Building bridges

It does not take a hurricane to put some rural roads in Missouri’s Webster County under water. Rain storms can inundate road crossings where simple concrete slabs span creeks and small rivers. In just the past few years, however, the county has used geotagged photos to receive more than $1 million in FEMA grants to replace four often-flooded crossings with new bridges. “Low-water crossings have no address, so we document their locations with geotagged photos and plug them into a map to show where they are,” says Linda Watts, Webster County assistant emergency management director.

Flooded crossings cause greater problems for the county than simply tying up traffic when the stream swells in a rainstorm, Watts says. Flood waters usually carry debris, and the floating logs and branches inflict repeated damage to the crossing and the road surface. Keeping them repaired can be a constant battle and revenue drain.

In 2008, the county purchased the same photo-mapping software and digital cameras used by Accomack County. Every time a crossing floods, someone from Watts’ office is on the scene photographing the high water and related damage. With 100 low-water crossings in the county, the location- and time-stamped photos show a pattern of repeated floods and destruction at specific places, which builds the case for bridge construction. “We can document with the GPS camera that it’s the same location [that’s flooding] over and over again,” Watts says.

Plans are under way to load the photos into the county GIS, but for now, the agency prints the geotagged photos along with a location map and sends them to the state, which must submit the grant request. To date, Missouri has successfully requested bridge-building funding for Webster County from two disaster mitigation grant programs managed by FEMA.

Preventing flood fraud

Since 2009, Fargo, N.D., has experienced unprecedented flooding from the Red River, which runs through the center of town. Over the past three years, the Fargo Engineering Department has become especially skilled at quickly building levees and sandbag embankments to protect property in and around the city.

Fargo’s policy is to pay private property owners to repair any damage inflicted by municipal vehicles when sandbags and other levee-building materials were used during a flood. “We use heavy equipment to put clay and sandbags in place, and we go into people’s yards,” Masten says. “Driving across a driveway with a front-end loader can do some damage.”

The engineering crews that erect the flood protection barriers now carry GPS-enabled digital cameras with them on each job. They take photos of every property that is affected by the temporary construction projects before and after, even if there is no damage. Back at the office, the photo-mapping software matches geotagged photos to the correct parcels in the city GIS. The documentation helps prevent against fraudulent property damage reimbursement requests.

Engineering crews also snap photos of the levees and embankments they build, and compare the photos against resulting flood damage in specific areas to assess how well the structure and its materials performed in keeping out water. As local governments begin to use photo-mapping for documenting disasters and for ordinary maintenance needs, other uses for the technology are sure to emerge.

Kevin Corbley is a geospatial business consultant.