SCOFIELD
The third dam in this valley
The first failed in 1917 while it was still being built. The second partly failed in 1928. A war got the third one built, and in 2004 Reclamation found its spillway could take it down.
There have been three attempts to hold water in this valley and the first two did not hold .
| Attempt | What happened |
|---|---|
| Mammoth Dam, begun 1908 by the Mammoth Reservoir Company | Failed on 25 June 1917, while it was still only partly built |
| The original Scofield Dam, built 1925 to 1926 by the Price River Water Conservation District | Partially failed in May 1928. It kept deteriorating. The spillway was lowered for the last time in 1942, cutting capacity to 30,000 acre feet |
| The present dam | President Roosevelt authorised a replacement in June 1943 because the failing dam threatened railroads, coal mines and wartime infrastructure. Built 1943 to 1946, completed 15 June 1946 |
So the dam standing today is not a repair of the 1926 dam. It is a replacement, and the thing that got it built was a war.
In 2004 Reclamation published a safety of dams assessment for Scofield, and the failure mode it identified is specific and uncomfortable :
The joints had no waterstops and no shear reinforcement. The concrete had also suffered freeze thaw damage and alkali silica reaction, and Reclamation concluded that "further efforts to repair these conditions would not be effective" . The proposal was to replace the spillway structure and the crest gate house outright.
The bridge carrying State Highway 96 across the spillway scored a sufficiency rating of 21.8 percent against a replacement threshold of 50, and was rated structurally deficient and functionally obsolete .
No seismic deficiency is identified anywhere in that assessment. If you have heard Scofield described as a seismic problem, nothing found here supports it.
Every other dam Fathom has written up sits in the Utah Division of Water Rights dam safety database, usually with a more recent inspection than the federal register carries. Scofield does not, and the reason is statutory.
The state hazard mitigation plan's dam failure chapter records that the 1990 legislature directed the state engineer to regulate all dams in Utah, including federally owned dams, except those owned by the Bureau of Reclamation .
Scofield is a Reclamation dam. So it falls outside state jurisdiction entirely, and the record you would normally check does not exist for it.
Reclamation holds 7,800 acre feet of dead pool below elevation 7,586 feet, and the stated reason is not engineering : it "allows most fish to survive if the reservoir is drawn down to minimum levels."
That is an explicit fishery protection design feature in a federal irrigation dam, and it is the sort of thing that usually goes unmentioned. Total capacity is 73,600 acre feet, active capacity 65,800, and the difference is water nobody is ever allowed to take .
The town of Scofield sits beside the reservoir. On 1 May 1900 at 10:28 in the morning the No. 4 entry of the Winter Quarters mine exploded and 200 men and boys were killed .
The mine was worked from 1875 and operated by the Pleasant Valley Coal Company. The state mine inspector, Gomer Thomas, attributed the explosion to "a heavy shot of giant powder or loose powder exploding" . The federal engineering record puts the significance plainly: the mine "is significant as possible the first coal mine in Utah. The May Day disaster of 1900 killed 200 miners and prompted the development of organized labor in Utah" .
The state history office calls it the worst mine disaster in America to that time . The cemetery is on the Utah State Register of historic places, not the National Register ; no National Register listing or reference number for it could be found, and no agency publishes a coordinate for the cemetery, so it is not pinned on the map above.
Impaired since 2000
Phosphorus, and an oxygen problem in the bottom fifth of the water that has been measured once, in 1980. Plus a storage station that, unusually, does what it says.
The shape at the top of this page was traced by hand for a print, then scaled to the extent of the USGS water body polygon and measured off its own coordinates.
It is 1.7 percent apart on proportion, which is the tightest of any lake in this series so far.
| Scaling | Traced area | Against the federal polygon |
|---|---|---|
| One scale factor, matched on length | 2,784 acres | 1.2 percent large |
| Stretched to fill the extent on both axes | 2,832 acres | 3.0 percent large |
| One scale factor, matched on width | 2,882 acres | 4.8 percent large |
The drawing measures 5.16 miles on its long axis against a federal extent of 5.02 miles. The whole plausible range of areas spans three and a half percent.
