Brad Lancaster on Rainwater Harvesting - Day 1 of IPC10: Slow, Spread, Sink.
“What is the story of your place?” and “What is the story of its water?”Brad Lancaster began to tell two tales of water — a degenerative story and a regenerative story.
A Degenerative Story: “The Hydrophobic Society”
Showing images of urban landscapes designed to hasten the movement of water from those landscapes, Brad suggested that these landscapes were indicators of a “hydrophobic society.”
Not only is water wasted by this hydrophobia but the risk of flooding is increased 10 fold when paved, concreted and otherwise sealed areas feed the ‘dehydration infrastructure’ designed to solved the ‘problem’ of water inundation in drylands.
“Distance is energy”The result of seeing rainwater as a problem which must be drained is waste and, therefore, expense. More rain falls on Brad’s home, Tucson, Arizona, than is necessary for drinking, washing, food production and industry — all of Tucson’s water needs. Yet the pumping and transportation of water from the Colorado river is the largest consumer of electricity and the largest single source producer of carbon. Waste creates expense — “distance is energy.”
A Regenerative Story: “Run off” to “run on” which is “right on.”
In Tucson 3,000,000 l of water falls on each kilometer of sealed road each year. Outside of their house, Brad and his brother began to use some of this water to irrigate native mesquite trees on their verge. The kerb was cut to allow the water from the road to ‘run on’ into the mulched basins in which the trees were then able to grow. Sufficient water falls on the roads of Tucson to passively irrigate a mesquite tree in a mulched basin every 8m. Recently, these mulched basins have been found to host a soil ecology approaching that of an established forest in comparison to the surrounding, relatively dead and degraded soils. Where mesquites have been grown in this way, local people have been able to earn $25 an hour picking mesquite pods to be processed into a naturally sweet flour and made into many kinds of food for sale. This is one example of the creation of a regenerative system which turns ‘run off’ into ‘run on’ while increasing biodiversity, growing shade, food, community and livelihood. These basins are examples of ‘infiltration infrastructure’ — ‘rehydration infrastructure.’
“Show the flow”
Mulched basins and other water harvesting earthworks which are a part of rehydration infrastructure not only catch rainwater where it falls but are also able to receive greywater. Brad prefers to keep the greywater outlet pipe above the mulch level to prevent it being blocked up by roots and to ‘show the flow.’ I know that washing day is an exciting time at my house. There is something special about seeing this productive use of water which would otherwise go to waste.
“Plant the rain and the plants will plant themselves.”
Brad emphasised that we must:
“Slow. Spread. Sink!” rather than “Pave. Pipe. Pollute.”By slowing water and allowing it to spead out and infiltrate, the earth responds with growth. Native and productive trees planted with an awareness of the the rainwater harvesting budget of a site can provide shade, food, biodiversity and many other benefits. Water is the beginning of the creation of regenerateive landscapes which provide many yields while improving ecological health.
Brad closed an inspiring talk with the suggestion that we all have a role to play in the story of water in our landscapes. We can choose the story and we can choose the role. Degenerative or regenerative? Not a hard choice, really.