Sprague Lower Reservoir Reservoir Report

Last Updated: December 6, 2025

Sprague Lower Reservoir, also known as Lake Wionkheige, is a private water resource located in Smithfield, Rhode Island.


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Summary

Built in 1822, this reservoir spans 30 acres and has a storage capacity of 255 acre-feet. Its primary purpose is for recreation, offering a serene environment for fishing, boating, and other outdoor activities. The reservoir is situated on the Stillwater River, a tributary that enhances the natural beauty of the area.

Despite its picturesque setting, Sprague Lower Reservoir is facing challenges in terms of maintenance and safety. With a high hazard potential and a poor condition assessment, there are concerns about its structural integrity. The last inspection in May 2017 revealed maintenance issues, prompting the need for regular assessments and potential risk management measures. It is crucial for authorities to prioritize the upkeep of this reservoir to ensure the safety of both the environment and recreational enthusiasts.

Water resource and climate enthusiasts can appreciate the historical significance and ecological value of Sprague Lower Reservoir. As a key player in the water infrastructure of Rhode Island, this reservoir serves as a vital resource for both local communities and wildlife. Efforts to address its maintenance and safety concerns are essential to preserve this natural gem and continue to provide a recreational haven for future generations to enjoy.

Year Completed

1822

Dam Length

250

Dam Height

15

River Or Stream

STILLWATER RIVER-TRIB

Surface Area

30

Hydraulic Height

14

Drainage Area

1

Nid Storage

255

Structural Height

19

Hazard Potential

High

Nid Height

19
       
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.