I saw a Canalworld Forum discussion about new regulations to keep dogs on leads along the towpath along the Regent's Canal, with threats of fines for non-compliance. You can see plenty of the notices on the Lea navigation, alongside the Hackney Marshes. The forum discussion seems to focus on the nuisance of dogs fouling the path (not sure how pooing on the end of a lead would be any different!), before drifting off into the nuisance caused by speeding cyclists.
I was wondering about the timing of these new restrictions. As many know, Leyton Marsh has been the subject of much protest recently, over the development of a basketball centre for the Olympics. The open land alongside the canal, where people and their dogs wander freely every day, has been dug up and built on, with heavy security keeping the community out. It's not the only shiny metal and concrete structure to have sprung up along that stretch of common land, close to the canal I see. Anyway, it seems that three dogs that walk that area had toxic poisoning within a few days of each other. Of course it may be completeley unrelated but about 3 weeks later, the notices restricting dogs went up all along that stretch of the canal.
I'm guessing that the marshes hold still water almost permanently and that disturbing the soil might release some of London's pollutants into surface, drinkable water.
Here's what a Guardian article said at the start of the year:
"The Environment Agency, which has worked with the Olympic Delivery
Authority (ODA), the London Development Agency and other partners on the
site said it had helped the ODA decontaminate 2m tonnes of soil so it
could be reused."
Another report says:
"The main site for the 2012 bid, the Lower Lea Valley, is the largest
area of derelict and contaminated land in the capital"
I'm just a bit sceptic about how efficiently you can decontaminate large areas of land without releasing chemicals and other pollutants into groundwater and air. We don't often see for ourselves the effect on wildlife, but I guess the health of our own dear dogs is very much noticed.
But hey, I'm just a conspiracy-theorist.