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Is the Oreville Dam Going to Fail Again?

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Potential failure during 2017 rainstorm

Oroville Dam crisis
Oroville dam spillway 2017-02-11.jpg

View of Oroville Dam's main spillway (center) and emergency spillway (tiptop), Feb eleven, 2017. The big gully to the correct of the main spillway was caused by water flowing through its broken and damaged concrete surface.
Appointment February 2017
Location Oroville Dam
Coordinates 39°32′33″N 121°29′31″W  /  39.5426°Northward 121.4920°W  / 39.5426; -121.4920 Coordinates: 39°32′33″N 121°29′31″W  /  39.5426°Northward 121.4920°W  / 39.5426; -121.4920
Cause High rainfall

In Feb 2017, heavy rainfall damaged Oroville Dam'southward main and emergency spillways, prompting the evacuation of more than 180,000 people living downstream forth the Plumage River and the relocation of a fish hatchery.

Heavy rainfall during the 2017 California floods damaged the primary spillway on February 7, so the California Section of Water Resources stopped the spillway period to assess the damage and contemplate its side by side steps. The pelting somewhen raised the lake level until it flowed over the emergency spillway, even after the damaged principal spillway was reopened. Every bit h2o flowed over the emergency spillway, headward erosion threatened to undermine and collapse the concrete weir, which could have sent a thirty-foot (ten one thousand) wall of water into the Feather River beneath and flooded communities downstream. No collapse occurred, but the h2o further damaged the main spillway and eroded the blank slope of the emergency spillway.

Groundwork [edit]

Oroville Dam, an important part of the California State Water Project, is an earthen embankment dam on the Plume River, east of the urban center of Oroville in Northern California. The dam is used for flood command, water storage, hydroelectric power generation, and h2o quality improvement in the Sacramento–San Joaquin River Delta.[one] : A1, A5 Completed in 1968, information technology is the tallest dam in the United States, at 770 feet (230 m).[two] [1] : A1, A5–A6 Information technology impounds Lake Oroville, the second largest human-made lake in the state of California, capable of storing more than than three.v meg acre-feet (four.three billion cubic meters).[3] [four] The adjacent Edward Hyatt Powerplant has 6 power-generating turbines with a total installed chapters of 819 megawatts (MW) of electricity.[five]

The Oroville dam before the crisis, with main spillway center and overflow spillway on the left

The Oroville dam before the crunch, with chief spillway eye and overflow spillway immediately to the left, above vegetation

For flood control purposes, some space in Oroville Reservoir has to be kept dry to capture floodwaters, a do that has acquired controversy at other dams of California over the amounts of water wasted.[6] Dam operators were required to belch water based on charts contained in the Oroville Dam Reservoir Regulation Manual, a flood-command transmission developed by the U.Southward. Ground forces Corps of Engineers.[7] [viii] : vi–9 At the time of the incident, the Oroville Dam Reservoir Regulation Transmission had terminal been updated in 1970 and the belch charts were based on climatological information and runoff projections that did not account for climate change or pregnant floods in 1986 and 1997. In the immediate aftermath of the incident, it was not clear if the outdated manual was a significant cistron in the February 2017 crisis.[seven] [9] The Final Study of the Independent Review Board, released xi months subsequently the crunch, did not cite the outdated manual equally a meaning factor.[10]

The dam complex was designed with four routes for h2o to laissez passer from Lake Oroville:

  1. Through the hydro-electric generators, which have a combined maximum menstruation rate of xvi,950 cu ft/due south (480 g3/due south).[5]
  2. Through a river outlet (besides known as the bypass valve) that has a capacity of five,400 cu ft/south (150 thou3/s).[i] : A5–A6
  3. Through the main (service) spillway located on the northwest abutment of the dam, which is used to control the height of the reservoir by quickly releasing large amounts of excess water downwardly a three,050 ft (930 m) concrete-lined channel that extends to the river below. Water flow onto the primary spillway is controlled by eight radial (Tainter) gates that have a combined maximum discharge capacity of 270,000 cu ft/s (vii,600 chiliad3/southward) when the lake elevation is 905 feet. Since the sill top of the spillway is 813.6 ft (248.0 m), it can simply be used at lake elevations in a higher place that level.[1] : A5–A6 [11]
  4. Over the meridian of an emergency spillway, consisting of a 1,730-foot (530 m) long, 30-foot (nine.1 m) high concrete weir beside the main spillway and the side by side earthen gradient of the abutment. Once the lake reaches an elevation of 901 ft (275 k) above hateful bounding main level—21 anxiety (6 grand) beneath the acme of the main dam construction—water flows, uncontrolled, over the weir and down the earthen slope until it reaches the river below.[12] [1] : A5–A6

