A review article published in the Environmental Science and Technology journal calls for better storm run-off management in California, advising the adoption of ‘low impact development technologies’ such as green roofs and rainwater tanks to assist rainfall drainage, minimising the risk of mudslides and flooding.
The review article was based upon research undertaken in drought-stricken south eastern Australia, and was released just recently this year during October, not long after water run-off caused mudslides and flash flooding in southern California.
The article was compiled by a group of water management professionals including urban planners and engineers from numerous Australian and California universities, plus Orange County Public Works water managers, as well as an engineering consulting firm.
Quite simply the natural water system in California is struggling to cope under the pressures from continual, unending modern construction.
Today, modern infrastructure blankets the cities of California, the endless, overflowing sprawls are filled with roads, pavements, buildings, parking lots and other man-made structures. With so much concrete, glass & steel covering the soil of California, the risk of ever worsening urban flooding caused by rainwater run-off blockages are an escalating problem facing major cities, posing a very real threat to lives, property and the eco-system.
These blockages redirect the water run-off into rivers and streams causing:
1. Flooding & mudslides
2. Soil erosion
3. Long-term ecosystem damage
4. Property damage
5. Deaths and injury
6. Flooding also brings a whole host of contaminants into cities such as diseases, pollutants and sediment. These can cause imbalances in the natural chemistry of rivers and streams and also lead to rising water temperatures which is harmful to wildlife and plants inhabiting the rivers and streams all the way along, down to the ocean.
“The massive volumes and pollutants associated with stormwater runoff are a deadly one-two punch for streams and lead to a condition known as ‘urban stream syndrome,’” explained Asal Askarizadeh, the paper’s lead author & UC Irvine graduate student in civil and environmental engineering.
Asal Askarizadeh and his team believe the current centralised infrastructure, city planning model favoured worldwide is failing when it comes to effectively managing storm water run-off.
His team propose the best solution is to catch as much rainwater run-off as possible and re-use it using a ‘distributed infrastructure’ model which would include green roofs and water tanks complementing the current centralised infrastructure (not replacing it).
“The reason is that in order to protect receiving waters and streams, we need to capture the runoff as close to where it’s generated, for example your home, as possible,” explained Brett Sanders, co-author & chair of the Department of Civil and Environmental Engineering at UC Irvine.
Individuals and state/local governments would need to change their thinking on how they handle urban water run-off management. Certain legislation would need amending.
“We expect the government to manage our water supply completely, and in some places, it’s even illegal to harvest rainwater locally. Laws and habits are going to have to change if we are to adapt to new climate and urban realities,” said David Feldman, co-author & co-chair of the Department of Planning, Policy, and Design at UC Irvine.