City College of New York, School of Architecture
Catherine is in her 2nd year in the Landscape Architecture section of the School of Architecture, studying climate change and adaptation, and how designed adaptation can make places better to live.
In NYC, we can look at estuaries and how to mitigate the risk of storm surge. Storm surge barriers and hard infrastructure often winds up being under-designed, especially with climate change and rising storms and sea level.
Catherine’s solution is soft infrastructure, features that are more like nature, can be built iteratively, and allow some flooding but lessen the destructive effects.
In conjunction with her husband, a structural/civil engineer, she works on Big Ideas (large scale projects) that can be used by entities like the City of NY consult for waterfront planning. Coming from the outside, they can present ideas that the city cannot commission (political or economic concerns).
(Tri – So you build things without asking?)
Catherine: No, it’s just proposals, ideas, and research. Much of it is based on the Rising Currents project (book passed around).
The idea of using sediment is to use what’s on hand.
Problem: The Tiber river flooding.
Tiber drains much of Italy, with many major floods in Rome (major floods in 1594, second in 1870, year of Unification – that’s for Marco).
Anecdotally, flooding in 1870 was so extreme that the new premier of Italy got his feet wet at the theater. Plaques on walls (Idrometro) in Rome show flooding at 2-5m, with the dates of the floods, so we have good records.
After the 1870 flood, flood walls were installed along the Tiber, re-orienting the relationship of the city to river. Where previously it had sloped naturally to the river, now there were artificial walls and a separation. This (in effect) raised the elevation of the city, lowered the waterfront, allowing controlling of the floods, but losing the river. This changed the relationship between the locals (who put their valuables up high) and the river.
Her (and her compatriots) wanted to create a model of the Upper Bay of NYC. Their insight is that the land is a continuous surface. It doesn’t magically end at the water’s edge, it goes underneath. The land is a static vessel, while the water is a dynamic. To model this, you need to merge bathymetry and topography (NOAA and USGS).
From their model, you can see the underwater topography. The Verrazano Narrows is the deepest part, which is good for shipping, but much of the shipping comes through the Kill van Kull. The Army Corps of Engineers is dredging the harbor for bigger ships, but sediment keeps coming in. ut sediment keeps coming in. They are using the sediment to cap a contaminated site just outside the lower bay (HARS) or are using it to reinforce Jamaica Bay.
Their latest proposal is for a new Upper Bay, an infrastructure project to mitigate the effects of sea level rise, wave energy and to create a place for people using a combination of hard and soft infrastructure. Using their models, they used 100 and 500yr flood maps from FEMA and a SLOSH map to show the flooding from various hurricanes (even cat 1 shows extensive flooding). This is to mitigate storm surge from these large storms.
Examples - Subway cars, wind power + oyster beds, slips coming in to lower Manhattan
Maps show where the various oyster flats used to be – these became anchorages (safe place to keep a ship), initial conflict of mussels v shipping.
Introduces the book On the Water: Palisade Bay (2010) (Lines on the cover are hurricane tracks.)
For sea level rise, Rapid ice melt scenarios drastically change the shape of the NYC coastline. Jamaca bay, lower Manhattan, the Rockaways, Long Island Sound, even Florida. Lose much of the lower elevation land, in some places it is extensive. The new ‘space’ is called Palisade Bay (a play on palisade cells in a leaf, keep the water in , photosynthesis – the idea that it is a barrier, but a porous one).
This is looking specifically at the Upper Bay – Northern extent of the Holland tunnel, Brooklyn bridge, down to the Kill van Kull and the Verrazano Narrows.
(Tri – Shipping lanes?)
Most shipping still comes through the Arthur Kill/Kill van Kull up to the port of Elizabeth, and the shipping channels aren’t being changed (also, shipping is relatively green!).
Some sections of the bay are very shallow. With slip and pier topography + bioswales it would be relatively simple to put things back to a natural water-land interface.
