As we stepped out of the car, mosquitoes closed in. Having driven deep into the wilds of northern BC, I don’t know what else I should have expected. Fully seventeen hours north of Vancouver we had turned off a paved road onto an unnamed logging road with a shabby old sign for the “Derrick Creek Rec Site 6km,” one of the many gravel roads built for the giant logging trucks that prowl this far northern forest with their loads of valuable, recently chopped down, trees. Fallen trees that lay across the road had been sawed through by helpful earlier travellers. Only one was recent enough to block our path but we were able to lift it and pivot it off the road.
Mark slung a rucksack at me and and said, “Come on. This had better be good.” We donned wading boots and plunged into the forest.
The reason we were here was a cartographer’s dilemma. Derrick Creek, as I had first seen it on the Canadian topographic map poetically named “103P: Nass River” was a waterway that flowed south out of Derrick Lake and went some ten kilometres south to the Cranberry River.
103 P “Nass River,” 1989 1:250,000
The Cranberry, one of northern BC’s important inhabited rivers since time immemorial, and heart of the traditional lands of the Gitanyow First Nation, is shown on this same map winding back and forth, meandering its way westward, down to the mighty Nass, a river so provincially significant that in the coding of BC’s major watersheds it bears the halcyon number “500.”
103P “Nass River,” though, is a pretty small scale map, which means that while it covers a lot of territory it is not in any sense “zoomed in,” as we might say nowadays when we can pick up a phone and use our fingers like little stretching tools to zoom in on Google maps. 103 P, produced in 1989, is at the relatively undetailed 1:250,000 scale.
103 P 10, “Cranberry River,” 1984, 1:50,000
When you look at the more detailed 1:50,000 scale map 103P-10 “Cranberry River” (Second Edition, 1984, the most recent you can get), Derrick Creek, which the Gitanyow people call Xsimihletxwt (“green creek”), is visible in more detail. It flows out of Derrick Lake, passes around the letters WM, skirts a small swamp and goes into a small unnamed lake (near “23”), then flows south, crosses under the highway and into Bonus Lake. This is how Derrick Creek proceeds to the Cranberry. Quiet, reliable, placid. Probably infested with beaver.
(Bear that small unnamed lake near the “23” in mind. We’ll call it Unnamed Lake 1. It will become important later on.)
So, all good. Except, apparently no longer true.
Today, if you look at a online map produced by Natural Resources Canada, or Open Street Map, what you will see is that after leaving Derrick Lake, the creek goes south for a bit, then just before hitting that unnamed lake it appears to change its mind, and it heads west. It heads west, passes under the highway, through a second and bigger unnamed lake and goes into the Nass. No Cranberry River. No Bonus Lake.
Detail of the area where Derrick Creek has apparently changed course
This could be fairly significant if you told your friend “Lets go fishing at the mouth of Derrick Creek,” and she showed up at the place on the Cranberry, the place where a streams still flows in but apparently we don’t call it Derrick Creek any more, and you showed up on the Nass at that new Derrick Creek, like a second location of your favourite restaurant, recently built and all glitzy, but somehow lacking the charm of the original, and somehow too even the food doesn’t taste as good. Especially the fish.
In short, Mark and I are here to figure out what happened. Was it an old mapping error? Did Derrick Creek never flow to the Cranberry? Or did the stream change course, some time between 1989 and 2018?
You’ll also notice on the map above a swamp at the point where Derrick Creek allegedly changed course, and this may be helpful. Strange things happen in swamps. Water flows slowly and in multiple directions. Beavers do stuff, small actions of chewing down trees and pushing them into certain places in the creek flow, small acts that add up to big changes in the end. We’re here to look for evidence.
The old logging road that Mark and I now set off on, on foot, is overgrown with alder. Two old tracks of vehicle tires are still visible on the ground, and the dog weaves ahead easily along them, while at the height of my face alders slap me repeatedly. Which is welcome, because it’s brushing off the mosquitoes. It’s clear that no one had driven this road for about ten years.
After a few minutes of breathless alder crashing we come to an old log landing, a clearing in the forest where cut trees were stockpiled before loading onto trucks. There’s an old camp here with a small stove cunningly made from a steel barrel. We strike off at a bearing of 290° through a forest of evenly spaced pines, trees apparently planted some 40 years before. A few minutes later we hit the old channel of Derrick Creek, just above Unnamed Lake 1. It is neither stagnant nor non-existent. It is a small, burbling little stream. It is small, less than a metre across, and flowing with no great volume, but it does exist.
Why does this even matter?
Well, should the map looks like this (the old way)…
or like this (the old way)?
It’s a big difference.
But, it should be easy to decide. Here are the sites we need to visit.
Roads, streams and lake from current provincial data; “indefinite” streams shown in lighter blue. Contours from SRTM 1″ coverage.
