If a few thousand put-upon but determined citizens succeed in their latest bid to tear it down, however, their victory will resonate far beyond the headwaters of the Humber, potentially ringing bells through all the ravaged borderlands of New Jersey North. And they're closer than ever.

Their latest ally is a respected professor of public health at the University of British Columbia, Richard G. Mathias, who has filed an affidavit in support of their coming lawsuit, telling the Ontario Superior Court that the fence is a crock.

The waters of the little creek present "virtually no risk to any person's health," Dr. Mathias said in a long brief that investigates -- and methodically demolishes -- the evidence that first inspired regional health officials to fence it off. Furthermore, he added, there is no evidence that local septic systems are polluting it. Dog turds and runoff are more likely causes.

King citizens have long suspected that their local "health hazard" was trumped up -- invented, in a word -- to justify the construction of a massive sewer pipe capable of quintupling their village's population and destroying its character. Dr. Mathias, a top Canadian epidemiologist, didn't go that far. But his scathing review of the health evidence does effectively destroy the fundamental rationale for the plan to build the notorious, sprawl-spewing Big Pipe.

Dr. Mathias concluded that Helena Jaczek, the former York Region medical officer of health who first declared the "hazard," currently a Liberal candidate for the provincial parliament, "has failed to follow the accepted approach to identifying risks to public health . . . and has identified as significant a risk which the literature familiar to me says is very low."

Not only did Dr. Jaczek err in declaring a health hazard where none exists, Dr. Mathias added, but she was also wrong to conclude that E. coli bacteria in the river originated in human waste, wrong to conclude that it came from leaking septic systems and wrong to conclude that the risks from leaking septic systems are increasing.

In other respects, the B.C. professor, former director of field epidemiology at the Laboratory Centre for Disease Control in Ottawa, simply repeats observations of "inconsistencies" that many skeptical citizens have made, especially the fact that for years local health officials did absolutely nothing to remedy the alleged "environmental health hazard" they had identified.

They did, however, strongly advocate construction of the Big Pipe, promising that it would solve the alleged problem while ignoring the fact, as Dr. Mathias points out, that rivers in parts of the region already serviced by the pipe -- i.e., already suburbanized -- are contaminated "at much higher levels" than the Humber in King City. Even the Humber is more contaminated above and below King City than it is in the vicinity of the supposedly lethal septics, Dr. Mathias pointed out.

It's no wonder, then, that regional officials have lately proven so keen to settle their dispute with the township council before the two sides meet in court next week. (King Township is suing York Region to regain control of its sewage fate, which the region took over when town council attempted to kill the Big Pipe.) York's position is weakening by the day.

Currently the biggest fear among antipipe environmentalists is that council will accept a settlement calling for a scaled-down pipe, but even that would be a significant victory. This stubborn battle has already made it clear that the old ways of New Jersey North -- forcing urban sprawl by running oversized sewer pipes through every green hill and dell -- are finished.

jbarber@globeandmail.ca