Iatt Lake Dam Reservoir Report

Last Updated: December 9, 2025

Iatt Lake Dam, located in Colfax, Louisiana, was completed in 1956 by the LA Department of Public Works and stands as a significant state-regulated structure along Bayou Rigolete.


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Summary

This earthen dam with buttress and stone core types serves multiple purposes, including recreation and water resource management. With a height of 36 feet and a storage capacity of 167,000 acre-feet, it covers a surface area of 7,100 acres and drains a watershed of 242 square miles.

The dam's spillway, 250 feet wide, is uncontrolled, allowing for a maximum discharge of 12,128 cubic feet per second. Despite its satisfactory condition assessment as of June 2020, the dam poses a high hazard potential. Emergency action plans are in place, and regular inspections ensure its safety. While the risk assessment indicates a moderate level, ongoing risk management measures remain unspecified. Positioned within the Vicksburg District and overseen by the LA DOTD, Iatt Lake Dam stands as both a vital water management structure and a recreational asset for the community.

Year Completed

1956

Dam Length

5310

Dam Height

36

River Or Stream

BAYOU RIGOLETTE

Primary Dam Type

Earth

Surface Area

7100

Hydraulic Height

30

Drainage Area

242

Nid Storage

167000

Structural Height

36

Outlet Gates

Slide (sluice gate)

Hazard Potential

High

Foundations

Soil

Nid Height

36
       
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.