Rainwater Harvesting & Containment
Rainwater Harvesting & Containment
We need to recognize that the source of all water on earth is not the river, is not the underground aquifer, is not the lake, well or stream. Rain is the source of all water.
Introduction to Rainwater Harvesting
Rainwater harvesting was something the Greek and Romans used and was recorded all the way back to Southern Mesopotamia around 4500 B.C. They developed very complex systems for rainwater collection for agriculture and domestic uses. As towns began to grow and people started to demand more purified water the systems became more centralized and distributed through modern piping. This led to people thinking that fresh and clean water would always be available through tap water. Which meant that rainwater harvesting systems kinda dropped out of the picture. Now with increasing agriculture demands, a fast growing population, increased energy production, there is a growing awareness around supplementing our water supplies with rainwater systems.
The simple definition of rainwater harvesting: The capture, diversion, and storage of non-potable (not suitable drinking water for animals and humans) water for use at a later time.
Why Harvest Rainwater?
Water is life, and clean water means health.
The United Nations Educational, Scientific and Cultural Organization (UNESCO) predicts that by 2020 water shortages will be a serious worldwide problem. Most people are unaware of how much water they use by the products they consume. Lets look at the water footprint required for some common goods:
- 1 Cup of Tea – 9 Gallons of Water
- 1 Orange – 13 Gallons of Water
- 1 Apple – 18 Gallons of Water
- 1 – Egg – 36 Gallons of Water
- 1 Bag of Potato Chips – 49 Gallons of Water
- 1 Glass of Milk – 61 Gallons of Water
- 1 Cotton T-Shirt – 526 Gallons of Water
- 1 Hamburger – 632 Gallons of Water
- 1 Pair of Leather Shoes – 2,105 Gallons of Water
Take a hard look at the higher numbers; 526 gallons for a cotton t-shirt, 632 gallons for a hamburger, and worse of all 2,105 gallons for ONE pair of leather shoes.
Now lets talk about some of the benefits you can get from water conservation through collecting rain:
- Avoid strict city watering schedules
- Can save you money by reducing your water bills. Typically stored water costs $2-5 dollars a gallon.
- Use as a supplemental source to conserve your main water supply
- Maybe your only option if you’re in a remote area. This is why you see Alaskan homes using rainwater quite a bit.
- Help reduce erosion and control storm water to reduce the amount of pollution runoff which can include pesticides, fertilizers, spills and leaks which all can affect human, animal, and plant life.
- Can help achieve water sustainability to supply us the clean high quality water without stealing it from aquifers below ground robbing future generations water supply. Population growth in the next 50 years can be nearly 100% and will tax our water systems. Our water supply will be going down and population growing at an exponential rate.
- Reduces demands on municipal water supplies
- Reduces well water demands
- Raises awareness of water uses which leads to more efficient applications. When people can see the actual amount of water they use in a container they will be able to measure and lower the amount.
- Allows water to be slowly introduced back into aquifers instead of into storm drains.
- Helps reduce pollution by decreasing the amount of stormwater runoff that runs across surfaces such as roads, collecting oil, dirt, grease, and other contaminants until ending up in streams, creeks, and eventually the ocean
- “Designs that collect runoff and allow it to infiltrate the soil have the highest documented pollutant-removal efficiency, eliminating nearly all lead, zinc, and solids and more than 50% of total nitrogen and phosphorus. Ponds and wetlands, which allow contaminants to settle out of the water column or be broken down by sunlight and biological activity, can remove more than 70% of bacteria but are less effective for other pollutants.” ncbi.nlm.nih.gov.
You Might Not Know This
- Per year, the average household uses 66,175 gallons a water outdoors
- We’re experiencing extreme droughts in areas of the U.S.
- 70% of water used at homes is used outdoors
- An outdoor sprinkler can use up to 500 gallons of water every 2 hours
- 3,000 gallons of water are used weekly in the U.S. for landscape irrigation in households with a 10,000 sq. ft. lot
- A 2,000 sq. ft. roof can catch 1,250 gallons of rainwater from one inch of rainfall
- 30 inches of yearly rainfall on the above roof can create 41,000 gallons of reusable water
Current Status of the Environment
- Urban development is changing natural life giving streams into drains and sewers. Damaging the natural ecosystem health. (The urban stream syndrome)
- Worse the EPA states that almost 35% of estuary, 45% of lake acres, and 50% of our stream miles are in bad shape. Actually, below the standards of swimming and fishing.
- Greater than 50% of the waterborne disease outbreaks that have been documented since 1948 have been due to runoff. The Milwaukee Cryptosporidium outbreak happened after snowmelt and heavy spring rains. ncbi.nlm.nih.gov
- The EPA found that present stormwater systems are not able to handle our current and future stormwater management needs. Especially in urbanized areas. In Illinois alone the EPA found that 1,218 miles of streams are damaged by storm sewer discharges and urban runoff.
- A study in North Carolina looked at 208 large cisterns and rain barrels and found that rainwater harvesting systems were underutilized, which was caused by the publics perception of harvesting rainwater and faulty estimation of water usage. (www.sciencedirect.com)
Rainwater Harvesting Solutions
“So it is time to call for a new era of water conservation in our country. We need to start treating water like the most precious resource we have – wherever we live. We need to realize that the more we waste water, the less water is available for our neighbors, as well as the sh and wildlife in our local streams. Ultimately, wasting water hurts not only the environment, but our local economies, recreation opportunities and our quality of life.”
Rebecca Wodder, President– American Rivers
Two Types of Rainwater Harvesting:
- Active (complex) – Stores all or some of the water to be used later on. These systems are usually tank based and used for landscape water features, irrigation, wildlife, pet, livestock watering, and in-home use. Systems usually consist of catchment, conveyance, storage, treatment, and distribution.
- Passive (simple) – The landscape is used as storage and water is used immediately. A example of this is a rain garden, or green roof (EPA).
Active Rainwater System Components:
- Catchment surface – This is the most important part of the system. In-home applications usually always use the roof as a catchment surface. You should be aware that the contaminates of the roofing will need to be filtered depending on the intended use.
- Conveyance – This is more of a fancy word for directing water from catchments to storage containers. For example a roof conveyance system would use a gutter and downspout to direct water into a rain barrel (storage container).
- Storage – For when rainwater is needed. Most storage consists of rain barrels, underground tanks, above-ground tanks, and cisterns.
- Before Storage Treatment – Before the water is stored it needs to be screened and properly diverted. The goal is to make the water as clean as possible and remove large debris and critters from the water.
- After Storage Treatment – Most popular form of after storage treatment is UV (ultraviolet light). Other methods include reverse osmosis filtration, chlorination, ozonation and adsorption.
- Distribution – Bringing ware from its storage location to the point of use. In-home use usually requires a booster pump and pressure tank.
Active Rainwater Harvesting Supplies
Rain Barrels:View Rain Barrel Page
Rain barrels not only reduce the amount of runoff, but they also provide a great source of nutrient rich water for vegetable gardens or flowers. They’re a good first step into water conservation.
Passive Rainwater Harvesting
Xeriscaping is the practice of water wise landscaping that tries to minimize water consumption. Using xeriscaping you can help save water and benefit the environment and plants.
Tips for xeriscaping:
- Store rainwater to use during droughts, or dry weather
- Reuse gray water that has been collected from kitchen, laundry, or bathtub
- Practice smart watering habits including watering with drip irrigation and early in the day
- To help retain moisture us mulch
- Try to group plants together based on water needs
- Use drought tolerant, native plants
- Help improve soil quality with organic matter