Rain Water Harvesting

5.6.2012

Dr. N. Sai Bhaskar ReddyCEO, GEOhttp://e-geo.org

Workshop for Rain water Harvesting campaign with United Federation of Resident Welfare Associations (U-FERWAS)

Water and Land Management Training and Research Institute (WALAMTARI), Govt. of AP

Climate Change and drought

2

Meteorological DroughtMeteorological drought is the amount of dryness and the duration of the dry period. Atmospheric conditions that result in deficiencies of precipitation change from area to area. 

Hydrological Drought Hydrological drought is associated with the effects of periods of precipitation shortages on water supply. Water in hydrologic storage systems such as reservoirs and rivers are often used for multiple purposes such as flood control, irrigation, recreation, navigation, hydropower, and wildlife habitat. Competition for water in these storage systems escalates during drought and conflicts between water users increase significantly. 

Agricultural DroughtAgricultural drought mainly effects food production and farming. Agricultural drought and precipitation shortages bring soil water deficits, reduced ground water or reservoir levels, and so on. Deficient topsoil moisture at planting may stop germination, leading to low plant populations. 

Socioeconomic Drought Socioeconomic drought occurs when the demand for an economic good exceeds supply as a result of a weather-related shortfall in water supply. The supply of many economic goods, such as water, forage, food grains, fish, and hydroelectric power, depends on weather. Due to variability of climate, water supply is sufficient in some years but not satisfactory to meet human and environmental needs in other years. The demand for economic goods is increasing as a result of increasing population. Supply may also increase because of improved production efficiency and technology. 

The Barefoot College, Tilonia

STRUGGLE FOR WATER

Water sharing – strategies for survival-Community borewells-Apartments / complexes-Street borewells

The Barefoot College, Tilonia

The Barefoot College, Tilonia

POLLUTED WATER

Every drop counts

uk-energy-saving.com

• India has 2% of world’s land, 4% of freshwater, 16% of population, and 10% of its cattle.

• Geographical area = 329 Mha of which 47% (142 Mha) is cultivated, 23% forested, 7% under non-agri use, 23% waste.

• Per capita availability of land 50 years ago was 0.9 ha, could be only 0. 14 ha in 2050.

INDIA’S LAND RESOURCE, IRRIGATION AND FOOD

PRODUCTION

Out of cultivated area, 37% is irrigated which produces 55% food; 63% is rain-fed producing 45% of 200 M t of food.

In 50 years (ultimate), proportion could be 50:50 producing 75:25 of 500 M t of required food.

Freshwater management in India

Anupma Sharma

Water Conservation

Watershed management

Water quality conservation

Inter basin water transfer

GW management

Recycle and reuse of water

Public involvement and capacity building

What Is Rainwater Harvesting?

RWH technology consists of simple systems to collect, convey, and store rainwater. Rainwater capture

is accomplished primarily from roof-top, surface runoff, and other surfaces.

RWH either captures stored rainwater for direct use (irrigation, production, washing, drinking water, etc.) or is recharged into the local ground water and is call artificial recharge.

In many cases, RWH systems are used in conjunction with Aquifer Storage and Recovery (ASR). ASR is the introduction of RWH collected rainwater to the groundwater / aquifer through various structures in excess of what would naturally infiltrate then recovered for use

Why Rainwater Harvesting?

Conserve and supplement existing water resources

Available for capture and storage in most global locations

Potentially provide improved quality of water

Supply water at one of the lowest costs possible for a supplemental supply source.

