WILLARD BAY

Willard Bay does not sit in a canyon and nothing flows through it. It is an off channel reservoir: a rough rectangle of fresh water held on the Great Salt Lake floodplain by an earth dike that runs 14.5 miles all the way around it 2 1.

The water is carried in. It is diverted from the Weber River, with Ogden River flows in it, at the Slaterville Diversion Dam about two miles west of Ogden, and run eight miles north up the earth lined Willard Canal 3 2. It goes in during spring runoff when nobody wants it, and it comes back out through pumping plants during the irrigation season.

The formal name of the structure is Arthur V. Watkins Dam. Almost nobody uses it. The register carries Willard Bay Reservoir as an alternate name for the same object 1.

The drainage area behind it is 16 square miles 1. For comparison, the drainage behind Pineview is 306. That single number is the clearest statement of what off channel means: essentially nothing runs into this reservoir on its own.

On 13 November 2006 a foundation seepage erosion failure mode was discovered. Reclamation treated it as an emergency and determined there was a substantial probability of catastrophic failure. A safety of dams modification followed, to restore full capacity and to add modern seepage control 4.

That is the thing worth understanding about this water. A dam across a canyon fails into a canyon. A fourteen and a half mile ring dike holding two hundred thousand acre feet of water above a floodplain, with Interstate 15 and the towns of Willard and Perry on the other side of it, fails differently.

Seventeen million cubic yards of embankment went into it 22 4. It was built between 1957 and 1964 2.

Willard Bay held 105,791 acre feet on 10 August 2026 5, against a capacity Reclamation puts at 215,120 2. The park published 48 percent on 5 August 13. Those agree.

The reason it was drawn down is documented. In July 2025 the water district lowered the reservoir to replace corroded mid 1970s steel siphon pipes running through the south dike, a 16 inch and a 24 inch, with a single 48 inch line. Roughly eight million dollars, targeted at 50 percent capacity by 1 August 2025, and expected to run through December or January A.

On the evening of 18 March 2013 a cracked seam in an eight inch Chevron products pipeline released diesel about a quarter mile east of the Willard Bay shoreline 8.

What was measured, by the state, in April 2013: trace concentrations in the parts per billion range outside the booms, with 49 of 69 samples nondetect. Trimethylbenzenes above tap water screening levels. Toluene and xylenes above aquatic life screening levels but below human health thresholds 7.

Fifteen fish were sampled on 9 May 2013, wipers, catfish and gizzard shad. The laboratory detected no diesel contamination and the state concluded the fish were safe to eat 7.

Wildlife recorded by EPA: six beavers captured, five of them oiled, two dead birds, one dead muskrat, and more than a hundred and ten dead three spine sticklebacks, which are a non native invasive fish 8.

The federal penalty covered this spill together with the Red Butte Creek releases, so it is not all attributable to Willard Bay 9.

DWR's 2023 monitoring report names nineteen species in this reservoir 10. Eight are drawn above. The other eleven are bluegill, green sunfish, largemouth bass, yellow bullhead, black bullhead, Utah sucker, Utah chub, logperch, redside shiner, spottail shiner and mosquitofish.

Willard Bay is also open to underwater spearfishing, and it is one of the waters where dead yellow perch may be used as bait 11.

One verification caveat. These four bullets were read from the official digital guidebook, which carries a May 2025 update stamp. The 2026 PDF confirms Willard Bay is in the specific waters list but the entry itself sits past the page the fetch could render. Check the printed guidebook before you rely on them.

A wiper is a cross between a white bass and a striped bass 11. They do not reproduce, so the population is entirely a stocking decision. DWR was putting in a million fry and five thousand catchable fish a year as of the 2023 report, and notes that fry were pursued from an out of state source because state hatchery production was not adequate 10.

DWR's own 2023 report records a negative trend in wiper abundance since 2014 10. Nets in autumn 2024 were turning up many fish in the twelve to fourteen inch range, which is a recruiting class rather than a trophy one.

Two things could not be sourced: the year wipers were first stocked here, and any 2025 or 2026 stocking count. Willard Bay does not appear in DWR's public stocking database in any year checked, which is a gap in the database rather than evidence nothing was stocked.

The whole predator fishery here was built on gizzard shad. Two DWR documents disagree about whether there are any left.

Both are Utah DWR. Neither corrects the other. If the shad really have collapsed then the smallmouth bass going from a fifth of the net catch to four fifths, and the perch climbing since 2017, are the system rearranging itself around the gap. That is an inference and it is labelled as one.

It also explains the fourth special rule. Possession of gizzard shad here, dead or alive, is unlawful unless it was bought commercially preserved 11, which is a rule about not moving them between waters.