In 2005, the dam underwent re-licensing by the Federal Energy Regulatory Committee, during which three ecology advocacy groups filed a motility with the FERC raising concerns about utilise of the emergency spillway.[2] [13] The environmental advocacy groups stated a 2002 technical memorandum past the Yuba Canton Water Bureau that noted that significant erosion of the hillside would occur if the emergency spillway is used, which could cause pregnant downstream harm and impair operation of the Edward Hyatt Powerplant.[8] : 13 The groups urged the FERC to condition renewal of the Oroville Dam's license on the lining of the gradient of the emergency spillway with concrete and to update the Oroville Dam Reservoir Regulation Manual.[13] [2] [8] : 24–28

According to FERC engineering guidelines, "Emergency spillways may exist used to obtain a high degree of hydrologic condom with minimal additional cost. Because of their exceptional utilise it is acceptable for them to sustain significant damage when used and they may exist designed with lower structural standards than used for auxiliary spillways."[8] : eighteen–nineteen The FERC determined that the emergency spillway structure was compliant with its engineering standards and that the erosion concerns raised by the environmental advocacy groups were overblown.[13] The committee too determined that the emergency spillway could handle 300,000 cu ft/s (8,500 mthree/s) of discharge and renewed the dam'south license without requiring the concrete lining of the emergency spillway, estimated to toll over $100 million.[13] [ii] A 2018 study by the Clan of State Dam Safety Officials discovered that the committee relied on original geology reports from the 1960s, stating that the hillside below the emergency spillway was bedrock; information technology was really weathered rock subject area to deep erosion if the spillway were to be put into use.[14]

Fractional view of the emergency spillway (left) and the concrete structure containing the gates for the principal service spillway (right)

Prior to Feb 2017, the main spillway had been concluding inspected in Baronial 2016. During that inspection, the spillway was visually inspected without inspectors entering the spillway chute. Inspectors entered the spillway chute for inspections in 2014 and 2015 without finding any concerns. Cracks in the physical spillway chute were repaired in 2009 and 2013.[15]

Timeline of crisis [edit]

Timeline of Oroville Dam crunch, February 2017
Oroville Dam normal operations 2005: Upgrade proposal rejected 7 February 2017: Primary spillway fails
raw example of images beneath text
1. The lake level is controlled using the main spillway gate, which releases water downward the physical spillway to get to the river below.
two. The emergency spillway, which has a 30 ft (9 one thousand) high concrete wall at the top of a colina, is unused. 		Despite concerns that the emergency spillway is vulnerable to erosion, a $100 million request by environmentalists to upgrade information technology to a physical-lined auxiliary spillway is rejected by the federal regulators. Craters appear in the main spillway. To avert increasing the impairment to the spillway, water releases are slowed assuasive the lake to ascent.
OROVILLE DAM 1.svg OROVILLE DAM 2.svg OROVILLE DAM 3.svg
11 Feb 2017: Emergency spillway used thirteen February 2017: Repairs made Potential risks
Water flows over the emergency spillway causing erosion and damage. This is by design and prevents water going over the top of the main dam. Yet the basis erodes faster than expected. Rocks and physical (1) are placed under the emergency spillway weir to repair erosion damage (ii). The release of water into the main spillway is increased, to lower the lake in grooming for more rain. This erodes the side by side hillside considerably, generating a debris dam (3) that blocks the river and forces the closure of the hydroelectric plant. While the main 770 ft (230 m) dam is non threatened, if the erosion on either spillway reaches the top, it would crusade the weir or gate (respectively) to collapse, causing a large uncontrolled water release and life-threatening floods.
OROVILLE DAM 4.svg OROVILLE DAM 5.svg OROVILLE DAM 6.svg
version 3 – February 28, 2017 public domain OK to share and use

