Springhill Geologic Park, and the ground under North Salt Lake's bench

It is a small city park on the north bench of North Salt Lake, on Springhill Drive, built on the surface of an old landslide. The ground moved slowly for years and damaged the homes that stood here, so the city bought and cleared them, seeded the surface with native plants, cut a gravel loop trail and added a small parking lot. Plaques along the trail read the rock layers and the geologic story of the bench. It is free and open year round, with no restrooms, water or shade.

It is on Springhill Drive on the north bench, just north of Eagle Ridge Drive, with a second trail entrance at Barry Circle. Printed addresses for it vary, so navigate to Springhill Drive itself and take whichever entrance you reach first. It is about a mile and a half, roughly five minutes uphill from City Hall, and the whole approach is ordinary residential street driving.

It is free, and there is almost nothing there beyond the ground itself. A small parking lot is the only facility. There are no restrooms, no drinking water and no shade. Dogs are welcome on a leash, with nowhere on site to fill a bowl, so carry water for one. The loop is gravel and dirt, a little over a mile at an easy half hour.

Three things, once you know to look for them. Ground distortion along the edges and the head of the slide, where the failure shows as low steps and tilts in the surface. Remnants of the old yards, bits of landscaping left from the demolished homes. And the drainage system built to catch spring water and carry it off the slope, which is the engineering that stopped the movement. Plaques along the path name the rock layers and the plants as you go.

Gravel dropped by ancient Lake Bonneville sits on top, over a weak, poorly drained layer of clay-rich volcanic ash, sand and silt that has weathered soft over a very long time. That soft layer is the slip surface: it holds when dry and moves when it fills with water. The Wasatch fault zone crosses the lower part of the slope, which is the reason the whole front is shaped the way it is, with mountains on one side and a dropped valley on the other.

Because the slow landslide came first and the park was the city's answer to it. From the late 1990s the ground under four streets began to move and damage homes. The Utah Geological Survey counts eighteen homes lost over about fifteen years. In 2012 the city won a federal mitigation grant, matched its own money, and used it to buy and demolish the damaged houses and to drain the spring water feeding the slide. By 2014 the cleared ground was a public park and a door onto the trails above.

It is a slow, historically active landslide that the state monitors, and the loop is an easy gravel walk. The movement was measured in feet over many years, fastest in wet springs, and the remediation drained the spring water that drove it. For a current reading on either North Salt Lake slide, the Utah Geological Survey is the body set up to answer, not a listing, a neighbor or a page like this one.

Speed. Springhill crept for about fifteen years and destroyed eighteen homes across four streets. The Parkway Drive slide two miles south let go in a single morning in 2014 and destroyed one home. Both sit on the same stack of Lake Bonneville gravel over weak volcanic sediment, and both slopes were opened up by twentieth century gravel pits. The Parkway Drive page carries the detail of that faster failure.

It is a reason to do the paperwork, not a reason to avoid the bench. Slow ground is a normal, mapped feature of building against the Wasatch Front, and a purchase in a mapped hazard area here runs through a site specific geologic hazard study. The Parkway Drive page lays out what that document set is and what to ask for. If you are weighing a hillside address, I can connect you with a Davis County agent who reads these studies for a living.