Cottonwood Creek 21-a
Cottonwood Creek 21-a is an earth dam located in Saunders County, Nebraska, built in 1983. It carries a High hazard potential classification and has a poor condition assessment.
About Cottonwood Creek 21-a
The primary purpose of Cottonwood Creek 21-a is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Lower Platte North Natural Resources District (local government). It impounds the Tr-cottonwood Creek near Malmo.
The dam stands 42 feet tall and stretches 1,100 feet across, creates a reservoir covering 33 acres, has a maximum storage capacity of 1,043 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1983, the structure is 43 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 10/17/2024.
At 42 feet, this dam is taller than 89% of dams nationwide.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Nebraska dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Nebraska |
| County | Saunders |
| Nearest City | Malmo |
| River/Stream | Tr-cottonwood Creek |
| Coordinates | 41.27849, -96.72767 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 42 ft |
| Dam Height | 37 ft |
| Dam Length | 1,100 ft |
| Year Completed | 1983 (43 years old) |
Storage & Hydraulics
| NID Storage | 1,043 acre-ft |
| Max Storage | 1,043 acre-ft |
| Normal Storage | 211 acre-ft |
| Surface Area | 33 acres |
| Drainage Area | 2 sq mi |
| Max Discharge | 7,976 cfs |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Lower Platte North Natural Resources District |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 10/17/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NE01887 |
| Federal ID | NE01887 |
| More Info | State Dam Safety Program |