Main spillway damage [edit]

In early February 2017, loftier inflows to Lake Oroville acquired dam operators to get-go using the concrete main spillway to control the lake level.[16] Betwixt February six–10, 2017, 12.8 in (330 mm) of pelting roughshod on the Feather River Basin. Inflow of h2o into Lake Oroville rose from 30,000 cu ft/s (850 one thousandthree/south) on February 6 to over 130,000 cu ft/s (3,700 m3/south) at mid-day on February seven, earlier subsiding to near 75,000 cu ft/s (2,100 chiliad3/south) the following day.[17] Dam operators began increasing the menstruum downwards the main spillway to 54,500 cu ft/s (1,540 g3/s) on Feb 7 but before long noticed an unusual flow pattern.[17] The flow of water down the spillway was stopped for investigation, revealing a crater near halfway down the spillway where the concrete lining was eroded through and water was escaping the physical chute.[17] [18] The DWR consulted with FERC and other dam safety agencies about the upshot and prepared for the possibility of using the emergency spillway.[17]

During two exam flows down the spillway on February eight–9, the length of the crater increased from 250 ft (76 k) to 300 ft (91 k).[18] Meanwhile, the level of Lake Oroville was rising as inflow into Lake Oroville skyrocketed from nigh 130,000 cu ft/s (3,700 1000iii/south) on February seven to a peak of 190,435 cu ft/southward (5,395 yardthree/s) tardily on February ix.[17] The DWR was then confronted with two choices: use the primary spillway, knowing it would probable be further damaged, or allow Lake Oroville to rise until it overtopped the emergency spillway.[18]

March 2011

February seven, 2017

Feb 27, 2017

Harm to the main spillway began as a crater in the middle (center) and somewhen resulted in a carve up channel eroded to the side (correct). At left, the master spillway is shown in March 2011 while at its maximum discharge rate.

On Feb 9, the main spillway was reopened. DWR hoped that using the damaged spillway with a limited flow could drain the lake plenty to avert use of the emergency spillway, which would potentially damage powerlines servicing the hydroelectric plant.[nineteen] The following twenty-four hours, belch on the primary spillway was reduced from 65,000 cu ft/due south (1,800 m3/s) to 55,000 cu ft/s (1,600 mthree/due south), just this menses was non enough to prevent the lake from rising.[20] [21] [17] On February 11, the lake level reached 901 ft (275 thousand) in a higher place mean sea level and water began flowing—equally designed—over the concrete weir along the pinnacle of the emergency spillway, cascading onto the emergency spillway for the first time in the dam'due south history.[12]

Emergency spillway damage [edit]

H2o flowing into Oroville Dam'due south main spillway (bottom) and flood into the emergency spillway (top), February 11, 2017

As the lake level rose, measures were taken to gear up the emergency spillway for use. On February 10, 2017, workers began articulate-cutting trees on the hillside below the emergency spillway.[22]

Before long after viii:00 am on February eleven, 2017, the emergency spillway began conveying water for the first time since the dam'southward construction in 1968.[23] Because the spillway was a split construction from the dam, officials stated that there was no danger of the main embankment being breached, and evacuation of Oroville was non considered at that time, every bit officials stated that there was no threat to public safety. The uncontrolled menstruum over the weir topped out at 12,600 cu ft/s (360 m3/s).[24] [25]

Erosion at the base of the weir—which was expected—progressed much faster than anticipated.[17] The headward erosion of the emergency spillway threatened to undermine and collapse the physical weir, in which instance a 30-foot (9 1000) wall of water would be sent into the Feather River below and flood communities downstream.[12] Fearing a collapse, the Butte Canton Sheriff's Office issued an evacuation order of the Oroville area.[12] [17] To ease force per unit area on the emergency spillway and preclude a possible collapse of the weir, the DWR nigh doubled the discharge volume of the chief spillway from 55,000 cu ft/southward (1,600 1000three/southward) to 100,000 cu ft/s (two,800 m3/s).[17] Several hours later, water stopped flowing over the weir onto the emergency spillway and officials began assessing the state of the emergency spillway.[17]

