Category Archives: bankfull

Like a River… TIP #1

River TIP #1: Protect your floodplain.

Hello, Beloved River Folk.

Today begins a series of the five Top Important Points (TIPs) for enhancing the rivers you love AND living like a gorgeous, healthy, wild river yourself.

When you follow TIP#1, you almost don’t need any other tips because your river has a deep resilience. Then it doesn’t matter what happens: your stream handles it. You thrive.

In a nutshell

Every natural river has a place to spill when things get big and fast and crazy. A floodplain has three characteristics:

~ open,Stream Type B... somewhere in my great-grandparents' homeland of Norwegia

~ level, and

~ connected to the river.

What’s that look like for a human? Where can your excess energy spread out and calm down? Is it walking outside, lying next to your fireplace, laughing with a friend, letting your pet snuggle on top of you, stitching things, building things?

I would NOT say a floodplain is “next to the river.” The floodplain is not a separate entity. The floodplain is as much a part of the river as the bed and banks. Remembering this may be the one easiest way to revolutionize river wellbeing.

That’s the core of Tip #1. If you want to delve into the why’s and wherefores, feel free to read on. Either way, I’d love to hear your comments and stories about floodplains both riverine and personal.

Yours in peace, love, and wild rivers,

Betsy

 

Why

Your river channel alone CANNOT be big enough to accommodate your floods.

~ Picture such an impractically huge channel: It would take up a whole valley.

And that over-sized river wouldn’t work well in regular or low flows. You’d have a thin sheet of water without cool-dark pools, oxygen-providing riffles, or tree-lined banks.

~ When a floodplain DOES become compromised — when flood flows get squeezed into the area between the river’s banks — that huge amount of water has to move quickly and that gives the water excess power. It has no choice but to cut down into the river’s foundation.

–> This is the most sure-fire way to begin a “head-cut” and unravel a river. <–

A floodplain saves the river from erosion by acting as a safety valve. It allows floodwater to leave the channel, get wide and shallow, and therefore lose velocity and strength. Then the water’s too weak to cut into the stream bed or banks.

Here’s the cool thing: it’s a two-way win because the floodwater also helps the floodplain. The slowed water doesn’t have the strength to carry the load of fine dirt, nutrients, and seeds that it gathered upstream, so It drops that material all over the floodplain. The enriched soil grows lush plants, and the plants in turn support lots of different life forms.

Actually the benefits extend even further! Upstream animals visit the stream before heading back home to reproduce, hunt, and be hunted. In other words, the river feeds the entire ecosystem. Win-win-and-WIN.

Your safety valves — your pets, friends, family, home, neighborhood, best-beloved beach or mountain — also benefit from your presence when they are “helping” you. And the world at large benefits from the ripples that radiate from your relief and gladness. Never think you need to “spare” your floodplain.

Your floodplain welcomes your floodwaters.

But here’s the issue I have noticed among us humans: In order to buy into the importance of a stream’s floodplain, we first have to accept the fundamental hydrologic fact that floods are fine.

Floods are natural. In a wild stream, some water leaves the banks and spills on to the floodplain about once every two years! Sometimes it’s a huge amount of water; sometimes it’s a small amount. I can’t stress it enough: flooding is normal and to be expected. It’s not a freak occurrence. It would be weird if flooding didn’t happen regularly.

This is as true of your life as it is your river. Floods are unavoidable. And that’s wonderful because…

Floods are healthy for the river, essential in allowing it to move rocks and dirt through the system.

And floods nourish life around the river and beyond.

Of course, each type of river has a different kind of floodplain:

Straight, fast step-pool-types have a tiny ledge-like floodplain, whereas slow-elaborately-meandering-types‘ floodplains take up huge valleys.

Natural Channel Hydrology differentiates eight stream-types. Want to know which kind of river you are? Click here to take the quick quiz!

Even though all floodplains are different, it’s not complicated to build, maintain, or re-build them.

