Revisiting a mega flood - Taroko Gorge Taiwan and super typhoon Sepat

[James Reynolds]

Last month I got the opportunity to go back to Taiwan and visit the stunning Taroko Gorge in eastern Taiwan. In my opinion this is one of the most amazing natural wonders of the world. Last year, within hours of typhoon Sepat making landfall just south of Taroko, Geoff Mackley and myself ventured into the gorge and witnessed the mother of all floods.

Revisiting the area last month I snapped some photos of the locations we were at during the height of the flood and they reveal the true extent of this extraordinary event. Check this out:

Looking downstream near the mouth of the gorge towards a temple dedicated to workers who died during the contruction of the road. The blue digger on the road gives a good idea of perspective.

The same view during the height of the flood. The water was surging over the road at times - the comparison between water levels is just gob smacking.

This is the infamous ledge which we walked out onto during the flood to film. It is VERY solidly constructed which is a good thing since this is where the water level was during the flood:

And finally, below is a picture of the road bridge at the entrance of the gorge on a nice day:

And during the aftermath of Sepat

That was one very crazy flood!

 

[Jose Garcia]

Great footage James! I hope to meet you in that basin in a few years from now...

Jose

 

[Glenn Rivers]

Stats on Flood?

Would you guys be able to place the locations in the flood pics on google earth or give the lat and long coordinates?

It would be interesting to see how that flood measures up to the world's largest. To determine this we need to know the area of the watershed draining to that point, and the discharge (i.e. in cubic meters per second).

Some of the pictures of the flood indicate supercritical flow, esp the interaction with the bridge piers.

Some of the most spectacular flood pictures I have ever seen!!!

 

[James Reynolds]

Flood

Hi Glenn.

I'll try and do that for you today and post the information here. I'd be very interested to hear your conclusions on this event!

 

[Greg Campbell]

Glenn, you got me going...

http://www.panoramio.com/photo/4546035
http://members.cox.net/geonerd/Ledge_of_Doom.kmz
I was hoping for more pictures of, or taken from, the ledge.

Cruise upstream in GE, with the Panoramio layer on. Or click on the Ta-li nested link in on the Panoramio page. The Park is amazing, and the gorge gives the canyons of the SW a run for their money.

-Greg

 

[Glenn Rivers]

More about the flood

Some info I have found....

-The name of the river is LiWu (I thought that the river would have the same name as the Gorge: Taroke, but apparently not.

-The river drains an area of about 600 square kilometers. The drainage area is probably more like 500-550 at the Eternal Spring Temple.

-Flow and sediment data has been taken since about 1960 at a location further upstream where the drainage area is only 435 square km.

-A flood caused by Supertyphoon Bilis on Aug 23, 2000 was about 3500-4000 cubic meters per second (CMS) at the gauging station, and likely closer to 4000-4500 further downstream. At least one flood between 1960-2001 was larger than the one caused by Bilis.

-Based on floods of other rivers in Taiwan, a flood of at least 6000 CMS is possible on the lower part of the LiWu river.

-James Reynolds pictures of the Sepat flood taken on the E river bank looking S towards the eternal spring temple, as well as the pics taken looking down at the overlook showing the timber snagged in the handrails indicate that the river had receded by at least 1 meter when the pics were taken. That would indicate that the flow was down to about 80% of the flow at the peak of the flood.

-The pics take at the bridge across the LiWu to the Taroke visitor center 2-3 km downstream of the temple suggest that this is the best location to estimate the river's flow. The river is about 110 meters wide under that bridge, but I can not tell exactly how high the bridge is.

Did James take the pics at the downstream (Visitor Center) bridge before or after the ones taken upstream near the Eternal Springs Temple? Also, does James know how to find out the height of the bridge.....maybe the info is online but I do not know were to look or how to read it?

I am still going to estimate the flow, but the time of the pictures and the height of the bridge would be a great help

 

[James Reynolds]

Flood

Hey guys - sorry it's taken so long for me to get back on here.

Here's so more information which I hope will help. First of all here's a link to a pic of the bridge near the visitor centre on a nice day:

http://www.typhoonfury.com/Pics/Revisiting%20Mega%20Flood/E%20normal%20800.jpg

Now here is a link to the video I posted from the event:
http://www.youtube.com/watch?v=Sv2O1DU0jX4

Towards the end of the video you can see a vehicle driving over the bridge, hopefully this will help with estimating how high the bridge is. The photos/film at the bridge were shot about 45 minutes after the ledge.

Taroko Gorge is spectacular - a real natural wonder of the world. The Sepat event will be part of a documentary which will be broadcast in US later in the year so I'll keep you posted on that.