How safe are Denver Water’s dams? – News on TAP

Dam safety team conducts annual inspections, manages upgrades and trains for emergencies to keep facilities secure.

Source: How safe are Denver Water’s dams? – News on TAP

#Colorado Springs responds to @EPA/CDPHE lawsuit

From The Pueblo Chieftain (Robert Boczkiewicz):

The city’s denial is its first response in court to a lawsuit that claims discharges of pollutants into Fountain Creek and other tributaries violate the laws. The discharges are from Colorado Springs’ stormwater system…

Colorado Springs asserted in Monday’s filing that it “has at all times been in compliance” with permits issued by the state agency to govern the discharges and the stormwater system.

The city contends it should not be subjected to court orders or monetary penalties that the environmental agencies want a judge to impose.

Colorado Springs also contends that allegations in the lawsuit misrepresent the facts of issues in dispute.

Colorado Springs with the Front Range in background. Photo credit Wikipedia.
Colorado Springs with the Front Range in background. Photo credit Wikipedia.

#OrovilleDam: How much rain will fall on the Feather River watershed? Will the emergency channel lining hold?

Well it’s going to rain like hell tomorrow over the Feather River watershed.

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And California DWR has been lining the channels and the headwall cuts below the emergency spillway.

Oroville dam site emergency spillway repairs February 17, 2017 via CA DWR.
Oroville dam site emergency spillway repairs February 17, 2017 via CA DWR.

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And working on the Feather River below the spillway outfall.

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Finally, here’s a model of the extent of the possible flood:

Fountain Creek: Pueblo County and Lower Ark join @EPA/CDPHE lawsuit

From The Colorado Springs Gazette (Billie Stanton Anleu):

Pueblo County commissioners and the Lower Arkansas Valley Water Conservancy District can intervene in the suit, U.S. District Judge Richard P. Matsch ruled Thursday.

A year ago, Pueblo County commissioners signed off on an intergovernmental stormwater agreement with Colorado Springs, ensuring that the city will spend $460 million over 20 years to provide 71 stormwater projects aimed at minimizing Fountain Creek’s effects on downstream communities.

The creek flows downstream carrying excess sedimentation, E. coli contamination and other pollution, claims the Lower Ark, which represents the largely agricultural areas of Bent, Crowley, Otero, Prowers and Pueblo counties.

County officials have echoed those concerns.

And the EPA, after conducting audits in 2013 and 2015 of the city’s stormwater system, found that the creek and its tributaries were eroded and widened, their waters combining with surface runoff to create excessive sedimentation and substandard water quality.

Federal officials upbraided the city for not demanding enough infrastructure from developers and for not maintaining the culverts and creeks snaking through the city.

The lawsuit, filed by the U.S. Department of Justice on the EPA’s behalf, and by the Colorado Department of Public Health and Environment, is a serious concern for Mayor John Suthers, who has made the city’s long-neglected stormwater infrastructure a top priority.

In addition to the agreement with Pueblo County, he has more than doubled the stormwater division’s staff, added a new manager and overseen the Nov. 2 release of an inch-thick Stormwater Program Implementation Plan.

The EPA and state filed suit one week later, on Nov. 9.

From The Pueblo Chieftain (Anthony A. Mestas):

Pueblo County was granted a motion Thursday that allows the county to join in a federal/state lawsuit against the city of Colorado Springs.

The Lower Arkansas Valley Water Conservancy District also was allowed to join the case as an intervenor to protect the district’s interest during the litigation…

Pueblo County filed the motion to intervene last week. The lawsuit was filed Nov. 9 in U.S. District Court in Denver by the Environmental Protection Agency and the Colorado Department of Public Health and Environment against Colorado Springs.

The Lower Ark district filed the same motion in November.

The lawsuit claims there is harm caused by discharges of pollutants down Fountain Creek into Pueblo and east to the Arkansas River’s other tributaries.

It also claims the city of Colorado Springs made numerous violations of their Municipal Separate Storm Sewer System permit issued by the state.

Alleged violations by Colorado Springs include the failure to adequately fund its stormwater management program, to properly maintain its stormwater facilities and to reduce the discharge of pollutants to the maximum extent practicable.

Hart and fellow Commissioners Sal Pace and Garrison Ortiz have said they cherish the relationship the county has developed with Colorado Springs through negotiations over the Southern Delivery System’s 1041 permit agreement and hope this will not do anything to damage it.

