Disastrous event results in beneficial tool

The winter of 1997 pounded Grand Forks, N.D., with a series of blizzards that deposited 100 inches of snow in six months. Snow piled so high on the city’s flat landscape that the roads became like tunnels, walled high with packed powder on either side.

In April, the weather warmed, and then the trouble really started. Melting snow poured into the Red River, causing the river to rise quickly to flood level (28 feet) and creep toward the edges of Grand Forks. The water crested at 54 feet, bursting past sandbags and dikes, and engulfing the downtown business district and beyond.

Two million acres of farmland were flooded; 8,600 homes and 1,600 apartments were destroyed or damaged; and the city did not have drinking water. Forty-six thousand people (90 percent of the city’s population) were evacuated.

When the flood receded, the city began rebuilding with the help of $350 million in grants from the Federal Emergency Management Agency (FEMA). Among the grants were $1.2 million for a Geographic Information System (GIS) that would help officials fight the next flood and serve the city on a daily basis.

Gathering data

To build the GIS, city staff members collected digital files of maps and utility drawings that survived the flood. They also scanned all of the city’s remaining paper and vellum maps — some dating back to the 1890s — and converted them into digital files.

In 1999, Grand Forks purchased GIS software from San Rafael, Calif.-based Autodesk and contracted with locally based Advanced Engineering & Environmental Services to redesign the city’s sanitary water and stormwater systems, and to help the city develop the GIS. Grand Forks also purchased a server to make maps, drawings, photographs and tabular reports available to employees via the city’s intranet.

Working under a 20-month deadline — after which federal community development grants would expire — consultants and city employees gathered and integrated data such as geographical maps, property plats, tax assessor’s plans and underground utility networks. The consultants created a “base map” to serve as the foundation of the GIS, and they trained city employees to update and enhance the system. “Our contractors helped establish the GIS for us, but we wanted a system that we could manage ourselves and shape into exactly what we wanted,” says Adam Jonasson, the city’s mapping and design coordinator.

While the GIS took shape, disaster recovery money allowed the city to collect new spatial data. For example, staff members surveyed Grand Forks’ rebuilt utility infrastructure with Global Positioning System (GPS) devices. The survey data allowed the city to add centimeter-accurate drawings for drinking water, sanitary water and stormwater pipes to the GIS. The city also took new aerial photographs of the city and surrounding areas.

The city re-surveyed each of its half-square-mile sections and quarter sections with GPS. It also installed nine new geodetic control monuments at various points, which were registered with the U.S. Geological Survey.

The new survey provided a precise frame of reference for officials when they began to map the city’s new flood dikes. It also helped the city create topographical map layers (accurate to one foot) showing the city’s contours and elevations.

In addition to creating map layers for land topography, the city included in the GIS a pavement map that links to road surface maintenance reports and street-level photographs; a property parcel map; zoning information; street signs and traffic signals; and water features such as valves, hydrants, catchbasins and manholes.

Helping with daily tasks

All of the city’s map and photographic data share a common coordinate system, which allows employees to pinpoint the same location in different layers, whether in a pipe diagram, a terrain map or an aerial photograph. The software can import AutoCAD files and other kinds of file formats without losing accuracy. “That was important to us because our property parcel maps, zoning and pavement data are in a non-AutoCAD format,” Jonasson says.

Eight city departments routinely use the new GIS. Employees can query the system to find concrete pipes versus plastic pipes, for example, or all the valves of a certain kind that were installed in a given time span. “Before, we had no fast way of knowing how many pipes fed into a particular lift station; now we can total up all the feet of pipe for each area. So if the Wastewater Department is cleaning [pipes], it can assemble information for a cost projection or a maintenance plan much more easily than before,” Jonasson says.

Staff members using the water layer can click on any valve and view the maintenance record showing the last time the valve was flushed, or they can view the as-built drawing from when the pipe was initially installed or replaced. “Everyone appreciates [the GIS] because it’s a very visual, intuitive way to find utility systems and the records associated with them,” Jonasson says.

In the property parcel map, clicking on a parcel brings up a photo of a particular house and the latest assessor’s report — data that is stored on a separate IBM AS/400 file server. On the traffic layer, the city’s electricians can click on any traffic signal and view a history of the maintenance on that specific signal and a photograph of it, which is stored in an Access database.

The plans for the permanent flood protection system are in the GIS; so is FEMA’s 100-year floodplain map showing vulnerable areas. The GIS also holds a “closure document” indicating specific points where dikes would be closed across roads and railroads in the event of a flood. The document shows parts of the stormwater system that would be closed and pumps that would have to be activated.

Fighting floods

Shortly after Grand Forks developed its GIS, the city got a scare when, in March 2001, large amounts of snow fell in the Red River Drainage Basin. The river once again began to rise, and Grand Forks went into its “flood fight” mode. Jonasson was posted at the police headquarters and the city’s Emergency Operations Center, where he and other staff members accessed the GIS via PCs.

The GIS’ topographical layer showed how the rising water could affect surrounding areas. Based on that information, employees used the GIS’ mail-merge function to assemble lists of property owners so the city could ask for permission to build temporary dikes on their property.

“The GIS was only a month old at that point, but it was a great tool for us because it was information we’d never had at our fingertips before,” Jonasson says. “Citizens would call in, worried about the risk to their house, and we could zoom right to their address, turn on the [topographical] elevations, tell them the elevation in their lot, then compare that to the river profile in their area. We would tell them that the river had to get to a certain height before they’d be in danger. It gives people peace of mind. We probably took 800 calls like that.”

Planning ahead

Jonasson expects that a version of the GIS will be available to the public over the Internet within two to three years, so residents will be able to check property elevations and other information on their home computers. The city also wants to make the GIS available to field staff on wireless devices so they can use the data in non-crisis situations.

“Ultimately we’d like our maintenance folks to have water data on their iPAQ when they’re out on a job,” he says. “We’re putting all the [details about a water pipe’s installation] into the GIS now. So [staff members] will be able to click on a valve and see that it was built in 1940 and requires 15 turns to close it.”

By creating the GIS, the city has armed its employees and residents with tools to better respond to future catastrophic events. In the meantime, the information is improving the city’s response to daily tasks.

Chad Mills is vice president for Autodesk Government at Herndon, Va.-based DLT Solutions.