How to

 All you have to do is let the river be the river.

1. Allow floods to happen

Don’t try to dam up big events. Event-full lives and river systems are the best (which is awesome since they also are unavoidable). Let the happenings, ideas, and emotion flow because that wide variety of power and nourishment automatically builds your channel and floodplain to be exactly the perfect shape for your climate, soil, and geography.

2.  Identify your “bankfull boundary”

In between the floods and the trickles there is a flow that forms your river’s banks. It’s not as easy to identify as you might think (particularly if a river has been messed with by humans). Click here to learn more, but meanwhile, think of this: your bankfull is where you find yourself sitting most comfortably on a late summer day to have a picnic. It’s the most peaceful place along your river.

3. Identify your floodplain and make sure it’s open, even, and accessible to the river

Once you know your bankfull level, look IMMEDIATELY next to it for a flat area. Then…

Keep it wild.

~ Do not allow anything un-natural in this entire area: no buildings and no man-made piles of extra dirt that stick up above bankfull elevation. Keep all such obstructions as far, far away as you can. This is easier said than done; such a lush area is attractive to outside development, and there is also a tendency to build berms to keep the floodwaters “under control.”  Just say no!

~ Trees and bushes are, of course, are welcome. In fact, their deep roots are important. Don’t be tempted to clear them and plant civilized grass.

As a human, you can and should have other living creatures as part of your personal floodplain. How to tell if someone is helping or hindering your flood relief?

: If a person, creature, or situation obstructs your flow — narrowing you or making you move more quickly — gives you the sense that the ground under or around you is eroding, or seems bothered by the sheer volume of your living, then they need to be moved well away from your daily life and your super-charged times as well.

:If a person, creature, or situation makes you feel more peaceful in the intense times — and your presence in those times seems to nourish them as well — then you have found your floodplain. Guard it.

~ As you evaluate, protect, and clear your floodplain, start close to the regular channel and move out from there. First and most especially, protect your bankfull edges. Keep development and livestock away from them or your boundaries will be erased. You won’t even be able to identify your floodplain. (Furthermore, without intact bankfull banks, your river’s dynamics can’t work at any flow level.)

Fences are fine because water can go right through most of them without constriction. In fact, nowadays, somewhat ironically, unless you live in a remote, huge landscape, good fences make for wild rivers.

So there you have it, my friends: may your floodplains be wild and your fences strong and wildlife-friendly. I hope I see you tomorrow for River TIP #2!

 

… with a very real boundary

Boundaries — they’re not just for other people

~ Bridgette Boudreau

Those seven words made me laugh so hard that they actually got me thinking about boundaries in a real way. (Proof that taking things lightly is miracle-inducing.) As in, where do we set them and how and… what the heck are boundaries anyway?

So I asked myself…

What do we know about a river’s boundaries?

[Note: slide your eye to wherever you see this symbol » if you want to skip the river specifics and get to the human take-homes!]

When hydrologists restore a damaged stream, we don’t set boundaries for the river. We just find the river’s own, already-existing, naturally-occurring boundary — “bankfull.”  It’s always there.

You’ll hear references to other boundary-sounding river features, for example the “low-flow channel” (but that changes annually if not daily) and the “one-hundred-year flood” (but that is a statistically-constructed theoretical estimate). Bankfull is the one and only visible physical boundary that a river has.

Knowing and respecting a river’s boundary is the most fundamentally important piece of the restoration process.

Only after we see and measure the river’s boundaries can we gather all the information necessary to understand “how the river wants to be.” Since basing design on the river’s innate preferences is what makes Natural Channel Hydrology so beautiful, effective, and sustainable, it is safe to say that everything hinges on understanding the river’s boundaries.

And — even with rivers — the natural boundary can be hard to figure out. Finding a river’s true edge is the trickiest art and science of Natural Channel Hydrology. Isn’t that an amazing parallel to human life? [Or at least to mine…!]