Using their model, they can see how much is innundated with SL rise and storms. The numbers (for storms) change as SL rises (1.2 in/decade at the Battery). The baseline is changing, and will be much much higher in 2080 according to predictions (additional 12-23 inches by 2080). In a rapid ice melt scenario, this is 44-55 inches (higher than the storm surge from the Long Island Express, the big storm in ’38).
Hard infrastructure ideas are things like storm surge barriers. Possible in LI sound, the Verrazano Narrows, and mouth of the Kill van Kull (protecting Manhattan and the Upper Bay, but leaves Jamaica Bay). Examples of these in Rotterdam and London, but these may already be under-engineered. These are incredibly large, Hoover Dam-level projects.
The idea of ‘Place’: the 19th century idea of making place as seen in Central Park as a void where you can go. Can we make the Bay a place where one can go?
Central Park is not natural - sightlines are controlled, waterways controlled, drained with pipes, waterfalls with on/off valves. And the infrastucture leaks, and may not be completely working.
(Sam – the Central Park Conservency got a $100M grant to fix this)
Prospect park absorbs their water, but Central Park actually drains it. (Man vs. Nature).
Can we make this more like the Grand Canal and Piazzo San Marco (?) in Venice. The water is where people are, rather than as a void.
The Deely water map (and Museum of the City of New York) show a map of NYC, post grid (the grid from 1811) showing how the various waterways in NYC have nothing to do with the grid. This can cause problems – highlands, lowlands, made land vs. interaction with natural water courses (engineering vs. nature).
Pier line + the bulkhead line – like “cilia”, show where the shipping was. The edge of the city is fully built out, with a bulkhead line along much of Manhattan, along Brooklyn, etc. It is no longer a natural interface, completely built up. So what can we do to make a more natural edge?
It’s possible to extend out, use breakwaters, use still water/retention ponds, etc.
These are ways to dampen wave energy. Basins and slips will pull water inward.
This can be done using detrius – Shooter’s Island, an artificial boat yard island, is now a bird sanctuary, and can change the way sediments and currents move.
In order to see how to mitigate wave energy, they used water tables to see what happens when adding islands and using different shaped piers.
Doing this on computers is difficult. To model some offshore piers near Bayonne, it’s very computationally heavy, hard to run. You must ‘wet’ the model, and then the model just runs up TO the land, on ON to it. A smooth water/land interface isn’t well modeled.
The idea is to create things to change the wave dynamics. For example, oyster beds mitigate wave energy, and oysters to do some of the pollution cleaning. Slips in sunset park, or archipelagoes of islands to break up wave energy. If you combine all of these in the Upper Bay with slips, detachable piers, subway reefs, wind farms and oyster beds, you can mitigate the wave energy and create a place to go.
(Tri- If you create places that you want to visit , need to be able to get there without a car – what about the size of cargo ships, water taxis)
The next slide was some ideas for water taxis (nice). It may be possible to make connections between Brooklyn, SI, NJ – but direct connections. They floated (pun intended) the possibility to add some kind of linear or floating developable land structure, and using water taxis as extension of current subways
(Tri – So you can go to the edge of the water, and then get here with a water taxi)
Right. Now, you often have to go deeper in to get the subway, then go back to the other side
(Sam - Question on CSO/runoff)
There is a big problems with CSO’s. How do we prevent some of the outfalls and overflow? Well, if you can absorb the water, and not put it into the sewer pipes.
(Sam – What parts of this plan does the city like the most)
Some of this is in the Waterfront Plan 2020 + the latest update to PlaNYC. Now climate change is included, and the map of the Bay now includes NJ (better for a more holistic view).
They advocate absorbtion, green roofs, etc, to mitigate flooding, CSO’s, to let it percolate slowly instead of going directly into the sewers.
This is a book, but also a workshop/exhibition at PS1 / Moma. This was a ‘competition’ with 5 groups/teams who each had a section of the Upper Bay.
Liberty State Park. This is very low (+1 foot above SL). The idea is to crenellate the edge, adding slips, making this much more adaptable to flooding. In Kill van Kull, the old oil tanks can be reused as biofuel production. Recycled glass is used as an underwater habitat and for wave mitigation. This allows the use of lots of recycled material.
