3 problems that water abundance brings to coastal communities

Water is necessary for life, and billions of people around the world still lack access to a healthy supply, while more live in water-stressed areas. Yet with increasing impacts from climate change, coastal communities face the opposite problem: far too much water.

With 30 percent of the world living near coasts, here are three major problems, and some progress on finding solutions for the coming decades.

1. When it rains, it pours: stormwater

Warmer oceans lead to more water in the atmosphere, and more precipitation. Often, however, that rain or snow comes en masse, as with Hurricane Harvey, the 2017 monsoons in Bangladesh or the four nor’easters that the Northeast Corridor has seen in the past three weeks. Add in stronger winds pushing more of the ocean onshore, and you have storm surges that flood whole towns or districts — or Lower Manhattan.

2. High tide at high noon: tidewater

Many low-lying coastal areas do not need a storm to flood — higher tides lead to residential streets flooding under a blue sky. Whether in river deltas, or throughout the southern half of the U.S. eastern seaboard, what is called "nuisance flooding" is becoming more of a regular part of life.

Further, the communities affected are often lower-income or marginalized, making them less likely to see broader engagement or support for finding ways to manage or live with the water. One option: making events out of the worst events as a way to test models for future planning.

3. Nowhere to go: groundwater

More precipitation, all at once, also leads to another problem: filling up the ground with water, leaving nowhere for the next storm to soak in. For some communities, this leads to additional flooding with successive storms, and in others, hillsides become waterlogged and slide off, as experienced by both rich California towns such as Montecito and poor communities around Freetown, Sierra Leone, which lost more than 1,000 people in one event last summer.

Water, water, everywhere: responses

Most of these problems are not new; there have always been monster storms or drenching rainfall. As a result, we have a range of basic responses: physical barriers as in London, better foundations for hillside construction, avoiding building in flood zones or building raised houses.

Climate change makes the rare events more likely, with more continuous damage and an increasing set of communities affected. Standard responses often focus on resistance — protecting against another foot or three of water for this neighborhood — often missing those without a strong voice. What’s missing from our arsenal are two aspects.

First, explicitly designing communities to enable rapid mitigation of climate change, through energy, transportation and sustainable food systems. Everyone — rich or poor, Miami or Dhaka — benefits if strong storms stop getting more frequent or tides stop rising. Second, for the impacts that are already here or coming, low-cost adaptation measures that can help as many communities as possible, either for short-term reprieve while planning approaches change or a long-term stabilization without huge maintenance costs.

If you have a solution for one of these aspects, or want to work with those that do, MIT Solve would like to hear about it and help the best ideas get implemented around the world. Let’s find ways to manage the excess water climate change is bringing, even as we find ways to bring clean water to everyone in the world (and we have some solutions for that, too).