In 2013 I developed and published something called the flow-channel fitness model (FCF; Phillips, 2013; attached). Fitness refers to the fit between channel size or conveyance capacity—yes, it’s a problematic concept, but a venerable one in hydrology and geomorphology. Underfit channels are “too large” for the range of flows they typically convey. They often occur where large channels and valleys were formed during previously wetter climates, or by megafloods or glaciers, with those big ‘ol channels now occupied by smaller streams that rarely overflow their banks and can’t do much to reshape the channel. Overfit channels are “too small.” They frequently can’t hold all the discharge that comes their way and flood frequently. Fit channels, at least as conventionally conceived for alluvial channels in humid climates, have a reasonably good match. They flood (on average and according to the conventional wisdom) every year or two but otherwise hold their water.

Everything is connected to everything else has been called the First Law—of ecology, of geography, and of environmental science. But why do environmental systems become so highly connected, and generally remain that way? Not quite satisfied to just say that's the way it is, and following Aristotle, who said that nature does nothing without purpose, I've been working on an answer to the why The First Law holds. I've produced a manuscript on this called Why Everything is Connected to Everything Else, abstract below, and attached to this post. I'm calling this a preprint, in hopes that it may eventually be published somewhere. But experience suggests that my odds of getting into a scientific journal are not great. Comments, criticisms, and corrections are welcome. 

Abstract

Some recent kayak trips on the North River near Beaufort, NC (which, naturally enough, is north of North River, SC, but strangely enough well south of the other North River, NC, and even more strangely, south of the South River in the same county) revived some nagging questions about the source of sediment to coastal marshes. 

Freshly deposited mud on the North River marshes.

Most of my work in this context has dealt with larger rivers on the Atlantic and Gulf Coastal Plains (drainage basins >15,000 km²) addressing (among many other things) how much fluvial sediment is delivered to estuaries and coastal wetlands, and where within those drainage basins it comes from? Some updates and reminiscences were covered in this post. Essentially, my work (and many others) has found that in many river systems much of the sometimes-considerable sediment loads from the upper watersheds never reaches the coastal zone, being stored as alluvium in lower river reaches. Much of what does reach the coast derives from coastal plain sources near the coast, not from upriver.