rain water harvesting

Urban Rain water Harvesting

By

Bana Consulting Pvt Ltd, Pune.208, Amar Neptune,1/1/6 Baner Pune 411045

Email: [email protected]

Business Associate ofFuraat Earth Pvt Ltd

mailto:[email protected]

Rain Water harvesting is the deliberate collection and storage of rainwater that runs off on natural or manmade catchment areas. Catchment include rooftops, compounds, rocky surface or hill slopes or artificially prepared impervious/ semi-pervious land surface. The amount of water harvested depends on the frequency and intensity of rainfall, catchment characteristics, water demands and how much runoff occurs and how quickly or how easy it is for the water to infiltrate through the subsoil and percolate down to recharge the aquifers. Moreover, in urban areas, adequate space for surface storage is not available,not deep enough to accommodate additional rainwater to recharge the aquifers, rooftop and runoff rainwater harvesting is ideal solution to solve the water supply problems.

Rainwater Harvesting

This how water gets recharged in to the earth

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. To maintain green cover in the city (Urban area).

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

Urban rainwater harvestingUrban centres in India are facing an ironical situation today. On one hand there is the acute water scarcity and on the other, the streets are often flooded during the monsoons. This has led to serious problems with quality and quantity of groundwater.

This is despite the fact that all these cities receive good rainfall. However, this rainfall occurs during short spells of high intensity. (Most of the rain falls in just 100 hours out of 8,760 hours in a year). Because of such short duration of heavy rain, most of the rain falling on the surface tends to flow away rapidly leaving very little for recharge of groundwater. Most of the traditional water harvesting systems in cities have been neglected and fallen into disuse, worsening the urban water scenario. One of the solutions to the urban water crisis is rainwater harvesting - capturing the runoff.

Why RWH in urban area?

In areas where there is inadequate groundwater supply or surface resources are either lacking or insufficient, rainwater harvesting offers an ideal solution.

Helps in utilising the primary

source of water and prevent the runoff from going into sewer or storm drains, thereby reducing the load on treatment plants.

Reduces urban flooding.

Recharging water into the aquifers help in improving the quality of existing groundwater through dilution.

Water harvesting potential (L) = Area (m2) X Rainfall (mm) X Runoff coefficient

COLLECTION AREA AND EFFICIENCY

AREA RUN OFF COEFFICIENT

Roof Top 0.85 to 0.95

Paved Area 0.50 to 0.75

Bare Ground 0.10 to 0.20

Green Area 0.05 to 0.10

Rain water collection

1000 mtr2 area x 100 mm rain fall x 0.75= 75000 ltrs of fresh water

Average rain fall record in IndiaRain Fall

Quality Issues in rain water harvesting

Catchment area Pollution Control

Roof Top Bird dropping, Phenolic materials leaching from the roofing

Keep the roof clean, flush off first rains, Don’t use tar based coatings on the roof.

Paved area Dust, mud, oil residuals, organic waste (leaves debris),tar etc.

Keep paved area clean. Keep oil or chemicals storage away from the runoff area.

Bare Ground Mud, sand particles, oil organic waste,

Control soil erosion by hardening the surface. Keep the surface free from plastic or organic waste.

Green Cover Dust, Organic waste (grass leaves debris), soil particles, chemicals etc.

Remove the grass and leaves waste from the green area. Don’t use pesticides or fertilizers.

Right way of Rain water recharging

👎 It was noticed that in normal course it take 20 years to percolate water 100 feet

👍 With proper rain water recharge system water can percolate within few weeks.

EFFECTIVE WAYS TO HARVEST RAIN WATER

Cross section of the System

Gravel filtration

Graded sand

filtration

CG screen

filtration

Filtered water outlet

Rain water inlet

Conventional Well

Vs

Furaat Modular System

Visuals of Conventional & Furaat Modular System

Conventional System Vs Furaat Modular System

Conventional Well

• Considering the projects in urban areas, size 4x4x4 rectangular or round size occupies more area and becomes expensive.

• In the season of monsoon, muck

is seen settled on filter head, hence system gets choked.

• There is no back wash system


• FMS is scientific and compact. Systems rise vertically with maximum diameter of 1.5 meters.

• Furaat has specially designed primary module for controlling the muck.

• Furaat system can be back wash easily by domestic workers.


Conventional Well

• Maintenance is expensive and time consuming as it requires a civil team.

• Unsafe in underground operations and therefore needs special preparation to enter inside the system.

• Unhygienic conditions due to ponding in filter pit.


• Maintenance is easy and can be done by 2 domestic or non-skilled labors with the help of Furaat service manual with a cleaning time of 2 hours.

• Human safety is the prime concern, therefore FMS is designed with integral ladder in the system.

• Furaat system have closed lids, therefore protects contamination in harvesting.


Conventional Well

• Construction time and brick masonry takes 20 to 30 days.

• Recharge wells with 6% to 8% open area with metal slotted casing pipe reduces percolation due to corrosion.

• No control on corrosion affects durability of recharge structure


• FMS are installed in 3 hours by readymade precast modular slabs with the help of 3 non skilled persons.

• Furaat installs efficient well with low carbon galvanised screen with 48% open area.

• Furaat provides on-site 2000 PSI marine coating on casing pipes for durability


Conventional Well

• No scientific measurement of re-charge.

• As the structure is non-functioning, it becomes a national waste.

• It is costly and stationery.


• Furaat systems are scientifically tested @ 30,000 litre per hour.

• Efficient functioning of FMS aims to make India water positive.

• Furaat system are cost effective, can be shifted to other site.

Installations

Bana Consulting Pvt Ltd 9970092866

THANK YOU..

Dr. Balajith B. ShettyBana Consulting Pvt Ltd.

208, Amar Neptune, 1/1/6 Baner, Pune 411045.

91 997009286691 20 27290117

[email protected]

Business associate of Furaat

rain water harvesting

Environment