Hydrologists’ boundary-finding tools:

Each river tool for identifying bankfull is based on an important fact. (The river tools are marked by a square bullet. My ideas for parallel human tools are marked by an arrowhead.)

1. One way to identify a river’s bankfull boundary is to walk straight up out of the river — perpendicular to the flow — with your attention in your feet. When your toes begin to drop — to feel an even, level spot — that’s quite possibly bankfull.

Hydrologists take into account that bankfull is a geological feature. It’s a physical phenomenon within the river body — a level/depth — where the bank flattens out. It’s where the river just begins to spread out its waters when flow rises to flood levels.

» Like a river, our human boundaries are bodily phenomena. I mean, we can identify them by physical sensations. Here’s my approach:

Start somewhere inside yourself that you KNOW is “you,” and feel your way out into the world. When you feel a flattening out — there’s your boundary.

Alternately, start somewhere way outside of someone else’s private self, on nice level ground, and head toward that person’s psychic (or actual) space. When you feel the beginnings of a drop — a steep-ish slope down into their life — there’s your boundary.

I decided to test this approach: when is it okay for me to know something about my (18-year old high school senior) son’s social life vs. when should I mind my own business? He’s still in high school and lives in my house, so I feel fine establishing what time I can expect him home at night. But he is an adult (!), so I no sooner walk toward more details (like “who is he with?”) then I get a dropping in my stomach like when an airplane plummets. There’s the edge. When he was 5 or even 15, I still would have felt perfectly steady with the need to know who his companions were. Back then, I wouldn’t have felt that dropping sensation until I got to the desire to know, oh.. whether or not he ate candy (at 5 — yes I was THAT mother) or who he had a crush on (at 15 — God I tried NOT to be THAT mother but it’s harder than you might think!).

Note: I also could have arrived at this conclusion by starting inside myself — I don’t feel on even-footing until I know what time he will be home. Then I can sleep. So that’s where I can stop and say — this is my boundary.

2. Whenever possible, river professionals analyze historical flow data to determine which flow/energy level does most of the real work, i.e., is the peak in 2/3 of the years. If that flow’s depth matches the physical features we see in the field, then we have a little more confidence that we have spotted the river’s boundary.

Sometimes, bankfull’s physical line has been obscured (by a flood) OR there are conflicting flat places (maybe caused by periodic, artificial high flows released from a dam) OR the level area is so narrow that it’s hard to be sure if you’ve found bankfull (This is especially common in stream-types A, F, G, and even B. Click here to find out what kind of stream you are!). In those cases — and even when we think the boundary is clear — an hydrologist’s next step is to remember that “bankfull” also refers to an amount of water flow — a certain number of gallons moving down the channel each second. Bankfull is the flow that fills the channel to the point of imminent flooding.

A river’s water level represents its energy level — how much power it has. And there’s a really fascinating relationship between a river’s power and its boundary: the river does most of its “work” at the boundary-level flow.  Bankfull is the flow/energy level that formed the river channel, and it is this boundary-level work that continues to maintain the river’s shape:

Larger flows are more powerful, yes, but they occur infrequently. That’s why river channels are not big enough to accommodate their 100-year flood.

Smaller flows are more frequent, but they are less powerful. They don’t carve significantly into the surrounding earth or carry much of a load.

Where frequency intersects power is the sweet spot — the flow that made the river what it is — perfectly suited to its environment. On average, a river’s annual peak flow (usually the spring runoff but sometimes a quick increase in flow caused by a rainstorm) reaches bankfull or higher in 2 out of 3 years.

» I think that our true human boundaries also are associated with the real, meaty work we have done and continue to do in building ourselves to be who we are and who we want to be.

Don’t be fooled into thinking your boundaries have to do with the small many-times-a-day issues like whether or not your housemates put the toilet paper onto the rollie-thing in what you consider to be the proper direction.

