CSA Symposium 2016 -Shawn Miller Day 1 Session 3
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This document discusses rainwater harvesting as a solution to water shortages caused by factors like deforestation, population growth, and urbanization. It defines rainwater harvesting as collecting rainwater when it falls and storing it for later use. The document outlines the objectives of rainwater harvesting such as meeting increasing water demands and recharging groundwater. It also describes various components of roof rainwater harvesting systems including catchments, transportation mechanisms, filters and different types of filters. Finally, it provides examples of rainwater harvesting implementations and their uses.
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CSA Symposium 2016 -Shawn Miller Day 1 Session 3
- 1. Rainwater Harvesting Presented by Shawn Miller, Dip. Eng., B. Eng.
- 2. Why is there a water shortage? Deforestation Population increase Industrialization Urbanization - Increase in per capita utilization and less peculation area In places where rain fed/ irrigation based crops are cultivated through ground water Decrease in surface area of Lakes, Rivers, Dams etc.
- 3. What is the solution? 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
- 4. What is Rainwater Harvesting? Rainwater is collected when it falls on the earth, stored and utilized at a later point. It can be purified to make it into drinking water, used for daily applications and even utilized in large scale industries. The simplest method for a rainwater harvesting system is storage tanks. In this, a catchment area for the water is directly linked to cisterns, tanks and reservoirs. Water can be stored here until needed or used on a daily basis.
- 5. Major Objectives of Rainwater Harvesting 1. Meet the increasing demands of water 2. Reduce ground water contamination 3. Reduce soils erosion 4. Supplement domestic water needs 5. Avoid flooding of roads
- 6. Major Objectives of Rainwater Harvesting 6. Supplement ground water supplies during lean season 7. Reduce run off loss 8. Raise the water table by recharging ground water 9. Reduce the run-off which chokes the drain 10. Reduce groundwater pollution
- 7. Benefits of Rainwater Harvesting 1. Easy to Maintain: Systems for the collection of rainwater are based on simple technology. It is important to do so since drinking water is not easily renewable. 2. Reduces Water Bills: For many families and small businesses, rain water harvesting leads to a large reduction in their utilities bills. On an industrial scale, harvesting rainwater can provide water for many operations to take place smoothly without depleting water sources.
- 8. Benefits of Rainwater Harvesting 1. Suitable for Irrigation: Most rooftops act as a workable catchment area, which can be linked to the harvesting system. 2. Reduces Floods and Soil Erosion: Rainwater may be collected in storage tanks to reduce floods in low lying areas. This also reduces soil erosion and contamination of surface water with pesticides and fertilizers from rainwater run-off which results in cleaner lakes and ponds. 3. Reduces Demand on Ground Water: With an increasing population, the demand for water is also continuously increasing. Rainwater harvesting reduces the demand on ground water resources.
- 9. Methods of Rainwater Harvesting There are two main methods of harvesting rainwater 1. Surface runoff harvesting 2. Roof top rainwater harvesting
- 10. Surface Runoff Harvesting In urban areas rainwater typically flows away as surface runoff. This runoff could be caught and used for recharging aquifers by adopting appropriate methods.
- 11. Roof Top Rainwater Harvesting The rainwater is collected from the roof of the building in this method. It can either be stored in a tank or diverted to an artificial recharge system. This method is very cost efficient and effective if implemented properly.
- 12. Components of the roof top rainwater harvesting The system mainly constitutes of : Catchments Transportation First flush Filter
- 13. Components of the roof top rainwater harvesting • Catchments - The surface that receives rainfall directly is the catchment of rainwater harvesting system. It may be terrace, courtyard, or paved or unpaved open ground. The terrace may be flat RCC/stone roof or sloping roof. Therefore the catchment is the area, which actually contributes rainwater to the harvesting system. • Transportation - Rainwater from rooftop should be carried through down take water pipes or drains to storage/harvesting system. Water pipes should be UV resistant (ISI HDPE/PVC pipes) of required capacity. Water from sloping roofs could be caught through gutters and down take pipe. At terraces, mouth of the each drain should have wire mesh to restrict floating material.
