Thorald Dam

Thorald Dam is an earth dam located in San Juan County, Washington, built in 1988. It carries a Low hazard potential classification.

About Thorald Dam

The primary purpose of Thorald Dam is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by San Juan Preservation Trust (private). It impounds the Tr-parks Bay.

The dam stands 19 feet tall and stretches 400 feet across, creates a reservoir covering 7 acres, has a maximum storage capacity of 98 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1988, the structure is 38 years old.

This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life.

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Low Hazard ConditionEmergency Action Plan: Not Required

Location

StateWashington
CountySan Juan
River/StreamTr-parks Bay
Coordinates48.56242, -122.97161

Physical Characteristics

Dam TypeEarth
NID Height19 ft
Dam Length400 ft
Year Completed1988 (38 years old)

Storage & Hydraulics

NID Storage98 acre-ft
Max Storage98 acre-ft
Normal Storage85 acre-ft
Surface Area7 acres
Drainage Area0 sq mi
Max Discharge15 cfs

Ownership & Safety

PurposeIrrigation
OwnerSan Juan Preservation Trust
Owner TypePrivate
Hazard ClassificationLow
Emergency Action PlanNot Required

Identifiers

NID IDWA00579
Federal IDWA00579
More InfoState Dam Safety Program

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