C. Sullivan shared a photo where water meets the perfect sunset! Click to view larger photo.

Looking for a summer getaway to escape the heat of the Valley? You might want to consider Flagstaff, and a visit to Upper or Lower Lake Mary. These lakes offer a number of outdoor activities and are open year-round.

Upper Lake Mary

Upper Lake Mary. Photo by Laura Garcia.

Lower Lake Mary and Upper Lake Mary, two reservoirs in the Flagstaff, AZ area, were formed by dams on Walnut Creek. The lakes are located about 12 miles southeast of Flagstaff, and Upper Lake Mary is further up in the Walnut Creek watershed from Lower Lake Mary. Lower Lake Mary is the older of the two, built in 1905 as an earthen dam to provide a water supply for Flagstaff. The lake is named after the eldest daughter of one of the wealthy lumber barons, the Riordan family, who built the dam.

Interestingly, water that pooled behind the reservoir was draining quickly due to karst features (landscape formed from the breaking up of soluble rocks such as limestone, dolomite, and gypsum. It is characterized by underground drainage systems with sinkholes and caves) that had formed within the Kaibab limestone. As a result, numerous sinkholes provided a direct conduit for water to flow from Lower Lake Mary directly into the aquifer system.

As a result, these sinkholes led to the construction of the more substantial concrete dam that forms Upper Lake Mary. The dam was built in 1941. This lake holds 16,000 acre-feet of water derived from the Upper Lake Mary Watershed. To this day, surface water from Upper Lake Mary continues to be an essential municipal supply for the City of Flagstaff, meeting up to 50 percent of the City’s water needs.

The City of Flagstaff established a watershed health monitoring program because this water source is so crucial. Nearly 80 percent of the City’s water supplies are derived from densely forested areas, and the Water Services Division is collecting data that can be used to inform forest managers on forest conditions that promote the stability and reliability of water resources.

Sunset on Lake Mary

Sunset on Lake Mary

Recreational facilities at these lakes are maintained by Coconino National Forest. These lakes offer fishing, water skiing, kayaking, canoeing, power boating, and sail boating. There are also picnic grounds, three nearby campgrounds, and several hiking and biking trails. During high-use months (around mid-April to mid-October), a fee is required to use the day-use areas.

Thanks to its elevation above sea level of 7,000 feet, summertime temperatures are always pleasant, and the lake’s scenery makes it one of the most popular recreational sites in the Flagstaff area.

Looking for even more places to explore in Arizona? Celebrate AZ Water with us by visiting one or more of these other amazing destinations.


This photo by C. Sullivan, is just one of over 1,000 entries for our Spring 2014 Celebrate AZ Water Photo Contest. It provided a stunning opportunity to celebrate the importance and wonder of water in Arizona and to reflect on one of our region’s most precious resources. View more of our favorite entries at our Celebrate AZ Water Photo Gallery.

Erin Young, the author of this article, is the Water Resources Manager with the City of Flagstaff Utilities Division, one of 19 Water – Use It Wisely partners to offer water saving advice and programs.

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