Rainwater harvesting by hira

Dear Hira,

thank you for your proposal. 
Sustainable stormwater management practices as rainwater harvesting are very important and should be implemented across the world. I like your vision of having water harvesting for every building.

You gave a very detailed analysis of rooftop harvesting, its technical specifications and benefits.
However, the tech spec are too long and there is no clear line of how are you going to make your vision happen.
At some point, after the tech spec, your write about governmental policy. What is this part about? 

Try to further develop your idea and give an innovative turn on the 'how' question.
Is it the strategy on how you get the stakeholders on board, an innovative business model, a strategy to make it affordable for everybody or something fourth? Then you'll also be able to answer the other questions.

Try to look again at the key issues in the adaptation-2016 contest overview, might be of help.

Good luck,

Petra



 

Dear proposal author(s)

Thank you again for submitting your proposal to the adaptation contest.

Just a friendly reminder: you only have 6 days left to update and improve your proposal before the contest closure on May 23rd! 

Keep up the good work and let us know if you have any queries!

Best wishes,

Rita Marteleira

Adaptation Contest Fellow

Hira,

Last day to make refinements to your proposal. Looking forward to seeing the final version.

You have some good comments to respond to here. You suggest the actions to be take are worldwide. I suggest you start with a pilot demonstration, as Laurlea has proposed. Rainwater harvesting is a very locally-specific technology that requires tailoring to application.

Good luck.

Ferro Cement Structures

Background : In India total Number of Village Lacking Facility for drinking (potable )water estimated to be about 80,000 and our fifty percent villages facing problems such as Salinity brackishness no groundwater ,biologically contaminated water, source high iron content high fluoride content and Guinea worms etc.  Such a situation needs different type of planning and execution of the water-supply scheme for different village.

Rainwater is the pure form. Raw water available on the earth and Rainwater Harvesting system through roof and platform (micro) catchments is one of the economical and low cost solutions for drinking water problem which can easily be adopted in those areas of our country where enough rain-fall takes place.

SERC Ghaziabad has developed a modified Rainwater Harvesting system suitable for various areas in India. Reference and a series of training course are being organized for training the Kassar Trust Mankot field engineers and social workers in Construction Techniques for Rainwater Harvesting schemes and Ferro cement water storage Tanks in1989-90.After these training, the Kassar Trust organized series of training for N.G.O’s in Uttrakhand in 1991-93. Hira Panda  Mankot Bageshwar Uttrakhand  Pin  263642  is one of the participated in these trainings.

Ferro cement is thin walled type of reinforced cement concrete in which high strength cement and sand mortar  is reinforced with many layers of wire meshes woven or welded with small diameter steel wires. The mechanical – physical properties of Ferro cement make this material particularly suitable for construction of cylindrical water storage tanks and water filters at much lower cost than those constructed in R.C.C. masonry, steel or plastic. The method of construction is simple, easy to learn and can be carried out without the help of heavy or sophisticated equipment or electricity in Indian villages.

The properties of Ferro cement such as high resistance to cracking and impact, easy to carry construction using local labour and easily available materials make its application particularly suitable for use in water supply schemes in rural areas.

Ferro cement structures are generally 10-30 mm thick. The production cost for ferro cement tanks above 20,000 liters of capacity comes between Rs. 9.00 to 10.00 per liter.

Ferro cement structures which are useful for rain water harvesting schemes especially in hilly areas include;

-  Water Storage Tanks.

-  Filter Units.

-   Mini-check Dams.

-  Roofing Units etc.

 

 

Hira Panda Mankot has been working in the field of development of F.C. structures useful in rural development in Uttrakhand hills since 1993 .Large number of  water tanks, roofing units,irrigation-cum-drainage units ,manhole cover, leak-proof treatment for water tanks , water filters  etc. have been developed.

Ferro cement Water Storage Tanks

Development of water sources scheme and its maintenance is a time consuming and costly process and potable water produced is a valuable commodity in terms of cost and its importance to human life. Wastage or deterioration of its quality must be prevented at any cost and it is one of the important tasks in the water management system. Potable water can again become harmful incase it is stored in unhygienic condition/storage structure.

Hence, proper storage of water in safe and hygienic conditions, in closed containers has great importance in water-supply schemes for Indian villages. Several types of tanks are being used for this purpose at present. These include tanks constructed with reinforced cement concrete, brick/stone masonry, steel G.I. sheet, asbestos, plastic and Ferro cement. Use of traditional water storage structures such as tankas, maths water jars, metal (brass/copper) containers are also continuing in Rajasthan, Madhya Pradesh ,Gujarat ,Uttar Pradesh, Uttrakhand etc. Construction of R.C.C. tanks requires use of expensive frame-work (especially for cylindrical tanks) and skilled labour. These tanks are also quite heavy in weight and need stronger supporting structures. Metal tanks require sophisticated equipment and skilled labour for fabrication, provide poor thermal insulation and their service life even with regular maintenance is quite short. Raw material for metal tanks has to be bought from far off places in most of the cases. Asbestos tanks are susceptible to frequent damages. HDP tanks are costly and their transport from factory to site is difficult and needs extreme care. These get damaged easily. Besides these drawbacks, the tanks mentioned above are relatively expensive in cost and do not suit adoption for use in rural conditions.

