"York Region is sucking water out of Oak Ridges Moraine aquifers, drying tributaries that feed the Rouge River and killing fish to make way for more development and urban sprawl," warns environmental lobbyist Jim Robb, with the Rouge Duffin Greenspace Coalition.

"It's happening because the region hasn't properly assessed the impact of construction on the environment or come up with ways to mitigate problems."

Regional officials readily admit the problem.

"We underestimated the extent of the impact to groundwater in the area," says Paul Jankowski, manager of design and construction at York's transportation and works department.

But York Region is confident it can be fixed. Officials say they have come up with new plans that will safeguard natural resources and get construction of the new York Durham Sewer System back on track.

Recommendations are expected to be tabled in the next few weeks.

King Township Mayor Margaret Black, a major supporter of the new sewer line, maintains a full environmental study isn't necessary.

Black says interest groups made three applications for full assessments and King council made one in 2000, but the minister of the environment "said there was no need for a full environmental assessment, that everything had been done properly."

The stakes are huge. New subdivisions have been approved reflecting the region's commitment to having the pipe in the ground by 2006. Halting construction for a full environmental assessment would be a legal nightmare. About 80 per cent of the line's cost will be paid through development levies.

The huge, gravity-fed sewer, which will stretch from the east side of Lake Simcoe to Lake Ontario, is being built to serve one of the fastest-growing regions in the country. With huge growth in York Region in recent years, the population is expected to almost double to 1.3 million by 2026.

The existing system, which was built in the 1970s under Yonge St. and serves Vaughan, Markham, Richmond Hill, Aurora and Newmarket, is pretty much at capacity. A new twin sewer, under Leslie St., is needed to accommodate emerging subdivisons and industries north to Holland Landing. Rural communities like King City and Whitchurch-Stouffville will also hook in.

When it's built, the Big Pipe will move up to 740 million litres of raw sewage each day to the Pickering treatment plant on Lake Ontario.

Robb is furious that work was allowed to proceed based on what he says were "superficial and fragmented" studies that examined small sections in isolation, instead of the big picture.

And if early problems are any indication of what's ahead, the environment is in big trouble, he predicts.

The region began construction of trunk sewer in Markham in 2000. About 4 kilometres have been built south of Highway 407 in Box Grove, along 9th Line to Major Mackenzie Dr. Eventually, the sewer will be extended to Whitchurch-Stouffville. Another 2.5 kilometres runs along 16th Ave., ending at Stone Mason Dr. That section is to be continued west some 7 kilometres to Woodbine Ave.

To build the first phase of the 16th Ave. section, a tunnel had to be burrowed as deep as 50 metres into the ground to make way for the 2.7-metre-diameter concrete pipe — big enough to drive a car through. Millions of litres of groundwater had to be pumped out and discharged into streams and storm sewers so tunnelling could be done safely.

Problems began surfacing early in 2002, when wells several kilometres from the site began to dry up. As work continued and millions more litres of water were sucked from aquifers — underground lakes and rivers — the area of impact spread.

Within months, rural Markham residents living north of Major Mackenzie Dr. began complaining about well levels dropping dramatically and dirty water. They couldn't drink it, cook with it or bathe in it. "They pulled the water out from under me," says Lorne Smith, who lives on a farm on McCowan Rd. His well went dry.

Smith figures more than 15 billion litres of water have been drained since construction began. At least twice that amount will be sucked out before the 16th Ave. project reaches Woodbine, a project that will take three years to finish.

Work on that phase is on hold, but water continues to gush from the ground to protect the integrity of the first section of the tunnel.

"We're talking about an astronomical amount of water," Smith cautions. "It's insane to take so much water out of the ground without knowing what it's doing to the environment."

The region has installed temporary holding tanks at homes and farms with dry wells. For months, residents had to rely on water delivered by trucks. Many said it smelled and was undrinkable.

In May, a new well was drilled on Smith's property. Today, there's only about a metre of water left in it. Another will have to be drilled.

The situation is particularly galling to Smith and other rural residents because the sewer will be of no benefit to them.

But others see the system as a necessity and want the bickering to end.

