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===Rainwater Catchment basics=== | ===Rainwater Catchment basics=== | ||
The purpose of a rainwater catchment is to collect rainwater and store it for later use. Using rainwater for watering the garden will save clean potable water from being wasted when resources such as rain water are available for free. To maximize the amount of rain captured, there are many variables to consider. The | The purpose of a rainwater catchment is to collect rainwater and store it for later use. Using rainwater for watering the garden will save clean potable water from being wasted when resources such as rain water are available for free. To maximize the amount of rain captured, there are many variables to consider. The ideal surface to collect rainwater is a metal roof, however nearly any roof can serve as a collection surface. The square footage of the catchment surface is only as big as the foot print of your house, garage or (in my case) the green house. Although the surface area of a sloped roof is greater that the foot print of the house, the amount of rain that falls on the foot is not affected by the slope. Water that is one inch deep and one foot square equals exactly .6233 gallons. However, we subtract approximately 20% which is lost due to evaporation, leaks, plugged gutters, etc. So the number is rounded down. In a one inch rain you can catch approximately 550 gallons per 1000 square feet of collection surface. You can calculate the amount of rain you can catch by using a simple calculation by dividing the square feet of the total catchment area by 1000 and multiply that number by 550 to determine gallons collected per one inch of rain. Multiply that by the average annual rainfall in your area and you will the the amount of water you can probably collect<ref>Banks, Suzy, and Richard Heinichen. Rainwater collection for the mechanically challenged. 2nd rev. ed. Dripping Springs, Tex.: Tank Town Pub., 2004.</ref> | ||
===Rainwater Catchment concerns=== | ===Rainwater Catchment concerns=== | ||
Revision as of 01:31, 19 February 2012
Introduction
The global population has reached 7 billion people and continues to grow steadily. With the huge growth in our population, human beings have become more aware of the value of our limited resources. Many people are looking towards ways of sustainable living and preserving natural resources in order to survive in this rapidly growing population. One of the more abundant natural resource in Humboldt County is rainwater. This ecological awareness and the search for sustainabiity has lead me to designing a small rainwater catchment system for my greenhouse. Rainwater harvesting or collecting refers to the collection and storage of rainwater. Rainwater is usually collected from rooftops and diverted into a storage tank for later usage that includes but am not limited to watering gardens and landscaping, washing cars, washing laundry to flushing toilets.
Background
I have always been interested in off grid living while trying to maintain a sustainable lifestyle. We have implemented some of these ideas in the 2 years we have lived here- ranging from raising hens for eggs, organic gardening to composting. We have also built a greenhouse using salvaged windows, doors and various recycled building materials. The greenhouse is located in our backyard in Manila, CA. The greenhouse rainwater catchment system seems to be a natural next step toward self-sufficiency and natural resource preservation. We decided that utilizing the knowledge and information gained from the spring 2012 Engineering 305 projects would be the perfect momentum we needed to implement this system. This project will begin in January 2012 and will be completed in May 2012.
Opportunity Statement
The objective of this project is to install a small rainwater catchment system in the 10x12 greenhouse my husband and I have built in our backyard- located in Manila, CA. We hope to use as much recycled and salvaged building material as we possibly can with this project.
| Criteria | Constraint | Weight |
|---|---|---|
| System Efficiency | The installed system catches 80% of rainfall runoff from the greenhouse. | 10 |
| Budget | Less than $200. | 9 |
| Maintenance | Less than 1 hour of work per week. | 8 |
| Functionality | They system has to work and be able to pump and transport water into greenhouse and garden and for irrigation use. | 8 |
| Educational | The system will serve as a small-scale example of rainwater harvesting. | 7 |
| Durability | Lifespan of system = At least 5 years. | 6 |
| Appropriate Use of Material | To use as much recycled or salvaged material as possible in building this system. | 5 |
| Water Potability | Clean and sanitary enough for irrigation use. | 5 |
Literature Review
This is a review of the available literature pertinent to building a rainwater catchment system.
Rainwater Catchment basics
The purpose of a rainwater catchment is to collect rainwater and store it for later use. Using rainwater for watering the garden will save clean potable water from being wasted when resources such as rain water are available for free. To maximize the amount of rain captured, there are many variables to consider. The ideal surface to collect rainwater is a metal roof, however nearly any roof can serve as a collection surface. The square footage of the catchment surface is only as big as the foot print of your house, garage or (in my case) the green house. Although the surface area of a sloped roof is greater that the foot print of the house, the amount of rain that falls on the foot is not affected by the slope. Water that is one inch deep and one foot square equals exactly .6233 gallons. However, we subtract approximately 20% which is lost due to evaporation, leaks, plugged gutters, etc. So the number is rounded down. In a one inch rain you can catch approximately 550 gallons per 1000 square feet of collection surface. You can calculate the amount of rain you can catch by using a simple calculation by dividing the square feet of the total catchment area by 1000 and multiply that number by 550 to determine gallons collected per one inch of rain. Multiply that by the average annual rainfall in your area and you will the the amount of water you can probably collect[1]
Rainwater Catchment concerns
Concerns regarding rain water catchment system deal with a wide variety of issues ranging from the location of the water storage tank to the collection and filtration process. This books covers various concern from rain collection in dry lands to landscaping to maximize rain collection. [2]
Peer Reviewed Article
Indirect lack of water can be defined as the case where water-resources are sufficient to meet anthropogenic demands, but available water resources may be allocated for other uses or the resources can be undesirable for political reasons. Such indirect deficit occurs because water is needed to sustain ecosystems or because the water supply is based on politically undesirable water imports.[3]
Several literature suggested that I follow a thought out plan when building a rain catchment system. The planning process begins with a long and thoughtful observaton and begin the project at the top or the high point of the watershed and work my way down. It also suggested that I start small and simple. Planning for an overflow is a must in building rainwater collection as well as a continuous reassessment of the system. [4]
These are some web sites I fund that contained useful information regarding rainwater collection.
[5]
[6]
[7]
References
- ↑ Banks, Suzy, and Richard Heinichen. Rainwater collection for the mechanically challenged. 2nd rev. ed. Dripping Springs, Tex.: Tank Town Pub., 2004.
- ↑ Lancaster, Brad, and Joe Marshall. Rainwater harvesting for drylands. Tucson, AZ: Rainsource Press, 2006.
- ↑ 2011. Increasing Urban Water Self-sufficiency: New Era, New Challenges. Journal of Environmental Management. 92, no. 1: 185.
- ↑ Pacey, Arnold, and Adrian Cullis. 1986. Rainwater Harvesting: The Collection of Rainfall and Run-off in Rural Areas. London: Intermediate Technology Publications.
- ↑ http://www.rainwaterconnection.com/rainwater_harvesting/basic_components.htm
- ↑ http://www.rainbarrelguide.com/rainwater-harvesting-systems/
- ↑ http://www.harvesth2o.com