Though my family lives in Sacramento, I spent this past Christmas at the beach in Ventura. While there, the parking lot of the hotel we were staying at flooded. While the rain that night was heavy, it was surping just how much the parking lot flooded. Spending time at the Pacific Ocean, I was reminded of sea level rise. After some reading, I now understand that with the oceans on the rise, even a little rain (or no rain) can cause a great deal of flooding on the coast.
When the sea level is above the outfall pipes, flooding can happen even on sunny days.
Source: https://sealevelrise.org/states/california/
Back home in Chicago, there’s a large body on the rise as well. Fall of 2019 there were a number of articles about the issues Lake Michigan’s rising levels are causing all along the “coast” of Chicago. From up north in Rogers Park to down south in Hyde Park, the Army Corps of Engineers, Park District, and other city agencies are scrambling to mitigate some of the damage.
So it would appear that bodies of water on the earth’s surface are rising and it got me to wondering why and what’s being done in response.
California
Sea level rise has four main causes. The cause I am most familiar with – and as you may have already suspected – is a warming planet causing ice melt that increases the volume of water in our oceans. Another is that warmer temperatures cause the waters to expand, taking up more space and encroaching on coastal areas. These two are the most relevant to California. Two causes that are more dependent on local conditions include sinking land (!) and the Gulf Stream slow down.
While my first instinct was to bemoan the fact that in California we built right up to the edge of the ocean, it turns out California was building during a time of “sea level rise suppression” that went unnoticed by scientists. “A rare confluence of favorable winds and cooler water” kept California oblivious to the coming destruction of sea level rise. This was an ah-ha moment for me as I realized I mostly associated sea level rise with the east coast, which has been dealing with this for much longer and on a much more intense scale.
But the period of calm is over, now what?
Seawalls have been keeping back the ocean, yet they eliminate beaches when the seawalls prevent the natural replenishment of sand that comes from the cliffs. As the ocean rises, what remains of the beach vanishes beneath. Because of this, states like Oregon and Maine have banned seawalls. In California, the Coastal Commission urges cities to use seawalls as a last resort.
Another option is “managed retreat,” when a community moves back or relocates. In other words, when a community accepts that it can’t keep nature at bay with a wall.
In Ventura County, where I spent Christmas, a plan was approved to move a parking lot, pedestrian path, and bike path away from the tideline. Brought up in the mid 1980s, phase one was only completed in 2011. The alternative was building a seawall that would have destroyed a famous surf beach at Surfer’s Point. While this effort was eventually successful, it’s important to note that no homes were removed or moved – the greatest cause for controversy in managed retreat.
California has 1,200 miles of shoreline. It’s going to take a lot of collaboration and work to address this issue.
Chicago
Lake levels naturally rise and fall due to weather and other natural causes and, according to the research, there isn’t necessarily a pattern that lake levels follow. Chicago, it turns out, is sinking. One cause is densely built areas that put greater weight on the earth’s surface and another is isotatic rebound: Chicago’s landmass is actually lowering in relation to the landmasses in the northern Great Lakes Basin, which are rising.
While climate change is causing drought in some parts of the country, in Chicago it is causing greater frequency and duration of storms: “near-record precipitation fell over the basin in 2018 and 2019, tipping the lake’s balance between water inputs and evaporation.”
The city’s response has been to place concrete Jersey barriers along the bike path between the lake and Lake Shore Drive. From up north in Rogers Park to down south in Hyde Park, the Army Corps of Engineers, Park District, and Chicago’s Department of Transportation have been trying to address the damage already caused by and protect areas from the Lake’s lashing waves. Elected officials in the Hyde Park and Kenwood neighborhoods have partnered to create a lakefront erosion task force to brainstorm solutions.
Riding the bus home from work each evening and looking out the window, it’s painful to see large sections of the bike path chewed up from freezing and refreezing of large lake waves. The only thing getting me through the cold winter months is thinking of the runs and bike rides I’ll take along this path in the spring and summer.
In California, the City of Chicago, and elsewhere these bodies of water are on the rise and addressing the damage caused is no small feat.
Additional resources:
http://elpc.org/wp-content/uploads/2019/03/Great-Lakes-Climate-Change-Report.pdf
https://www.latimes.com/projects/la-me-sea-level-rise-california-coast/
Chelsey in Chicago 