there is a new to me datum in that trees along residential streets are experiencing less water stress than trees in parks, due to city water leakage that was demonstrated by doing core samples on the trees to show how lead isotopes differed in the two populations of trees.
it highlights a growing concern with water in general and how carefull water monitering and management is becoming, and how what was primarily interesting to civil engineering types, has a wider audience
Heh. Yesterday, we had a plumber over who told us we have to rebore our sewage pipes because roots got in. It is an old house with cast iron pipes and they still got in.
> While the park trees contained lead isotopes normally associated with air pollution, the street trees had isotopes found in lead water pipes, which were made with metal from geologically old deposits in nearby mines.
I don't understand this part. We didn't use different sources of lead to make leaded gas and lead pipes, no?
I wonder how much human health is impacted by these leaky pipes.
I would like to see a city where pipes are guaranteed leak free, for example by making them double walled with high pressure air in the outer layer, and then seeing if disease levels in the city are lower.
> Maple trees need to consume around 50 litres of water per day. Since street trees can’t get much of this from rainwater, which falls on concrete and drains into the city’s sewers, Poirier says the most likely explanation is that it is coming from Montreal’s leaky pipes, which lose 500 million litres of water per day.
The city where I live estimates that we lose somewhere between 25% and 30% of drinkable water to leaky infrastructure.
We've had something close to a drought this summer -- unseasonally long periods without rain. You can see the young trees on the streets and trees in the middle of large parks suffer from it - wilted leaves and leaves dropping earlier than usual. BUT, large old trees seem to be thriving - full canopies, lush, firm leaves.
I've been suspecting the big street trees do so well because they benefit from the dilapidated state of our water delivery infra. It's nice to read of a study that confirms my amateur observations and musings.
I wonder how many of the pipes are made of wood. I forget the source, but I heard a decent number of pipes in Montreal are very old and made of wood (which is better than the proliferation of lead pipes that are still being removed)
Not only trees in cities do that. A lot of clogged home sewers are caused by trees that wanted more to drink. Once the sewer line is fully blocked, they've arrived in paradise. Now there is a constant supply in the permanently filled sewer line.
I use to live on a property in a development. On my property were a pair of big willows. The trees were large and healthy, well over 50' tall. That was strange, because the region is high desert with little water, and I made no effort to irrigate them.
One morning in spring, after I'd been living there about 15 years, the neighborhood streets flooded. There were geysers of water shooting up from manholes. Turns out, the willows had been planted over an irrigation ditch[1]. The willows had driven their tap roots into the pipeline and plugged it about 10' underground. When the water authority opened gates miles upstream, the water pressure blew water up the manholes into the streets and a few yards.
Farmers are very motivated to get their water. They, and the ditch company, rapidly cleared the plug and removed the trees.
Before this happened I had no idea the irrigation system ran through the property. I knew about an easement, but I thought it was for sewage, because the developer used an iron manhole cover from the local municipal waste management operation when they covered the irrigation ditch: it literally had "Sewer" cast into the iron.
[1] Formerly an actual ditch, later made into a pipeline and covered over, but still technically a "ditch" for purposes of water management.
One of the houses across the street from me had its driveway dug up, all the way from the street to inside the garage, for what I first thought was for putting a bathroom or something in the downstairs level. When I walked past the old pipes they took out they were full of roots.
Trees have led the humans to channel water and irrigate them so they survive even in dry and isolated soil, and provide shade for urban areas in exchange.
Not really mentioned, but I suspect that at least part of the time, the leaky pipes are caused by the trees. I used to own a house in southern California with a sprinkler system and a couple Chinese elms. Trying to track down why some sprinkler heads weren’t sprinkling, I discovered that the trees had sent roots into some of the (PVC) piping, going as far as six feet of the pipe. I ended up digging up and replacing a lot of piping on that project, although I wouldn’t be surprised if the Chinese elms (which are nasty nasty trees that I will hate until I die) didn’t pull the same stunt on subsequent owners of the house.
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[ 3.1 ms ] story [ 55.3 ms ] threadI don't understand this part. We didn't use different sources of lead to make leaded gas and lead pipes, no?
I would like to see a city where pipes are guaranteed leak free, for example by making them double walled with high pressure air in the outer layer, and then seeing if disease levels in the city are lower.
I feel like this is burying the lede.
What can be done to reduce leakage?
We've had something close to a drought this summer -- unseasonally long periods without rain. You can see the young trees on the streets and trees in the middle of large parks suffer from it - wilted leaves and leaves dropping earlier than usual. BUT, large old trees seem to be thriving - full canopies, lush, firm leaves.
I've been suspecting the big street trees do so well because they benefit from the dilapidated state of our water delivery infra. It's nice to read of a study that confirms my amateur observations and musings.
One morning in spring, after I'd been living there about 15 years, the neighborhood streets flooded. There were geysers of water shooting up from manholes. Turns out, the willows had been planted over an irrigation ditch[1]. The willows had driven their tap roots into the pipeline and plugged it about 10' underground. When the water authority opened gates miles upstream, the water pressure blew water up the manholes into the streets and a few yards.
Farmers are very motivated to get their water. They, and the ditch company, rapidly cleared the plug and removed the trees.
Before this happened I had no idea the irrigation system ran through the property. I knew about an easement, but I thought it was for sewage, because the developer used an iron manhole cover from the local municipal waste management operation when they covered the irrigation ditch: it literally had "Sewer" cast into the iron.
[1] Formerly an actual ditch, later made into a pipeline and covered over, but still technically a "ditch" for purposes of water management.
Trees have led the humans to channel water and irrigate them so they survive even in dry and isolated soil, and provide shade for urban areas in exchange.