If you’ve ever looked at a map of BAWG’s management area, you might have noticed something: it doesn’t follow roads, town limits, or property lines. Instead, it traces a wandering, organic shape that climbs over ridgelines and follows valleys. That’s because it’s not a political boundary at all — it’s built from watershed boundaries, and those are drawn by water, not by people.
Our management area covers 7.5 watersheds and numerous smaller subcatchments nested within them. Here’s what that means and why we map our work this way.
What exactly is a watershed?
A watershed (sometimes called a drainage basin or catchment) is simply all the land that drains to a common point — a stream, river, lake, or shared water system. Every drop of rain that falls within a given watershed is, in theory, headed toward the same water body, whether it soaks into the ground, runs off into a ditch, or trickles into a headwater stream first.
The boundary of a watershed is defined by topography, not by anyone drawing lines on a map. Walk along the highest points of land — the ridgelines and divides — and you’re walking the edge of a watershed. Rain that falls on one side flows down into that watershed; rain that falls just a few feet away on the other side of that ridge flows somewhere else entirely, into a neighboring one. That’s why watershed boundaries have all those curves and points instead of straight lines: they’re following the actual shape of the landscape.
Why 7.5 watersheds?
BAWG’s management area isn’t a single watershed — it’s a mosaic of 7 complete watersheds, plus part of an 8th (hence “7.5”). That eighth watershed extends beyond our management area, so only the portion that falls within our boundary is included. Within each of these watersheds are smaller subcatchments — nested drainage areas that feed into the larger watershed the way tributaries feed into a main river. Think of it like a set of nesting dolls: subcatchments drain into watersheds, and watersheds (fully or partially) make up our overall management area.
Mapping it this way means our work follows real hydrological divides throughout, rather than one clean, uniform basin. It’s a bit more complex to explain, but it accurately reflects the actual water systems we’re working across — from Eldon to Beach Point, draining to the Northumberland Strait.
Why we use watersheds instead of town, village, or county lines
It would honestly be a lot simpler to just set our boundary to a county line or a village limit. So why go through the trouble of mapping something more complicated?
Because ecosystems don’t care about political boundaries, but they very much care about water. A watershed is a functional ecological unit — everything in it is connected by the movement of water:
- Pollution travels downstream. Something that happens at the top of the watershed — a chemical spill, erosion from a construction site, fertilizer runoff — eventually shows up downstream, sometimes miles away and well outside any single jurisdiction.
- Species move along water corridors. Fish, amphibians, and many invertebrates depend on connected waterways to complete their life cycles. Mapping by watershed lets us capture those connections instead of arbitrarily cutting a species’ habitat in half at some line.
- Water quality reflects the whole basin. The health of our streams isn’t just about what’s happening right at the water’s edge — it’s shaped by land use across the entire watershed: forests, farms, neighborhoods, and everything in between.
By organizing our work around these watersheds and subcatchments rather than a city or county line, every project we take on tells a more complete story about how the land and water across our management area are doing — together, and system by system.
What this means for our community
This doesn’t change much about how you engage with BAWG day to day — keep exploring, reporting, and reaching out to us as you normally would! But it does mean:
- Everywhere in our management area matters, not just the water’s edge. Every subcatchment eventually drains into one of our watersheds, so upland habitats and land use matter just as much as what’s happening right along a stream.
- If you’re ever unsure whether a spot you’re exploring falls inside our management area, check our watershed map, or just reach out and we’ll sort it out — better to have the information than not.
- Areas near ridgelines are especially interesting, since ridges mark the transition zones between watersheds — including the edge of that partial 8th watershed that lies mostly outside our area.
- Over time, we hope to compare patterns between our different watersheds and subcatchments, rather than treating our whole management area as one big blob — so noting where you are matters.
Want to see the boundary for yourself?
Check out our watershed map to see the exact shape of our management area and the watersheds within it. Next time you’re out exploring, see if you can spot the terrain features — a ridge, a hill, a subtle rise in the land — that mark where one watershed ends and the next begins.
Happy exploring!