Mud Slips & River Whims – Post Flood Ecology

by on October 19th, 2008
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cliffpatterns2sm.jpgMud Slips & River Whims – Post Flood Ecology

By Jesse Wolf Hardin

(www.animacenter.org)

The canyon and most of the Southwest was hit by a short but particularly violent storm last weekend (October 11th and 12th, 2008).   The ground was lashed by a tumult of rain and sleet, moisture spun off by a tropical storm that had hit the gulf coast of the United States earlier.  Usually the ground soaks up a substantial amount of rainfall, before it becomes so soaked that it can take more and the water races down well worn gullies to the so far insatiable river.  It is rare in my experience for the ground to be essentially dry at the onset of a storm, yet have so many inches of rain fall that it immediately begins running off across the whole of every surface.  One result in what we call sheet erosion, stripping away an inordinate amount of soil.  Not only the sandy composite, which is always the first to go, but also banks of clay that are pulled down the hill and deposited in thick layers at the canyon bottom.  The river both swelled and then shrunk again quickly, darkening not to the more typical reddish brown but to the slick gray sheen of a potter’s clay slip.

Whenever the river overflows its banks, things change.  Some are partly predictable, like the way fallen trees or rock outcroppings result in curving meanders, or that a flash event carves steep vertical cuts in the banks in the places where we depend on our jeep to cross.  Just as often there are surprises, such as one flood scooping out a 15′ deep hole that we do high dives into from 20′ up the cliffs, then another flood 3 months later turning the same bend into a sandy beach ready for a family picnic.  The flood last Spring deposited so much sand that we were surprised the plantlife could grow back so vigorously this Summer, but this most recent surge left us with large amounts of the ultra slick clay instead – the same material that the ancient Mogollon peoples used to make the bowl whose pieces we still find scattered on the ground.  And not even the mud has been consistent.  The area by the first crossing where we park our road car is usually impassable without four wheel drive after a good storm, but within two days was uncharacteristically dry.  The 7th crossing coming in still features a 2′ deep mud bog on one side after a full week of sunshine.  Oddly enough though, the crossing itself changed from loose sand that was hard to drive through, to being rocky and firm, and the far bank that was a steep wall of fine loose sand is now a gentle and easy slope.

Van, who own ands manages half of our 80 acre inholding, has made a study of stream and river morphology and dynamics, and a business of their restoration and repair.  Two or more times a year he arrganges for groups of volunteers from the Sky Island Alliance to gather here and do work on the Sanctuary.  He will be pleased to know that the berms they built this Summer on the trail in did a great job of diverting runnoff into forested areas that could capture the soil, and their rock berms also held more water long enough for it to penetrate into the ground where it is needed by the new growth’s thirsty roots.  A thank you goes out to everyone who has ever helped with the restoration work here, from us and every life form better able to thrive because of these efforts.

These periodic high water events point to the value of our understanding and actions down here.  They also remind us of the folly of imagining we can ever fully comprehend and predict a river’s course… remind us of the ultimately fortunate impossibility of ever controlling the wild nature that determines its roar and trickle, ebb and flow.

(To volunteer here, write us.  Please consider offering your time to Sky Island as well, by going to: http://www.skyislandalliance.org/volunteer.htm    ….and feel free to send this article to others)


Categories: Anima's History, Jesse Wolf Hardin – Essays & Tales

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