Harvest the Rain A Presentation by the Vlahi

Harvest the Rain A Presentation by the Vlahi Nature School This project was financed in part by USAID

What is Rainwater Harvesting?

“The collection…

…storage…

…and reuse of rainwater. ” 1

Why harvest the rain?

• Environmental Benefits – – Prevents runoff, erosion and flooding Saves energy Local, sustainable and clean water source Reduces pressure on ecosystems and watersheds if managed properly

• Economic Benefits – – Free water source Save on energy costs Reduces labor need Increases crop productivity, which in turn reduces poverty • Other Benefits – – – 105, 000 liter collection system in Texas 2 Simple, but very effective Ideal for rural, dry areas “Rain water harvesting… is the most economical and surest way of providing water for drinking and sanitation even in the remotest areas. ” – UNEP – Resource independence reduces the potential for conflict

How to Harvest Rainwater? • Rainwater harvesting is an ancient practice. Systems can range from extremely simple and inexpensive to highly complex and costly. • It all depends on your available resources, your goals and, most of all, the rain!

Simple landscape systems 3 • Gravity based • No storage device • Harvesting is done by a simple trench and landscape design • Planned slope and landscape architecture • No storage; distribution is done by the lot itself

Complex Landscape System 4 • Gutters installed to concentrate and direct flow • Rain is stored in a cistern for later use • Stored water is distributed as needed to plants via irrigation hoses

Key Components of Complex Landscape Systems • Catchment Surface (typically a roof) • Gutters • First flush diversion • Filters • Cistern or reservoir (with proper foundation • • insulation) Irrigation or other outlet pipes Overflow pipe

Reservoir Filters for debris / insects First flush diversion Concrete foundation Insulation Irrigation hose

First Flush Detail • Water comes down from the roof • The first rain collected is dirty from washing the roof so it goes to the down pipe, not the reservoir. • Once the down pipe is filled, water diverts to the reservoir, ensuring that the dirty rainwater is not stored • Diversion is mostly self cleaning via a drip on the T-outlet • Periodic full cleaning is possible by removing a plug at the bottom

Potable Rainwater System • Potable water outlet • Ultraviolet Lamp • 5 micron filter; 3 micron charcoal-activated filter • On Demand Pump • Non-potable Rainwater 5

Considerations for 6 System Design: • This map shows the proper • • • process for designing rainwater harvesting First, you must consider your needs and alternatives Second, you must determine your available resources Third, you must reconcile your needs and resources to design your system Then, and only then, should you begin implementation Generally, rainwater harvesting is not a “silver bullet, ” but rather a source complementing other water supplies.

Conclusion: • Rainwater harvesting can be a great solution to • many water resource problems. However, to maximize the benefits of rainwater harvesting, you must think about your situation and whether this technology is appropriate for you. For more information, please see our manual on the basics of rainwater harvesting for drip irrigation and the resources on the next page.

Sources 1. 2. 3. 4. 5. 6. 7. http: //www. nkba. org/green/glossary. aspx Texas Water Development Board. “The Texas Manual on Rainwater Harvesting – Third Edition. ” Austin, Texas. 2005. http: //www. twdb. state. tx. us/publications/reports/Rainwater. Harvesting. Ma nual_3 rdedition. pdf Worm, Janet and Van Hattum, Tim. “Agrodok 43: Rainwater Harvesting for Domestic Use. ” Agromisa Foundation and CTA, Wageningen, The Netherlands: 2006. Accessed at: http: //www. agromisa. org/agrodoks/Agromisa-AD-43 -E. pdf Images from: Waterfall, Patricia H. “Harvesting Rainwater for Landscape Use. ” University of Arizona Cooperative Extension. 2006. http: //www. azwater. gov/dwr/Conservation/files/Harvesting_Rainwater. pd f Image from: Waterfall, 2006. Image from: The Rainwater Observer. “Rainwater System Installation, Part 2. ” http: //www. rainwatercollecting. com/blog/? p=256. Accessed on: 02. 07. 2009 Texas Water Development Board, 2005.