 

Some of the significant characteristics which distinguish Ferro cement tanks from ordinary reinforced concrete are:-

 

1. Its thin section and reinforcement provided in form of several layers of thin wire meshes create a high specific surface of the reinforcement and because of this, Ferro cement act as a homogenous material within wider limits than ordinary R.C.C. and, therefore, resist higher tensions before cracking occurs.
2. It has a higher impact resistance than ordinary R.C.C. because of its higher energic absorption capacity. Any accidental damage occurring in a Ferro cement surface is localized to a smaller area and can be easily repaired by chipping off cracked area for exposing the meshes and again plastering the damaged area.
3. Any desired shape can be reproduced in Ferro cement by preparing a skeletal cage of that shape and by applying mortar over it.
4. In Ferro cement, materials used are cement, sand, steel, wires/bars, wire meshes and some chemicals which are generally available in most of the places.

 

Construction work can be undertaken by using local labour. Many of the structures can also be done on self help basis by the family of users.

 

Apart from the above, Ferro cement tanks and filters are cheapest and easiest to construct and maintain even in difficult areas like villages in plains and hills. Structures constructed in remote hill areas in Uttrakhand, Manipur, Meghalaya have demonstrated that the unskilled locals can be easily trained in this construction technology. Being a labour intensive technology, construction of Ferro cement structures provide employment to local unemployed youth in rural areas, the rural women can also be trained in the casting techniques for Ferro cement structures. Amount of materials to be handled is quite low in weight resulting in low cartage cost

 

 

F.C. tanks are produced using ‘skeletal cage plastered by hand’ method in most of the countries outside India. The thickness for such units comes to not less than 20 mm even for the smaller capacity tanks and the casting progress is slow (reference 2 and 4 ). Tanks of capacities above 500 liters, cast with this technique cannot be transported easily. For overcoming these problems, SERC has developed there casting techniques for fabrication of walls for F.C. tanks up to 20,000 liters capacity. Use of SERC techniques result in reduction of wall thickness, improvement in compactness of Mortar, improved performance, reduction of construction time and cost when compared to the traditional casting system. Two of these processes are covered by Indian Patent No.14250. These techniques have been released to more than 50 licensees through NRDC of India, New Delhi and about 35 of them are in production.

 

F.C tanks developed by SERC (G) are cylindrical in shape. Tanks cast with semi-mechanised process and segmental systems are assembled using pre-fabricated components. The base of tank is generally cast using R.C.C. but can also be cast with Ferro cement for tanks of capacities up to 2,500 liters. Tank walls are cast using either of the three casting methods:

 

--- SERC semi-mechanised process for producing F.C. cylindrical units.

--- SERC precast segmental shell elements casting and assembling these into cylindrical          units.

--- Tem former method for casting walls of Ferro cement tanks.

 

 

SERC Semi-Mechanised Process for Cylindrical tanks :

In the semi-mechanised process, a simple hand operated equipment (fig 1) is used in which the galvanized woven wire fabric (square woven mesh) from a tightly wrapped roll continuously wound on to a cylindrical openable mould made from wooden body covered with G.I. sheet. Rich cement and sand mortar (1 cement : 2 silt free medium coarse sand) mixed with pore sealing compound and plasticizer is simultaneously applied on the wire mesh. The winding of mesh and application of mortar goes on continuously in stages. The first layer of mesh is slightly lifted over the mould by inserting MS flat (20 x 3 mm) between the mould and the first layer of mesh. This ensures a cover over the innermost wire mesh layer. While applying mortar over the mesh layers it is ensured that each layer is covered by at least a 3 mm thick mortar layer on either side. When the desired thickness of Ferro cement unit is obtained, the end of the wire mesh is anchored to the next below layer by stitching it with G.I. tying wire and the joint is covered by mortar layer. A minimum of two layers of 20 g x 12 x 12 mm mesh is provided in thickness of 10 mm. Casting of thicker units providing reinforcements like welded wire fabric, G.I. wire, M.S. rounds up to 6 mm dia, M.S. angle edging etc. could also be provided as extra strengthening measures during the casting of the unit itself, units are demoulded after 24 hours.

The semi-mechanised processes is suitable for factory production of tanks up to 2,500 liters capacity as the fully  precast wall units of diameter up to 1.2 meter can be easily handled and transported manually. In case of tanks up to 5,000 liters capacity the casting equipment may be shifted to site and the wall units may be cast there itself.

For assessing the water retention and thrusting bearing capacity of a tank produced with SERC semi-mechanised process. For longer period, an underground tank cast with SERC process (capacity 2,500 liters) has been kept under test since 1974. Water was filled around the tank from 1974 to 1984 for external pressure and for testing the leakage through walls which are only 10 mm thick. The inside of the tank has been kept empty. Since 1984, the outside cavity has been filled with coarse sand, saturated with water. No deterioration or leakage has been observed. Behavior of large numbers F.C. tanks has been observed for period ranging from 20 to 35 years and has been found to be satisfactory.

The cylindrical F.C. units produced using SERC processes are also used as walls for vertical cylindrical septic tanks, biogas digesters, well lining rings, bins and circular shuttering/frame-work etc. Because of its multipurpose usefulness, establishment of small scale industries in rural areas are possible.

The base unit for the tank is cast over a leveled platform with reinforced cement concrete. Reinforcement and thickness of the base will depend upon the size of the tank and also on the supporting conditions. For larger tanks base units can be cast in segments with projected steel bars. These pre cast units are assembled at site after providing laps for projected and concrete is filled in the joint area. The roofing units for these tanks, the cover for manhole provided in the roof of the tank, are also cast in Ferro cement over masonry or soil deposit mortar lined moulds.

 

Hira Panda Mankot  Bageshwar . Field Engineers, technicians Construction in Uttrakhand 25000 Nos of Rainwater Harvesting schemes and Ferro cement water storage Tanks.