Presented by:M.Saeed UllahRoll number: 3746

Department: BS Agriculture SciencesSemester: 5th(Agronomy)

Subject: Irrigation Agronomy(AGRON-504)

• Reduces water bills. • Sets an example for students and parents. • Improves groundwater table if rainwater is recharged. • Improves groundwater quality by dilution (rainwater has nearly neutral pH and zero hardness).

Recharge if there’s excess

The concept is simple Collect

Store

Use

Catchment – rooftop

Transportat ion – Down take pipes

Filters – First flush device

Leaf and grit filter

Storage – Tank / well

Components

Rain Water Collected From Both Sides of the Roof

W

Rain Water Collected From one Side of the Roof

Amount of rainfall(mm)

x =W

Catchment Area (m2) Volume of water received(Litres)

The water that leaves the rooftop may be 65 – 90% of the water that falls on it

The water that leaves the rooftop may be 65 – 90% of the water that falls on it

Roof material absorbs some water

More water loss if roof is flat

Evaporation losses

Remove leaves, plant debris, bird and animal droppings, dead rodents or birds

No tar / bitumen on the roof

No chemical pesticides or fertilizers for rooftop garden

Transportation

Pipe size is calculated based on peak flow rates

(rooftop area and peak rainfall rate)

Gutter (open on top)

Downtake pipe (cylindrical)

PVC pipes preferred. Do not use lead pipes

Harvesting SystemBroadly rainwater can be harvested for two purposes•Storing rainwater for ready use in containers above or below ground •Charged into the soil for withdrawal later (groundwater recharging)

Source: A Water Harvesting Manual For Urban Areas

RAIN WATER HARVESTING TECHNIQUES :There are two main techniques of rain water

harvestings. Storage of rainwater on surface for future use. Recharge to ground water.The storage of rain water on surface is a traditional

techniques and structures used were underground tanks, ponds, check dams, weirs etc

Recharge to ground water is a new concept of rain water harvesting and the structures generally used are :-

Pits :- Recharge pits are constructed for recharging the shallow aquifer. These are constructed 1 to 2 m, wide and to 3 m. deep which are back filled with boulders, gravels, coarse sand.

Trenches:- These are constructed when the permeable stram is available at shallow depth. Trench may be 0.5 to 1 m. wide, 1 to 1.5m. deep and 10 to 20 m. long depending up availability of water. These are back filled with filter materials.

Dug wells:- Existing dug wells may be utilised as recharge structure and water should pass through filter media before putting into dug well.

Hand pumps :- The existing hand pumps may be used for recharging the shallow/deep aquifers, if the availability of water is limited. Water should pass through filter media before diverting it into hand pumps.

Recharge wells :- Recharge wells of 100 to 300 mm. diameter are generally constructed for recharging the deeper aquifers and water is passed through filter media to avoid choking of recharge wells.

Recharge Shafts :- For recharging the shallow aquifer which are located below clayey surface, recharge shafts of 0.5 to 3 m. diameter and 10 to 15 m. deep are constructed and back filled with boulders, gravels & coarse sand.

Lateral shafts with bore wells :- For recharging the upper as well as deeper aquifers lateral shafts of 1.5 to 2 m. wide & 10 to 30 m. long depending upon availability of water with one or two bore wells are constructed. The lateral shafts is back filled with boulders, gravels & coarse sand.

Population increase Industrialization Urbanization

(a) Increase in per capita utilization(b) Less peculation area

In places where rain fed/ irrigation based crops are cultivated through ground water

Decrease in surface area of Lakes, talab, tanks etc.

