iBrowseAtStarbucks

Also a CivE, but not on this project, but can answer the general ones.

US Army Corps of Engineers (USACE) is a branch of the US army that works on public works projects. They get called in anytime something gets done on a military base, superfund site (polluted site), dams, reservoirs, the list goes on. For all intents and purposes, they're a big civil engineering firm that is owned by the government.

Soil studies are mostly for bearing capacity. They look to make sure the earth can support the structure they're building, not necessarily if the earth will be changed, if that makes sense. Regardless of what happens to the sands at the base, the actual footing will be designed to hold, making the fence as a whole, still a fence.

Design life for something like this will probably be 20 years. Realistically you'll see this standing for more like 50 with some spot repairs and maintenance. Gotta keep in mind this is the middle of a desert - not exactly good for longevity. I would also be interested to know the exact design life of this though!

Wow that’s wild. My immediate thought was of how airplanes used to have smoking on board and how she was probably around for that. Didn’t realize that practice didn’t officially end until 2000.

I'm a storm water engineer.

Permeable pavements are good, but there's always more to do. That whole family of improvements is called LID methods, low impact developments. To give you an example of some other stuff, segmenting pavements (lateral cut every so often in your pavement that looks suspiciously like an expansion joint), removing curbs and gutters, rooftop gardens, properly developed swales, the options are endless.

Permeable pavements are typically one of the more expensive changes you can make. If you're interested in how they're made, it's a regular asphalt mix that's compacted to around 10% air voids instead of the regular 3-7%. They have a much shorter usable life and tend to lose their water conveyance capabilities over time.

To give some numbers for effectiveness, regular pavement we usually say has around 99% runoff, meaning 99% of water hits pavement, then goes somewhere. The 1% remaining is called the initial abstraction. It's what we effectively lose to nature. Permeable pavements are around 85-90%, markedly better. Trees and grasses are anywhere from 10-30% though.

If your goal is to do more, that's where you start. Busting up concrete and asphalt is our best option to help, no way around it.

Finding an alternative to the blast furnace process will pay higher dividends. Concrete can be recycled through RAPs (reclaimed asphalt pavements) and other such recycling. Plastics degrade too much over time to be used and reused.

Concrete has a specific range of setting temperature inherently. Too hot or too cold and it will never set right.

Fun fact: this became a huge problem in constructing the Hoover dam. Concrete gives off a lot of heat when it hardens and it made other nearby bits of concrete slower to cure.