The Ecology of Tijuana Estuary, California: An Estuarine Profile

such a streamflow history, Tijuana Estuary may be
the Nation's most variable estuary. It is marinedominated
on a seasonal basis (sometimes for
several years in succession): it is occasionally
fresh during catastrophic flooding, such as
occurred in 1980.
Monthly flow volumes at Nestor (Figure 17)
show that major floods occurred in 1978 and 1980
after a 35-year period with little flow. Logtransformations
of the monthly streamflows
enhance the years of low flow and deemphasize
high-flow years. Seasonal patterns become much
clearer with such transformation, and the winterflow.
summer-drought pattern becomes obvious.
Note, however, that several entire years had zero
flow at the Nestor gage. During these times, the
estuary is presumed to have been filled entirely
Figure 15. Tijuana Estuary on January 1, 1985 (from Aerial Fotobank). Compare locations of
main river channel (Rj and agricultlrraf activities (A) with Figure 11. Traces of horse-raising
activities (H) are visible near the Border Field State Park overlook (0). Estuarine habitat
types, drawn from this photo, are mapped in Figure 3.