The Fountain Creek Watershed is located along the central front range of Colorado. It is a 927-square mile watershed that drains south into the Arkansas River at Pueblo. The watershed is bordered by the Palmer Divide to the north, Pikes Peak to the west, and a minor divide 20 miles east of Colorado Springs. Map via the Fountain Creek Watershed Flood Control and Greenway District.
The Fountain Creek Watershed is located along the central front range of Colorado. It is a 927-square mile watershed that drains south into the Arkansas River at Pueblo. The watershed is bordered by the Palmer Divide to the north, Pikes Peak to the west, and a minor divide 20 miles east of Colorado Springs. Map via the Fountain Creek Watershed Flood Control and Greenway District.

Big-Picture Questions Raised by the Oroville Dam Emergency — Water Deeply

Water from the Oroville Dam auxiliary spillway has eroded the roadway just below the spillway. Photo courtesty of Kelly M. Grow/ California Department of Water Resources.
Water from the Oroville Dam auxiliary spillway has eroded the roadway just below the spillway. Photo courtesty of Kelly M. Grow/ California Department of Water Resources via @circleofblue.

From Water Deeply (Laura Feinstein, Peter Gleick):

Let’s not let a good crisis go to waste: Here are six important conversations that need to happen in the aftermath of problems at Oroville Dam in Northern California.

A critical question is whether the main spillway will be serviceable for the remainder of the winter. Dam managers must continue to release water down the damaged main spillway to maintain flood space behind the dam for coming storms and spring snowmelt. Bill Croyle, acting director of DWR, told the Sacramento Bee this past Sunday that his agency is not seeing further erosion of the main spillway at current flow levels of 100,000 cubic feet per second (cfs). Managers also shut down the turbines at the base of the dam that normally release up to 15,000 cfs because of downstream obstructions.

If another storm sends water into Oroville Lake faster than it can be released via the turbines and main spillway, then water could again over flow the concrete wall that forms the top of the emergency spillway. If the hillside beneath erodes further, this wall could collapse or be undermined, sending massive amounts of water downstream causing damaging, life-threatening floods.

Sacramento Bee has a concise recap of events here.

Can We Prevent These Types of Dam Crises in the Future?

It’s well-documented that the United States has chronically underfunded dams, levees, drinking water and wastewater infrastructure for years. The Association of State Dam Safety Officials estimates the cost of known needed repairs for the country’s 2,000 deficient, high-hazard dams at $21 billion. Drinking water, wastewater, waterways, ports and levees need repairs too. The American Society of Civil Engineers in a 2013 report put the unmet funding needs of our water infrastructure at $187 billion by 2020 (calculated in 2010 dollars).

Had the emergency spillway been lined with concrete, as was recommended in a motion filed by Friends of River, Sierra Club and South Yuba River Citizens League in 2005, it might have prevented the erosion that occurred this past weekend. In hindsight, it’s easy to see that this would have been a worthwhile investment compared to the cost of repairs, mass evacuations, and environmental impacts.

But the Oroville spillway crisis reveals another important question we haven’t been asking about our underfunded infrastructure. That is: How much money do we need to budget for upgrades that are becoming necessary as engineering standards improve and climate change imposes greater pressures on the system? We may be on the hook for even more money than we realize.

Where Are We Going to Get the Money to Repair the Spillways?

Preliminary estimates to repair just the main spillway are in the range of $100m-$200m, according to Bill Croyle at DWR. The State Water Contractors that get their water from the State Water Project will likely have to pay for at least part of the repairs, and they will pass the costs on to their ratepayers. Three more things to note.

First, these expenses are likely to cause increases in costs for ratepayers, some of whom are already struggling to pay their water bill. Second, we should expect a vigorous debate as to who else should help foot the bill. Should residents of the floodplain pay for a portion of the repairs, since they benefit from flood control? Should all California taxpayers chip in via allocations from the General Fund or Proposition 1 Bond monies? Third, these types of public works projects cannot be incentivized with tax deductions to private companies looking to build profitable projects, as the Trump administration has proposed.

Are We Going to See More Water Emergencies as the Climate Changes?

Scientific models project, and observational data corroborates, that California’s climate is becoming more variable, with hotter, longer droughts and bigger precipitation events. The state’s water system was designed for a climate we no longer have. More extreme events are going to test the limits of our infrastructure and reveal new weaknesses in the system.

What Does This Mean for the Feather River Ecosystem?

In general, storms are good for rivers. California’s river ecosystems are adapted for big pulses of water in the winter. But the Feather River, where Oroville Dam is located, has been heavily altered by people, so these storms play out differently than they did before the river was dammed and leveed.

