Jan. 25, 2020 — Waterways are essential to the survival of humanity. The successful movement of people, food and goods has been central to the exponential increase in the number of humans on the planet and in the geographic area we control as a species.
The need to maintain the ports and estuaries which allow for the transport of goods from one place to another is critical in maintaining the quality of life people have come to expect, not only in America, but around the world. Here in Florence, there has been a growing realization that the accessibility of the Port of Siuslaw has been diminished and is now a deterrent to visiting ships.
The primary method used to clear away the sediment and debris that are the main impediment to safe navigation in and around America’s ports is dredging, which has been documented as a technique used for clearing waterways for more than 6,000 years.
Tacitus, a historian during the reign of Nero, discounts the story of Nero burning Rome but does commend the disgraced leader for clearing the debris left after the sacking of Rome using elementary dredges.
Leonardo DaVinci designed a dredge known as the “Draga Cavafango,” or the Mud Dredger, which has been adapted for current needs and is produced and used in Italy. Designed to clean the beds of harbors, lagoon canals and locks, the Mud Dredger is placed on two boats and has four revolving paddles operated by a crank. The shape of the dredge channels the falling mud into a raft, which is moored between the two boats.
One of the most important factors to consider when discussing water transport is water depth. The depth of the channels and rivers that lead to ports and docks are affected on a daily basis and impacted by a process called siltation.
According to Marine Insight, the issue of siltation has been a problem for ship captains since sea trading began thousands of years ago.
“Silting, the natural phenomenon of deposition of silt and sediments over the seabed, created a constant threat to the voyages of ships. People started fighting with the problem of siltation to ensure the safety of voyages but, due to lack in equipment for removing siltation, they started manual digging up of the mud by hand which was not that efficient and limited to shallow waterways.”
Marine Insight reported these other important aspects of dredging.
The Port of Siuslaw is currently in the process of dredging the main docking areas for the facility, which has experienced a marked decrease in visitors using watercrafts during the past five years. One of the reasons for this decrease may be the inability of larger, live aboard vessels to safely navigate the Siuslaw estuary.
There are also fewer recreational crafts using the docks at the port and this is almost certainly due in part to boat owners’ inability to confidently enter and exit the Siuslaw River and the waterway leading to the docks.
Port Manager Dave Huntington has been focused on dredging the port since before he was hired by port commissioners two years ago to manage the facility. Huntington is an angler and has worked as a charter boat captain, based primarily in Florence.
He is familiar from his own experiences with just how critical deep, clear waterways are to the recreational and commercial boaters.
“I started working on this project pretty much as soon as I started here. It had been eight or 10 years since we had the port dredged and it just wasn’t as safe as it probably should be,” Huntington said. “It took us awhile to get the paperwork done. We were working with the Army Corps of Engineers and working with the company in Coos Bay to schedule us, but we are getting it done and I think it will make a big difference.”
The primary piece of equipment used to clear silt is the dredge, but because of the many different situations that occur in and around the waterways where ports are located, there are different types of dredges. The dredge being used at the port is known as a suction dredger. These dredges operate like a giant vacuum, in this case with a screw-like auger at the front of the dredge, which loosens compacted silt and dirt before sucking it up and pumping it through a series of long pipes to the location of the debris pile.
The distance the pipes need to run depends on how far from the water being dredged has to be transported before being deposited. In the case of the Port of Siuslaw, the debris lines will run to the east end of the property, where debris will be deposited.
There are also negative aspects of dredging that are inherent to the process, such as the creation of major disturbances of aquatic ecosystems. These disturbances often negatively impact the marine life in the area that is dredged. There is also the likelihood of uncovering heavy metals and other industrial based toxins that can adversely affect the formation of hard-shelled mollusks and other sea creatures and spreading them to other areas.
The danger of this type of contamination is behind a requirement in the U.S. Clean Air Act that mandates all discharge locations from a dredged site must be approved by the Army Corps of Engineers, which was done in this case last year.
The end result of the dredging the Port of Siuslaw, which should be wrapping in the next two weeks, will allow for the passage and docking of larger vessels and with those, tourist dollars spent in Historic Old Town Florence, at Three Rivers Casino Resort and in local stores, as well as those recreating in “Oregon’s Coastal Playground.”