The National Weather Service Forecast Office says the North American Monsoon System affects New Mexico and other areas across the Southwest every summer between June 15 and Sept. 30. During that time, large amounts of rain can fall astonishingly quickly, but where does it all go? How is it managed?
Jack Kirby, assistant director of New Mexico State University’s Environmental Health and Safety office, runs New Mexico State University’s Storm Water Management Program, which is mandated by law and monitored by the Environmental Protection Agency.
“Public entities above a certain population are required to have a water management program. The city has a storm water management program, NMSU has a program, Dona Ana County has a program,” Kirby said. “It’s EPA’s approach to containing nonpoint source pollution.”
Nonpoint source pollution comes from a large area, like a parking lot. There is not a single source of the pollution – it’s an aggregate of many small forms of pollution, such as chemicals or debris, found in the lot. When it rains, storm water acts as a universal sweeping mechanism across the drainage area, bringing with it the contaminants that may be in the lot.
NMSU’s initial SWMP report to the EPA in 2009 contained 36 “best management practices,” which are areas the university improves upon each year. There are six components to the program: public outreach and education, public involvement and participation, illicit discharge detection and elimination, construction site storm water runoff control, post-construction storm water management, and pollution prevention.
Much of the landscape design on campus was created to manage storm runoff. From swales to cuts in curbs, it all serves a purpose.
“Mostly what you see – some are subtle, and some aren’t – are sloped swales. They route the storm water runoff, maybe around the building into another area to run it down the hill. These swales are there to slow that velocity to help the water sink into the ground,” Kirby said. “Or, it could be a desert landscaping area that has a small curb cut that allows water to soak into a desert feature and temporarily pond, then soak into the ground.”
An effective storm water management program strives to mimic pre-development conditions of the developed area. For instance, if the NMSU campus did not exist, the land it sits on is a sloping desert area, and while there would be runoff, there would also be a lot of infiltration. Buildings, roads, sidewalks, parking lots and construction sites all interrupt natural runoff and infiltration, but proper management can mimic the natural process.
“We’re trying to maintain that infiltration and at least not make the situation worse as far as infiltration and runoff,” Kirby said.
Many structures on campus use gutters and pipes to direct runoff into landscape features for infiltration, while some divert water to gullies and ponding areas, where it will eventually be absorbed, or managed via the storm sewer system.
The primary contributor to storm water runoff from a volume standpoint around a building is a roof.
“Managing that is where smart design comes in,” Kirby said.” If a building has eight or 10 downspouts, they can flow a large volume of water. You can shoot it out into the street, and now you have a river running down the street, or you can design your landscaping to contain it.”
NMSU’s newest building, the Center for the Arts, was designed to contain a 100-year, 24-hour storm event, which is a significant amount of rainfall, in its footprint.
“The way the Center for the Arts contains a storm of that size is the roof drains are routed to an underground cistern system, which I believe is about a 50,000-gallon volume,” Kirby said. “There is porous pavement in one portion of the building site, and there is a small detention pond area. All of these features control that water, allow it to slowly infiltrate back into the ground and become groundwater, without creating runoff.”
Kirby acknowledges that there could be a larger storm, which would result in runoff, but design must strike a balance between the desert climate and what is a reasonable amount of water to contain.
The Sam Steel Regional Pond, on the corner of Sam Steel Way and Union Avenue, is at a topographical low point on campus. Most of the water that runs off the main part of the campus works it way to that pond, while there are other places where water can work its way into the City of Las Cruces storm sewer system.
“A portion of our water goes to the city system, but probably about 70 percent goes to that pond,” Kirby said. “From Sam Steel Pond, there’s an outlet that takes that water to a drain, which ultimately goes to the Rio Grande. The onus is on NMSU to deliver high-quality water. Water that flows onto our campus, we’ll check that, too, to make sure there’s no contamination, taking occasional samples in times of runoff. And, I would hope and I do know that folks down the stream from us do the same. That’s how permit holders ensure that they’re not making the situation worse, nor are they receiving contamination from their upstream neighbors.”
See something, say something
“When I talk to groups on campus, I ask them to be our eyes and ears,” Kirby said. “If something doesn’t look right, whether it’s the quality of the storm water, some contamination question you may have, or a volume concern you may have. Call us, and then we can address the issue.”
Individual habits of those residing, studying and working on campus are important, too.
“If you throw a Styrofoam cup on the ground, it’s either going to blow away, or drift down into our storm water system. It could clog an inlet to a storm drain, which could then contribute to flooding a building,” Kirby said. “Your personal habits – we have residences on this campus. Changing their oil, pet waste, fertilizing your lawn – all of these can contribute to run off. Good housekeeping practices can help. The easiest and most important is to contact Facilities and Services to report it. Common sense goes a long way.”
To learn more about NMSU’s Storm Water Management Program, or to report a storm water-related concern, visit http://safety.nmsu.edu/programs/environmental/SWMP.htm. To report a violation or concern by phone, call 575-646-3327.
Information from NMSU