Pattern Languages for Stream Restoration
February 02, 2013
My first experience with SHARE was in 2008; it was my Junior year at Nazareth, and I was back in Maine for a few weeks. I volunteered, enjoyed it, and was hired the next year. That was the era of Stimulus funding, and for the next two years, SHARE pulled off close to 40 road-stream restoration projects annually. We were busy. Busy almost exclusively in the West Branch Machias and Old Stream watersheds. We ended up replacing the existing round culverts with open-bottom arches or decommissions on almost every perennial stream in those watersheds.
Drive around for a few years on a restored watershed, and your idea of what a normal crossing looks like starts to change. I’d gotten spoiled, seeing open-bottom arches everywhere I went. Shortly thereafter, we’d begun surveying the Narraguagas and East Machias watersheds for potential projects. All of a sudden, I was reintroduced to what remains the status quo as far as road-stream crossings go in Maine. Undersized, perched, round pipes. Which, to the uninitiated, is pretty normal. Nothing worth looking at. Even if you do see it, it’s a small blemish on an otherwise healthy stream. If you’re reading this, you’re already probably well aware that this isn’t the case. There are thousands of these blemishes in Downeast Maine, and each of them affects the hydrology of the stream network. Combined, SHARE’s ecologically designed road-stream crossings have had a massive impact on the health of our streams, especially when compared to the un-ecological crossings that were present before restoration.
I realize now that one of the more difficult, and maybe more important parts of restoring a watershed is changing the vocabulary of those responsible for constructing the road-stream crossings in the watershed. If you can’t describe what makes a road-stream crossing good, then you have little chance of installing one well. Christopher Alexander describes this beautifully in his book The Timeless Way of Building:
When a person is faced with an act of design, what he does is governed entirely by the pattern language which he has in his mind at the moment… We must make each pattern a thing so that the human mind can use it easily.
As we begin to correct individual crossings, we start to have an effect on the network as a whole. Each instance of a crossing which permits the stream’s natural hydrology is a step in the right direction.
The small patterns produced directly by the individuals and repeated over and over again. The large patterns generated indirectly, by the gradual incremental repetition of the smaller patterns.
Eventually, we have a healthy, functional watershed. And without directly trying to, a watershed which supports the life of native species we value so highly: Atlantic salmon, Brook trout, Alewives, etc…
What does that vocabulary looks like? For Downeast Maine, maybe it includes some of the following:
- Open-bottom arches
- Stream simulation
- Natural elevation
- Bankfull width channels
- Sediment transport
- Riffle-pool sequence
- Point bars
The one thing we can be sure of is that as we learn and improve our understanding of Maine’s streams, our vocabulary will evolve. We want to improve this list. If you have something to add, or a word to contend, we’d love to hear from you.
And finally, a beautiful quote from the ‘Timeless Way of Building’ that I didn’t, but maybe should have expected in a book about Architecture.
The word ‘stream’ describes a pattern of physical space and a pattern of events, at the same time. We do not separate the stream bed from the stream. There is no distinction in our minds between the bed of the stream, its banks, its winding configuration, in the land, and the rushing of the water, the growth of plants, the swimming of the fish.