Best Practices in Civil Engineering
I walk my dog, Pepper, almost every day. She’s an aging German Short Haired Pointer, the kind you’ll often see in cartoons pointing at Buggs Bunny. She’s a hunting dog who prefers tracking a stag, cornering a rabbit or chasing a squirrel to any other activity. Other dogs are merely a nuisance to be sniffed then dismissed once it has been ascertained that they are definitely not a rabbit or deer. As for humans, they are good for two things, food and as hunting partners. I am her nominal owner and she acknowledges that fact by demanding various treats when it’s not time to patrol the neighborhood or by barking at me to announce she’s returned from a visit to the back yard or occasionally demanding an ear scratch or belly rub when she’s in the mood. When she’s indoors she mostly sleeps but outdoors, she’s alive.
As I’ve said, Pepper is a hunter. When she hunts rabbits she uses me to beat the bush for her. She knows that if I make enough noise at the front of my fenced in garden, whatever rabbits that might be there will beat a hasty retreat through holes they’ve dug under my fence. She knows where those holes are and will be there waiting. She’s caught a few rabbits that way and considers the chase to be great sport. She understands and is a part of the nature she lives in, unlike most humans who see nature as something to be cut down and paved over or at least preserved as a park suitable for picnics.
As we wander the woods she’s taught me a lot. She points out dear runs that would otherwise escaped my eye and directs my attention to various fresh animal scat, only some of which I recognize. She does not have the best eyesight. This is not from her advanced age but is, rather a characteristic of her breed. A stationary deer not 20 yards downwind from her would remain unnoticed. She does have an incredible sense of smell, however. I have to assume this since I can’t smell the passage of a deer five minutes ago, never mind in the last couple of hours. She can and will double back until she establishes the direction of travel then it’s only a mater of time, minutes in some cases, hours in others, before we corner the majestic animal and Pepper freezes, then points, her noise aimed motionless at the deer, her tail stretched and unmoving behind her and her right forepaw lifted in the classic position.
These last events don’t happen every day, once or twice a year, these days, as the woods become filled with new human construction. Where we once, a few years ago, patrolled a well worn dear run, we now patrol a cull de sac in a tony new subdivision. Where we once had to ford a small brook twice we now keep our feet and paws dry on paved bridges. This change in the local eco-system has brought about other changes that Pepper has been happy to point out to me.
The deer run we used to patrol ran beside a swampy pond, across a road, then along a broad swamp before crossing and recrossing near a rocky outcropping. It’s this latter section that has been profoundly changed. It’s the broad swamp that has changed the most as a result of human habitation.
The broad swamp is fed by several small streams that tumble down two sides of a small hill. The swamp empties from two sides. One side empties through a very small culvert that passes under a local road. The other end empties into a deeper channel that, now, passes through two large culverts that pass under the cul de sac. It’s this last development that caused a family of beavers to decide that the broad swamp had potential.
Over a period of a full year they cut down some very large trees and blocked the exit near the first large culvert. It’s astonishing how large a tree, 8 to 10 inches in diameter, can be cut by a beaver. Unfortunately, one of these trees, left for the winter winds to fell it, came down over the cul de sac and caused a great deal of animosity, not from the residents but from the town’s road crew who proceeded to demolish the dam with a backhoe. Two hours of human destructive effort took about three days for the beavers to repair.
A month later the backhoe was back but this time it took less than 3 hours for the beavers to make their repairs. This cycle repeated itself at least three more times. Then it stopped. As we walked by, Pepper would snicker as only a canine with superior intelligence can. She’s not interested in beavers as prey. I think she thinks of them as almost co-equals in the forrest. When we encounter one swimming, she’ll point then let out a soft, woof, then move on. The beavers don’t break their stride to acknowledge her greeting. The second year the beavers were in residence Pepper pointed out to me that a beaver was casually swimming a full hundred yards down stream near the second large culvert. I thought nothing of it until Pepper made me look over the overgrown edges of the bridge. There was high water on one side and barely a trickle on the other. The beavers had damned the upstream side of the culvert in an area that was too steep to create a working beaver pond. Why?
The beavers had figured out that by creating another dam down river from their main dam the water level wouldn’t drop so precipitously and they could repair any damage in a hurry. I’m sure the road crew hasn’t figured this out.
The deer run continued on the other side of the road past another shallow pond. A small culvert, perhaps no more than two feet in diameter runs from the broad swamp that was now a beaver village, to the shallow lake. Pepper pointed out that the beavers had damned that exit as well. Next we walked down a largely unused portion of the deer run, the deer having blazed new trails elsewhere. At the far end of the shallow pond, the beavers also damned that so that regardless of where the dams might be breached, there would never be a serious loss of water in the main beaver pond unless at least two of the dams were breached at the same time.
This is clearly an example of best practices for MIT educated civil engineers.