When you contribute to this project in-kind by nominating a school (or similar institution) that has roofs from which rainwater could be harvested, we intend to build rooftop rainwater harvesting system in the school (or similar institution).

Capacity of storage tank in the rainwater harvesting system is established based on 2 factors:

  • sufficient water (according to WHO, sufficient water is between 50 and 100 liters of water per person per day); and,
  • the collectible amount of rain.

Members of the community work with RaHa.

Pictures right: Rotary Club of Central Melborne-Sunshine of Victoria, Australia (District 9800),  Rotary Club of Osaka Hommachi, Japan and The Rotary Foundation brought clean water to Ulamona, Silanga, Bitokara and Lolobau Island. The 4 settlements are in Kimbe, the West New Britain capital. WNB is a large island to the North of Papua New Guinea and a PNG province. The project has 12 rainwater harvesting tanks, some of 45000L and some of 27000L. Rotary Clubs of Maffra and Sale, Victoria, Australia provided additional construction expertise and labour.

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THE WORKS INCLUDE:

  • ROOF PREPARATION

    Cleaning the corrugated metal roofs and painting it with rust-resistant paint. This seals the roof and lets water to easily slide off. It also reduces places for dust and debris to gather between rainfalls.

    Blueprint of house with rainwater harvesting system installed

  • GUTTERS AND DOWNSPOUTS

    Installation of gutters with gentle slope down to downspout. Whenever necessary, we cover the gutters with a leaf screen to keep out leaves and twigs for consistent water flow. This cuts down on maintenance of the system.

  • FIRST FLUSH DIVERTER

    At the bottom of the downspout, RaHa installs a diverter from the tank. When it first starts raining, this diverter is open. It lets the dust from the roof be washed away. Then the diverter is closed so the precious clean water fills the tank. The first flush diverter is one more step in the design to reduce maintenance and provide the cleanest of water.

  • TANK AND TAP

    RaHa uses only hygienic, long-lasting galvanized steel or zincalume steel tanks. These tanks have a life-span of over 60 years. Steel tanks withstand a wide range of temperatures, including fire. They can be transported in sections and assembled on site. They are superior to plastic’s 25-year life that suffers from UV decay. They are better than steel reinforced concrete that only has a 40-year lifespan.

    Tank sizes range from 12,000 to 253,000 litres. Smaller tanks can be built in two days. Larger ones will take five days. Trusses span the top to keep the tank’s shape. They are covered with sheet metal with access for periodic cleaning.

    To honor the business or entity that participate in bringing clean close water to the water starved, RaHa will place a sign on the tank with their (the business or entity) name or logo free of charge to the business or entity (see Climate’s marking on the tank in photo).

    A tap, a small distance from the tank, gives fresh, clean water to the village.

  • MEDIA

    Photos of the named tank and stories about the community are publicized to encourage others to nominate more communities or schools.

    RaHa will submit different press releases to get the optimum publicity for the bussiness’ charitable work. The stories will explain how the business participate in bringing clean water to this community or school.

    RaHa shares information about the community or school that receive RaHa clean pure water and what it means to them. You, the nominator, will also be recognized for your part.

    Some of the stories include ways people, businesses, or leaders nominate other communities, publicize the nomination or donate to support RaHa clean close water, which is vital to healthy life and prosperity.

    RaHa will promote the business further by posting the picture and press release on the RaHa website.

IN THE TANK, THERE ARE FOUR CLEANING COMPONENTS

The first cleaning component is the mechanical filter which retains or rinses certain coarser particles in the water due to its mesh width. Before filters, there are leaf separators.

Small particles flow through the leaf separator and filter, heavier ones accumulate on the tank floor, lighter ones (eg flower dust) rise and float on the water surface.

NOTE: Many times, these components are installed outside the tanks.

In order that the incoming water does not disturb the sediment on tank floor, the water is introduced as slowly as possible from the tank floor upwards.

This is done by the so-called calm intake.

Inlets pipes go to bottom of the tanks.

At end of the inlet pipes, there are provisions for the calming inlet.

The Calming Inlet performs several functions that are imperative to maintaining a high quality of water within rainwater harvesting tank.

The calming inlet acts as a mosquito barrier by creating a water trap between the inlet pipe and the tank, preventing mosquito entry into the tank.

Additionally, the calming inlet helps to introduce oxygen into the cistern water – helping to prevent stagnation – prevent anaerobic decomposition.

Perhaps most importantly, the calming inlet prevents any sediment bed from being disturbed. The calming inlet broadcasts the water up into the tank rather than allowing it to splash down. By keeping the sediment bed intact you help to improve the life of your pump – if any – since it will not be sucking up sediment, provided that a floating extractor is used.

Made of food quality polyethylene, the high quality construction of the calming inlets reduce water costs and the strain on water consumption.

Floating particles leave the tank at the overflow by means of the wanted skimming effect. This skimming effect “sucks” these particles off the water surface. At the same time, the siphon forms an odor seal as well as a rodent barrier with a channel connection.

The cleanest water in the tank is located between 15 cm above the sediment layer and 10 cm below the surface of the water and is taken from there with a floating extraction.

Extraction is done either with a submersible pump in the or with a suction and pressure pump outside the tank.

The floating extraction works even without pumps.

click to nominate for rooftop rainwater harvesting

click to see non-rooftop rainwater harvesting
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