Clean, I don't know what QWST will do in this specific situation, but I can offer some insights as to what their alternatives are, and why they may choose one as opposed to the other...
Ordinarily if the bridge or causeway is in line with the planned cable route, it would be the most suitable path if easements or ROWs can easily be obtained.
There may be reasons, however, for wanting to submerge the cables using underwater placement techniques, such as for reasons having to do with redundancy and diversity, or when an easement cannot easily be obtained, or when using the bridge would add unnecessary miles to the route.
Any number of means have been used, but increasingly construction crews have been depending on underwater sea plows to get the job done. I had my first experience with these when the the first "Sea Plow" was used by the cable laying ship CS Long Lines in 1970 during its inaugural implementation during the placement of TAT-5 between Rhode Island and Spain.
Getting back to continental waterways and inland situations, however, before taking this approach, clearances must first be obtained from property owners and those who own the rights into the bodies of water in question (sometimes extending tens or hundreds of of meters beyond the shore point] , in the case of inland and seashore situations. Also, USGS surveys must be performed and charted.
The following two articles offer some information in this discipline, and some of the techniques used.
Enjoy, Frank Coluccio
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diveweb.com
sightings.com
The second of these is copied below, and although it runs a bit off topic, I thought that it was interesting enough to present here:
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Undersea Cables Carry Most Telephone and Net Traffic
By Mike Mills, Washington Post 3-10-98
At the water's edge of Baltimore Harbor, beneath the towering I-95 overpass that dumps traffic into the city, two freshly painted gray ships await their next mission.
Schooners moored here during the American Revolution, as did barges of the Industrial Age. But these are the workhorses of the Information Revolution: They are wiring the world to meet the explosive and seemingly limitless demand for Internet, voice and video services, which are projected to be a $1 trillion-a-year global market by 2000.
Docked at a gleaming depot that stands out amid the rusty warehouses of the harbor, the C.S. Global Link and its companion the C.S. Global Mariner are among the most technically advanced vessels in the business of laying undersea fiber-optic communications cables. They are part of a worldwide fleet, purchased last year from AT&T Corp. by Tyco International Ltd., that has installed more transoceanic fiber than any other company.
Most of the world's telephone and Internet traffic courses through these hair-thin capillaries of glass, which stretch from one continent to another along the ocean floor. In constant pulses of light, coded in the computer language of ones and zeros, they flash millions of phone calls, e-mail messages, video clips and World Wide Web pages at light speed.
Undersea fiber-optic cables have become one of the most crucial components of today's communications-based global economy, despite mid-1960s predictions that satellites would render earthbound long-distance communications obsolete.
Yet in an age of robot Martian dune buggies and livestock cloning, the marvel of undersea fiber-optics is often overlooked.
"Most people really do not have a grasp of the amount of telephone cables that are undersea, and that their calls actually go through them," said Rob Jones, captain of the C.S. Global Link.
There are 228,958 miles of fiber-optic cable lying along the floors of the world's seas, enough to encircle earth almost 10 times, according to KMI Corp. of Newport, R.I. Another 177,717 miles of cable are planned for installation worldwide by the end of 1999, KMI estimates.
And that figure doesn't count the most ambitious program, Project Oxygen, which backers describe as a $14 billion "Super Internet" that would pay out 198,844 miles of mainly undersea fiber-optic cable touching 175 countries. Oxygen already has backing by 30 international telecommunications providers and is scheduled for completion in 2003.
Project Oxygen is "the most ambitious project of communications in the 20th century," KMI President John Kessler said. "The Internet is a major driver for the expansion. The second driver is the need for video transmissions."
Kessler compares the emergence of fiber optics with such past technical breakthroughs as inexpensive and abundant paper and clean water. "Because of cheap paper, we now have all kinds of developments you would not have thought possible," from paperback books and newsprint to electronic copying machines, he said. "The same thing is going to be true of electronic communications."
Global deregulation of telecommunications markets also is playing a key role in the subsea fiber boom. No longer does "the club" of state-run phone monopolies and other giants, including AT&T and Cable & Wireless PLC, control big undersea cable projects.
Instead, phone companies abroad are rapidly going private and governments are opening their markets to competition. Chinese officials, for example, deftly played 14 competitors off each other in bids to build the first link between China and the United States -- and then ultimately told them all to share the $1 billion contract. And more than 30 companies late last month announced that Tyco would help build them a new $375 million, 5,000-mile cable linking the United States with the Caribbean and South America.
Phrases such as "quantum leap" and "orders of magnitude" frequently come up in discussions about advances in undersea fiber optics. In 1988, when glass fibers began to replace copper cables in telecommunications, people stopped talking in terms of hundreds of simultaneous phone calls per cable and started talking about tens of thousands.
Further improvements have moved the decimal place several times since. Scientists at such companies as Ciena Corp. in Linthicum, Md., have more than quadrupled fiber-cable capacity by using lasers to split light into colors, sending data through each path in a process called "wave division multiplexing."
The upshot: Atlantic Crossing, the newest transatlantic cable, can handle 2.4 million voice conversations at one time -- or hundreds of thousands of compressed video images. The China-U.S. project will handle 4 million calls at once.
And early last month, Lucent Technologies Inc. unveiled the latest breakthrough: The ability to transmit as many as 10 million calls over a single fiber, by dividing the strand into 80 separate wavelengths of light instead of 16. Lucent says the 400-gigabit (billions of computer instructions per second) speed is enough to carry the world's Internet traffic at any given time on one fiber. One voice phone call requires 64,000 bits.