- 14. Components of the roof top rainwater harvesting First Flush – The first shower of rains needs to be flushed-off to avoid contaminating storable/rechargeable water by the probable contaminants in the atmosphere and the catchment roof. First rain separators should be made at outlet of each drainpipe. Filter - After first flushing of rainfall, water should pass through filters to remove turbidity, colour and microorganisms. A gravel, sand and ‘netlon’ mesh filter is designed and placed on top of the storage tank. It removes silt, dust, leaves and other organic matter from entering the storage tank.
- 15. Types of Filters Sand Gravel Filter These are commonly used filters, constructed by brick masonry and filleted by pebbles, gravel, and sand as shown in the figure. Each layer should be separated by wire mesh. Charcoal Filter Charcoal filter can be made in-situ or in a drum. Pebbles, gravel, sand and charcoal as shown in the figure should fill the drum or chamber. Each layer should be separated by wire mesh. Thin layer of charcoal is used to absorb odor if any.
- 16. PVC Pipe filter This filter can be made using PVC pipe. The pipe is divided into three compartments by wire mesh. Each component should be filled with gravel and sand alternatively. A layer of charcoal could also be inserted between two of the layers. Sponge Filter It is a simple filter made from PVC drum having a layer of sponge in the middle of drum. It is the easiest and cheapest form filter, suitable for residential units. Types of Filters
- 17. By providing pipe water system with source (electric based) (a) Surface water (b) Deep wells Recharging strata's through rainwater harvesting methods (No. of villages of lower range concentration can be decreased) Storing rain water for drinking purpose (a) In areas where electricity is a problem (b) In areas where concentration is more (c) In areas where dependable source is not available How can the problem be minimized?
- 18. A reservoir Created with pond liner which lasts for over 50 years.
- 19. Rainwater harvesting for domestic use This can be used to generate potable water for drinking purposes, laundry and other household uses.
- 20. Use what you have Pre-existing depression being assessed for its ability to serve as a rainwater harvesting pond in support of drip irrigation for crop production.
- 21. Clear Drains This man is clearing a drain to have less debris in waterway.
- 22. Getting the rainwater harvesting pond ready Rainwater harvesting pond ready to be lined with pond liner.
- 23. Lining process The first layer of pond liner is being laid. Each piece is welded to the other to cover the full surface area of the pond.
- 24. Rainwater harvesting pond completed The next stage will be to install pipes to fill the tank.
- 25. Rainwater harvest system under construction This will use run-off water from building roof and transport the water in 10-inch PVC pipes to the pond that will in turn supply water through a drip irrigation system to support crop production.
- 26. Rainwater harvest pond being lined with water proof lining
- 27. Rainwater harvesting from run-off from roof – greenhouse structure
- 28. Used for crop production Rainwater harvest pond supporting shade-house crop production – tomatoes, sweet peppers, cucumbers. Same pond support the production of 2.2 acres of outfield vegetable mulched crop production – sweet pepper, tomato, cabbage, cauliflower.
- 29. We use what we sell Rainwater harvesting tank sold by Isratech Waterworks being used at Head Office in Manchester.
- 30. Use tanks for storage Black water storage tanks used to store water used in the pipe production process at the factories in Kendal, Manchester.
- 31. Conclusion In the past, farmers could almost predict rain patterns to determine when to plant their crops. But now, we scarcely know when we will be getting rain and still farmers are sticking to their usual patterns of planting thus they are losing crops. Since we can’t create water, let’s harvest it and use it when needed because every drop counts.
