Pony Creek Watershed Site 9 Reservoir Report

Last Updated: December 14, 2025

Pony Creek Watershed Site 9 is a significant water resource site located in Mills, Iowa, managed by the local government with oversight from the Iowa Department of Natural Resources.


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Summary

This earth dam structure, designed by USDA NRCS and completed in 1967, serves multiple purposes including fire protection, stock, small fish pond, and flood risk reduction. The dam has a height of 60 feet, a length of 763 feet, and a storage capacity of 433 acre-feet, providing essential water management functions for the area.

With a low hazard potential and a moderate risk assessment rating, Pony Creek Watershed Site 9 plays a crucial role in mitigating flood risks and ensuring water availability for various purposes in the Pacific Junction area. The dam is inspected periodically, with the last inspection conducted in September 2003. While the condition assessment is not rated, the structure meets regulatory requirements and is equipped with an uncontrolled spillway, emphasizing its importance in maintaining water quality and quantity in the region.

As an essential infrastructure for water resource management, Pony Creek Watershed Site 9 highlights the collaborative efforts between local government, federal agencies, and conservation services in ensuring the sustainability of water sources in Iowa. With its strategic location along the TR-Pony Creek, this site serves as a vital component in the overall watershed management plan, contributing to the resilience of the ecosystem and the community against potential water-related challenges.

Year Completed

1967

Dam Length

763

Dam Height

60

River Or Stream

TR-PONY CREEK

Primary Dam Type

Earth

Surface Area

21.4

Drainage Area

0.97

Nid Storage

433

Hazard Potential

Low

Foundations

Soil

Nid Height

60
       
Seasonal Comparison

Weather Forecast

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. 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

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, 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.