Creek Obstruction Removal

A tangle of debris was left in this section of the creek channel following a flood in early 2011.  More material has collected since that time and the resulting dam has almost completely blocked the channel.

If left in place, this blockage will result in a major rerouting of the stream channel.  That option didn’t seem right for this particular area, so I decided to remove the debris and reopen the old channel.

Cutting a couple of key logs freed everything else, so it was just a matter of pulling pieces free and moving them out of the channel.  Most were just set out on the bank.  I’ll move everything to one of the brush piles later in the fall. 

Leaves and other organic material trapped by the obstruction were mostly well composted.  That compost will make its way downstream during the next big rain event.  Decomposing leaves are a primary source of nutrients for headwater stream systems.  Ideally, small pockets of leaves are left along the entire stream length instead of all piling up in one location.

The flood water will now make its way around to the left instead of jumping out of bank and running overland to the right.  The floodplain affected by out of bank flood water contains an assortment of wildflowers.  Loss of topsoil during flood times and direct damage to plants by the flood water threatened to destroy most of those plants.  High water may still makes its way across the flood plain, but that will happen much less frequently now that the blockage has been removed.

Creek blockages are natural occurrences that shape the development of a stream.  I normally leave these obstructions to run their natural course.  In this case, I considered the blockage to be somewhat unnatural because of the source of most of the original material.  The biggest part of the trees and branches creating the original tangle were from logging debris thrown into the channel somewhere upstream of Blue Jay Barrens.  A flash flood event dislodged the mess from its upstream resting place and relocated it here.  Without the addition of this artificially created debris, the obstruction would probably never have formed.  I accept changes created by natural events, but I do my best to correct man-made disasters.

Tree Down but not Out

The record flood we had during the winter created several new obstructions in the creek.  A typical obstruction is composed of dead tree parts.  There may be anything from a full log to a bunch of dead leaves.  The material decomposes over time and the mass looses its integrity. Eventually, another flood deconstructs the obstruction and carries it on down stream.  Occasionally there’s a different type of situation and the inevitability of the outcome is not quite so certain.

The key piece in this blockage is a still living tree.  The root ball that once perched on a slab of bedrock just above the bank, slipped off of the rock as a unified mass and landed in the center of the creek channel.

The bulk of the root system is still enclosed within the original block of soil.  The soil is able to wick up enough water from the creek to keep the roots healthy and the tree hydrated.  Eventually, the combination of rain and flood water will wash the soil from the roots.  When that occurs, the roots will dry out and die.  There are too many variable involved to predict just when that might happen.

In the mean time, the tree is growing.  There are several healthy shoots developing from the base.  The tree roots that are in contact with the stream bed will most likely have the greatest longevity.  Basal sprouts tend to have the greatest chance of surviving on a fallen tree.  Conditions may be right to give these sprouts many years of growth.

At the moment the entire tree is producing healthy growth.  Production of new growth increases the ability of the tree to snag and retain debris floating in the current.  The growing tree becomes responsible for a growing obstruction.  Instead of losing stability as a result of decomposition, the tree and its collection of debris becomes more firmly positioned in the creek channel.  This could result in a drastic and long term change in the nature of this section of creek.

When a tree goes horizontal, the top of the tree loses its ability to act as a growth regulator.  Every bud along the trunk is free to make its bid for leader.  The rapidly growing sprouts emerge in clusters that are ideal for capturing small bits of floating debris.  If it can maintain life for a couple of years, the tree will make a formidable barrier.

It’s clear to see that the tree is anchored firmly in place.  The tree held its position against flood water strong enough to move those slabs of rock.  The tree not only stayed in place, it effectively kept the rocks from moving any farther downstream.  If the tree could hold against the record flood, it should be able to easily maintain itself against the normal high water levels.  This will be an interesting situation to watch.