From The Denver Post (Electa Draper:)

Colorado creeks changed lives, cities and landscapes during five days in September, but no transformation was greater than in the creeks themselves.

Dozens of streams charted new courses and claimed new territory — indifferent to the wreckage they left behind or carried along.

The St. Vrain abandoned its channel in at least 10 places between its headwaters above Lyons and its confluence with the South Platte River. Wherever the streambed was too small or too clogged, the rain-swollen creek jumped its banks or tore at them, leaving behind raw, chaotic landscapes.

“We have a new river,” said Sean Cronin, director of the St. Vrain and Left Hand Water Conservancy District. “We’re just now out of initial emergency response and looking at long-term recovery.”

Similar stories of the September floods can be read in each tributary of the South Platte, from Fort Collins to Boulder — the St. Vrain, Big Thompson, Little Thompson, James, Boulder, Fourmile creeks and others.

“Many channels are devastated. I would be hard-pressed to pick the worst loser,” said Deputy State Engineer Scott Cuthbertson with the Colorado Division of Water Resources.

And within reach of each river or stream, people in 14 counties who live, work and govern in these nearly unrecognizable basins are grappling with questions: Who is going to put the stream back where it was? Who is going to pay for it, and how many millions will it cost?

“Who determines the post-flood channel?” was a question even Colorado Water Conservation Board chairman Alan Hamel asked during an all-day meeting Oct. 21 on flood recovery.

“Where the river ends up needs to be a discussion by local communities,” responded river channel expert Chris Sturm, who heads up the Stream Team, a group of consulting experts from the state, Federal Emergency Management Agency and the U.S. Army Corps of Engineers.

“The state will help figure out who could help and where to find money, but we don’t prioritize,” Sturm said.

Yet, he said, when the team has met with local leaders in basin after basin, they seemed to expect the team to have regulatory authority over the streams and their course.

“Maybe they were a little disappointed we weren’t telling them where to put the rivers,” Sturm said.

Who is responsible?

The St. Vrains — north, south and middle forks — converge at the mouth of a canyon near Lyons, and then flow as one St. Vrain a little more than 32 miles through Hygiene and Longmont, under and past Interstate 25, to the South Platte River.

Together, the St. Vrain, and the Left Hand and Boulder creeks that join it, drain the mountains and foothills north and west of Longmont and Boulder.

In the flood, the St. Vrain channel migrated a few yards in some places and a few hundred yards in others. It chewed up highways and county roads and clawed at dirt banks that had held up homes and yards and turned them into towering, sheer and muddy cliffs.

The river destroyed or left high and dry most diversion structures for watering agricultural fields and serving drinking water. It disrupted all utilities in its corridor. Longmont lost four of five water supply lines. Lyons lost all its core infrastructure.

In one day, the flood rendered Longmont’s St. Vrain riverside trail — 20 years in the making — into a path without a river. The St. Vrain just took a new course.

Everywhere in the St. Vrain basin, from Button Rock Dam in the mountains west of Lyons to the city of Longmont, there is the same smell of freshly churned earth, pulverized rock, uprooted trees stripped clean as toothpicks, decomposing vegetation, brackish water, rusting metal and more decay.

“The question is, who is responsible for cleaning this up?” Cuth-bertson said.

Unlike after Hurricane Katrina, the Army Corps of Engineers will not reconstruct Colorado’s unique patchwork of now-fractured water infrastructure. The system was mostly built by private landowners, farmers, ditch companies, water districts, towns and cities. And they will be the ones to rebuild it, Cuthbertson and other state and federal authorities say.

“Everywhere I’ve been,” said Longmont Public Works and Natural Resources Director Dale Rademacher, “people have asked me, ‘When are they going to come fix it?’ They? There is no ‘they.’ No cavalry is coming to make the decisions. It’s us.”

On private property, it’s up to the owners to reclaim what land they can from the creek. They might be working near highway crews, and even National Guard units, reconstructing collapsed roadways.