"I think we have to have it," says King City businessman Jim Strachan, president of J.D. Strachan Construction Ltd. "It's obvious from all the consultants' reports, court decisions, environmental studies and the region that the pipe is the only solution."

Adds Mayor Black: "The Oak Ridges Moraine is being polluted by failing septic tanks. It is systemic and widespread. You can go and smell it throughout town if you want to.

"It's so widespread throughout the community, it needed an overall community system, not just septic tanks."

When water complaints began flooding in, Markham Mayor Don Cousens and council demanded the province withhold the region's permit to siphon more water from the ground until residents' problems were sorted out. Without the water-taking permit, construction could not continue on the pipe to Woodbine Ave.

"The region really dropped the ball when it failed to deal quickly with water problems facing our residents," the mayor says. "We showed the region the error of its ways."

But Cousens also doesn't believe a full federal environmental assessment is needed. And he stresses the sewer must be built because it's a vital part of the region's infrastructure.

Markham's demands were heard. York was ordered to prepare mitigation plans to satisfy regulatory agencies, including the provincial environment ministry, the federal Department of Fisheries and Oceans and the Toronto Region Conservation Authority, that construction of the Markham sewer wouldn't harm watercourses or fish habitats.

The region and its consultants have been working feverishly to come up with those plans.

Brian Denney, chief administrative officer for the conservation authority, says a water-taking permit hasn't been issued yet, "because we simply don't have a clear enough understanding of the implications of de-watering."

The region, says Denney, is using a new tool that wasn't available when the sewer project first began new tool — a high-tech computer mapping system that simulates what's under the ground.

One proposal being considered is piping some groundwater from 16th Ave. north, to replenish streams dried by dewatering. Another would see the cold groundwater heated before it is released into streams to protect delicate aquatic ecosystems, says Cousens.

At 10C, groundwater is colder than surface water in summer and warmer than winter, explains Lewis Yeager, manager of Rouge Park. Dumping water from aquifers directly into tributaries could harm fish that are highly sensitive to changes in habitat, he says.

Neither has ever been tried in the field, so there's no way of knowing whether the ideas will work or what the impact would be.

To Smith, it's all a bad joke.

"Can you imagine heaters working all summer so the water will be warm?" he says with a laugh.

Robb says the rural water problems are persisting because the region's studies didn't take into account the complex "Swiss cheese" of aquifers in the ground. When water is drained from a lower aquifer, it sets off a chain reaction in the underground network.

A comprehensive environmental assessment would show that, he says.

It also would find that water being pulled, at breakneck speed, from deep in the ground is saturated with high concentrations of minerals such as iron and cadmium, he says. These minerals pollute streams in discharge areas like Stone Mason Dr., where groundwater is being discharged into Robinson Creek, which flows into the Rouge

The mineral-laden water changes the chemistry of streams and tributaries and fish habitat.

In nature, Robb explains, minerals are filtered out over the course of hundreds of years as groundwater slowly percolateing to the surface.

Rocks nears the 16th Ave. discharge area are rust-coloured from the iron in the water. Some are coated with brown, fuzzy scum from an accumulation of minerals while gobs of goop cling to others.

"The water looks crystal clear, but it isn't," notes Robb. "The chemistry of water in the stream is changed and that could kill fish."

At greatest risk, he says, is the nationally threatened red-sided dace, a small fish found in local tributaries. Water spewing non-stop from several pipes on the 16th Ave. construction site is also eroding soil as it makes its way to Robinson Creek.

"At this stage, any reasonable person would have to agree that construction of the Big Pipe is doing serious damage to the environment and destroying fish habitats," Robb says.

He maintains the de-watering problems could have been avoided if the region had opted to build its sewer system below the water table. It would have cost more than the gravity-fed system — pumping stations and treatment plants would be needed along the route — but it would have been an environmentally friendly system.

Yeager agrees the Big Pipe should have come under the scrutiny of a full environmental assessment. But even if the project is stopped, development doesn't have to, he says.

The region could implement an "aggressive" conservation plan and disconnect storm sewers currently linked to the York Durham Sewer System, freeing up space and extending its capacity by several years, he says.