In Sunset Park, the idea is to let the water in by creating retention basins in underutilized lots. In times of heavy rain, these can retain water. Housing can be developed right at the edge of the water, and it’s possible to create and outer band of artificial islands. These might have inflatable dams to protect from large floods.
The low area by Red Hook can house new oyster reefs, using the Gowanus Canal as an oyster nursery (problem: you can’t eat those oysters, but people might try to harvest them anyway).
(Tri- So what about pilot projects?)
They are doing some small scale pilot projects, like creating offshore reefs. These are things that are easily transportable to other places. Some of the other ideas (piers) are dependent on location and scale.
Now talking about a larger scale, sediment driven location, the Mississippi Delta. Here, silt is the driver. How can we harness that huge amount of sediment? There’s a problem with the bowl in NOLA, and with the engineering of the river. Because of the creation of the levees along the river (out of reeds – James Eaves) and making the channels narrower, they became deeper, faster, and move more sediment – right off the edge of the continental shelf. This is a problem because the silt/sediment nourishes the wetlands, so the wetlands get worn down/sink/get washed away, and so you’re both losing land and protection for the places more inland. The other problem is the river wants to move (jump the channel, as it has in the past, as seen in maps showing the meanders and oxbows).
In the bayou, people live with the wet and dry (Beasts of the Southern Wild) as an adaptation strategy.
If the sediment supply can increase, you can build up land and SL rise gets arrested (or at least doesn’t rise so fast), which provides protection and can create new land. However, it’s likely a losing battle (deposition vs SL rise).
There are proposals to use the Atchafalaya to increase sediment supply to the Gulf. The Army Corps is struggling against that – they look at this more like plumbing than natural processes. The edges are hardened, reinforced, and the idea is to protect the Port of New Orleans.
There are places where you can open up the flow and grow land (Wax Lake outflow is showing this!), but the amount of flow is actually Federally mandated!
The model created for this was done in the same way as the Upper Bay model (continuous land, with water on top) and exhibited in Venice.
Project #3 - Yangtze Delta Ridge
This project is about bringing in an exhibition of research work from a city on the Yangtze River, where cyclones are a problem. There is a sedimentary plane where deposition is happening. They are creating catch-basins and harder infrastructure using sediments based on the idea of Chenier ridges (made of shells) that grow up as a region is growing out. Using these, and the ideas from soft infrastructure like the walls of rice paddies you can make large-scale water retention basins and flood control structures that can mitigate (not prevent) the effects of cyclones.
This is similar to (but different than) the cut and fill process for making dikes in places like Holland. However, in Holland they have a lot of hard of infrastructure and lots of pumps.
Questions and Discussion
(Kamila – Have you done a financial cost assessment?)
No numbers, yet. In China, it’s easy to do large scale earth moving projects, and to do it quickly. The Army Corps also loves moving sediment around. We also like to talk about the reuse of construction rubble and other things.
(Gerry – How do you sell this as protecting things when, historically, we don’t work with the weather we fight it)
Yes, this is a problem! There’s this ‘War on Nature’, where it’s the enemy. We talk about lines of retreat, very militaristically when we’re looking at this. We want to rethink the relationship here.
(Tri – From the book I’m reading (for report), and talking about the way that infrastructure is built – meteorological data is often used because we want to CONTROL the weather)
Yes, this is not a good way to look at this. It’s in the interest of us to work with this, but much of the interest in this is from the military.
(Gerry - Again, on the same point – We are used to looking at weather as a PROBLEM)
True. City is looking at freeboarding – putting the infrastructure up higher. We’re trying to gain acceptance of the ideas of Wet and Dry flooding. In ‘Wet’ flooding, you don’t care if it floods – the stuff you need is upstairs. Things that you can deal with flooding are down, things you can’t are up (12 ft about sea level). Dry flooding – waterproofing, all the infrastructure is in waterproof boxes. This is dependent on how good your building is, how much you maintain it.
The Army Corps is very active. While we could use passive solutions, the infrastructure is so built up that there is a desire to protect it.