Complex Water Harvesting

Have you tried simple water harvesting and decided you would like to take it to the next level?  The next step is called complex water harvesting and it involves collecting and storing rain water for future use.  I have a friend who lives in Hawaii and has been harvesting and storing water for years.  He says most everyone there does.  It rains every morning and the collected water goes into a small above ground pool.  It is from this pool of water that most of their water needs are met.

Complex water harvesting systems can be as simple as running your rain water into an above ground pool or a little more elaborate using a more typical storage tank.  The idea with complex systems is to provide water for your outdoor needs between rains.  A storage tank of one form or another is needed to do this.  Also needed are the pipes to get the water into and out of the tank.

In places like Arizona, where I live, the rain falls mainly during our two rainy seasons with long periods of no rain in between.  When it does rain, it really rains, usually far more rain at one time than our plants can use.  Once the ground is saturated the remainder of the rain is, for all practical purposes, wasted.  A complex water harvesting system can store this extra water to be used during dry periods, when the plants need the water most.

When deciding how big of storage tank you need there are several considerations.  The first one usually asked is if the water savings will pay for the cost of the tank and installation.  Eventually it will but it may take a while, depending on the amount of water collected and your normal watering needs.  The main goal should be to take care of as much of your outdoor water needs as possible with this stored water.  You might base the size of your storage on the amount of water you plan to use or you could base your landscaping on the amount of water you plan to collect.  There are many ways to think about water storage depending on how green you want to be.

The components of a complex water harvesting system are the catchment areas, conveyance systems, storage and distribution systems.  The amount of water collected is called the yield.  The catchment area is the place where the water is collected.  This is usually a roof but could be any hard surface like a parking lot or driveway.  The conveyance system is the means of getting the water from the catchment area to the storage.  When collecting water from a roof the conveyance is usually a gutter and downspout system.

Storage containers can be above ground or in ground.  They can be made from materials like wood, metal, fiberglass and polyethylene.  Some of the items that could be used for water storage are regular water storage tanks, large garbage cans, 55-gallon steel or plastic drums, barrels, stock tanks, fiberglass fishponds and, of course, above ground pools.  Whatever you decide to use be sure it remains covered and kid proof.  It should also be labeled as non drinking water.  Water storage containers can be obtained for as little as a hundred dollars up to several thousand dollars.

The distribution system will take the water from the tank and distribute it to your plants.  This can be as simple as a garden hose, or as complex as underground irrigation pipes.  Water flow can be controlled by gate valves, ball valves and diverters.  Depending on the design of your system, it might be completely gravity fed, or you might need a pump to move the water.  Submersible pumps can be used when needed.  If you are pushing the water uphill, or pushing the water through a drip system, a pump will be needed.

Water harvesting can apply to your indoor water in addition to the outside rain water.  Gray water can be used to water your plants so long as you are using the proper soaps and detergents.  Designing gray water use into the design of a new "green home" is very common.  It is also possible to re-plumb an existing home so that a portion of your water drains onto your plants, lawns and gardens.

Harvest water, conserve water, and just maybe, there will enough to go around.