Federal polygon extent 5,029 metres by 8,075 metres, which is 3.12 by 5.02 miles. Permanent identifier 37983005, reach code 14060007001312 .
| Measure | Figure | Source |
|---|---|---|
| Surface area | 2,750 acres, 11.128 sq km | USGS water body polygon |
| 2,800 acres | Reclamation environmental assessment | |
| 2,810 acres | Reclamation, the same assessment, a different table | |
| Surface elevation | 7,616.5 ft at full pool | Reclamation |
| 7,618 ft | USGS water body polygon, 2,321.97 metres | |
| 7,620 ft | The federal storage station | |
| Maximum depth | 47 ft | USGS water supply paper 2247 . The only depth published anywhere |
| Mean depth | not published | |
| Total capacity | 73,600 acre feet | Reclamation |
| Active capacity | 65,800 acre feet | Reclamation |
| Dead pool | 7,800 acre feet below 7,586 ft | Reclamation |
| Average annual inflow, 1942 to 1953 | 57,600 acre feet | Reclamation |
Scofield is a listed impaired water. Reclamation's own environmental assessment records the 303(d) listing for impairment of the class 3A cold water fishery, with the parameters of concern given as "total phosphorus concentrations, low winter dissolved oxygen concentrations and nuisance algal blooms" .
There is a total maximum daily load for it :
| Item | Value |
|---|---|
| Pollutant | Total phosphorus, with dissolved oxygen added later |
| Approved | 23 May 2000, updated 1 September 2000 to add dissolved oxygen |
| Target load | 4,842 kilograms a year of total phosphorus |
| Endpoints | Shift away from blue green algae dominance; a dissolved oxygen minimum of 4.0 mg/L in half the water column; trophic state index 40 to 50 |
The underlying work goes back further than that: a Clean Lakes study in 1983 and a phosphorus control restoration study in 1990 .
The current assessment category in Utah's latest integrated report could not be obtained, and the TMDL document itself could not be retrieved; the approval details above come from the federal summary of Utah approvals .
Utah's warning threshold is more than 20,000 cyanobacteria cells per millilitre, or microcystin above 4 micrograms per litre, or cylindrospermopsin above 4, or anatoxin-a detected at any level at all .
| Date | What happened |
|---|---|
| 31 August 2016 | Closed to all water recreation. Reopened 15 September. Campgrounds stayed open. The wildlife division reported a fish kill "in the thousands" on 27 August, along with dead waterfowl and bats |
| 30 October 2018 | Monitored, no advisory |
| 19 August to 22 October 2024 | Warning advisory, issued by the Southeast Utah Health Department. Water tested clean on 30 May, 18 June, 10 July, 22 July and 5 August; first bloom report 16 August. Monitoring ended 2 December with the bloom possibly still present |
This is a small thing that is worth saying because it has been false on the last three pages Fathom built. The federal storage station here, 09311000:UT:BOR, advertises daily, semimonthly and monthly series .
All three of them return data. Quail Creek, Gunlock and Sand Hollow all advertise a daily series and all three return an empty list when you ask for it. Scofield does not. The live storage figure on this page is a daily reading.
There is also, unusually, a real inflow gauge: USGS 09310500, Fish Creek above the reservoir, active with a daily record running back to 1 June 1931 and draining 60.1 square miles . A second live gauge, on the White River below Tabbyune Creek near Soldier Summit, has run since 19 May 1967 and drains another 75.6 square miles of the same basin north east of here .
There is no snow telemetry station anywhere in this basin. A query of the federal network for the Price River hydrologic unit returns three stations and all three are the gauges above.
Where everything is
Six places, seventy seven campsites the state counts as one number, and a park that stays open through the winter because winter is the point.
Scofield State Park sits at about 7,600 feet in the Manti-La Sal mountains and is open year round . Seventy seven sites across two loops: Madsen Bay on the north shoreline, recently renovated with electric and water and paved pads for larger trailers, and Mountain View near the dam on a shoreline terrace for smaller trailers and tents. Showers are only at Mountain View.
| Fee | Amount |
|---|---|
| Day use, vehicle up to eight people | 10 dollars |
| Day use, senior | 5 dollars |
| Walk in or bicycle, per person | 5 dollars |
| Camping, standard | 20 dollars |
| Camping, partial hookup | 30 dollars |
| Camping, full hookup | 35 dollars |
| Group overnight, Mountain View, 25 to 50 people | 50 dollars |
| Extra vehicle at a campsite | 15 dollars |
| Reservation | 8 dollars |
All from the park fee page , which carries no effective year, so treat these as the posted amounts rather than a certified 2026 schedule. Hours are 07:00 to 22:00 in summer and 08:00 to 17:00 in winter .
Scofield is a major ice fishery, and the park says so in its own description of itself: in winter you "ice fish, snowmobile, and cross-country ski in a spectacular mountain setting" . The park stays open, unlike most.
