17-12-20 Bigwood River Flood 5 Roland.jpg

The Big Wood River flows at flood stage near Hailey in the spring of 2017.

The Big Wood River has become a neighborhood.

More than 300 homes sit near or on the riverbanks between North Fork, north of Ketchum, and the Bullion Street bridge in Hailey, according to an analysis by the Idaho Mountain Express that used Blaine County’s mapping and property records databases.

The pace and scale for development of riverfront property peaked in the 1990s, but new homes are still being built, according to the analysis.

People have altered 52 percent of the river’s 45-mile span from North Fork to Magic Reservoir, according to a 2016 study. In 1969, a study determined that people had altered 22 percent of the riverbanks, though it examined a 58-mile stretch of the Big Wood.

These homes are found in North Fork, Chocolate Gulch, Eagle Creek, Fox Creek, Hulen Meadows, Adams Gulch, Ketchum, Lane Ranch, Broadway Run, Gimlet, East Fork, Golden Eagle, Starweather, Zinc Spur, Deer Creek and Hailey.

Some of them are among the Wood River Valley’s most elegant and extravagant: Former U.S. Secretary of State John Kerry has a home on the river near Adams Gulch, while rock icon Steve Miller owns riverfront property at Eagle Creek. He recently listed it for sale for $16 million.

Other riverfront property owners include real estate magnate Sam Zell and former Lehman Brothers CEO Dick Fuld. When author Ernest Hemingway was searching for a home in the Wood River Valley in the 1950s, he bought one overlooking the Big Wood in Ketchum.

Blaine County and its cities have strict ordinances prohibiting hillside development in the valley. Riverside property has emerged as extremely valuable real estate, and a major boon to local governments’ tax bases.

Katherine Rixon, a real estate agent with Keller Williams Realty, said property in Ketchum that’s along the Big Wood can add up to $1 million to its value. She and her business partner, Rob Cronin, are listing properties with river frontage between $1.29 million and $7 million.

“The key thing is that there’s a limited supply of Big Wood River frontage,” Rixon said. “It’s one of the prime features of our area, along with Bald Mountain. They’re not making more of it.”

The vast majority of riverfront homes were constructed in the 100-year floodplain and on wetlands, though in the past 30 years the cities and the county have imposed development restrictions that include riparian setbacks.

In the unincorporated area, development can’t occur within 75 feet of the high-water mark. In Ketchum, it’s 25 feet. In Hailey, the setback is 100 feet.

Still, all these neighbors have made it much tougher for the Big Wood to act like a river.

Every river performs basic functions, and the work entails more than just flowing between banks.

The Big Wood is a system comprising the sediments, geology, climate, human-initiated changes, vegetation and precipitation within its basin.

Fueled by gravity and discharge, the Big Wood has a lot of energy to disburse and great quantities of sediment and other materials to transport downstream. That includes sands, clay and silt, as well as gravel, rocks, boulders and logs.

It is forever seeking equilibrium, which is a state of balance where it has capacity to carry that sediment load and send its waters toward the sea.

The river also wants to change shape to meet its demands. It likes to meander over the alluvial plain and alter its channel width and depth. Its velocity will increase depending on slope and other factors, and that can accelerate erosion. The homes make that meandering difficult, said Doug Megargle, regional fisheries manager for the Idaho Department of Fish and Game.

“You can’t mix urbanization into a natural-process river function,” Megargle said. “A naturally functioning river tends to migrate back and forth over the valley floor.”

Flooding that the Big Wood experienced last spring is an example of a system out of balance.

Following last winter’s record snowfall, the river was engorged with water. The fast-moving, turbid waves lacked access to its floodplain, and it found the low-elevation places of least resistance where it could overtop the banks.

The flooding left lots of woody debris, formed new channels in the river and deposited gravel and sand in new places. The river changed directions in some places.

Parts of the Della View subdivision in Hailey and Gimlet, south of Ketchum, were squarely in the crosshairs. Those areas were under water for more than two months, while many homes upstream were dry.

“When it does exceed its containment, it’s devastating,” Megargle said.

A homeowner’s dilemma

In November, the Blaine County commissioners heard from one neighbor in Gimlet whose home was hit hard by the flooding.

The homeowner, James Daverman, has proposed building a 1,773-foot levee on the west bank of the Big Wood near Gimlet Road and Gimlet Lane. That would protect his home, which was built in 1995, and two other adjacent properties from future flooding. It’s one of the largest flood-control projects to be proposed to the county in years.

The proposal drew objections from other neighbors and conservation groups such as Trout Unlimited.

The commissioners have not yet made a decision on that project, but it elicited debate among them.

Commissioner Angenie McCleary wanted to deny it, while Commissioner Jacob Greenberg expressed a desire to allow homeowners to protect their property. The county, after all, approved the home in the first place. Commissioner Larry Schoen said he was concerned about setting a precedent.

In opposing the project, Alan Richardson, president of Trout Unlimited’s Hemingway Chapter, wrote to the county commissioners, and argued that the levee proposal embodies exactly what’s wrong with the Big Wood.

