John’s vision 12
However, over centuries, original water systems have been misused and damaged. We discharged pollutants into them, changed their direction to suit development needs – and more often than not physically obscured them from sight
Despite billions of dollars spent on costly hard solutions like sewers and treatment plants, the hard systems we have put in place are now an impediment to managing water as a vital ecological asset.
With increasingly extreme change, droughts and floods, a more erratic climate with more extremes, even the hard infrastructure is outdated. The size of water storage we have putm in place does not reflect the extremes that are likely to occur. Rainfall is becoming more intense, but less frequent; reservoirs are not sized to hold the extra water, and downstream flooding is more likely to occur. We have to re-visit thousands of storage faclities and reassess their design paramaters to see how prooof they are against climate change.
We’ve also created an urban landscape that makes pollution worse, not better: a preference for impervious over porous surfaces; fast “hard” conveyance infrastructure rather than “softer” approaches like ponds and vegetation; and rigid stream channelization instead of natural stream courses, and development in floodplains.
Traditonally, the water industry has tended to focus its innovation on the search for technological improvements - such as, these days, advances in membranes. Resources have been allocated to projects that add new functionality to existing engineered urban systems.
But hard, machine-model approach to infrastructure is longer appropriate for water management.
The new paradigm in water management – so-called Water Sensitive Urban Design – features a return to the hydrology of a city as it was before the conveyor system metaphor took hold.
The new approach integrates watershed and water cycle management into urban planning and design.
The focus shifts from high entropy engineered solutiuons, such as reservoirs and sewer networks, to ecological systems that give priority to rain gardens, surface wetlands, restored ponds and daylighted streams.
Rainwater, especially, is now treated as a resource. High efficiency decentralised treatment plants can provide reclaimed water for re-use in buildings toilets heat recovery and cooling, irrigation,
Starting right now, urban landscape and drainage systems need to be designed to mimic the natural hydrological cycle – recharging aquifers with reclaimed rainwater, and returning the base and flood flows of streams to their predevelopment levels.
So called soft water engineering means controlling these waters as close to their sources as possible. At a small scale, therefore, the introduction of Sustainable Urban Drainage Systems (SUDS) means we need to re-design roofs, pavements, streets and parking spaces.