Special report: Clio Bay cleanup: Controversial, complicated and costly
The forest industry has been operating on the Pacific coast from Oregon to Alaska for more than a century. Over that time, it is likely that millions of logs from booms and other operations have sunk to the bottom of bays, cove, estuaries and inlets along the coast.
During that century, scientists in both Canada and the United States have been studying the effects of the those sunken logs on the sea bottom. It is only in recent years that the cumulative effect of all those logs has become an environmental concern.
As well as logs on the sea bottom, ranging, depending on location, from a couple of hundred to the tens of thousands of logs, there are wood chips, wood fibre and discarded log parts and bark. Often metal cables, bolts, ropes, and other manufactured material either dropped accidentally or deliberately discarded are also found among the old logs, further contaminating the seabed. Compounding the problem of the sea bottom is organic material that would occur naturally on the seabed, including tree trunks, roots, branches, conifer needles, deciduous leaves and other material from terrestrial plants.
Anyone who sails Douglas Channel after a storm can see with all the floating tree trunks in the Channe. That means that storms and spring run off ads debris to the natural pile up of old logs and debris. At logging sites, this natural material, brought in by creeks and rivers, piles up on the already sunken logs.
Over the years, depending on the salinity, teredos, more popularly known as ship worms eat the wood, often leaving a tube of bark that eventually collapses. The rotting wood, bark and other material is often, depending on conditions, pounded into fragments by the action of waves, currents and outflow from rivers. Some species of teredo can live in brackish water, but since teredos are not a fresh water species, that means that logs in fresh or mostly fresh water last longer.
A DFO report on sunken log sites on Douglas Channel, published in 2000, noted:
very few comprehensive, quantitative field studies describing the effects of wood and bark have been published and those that did focused on log handling and storage sites which handled high volumes of more than one million cubic metres.
The DFO report said that thick bark and wood debris deposits resulting from log handling can cause substantial, long-term negative impacts to benthic (sea bottom) ecosystems. Under the worst conditions, the cumulative debris can deprive an area of oxygen and, according to DFO, “virtually eliminate aerobic” sea bottom animal life.
The report noted that studies had shown that “negative biological impacts were localized,” but added that “the cumulative effect of several hundred sites located on the B.C. coast is currently unknown.”
Studying the problem has been a low priority for DFO and other agencies and that meant a limited budget and few studies. Other problems is that, according to the DFO, parts of BC fjords are steep and “much of the likely impacted habitat is beyond diver range.” There is also pressure to study the effect on “economically or socially important species.” Although the use of remotely operated vehicles has increased since the 2000 report, using an ROV can also be a budget buster for a low priority project.
As the ready timber supply in British Columbia particularly old growth forest declined in the last part of the twentieth century, the DFO report says “forest companies have harvested areas where access is more difficult and cut-blocks are smaller.” That meant many smaller dump sites were developed that were used for only one to five years. Plans for log handling at the time, DFO said, were evolving to ensure ensure that fisheries resources and overall fish production capability were not adversely affected by development of log handling facilities and planning was focused on ensuring that sites for log handling facilities did “not have sensitive fish habitats or fisheries resources (such as eel grass beds or shellfish resources) which may be affected by the log handling,”
One of the reasons for the disagreements over Clio Bay is that while some people call it “dead” saying there are no halibut and fewer cod, others say that Clio Bay is very much alive, pointing out that it is easy to catch crab and rock cod.
The studies that have looked at life on the bottom of log dumps sites have shown that it can be highly variable even within one bay or cove, with many factors creating small local ecosystems, including depth, nature of the sea bottom, for example sand, mud, clay or a mixture, whether or not the sea bottom sediment is “enriched,” the flow of currents, fresh water flow into the site, the percentage of wood on the bottom, the percentage of bark on the bottom, whether the wood and/or bark debris is “continuous’ or “discontinuous,” whether or not the seabed is contaminated as was the case with the cleanup of pulp mill sites at Ward Cove and Sitka, Alaska.
