Friday, November 16, 2012

Ketchum-area whitewater park has conservation foundations

Wood River Land Trust lobbies for health of river, floodplain


By KATHERINE WUTZ
Express Staff Writer

Courtesy graphic This graphic shows the area of the Big Wood River where the Wood River Land Trust and the city of Ketchum are proposing a joint recreation-conservation project to provide fishing and whitewater rafting while preserving the health of the river.

 

Though recreationists may rejoice at the thought of the whitewater park proposed for the Hulen Meadows area north of Ketchum, staff at the nonprofit Wood River Land Trust said they are excited about the conservation opportunities.

Land Trust Executive Director Scott Boettger said during an interview on Thursday morning that every year, homeowners north of Ketchum apply for emergency stream-alteration permits during high flows to harden the banks.

While bank hardening prevents the homeowners’ backyards from flooding, Boettger said that it causes a “ripple effect” in which the river is prevented from flooding or meandering as it naturally would to deal with increased velocity.

This, in turn, causes homeowners downstream to need to harden the banks there, he said. And once too much of the bank is hardened, the river has to go somewhere—so it incises, or digs down into the channel.

While that might not sound like a threat, Boettger said that a severely incised river will actually separate from its floodplain. That means that wetlands that used to house songbirds and other riparian life no longer exist, and the high velocity of the resulting stream makes the water less hospitable to aquatic life as well.

But keeping the stream from incising and finding other ways to reduce the river’s velocity can prevent all of that, Boettger said.

“You have to find spaces where you can let it spread again,” he said.

What the land trust proposes is building new drop structures, or angular configurations of rock that essentially “break” the water. The structures form a V that points upstream, and when the water hits those structures, it deposits sediment before plunging into a small pool just downstream.

Wood River Land Trust spokesman Trey Spaulding said in an email that these structures, similar to ones that have been constructed just below the Bullion Bridge in Hailey, create excellent trout habitat and fisheries. Boettger said that the structures mimic natural wood debris pile-ups found in unaltered streams.

But the structures also create the rapids that the city of Ketchum is hoping to capitalize on, forming a whitewater park north of town. The city of Ketchum, along with the land trust, applied for a Recreation and Public Purposes patent on two parcels of land near Hulen Meadows in 2008, which would grant deed-restricted ownership to the city.

The first parcel covers 210 acres from the Sun Peak Day Use Area to the Lake Creek trailhead, while the second covers about 105 acres at the confluence of the Big Wood River and Warm Springs Creek.

If the agreement is approved, the land trust would oversee riparian, vegetation and habitat restoration, while the Ketchum Parks and Recreation Department would oversee management and maintenance of recreation components—including whitewater rafting near the Sun Peak picnic area.

Boettger said that drop structures were originally constructed in this area in 1991, when the Idaho Transportation Department realigned Highway 75.

According to a letter from Bozeman, Mont.-based Geomax Engineers to the Blaine County Planning Department dated March 11, 1991, engineers at the time were concerned that the channel created by realignment would erode nearby banks, cut off meander loops which had decreased water velocity in the area and essentially “capture” the river, preventing it from being able to naturally absorb high flows.

Boettger said that the drop structures originally constructed have since eroded—except for one, which could be rendered useless by severe erosion due to a future flood. If this structure were to erode, he said, the stream could be severely threatened.

“Then you are going to have an incised, captured river,” he said.

He said he is optimistic that the patent would be granted within the next few months, so that construction could begin as soon as possible.


Kate Wutz: kwutz@mtexpress.com

 

 




About Comments

Comments with content that seeks to incite or inflame may be removed.

Comments that are in ALL CAPS may be removed.

Comments that are off-topic or that include profanity or personal attacks, libelous or other inappropriate material may be removed from the site. Entries that are unsigned or contain signatures by someone other than the actual author may be removed. We will take steps to block users who violate any of our posting standards, terms of use or any other policies governing this site. Use of this system denotes full acceptance of these conditions. Please review the full rules governing commentaries and discussions. You are fully responsible for the content that you post.

The comments below are from the readers of mtexpress.com and in no way represent the views of Express Publishing, Inc.

You may flag individual comments. You may also report an inappropriate or offensive comment by clicking here.

Flagging Comments: Flagging a comment tells a site administrator that a comment is inappropriate. You can find the flag option by pointing the mouse over the comment and clicking the 'Flag' link.

Flagging a comment is only counted once per person, and you won't need to do it multiple times.

Proper Flagging Guidelines: Every site has a different commenting policy - be sure to review the policy for this site before flagging comments. In general these types of comments should be flagged:

  • Spam
  • Ones violating this site's commenting policy
  • Clearly unrelated
  • Personal attacks on others
Comments should not be flagged for:
  • Disagreeing with the content
  • Being in a dispute with the commenter

Popular Comment Threads



 Local Weather 
Search archives:


Copyright © 2014 Express Publishing Inc.   Terms of Use   Privacy Policy
All Rights reserved. Reproduction in whole or in part in any form or medium without express written permission of Express Publishing Inc. is prohibited. 

The Idaho Mountain Express is distributed free to residents and guests throughout the Sun Valley, Idaho resort area community. Subscribers to the Idaho Mountain Express will read these stories and others in this week's issue.