Mariposa Lake Dam

TR-ALLOWAY CREEK· Jasper, Iowa· Built 1952· Earth· 25 ft tall
Low Hazard Recreation Local Government

Key Takeaway

Mariposa Lake Dam is classified as low hazard in Iowa. It was completed in 1952 and is 74 years old. Its primary use is recreation.

Physical Details

Dam Height 25 ft (taller than 19.3% in IA)
Dam Length525 ft
Dam TypeEarth
Max Storage188 acre-ft
Normal Storage112 acre-ft
Surface Area19 acres
Drainage Area1 sq mi
Max Discharge0 cfs
Year Completed1952 (74 years old)
NID IDIA01348

Safety Information

Low Hazard

No probable loss of human life and low economic/environmental losses expected.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: No
Last Inspection: May 28, 2008
State Regulated: Yes
Regulatory Agency: IOWA DNR

Ownership

Jasper County Conservation Board

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Mariposa Lake Dam?

Mariposa Lake Dam is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Mariposa Lake Dam?

Mariposa Lake Dam is owned by Jasper County Conservation Board (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Mariposa Lake Dam built?

Mariposa Lake Dam was completed in 1952, making it 74 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Mariposa Lake Dam?

Mariposa Lake Dam serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Mariposa Lake Dam?

Mariposa Lake Dam has a dam height of 25 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Mariposa Lake Dam last inspected?

Mariposa Lake Dam was last inspected on May 28, 2008. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.