Utah State Parks publishes ice thresholds :
- Four inches of good clear ice minimum, to walk on.
- Six or more inches for a snowmobile or an ATV.
- Cars, trucks, vans and SUVs are not permitted on the ice at state parks. That is a rule, not advice.
- "Clear ice is capable of holding more weight than cloudy ice." Late season ice in March and April is flagged as especially hazardous.
The winter dissolved oxygen problem that put this reservoir on the impaired list is the same thing that makes it a winter fishery worth protecting. Under ice the water column inverts, the surface sits at 1.5 to 2.5 degrees Celsius, and below elevation 7,590 feet the oxygen falls under 2 mg/L for most of the year .
That is roughly the bottom fifth of the stored water, and it is why the phosphorus target exists: phosphorus feeds the algae, the algae die and decompose, and the decomposition takes the oxygen .
Quagga mussels are not here. The wildlife division, updated 21 April 2026: "the presence of quagga and zebra mussels in Utah is currently limited to Lake Powell" . Scofield is not listed.
The best documented chub problem in Utah
Three rotenone treatments that did not hold, a survey where half the anglers asked for a fourth, and a protected slot limit that exists so the big fish keep eating.
Utah chub
In 2006 the division caught 2.7 a net night. In 2009 it caught 357.3. Somebody put them here in 2005 and the reservoir has never been the same water since.
357.3 a net night in 2009Tiger trout
Both Utah state records for the species came out of this reservoir. It was also the fish the biological control programme was built on, and its own catch rate fell from 13.0 a net night to 1.4 between 2009 and 2016.
Both state records, hereCutthroat trout
One of three predators the division credits with finally reducing the chub. The only trout whose net catch rose while the chub were at their worst.
4 trout limit, size rules applyTiger muskellunge
Prescribed in the 2017 plan at no more than two and a half fish an acre, and named in 2024 as one of the three that worked.
Stocked as a predatorWiper
A white bass crossed with a striped bass. Prescribed in 2017 at 400 fry or 40 fingerlings an acre, and named in 2024 as one of the three that worked.
Stocked as a predatorRainbow trout
Twenty a net night in 2006. Zero in 2016. The division kept stocking them and stopped catching them.
0 a net night in 2016The division has gill netted this reservoir for decades and the numbers are published in its 2017 management plan . Fish per net night:
| Year | Rainbow | Cutthroat | Tiger trout | Utah chub |
|---|---|---|---|---|
| 2006 | 20.0 | 4.7 | 5.0 | 2.7 |
| 2009 | 9.7 | 10.7 | 13.0 | 357.3 |
| 2013 | 1.4 | 14.2 | 8.6 | 157.2 |
| 2016 | 0.0 | 8.8 | 1.4 | 135.4 |
Chub went up by a factor of 132 in three years. Rainbow trout went to zero. The plan's stated objective was to get chub down to 55 a net night or fewer within five years .
Rotenone is still on the table. The 2017 plan says a treatment "is being planned and will be initiated if the Goals and Objectives of this plan are not reached," with environmental review and funding groundwork already under way . Nothing found here says a treatment has happened since 1991.
In 2016 the division ran an angler survey at Scofield. It approached 2,523 people and 2,505 took part, a participation rate of 99.29 percent .
| Question | Result |
|---|---|
| Satisfied with the quality of the trout fishery | 8.48 percent |
| Not satisfied | 53.03 percent |
| Had started fishing Scofield within the previous ten years | 65.28 percent |
| Supported treating the reservoir with rotenone | 53.14 percent for, 27.66 percent against |
| Supported treating the tributaries | 57.60 percent |
| Supported stocking sterile walleye | 72.36 percent |
| Supported stocking wiper | 64.06 percent |
One angler comment printed in the results says it as well as any table : "The last two trips combined we caught 160 chubs to 4 trout."
Scofield held a Blue Ribbon designation, lost it in 2017 because of the chub, and the Blue Ribbon Fisheries Advisory Council voted to restore it. The division's own release, published December 2024, says the vote was "last month" .
The release credits three fish: managers "began stocking tiger muskies, wipers and cutthroat trout. These sportfish species feed on other fish and have since helped reduce and control the Utah chub numbers" . It quotes Brad Walker, the Scofield State Park manager, and Trina Hedrick, the division's sportfish coordinator, and puts the statewide total at 42 waterbodies plus two mountain areas.
This page does not resolve that. What is sourced is that the council voted to restore the designation in November 2024. Whether it currently holds it could not be confirmed from any rendered list.
