Water Education Foundation.
"Suisun Slough is under the influence of tides. The most severe flooding along this waterway would result when very high tides and a large volume of stream outflow occur coincidently. In Suisun City, restrictive outlets into slough areas cause floodflows to pond in low-lying areas, and high tides may delay drainage for several days. Flooding occurred in Suisun City in 1940, 1950, 1955, 1963, 1966, 1967, 1969, 1970, and 1973. Extensive flooding along State Highway 12 occurred in December 1955. Floodwater rose to waist depth in a residential development when high tides slowed drainage. In January 1967, floodwater covered one-third of the streets, and was approximately 2 feet deep in the southern part of town. Flooding from Pennsylvania Avenue Creek and Union Avenue Creek had a recurrence interval of 15 years for the 1967 flood. A high tide and overflow from Laurel Creek and Union Avenue Creek caused flooding in January 1970." Flood Insurance Study.
"A flood damage survey was made during the January 1970 flood, but streamflow measurements and high-water marks are available for only the 1973 flood. Examples of flooding in the project area are shown in the photos. Newspaper articles, photographs and descriptions by local residents for the other flood years indicate substantial losses to residences, businesses, crops, and county roads. These floods caused many homes to be evacuated, disrupted community activities, and endangered the health and safety of residents and those involved in rescue operations." Fairfield Vicinity Streams.
"Those of you who have lived here since the 1970s or earlier may remember what the state-named streets in Fairfield looked like after a heavy rain and, if I remember correctly, a high tide. There was a tidal incursion on streets that have long since been redone and the flooding problem totally mitigated." Bud Stevenson, Solano Daily Republic.
It has been suggested in previous articles that the Zodiac Killer may have resided near the payphone at Springs Road and Tuolumne Street, but we know that two letters were mailed from Fairfield to the San Francisco Chronicle on December 7th 1969, and to the San Francisco Examiner on December 16th 1969. If these were genuine Zodiac letters, then there is a possibility that he may have been a resident of Suisun City or Fairfield for the duration of the 7th to 16th of December and mailed his letters from this location. Was he a resident of this area beyond December 16th 1969, or did he reside here permanently? The Bay Area murderer may have had two residences, a vacation home, lockup or a business in this region of Solano County.
Just a matter of weeks after the final Fairfield letter, floods in Suisun City/Fairfield, "from Laurel Creek and Union Avenue Creek caused flooding in January 1970" resulting in the evacuation of many "residences and businesses" in the area. The Zodiac Killer then wrote to the San Francisco Chronicle in April, stating "that my bus bomb was a dud. I was swamped out by the rain we had a while back." But was he telling the truth?
# The population of Suisun City was only 2,917 in 1970.
# The population of Fairfield was 44,146 in 1970.