Wiggins Mill Pond Dam Reservoir Report

Last Updated: December 5, 2025

Wiggins Mill Pond Dam, also known as Harmons Mill Pond, is a private dam located in New Castle, Delaware, on the Appoquinimink River.


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Summary

Built in 1965, this gravity dam stands at a height of 16.64 feet and has a length of 350 feet. The dam serves primarily for recreation purposes, providing a storage capacity of 201 acre-feet and a surface area of 2.24 acres.

Although not regulated by the state, Wiggins Mill Pond Dam has a high hazard potential and a moderate risk assessment rating. With a maximum discharge of 1917 cubic feet per second and an uncontrolled spillway type, the dam poses potential risks to the surrounding area. Despite its condition being listed as "Not Rated", the dam's risk management measures and emergency action plan status remain unclear.

Water resource and climate enthusiasts may find Wiggins Mill Pond Dam an intriguing subject for further investigation, given its historical significance and potential impact on the local ecosystem. As a private structure with no state jurisdiction, the dam's maintenance and safety protocols raise questions about its long-term sustainability and resilience in the face of changing environmental conditions.

Year Completed

1965

Dam Length

350

Dam Height

16.64

River Or Stream

APPOQUINIMINK RIVER-TR

Primary Dam Type

Gravity

Surface Area

2.24

Drainage Area

4.58

Nid Storage

201

Outlet Gates

None

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

17
       
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.