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Feb 18, 2023

CITY STORM WATER DRAINAGE SYSTEM -Revisiting fundamentals

Please visit my web page "Urban Tenets" at https://urbantenets.nl/

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SITUATION

No matter how well you plan Storm Water Drainage System, it often fails as it has so many missed variables, scores of design and operational dependencies, aging infrastructure and multitude of agencies to put blame on, later on.

TREND

Storm water and Urban Flood used to be two different things, but their boundaries have started to get blurred, as rainfall events are getting more unpredictable and severe due to climate change and as normal rainfall events have frequently started causing sticky urban floods that is not easily dissipated.

POSSIBLE MEANS TO DEAL WITH SITUATION

There are only couple of ways you can deal with storm water inundation and urban flood events, i.e. either move the city elsewhere OR tame the nature through uphill dams and artificial mega wetlands at outskirts OR brace the city with flood barriers OR capture and store part of runoff water allowing as much water to percolate if water table permits OR make way for water and allow storm water and floods to pass through city while assuring minimum impact and damage.

CHALLENGES

Temporal rainfall data of whatever time period used in modeling is primarily historic data, there is no consideration for future rainfall event modeling considering climate change, increasingly aggressive weather events being witnessed every passing year.

Historic Flood data doesn't consider cause and effect of flood due to slow or sometimes radical temporal change in built form and landscape of city.

Expanding cities, increasing paved areas, shrinking greens and disappearing urban waterbodies are changing the overall runoff coefficient of city converting normal rainfall event into disastrous situations and unmanaged events.

OPTIMAL SOLUTION

Instead or in addition to regular storm water network if you plan or redevelop your city as well as design buildings to allow periodic Inundation and water retention and absorption, that will be less destructive and less overwhelming then flash floods due to heavy downpour and in case of actual flood events.

It's important to keep reiterating that Multicriteria based assessment, design and scenario modeling is of utmost importance for planning any urban core infrastructure, be it SWD, SWM, Water Supply or Power Distribution.

#urbanplanning #smartcity #stormwatermanagement #sustainability #future #water #flood #swale #LID #zerowaste #urban #cityplanning #townplnaning #municipality #municipalcorporation

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