Feather River Hatchery spawns about 30 percent of the fall-run Chinook salmon in the state, as well as large numbers of spring-run Chinook and steelhead trout. Spring-run Chinook and Central Valley steelhead trout are listed as threatened under the Endangered Species Act; fall-run Chinook are still an important species for commercial fishing. Hatchery staff relocated five million juvenile salmon to a nearby facility, and have rigged a system to bring in municipal water to support the 1 million steelhead still at the hatchery. If hatchery operations go awry, it could impact populations of these valuable species.

The Feather River itself is still an important spawning ground for natural salmon and steelhead. But levees mean the river is restricted to a narrow channel, where rapid flows scour out the nesting grounds. Meanwhile, influxes of sediment and debris are likely to damage spawning grounds in the short run.

The Oroville Dam and the levees downstream were built for the joint goals of water storage and flood prevention, but floods are healthy for both the river and the floodplain. Long term, California should be thinking about places where it can move levees and allow rivers to reconnect with their floodplains.

Looking Forward

Nobody wants to see people evacuated from their homes because of a potential natural disaster. The silver lining to a crisis is that it can generate political will to deal with unpleasant, chronic problems. The problems at Oroville Dam are linked to unresolved issues we have with funding our infrastructure, adapting to climate change and restoring natural ecosystems. Let’s move forward in ways that address the immediate emergency and the long-term problems.

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Meanwhile, here’s a report about US dam safety from Brett Walton and Circle of Blue:

The near-failure on Sunday evening of the auxiliary spillway at Oroville Dam and the ongoing emergency operations to contain flood waters in California’s second-largest reservoir and shore up its eroding outlet are a tale of caution for the nation’s aging dam fleet.

“I think it should give many people reason to step back and take a hard look at things, including California,” wrote Martin McCann, director of the National Performance of Dams Program at Stanford University, in an email to Circle of Blue.

The Oroville emergency is unfolding in a state with a dam safety program widely regarded as the nation’s strongest. McCann agreed that California’s efforts to prevent a partial collapse of Oroville’s auxiliary spillway should be a wakeup call for other states with less vigilant dam regulation. Alabama, for instance, has no state dam oversight at all.

Already the top spending state for dam safety, both in total dollars and inspectors per dam, California increased its program budget by six percent between 2014 and 2016, to $US 13.3 million. The Department of Water Resources’ Division of Safety of Dams has roughly one employee per 20 state-regulated dams. That is far greater than the national average of one employee per 200 dams, according to data from the Association of State Dam Safety Officials.

“California has had a strong dam safety program for many decades,” McCann said. “It’s well-funded, well-staffed, and they inspect regularly.”

Dam safety experts cite money as the most significant impediment to safer dams. Though California spends big on oversight, the cost of repairs has emerged as a factor in the Oroville emergency. Reporting from the Mercury News revealed that state and federal officials rejected an appeal from three environmental and civic groups in 2006 to line the auxiliary spillway with concrete. The groups were concerned that the topsoil on the hillside spillway would erode if it were ever used. February 11 was the first time that water flowed over the auxiliary spillway since the 770-ft-tall dam was completed in 1968. Use of the auxiliary spillway was necessary because of damage to the main spillway and inflows to the reservoir that nearly matched the flow of the Mississippi River at St. Louis. Officials had to evacuate as much water as quickly as possible.

Most of the more than 90,500 dams in the U.S. Army Corps’ national dam database, however, are not behemoths like Oroville. Most instead resemble Twenty-one Mile Dam, a 47-foot-tall earthen structure in Elko County, Nevada. Owned by Winecup Gamble Ranch, a 948,000-acre livestock operation, the dam burst on February 9 during heavy rain. Flood waters released by the dam chewed through 200 yards of Highway 233, which remains closed.

Two-thirds of U.S. dams are privately owned and often owners do not have funds for maintenance or repair, according to Lori Spragens, executive director of the Association of State Dam Safety Officials. Most U.S. dams are more than 50 years old and an unknown number are not built to current safety standards. The association estimates that $US 18.7 billion is needed to repair high-hazard, state-regulated dams. High-hazard dams could kill people if they failed…

The pressure on Oroville will not soon let up. The watershed above the dam is expected to get as much as eight inches of precipitation through February 21. Then in the spring, the massive snowpack, measuring twice the historical average in some spots, will melt. The California Nevada River Forecast Center estimates that water flows in the Feather River, which drains into Oroville, will peak on April 29.

All of which has state officials on constant alert. “We want to complete assessments, do corrective measures on the emergency spillway, and get it ready for potential future use here in the coming weeks or months,” said Bill Croyle, acting director of California Department of Water Resources.

