Turbidity revives old debate

Environmental activist Will Koop has claimed that he found two major sources for the turbidity of Greater Vancouver’s water supply. Both sites were in an area that had previously been logged near the Capilano reservoir, which recently recorded turbidity levels 70 times higher than what’s considered acceptable under B.C.’s drinking-water regulations.

On November 21, GVRD staff escorted Koop, coordinator of a citizens’ group called the BC Tap Water Alliance, into the watershed for an inspection. Afterward, Koop claimed to the Georgia Straight that he observed “thick brown” water in Sisters Creek and Strachan Creek, which connect below the twin peaks known as the Lions. He added that there was “brownish” water also flowing in the mideastern section of the Capilano River. Both sources flow into the Capilano reservoir.

“That’s the area where all the logging was in,” Koop said. He added that the Capilano Logging Company removed trees in the Strachan Creek area in the late 1920s, whereas the eastern part of the Capilano River was logged after 1968.

Koop noted that the first water-district commissioner, E.A. Cleveland, halted logging after the region took control of the watersheds in 1927. Later, Cleveland declared, “They will log that watershed over my dead body.”

In the 1960s, several years after Cleveland’s death, the GVRD began logging, claiming it was necessary to reduce the likelihood of forest fires. The GVRD halted almost all logging in the watersheds 12 years ago.

One of Koop’s critics is Rob Kyle, a member of the GVRD’s Regional Water Advisory Committee. Kyle described Koop’s claim about Sisters Creek as “meaningless” without a scientific examination of the source of the silt. “How can Mr. Koop provide any sort of rationale that logging is to blame when those areas have all been reforested, and they have a solid mat of trees and vegetation holding the soil in place?” Kyle told the Straight.

GVRD chief administrator Johnny Carline told reporters at a November 17 news conference that Greater Vancouver’s turbid water is not linked to previous logging in the watersheds. (See sidebar.) GVRD spokesperson Bill Morrell told the Straight on November 22 that a flight over the watersheds revealed 37 separate landslides. Most of the slides were closer to the Coquitlam reservoir, which was less affected by turbidity. “Our overflight indicated all or a vast majority of these occurred in areas that were not affected by logging,” Morrell said.

UBC forestry professor emeritus Peter Pearse chaired a GVRD scientific-review panel on watershed management in the late 1990s. He recently told the Straight that the “overwhelming” cause of turbidity is slippage of lacustrine [fine silt] deposits, which form at the bottom of lakes. “Those areas up in those watersheds used to be lakes in the glacial period many years ago,” Pearse said.

He added these silts slide off the mountains during heavy rains, which are common in November, and they keep hanging in water. In 1999, the Straight reported that Pearse had told the GVRD water committee that his panel did not investigate the impact of logging and road-building on drinking-water quality.

Western Canada Wilderness Committee campaigner Joe Foy told the Straight that mudslides are twice as common in forests that have previously been logged than in old-growth forests. “There’s an old saying, ”˜If you can’t set a good example, you’ll just have to be a horrible warning,’” Foy said, referring to Vancouver’s drinking water. “I think that is the function Vancouver is playing right now.”

However, Foy also cautioned that until he is able to fly over the watersheds on a clear day and look at the evidence, it is still too early for him to declare that logging is the cause of all that cloudy water coming out of the taps in November.