APRIL 2024CONSTRUCTIONTECHREVIEW.COM8IN MYOPINIONThe year 2021 broke many records with the number of natural disasters occurring in the United States. In New York City, Tropical Storm Henri deluged the city on August 21st with a record-breaking rainfall rate of 1.94 inches in an hour, with total rainfall amounts of over 8 inches in 36 hours. Then, only 11 days later on September 1st, that record was also broken by Hurricane Ida submerging the city in 3.15 inches of rainfall in an hour, totaling 8.13 inches of rainfall in one night ­ and also tragically ending the lives of 45 people in New York and New Jersey. Clearly, new solutions are urgently needed to combat these flood-ing events that are becoming more frequent, intense, and dangerous.Episodes of flash flooding occur when large amounts of rain suddenly fall on mostly impervious areas in a short period of time. With minimal places for the water to go for absorption into the soil and back into recharging the local ground water tables, the stormwater is instead pouring into subway stairwells and platforms, infiltrating into the basements of homes and businesses, and causing polluted overflows of combined stormwater and raw sewage being directly dumped out into the surrounding waterways (CSOs). While city agencies have adopted integrated water resource management approaches for some years now by incorporating green roofs and green infrastructure into overall strategy and area development, the pace and By Anna Fu, Vice President of Construction/Sustainability, SIMCO Engineeringresults and have been far too little too late in the face of these intensified storms currently inundating the city. A lot more, and better, has got to be done -- if cities like New York are to adapt to and overcome some of the disastrous effects of climate change. Perhaps one of the simplest ways to effectuate a needed paradigm shift is to go back to basics. If this is a problem of simply too much water at one place at a time, what can be done to reduce the amount of water? One solution can be from realizing that it doesn't make complete sense to bring in fresh potable water from over a hundred miles away and using most of it in households just to literally flush down the toilet. Instead, rainwater (and grey water) can be captured, stored, and treated to tertiary standards onsite to be used for this very purpose, rather than diverting it miles away into an energy intensive treatment plant to then drain and discard out to surrounding waterways. There are about 1 million buildings in the city, representing an average of 40,000 acres of rooftop space. With an average rain fall of 46 inches per year, about 49.9 billion gallons of water per year can potentially be captured on just rooftops, treated, and used onsite ­ amounting to close to 10 percent of the city's total water demand (not yet taking into account interferences, runoff coefficients etc.). Further, this "water budget" likewise reduces the corresponding stormwater amount, and can help drastically reduce the average 20 billion gallons of untreated raw sewage and polluted runoff from being dumped out at the shorelines throughout the five boroughs.WHY SUSTAINABLE STORMWATER MANAGEMENT MATTERS
< Page 7 | Page 9 >