Diverted rain perfectly legal

Ceres Environmental Park rainwater harvesting tank, Melbourne, AU

Ceres Environmental Park rainwater harvesting tank, Melbourne, AU (ceres.org.au.)

Becky Elder

“Irrigated plants become dependent on people…”  John Cruickshank, permaculturist

People often say that it is illegal to collect rainwater in Colorado. After all, the state brochure on the subject says in no uncertain terms, “It is illegal to divert rainwater falling on your property expressly for a certain use unless you have a very old water right.”

Colorado residents should understand that water rights in this state are unique compared to other parts of the country. Rainwater is governed by the constitution, state statutes and case law.

The use of water in Colorado and other western states is governed by what is known as the “prior appropriation” doctrine. This allocation system controls who uses how much water, the types of uses allowed, and when those waters can be used.

A simplified way to explain this system is “first in time, first in right.”

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An appropriation is made when an individual physically takes water from a stream or well (when legally available) and puts that water to beneficial use. The first person to appropriate water and apply that water was awarded the right to use that water, the first right to that water within a particular stream system.  Their senior water right must be satisfied before any other water rights are filled.

Most, if not all, of our stream and river systems have been over-appropriated, meaning that at some or all times of the year, there will not be enough water in that stream system to satisfy all vested water rights.

These laws were created in the mid-1800s by mining companies and bankers without the help of farmers or hydrologists. The climate was delivering much more water back then. The system was set up with the concept that all rain that fell made its way into the surface systems of streams and rivers.

A 2007 study by the Colorado Water Conservation Board and Douglas County determined that only 3 percent of rain actually reached a stream.

Having said that, putting the water from above into the soil beneath our feet is the best way to harvest rainwater legally. There is much one can do by simply creating landscapes that capture the free flow and designing our houses’ water sheds to put rainwater into the soil and not off into the gutters.

Rainwater “harvesting” is perfectly legal. Rain can be diverted from impermeable surfaces to be retained in the soil and put to use for lawn and garden irrigation.

Rainwater can be legally harvested from rooftops, concrete patios, driveways and other impervious surfaces. Buildings and landscapes can be designed to maximize the amount of catchment area, thereby increasing rainwater harvesting possibilities.

Directing rainfall to plants located at low points is the simplest rainwater harvesting system. In this system, the falling rain flows to areas with vegetation.

Inexpensive rainwater systems commonly make use of above-ground containers such as a barrel or plastic tank with a lid to reduce evaporation and bar access for mosquito breeding.

Any container capable of holding rain dripping from roof or patio can be used as a rainwater harvesting system, moving that water to where it can be useful in landscaping.

Rainfall in urban and industrialized areas may contain various impurities absorbed from the atmosphere, including arsenic and mercury. In Colorado, rain is infrequent, but rainwater quality is generally good.

However, the infrequency of rainfall results in accumulation of bird and animal droppings, dust and other impurities on rooftops between rains. These impurities may occur in high concentrations in rooftop runoff when it does rain.

The best strategy is to filter and screen out contaminants before they enter the barrel.  Dirty containers may become a health hazard or a breeding ground for mosquitoes and other pests.

A “first-flush” devices ensure a certain degree of water quality in harvested rainwater.  The first several gallons of runoff from a gutter, roof, or other surface are likely to contain various impurities as mentioned.  This allows the barrel water to be cleaner and without obstructions for free flowing.

The “flush” water can still go on the landscape as the soil itself, is the best water cleaner on the planet!

Many first-flush systems have a simple design. Such devices include tipping buckets that dump the “dirty” water when it reaches a certain level.

In our urban landscapes, much of the God-given rain is allowed to rush off our landscapes and into greater system, creating storm water flooding.  Swaling is an ancient method of earth working, forgotten by modern man, that captures rainwater run off and allows it to percolate into the soil.

The soil will recharge underground water tables, slowly feed streams, and help store water for urban forests.

Swales are simple ditches running on contour to capture runoff long enough to infiltrate the soil.  They are long, level excavations and can vary in width and length.

Flat ground can also have depressions dug to collect more water in one place. Rain gardens work with this technique.

Dig your swales with the soil piled on the down-hill side. Don’t want to dig? You can arrange rocks or lay logs horizontally to slow the water running down and allow more to be absorbed in the soil.

Arid land swales have greater distance between swale than wet climates, the more rain potential, the more swales you need. Steep slopes require more swales closer together as the slope pushes the water faster.

Swales are built to capture the big water, so double the size of your swale by either widening, deepening, or lengthening it.  Start your earthworks at the top of your personal watershed – the highest ground – and work your way down.

Colorado native plants already know about slope, runoff and erosion, not to mention drought.  They can help…salvias, sages, pussy toes, rockcress, kinnikinnik and the native grasses, as well as native shrubs.

Most of us remember playing in the rain when we were children, making dams, diversions and creating river systems on miniature.  Earthworks is that … for grownups!

Becky Elder is a member of the PPJPC Green Hall of Fame and Green Cities Coalition Steering Committee. She also runs an organic and permaculture gardening company, Blue Planet Earthscapes.

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