Hendrickson Dam; Alan 1 Reservoir Report
Last Updated: December 6, 2025
Hendrickson Dam, also known as Alan 1, is a private earth dam located in Dunn, North Dakota, with a primary purpose of providing fire protection, stock, or a small fish pond.
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Summary
Built in 1960 by USFWS, this dam stands at a height of 9.95 feet and has a storage capacity of 89.3 acre-feet. It is state-regulated by NDSWC and has a spillway width of 165 feet, with a hazard potential rated as low.
The dam underwent structural modifications in 1994 and is equipped with a vertical lift outlet gate. Despite being labeled as not rated in terms of condition assessment, the risk assessment for Hendrickson Dam is moderate with a DSAC-assigned date pending. With a relatively small surface area of 10 acres and a drainage area of 1.05 square miles, this dam plays a vital role in water resource management in the region and adds to the diverse landscape of North Dakota.
As a significant feature in the St. Paul District, Hendrickson Dam serves multiple purposes while ensuring water security and environmental sustainability. With a risk management plan in place, this dam continues to be a valuable asset for the local community and a focal point for water resource and climate enthusiasts interested in the management of small-scale water infrastructure.
Years Modified |
1994 - Structural |
Year Completed |
1960 |
Dam Height |
9.95 |
River Or Stream |
SLOW CREEK-TR |
Primary Dam Type |
Earth |
Surface Area |
10 |
Drainage Area |
1.05 |
Nid Storage |
89.3 |
Outlet Gates |
Vertical Lift - 1 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
10 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
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. Investigations and studies are necessary.
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.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams 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, environment 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.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Hendrickson Dam; Alan 1