Ward Cove had been so polluted for decades by pulp mill effluent that it was eligible for US Superfund clean up funding and was estimated to hold 16,000 sunken logs. At the same time, an EPA report on Ward Cove noted that at the point Ward Creek emptied into Ward Cove was “a popular sport fishing location during salmon season, including commercially guided fishing. Some sport fishing and personal-use crab pot fishing has taken place in the past and may continue in the waters of the cove.” At the same time of the cleanup, the EPA identified that the degradation of Ward Cove put at risk eight species of salmon, 75 “non-salmonid esturine and marine fish species and benthic invertebrate fauna.” (The EPA says Ward Cove is recovering after the reclamation and fishing is continuing)
In other words, those say Clio Bay is in danger and those who say Clio Bay is a rich source of life are likely both right.
For example, while Chris Picard’s (then with the University of Victoria, now with the Gitga’at First Nation) study of Clio Bay said: “Dungeness crabs were observed five times more often in the unimpacted Eagle Bay than in Clio Bay,” and tied that to log dumping and low oxygen.
Picard’s study noted that both Dungeness crabs and sunflower seastars, while more abundant in Eagle Bay, in Clio Bay “both species were several-fold less abundant in wood-dominated habitats in Clio Bay than in non-wood habitats in that bay.”
Several people have pointed out that since Clio Bay is one of the closest crabbing spots to both Kitimat and Kitamaat Village, while Eagle Bay is further down Douglas Channel, overfishing at Clio may be a factor in the reported species decline.
The DFO study noted
The dumping of logs into water down skids can result in the generation of a considerable amount of bark and wood debris. The abrasive action of boom boats and waves during the sorting and storage of bundles can also generate quantities of wood debris. Bark and wood lost during dumping often forms thick, continuous, anoxic fibre mats extended from the base of the dump skids. The debris mat tends to dissipate with distance from the entry point; however, wood debris can often be observed substantial.” distances from the dump skids as seen at all four of the sites sampled. Debris deposits can also be generated as logs resting on the sea floor decay. Wood boring organisms (e.g., Toredo) quickly reduce the wood fibre content of logs, but the bark of some species (e.g., western red cedar (Thuja plicata) which has a high lignin content) is left relatively untouched. The amount of wood debris generated during handling and storage can be different depending on tree species, tidal levels, and dumping methods. Debris accumulation, distribution, and the resulting biological impacts are affected by physical factors including depth, sea floor slope, dump site aspect, water currents, and wind or wave exposure.
One of the main problems with log dumping is that it has the potential to deplete vital oxygen, especially at deeper levels. Seasonal variations can mean that, even if there are thousands of logs at the bottom, the levels of dissolved oxygen can vary. Years of studies at the cleanup site at Ward Cove, Alaska showed how the oxygen levels can vary by season. In Minette Bay, near Kitimat, a DFO study showed that the Minette is somewhat stagnant and therefore has naturally occurring low oxygen levels, but also that the low levels usually last from May to November and are worst in July.
The DFO study went on to say that oxygen poor thick anoxic bark or wood fibre deposits are likely to cause damage to bottom dwelling species, although in the short term, logs may not cause any impacts. It says that some studies have indicated that large pieces of wood debris can, for a time, increase diversity by providing suitable base for some filter feeders as well as food and cover for epifauna and wood boring organisms. Several species not normally found in sand-bed have occasionally been found in log and rock debris.
(Studies have shown that salmon the ability to detect low oxygen areas and avoid them and some active invertebrate species can migrate away from a low oxygen area.)
In the long term, logs do decay and the wood and bark left behind can contribute to the wood debris accumulation. One study cited by the DFO survey of Douglas Channel found found that crabs avoided bark deposits when given a choice but when they were forced to live among bark deposits, they were had fewer offspring, had lower feeding rates, and had a decreased survivorship.
One theory is that the decaying organic material produces hydrogen sulphide in combination with ammonia and other unmeasured toxicants. One study of Dungeness crabs, living at a log dump in southeast Alaska with elevated hydrogen sulphide and ammonia concentrations in the bark debris, shows the colony had less than half as many reproducing females as a control population.
The EPA and Alaska reports from Ward Cove show that sand capping does help restore the seabed environment.
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