Nor are your boundaries to be found in huge crises like whether or not your childhood best friend came to your mother’s funeral. Though such an event can cause huge damage, it’s not something you design your life around.

To find your boundaries, look at where/when/why/with whom/how you do your real life’s work. That’s what matters. What has shaped that work? Or, more exactly, how have you shaped yourself into this person you want to be? Protecting and creating those situations are your boundaries.

Kelly gets irritated that her husband is messy in the kitchen.  And it almost killed her when he had an affair. But her real work in life — creating a family in which all members thrive as individuals as well as have a safe, relatively simple, haven together as time goes by– wasn’t formed by divvying up the dishes or by one big promise. It was/is shaped by the connections forged in engaging altogether in open-hearted conversations, fun activities, and comforting routine. Perhaps these things make up the biggest part of the day only 1/2 or 2/3 of the time, but that’s where the real work is done, and so those are her boundaries. Her husband is good at those things, so — for now — it is worth it to her to work through the tiny and monumental issues that come up.

3. Another way to identify bankfull is to look for the “tree line” next to a river. This is somewhat of a misnomer because in some ecosystems, the perennial plants actually may be non-woody deep-rooted vegetation, but you can be sure that you will not find a river’s perennial friends inside the river’s bankfull boundary.

Hydrologists know that a rivers’ best friends — trees, bushes, and deep-rooted plants — need water and nutrients yet cannot live when constantly saturated.

When peak flow reaches or exceeds the bankfull level, water spreads out on the flat area adjacent to the channel — the floodplain — and the water slows way down. As soon as it spreads and slows, the river loses power, soaks the ground, and drops the load it has been carrying (which includes nourishing topsoil from upstream AND seeds!).

Bankfull flow is only seasonal — the river is significantly lower most of the year — so although they get regularly watered and fed by the river, plants at bankfull elevation are not drowned underwater most of the time. They have room to breathe. The best of all worlds and a truly symbiotic relationship. Trees need stream banks, and stream banks are stabilized by trees.

For this reason, perennials do not survive below bankfull elevation.Annual grasses — and shoots of all varieties — sprout and grow down inside a channel for one summer, but the next one or two spring runoffs will likely drown them or wash them away.

» To find our own boundaries, I think we humans can look at where our very best friends and allies — our very happiest and best version of “Everybody” — congregate. That’s where they stabilize us and we benefit them as well. And that’s where they stop, respecting our wants, needs, and preferences.

I would really love to hear your personal examples of how this tool (or the others in this post) plays out in your life. If you don’t want to comment below, you can email me (my gmail handle is betsypearsonpe — don’t forget the last 2 letters or it goes to a very nice woman in Indiana who is not me!)

4. Most importantly, we are wise to remember that each of the above conditions can be difficult or impossible to assess. When that’s the case, river guru Dave Rosgen’s favorite on-site learning activity is to ask his students to grab their sack lunches and picnic by the river. Try this yourself: Usually you will end up parking your bottom right exactly on bankfull because a river’s boundary is the most comfortable spot — level, perhaps next to a tree, near the water but dry… and high enough to look around.

» The same goes for humans: get comfortable. That’s where your real life’s work is done, and that’s your one true boundary.

What if you feel your boundaries aren’t established and you really need to FORM boundaries?

If you want to live like a river, then don’t worry about artificially, theoretically calculating or setting “appropriate” boundaries.

>>All you have to do is: your life’s work (and remember, work and play are the same thing in the realm of physics and rivers!).

When you are following your calling, your personal power automatically will carve your perfect boundaries into the foundation of your life.

Not only will your bliss (as our beloved Joseph Campbell called this kind of work) form a life with edges perfectly-shaped for YOU, but also it will create a “floodplain” to absorb the excess when life’s floods overwhelm you. And that will attract a community of supportive allies. And they will grow right next to you come drought or high water, and they will support you and you will nourish them and together you will create the comfiest spot around — your boundary.