A Magical Island Kingdom ™
The Grade Raising
Could the City of Galveston have survived with only The Seawall and no Grade Raising? If the entire city had been encircled by a 17-foot-high concrete seawall, it would have been protected, but life would have been lived inside a deep bowl, with the residents straining to see out over the rim. Views of the Gulf, the Ship Channel and the Bay would have been lost at ground level.
That such a design would have been prone flooding would be an understatement. Like New Orleans, and its levies, Galveston in a such a configuration would need a massive pumping system to remove rain water, and any tidal surges that over topped The Seawall. If the pumps failed, residents might be living in chest-deep water for an extended period of time. Like The Seawall, the decision to raise the elevation of the City was a godsend!
Fortunately, The Grade Raising was an integral part of the recovery plan after the 1900 Storm, so building a seawall by itself was never even considered. Once The Seawall was finished, a method was needed to bring in fill to raise the elevation of the area that it enclosed.
The Grade Raising was a much more complicated, complex and expensive engineering project than building The Seawall. The Seawall was built on open land, with nothing to interfere with its construction. The Grade Raising had to be done between and around thousands of existing structures, and miles of infrastructure.
The Seawall was completed in a little less than two years for $1.6 million. The Grade Raising was projected to take about three years and cost $2 million. It actually took over 7 years and cost $3 million.
Engineers P.C. Goedhart and Lindon W. Bates proposed dredging sand from the harbor channel with self-loading hopper dredges, and then bringing the sand onto The Island using a canal cut through the City. Then the slurry of sand and water would be pumped off the dredges, through pipes, and in what seems like crazy space games the sand and water would end up in the desired locations.
The partners received a contract to implement their plan and supply 11 million cubic yards of sand over a three year period; and the work began.
The first step was to dig the canal. The digging started near where 8th Street met the harbor channel. The work proceeded south, parallel to the the eastern portion of The Seawall that was built along 6th Street. As it approached the Gulf, it turned west, at the 6th Street turn in The Seawall, and then ran right behind The Seawall at an angle until it hit 22nd Street. From there, it more or less followed Avenue P out to 33rd Street. Any structures in the path of the canal had to be moved, and replaced later when The Grade Raising was completed.
The dredge boat "Holm" (center) dredging
the canal near UTMB in 1904.
When finished, the canal was two hundred feet wide, twenty feet deep and three and one half miles long. At the beginning of the project, this seemed to be an adequate water way, but eventually it proved too small for the largest dredges that were employed. Even though precautions were taken to prevent the canal from filing in, there were recurring problems with crumbling canal banks and silt which required regular dredging to keep it open even for the smaller hopper dredges.
The first dredge to arrive was the "Holm". It was later joined by "Leviathan", "Triton" and "Nereus". All of the hopper dredges used in the project were built in Germany.
A drawbridge was built at 23rd Street, to keep traffic moving across the canal, and turning basins were constructed between 13th and 15th Streets near Avenue N 1/2 and between 31st Street and 33rd Street at Avenue P 1/2, to allow the dredges to more easily return to the Harbor after discharging a load.
Wooden bridge over the canal at 23rd Street.
Square sections of the City, 1320 feet on each side, were enclosed with a dike, and then everything within the dike was raised to the desired height. The City paid the cost of lifting the existing infrastructure: gas and water lines, electric and telephone poles and wires, and streetcar tracks. However, each owner had to bear the cost of raising their own structures.
Most people chose to raise the elevation of their houses and commercial buildings to the requested height, but some left them in place and let the slurry partially bury them. Ashton Villa and the Samuel May Williams House are two properties that were not raised. You can still see where the fill partially covered them.
Houses and other buildings were lifted using hundreds of jackscrews that were ratcheted up 1/4 inch at a time. In total, workers raised 2,156 structures, of various kinds, from a few inches to as much as 17 feet. The most massive structure raised was the 6 million pound, stone and brick, St. Patrick's Church, which was lifted five feet using 700 jackscrews. However, there were other churches and public buildings which were lifted that were almost as big and heavy as St. Patrick's.
Some people even tried to raise gravestones and trees, but these efforts were largely unsuccessful. Most of the trees, and other plants, that were elevated, died and had to be replaced. However, with the proper effort, it was possible to save the top soil on a piece of property, which made re-planting much easier.
When everything was repositioned at their new height, the dredge would move to the nearest discharge station and begin to pump its slurry of sand and water through 46" pipes into the partitioned area. It took awhile to fill up each square, and then more time for all the water to drain off and leave relatively dry sand. During the process, the residents built wooden boardwalks high above the slurry, which allowed them to walk from the street to their houses, and from one house to another, as they contended with the smell, and the flys that the fill attracted.
Large dredge (middle left) anchored at discharge station.
Pipe runs down a gang plank, across the dike, where it splits
into a Y and discharges the slurry inside the partitioned square.
The houses in the partitioned area have been lifted
above their original height, on wooden stilts, and an
elevated boardwalk leads from the street to the house,
as the slurry is discharged to fill in under all these structures.
When one area was done, a new square was surrounded by dikes, and the process began all over again.
Towards the end of the project, Goedhart and Bates had a falling out, due to the $400,000 they had lost at that point, so the North American Dredging Company had to finish the job by dredging sand from Offatt's Bayou. When the work was completed, in 1911, an astounding 16,300,000 cubic yards of sand had been added to the land mass of the City!
Slurry discharging in front of houses.
Close up of slurry discharging, with boys watching.
Moving pipe to a new location.
Raised houses and elevated boardwalks
at the beginning of the process.
The Galveston History Center
The 1900 Storm-Rebuilding
Raising the Grade