Hoo-kay, I have got the following possibilities from readers concerning my driveway bump.
- Tree root (many, many).
- A rock.
- Mushroom. This reader is apparently serious — he signs off as “veteran of the mushroom/asphalt war.” Another reader confirms: “The cure was to drive a large nail or spike into the middle and pour fungicide down the hole. When the ‘shroom dies and rots away just step on the bump and is should go down to its original position.”
- Sucker. (The bulge, not me:) “Hello Sir. I am a plant pathologist. I believe what you are seeing is not a root from a nearby tree but a sucker from a near surface root. My guess it is that of a locust tree of the Robinia genus. They are quite prone to this. It is a survival mechanism of some plants to do this. Often the main trunk of a tree will succumb to a crown rot or other disease or mechanical damage that does not spread through the entire root mass. The plant “senses” that its photosynthetic nutrient source has changed and can respond by sprouting what amounts to a new trunk. A really fast way of getting a locust forest is to cut down an established specimen and stand back. The roots will produce a million little trees in no time at all. They have been know to push the liner of an above ground pool, so a macadam driveway is no feat.”
- Well, well. This from an actual engineer/surveyor: “Looking at the picture it could be an old well. In areas of regional subsidence old wells are deeper and will not subside at the same rate as the surrounding land does. It’s called differential settlement. Sometimes you’ll see this exhibited by manholes in the street that seem to pop up. It’s actually the ground around them that is going down.
If this is the case there is a way to fix it. That is to dig the area up (in this case 4′ deep might do it, but the deeper the better) and saw off the pipe. Then place a reinforced concrete slab (with as large a footprint as is practicable) over the cut pipe, before backfilling. The slab will help distribute the point load of the pipe as it tries, in future, to ‘push its way up again’ (actually, as the surrounding grade continues to differentially settle).”
- Dandelions. “Had the same problem, up thru hard pack soil 4 inches of gravel and up thru asphalt. Propane torch to soften and hammer to pound it back down. The only way I know to kill dandelions would be find a profitable use for them and try to start a dandelion farm.”
- “Mr. Derbyshire: Not sure what the problem is with your driveway, but dynamite is the solution. Can use it for fishing too.”
- Alien: “Just to be sure, I recommend blasting away at it with a shotgun a few times. Before you do so, be sure to invite over any male neighbors so they can enjoy the show.” [Me] Darn, not yet bought shotgun, though pretty much set my heart on a Mossberg 500 “Persuader.” Just love that name: Persuader. Do space aliens yield to persuasion, though?
- Burst water pipe: “John: Unfortunately, that bump in your driveway could be evidence of a broken high-pressure water pipe underneath. If so, it will only get worse before you repair it. If you puncture the bump with a sharp pole, and water starts spraying out, then you’ll have your confirmation.” [Me] Can I try the shotgun thing first?
- Volcano. “You should talk with Jonah about lancing it immediately — preferably with some sort of airborne laser.”
- Jimmy Hoffa’s head.
- Reproduction: “Mr. Derbyshire: Obviously, your driveway is pregnant. Very shortly, you should find a small, new sidewalk next to it.”
- C.H.U.D. (Yes, I know, that’s a null Wikipedia link. I’m assuming this is some kind of postmodernist humor.)
- No suggestion or solution, just cultural references. I guess this and the previous are from the Humanities cohort of NRO readers, the practical suggestions coming from the Sciences. Most popular cultural tags: Caddyshack, and THE WORST POP SONG IN THE ENTIRE HISTORY OF THE COSMOS.
Many thanks to all who contributed, especially the experts. I’m thinking shotgun, shall send out invitations to neighbors: “Shotgun party, Derb driveway, date/time TBA, bring own lawnchair, cooler, snacks, teenage son needing instruction in manly pastimes, etc.” (Dynamite wd be more fun, but hard to acquire here in Hilarystan.)