NAVAJO LAKE

Navajo Lake has no surface outlet. Nothing flows out of it. What leaves it goes down through holes in its own floor, and then it splits.

The federal survey wrote an entire chapter of a professional paper about this in 1964, and the sentence that matters is this one 1:

Read that again. The continental divide between the Great Basin and the Colorado does not run past this lake. It runs through the water coming out of it.

The split is approximate and the federal survey says so. It comes from tracer tests run at particular flow rates in 1954 1. Nobody has published a better number since, and a later federal report says the boundaries between the groundwater basins up here still need more dye tracing to define 24.

This is not inference. In August and September 1954 the federal survey released water from the lake into individual numbered sinkholes and dyed it, then waited at both springs with a stopwatch 1.

Velocities: 5.6 to 12.5 feet a minute to Cascade Spring, 5.8 feet a minute to Duck Creek Spring 1. A separate trace poured a pound and a half of fluorescein into the Duck Creek Sinks on 24 August 1954 and picked it up at Lower Asay Spring 68 hours later 1.

Those 1954 travel times are still the numbers in the modern federal literature. The 2010 Markagunt Plateau hydrogeology report reprints 8.5 hours and 53 hours 2.

Two agencies describe the conduit differently, and one of them is describing the wrong rock.

The geologists are right. The lava is the dam, not the pipe. The water goes down through the basalt and then dissolves its way through limestone underneath it, which is what karst is. This page uses the geological survey's description and prints the Forest Service wording so you can see where the common version came from.

Cascade Spring rises 6,400 feet south of the sinks and 160 feet lower 1, at the Pink Cliffs escarpment 3.

The lake exists because lava blocked a valley. The federal survey 1: it "was formed by a lava flow which cut off the natural surface drainage of Duck Creek, a headwater tributary of the Sevier River." The flow came from a volcanic cone about half a mile northeast of the sinks, and a second cone seven miles east blocked the same valley again.

But a lava dam leaks. Before the dike went in, the lake "would drain almost dry during drought years" 21.

Who owns the dike could not be established. The 2023 project names the wildlife division as lead with the water resources division, the Dixie National Forest and Kane County as partners 20, and states no owner. The federal dam inventory and the state dam safety database both proved unreachable for this structure, so no federal identifier, official height, hazard class or inspection date is printed here.

The dike protects the western three quarters. It does not stop the sinks working. The federal survey recorded that on 21 July 1954 "the water over the sink area had been completely drained by the sinks" 1.

Two numbers give the range this basin swings through 1. Inflow in 1955 and 1956 was 630 and 550 acre feet, about 14 percent of the twenty one year average. In 1958 it was 11,710 acre feet.

The same report raised a possibility it could not rule out: that the underground channels might enlarge to the point of "complete underground piracy" 1. That was 1964. Nothing found here says whether anyone has looked since.

All three have drinking water and flush toilets. Te-Ah has the only dump station. Navajo Lake Campground has a primitive dirt boat landing for small craft inside it 17. The Forest Service lists a boat launch at the lake, and boats, lodging, fuel and limited supplies at private resorts on the south shore 11. There is no potable water at the lake site itself 11, only in the campgrounds.

The Forest Service page and the federal booking system count Navajo Lake Campground's site types differently, 12 standard and 4 double against 15 and 1 14 17. Both agree on 11 walk in tent sites and 27 total.

If you are standing at Cascade Falls, the water in front of you was in Navajo Lake eight and a half hours ago 1. From the falls it becomes the North Fork of the Virgin River.

The nearest gauge to the falls, on the North Fork near Glendale, stopped in 1978 9. The nearest live one is thirty miles south at Springdale, inside Zion National Park, draining 344 square miles 8. That is the live river number on this page, and this lake is a small part of what it measures.

Downstream of Zion the Virgin runs through Washington County, past the reservoirs Fathom has already written up: Quail Creek, Sand Hollow and, on the Santa Clara tributary, Gunlock. The native fish those three carry a kill on sight rule for smallmouth bass to protect live in this same river system.

Utah Highway 14 runs east from Cedar City. The campgrounds are about 25 miles out, then two and a half to four and a half miles down Navajo Lake Road 14 16.

The lake surface is at 9,035 feet 1 4. The snow station four miles northwest sits at 9,830 10. That elevation is not a detail:

• The season is short. All three campgrounds and the falls trail run roughly Memorial Day to Labor Day 12 14. Everything else in the year is snow.
• The water is cold whenever you get in it. The one reading anyone has published was 47 degrees in the third week of May 18.
• Any dive here is an altitude dive. Sea level tables and default computer settings are wrong at 9,035 feet. This page is not dive instruction and gives no schedule. It just says the altitude is not optional to account for.

No winter closure statement for Highway 14 could be sourced from the state transport department, so none is printed. Check road conditions rather than this page.