- Culvert 1, to observe what’s coming down the “old” Derrick Creek and flowing into Bonus Lake
- Bridge 1, should be the same as what we see at Culvert 1
- Bridge 2, to observe the contribution of an unnamed tributary that heads straight to Unnamed Lake 1
- Bridge 3, to observe the outflow from Derrick Lake
- The Split, to see what happens there
- Culvert 2, to observe the flow in the “new” Derrick Creek, which, incidentally, is classified as “intermittent” in the provincial Freshwater Stream Network data
In the nineteenth century the standard way European explorers in Africa or Afghanistan decided which was the primary tributary of a river was to measure the flows of each at the confluence. This was height of the patriarchy, I know, but their simple science had a reasonable method: the stream contributing the greater amount of water got the name of the river, and up it the intrepid explorer went on the continuing quest for the headwaters. Admittedly this usually resulted in boundaries being drawn by Great Powers, and odd nation states being created for the purposes of the same said Great Powers, but we’re not doing any of that here. We know this is Gitanyow territory. We just need to figure out where Derrick Creek. really goes. It’s a cartographer’s dilemma and a cartographer’s errand.
And our problem is a bit different from that of the nineteenth century explorer. We already know where the headwaters are. Derrick Creek comes down from Derrick Lake. We’re trying to figure out where the resulting flow goes. But we can still use the principle that where more water flows, that’s the main stream. We’re just doing it … downhill.
Working our way upstream we come to the key place: on the edge of a large swampy clearing, Derrick Creek is flowing in from the east and splitting in front of me into one fork that continues west across the swamp and, presumably, eventually to the Nass, and one fork that lazily turns south and feeds this small stream that goes to unnamed lake #1.
Mind you this is not swiftly flowing water. Everything is at the same level, no doubt due to beaver dams. So the place the creek divides is more of a pond with two outflows. There’s no current to observe.
Mosquitoes close in as I survey the water and balance precariously atop hummocks of grass with water between them. We’re going to call this place The Split.
Down in the direction of Unnamed Lake 1, I can hear the water spilling over what is probably a beaver dam and beginning its descent. Looking at the surrounding forest I can see that there is a significant historical channel this way. To the west the swamp continues on as a wide opening in the surrounding forest and its unclear how the stream leaves it. At any rate it seems not a lot of water is flowing through here, at least not on the surface. Subsurface flow is possible.
I’m not able to measure how much water is leaving via the two exits at The Split. However, I have a bit of a proxy. If we go look at Culverts 1 and 2, we should be able to compare the flow through them and decide which is the bigger stream. These two points underneath the highway represent the only candidates for how water in Derrick Lake can leave the area, so they should tell us where the major stream is.
On the way out however it seems worthwhile to check the flows at Bridges 1, 2 and 3. And this introduces more uncertainty. At Bridge 1 we have a good flow of a creek a few meters across and fairly shallow, say 15 cm or less. At Bridge 2 we have the same thing, suggesting that most of what’s flowing down to Bonus Lake in fact comes from this unnamed tributary, and not from Derrick Lake at all. At Bridge 3 is the actual outflow from Derrick Lake and our first look at what is undisputedly Derrick Creek. The water here is sluggish. It might be a metre deep in the middle but there’s little flow. As if Derrick Lake isn’t really draining much at all.
So it’s on down to Culvert #1, where the “old” Derrick Creek flowed under Highway 37 and into Bonus Lake. Mosquitoes declare themselves in force, and drive us into amusing looking but useful white bug jackets.
Culvert #1 is impressive. It has been engineered for major flow, and is in fact enormous twin culverts, each about 4 metres in diameter. (They are such a major work of engineering as to have a highway sign, which identifies then as “Derrick Creek North Culvert” and “Derrick Creek South Culvert.” This suggests the BC Ministry of Highways has not been informed by the BC Ministry of the Environment about the new direction the creek took.) You could drive a small car through either of them. The flow of the creek, although decent, barely fills the bottom of these huge structures.
So now we visit Culvert #2, the culvert where the “new” Derrick Creek passes under highway 37. This is a shocker. We can barely even locate it because of the tiny size of the drainage and the almost inaudible water flow. The GPS is called in to confirm we are in the right place.
There’s almost no water here. And culvert #2 itself is small, less than a metre in diameter. No more than a trickle of water flows through it.
It’s plainly impossible that Culvert #2 carries is the main flow of Derrick Creek. The flow from The Split toward unnamed lake #1 may be lazy, but it’s more than we see here. Culvert #1 is carrying much more water, a real stream.
It looks like something is badly awry with the Freshwater Stream data for Derrick Creek, and I’m going to go with the old scheme shown on the maps from the 1980s: Derrick Creek flows out to the Cranberry.
But there’s a third possibility. What we saw at bridges 1, 2 and 3 suggests that most of what used to be, at Bonus Lake, called Derrick Creek comes from that unnamed tributary, and there’s actually very little water flowing out of Derrick Lake. It’s easy to imagine that before the current generation of beaver dams the outflow of Derrick Lake was sufficiently connected to this active stream as to give it its name, but that even then most of the water came from the unnamed tributary. There may need to be another reconnaissance one day. I can see it now: a canoe, little stream gauges, perhaps a drone….
Back in the car, Mark seizes the packet of topographic maps we’ve been using for reference and says, “I know how this thing can be really useful.” He begins swatting bugs with it.