“Everyone thinks (FEMA) is going to fix everything, as if we have the equipment to do anything,” FEMA Public Assistance expert Chris Thomas said.

FEMA doesn’t put rivers back in “their places.” It provides money to save lives and to give shelter to displaced individuals. It pays to remove flood debris and reduce immediate flood risks. It reimburses local governments for about 75 percent of the costs to repair flood-damaged infrastructure.

“But no one agency is going to come in and pay for everything,” Sturm said. And the puzzle of river restoration, he said, must be solved watershed by watershed.

Fluid, unyielding

Water’s fascination is that, while it’s seemingly fluid and yielding, it carries tremendous force, said Colorado State University geology professor Ellen Wohl . Water in motion is incredibly destructive on its own, but when it picks up cobbles, boulders, wood, cars, houses and other debris, that’s coarse-grained sandpaper on nature’s scale.

When the floodwaters receded, mile after mile of St. Vrain riverbed was left a broad, irregular, mostly waterless plain with mounds of sand, sediment and gravel braided with piles of gray rock and debris.

But that’s the short-term human perspective. Before Colorado was settled, its narrow canyons were river channel from wall to wall. Humans added roads and buildings in these tight spots and confined the channel. In one week in September, the stranglehold of asphalt, concrete and riprap on the St. Vrain was broken.

The river, from an ecosystem perspective, was as creative as it was destructive — new beds and paths, new aquatic life habitat in new pools and riffles and runs.

“No question, it was a disaster for people,” Wohl said, “but floods are actually good for the health of the rivers. They are dynamic systems. We try to make them less so. We create bland rivers.”

One can see, she said, geological evidence of how the rivers have migrated back and forth in the canyons over time.

“What we will wrestle with now is to what degree does the new river need to be embraced and to what degree does that (harm) our economy and way of life,” Rademacher said. “In most places, it’s probably just too costly to embrace the new river.”

Stream Team members say there might still be opportunities for communities and governments to plan together to mitigate future flood risks by leaving more open space around rivers in places where roads don’t dictate the channel. It could be a chance, they said, to reconstruct channels that would maximize the state’s typically low year-round stream flows to better serve aquatic life and recreation.

In many respects, Colorado streams are crowded places. The streambed is part of the private property of individual landowners. Yet stream flow and use is under the administration of the Colorado Division of Water Resources. And any dredging or filling of a stream below the normal high-water line requires a 404 permit from the U.S. Army Corps of Engineers under the Clean Water Act.

And by Colorado statutes, owners of rights to use water also have rights of access to streams over or through others’ private properties to locate their water-diversion structures, Cuthbertson said.

Streambed owners run the gamut from cities such as Boulder and Longmont to individual homeowners and resort operators, and from a small ditch system with a few hobby farmers on a couple hundred acres to big water districts.

“Right now we’re trying to figure out how to work together to restore irrigation and municipal water supplies, get the right voices at the table and keep nimble enough to work with federal agencies,” said David Bell, Boulder County’s manager of agricultural resources.

Where there is a decision to rebuild ruined homes along river channels and floodplains, residents must meet federal standards to remain eligible for the National Flood Insurance Program under FEMA.

Millions in damage

At Lyons, in just one example of challenges ahead, the St. Vrain once flowed under the McConnell Drive Bridge at Colorado 66, on the east side of town. Now there are a few stagnant mud puddles around the bridge instead of a creek.

Not many yards to the west, where a trio of quiet ponds had served as tranquil scenery for the Lyons Valley Park subdivision, the river ripped through them, connecting the ponds as part of its new channel. In the process, it annihilated a section of road running to Lyons Middle/Senior High School.

Longmont, Lyons and Boulder County are working together to fix the intersection. “The plan is to get the river back under the bridge, rather than build a second bridge,” Rademacher said.