Note also what the release does not credit: tiger trout, which was the species the biological control programme was originally built on, and whose own net catch fell from 13.0 to 1.4 between 2009 and 2016 . No division statement evaluating the tiger trout programme specifically could be found.
The Scofield entry, from the division's own digital guidebook :
- "Limit 4 trout (a combined total)."
- "No more than 2 may be cutthroat or tiger trout under 15 inches, and no more than 1 may be a cutthroat or tiger trout over 22 inches."
- "All cutthroat and tiger trout from 15 to 22 inches must be immediately released."
- "Trout may not be filleted, and the heads or tails may not be removed in the field or in transit."
- "Any trout with cutthroat markings is considered to be a cutthroat trout."
The middle rule is a protected slot. It exists so the fish big enough to eat chub stay in the water. The fourth is an enforcement rule, and it is confirmed independently in the 2026 guidebook at page 23 and in the administrative code : at Strawberry, Scofield, Lost Creek and Panguitch you may not fillet trout or salmon or remove their heads or tails in the field or in transit. A filleted fish cannot be measured against a slot limit.
The quoted bullets are from the digital edition last updated May 2025. The 2026 guidebook PDF resists automated reading and truncates before the S waters, so those exact bullets could not be re-verified against the current printed guidebook. Read the guidebook itself before you act on any of this.
The division's record list was read row by row across all five tables. Exactly two rows name Scofield, and both are tiger trout .
| Record | Figure | Angler | Date |
|---|---|---|---|
| Catch and keep | 19 lbs 2 oz, 37 and a half inches | Jake Trane | 2013 |
| Catch and release | 32 inches | Kaleb Nelson | 9 December 2023 |
A tiger trout is a brown crossed with a brook, and it is sterile. Both of those fish grew that big eating something, and the something was almost certainly chub.
No stocking numbers for Scofield could be obtained. The division's stocking tool renders one alphabetical statewide table; the 2026 view truncates around the letter L and the 2025 view truncates around G. Scofield is unreachable in both.
What to watch for
Four inches of clear ice, no vehicles on it, and an algae season that starts after the spring tests come back clean.
Scofield freezes and is fished hard through the ice. Utah State Parks publishes the thresholds : four inches of good clear ice to walk on, six or more for a snowmobile or ATV, and no cars, trucks, vans or SUVs on the ice at state parks at all.
That last one is a prohibition rather than a recommendation, and it is the one most likely to be ignored on a big flat reservoir with a road running to it.
The wildlife division adds ice picks, a throw rope, a companion and flotation bibs to that list. Neither agency names Scofield specifically, and no ice related incident here could be sourced.
Summer surface temperature in the one study anyone has published was about 21 degrees Celsius, with the bottom at about 13 . That was 1980. No agency has published a water temperature for this reservoir since 1984.
The algae risk is real and documented. In 2016 the reservoir was closed to all water recreation for a fortnight, with a fish kill in the thousands and dead waterfowl and bats . In 2024 a warning advisory ran from 19 August to 22 October .
- No drowning, recovery or fatality at Scofield Reservoir could be sourced. Not from the state, not from the park, not from news. That is a genuine negative and not the same as saying none has happened; no agency publishes a complete incident record.
- No hazard classification for the dam. Utah does not regulate Reclamation dams and the federal inventory could not be retrieved, so this page gives no hazard class, no condition assessment and no inspection date.
- No current water temperature, and no live reservoir elevation. The elevation gauge stopped in 2003 .
- No boat ramp coordinate, and no coordinate for either campground loop.
What does exist, and works, is the daily storage record and a genuine inflow gauge that has run since 1931. On a page like this that counts as unusually well measured.
A majority of the people who fish this reservoir asked the state to kill everything in it.
Fathom Restoration is a Utah 501(c)(3) that runs volunteer dive cleanups and is built to pull what does not belong out of Utah water, statewide.
Donate to Protect ScofieldEvery figure on this page is quoted from the source named beside it.
