Computerized System Helps McCarran Track Underground Utilities

Las Vegas McCarran International Airport has grown considerably as it struggled to keep up with a skyrocketing tourist trade and the city's ever-growing population.

The airport expanded through a series of planned major projects and a plethora of additional add-on buildings. This made keeping track of the blueprints and other documents depicting the exact location of various utilities a frustrating, time-consuming effort. During an emergency such as a water main break or a severed power cable, airport staff would have needed to sift through hundreds, if not thousands, of documents to find the right schematic to find the closest shut-off valves or relay switches.

Las Vegas McCarran

These days, the information is available to authorized personnel with a few quick keystrokes. But it didn't come easily - the project took five years and cost $1.6 million.

Preliminary efforts actually began in 1995, when the airport added an in-house geographic information system (GIS) to manage its spatial data. The new system, with staff to use it, made tracking utilities around the airfield much easier. Five years ago, McCarran began the ambitious effort to compile every paper map, film and mylar related to utilities into a single, centralized electronic GIS database.

Kennedy/Jenks was contracted to sift through all the historical drawings from every airport construction project and enter them into an electronic database. Steve Stretchberry, a consultant with Kennedy/Jenks, estimates the company processed more than 10,000 different drawings. "It was a time-consuming process, but the technology evolved to a point that the data is now much more useful," he says. "In some respects, the final product wound up being smarter than we expected it to be going into the project."

Facts & Figures Project: Computerizing data about location of airport utilities Location: Las Vegas McCarran International Airport Contractor: Kennedy/Jenks Cost: $1.6 million Project Duration: 5 years Key Benefits: Quicker access to more accurate information about underground utilities; cost savings incurred by tapping into existing utilities for future projects

Building on a Foundation

The project started as a utilities master plan in 2003. Data gaps and conflicting documents from 55 years of projects had created uncertainty about the exact location of some utility lines. The project was limited to utilities up to building exteriors because interior schematics are located on architectural drawings.

Kennedy/Jenks staff began with a baseline document of what the physical plant of the airport looked like. Because that document was produced in 1981, they considered it a foundation for data about 60 other projects completed in the 24 years since it was compiled.

The staff worked in reverse chronological order, capturing information about existing facilities first, because much of that data was already in AutoCAD format that could be transferred more easily into the new system. Technicians then filled in gaps with older data.

Compiling the data was a daunting task, says Samuel Ingalls, McCarran's assistant director for information systems. "We literally had mountains of paper and drawings that may not have been updated as they should have been as various projects were finished," he explains. "The process of manually locating specific utility lines was time consuming and sometimes not as accurate as it could have been."

Consequently, once the maps were digitally incorporated into the database, Kennedy/Jenks staff physically verified and documented any visible above-ground locations within the airport using global positioning systems and digital photographs - effort that added real value to the project, according to Ingalls.

For example, construction crews paint or flag areas to mark the location of underground utilities. But multitudes of changes to utilities over the years sometimes mean that the paint or flag offers little reassurance that there aren't other utilities from different projects drawn on different maps.

"That's often why a backhoe hits a water line," explains Ingalls. "It's not that the crew didn't do the appropriate marking; it's that that person doing the marking may not have factored in all the projects that have taken place in that area. The backhoe operator thinks the water line is in a certain place and is always surprised when a geyser erupts 10 feet from where he expected the line to be."

Even though a map may show a particular utility line coming into a specific place, last-minute changes during construction may have moved the line as much as 20 or 30 feet from the location shown on the map, notes Ingalls. Over the years, airport staff involved in construction projects simply "remembered" the last-minute changes and where some lines were moved. But, keeping track of precise locations became even more difficult as those people retired or more projects were completed.

Aiming for Accuracy

The accuracy of McCarran's new system was verified at three levels, says Jeroen Preiss, lead GIS technician with Kennedy/Jenks. First, data was checked by another person as it was entered into the system. Second, the firm hired an airport veteran with engineering experience to check the data and add institutional awareness, such as knowledge of last-minute changes to original plans. Finally, staff walked the airport to verify that lines were exactly where the system said they should be.

According to Preiss, McCarran invested enough time and effort into verification that the system can produce horizontal accuracy to within eight inches.

In compiling the data, project engineers also tried to zero in on information that was relevant to particular circumstances. The new GIS system is networked to associated data.

For instance, if there's a water leak, it will identify the nearest shut-off valves. "That way, nobody would need to look at the drawings; they would know immediately where to go to fix the problem," explains Preiss. "They wouldn't have to evacuate the building, and crews could respond in 30 minutes instead of half a day."

The five-year project was implemented in several phases. Officials expect to accrue significant cost savings from operational efficiencies to offset its cost.

"Now that we have a good digital baseline, our staff can continue to incorporate the newest electronic project data into our GIS database to keep the system current," says Sonya Wilson, senior GIS analyst for the Clark County Department of Aviation. "Incorporating utility verification survey data will only improve the database accuracy in the future."

Keeping the information updated will be simple, too. If field workers discover an error in the data, or make changes to plans during construction, updates can be quickly added to the GIS records for future reference.

The system's on-line application allows users to zoom in on specific areas and show different GIS layers. So, rather than seeing the entire utility grid, workers can call up just the electrical layer. Or, if they want to look up a specific project, they can see all the other utilities in a particular area, Wilson adds.

Users can also click on any electrical line and see its associated project number. Then, by clicking on the project number, they can access all the original utility record drawings associated with the project. If users want information for a specific sheet, they simply click on the drawing.

"People will only use something they find easy to use," notes Ingalls. "If it's challenging to learn, or if it is something you forget how to use because you haven't accessed it in a while, it will be more difficult to get people to use the system. That is not the case with the system we developed."

According to Les Chau, a principle geologist with Kennedy/Jenks, other airports could benefit from similar geographic information systems. Knowing the location of active and abandoned utility lines, he adds, is especially important for facilities that evolve through a hodgepodge of buildouts and demolitions. It's also important to realize when one line comes into a building and another line comes out - especially during emergencies such as destructive weather.

"Many airports have all the infrastructure of a small city," Chau notes.

The new system is also a "great springboard" for construction sequencing over existing facilities, adds Preiss. This sometimes allows airports to optimize new facilities by tapping into existing lines rather than bringing in new services.

"This kind of technology democratizes information by distributing it to staff at all levels so they can participate in decisions," adds Chau. "Management doesn't try to make decisions by itself, but can involve staff at all levels to provide input from their area of expertise. Present business models have found that this type of collaborative decision process, facilitated by a web-based geodatabase system, results in much better project outcomes."