GPS Bahrain

A GPS-Guided Survey in Bahrain in 1993

Guided by a signal from outer space, each step over the desert sand brought us closer toour goal.  At my side were Dr. Robert Killick, of the London-Bahrain Archaeological Expedition, and his neighbor in Bahrain, Nick George.  We were searching for one of the oldest sites in the island state: an Ubaid encampment dating to c. 4,000 B.C.   In my hand was a Global Positioning System (GPS) receiver.  It was the first time any of us had used it in the field.  The screen displayed the distance between myself and the longitude/latitude coordinates previously entered into the receiver's memory.  The unit's direction finder kept our course straight.  We wondered what we would find at the path's end.

Earlier that day we had gathered around Killick's Land Rover.  Killick, George, and myself were joined by Dr. Jane Moon, Killick's wife and partner in the London-Bahrain Expedition; and Emily and Katie, their young daughters.  With the kids in the rear jump seats, we headed south down the highway, turning off onto desert pathways somewhere near the Ubaid site.  Once on foot, our destination seemed tantalizingly close.  We enthusiastically marched over the gently rolling dunes only to be stopped by a chain-link fence enclosing a camel herd.  Somewhere beyond the perimeter lay the Ubaid site.  Our objective was out of bounds.

I had become interested in GPS' role in archaeology after reading of its use in a search for an ancient city in Oman.  A team of archaeologists and explorers used GPS to find their way through the desert of Oman in their search for the fabled lost city of Ubar.  Flying by helicopter and guided by GPS, the search team was able to locate ancient caravan tracks spotted from the space shuttle Challenger.  These tracks proved to be part of the old network that linked the cities of southern Arabia.

This convinced me that GPS could also be beneficial to the nautical archaeologist.  By traditional methods, one needs to use a sextant to find latitude and longitude.  With the GPS, the press of a button finds the same data.  Hours of training in the use of a sextant are avoided and human error is eliminated, saving time, effort, and money.  In the Arabian Gulf, a featureless sea with low-lying coastal areas, longitude and latitude coordinates of wrecks are the best way to relocate wrecks once found.  Their coordinates can be easily fixed, enabling the archaeologist to return to the exact position.

Our Quest

This was my first excursion into the desert of Bahrain.  I had been conducting a shipwreck survey for the Institute of Nautical Archaeology (INA) in this Arabian-Gulf country for several weeks. With the aid of my assistant Texas A&M graduate student James Coggeshall we gathered shipwreck information from fishermen and divers as well as explored under sea.  When Killick suggested a search for land sites using GPS, I was eager for the change. 

Killick wanted to locate two sites: the Ubaid one and a shell midden associated with 4,000-year-old Dilmun pottery.  Geoffrey Bibby discovered the midden during his archaeological surveys in the 1950's, but it has never been excavated.  Both sites are located in sabkha, the sandy flats once part of the sea on Bahrain's southwest coast.  Dilmunite sailors used what was then a small island as a station for shucking pearl-bearing oysters.  The older, Ubaid site is the oldest maritime-related site known on the island.  Over 6,000 years ago, the Neolithic people of the Ubaid culture spread south from Mesopotamia to the southern reaches of the gulf.  Ubaidians could only have reached Bahrain by boat.

To locate the sites, we needed their longitude and latitude coordinates, information not published.  However, a simple map from a book showed general longitude and latitude positions for the island.  The sites were marked by dots in scale about 500 meters in diameter.  I was able to estimate coordinates for both sites, but we did not know how precisely the sites were marked on the map.  Thus, my figures contained a potential half-kilometer error.  Furthermore, the GPS signal in the gulf had been purposefully degraded to an accuracy of no more than 150 meters. Thus, even if my calculations from the map were exact, the GPS could still place us well off the mark.  We wondered if a drive through the desert would be worth the effort.

The Space Age Meets the Bronze Age

 After our attempt to find the Ubaid site, we began our search for Bibby's shell midden.  Back on the road, I held the GPS out the rover's window to get a clear signal.  The screen rapidly ticked off the meters directing our progress.  When the reading reached "0.00 m.," an alarm indicated we had arrived at the position calculated from the map.  We were again on the sabkha.  Only a few feet away a camel-racing track stretched into the desert.  There was no mound, only the white fencing around the track and the flat, shell-littered sand of the ancient seabed.  Had the midden been bulldozed to make way for camel races?  We scanned our surroundings with binoculars.  To the east were several low dunes containing no piles of shell.  More distant features blurred in the hot air rising from the sand.  Southward, beyond the far turn of the racetrack, we spotted a hillock.  It was the most prominent feature around. It was our best chance.