Me, I can’t help it. Fly fishing is like the stock market and every channel has some nicely powdered fellow telling you what to buy. Most ignore the larger picture in favor of the populist message; get in now, you’re missing it.

Fishing has the same urgency for me, as I’m forced to eat a great deal of bad news and mold it into glib commentary. Which is why I’m fascinated by stream science (in all its many forms) and insist on posting these tasty little nuggets – despite your collective yawn.

It’s mostly about fresh potable water, something that our piddly little sport requires in great abundance and in the pristine variant. With the increasing density of humans and the decline in freshwater quality, most of the streams we hold dear – will be squarely in the crosshairs of plenty of important people, numerous multinational corporations, and all of them will have bigger war chests and more political clout than every conservation group added together.

… but that battle is still decades distant.

Right now, it’s about 20% of the dragonflies and damselflies disappearing in the Mediterranean, due to the scarcity of fresh water.

Dragonflies are generally known for being good indicators of water quality. Major threats for 67 percent of these Mediterranean species are habitat degradation and pollution. The Spotted Darter (Sympetrum depressiusculum), which used to be common in the Mediterranean, is now listed as Vulnerable and is declining due to the intensification of agricultural practices in rice fields.

Pollution and rice fields, sounds mighty familiar.

I tromp through the same chemical brew here in California, fishing for panting trash fish covered in Copepods, knowing that some kindred spirit in Italy is cursing his politicians as violently as I am. His damselflies will go the way of my salmon, one day they’re here and the next … the supermarket freezer has pallid stacks of frozen “color added” …

Then it’ll just be us guys spinning yarns about what used to be in that toxic rivulet the neighbor kid emptied his motor oil into.

… but Science ain’t all bad. I’m forced to wallow through an aggregation of dead, diseased, and dying – to find the occasional scientific nugget to cheer us all.

It may be safe to put them big feet back in the creek, as the sand and sediment stirred by your sliding through the fast water allows the creek to hold its shape.

Sand and siltation has always carried the evil label, as it’s known to cover spawning gravel and terraform a cobble bottom to its liking. UC Berkeley researchers suggest it also plays an important role in cutting off meanders allowing rivers to avoid fragmenting into many smaller rivulets.

The significance of vegetation for slowing erosion and reinforcing banks has been known for a long time, but this is the first time it has been scientifically demonstrated as a critical component in meandering. Sand is an ingredient generally avoided in stream restoration as it is known to disrupt salmon spawning. However, Braudrick and his colleagues have shown that it is indispensable for helping to build point bars and to block off cut-off channels and chutes–tributaries that might start and detract from the flow and health of the stream.

Animal trails and depressions in the landscape can be scoured deeper with Winter’s flows, providing the opportunity for channel formation which splits the river and diminishes flows along both branches. A combination of bank side growth and instream sand forms a “self sealing” repair kit preventing channelization of the riverbed.

Science. I got your reality show right here, babe.

Tags: channelization, meander, UC Berkeley, siltation, sand, bankside vegetation, dragonflies, damselflies, rice, tomatoes, pollution