When it comes to the flood of 2010 in Cranston and Warwick, we can’t blame Mother Nature. According to Brown students, man-made changes to the land in the Pawtuxet River Valley are accountable for increased susceptibility to floods.

Their studies of hydrology and precipitation over the last century have led them to the conclusion that the increased amount of impervious surfaces has led directly to an increase in flooding. Impervious surfaces include paved roads, sidewalks and heavily compacted soils due to urban development.

Six research groups of students shared their findings in a series of presentations held at Brown’s Urban Development Laboratory last Thursday. Students spent the last two months conducting interviews, poring over data and examining maps of Warwick and Cranston to answer the question, “What have we learned from the March 2010 floods?”

Melissa Palmisciano, a Warwick native, said she was intrigued to be working on a project that hit so close to home.

“It was really, really cool to apply the stuff I’m doing in school to Rhode Island,” she said.

The project was for Analysis and Resolution of Environmental Problems and Case Studies, a class at the Center for Environmental Studies. The students were under the leadership of Department Director and Professor Timmons Robert, with the assistance of Lauren Watka, a graduate student in the program.

“The students interviewed a diverse range of distinguished community leaders and experts who all contributed unique insights into the flood’s causes, impacts and long-term implications,” said Watka.

Their presentations were followed by a panel discussion that included experts from the university, Save the Bay and West Bay Community Action.

“The report was spot on,” said Paul Salera of Westbay Community Action.

In addition to identifying the issue of impervious surfaces, students also found that flood insurance rate maps are outdated, and zoning and building code regulations are not strict enough.

Their studies examined low-income households built in areas more prone to flooding and the lack of adequate insurance available to renters. Because people often don’t understand their flood insurance and how Federal Emergency Management Agency (FEMA) assistance works, many people were left afraid and confused during the floods. Brown students recommend improved access to resources and a better means of communicating information to citizens.

“We had over 190 families in hotels,” said Paul Salera, Director of Family Services and Housing at West Bay Community Action, “Because there were so many people from FEMA and the SPA that bought up hotel rooms, we had to send our citizens to other places, some as far as Massachusetts, which made it difficult for families who still had children in local school systems.”

However, not everyone was negatively impacted, and students named hotels and hardware stores as those businesses that benefited from the floods. Kening Tan, a student who worked on the study entitled “Who were the winners?” presented data that showed unemployment rates temporarily dropped in the period after the floods.

“The labor market showed gains during the flood recovery period,” said Tan.

Mayors Allan Fung and Scott Avedisian benefited from the floods, too, said Tan’s group. Their media attention on the national level increased their popularity.

Overall, students found that three key things have to happen during floods like the one of 2010: prepare, take action and communicate.

Caroline Karp, a Brown University senior lecturer and member of the discussion panel at Thursday’s event, said that we could have seen the flood coming.

“A lot of this would have been predictable given what we know about the hydrology of [The Pawtuxet River] basin,” she said.

Though Karp said she was impressed with the response to the crisis, she noted that the RI Green Building Council offered their emergency response services and were declined.

She also touched on the amount of impervious surfaces surrounding the Pawtuxet and said that underneath those surfaces the ground is quite permeable. She used Warwick Mall as an example and explained that its proximity to the river was questioned by Save The Bay at the time of its development. She asked the students how flooding could be solved in this location.

Bridgette Black, a student involved in the studies, suggested Warwick Mall be retrofitted for improved flood patterns.

“They’re going to repave the parking lot every few years anyway, why not use a pervious surface to do so?”

Some students may follow up on the cost analysis of such an idea.

Karp posed another question: What happens to industrial developments towards the mouth of the river.

“What if they have onsite toxics? Say a property is maintaining hazardous waste and it gets flooded. This a serious, unmentioned risk,” she said.

Student Cathy Chan referenced some of her findings to address this issue.

“Things could have gone really badly in Cranston,” she said. “There was a plant with 200 barrels of hazardous waste at the time of the floods.”

But, she said, they were able to respond quickly and avoid spillage during the flood.

Another panel member, Rachel Calabro, community organizer and advocate from the Save the Bay, brought up the issue of poorly maintained dams.

“Three to four dams failed during the 2010 floods,” she said, “This caused about $1.4 million in damages to roadways. The state owns less than 10 percent of the dams. We need to ensure private dam owners inspect and maintain their own dams.”

Calabro said that many privately owned dams are no longer active, though some are still used by mills for fire suppression.

“The recommendation we would like to make is that unwanted and unused dams be abolished. Private owners need to understand that dams are a liability. They need to incur the costs of maintenance or else aid in removal,” she said.

She also addressed the suggestion of dredging.

“Rivers move a lot of sediment on their own,” said Calabro. “Dredging a river doesn’t bring you any more flood storage.”

Professor Timmons Roberts said he was impressed with the students’ work and their findings.

“The floods revealed many ways we’re vulnerable to weather-related disasters and opportunities to address some complex problems like…zoning in floodplains…insurance and disaster relief and our emergency preparedness,” Roberts said.

The students’ reports are now available for perusal on the Center for Environmental Studies website.