Evacuation of the Feather River Basin [edit]

Aeriform view of spillways and erosion on February 12

On Feb 12, 2017, evacuation was ordered for those in low-lying areas along the Plume River Basin in Butte, Yuba and Sutter counties, because of an anticipated failure of the emergency spillway.[26] Specifically, erosion on the hillside was growing uphill toward the physical lip of the emergency spillway, leading to the fearfulness that information technology would collapse. A failure of the physical top of the spillway would let up to 30 feet (9 grand) vertical of Lake Oroville through the gap in an uncontrolled deluge.[27] The period over the primary spillway was increased to 100,000 cu ft/s (2,800 chiliad3/south) to try to dull the erosion of the emergency spillway.[28]

Past 9 p.one thousand. on the evening of February 12, the increased menses had successfully lowered the water level to below the emergency spillway elevation, causing the emergency spillway to stop overflowing. The stop in water menstruation allowed the erosion at that place to be hastily inspected and stabilized with boulders.[27] Engineers worried that the damage would exist transferred to the primary spillway, not merely making future repairs more expensive, but likewise that the damage to the primary spillway could grow uphill to the betoken that it endangered the primary spillway gates, leaving no safe manner to release water. The extent of such damage was unknown; it was expected to exist assessed on the morn of February 13.[27] On February 13 helicopters began to drop sandbags and large rocks in the area of the now-dry emergency spillway, in order to protect the base from erosion.[29] [xxx] By February 13, 188,000 people in the vicinity were reported evacuated.[31] Nigh 23,000 National Guardsmen were ordered to be ready for "immediate deployment if the dam spillway should fail" to help with evacuation and relief efforts.[29] On February 14, at 2:45PM local fourth dimension, the evacuation order in a higher place was reduced to an evacuation watch by emergency direction officials and the State of California Department of Water Resources, and people were allowed to return to the evacuated areas.[32]

  • Level of Lake Oroville, February 3–23

  • Chart of Lake Oroville arrival and outflow, Feb four–25

  • Emergency shoring of the emergency spillway with rock and physical (February 16)

  • Stone being loaded into bags for send by helicopter (upper right) to reinforce the emergency spillway (Feb 13)

  • Closeup view of emergency reinforcement (concrete over rocks) on emergency spillway (Feb 19)

  • Aerial view of erosion on the emergency spillway (February 16)

  • Senator Kamala Harris joins local officials in performing an aerial inspection of the dam (February 23)

  • Eroded soil and droppings blocking Feather River (February 27)

Downstream effects [edit]

Baby salmon being rounded up (left) from the murky waters at the Plume River Fish Hatchery, due to soil eroded at the spillway, and unloaded at the Thermalito Afterbay Complex (correct)

The immediate harm from the damage is limited to the area downstream of the alienation, eroding the hillside to form a canyon. However, a major danger is that the spillway can erode back up toward the gate because of beingness undercut by the h2o falling into the crater. Eventually, this would threaten the spillway gate, in close proximity to the bodily abutment of the dam.[20]

About 150,000 cubic yards (110,000 mthree)[33] of erosion droppings clogged the channel of the Feather River below the dam, preventing release of h2o from the hydroelectric establish, thus reducing the overall capacity of the dam to release water.[20] Debris was carried downstream and acquired harm to the Feather River Fish Hatchery due to high turbidity.[34] Land workers began evacuating fish and eggs from the hatchery in an try to mitigate the impairment and evacuated over ix meg fish downstream to a satellite hatchery adjacent to Thermalito Afterbay.[35] [36]