Erosion below the emergency spillway at the Oroville Dam site, via Hamodia
Erosion below the emergency spillway at the Oroville Dam site, via Hamodia

Fountain Creek: Pueblo County commissioners approve county joining @EPA, CDPHE lawsuit

Fountain Creek erosion via The Pueblo Chieftain
Fountain Creek erosion via The Pueblo Chieftain

From The Pueblo Chieftain (Anthony A. Mestas):

The Pueblo County commissioners on Wednesday asked staff to file a motion to intervene in a lawsuit filed Nov. 9 in U.S. District Court in Denver by the Environmental Protection Agency and the Colorado Department of Public Health and Environment against Colorado Springs.

Pueblo County wants to join the case to protect its interest during the litigation.

“We did it primarily to make sure we have a seat at the table,” said Pueblo County Commission Chairman Terry Hart.

“It’s one of those issues that whenever any kind of conversation is going on that concerns Fountain Creek or the water volume or quality that’s in the creek, we feel it affects the citizens in our community.”

[…]

By intervening in the lawsuit Pueblo County hopes to:

Support the EPA and CDPHE in its regulatory mission.

Ensure that stormwater control infrastructure within Colorado Springs is properly operated and maintained.

Ensure that there are no conflicts or inconsistencies between the stormwater intergovernmental agreement recently entered by the county and Colorado Springs and any remedy, judgment or settlement entered in this case.

Require Colorado Springs to become, and then remain, compliant with the Clean Water Act, the Colorado Water Quality Control Act, stormwater regulations and the conditions of Colorado Springs’ MS4 permit, and protect against future violations.

Work with Colorado Springs to develop, implement and enforce its’ Stormwater Management Program as required by the MS4 permit.

Prohibit Colorado Springs from discharging stormwater that is not in compliance with its MS4 permit or its SMP.

#Colorado’s dam safety examined

Horsetooth Reservoir
Horsetooth Reservoir

From The Fort Collins Coloradoan (Jacy Marmaduke):

The good news: All of Larimer County’s biggest dams, including the dams at Horsetooth Reservoir, have emergency action plans designed to prepare authorities for emergencies like what happened in California this weekend.

And the bad: A small percentage of Colorado’s higher-hazard dams don’t have emergency plans. Failure could put human lives, environment and property at risk.

It’s a problem highlighted nationwide this week after the Oroville Dam, located about 75 miles north of Sacramento, suffered a potential failure of its emergency spillway. While the dam itself remained intact, erosion damage to the spillway raised the possibility of the structure failing and unleashing an uncontrolled torrent of water.

This situation is unlikely to occur at any of the Horsetooth Reservoir dams, according to officials from the Bureau of Reclamation and Northern Water. That’s partially because the structures underwent an $85 million renovation in the early 2000s. The modernization project included stripping the dams’ faces and adding a roughly 16-foot-thick filter of sand and gravel. Each of the dams was also bolstered for extra strength.

The lower risk here is also a question of magnitude, said Northern Water spokesman Brian Werner, who noted that the amount of water released through the Oroville Dam in 24 hours is more than Horsetooth Reservoir could hold at full capacity.

Perhaps most importantly, Horsetooth Reservoir’s relationship to its dams and water sources is different from Lake Oroville’s relationship with the Oroville Dam and the Feather River, which the dam impounds to form the lake. No river runs into Horsetooth Reservoir; gravity transports water there from other reservoirs in the Colorado-Big Thompson Project.

The Bureau of Reclamation in June 2016 finished a comprehensive review of Horsetooth Reservoir’s dams, which include the Horsetooth, Dixon Canyon, Soldier Canyon and Spring Canyon dams. All passed inspection.

Larimer County is home to 136 of Colorado’s 1,737 dams, according to 2013 data from the National Inventory of Dams. Twelve of those dams are very large…

Each of Larimer County’s high-volume dams received a satisfactory inspection rating at its most recent inspection, and none is used for flood control. All have emergency action plans, which include critical information like emergency contacts, details about the dam and an inundation map that shows where flooding will occur at different water levels…

Of Colorado’s 1,737 dams, about 25 percent, or 425, are considered “high hazard,” meaning one or more people are likely to die if the dam fails. About 96 percent of those dams have emergency action plans, significantly higher than the national rate of 69 percent.

An additional 19 percent of Colorado dams are considered a “significant hazard,” which means their failure would result in possible loss of human life and likely significant property or environmental destruction. About 92 percent of those dams have emergency action plans.

Inspection of Colorado dams falls to two agencies. The state’s dam safety division evaluates dams owned locally or by private and state agencies, and the Bureau of Reclamation monitors federally owned dams.