The city of Longmont estimates flood repairs and rebuilding will cost it a total of $148 million. Lyons, with a $1 million annual budget, has estimated $50 million in damages, Rademacher said. Lyons was without municipal water and sewer, provided by Longmont, until Oct. 26.

Two-thirds of Longmont’s water supply comes from the St. Vrain, and most of that from the reservoir at Button Rock Dam.

It was weeks before city officials could drive a four-wheel-drive truck on a rugged white-knuckle trail through Hall Ranch to assess damage to the dam. The usual reservoir access is gone — water crumbled almost half of County Road 80, the 5-mile dam access road from U.S. 36, which itself reopened only days ago.

The inlet where the North St. Vrain flows into the reservoir is choked with boulders. Logs float on the reservoir’s surface — once sparkling blue but now the color of chocolate milk.

Floodwaters rushed out of the reservoir at such speed and volume that the spillway at the side of the dam is scoured to bedrock, and its banks were undercut so fast that an inches-thick layer of plant-covered topsoil, held together by roots, hangs over the new cliffs like a dirt tablecloth.

“It’s hard to remember how it was,” Rademacher said. “It’s disorienting.”

The city, in a race with winter, has asked a contractor to rebuild CR 80 by Thanksgiving in a road bed that is now a jumble of giant boulders, multiple creek channels and crumpled pipelines.

“We have no ability to use St. Vrain water at all,” Rademacher said.

These are just a handful of the thousands of stories of a reckoning and recovery just beginning.

Along Boulder Creek’s recreational trails last week, joggers and bicyclists lamented path closures but said they understood the need for a larger plan.

“I don’t think you can rush things,” said runner Bill Spencer. “As much as we would like to have it all back the way it was, I don’t think they can rush it (channel restoration). This could all happen again.”

That’s why the Stream Team is asking for a comprehensive approach.

“If you could rebuild it all over again, would you do it the same way?” Sturm asks. “It depends. We are advocating for master planning (in each watershed over four to 18 months). Fixes are happening right now, but maybe they’re no good for those upstream or those downstream.”

The Colorado Water Conservation Board might not have regulatory authority, but it has opinions and money at the table.

On Oct. 21, the water board approved $40 million for emergency 30-year loans to irrigators and water providers that will be interest- free for three years — with the first payments due in four years.

The CWCB also recently approved emergency Water Supply Reserve Account grants for the South Platte Basin in the amount of $1.65 million for water infrastructure recovery.

“There’s still a little bit of shock,” Cuthbertson said. “People are trying to understand the recovery process.”

Electa Draper: 303-954-1276, edraper@denverpost.com or twitter.com/electadraper

The September 2013 flood event — across a total of 24 counties — took nine lives, damaged 26,000 homes, destroyed more than 1,800 homes, damaged 765 businesses, destroyed 203 businesses, damaged or destroyed almost 500 miles of road, triggered inspections of 207 dams, caused nine small dams to fail, damaged or destroyed more than 160 water-diversion structures, damaged a roughly estimated 32,000 acres of croplands and swept away $350,000 in stream-gauge equipment.

The reason why no one yet knows peak flood flows during the event is that the deluge destroyed the measuring equipment. The U.S. Geological Survey, U.S Department of Agriculture and others are surveying the high-water marks to indirectly measure the flows.

Stream flows are still above long-term averages.

“The river basin is still draining. We’re still not really done with the flood event,” State Deputy Engineer Scott Cuthbertson said at the end of October.

There likely have been larger historic flows on one stream or another, but September’s flash flooding affected almost every tributary of the South Platte River from Denver to Fort Collins. The geographical area involved, the amount of rain and its duration of up to five days, have led many to tentatively call the storm a 1,000-year event. But that doesn’t mean it couldn’t happen again next year.

SOURCE: The Colorado Water Conservation Board’s watershed and flood protection section, the Colorado Division of Water Resources and Colorado Office of Emergency Management.