On Feb 27, the flow to the spillway was temporarily shut off, allowing crews to begin removing debris in the river in grooming to restart the power establish.[37] After the spillway was shut off, information technology appeared that headward erosion forth the spillway channel had mostly stabilized, reducing the immediate threat of a gate failure and uncontrolled water release.[38] The bedrock under the upper half of the spillway appears to be much stronger than the stone which was washed out under the midsection of the spillway. In addition, the force of the falling water had excavated the original crater into a deep plunge puddle which acts as a hydraulic cushion, dissipating much of the energy that otherwise might accept acquired additional damage to the spillway.[39]

Investigation [edit]

The Federal Energy Regulatory Commission (FERC) ordered the California Department of Water Resources (DWR) to assemble a team of five independent experts to appraise the dam and effect recommendations.[40] On February 17, 2017, the DWR commissioned an contained Board of Consultants (BOC) to investigate causes, review and comment on repairs to Oroville Dam.[41] Memoranda (reports) prepared by the BOC are posted at the DWR web site.[42] DWR besides assembled an Independent Forensic Team (IFT) to determine the cause of the spillways incident, including effects of operations, direction, structural blueprint and geological conditions, and the IFT published a nearly 600-folio report in January 2018.[10] [43] The DWR also requested full-time FERC staff to provide immediate oversight, review, and approval of repair plans that would make the dam safe for the 2017–18 inundation season.[43]

Department of Water Resource 2017–18 Operations Plan [edit]

The DWR prepared a Lake Oroville 2017/2018 Flood Command Season Operations Plan.[44]

Public hearings [edit]

On May 11, 2017, a hearing took identify. During the hearing, California Department of Water Resource came under criticism for ignoring warning signs in the spillway'southward designs. Butte Canton Supervisor also complained that DWR had broken promise with Oroville, as the canton had to spend $five.3 one thousand thousand annually for dam-related services, while getting no compensation from the state. Witnesses also stated that DWR did non take safe seriously.[45]

Repairs [edit]

The Oroville Dam principal spillway on August 5, 2018, during phase 2 repairs

The chief spillway was successfully reconstructed by Nov one, 2018.[46]

According to its 2017–18 operations programme, the DWR maintained Lake Oroville at a lower than normal level to reduce the possibility that the spillway would accept to be used the following winter.[47]

In a second phase of spillway repairs in 2018–19, temporary repairs on the master spillway done during Phase 1 were being torn out and replaced with steel-reinforced structural concrete.[48]

On April ii, 2019, due to heavy rainfall upstream, the DWR began releasing water over the newly reconstructed spillway at a charge per unit of 8,300 cu ft/s (240 m3/s).[49] Releases were increased to 25,000 cu ft/south (710 thousand3/s) on April 7 to test how the spillway performed in higher flows. They were decreased to 15,000 cu ft/south (420 one thousand3/due south) on April nine.

References [edit]

