Flood Prevention Plans
Risa Kimura
Risa Kimura
Image: Coal-fueled power plant
For over 50 years, scientists had been discussing the effects of human induced climate change, estimating that this was a problem that the world would face by the year 2050. However, the gravity of global warming has now been appearing more rapidly than we had anticipated. In fact, the global mean temperature for the past eight years have been recorded as the highest since the 1850s. The increase in temperatures has caused both the glaciers to melt and seawater to expand, ultimately resulting in rising sea levels. Rise in water level amplifies the intensity and frequency of deadly storms. Cities like Manhattan in particular, face the threat of losing key areas such as lower Manhattan due to flooding.
Looking at data in New York, rise in sea levels measure out to approximately 9” since the 1950s, with an alarming acceleration over the last 10 years. At the current rate of increasing sea levels, New York faces moderate flooding to occur 10 times as often, and sea levels to rise up to 12” by the year 2050. By 2055, Manhattan is predicted to confront sea level rise of up to 2 ft.These statistics highlight the importance of creating more stringent resiliency plans.
Image: Sea Level RIse
New York has already begun preparations for combatting the effects of sea level rise through a variety of resiliency plans for flood prevention.
East Side Coastal Resiliency project is a design using a “combination of raised parkland, flood-walls, floodgates, and infrastructure improvements” that are imbedded seamlessly into the surrounding landscape. The flood-walls utilize both swing and roller gates to quickly close the area off from water entering from over-flooding in the Hudson river.
Many restaurants are also partaking in flood prevention measures by donating their oyster shells. Living Breakwaters utilizes the shells of empty oysters to make an oyster reef that will then promote the growth of more reefs. By reviving reefs, the city will be more resilient towards incoming crashing waves.
In neighboring areas such as New Jersey, officials plan to put restrictions on new developments in flood-prone areas. Restricting further developments in these areas are key to minimizing future infrastructure damages. In the case of New Jersey, instead of relying on flood maps and rainfall projection maps, they have sought to create policy changes through the anticipation of the effects that climate change impacts will have on the future.
Left - East Side Coastal Resiliency, rendering by BIG
Middle - Oyster Project, photograph by Ted Shaffrey
Right - Development Restrictions
Although the abovementioned projects will dramatically improve flood threats due to rising sea levels, we must also consider threats posed by heavy rain.
Diagram of a sponge city
In conjunction with current flood prevention measures, it is also imperative to start aggressively converting New York into more of a sponge city. A sponge city is a type of urban design that absorbs rainwater until it is slowly filtered through drainage systems. The benefit of a sponge city is that it can reduce flood related damages to infrastructure, while also releasing stored water during times of drought. This full-scale conversion is the necessary next step, since a sponge city shows great resiliency towards floods from heavy storms while also combatting global warming, when compared to the average urban city.
Currently, Manhattan is implementing measures to convert itself to a sponge city, Green roofs which currently cover “less than 0.1% of New York City’s” buildings is a great tool towards the transition for a sponge city. However, green roofs are not only costly to implement, but also too heavy for most roofs to support. Current laws pertaining green roofs state that “all new buildings and alterations of existing buildings where the entire existing roof deck or roof assembly is replaced must provide a sustainable roofing zone covering 100% of the roof”. This gives two options, either implementing a green roof or solar panels. However, this law should be revised to state that new developments must have a combination of green roofs and solar panels. In addition, since solar panels are more effective for high rise buildings, these structures would be suggested to have more solar panels than green roofs. The combination of these two will help decrease energy consumption, and limit the heat island effect that cities face during warmer seasons.
Alongside the re-evaluation of the sustainable rooftop laws, all combined sewer systems should be converted into a separate sewer system. A combined sewer system is problematic because it collects both wastewater and rainwater at the same time. During times of heavy rain, this type of collection method can make this system over exceed in capacity. When it exceeds, it “discharges excess [untreated] wastewater directly to nearby streams, rivers, or other water bodies”. The combination of untreated wastewater, debris, and other toxic materials along with the storm water is a source of pollution to these nearby water bodies. The separate sewer system is also a key element of sponge cities. This is because, in the case of overflow with a sponge city, water will still be filtered into the drainage system and sewer much slower than a non-sponge city. The steadier absorption of rain water will allow more time for the sewage plants to treat the water and remove any debris before it re-enters a nearby water body.
Finally, the use of more developments on various levels of land, particularly around areas that border any water body, is a useful added security towards the flood prevention systems that are currently underway.
Although flood protection barriers are essential toward creating a more resilient New York for the future, having a sponge city will ensure that New York will no longer be threatened by flood related deaths, and flood related building/ infrastructure damages.
Sources:
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