Sources
How these were checked
Numbered sources are agencies. Lettered sources are everything else. Three things were resolved before they reached this page. Scofield Dam was replaced after a 1928 partial failure, not modified, and a war is what got the replacement authorised. The 2004 safety of dams finding is about the spillway, not about seismic risk, and nothing found here supports a seismic story. And there is no chub rule at Scofield: no mandatory kill, no no-limit provision, nothing chub specific in the entry at all. Where agencies disagree, all of them are printed: that happens over the height of the dam, the surface area, the surface elevation, and whether this reservoir currently holds a Blue Ribbon designation.Scofield Project. The Mammoth Dam failure of 1917, the 1928 partial failure, the wartime authorisation and the present dam
Scofield Dam, dimensions and specifications. Structural height 96 feet, crest 575 feet, total capacity 73,600 acre feet
Final environmental assessment, safety of dams modifications and bridge reconstruction, Scofield Dam, 2004. Hydraulic jacking of the spillway slabs, the bridge rating and the population at risk
The same assessment, chapter 1. The transverse joint failure mode
The same assessment, chapter 3. The 303(d) listing, the surface area and the average water stored
Scofield Reservoir, Provo Area Office. The downstream communities
Limnology of Scofield Reservoir, Utah. Waddell, Darby and Theobald, 1985, water supply paper 2247. The 47 foot maximum depth, the dissolved oxygen profile and the sedimentation
National Hydrography Dataset, water body permanent identifier 37983005, reach code 14060007001312. The surface area, the elevation and the polygon extent this page measures against
Fish Creek above reservoir near Scofield, site 09310500. Active, daily record since 1 June 1931
Scofield Reservoir near Scofield, site 09311000. Reservoir elevation, 1 October 1941 to 29 September 2003, then discontinued
White River below Tabbyune Creek near Soldier Summit, site 09312600. Active since 1967
Scofield Reservoir storage, station 09311000:UT:BOR. Daily, semimonthly and monthly series, and all three of them work
Scofield Reservoir fishery management plan, 2017. The rotenone history, the gill net catch rates and the predator prescriptions
Scofield Reservoir angler survey results, 2016. Two thousand five hundred and five anglers
Scofield Reservoir designated as new Blue Ribbon fishery, December 2024. The 2017 loss of status and the predators credited with reversing it
Blue Ribbon Fisheries programme allocation, 15 July 2026, which gives the current count as forty one waters and does not name Scofield
Utah Fishing Guidebook 2026. The filleting rule at page 23, and the statewide limits
Administrative Rule R657-13. R657-13-16 carries the filleting rule and R657-13-14 covers the taking of nongame fish
Record fish caught in Utah. Two rows name Scofield and both are tiger trout
Quagga and zebra mussels, updated 21 April 2026. Utah's infested waters are limited to Lake Powell
Scofield Reservoir recreational monitoring, including the 2024 warning advisory
Recreational health advisory guidance for harmful algal blooms, and the warning thresholds
Algal bloom temporarily closes Scofield Reservoir, 31 August 2016
Approved total maximum daily loads, watershed management programme, which lists the Scofield Reservoir TMDL
Summary of approved total maximum daily loads in Utah. The Scofield approval dates, the phosphorus target and the dissolved oxygen endpoint
Dam failure hazard chapter, state hazard mitigation plan. The 1990 statute that put every dam in Utah under the state engineer except those owned by the Bureau of Reclamation
Ice safety. Four inches of clear ice to walk on, and no vehicles on the ice at state parks
Winter Quarters Mine, historic American engineering record UT-44, prepared by Senulis. The date, the death toll, the operator and the burials
The Scofield mine disaster. History Blazer, January 1995
Utah rules for specific waters, the digital edition of the division guidebook, last updated 14 May 2025. The Scofield entry, which carries no Blue Ribbon marker
What these numbers are measuring
The storage figure is a daily reading, and that is worth noting. Station 09311000:UT:BOR publishes daily, semimonthly and monthly series and all three of them return data . Three other Utah reservoir stations Fathom has built pages on advertise a daily series and return an empty list when asked for it. This one works.
Percent of capacity is arithmetic, not a measurement. It divides the storage reading beside it by the 73,600 acre feet Reclamation publishes as total capacity . Reclamation also publishes 65,800 as active capacity , and using that would make this percentage larger. The state park publishes its own percent full figure and it will not necessarily match either.
The creek card is real inflow. USGS 09310500 sits on Fish Creek above the reservoir, draining 60.1 square miles, with a daily record running back to 1 June 1931 . That is rarer on these pages than it ought to be: most of the reservoirs in this series have no live inflow gauge at all.
Nothing measures the water level or the temperature of this reservoir. The elevation gauge stopped on 29 September 2003 and the in reservoir sampling site stopped in 1984. The last published water temperature for Scofield is from a study run in 1979 and 1980 .
The forecast is a point forecast from the National Weather Service for the middle of the reservoir. It is weather, not water conditions, and it is not ice thickness.