  1. ^ a b c d e "Oroville Facilities (FERC Project No. 2100)" (PDF). California Department of H2o Resources. January 2005. Retrieved February xiii, 2017.
  2. ^ a b c d Guerra, Christine (February 14, 2017). "The government was warned that the Oroville Dam emergency spillway was unsafe. It didn't mind". Washington Post . Retrieved February 23, 2017.
  3. ^ "Alphabetical List of California Dams (Over 40,000 acre feet)". Civil and Environmental Applied science. University of California Davis. Archived from the original on Feb five, 2012. Retrieved March 31, 2012.
  4. ^ Boxall, Bettina; McGreevy, Patrick (February 12, 2017). "Thanks to storm runoff, in that location's a lot of h2o over California's 2nd-largest reservoir". Los Angeles Times. ISSN 0458-3035. Retrieved September 10, 2017.
  5. ^ a b "Hyatt Powerplant". California Department of Water Resource. Archived from the original on April 7, 2012. Retrieved Feb 13, 2017.
  6. ^ "Largest California reservoirs releasing h2o for flood safety". sacbee . Retrieved February eighteen, 2017.
  7. ^ a b Sabalow, Ryan; Furillo, Andy (February 15, 2017). "Oroville Dam'south overflowing-control manual hasn't been updated for half a century". Sacraento Bee . Retrieved February 23, 2017.
  8. ^ a b c d Stork, Ronald; Eberhart, Allan; Rainey, Jason (October 17, 2005). "Motion to Arbitrate of Friends of the River, Sierra Club, Due south Yuba River Citizens League" (PDF). Archived (PDF) from the original on Feb xviii, 2017. Retrieved Feb 23, 2017.
  9. ^ "Oroville Dam Transmission Last Updated in 1970". U.Southward. News and World Study. Associated Press. February 16, 2017. Retrieved Feb 23, 2017.
  10. ^ a b Independent Forensic Team (January 5, 2018). "Independent Forensic Squad Report: Oroville Dam Spillway Incident" (PDF) . Retrieved June fourteen, 2018.
  11. ^ "Image: Inundation Control Outlet Rating Curve". reddit . Retrieved Nov thirteen, 2017.
  12. ^ a b c d Plumer, Brad (February thirteen, 2017). "The Crisis at Oroville Dam, Explained". Vox.
  13. ^ a b c d Rogers, Paul (February 12, 2017). "Oroville Dam: Feds and land officials ignored warnings 12 years ago". The Mercury News . Retrieved Feb 23, 2017.
  14. ^ https://damsafety.org/sites/default/files/files/Independent%20Forensic%20Team%20Report%20Final%2001-05-18.pdf pg53
  15. ^ Pritchard, Justin; Knickmeyer, Ellen (February 15, 2017). "Cracks may offer clues to California dam's troubles". Associated Press. Retrieved March ane, 2017.
  16. ^ Graff, Amy (February x, 2017). "Gaping hole in Oroville Dam spillway is growing, officials warn". SFGate . Retrieved February x, 2017.
  17. ^ a b c d e f g h i j "Lake Oroville Spillway Incident: Timeline of Major Events February 4–25" (PDF). California Section of Water Resources. February 27, 2017. Retrieved March 1, 2017.
  18. ^ a b c Kasler, Dale; Sabalow, Ryan; Reese, Phillip. "Crater in Oroville Dam spillway will continue to grow, officials warn, equally reservoir levels climb". Sacramento Bee. Retrieved Feb 9, 2017.
  19. ^ "Sacrificing California spillway may avoid emergency releases". Retrieved February 11, 2017.
  20. ^ a b c "Use of untested emergency spillway notwithstanding again a possibility at bedridden Oroville Dam". Sacramento Bee . Retrieved February 12, 2017.
  21. ^ CA DWR (February 10, 2017). "Lake Oroville Releases Slowed to Avert Erosion" (PDF). Archived from the original (PDF) on February 13, 2017. Retrieved February 12, 2017.
  22. ^ "In Historic Beginning, Lake Oroville Flows Over Dam's Emergency Spillway". KQED News. February eleven, 2017. Archived from the original on February ten, 2017. Retrieved February 11, 2017.
  23. ^ "The Latest: Emergency Spillway Use Likely at Oroville Dam". ABC News. Associated Press. February x, 2017. Retrieved February 10, 2017.
  24. ^ "Water flowing out of Lake Oroville emergency spillway". SF Gate. Feb 12, 2017. Retrieved February 12, 2017.
  25. ^ @CA_DWR (February 12, 2017). "Flows down the emergency spillway peaked last night at 1 a.k. at 12,600 cfs. Lake elevation levels are trending down.@CALFIRE_ButteCo" (Tweet) – via Twitter.