It won't be long, Lucent officials said, before the industry realizes President Clinton's State of the Union address prediction that soon, "all the phone calls on Mother's Day" will be carried on a single strand of fiber. AT&T carried 145.3 million calls on Mother's Day 1997, the busiest calling day of the year.
Researchers also have found a way to avoid the need for "repeaters" that amplify fading light signals every few hundred miles or so. Repeaters slow down the information flow by converting light energy into electrical energy, then back into light again. Instead, lasers now can be used on either shore to "pump up" the signal along its way at specific points along the cable that are injected with the chemical element erbium.
Is there any limit to the capacity increases possible?
"Absolutely not," said Neil Tagare, Project Oxygen's founder and an undersea fiber veteran. "Once the repeaters go away, there is no end in sight. Even though Oxygen right now looks huge in terms of bandwidth, it's going to be a baby in five years' time. All you do is change the electronics at the shore and, boom, you have as much capacity as you need."
At the same time, the cost of fiber is plummeting. Each voice circuit in a pre-fiber transatlantic cable in 1987 cost about $40,000 annually to build and maintain, KMI's Kessler said. Today, he said, the cost has dropped to roughly $100 to $200 per circuit.
The plunging costs, combined with deregulation and competition in phone markets, have made distance meaningless in communications. Consumers on an AT&T or MCI discount plan now can pay 12 cents a minute to dial Stafford, England, from Washington any time of day, but a weekday call to Stafford, Va., costs 19 cents a minute.
Satellite companies have responded with their own technological advances. A new generation of satellites fly lower, to ease the old problem of call echo and to allow for smaller, more powerful satellite dish antennas. They can reach anywhere inland where fiber optics become more expensive to install. "I don't think terrestrial fiber will take business away from satellites," said Steven Dorfman, senior vice president of Hughes Electronics Corp., a leading satellite company. "You still have to get to the business customer."
Aboard the C.S. Global Link, Capt. Jones remains very busy. The ship returned to Baltimore in late June from the Arabian Sea and Indian Ocean, after dropping 2,000 miles of cable from Bombay to Malaysia as part of another major project, called Fiber Link Around the Globe (FLAG). Before Bombay, it helped to lay Atlantic Crossing, covering 3,557 miles of fiber-optic cables at an average speed of 6 knots over 21 days.
It takes less than two months to install a transatlantic cable. Ships use computers that are programmed to follow a specific route using global positioning satellite navigation systems. The routes are chosen after exhaustive undersea topographical surveys that consider such factors as underwater earthquake faults, canyons and shipping and fishing routes.
But the job still involves a highly skilled, yet relatively low-paid, crew.
Jones, 39, a husband and father who commutes from an Annapolis suburb, stands on call to repair breaks in cables beneath the Atlantic. On the continental shelf, a break usually is caused by a trawler's anchor that accidentally snaps a cable.
"In deeper water, it can be anything from a subsurface earthquake in the mid-Atlantic ridge or just that the cable had settled on a bad spot and is worn down," Jones said. "There is a lot of effort put into finding the reason for a fault so it doesn't happen again."
The Global Link, nearly 500 feet long and weighing 13,200 tons, packs some of the heaviest industrial maritime winches ever developed, as well as iron sea plows and robotic submarines that can locate a cable, find where it has gone bad, snap it and bring it up for repair.
Global Link can carry more than 6,000 metric tons of fiber-optic cable in its steel belly, but is nonetheless nimble enough to hover within three meters to five meters of a cable break 6,000 meters below.
There always has been more than enough work to go around for the two dozen ships like the Global Link worldwide. Still, they are about to get some competition: Project Oxygen's Tagare plans to build 59 ships to carry out his plan. Until they're built, he said, today's ships will be used.
But with or without Project Oxygen, Jones said the C.S. Global Link and other ships like it will be fully employed for years to come, as the world's land masses continue to connect along strands of glass. "It's going to get kind of crowded down there," Jones said.
The Cable Under the Sea
Underwater fiber-optic cables handle most international voice calls and Internet traffic calls (satellites handle most of the broadcast video). Each fiber-optic cable, as thin as a human hair, can carry at least 20,000 simultaneous calls. Shown is a model of the C.S. Global Link, one of the ships that lays the cable. The ship has accommodations for 138 crew, technicians and guests.
How the cable is laid
1. At least a year before the ship goes out to sea, topographical surveys are conducted to plan the cable route, taking into account such factors as underwater earthquake faults, canyons and shipping routes.
2. Over the course of several weeks, thousands of miles of cable are manually coiled into the ship's storage tanks.
3. While the ship is still anchored, the cable is floated out to the shore and connected to the shore cable station. Cable running close to the shoreline or near a continental shelf is buried in a tunnel dug by a plow.
4. Once past the continental shelf, burying the cable isn't necessary. Guided by shipboard computers that communicate with global satellites, the ship begins dropping cable, which rests on the ocean floor, four or five miles deep. Two cable engines, one in the bow and one in the stern, pay out cable at the proper tension.
5. As the cable is lowered into the sea, buoys mark the location.
6. During installation, engineers continually test the cable system, which is powered and operating as it is laid.
7. If cable needs to be repaired, a remote-control robot submarine tethered to the ship dives to the bottom of the ocean and hauls the cable to the surface, where repairs are made.
SOURCES: Tyco Submarine Systems, TeleGeography
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