American Zinc Smelter Company Large Lake Dam

American Zinc Smelter Company Large Lake Dam is an earth dam located in Montgomery County, Illinois, built in 1916. It carries a Significant hazard potential classification.

About American Zinc Smelter Company Large Lake Dam

The primary purpose of American Zinc Smelter Company Large Lake Dam is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by Asarco Inc. (private). It impounds the Middle Fork Shoal Creek near Hillsboro.

The dam stands 31 feet tall and stretches 320 feet across, and has a maximum storage capacity of 300 acre-feet. Completed in 1916, the structure is over a century old.

This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. The most recent inspection on record was 07/14/2021.

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Significant HazardNot Available ConditionEmergency Action Plan: No

Location

StateIllinois
CountyMontgomery
Nearest CityHillsboro
River/StreamMiddle Fork Shoal Creek
Coordinates39.12976, -89.50501

Physical Characteristics

Dam TypeEarth
NID Height31 ft
Dam Height31 ft
Dam Length320 ft
Year Completed1916 (110 years old)

Storage & Hydraulics

NID Storage300 acre-ft
Max Storage300 acre-ft
Normal Storage184 acre-ft
Spillway TypeUncontrolled

Ownership & Safety

PurposeWater Supply
OwnerASARCO INC.
Owner TypePrivate
Hazard ClassificationSignificant
Condition AssessmentNot Available
Last Inspection07/14/2021
Emergency Action PlanNo

Identifiers

NID IDIL01063
Federal IDIL01063
More InfoState Dam Safety Program

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