Mallard

California — Contra Costa County — Offstream

Location

StateCalifornia
CountyContra Costa
RiverOffstream
Coordinates38.01400, -122.03590

Physical Characteristics

NID Height30 ft
Dam Height30 ft
Dam Length11,000 ft
NID Storage3,113 acre-ft
Max Storage3,113 acre-ft
Surface Area213 acres

Safety Classification

Hazard PotentialHigh
Condition AssessmentSatisfactory
EAP StatusYes
Last InspectionFebruary 27, 2025
Inspection Frequency1

Dam Information

Year Completed1930
Primary PurposeWater Supply
Dam TypeEarth
Owner TypePublic Utility
OwnerContra Costa Water District

Location Map

About This Dam Record

Dam safety data is maintained by the Army Corps of Engineers National Inventory of Dams (NID). High-hazard dams are those where failure could cause loss of life or major property damage downstream.

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