case of NEW DELHI
Source: www.oasisdesigns.org

25. Presented By : Gaurav Singh Integrating RWH and SWM Infrastructure Slide no. 24/24
REFERENCES
•Reidy, P. C. “Integrating Rainwater Harvesting and Stormwater Management Infrastructure”. Low Impact Development for
Urban Ecosystem and Habitat Protection . 2009. http://dx.doi.org/10.1061/41009(333)28
•Daniel Apt. “Integrating Rainwater Harvesting and Low Impact Development “. RBF Consulting. SESSION 2.2, NOVATECH.
2010. http://documents.irevues.inist.fr/bitstream/handle/2042/35785/12204-341APT.pdf
• Prosser T., Morison P.J. and Coleman R.A. “Integrating stormwater management to restore a stream: perspectives from a
waterway management authority”. Freshwater Science, Vol. 34, No. 3 (September 2015), pp. 1186-1194 . 2015.
•http://www.jstor.org/stable/10.1086/682566
•Jensen M., Steffen J., Burian S., and Pomeroy C. “Do Rainwater Harvesting Objectives of Water Supply and
Stormwater Management Conflict?”. Low Impact Development 2010: pp. 11-20. 2010. http://dx.doi.org/10.1061/41099(367)2
•DeBusk K., Hunt W., Quigley M., Jeray J., and Bedig A. “Rainwater Harvesting: Integrating Water Conservation and Stormwater
Management through Innovative Technologies”. World Environmental and Water Resources Congress 2012: pp. 3703-3710.
2012. http://dx.doi.org/10.1061/9780784412312.372
•Stoner M. “Green Solutions for Controlling Combined Sewer Overflows”. Natural Resources & Environment, Vol. 21, No. 4
(Spring 2007), pp. 7-11, 59. http://www.jstor.org/stable/40924846
•Agarwal A., Narain S., “A Water Harvesting Manual”. Centre for Science and Environment, 2012.
http://www.cseindia.org/userfiles/UrbanRainwaterHarvestingReport.pdf
•Stenstrom M.K. “Stormwater”. Water Environment Research, Vol. 76, No. 5 (Sep. - Oct., 2004), p. 387.
http://www.jstor.org/stable/25045799