Lyon County Roadgrade Dam 10-98-48 Reservoir Report
Nearby: Lee Dam Folkerts Dam
Last Updated: December 13, 2025
Lyon County Roadgrade Dam 10-98-48, located in Iowa along the TR- Big Sioux River, is a local government-owned structure with a low hazard potential and a moderate risk assessment.
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Summary
Constructed in 1988 by Lyon Co. Engineer, this earth dam stands at a height of 31 feet and has a length of 725 feet, providing a storage capacity of 35 acre-feet. The dam serves a primary purpose of "Other" and is designed for state-regulated operations, inspections, and enforcement by the Iowa Department of Natural Resources.
Despite its uncontrolled spillway type, Lyon County Roadgrade Dam 10-98-48 has not been rated for its condition assessment and lacks emergency action plans and updated contact information. With a drainage area of 0.19 square miles and a normal storage capacity of 18 acre-feet, the dam poses a moderate risk level with no recent modifications or known structural issues. As a key infrastructure along the Big Sioux River, the dam plays a crucial role in water resource management and flood control efforts in the region.
As water resource and climate enthusiasts explore the significance of Lyon County Roadgrade Dam 10-98-48, its location in Lyon, Iowa, and its operational oversight by the state regulatory agency highlight the importance of maintaining and monitoring this critical infrastructure. With a focus on risk management and safety measures, the dam's role in protecting the surrounding community and supporting ecological balance underscores the need for continued attention and investment in water infrastructure resilience in the face of changing environmental conditions.
Year Completed |
1988 |
Dam Length |
725 |
Dam Height |
31 |
River Or Stream |
TR- BIG SIOUX RIVER |
Primary Dam Type |
Earth |
Surface Area |
2.1 |
Drainage Area |
0.19 |
Nid Storage |
35 |
Hazard Potential |
Low |
Foundations |
Soil |
Nid Height |
31 |
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.
Lyon County Roadgrade Dam 10-98-48