It appears that the lake was created by damming a small creek that flows from the east.
Oakland Tribune - Fri - July 20, 1951:
An Alameda County coroner's jury today recommended that Tyson Lake, an unused reservoir here, be either drained or properly fenced to prevent further accidents.
Their recommendations followed an inquest into the death of James Richards, 17, of 2429 Hannah Street, who drowned while swimming in the lake late Monday.
Oakland Tribune - Sat - July 12, 1952:
With the recovery of the body of the second drowning victim within a year, Piedmont city officials began consideration today of measures either to drain or fence off Tyson Lake.
Navy Diver Bob Kinneavy, stationed aboard the carried USS Antietam, recovered the body of Donald Stracner, 19, yesterday morning. Stracner, who lived at 2515 13th Avenue drowned Tuesday night while swimming with two companions.
Oakland Tribune - Fri - Aug. 8, 1952
Oakland Tribune –
Tue – Jun. 5, 1956
Oakland Tribune - Fri - Feb. 21, 1958
Oakland Tribune - Tues - Dec. 18, 1956:
The Board of Education today prepared an option agreement under which it may buy two lots adjoining a proposed new elementary school site at Hampton Road and LaSalle Ave.
...The proposed school site would be on the property already owned by the Board of Education, but construction is being held up pending repairs to the Tyson Lake Dam, now considered unsafe, located directly above the land.
A property owners' committee including Timothy Bedford, Shubert S. Inch, Paul B. Richards and Harry L. Price determined the dam outlet should be repaired and a new spillway built 10 feet below the present spillway. The committee will discuss the repairs with the school board Jan. 7.
Oakland Tribune - Wed - Apr. 16, 1958:
The dam, which holds back 25 acre feet of water, is above the intersection of Hampton Road and La Salle Ave. It was declared "potentially unsafe" by state engineers in 1940.
In a letter to the city council, a six-man committee of property owners adjacent to the lake said it believed funds could be raised to construct a new spillway and lower the lake 10 feet.
...Present condition of the dam has made it impossible for the Piedmont Unified School District to plan construction of an elementary school on district owned property at Hampton Road and La Salle Avenue.
Oakland Tribune - Wed - Jan. 7, 1959:
A 20 year campaign to bring Tyson Lake Dam within safety regulations is over today.
City officials have been notified by W. A. Brown, principal engineer of dams for the State Department of Water Resources, that the damn now meets requirements.
The dam was declare "potentially unsafe" by state engineers 20 years ago, A $6,000 reconstruction job was started last August with funds provided by residents of the area.