Thursday, April 23, 2015

Beyond the Sinkholes - the Ephemeral Waterfall

The most interesting part of the Wodehouse Karst system to me is beyond the sinkholes, where the flooded creek flows down the smaller valley further south and creates a temporary or 'ephemeral' waterfall into Bowle's Gully at the Beaver Valley Ski Club.

This is the ephemeral waterfall in Bowle's Gully after a period of heavy rain in the fall.  There's just a little flow over the falls, and I was able to get quite close for pictures - though it was quite an adventure to get there!

But normally the creek flowing down the southern valley beyond the main cluster of sinkholes is a very small stream, just gathering local runoff from a few farm fields and a wetland.

It ends in this very small sinkhole at the ski club, where the water trickles into the cracks between the rocks, and emerges far down the slope as a spring.

The channel in the limestone beyond that, between the ski chalets, is dry - usually for about 50 weeks a year.

But during the spring flood creating the temporary lake (on the left), the excess water flows into the small stream valley southwards (towards the right), flooding that valley and raising the water level in the stream dramatically.

The stream swells to many times its normal size.

It flows across that small sinkhole without ever even noticing, here 2-3 feet deep and 30 feet wide,

and floods the normally dry stream channel with a torrent of rushing water, heading straight for the edge of the cliff.

And in the spring, this is the waterfall that results.  After last year's heavy winter and extended spring runoff, the waterfall lasted nearly 6 weeks, the longest I've known.

As you can see from the water swirling toward my feet, I could not even begin to get close to the bottom of the falls to get a picture like the first one above; the entire foreground of that picture was flooded with a foot of water bouncing off the boulders.

Finally, this is Bowle's Gully, a very steep sided ravine occupied today by the Avalanche ski run at the ski club.  This is one of those runs I would look over the edge at and say 'no way'!  The waterfalls is around the corner to the right.  But thousands of years ago when glacial meltwater was pouring over this waterfall all year round, it carved out this ravine eroding a steep-sided valley down to the right in the picture, leaving a cliff along the top, and slopes cut through the soft Queenston Shale below.

It's the entire Wodehouse drainage system that intrigues me, from the springs where it originates, through the sinkholes and the temporary lake created by spring runoff, to the ephemeral waterfall, to the glacial valley below.  The waterfalls is a spectacular sight, but then the stream dries up, the sinkholes upstream handle all the remaining flow, and the waterfall disappears for another year.  A small creek is left tumbling through the valley pictured above after emerging from the spring on the slopes.


14 comments:

  1. The terrain of the Escarpment always draws me back. It's been too long since I've been there.

    ReplyDelete
  2. Another excellent post about the geography of your area.

    ReplyDelete
  3. Yup, it's difficult to get a decent waterfall shot when it's running so full and spraying everywhere.

    ReplyDelete
  4. Your waterfalls look beautiful! We have karst topography here in the Shenandoah Valley, resulting in a number of large caverns. Last week a big sinkhole opened up in the middle of Interstate 81, holding up traffic for a day and a half. Everyone had to detour through the towns.

    ReplyDelete
  5. The waterfall is wonderful. What a great shot. You had a bit more snow yesterday than we did. : ) And a lot colder too. I thought 32 was a bit cold for this time of year but it was really cold by you!!!

    ReplyDelete
  6. Wonderful photos. I would love to visit your area and see all the marvelous waterfalls.

    ReplyDelete
  7. Wonderful post and photos ! Oh WOW ! Still snow there in the forests ! None left in our valley forests thankfully ! it has been years since I have been up that way still very pretty ! Thanks for sharing , Have a good day !

    ReplyDelete
  8. Nice waterfall pictures, for sure. I enjoyed learning more about the area. We've got cold weather and a lot of snow coming to our mountains for the next week or so, but we've been snow free and warmer than normal for ages. :-)

    ReplyDelete
  9. Great documentation of the seasonal cycle in the watershed! The photos are gorgeous!

    ReplyDelete
  10. Spring thaw can sometimes be a real problem. We didn't get enough snow to worry about this year. It is a great selection of photos you are sharing.

    ReplyDelete
  11. even with little green, it is still a beautiful area!!!! spring thaw = mud season!!!!

    ReplyDelete
  12. Most interesting. Here in southeastern Minnesota we live in a major unglaciated/karst region with few lakes, disappearing rivers and lots of caves and sinkholes...:)

    ReplyDelete