permaculture

[Rick Valley <bamboogrove@cmug.com>]

> From: "Eugene F. Monaco" <efmonaco@comcast.net>

> I've always heard (haven't tried) that bamboo works well on the surface of
> small dams because the roots don't go down that deep: that they form a mesh
> reinforcing that holds things in place.  Now we're hearing that they can go
> 12 to 15' deep.  Does anybody envision a time bomb here?  A dam break can be
> a nasty thing.

Again, to keep in mind that the fibrous roots of grasses (monocots) are not
the same as the big roots of dicots, which open large channels. What earthen
dam does not have grass growing on it? One other major reason bamboos help
earthen structures and drainfields is that they pull alot of water out of
the soil. In fact, bamboos are planted over no-outlet septic systems for big
cats in zoos. (nasty parasites- don't want it out in the world)

Running bamboos have shallow RHIZOMES, underground stems, which do indeed
act as cables across earth. During earthquakes in the Orient, fissures do
not open in bamboo groves- they go around. Likewise, bamboo can protect
river banks. (although, clumps can be torn loose, lodge downstream, and grow
in the new location) Oneinteraction to look oet for would be bamboo
sheltering burrowing rodents which could tunnel and let water out. Ya gotta
mow the grass or thin the bamboo, either way.
As far a trees on a dam, one Govt. civil engineer told be that during floods
in N. California, the dikes which were "poorly maintained" (ie had trees
growing on them) were the ones that did not break. Personally, if I had
trees on a dam, I'd coppice them regularly so I didn't get blow down ripping
up big chunks.

Eugene; The reason your bamboo went into the berm was because it was
disturbed soil- easier to grow into. So the bamboo grows even deeper, then
puts up wonderfully sharp-tipped shoots through the barrier. Oops!
The plastic barrier that is being used for bamboo confinement these days is
"high density" poly, 30 to 50 mil. It's as tough as blow-molded nursery
pots, semi-rigid.

-Rick