Pierson-upper is an earth dam located in Washington County, Oregon, built in 1965. It carries a Low hazard potential classification.
Dam profile
NID height · 31 ft31 ft tall and 120 ft long, taller than 72% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Pierson-upper
The primary purpose of Pierson-upper is irrigation. The dam stores and diverts water for agricultural irrigation, supporting farming operations in the surrounding area. The dam is owned by Jeffery W. Geiger (private). It impounds the Tualatin River, Trib to near Individual Residences.
The dam stands 31 feet tall and stretches 120 feet across, creates a reservoir covering 1 acres, has a maximum storage capacity of 18 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1965, the structure is well into its service life at over 50 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. The most recent inspection on record was 03/17/2015. That was over 11 years ago.
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Location
| State | Oregon |
| County | Washington |
| Nearest City | Individual Residences |
| River/Stream | Tualatin River, Trib to |
| Coordinates | 45.45643, -123.06061 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 31 ft |
| Dam Height | 31 ft |
| Dam Length | 120 ft |
| Year Completed | 1965 (61 years old) |
Storage & Hydraulics
| NID Storage | 18 acre-ft |
| Max Storage | 18 acre-ft |
| Normal Storage | 16 acre-ft |
| Surface Area | 1 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 205 cfs |
Ownership & Safety
| Purpose | Irrigation |
| Owner | Jeffery W. Geiger |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 03/17/2015 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | OR00426 |
| Federal ID | OR00426 |
| More Info | State Dam Safety Program |