Dam Report

Upper Lake Mary dam

Arizona, USA Walnut Creek Hazard Significant
Today high
--
Tonight low
--
Dam height
38ft
Hazard rating
Significant
Loading current conditions…
Loading next 24 hours…
Loading 7-day outlook…
Upper Lake Mary -- None dam
Upper Lake Mary None · Walnut Creek
About this dam

Upper Lake Mary

Upper Lake Mary, located in Coconino, Arizona, is a captivating destination for water resource and climate enthusiasts. This local government-owned reservoir, completed in 1941, serves primarily for recreation and water supply purposes. With a capacity of 21,041 acre-feet and a surface area of 1,058 acres, Upper Lake Mary is a significant water source in the region, drawing from a drainage area of 54.3 square miles.

Standing at a height of 38 feet with a structural height of 49 feet, the earth dam on Upper Lake Mary impounds water from Walnut Creek. The reservoir boasts a spillway width of 360 feet and a maximum discharge capacity of 11,000 cubic feet per second. Despite its significant hazard potential, the dam's condition assessment in 2015 deemed it satisfactory, ensuring the safety and stability of the structure for water storage and recreational activities.

With its scenic location near Walnut Canyon National Monument and I-40, Upper Lake Mary offers a serene and picturesque setting for outdoor enthusiasts. The reservoir's moderate risk assessment and regular inspection schedule, every three years, highlight its commitment to safety and environmental stewardship. Whether for boating, fishing, or simply enjoying the natural beauty of the area, Upper Lake Mary is a must-visit destination for those interested in water resources and climate conservation.

StateNone
River / streamWalnut Creek
NID IDAZ00016
Owner typeLocal Government
Primary purposeRecreation
Dam typeEarth
Year built1941
Dam height38 ft
Dam length845 ft
Max storage21,041 AF
Normal storage16,576 AF
Surface area1,058.0 ac
Drainage area54.3 sq mi
Hazard potentialSignificant
ConditionSatisfactory
Last inspectionTue, 26 Jun 2018 00:00:00 GMT

Dam data reference

Condition Assessment

Satisfactory
No existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action.
Poor
A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.

Hazard Potential Classification

High
Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environmental damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Detailed forecast

Plan around the weather

Same NOAA / yr.no feed Snoflo's iOS app uses. Watch the precipitation column on the meteogram -- rain on the basin upstream typically lifts inflow 24-72 hours later.

Hourly detail

Next 5 days, hour by hour

Temperature line with weather symbols on top, snow + rain accumulation as columns, humidity as a dotted line.

Loading hourly forecast…
Deep dive

5-day forecast table

Every 3 hours, broken out across temperature, snow, rain, humidity, and wind. Each cell is colour-coded relative to the column min/max.

TimeConditionTemp (°F)Snow (in)Rain (in)Humidity (%)Wind (mps)Wind dir
Loading detailed forecast…
Long-term outlook

15-day temperature & precipitation

Daily temperatures, snow, and rain projected over the next two weeks.

Loading 15-day outlook…
Regional inflow

Nearby streamflow gauges

USGS streamgauges around Upper Lake Mary -- inflows here typically show up in storage 24-72 hours later.

Track Upper Lake Mary in the Snoflo app

Save this dam as a favorite and get the local NOAA / yr.no forecast plus regional flow context wherever you are.

FAQ

About Upper Lake Mary

Where does the data for Upper Lake Mary come from?

Structural and regulatory data come from the U.S. Army Corps of Engineers' National Inventory of Dams (NID). Weather forecast comes from NOAA / yr.no -- the same feed Snoflo's iOS app uses.

How often is the report updated?

NID structural data refreshes annually as the Corps publishes updated assessments. The weather forecast refreshes throughout the day.

What does the Significant hazard rating mean?

The Corps of Engineers' hazard potential classification grades probable consequences if the dam fails: High = probable loss of human life; Significant = no probable loss of human life but possible economic loss / environmental damage; Low = no probable loss of human life, only minor economic / environmental losses. See the Dam Data Reference card above for the full definitions.

What's "% of normal"?

The current storage value compared to the historical average storage on this calendar day. 100% = right on average; values above 100% mean above-normal storage (wet year); values below mean below-normal (dry year or drought).

Can I get alerts when storage crosses a threshold?

Yes -- alerts are managed in the Snoflo iOS app. Favorite this dam, set a threshold, and you'll get a push the moment conditions cross.

More reservoirs

Other water bodies near here

Snoflo-tracked reservoirs and dams within driving distance of Upper Lake Mary.

Premium feature

Favorites and alerts are part of Snoflo Premium. Save reservoirs, set storage thresholds, and get push notifications when conditions cross.

Upgrade to Premium Not now
🔔

Manage alerts in the Snoflo app

Custom alerts are configured in the iOS app -- favorite this dam, set a threshold, and you'll get a push the moment conditions cross.

Open App Store