“The Big Wood River fishing pictures of Ernest Hemingway, Averell Harriman, Dwight Eisenhower, and so many other cultural, political and business leaders of the nation testify to the importance of the river to the quality of life, economy and welfare of the entire valley,” Richardson wrote. “Unfortunately, we have been losing much of the quality of the river over the last decades due to rapid property development along the river, with inadequate concern for long-term effects.”

Daverman dismissed those concerns during the hearing.

“This has not been the valley of Hemingway, or Harriman, or even Warren Miller for a long time,” Daverman told the commissioners. “And this is not a blue-ribbon trout stream. We have to acknowledge that government-permitted development has occurred up and down the river for years. It’s not going back to the way it was in 1920.”

A rush in homebuilding

From 1940 to 1969, only 26 homes were built along the Big Wood River between North Fork and the Bullion Street bridge in Hailey, according to the Mountain Express analysis. Most of the homes were in Ketchum or Hailey.

That includes Hemingway’s iconic home in north Ketchum, which was constructed in 1950. He purchased it in 1959.

The Mountain Express included only the homes that are immediately adjacent to the river banks, or with property lines extending to the riverbanks.

The homebuilding pace started to accelerate in 1970. In that decade, 53 riverfront homes were built along that stretch. North valley subdivisions started to build out.

The pace grew quicker in the 1980s, when 72 homes were built. It reached its peak in the 1990s, when 83 homes were constructed.

It’s been declining slowly since then. From 2000 to 2009, 62 homes were built along the river in that stretch. From 2010 to 2016, 12 homes were built, according to the analysis. The newest home was built along the river north of Ketchum in 2016.

Add that up, and 75 percent of the homes that sit alongside the Big Wood River in that stretch today have been constructed since 1980.

Gimlet and Della View are also newer subdivisions.

In Gimlet and on Broadway Run, 50 homes sit adjacent to the river. Several of those properties experienced flooding on June 2, about a month after the flooding began, according to an aerial photo maintained in Blaine County’s mapping database. Forty-five of those homes have been constructed since 1980.

In Della View, about 50 homes were taking on water on June 2, according to the aerial photo. Forty-three of those homes have been constructed since 1980, including 32 built since 1990.

Development and fish

Between 1988 and 1990, an Idaho Fish and Game research scientist named Russ Thurow wrote a series of reports about the health of the Big Wood River’s trout fishery.

Thurow’s research still holds up, Megargle said.

“That one is kind of like the Bible,” Megargle said. “The messages in it are true today.”

Thurow’s research examined the effects on fish populations of angler regulations, irrigation diversions, habitat loss and manmade alterations.

While at that time the trout were on par with the Henry’s Fork of the Snake River, Silver Creek, or the South Fork of the Boise River, Thurow expressed concerns about the loss of fish habitat.

Fish love cover like woody debris, as well as scour pools, steep riffles, rapids or plunge pools, Thurow wrote. They hate riprapped sections of the river, or areas with no cover.

Thurow determined that areas with cover like woody debris could support fish populations that were eight to 10 times higher than areas with riprapped banks or that lacked cover.

“As a consequence of habitat alterations, fish populations in affected stream reaches declined,” Thurow wrote. “Although several factors, including angler harvest and irrigation withdrawal affect its fish population, the most critical factor limiting trout population in the Big Wood River appears to be the amount and quality of fish habitat.”

In 1988, the fishery was declining, but Thurow expressed optimism that it could recover with habitat restoration and limits to stream-channel alterations.

“While it may be a shadow of its former fishery, the Big Wood River still maintains a viable wild rainbow trout population,” he wrote. “The future of fish populations in the Big Wood River will be dependent on our ability to 1) halt the continued, insidious loss of habitat, and 2) restore degraded areas. These tasks can be accomplished with acquisition of empirical data, public education and enactment of legislation.”

Megargle said the work that Thurow advocated continues today, as do debates over the size and severity of human impacts on fish.

Megargle added that fish density and habitat are not the only factors that influence the fishery’s health. He includes discharge, which results from snowmelt, and the amount of water that is left in the river for fish.

“Sometimes it’s hard to tease out what the human impacts are,” he said.

He said laws, resource management practices, restoration efforts and community values will determine the river’s future health.

“People love the Wood River Valley because of the Big Wood River,” he said. “We can love something to death.”

Megargle cited an increase in population in the Wood River Valley and more home development as two sources of pressure on the river system.

“I wish we could go back, but we can’t,” he said. “These are the attractive components of a tax base. The challenge here is not to move any further down the development road.”

Megargle said Fish and Game offers technical advice to local governments, including Blaine County, on impacts to the fishery.

“I would applaud Blaine County for being extremely interested in what those impacts are,” he said. “I have a positive outlook for the Big Wood River.”

After severe flooding in 2006, Megargle said, he started walking the Big Wood from Bellevue heading north. He was amazed by the new woody debris that had accumulated along the river. But before he got halfway up, property owners were taking chainsaws to the logs and removing them.

He understands the desire to protect property.

“If I owned that home, I would probably be thinking the same,” he said. “The easy fix is to armor a shoreline, pour a ton of riprap. It tends to deflect the problem downstream. Bit by bit, you start moving to a channelized system.”

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