Porter Reservoir Dam Reservoir Report

Last Updated: December 5, 2025

Porter Reservoir Dam, located in New Castle, Delaware, was completed in 1909 and serves as a vital water supply source for the area.


°F

°F

mph

Wind

%

Humidity

Summary

Owned by the local government and regulated by the Delaware Department of Natural Resources and Environmental Control (DNREC), this gravity dam stands at a height of 11.8 feet and has a normal storage capacity of 103.38 acre-feet. Despite being classified as having a high hazard potential, the dam is currently in fair condition as of its last assessment in 2000.

With a surface area of 6.4 acres and a drainage area of only 0.01 square miles, Porter Reservoir Dam plays a crucial role in managing water resources for the surrounding community. Although it lacks a spillway, the dam has a maximum discharge capacity of 18 cubic feet per second, ensuring effective water control during peak flow periods. Despite its age, the dam continues to meet state regulatory standards, with regular inspections and enforcement measures in place to ensure its structural integrity and public safety.

For water resource and climate enthusiasts, Porter Reservoir Dam represents a historic engineering marvel that continues to provide essential water supply services to the residents of Wilmington. With its significant storage capacity and high hazard potential, the dam serves as a reminder of the importance of maintaining and managing critical infrastructure to ensure the sustainability and resilience of water resources in the face of changing climate conditions. As efforts to mitigate risks and improve infrastructure continue, Porter Reservoir Dam remains a key component of the region's water management system, highlighting the intersection of water resource management and climate adaptation in a rapidly evolving environment.

Year Completed

1909

Dam Length

2160

Dam Height

11.8

River Or Stream

MATSON RUN-OS

Primary Dam Type

Gravity

Surface Area

6.4

Drainage Area

0.01

Nid Storage

114

Outlet Gates

None

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

12
       
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.