I got a chance to listen to a talk, sponsored by AIA New York, Center for Architecture. There speakers represented from 4 cities: Copenhagen, Rotterdam, New Orleans and New York. These cities have started to think and re-design cities during heavy rains and floods.
Things I learned about Copenhagen:
This city has already started to design for the 100-year storm. In 2011, there was a major rain, that collected 150mm of water in 2 hours. The city wasn’t prepared for that.
The city looked into natural flow water, using the existing city infrastructure. Then, the city planned man-made waterways, to help move water to the harbor.
They created 4 types of typologies:
- Cloudburst roads: Cloudburst roads are used to channel and direct cloudburst water. These streets can be formed with a V-shaped profile and raised herbs to ensure water will flow in the middle of the road, away from the buildings.
- Central retention: Central retention areas are proposed in the squares and park where it is possible to delay stormwater so that cloudburst roads can be established in smaller dimensions. The central retention elements can be, for example, open depressions in the parkland or lowered seating areas
- Green streets are proposed as an upstream connection to all cloudburst roads. The green streets should be established with a combination of small-scale channels and stormwater planters or permeable paving. Stormwater should be collected, delayed and then channeled towards the cloudburst roads.
- Local retention: Local retention is small scale solutions for individual plots or communal areas. These areas deal with stormwater directly where it lands, typically in local risk areas are low. The solutions are small scales such as rain gardens and storm water collection units. For example, The lake is lowered, so it can retain more water during a storm.
Place in Copenhagen, that newly designed: Tasinge Square, SKT. Annae place, Enahue park (the park becomes a reservoir, then a park again in 24 hours) and The soul of Norrebro.
Financial and economic issues, political backup, different wishes to urban life, clash of professions: different experts need to compromise and have a working solution that is good for the city.
Things I learned about New York:
Hot days and wet days are increasing. According to NYC Department of Environmental Protection, rain is going to increase 4-11% by 2050 and 5-13% in 2080.
Green space in NYC is limited. There is NYC program called Blue belt, which restores wetlands. It is a natural solution for stormwater management.
Green infrastructure: Retrofitting NYC streets, creating rain gardens. (PS261, BK)
During extreme events, there are technical restraints, they will partner on cloudburst management. There are 6 restraints: Community, flooding canal, green space, cost benefit, and co-benefits
NYC has started to look into a natural flow of water. Asking questions, such as; Where does water go? Where do you want it to go?
The city is also looking into making bike paths waterways during a storm. It is called ‘Green corridors for water.’
South Jamaica houses have an active gardening community, so in that scenario water will retain for plants and excess water will be taken out.