Capturing and directing storm water (run-off) and beneficially use it

Commitment as a corporate citizen - showcasing environmental concerns

Public Mandate (India)

Replenishing local ground water aquifers where lowering of water tables has occured

Why Not RWH?Not applicable in all climate conditions over the world

Performance seriously affected by climate fluctuations that sometimes are hard to predict

Increasingly sophisticated RWH systems (ASR) necessarily increases complexities in cost, design, operation, maintenance, size and regulatory permitting

Collected rainwater can be degraded with the inclusion of storm water runoff

Collected water quality might be affected by external factors

Collection systems require monitoring and continuous maintenance and improvement to maintain desired water quality characteristics for water end-use

Certain areas will have high initial capital cost

.ppt (16)

Condensation

Precipitation

Evaporation

Surface Water

Infiltration

Evapotranspiration

Let’s take a look atThe Water

Cycle

Consumption

Surface Runoff

Groundwater

Sea water intrusion

Design and Feasibility Criteria

Collection Area

Rainfall

Demand

Primary Use (Direct Use, Artificial Recharge (AR) or Aquifer Storage and Recovery (ASR))

Storage capacity

Level of Security - risk of the storage tank running dry

Collection Area and Characteristics

Measure Area

Runoff Characteristics• Roof top 0.75 – 0.95• Paved area 0.50 – 0.85 • Bare ground 0.10 – 0.20 • “Green area” 0.05 – 0.10

Water harvesting potential(m3) = Area (m2) X Rainfall (m) X Collection Efficiency

Quality Issues

Roofs contain: bird droppings, atmospheric dust,

industrial and urban air pollution

Operational Procedures and Design Considerations

Screen to prevent birds,

animal and insects;

Lead based paint must not be used on the

roof;

Tar based roof coatings and materials should

not be used – Phenolics and other organics can leach from materials

If roofs painted with acrylic paints, new concrete or metal roofing - first few rainfalls should not be

collected to avoid metals, detergents, and other

chemicals

GRAVEL AND SAND

CHARCOAL

SAND

GEO WATER FILTER

THREE 15 LITER TIN CANS, SAND, GRAVEL , TAP AND PVC PIPE

Operational Procedures and Design Considerations

Storage tank – dark materials to exclude light and algae formation

Corrosion resistant materials

Tank in protected shaded area –

lower temperature

For multiple storage tanks –

design for frequent turnover

Storage

1. Ponds and Reservoirs

2. Artificial recharge of Groundwater

3. Water Tanks

4. Rainwater runoff in surface water

5. Rainwater runoff in groundwater

6. Rainwater runoff in tanks

7. Effluent in surface water

8. Effluent in ground water

Every drop counts

Every drop counts

Every drop counts

Every drop counts

Jn nurm – URBAN RAIN WATER HARVESTING

Tackle water shortage during summers

Recharge aquifers

Reduced power consumption in pumping water

Reduced water logging and flooding in low lying areas

Reduced erosion

Improved Groundwater quality through dilution. Eg: Coastal areas

Means of water conservationNew dams - inter-basin

transfer

Groundwater - underdevelope

d

Demand Management

Water savings - increase in

efficiency, reduce evaporation.

Water productivity - increases in crop per drop

Virtual water – Food

production

Water Conservation…

Prof. T. I. Eldho , Prof. T. I. Eldho ,

Install small shower heads to reduce the flow of the water. Water in which the vegetables & fruits have been washed - use to water the flowers & plants.

At the end of the day if you have water left in your water bottle do not throw it away, pour it over some plants.

Re-use water as much as possible

Change in attitude & habits for water conservation

Every drop counts!

!!

Water Conservation

Water conservation interventions includes contour trenches, gully

plugging, vegetative and field bunding, percolation tanks.

Overall land treatment against potential area is varying between 40-60%.

45%

30%

25%

Private land Fallow land Forest land

28%

65%

2% 5%

Contour bunding Gully pluggingStaggered trenching Level terraces

Type of land ownership for soil and water conservation

measures

Techniques of soil and water conservation measures Prof. T. I. Eldho , Prof. T. I. Eldho ,

Borewell recharge filters

Roof top rainwater harvestingAt AVANI, Berinag, Uttarakhand

RECHARGE WELLS

The Barefoot College, Tilonia

While it would normally take between 20-30 years for water to percolate 100 feet from an

open tank, it has been noticed in an open well

300,000 litres can percolate to the same depth

within a week.

THANK YOU