Where the Rain Goes

July 20, 2011

RICHMOND, Va.- Over the past year, 245.36 inches of rain and other moisture fell on Richmond city. That output is from 483 different storms, some of it consisting of 30 snow storms, 38 thunderstorms, and 192 rainstorms, according to the National Oceanic Atmospheric Association.

All of this moisture and water, however, all went through the same place: the storm water runoff system underneath the city.

The amount of pipes running underneath the city spans 64,000 acres, according to Robert Steidel, director of the Department of Public Utilities in Richmond.

Two-thirds of the city has their storm water runoff go straight into the James, while the other third has to go through the wastewater treatment plants due to how old the infrastructure is in that part of Richmond.

“The first two-tenths of an inch every hour gets fully treated,” said Steidel.

“However, if there is more rain coming down that, it gets partially treated before its dumped so the system doesn’t back up,” said Steidel.

A table showing total rainfall over the past year, with other graphs about how much it deviates from the norm as well as how it compares to rainfall a year previously. Source: National Weather Service

Dr. Todd Lookingbill, an assistant professor of Biology at University of Richmond, notes that due to this partially treated nature, safety in the James is a concern.

There are around 30 places around the James where the partially treated water enters the James, called combined sewer overflows. Due to these overflows, some e. coli enters the river.

“It is not a good idea to go swimming the James immediately after the rain,” said Lookingbill.

As part of its budget, the Department of Public Utilities maintains the storm water system throughout the city, with unpredictable consequences.

“After a major storm, you’ll see sinkholes or ruptured pipes, which is part of the $7.4 million spent to operate the department,” Steidel said.

Part of the maintenance for the system is to replace old pipes. Pipes can be in the sewer system for up to 60 years, and replacing the old pipes is another cost.

Dr. Mohamed Gad-el-Hak, a professor at Virginia Commonwealth University who teaches mechanical and nuclear engineering, explains what type of pipe is used for storm water runoff.

“The pipe is usually 2 to 3 feet in diameter, and it is designed to run with low pressure,” said Gad-el-Hak.

“Since the rain is occurring over the huge surface that is the city, the pipes need to be able to move a lot of water fairly quickly,” said Gad-el-Hak.

The biggest concern for storm water runoff, however, is clean drains.

“When you see water backed up at street corners during a rainstorm, it’s due to people throwing cans, cigarette butts and bottles into the drains,” said Steidel.

While it doesn’t cause damage, clogged drains lead to lanes of traffic becoming blocked as well as roads sometimes closing.

“The pipes that you install have to be clean and have a capacity, otherwise whenever it rains it can close traffic until the water is drained,” said Gad-el-Hak.

The Department of Public Utilities cleans nuisance areas immediately when there are issues, but only thoroughly cleans each street every three years according to Steidel.

The number of each type of storm that occurred in Richmond from July 2010 to June 2011. Source: National Weather Service

There are a few strategies to dealing with storm water runoff in Richmond. One way is to install a rain barrel where your water spout empties.

Rain barrels vary on size, but they are designed to capture water during a rain storm so that it can be used later when it isn’t raining to water gardens and lawns, or possibly wash a car.

Green Unity, a student environmental group at Virginia Commonwealth University, sells the rain barrels as part of fundraising for its organization.

“We’ve sold ten so far,” said Rachel Elves, a member of the leadership team for Green Unity and a graduate student at Virginia Commonwealth University in Human Genetics.

“They’re great devices,” Elves said. “I have three daisy-chained together on each of my two water spouts at my home.”

The city of Richmond also gives tax credits to homes that install rain barrels and other storm water runoff reducers.

Rain barrels, by managing storm water runoff, help prevent soil erosion as well.

“The bare earth flushes away the top layer of soil, which has all the nutrients plant need to grow,” Elves said.

Erosion also occurs close to the banks of the James, where developments are built.

“The area of land near the river act as sponges, slowing the flow of the water and scrubbing the water of nutrients and other contaminants we’d like not to see in our water,” said Lookingbill.

The state of storm water runoff, however, is much better than it was a hundred years ago.

“What we do is a public health service,” said Steidel.

“Because of us, there isn’t typhoid or tetanus, which were both prevalent before modern sanitation.

“When people get up in the morning, they don’t have to worry about anything to do with sanitation because we make sure it is as clean as it will be,” said Steidel.