I missed my regular Saturday posting time, sorry Andy. We had a jam packed weekend, evidence of which will turn up in subsequent posts. But for now, here's a piece I wrote a prior to the weekend.
A small stream bisects my farm. The entire watershed that feeds it is only about 500 acres, half of which lies on one neighbor's farm up the hill to the west. In the five or so years I've lived here there have been two "hundred year" floods. I blogged inarticulately about the first of the floods on the old blogspot here and here. The second washout occurred during May of last year when greater than five inches of rain fell in less than four hours, and the soil was fully saturated from the snow melting off a few weeks prior.
Both events distressed me because they carried away alarming amounts of soil as the stream cut into its banks and dug its channel deeper. I believe ag practices from decades ago contributed to the severity of both erosion episodes. The evidence of old fences from this farm's dairying heyday indicate that the stream spent many years as a "pasture" and water source for cows. Set-stocking a length of stream with a high number of cows allows them to graze the riparian vegetation down short - short grass means short roots and little ability to stabilize the banks. Cow hooves cut into the banks and push dirt down where the water can get ahold of it. The vulnerable streambanks then begin to erode. I also know that previous owners dug at the streambed with excavators to keep it in its channel, deepening but not widening its course. A straight downhill shot with no meanders and weakened bankside vegetation may not be a worst case scenario, but it certainly isn't a good one. Water disipates energy and deposits silt and gravel in meanders. Without them a flood just gains greater and greater momentum. When it finally begins to undercut a streambank it can carry off tremendous volumes of dirt.
The flood in 2011 was bad and the one in 2014 was worse. After the 2011 losses a fully-funded grant from the Federal Government NRCS/SWCD paid for a crew of guys to spend three days weedwhacking and planting trees along nearly 2000 ft of stream in the spring of 2012.
Their regulations required that they plant 8 feet back from the banks and preferably in three rows each 8 feet from the next, though I only allowed one or two rows. At the time I did not understand the rationale for any setback, and still do not understand it. At the time I felt the use of money from the Federal Government was justifiable since using it on my farm potentially benefited so many people downstream in the form of erosion control in the upper Chesapeake watershed (where my farm is located). I thought sacrificing a bit of my land (the setbacks) to stabilize the stream was an OK trade. After the planting there was almost no rain for three weeks. 90% of the new trees died. All that time and manpower ended up being for naught.
A month or so after the 2014 flood I had an NRCS employee come out to look at my situation. He proposed applying for a number of different grants, both state and federal. It sounded like he'd probably be able to work up a 90/10 cost share where the government, i.e. you, would pay for streambank stabilization. I'd have to sacrifice a little more land, pay a bunch of money since 10% of $50,000-100,000 is still a substantial amount, and have a lot of earth moving equipment rip up my stream and help it meander "better".
Rather than resort to another round of grant applications, depend on beauracracy, and succumb to regulations poorly suited to my farm I decided to take matters into my own hands. For one thing I couldn't get past the inane rule to plant trees set-back from the banks. Clearly the stream is deep enough and powerful enough to under cut them and pull even moderate size trees into its gaping maw. Maybe in other places with different soils that kind of setback is advisable, but I'm pretty sure in my situation it is not. Nor did I see the sense in spending a lot of my own money and tons of your money on earth movers to create meanders. My assessment of the situation was (and still is) that the streambanks that best withstood the abuse of a raging torrent were lined with scrubby willows growing at the base of the bank, essentially in the stream at the water's edge. Why not plant many more trees there? As for the meanders, when the water gnaws at its banks it sets up a zig zag pattern of taking dirt from the north side of the stream and then a few tens of yards farther it takes from the south bank. To my eye the stream is trying to dig some energy dissipating curves for itself, as much as any natural feature of the landscape can be ascribed intention to "try" to do something. If the stream will dig its own meanders in the coming years why spend tens of thousands of dollars and burn untold gallons of diesel fuel? If both the quick diesel-powered high-dollar course and the patient, nature driven no-dollar way require I give up some land, why spend all that money for the same ultimate outcome?
Still, I don't like sending my dirt off the farm by the cubic yard when it floods. The solution I struck upon was expedite the willow colonization of my waterway. Willows already volunteer along many feet of my stream, and as I mentioned previously, every where they set themselves fared quite well during the floods. One of the many commendable features of the willow tree is its incredible ability to push roots from cuttings of smaller branches. Take any willow and snip a small or medium branch off. Stick said twig into damp soil and it will grow roots and establish itself as a tree or shrub according to the parent plant.
In April I took numerous cuttings from a few wild willows whose form I liked and plugged them into thousands of feet of streambank, especially along the dirt faced cuts where the banks were most likely to erode. The results so far look promising. I estimate 80+% survival of my plantings and they're all well rooted at this point.
All in all I invested about 4 hours of labor cutting, carrying, and plugging willows this spring. The planting stock was free since I took cuttings from trees growing on my land. Compare that with the 160 man hours, and 1000+ dollars worth of saplings and planting materials the NRCS poured down the drain on our farm in 2012. Or compare it with the potential $100,000 they'd put into it if I sprang of the big program. Now if I could just get somebody to pay me $25,000/hr to plug willows into a streambank I'd be on to something.
There are two willows in this photo. One leaning over pointing at me and Nyssa. The other is stuffed into the bank on the upper left of the image. It reaches from the top of the bank down to the water so it doesn't dry out during low rain periods.
-Edmund