WATER RESOURCES OF ORANGE COUNTY 59
and June 20 to July 31, 1963. This would be about 15 percent of the time in the 10-year period of record.
A spectrograph analysis for minor elements was made on water collected from the St. Johns River near Cocoa at low flow on May 11, 1962. The results in micrograms per liter are given in Table 10. Micrograms per liter can be converted to ppm by dividing by 1,000. The symbol > indicates that the concentrations are less than the values shown which are the lower limits of detection.
Small Tributaries Draining To East
The eastern part of the county between the main stem of the St. Johns River and the Econlockhatchee River, amounting to about 180 square miles drains to the St. Johns River by numerous small tributaries. Table 7 shows data pertinent to these tributaries. Figure 26 shows profiles of the beds of several of the small tributaries.
The hydrologic characteristics of all these small streams are probably similar to those of Jim Creek. Curve 3 (fig. 15) is the estimated flow-duration curve for Jim Creek near Christmas (station 24). The relative straightness of this curve indicates the small amount of storage both on the surface and in the ground in this area. Its steepness is indicative of the extreme variability associated with steep bed slope and absence of storage. As indicated by the curve, streams in this area are dry about 20 percent of the time. The average flow at station 24 is estimated to be 26 cfs or
TABLE 10. MINOR ELEMENTS IN WATER FROM ST. JOHNS RIVER NEAR COCOA ON MAY 11, 1962.
(Quantitative results in micrograms per liter. The symbol < indicates
concentrations are less than the values shown which are the lower limits of detection)
Aluminum 66 Germanium < 0.29 Beryllium < 0.57 Manganese < 1.4 Bismuth < 0.29 Molybdenum < 1.4 Cadmium ( 1.4 Nickel 1.9 Cobalt < 1.4 Lead < 1.4 Chromium < 1.4 Titanium < 5.7 Copper < 1.4 Vanadium 0.54 Iron 5.1 Zinc < 5.7
Gallium < 5.7