Tracking Sand: Scientist researches sea level rise, erosion in RI

As global climate change increasingly becomes an issue of international political concern, a URI scientist is conducting research to better understand the effects of climate change and sea level rise here in Rhode Island.

Part of the work of John King, professor of oceanography at the University of Rhode Island Graduate School of Oceanography (GSO), focuses on coastal erosion and sea level rise in Rhode Island.

One of King’s projects is a monitoring program for coastal erosion funded by the National Fish and Wildlife Foundation. “Since the early 1960s … GSO has been monitoring volumes of beach sand on the south shore of Rhode Island using kind of traditional surveying methods,” King explains. “But the problem with that approach is that it’s kind of limited.”

These traditional methods involve observing eight narrow strips of land in different places in southern Rhode Island and using the profile, or sample strip of land, to calculate out how much sand is on that beach. “We know a lot about eight places about this wide,” he jokes, indicating a short distance with his hands.

The new monitoring system uses LiDAR, short for Light Detection and Ranging. It works by shooting a laser at the shore, which bounces back to a detection sensor. Hard or reflective surfaces return more light back to the sensor than soft, absorbent ones. The result is a dense group of points, each with a latitude, a longitude, and an elevation. With this data, scientists can see exactly what a beach looked like at the time of the survey, and can figure out how much sand there was and where. “You can mount this device on a boat and just cruise along the coast. And that way you get continuous coverage … We can cruise the whole south of Rhode Island in a day with this system.”

The increased speed of LiDAR also allows more flexibility in when data collection can be done. King explains that ideally these measurements would be able to be done immediately after a big storm. Often, post-storm measurements aren’t done until quite some time after the actual event – often a matter of months.

“They’re quantifying the damages after a certain amount of repair has occurred, and that’s not as good as trying to do it right away.” King wants to figure out what kind of damage results from which conditions. Ultimately, this kind of data will help to predict what kind of damage can be expected from storms of different given magnitudes.

East Matunuck Beach | Photo Meredith Haas

East Matunuck Beach| Photo Meredith Haas

These predictions are important, because storm damage is set to be an increasingly problematic issue as sea level continues to rise. “Sea level is rising pretty rapidly,” King explains. “It’s the combination of the sea level rise plus the temporary sea level rise caused by a storm that damages the coast.” The damage is further exacerbated by the big waves that occur during a storm. And, King emphasizes, this damage isn’t going away. “When you raise sea level permanently, which is what’s happening with the melting of the ice sheets, your baseline is higher. So things just get progressively damaged over time.”

In Rhode Island, rising sea level has the potential to cause a lot of damage. The topography of much of the state is relatively flat, so sea level rise would cover a lot of ground. King notes that recent estimations predict as much as 8 feet of sea level rise by 2100, which could put most of towns like Barrington and Warren under water. And coastal erosion worsens the process, stripping the coast of beaches that would otherwise act as protection for the land behind them. This is why King is involved in another project that looks at ways to replace the sand lost to erosion. Upland sand resources are becoming depleted, he says, and thus sand is becoming more expensive. A grant from the Bureau of Ocean Energy Management has provided funding to look for offshore sand and gravel resources to replace those lost from the beaches.

Unfortunately, the use of offshore sand resources comes with another price: destruction of underwater habitats. Because of this, King says that this option must be considered carefully. And even if these resources were to be utilized, it would only be a temporary measure. King explains that replacing eroded sand would really only buy time to plan more permanent measures: “Most people think that given the combination of increased storminess and high rates of sea level rise that the only option we have is to retreat.”

Engineering solutions might be possible to protect what can’t be moved, but these would be very expensive and not immune to failure. “All you have to do is look at what happened with the levees in New Orleans to know that there are some pretty significant limits to what you can achieve with an engineering solution. We’ve already got a hurricane barrier to downtown Providence, but that was designed for present sea level.”

He does worry that the issue isn’t seen as pressing enough – that it only makes headlines when a dramatic storm like Superstorm Sandy strikes, but is often soon eclipsed by other matters. “Public attention is fleeting. In the 24-hour news cycle, things fall off the radar pretty fast. If right now you were to ask people what the number one problem is from a human health perspective, science would objectively say climate change. I think the general public would say ISIS and international terrorism.” Recently, he says that he’s been encouraged by the Environmental Protection Agency’s recent regulations of CO2 emissions by power plants. King says that there have been some good signs in Rhode Island as well.

“We’re lucky we have a relatively simple management structure in Rhode Island and people that know about the science are going full bore trying to convince policy makers that this is a crisis and we need resources to address it.”

By Keegan Glennon | Rhode Island Sea Grant Communications Intern