1

Deforestation(i) Less precipitation(ii) Absence of Barriers

(a) Rain drops checked by leaves of tree(b) Water slowly descends through twigs & trunk© Humus – acts as reservoir(d) Tiny creatures – helps percolation

2 21

1 hectare of forest-6-7 Lac ton of water(after filtering) top layer can hold 1.2 Lac tons of water

Rain Water Harvesting– AdvantagesRain Water Harvesting– Advantages Rain Water Harvesting– AdvantagesRain Water Harvesting– Advantages

1.Provides self-sufficiency to water supply

2.Reduces the cost for pumping of ground water

3.Provides high quality water, soft and low in minerals

4.Improves the quality of ground water through dilution when recharged

5.Reduces soil erosion & flooding in urban areas

6.The rooftop rain water harvesting is less expensive & easy to construct, operate and maintain

7. In desert, RWH only relief

8. In saline or coastal areas & Islands, rain water provides good quality water

Appropriate Technology

Water conservation and groundwater recharge techniques

Water harvesting cum supplementary irrigation techniques

Rain water is the ultimate source of fresh water Potential of rain to meet water demand is

tremendous Rain water harvesting helps to overcome water

scarcity To conserve ground water the aquifers must be

recharged with rain water Rain water harvesting is the ultimate answer

3

1 By providing pipe water system with source (electric based)(a) Surface water(b) Deep tubewells2 Recharging stratas through rainwater harvesting

methods(No. of villages of lower range concentration can be

decreased)3 Storing rain water for drinking purpose

(a) In areas where electricity problem is more(b) In areas where concentration is more © In areas where PWS is uneconomical (d) In areas where dependable source is not available

36

ATTRIBUTES OF GROUNDWATER : There is more ground water than surface water Ground water is less expensive and economic

resource. Ground water is sustainable and reliable source

of water supply. Ground water is relatively less vulnerable to

pollution Ground water is usually of high bacteriological

purity. Ground water is free of pathogenic organisms.

Ground water needs little treatment before use. Ground water has no turbidity and colour. Ground water has distinct health advantage as

art alternative for lower sanitary quality surface water.

Ground water is usually universally available. Ground water resource can be instantly

developed and used.There is no conveyance losses in ground water based supplies.

Ground water has low vulnerability to drought. Ground water is key to life in arid and semi-arid

regions. Ground water is source of dry weather flow in

rivers and streams.

Clamp gutters and down take pipes well

Keep gutters clean of leaves

See that leaves do not clog a down take pipe (Jaali or leaf filter may be needed at rooftop discharge

point but this may also be a problem if leaf debris collects on it and water stagnates on the roof)

Gutters and down take pipes should be gently sloping towards the storage tank, so that there is no stagnation of water in the pipe

http://www.rainyfilters.com/rainwater.aspx

Gravel

Sand

Inlet

Out flow

Over flow

Gravel

Recharge tank

Filter

Storage tank

Down take pipes

First flush

Check and clean filters before and after each rainy season

Make your own filter with sand, charcoal and gravel

Or

Buy a filter off the shelf

The first rain carries with it a lot of filth from the rooftop and dissolved air pollutants

This rainwater should be diverted away from the storage tank using a first flush device.

Some filters have a first flush system integrated in them

Check and clean first flush devices regularly.

First flush standpipe

Depends on

Rainwater availability

Water requirement

Budget (storage tank is most expensive part of (rwh system)

Available space and aesthetics

Excess water can be diverted into a groundwater recharge system

Do a water audit to check water requirement.

Above ground

Ground level or Intermediate floor level

Just below roof

Below groundSave on pumping cost

Durable and no leaks

Built on a strong and stable substrate that can support the tank filled with water

Opaque – presence of light can cause algal growth in tank

Secure and impervious cover

Vents to be covered with insect proof mesh

Located as close as possible to demand and supply points to reduce plumbing

• Overflow pipe should be provided close to the top, to reduce dead space.

• Overflow pipe diameter should be equal to inlet pipe diameter

• Overflow pipe should lead excess water away from the foundation of tank and other buildings. Preferably the overflow should be led into a groundwater recharge system or a garden

• There will be sedimentation in the tank. Taps and pipes to draw water from the tank should not be very close to the bottom to prevent sediments from entering the plumbing system and clogging it.

If used for drinking, it is absolutely necessary to check water quality in a lab and treat as required

Some changes may be required in plumbing, if retrofit

Clean rwh system regularly Rooftop everyday Tank after a rainy season Filter after a rainy season

DO IT NOW!

I m really thankfull to my dear sir (Ayub sahib) Who give me opertunity to present my skill

and guide me how to make assigment and presentation .