- 32. END THANK YOU
Editor's Notes
- The idea behind the process is simple. In short, Rainwater harvesting is a process or technique of collecting, filtering, storing and using rainwater for irrigation and for various other purposes. To reduce the consumption of groundwater, many people around the world are using rainwater harvesting systems. This practice has been around for thousands of years and has been growing at a rapid pace. Till today, rainwater is used as a primarily source of drinking water in several rural areas. The best thing about rainwater is that it is free from pollutants as well as salts, minerals, and other natural and man-made contaminants. In areas where there is excess rainfall, the surplus rainwater can be used recharge ground water through artificial recharge techniques. The roofs our homes are the best catchment areas, provided they are large enough to harvest daily water needs. Other than that, large bowls and tarps can also fulfill the function.
- The idea behind the process is simple. In short, Rainwater harvesting is a process or technique of collecting, filtering, storing and using rainwater for irrigation and for various other purposes. To reduce the consumption of groundwater, many people around the world are using rainwater harvesting systems. This practice has been around for thousands of years and has been growing at a rapid pace. Till today, rainwater is used as a primarily source of drinking water in several rural areas. The best thing about rainwater is that it is free from pollutants as well as salts, minerals, and other natural and man-made contaminants. In areas where there is excess rainfall, the surplus rainwater can be used recharge ground water through artificial recharge techniques. The roofs our homes are the best catchment areas, provided they are large enough to harvest daily water needs. Other than that, large bowls and tarps can also fulfill the function.
- The idea behind the process is simple. In short, Rainwater harvesting is a process or technique of collecting, filtering, storing and using rainwater for irrigation and for various other purposes. To reduce the consumption of groundwater, many people around the world are using rainwater harvesting systems. This practice has been around for thousands of years and has been growing at a rapid pace. Till today, rainwater is used as a primarily source of drinking water in several rural areas. The best thing about rainwater is that it is free from pollutants as well as salts, minerals, and other natural and man-made contaminants. In areas where there is excess rainfall, the surplus rainwater can be used recharge ground water through artificial recharge techniques. The roofs our homes are the best catchment areas, provided they are large enough to harvest daily water needs. Other than that, large bowls and tarps can also fulfill the function.
- The overall cost of their installation and operation is much lesser than that of water purifying or pumping systems. Maintenance requires little time and energy. The result is the collection of water that can be used in substantial ways even without purification. It also lessens the burden of soil erosion in a number of areas, allowing the land to thrive once again. In fact, it can also be stored in cisterns for use during times when water supplies are at an all time low. Rainwater is free from many chemicals found in ground water, making it suitable for irrigation and watering gardens. In fact, storing large reservoirs of harvested water is a great idea for areas where forest fires and bush fires are common during summer months. This has led to depletion of ground water which has gone to significant low level in some areas where there is huge water scarcity. It is unnecessary to use pure drinking water if all we need to use it for some other purpose rather than drinking.
- The reduced dependency means a reduced amount of stress on the dams and the elimination to expand upon them. Since we have such a limited supply of water available and it is very costly and timely to produce water through dams, the benefit found here is sure one that you will appreciate. The collected rainwater can be used around the home for laundry, washing dishes and more. This would prevent groundwater depletion and augment ground water table.
- There is always some skepticism regarding Roof Top Rainwater Harvesting since doubts are raised that rainwater may contaminate groundwater. There is remote possibility of this fear coming true if proper filter mechanism is not adopted. Secondly all care must be taken to see that underground sewer drains are not punctured and no leakage is taking place in close vicinity. This filter is very important in keeping the rainwater in the storage tank clean. The filter media should be cleaned daily after every rainfall event. Clogged filters prevent rainwater from easily entering the storage tank and the filter may overflow. The sand or gravel media should be taken out and washed before it is replaced in the filter.
- This filter can be made by PVC pipe of 1 to 1.20m in length. The diameter of the pipe depends on the area of the roof. A pipe with a diameter of 6” is enough for a 1500f2 roof and 8” diameter pipe should be used for roofs more than 1500f2. Both ends of the filter should have a reducer to connect inlet and outlet.