  26. ^ KCRA Staff (Feb thirteen, 2017). "Thousands from Yuba, Butte, Sutter counties evacuated". KCRA . Retrieved February 13, 2017.
  27. ^ a b c Reese, Phillip; Sabalow, Ryan (February 12, 2017). "Experts: Country left with few options while trying to avoid disaster at Oroville Dam". Sacramento Bee.
  28. ^ "BREAKING: Fearing plummet of emergency spillway at Oroville Dam, Oroville evacuated". Sacramento Bee. February 12, 2017. Retrieved February 12, 2017.
  29. ^ a b "Tons Of Rocks Eternalize Failing Oroville Dam Spillway". CBS Bay Area. February 13, 2017. Retrieved February 13, 2017.
  30. ^ "Updates: New storms approach, only officials confident Oroville Dam and spillways will hold up". Los Angeles Times. ISSN 0458-3035. Retrieved February 17, 2017.
  31. ^ Schmidt, Samantha and Hawkins, Dave (February thirteen, 2017). "'NOT a drill': 188,000 evacuated, emergency declared, as Calif's massive Oroville Dam threatens floods". Washington Mail . Retrieved February xiii, 2017.
  32. ^ "Sheriff Allows Oroville Dam Evacuees To Go Domicile". CBS SF Bay Expanse. February 14, 2017.
  33. ^ Serna, Joseph; Sahagun, Louis (February 17, 2017). "150,000 cubic yards of debris stand in the way of Oroville Dam'south hydroelectric plant restart". Los Angeles Times . Retrieved Feb 18, 2017.
  34. ^ "Fish evacuated from Feather River Hatchery". KRCR. February xi, 2017. Retrieved February xiii, 2017.
  35. ^ "The Latest: California lake impairment may nearly $100 million". NewsOK.com. February ten, 2017. Retrieved February 11, 2017.
  36. ^ "'Amazing engineering feat' saves millions of fish at Feather River Fish Hatchery". ChicoER. February 11, 2017. Retrieved February xiii, 2017.
  37. ^ Sabalow, Ryan (Feb 28, 2017). "Oroville Dam'south ability plant may be operational by Th". Sacramento Bee . Retrieved Feb 28, 2017.
  38. ^ Fimrite, Peter (February 28, 2017). "Dramatic new images prove scale of harm to Oroville Dam spillway". SFGate . Retrieved February 28, 2017.
  39. ^ Sabalow, Ryan (February 26, 2017). "Tin can Oroville Dam's badly damaged spillway agree upwardly through the rainy flavor?". Sacramento Bee . Retrieved March 1, 2017.
  40. ^ Sabalow, Ryan (February xiii, 2017). "Feds guild independent review of Oroville Dam spillway issues". Sacramento Bee . Retrieved February 23, 2017.
  41. ^ California Department of H2o Resources (November xx, 2017). "Oroville Spillways Incident, Board of Consultants". Archived from the original on January 30, 2018. Retrieved January 29, 2018.
  42. ^ Board of Consultants (December 20, 2017). "Reports from the Lake Oroville Spillways Recovery Project Board of Consultants". Archived from the original on January 30, 2018. Retrieved January 29, 2018.
  43. ^ a b Ingram, Elizabeth (February 22, 2017). "California DWR selects independent lath of consultants to investigate Oroville Dam". HydroWorld . Retrieved February 23, 2017.
  44. ^ DWR (October sixteen, 2017). "Lake Oroville 2017/2018 Inundation Control Flavour Operations Program" (PDF) . Retrieved January xxx, 2018.
  45. ^ Vartabedian, Ralph (May 12, 2017). "Land officials become slammed for the Oroville Dam spillway failure at Sacramento hearing". Retrieved May 31, 2019.
  46. ^ "Oroville Spillways Recovery". California Department of Water Resource. Retrieved December 9, 2019.
  47. ^ DWR (October sixteen, 2017). "Lake Oroville 2017/2018 Flood Control Season Operations Programme" (PDF) . Retrieved January 30, 2018.
  48. ^ Harvey, Chuck. "Kiewit Leads Stage Two of Oroville Dam Spillway Repairs". ConstructionEquipmentGuide.com . Retrieved August 7, 2018.
  49. ^ "DWR Uses Oroville Main Spillway". water.ca.gov . Retrieved April 3, 2019.

External links [edit]

  • Media related to 2017 Oroville Dam crunch at Wikimedia Commons
  • Oroville Spillways Incident, California Department of Water Resources
  • Photogallery of the incident from the California Department of Water Resource
  • Dramatic Satellite Images Evidence the Oroville Dam from Drought to Overflow
  • Independent Forensic Team Report

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Source: https://en.wikipedia.org/wiki/Oroville_Dam_crisis

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