Trees on city streets cope with drought by drinking from leaky pipes

Why should anything be done to reduce leakage? They take water out of the St Lawrence and, as much isn't diverted by trees, it goes back in (cleaner then when it came out.)

Hopefully the lede, lead would be an even bigger concern.

That double wall thing is a red herring. The water system already protects against intrusion because the water itself exerts pressure on the pipes. Thus leaks are typically of the water getting out and not contamination of the water (most of the time, anyway.)

Contamination rarely happens outside of the source of supply, and not somewhere along the pipeline.

Water pipes are under pressure. So outside water and pollutants do not infiltrate into leaky pipes. Unless you have a water shutoff. But those situations are minimal.

Alameda county does something similar for health reasons. All home sales require pressure testing the sewer lateral. With replacement required if it fails before the deed can transfer or a loan is funded.

For what it's worth, utilities do care quite a bit about leaks (it's service they are providing which they can't bill for!) and use various testing apparatus to locate leaky parts of underground systems for repair and replacement.

Considering the difficulty and cost of repairing underground anything, most of which will be there for many many decades, it's never going to be perfect, but there's a lot of resources that do go into improving this.

We already have this data in a way, from cities where there is no running water and people rely on bottled water for drinking and washing.

Those leaks are 99.9% one way.

We had a lemon tree that did this. The irrigation line connector was probably not 100% sealed and the roots grew to it slowly broke it. It enabled the lemon tree to gets lots of water and grow. Meanwhile the trees further down the irrigation line suffered.

Some genius planted a curly willow right in the middle of my house’s septic drain field. That tree cost me $20,000.

Tetraethyllead production was very centralized by Ethyl corp/DuPont and required a higher purity lead ore so their isotope ratios are very well known based on the deposits that they mined. More locally sourced lead used for construction will have different isotope ratios.

When you need a lot of lead (enough to build plumbing for a neighborhood), you probably want to source it locally. When "1 part TEL to 1300 parts gasoline by weight is sufficient to suppress detonation",[1] you can source the lead from just about anywhere and ship it with the fuel.

1: https://en.m.wikipedia.org/wiki/Tetraethyllead

We didn't put elemental lead in gasoline, it was a very different molecule with a single lead atom. Given how dense lead is, you want to source it from as physically close as you can. A foundry making pipes in a city with a lead mine nearby will obviously use the local lead.

For gasoline, all production had to be centralized in a few refineries. The lead would have been shipped in, and would have been largely the same quality and age, likely coming from the same mine, or geographically close mines. Plus the absolute quantity of lead added to gasoline is relatively small. In the 60 years the US used TEL, we processed about 8 million tons of lead. Averaged out, it's 133 thousand tons a year. It would only take a few mines to provide that much. Probably not more than five or ten, but I can't immediately find good data on this.

One would expect that the lead used in gasoline is pretty homogeneous across time, and that intensive lead use (as in casting into solid metal object like pipes) would use the nearest available source, and use that source for as long as possible.

lead from pipes was mined localy, but the lead in parks soil is from airborn pollution and so the isotope signature will be quite different

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.

Decades? Try millennia.

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

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