WATER RESOURCES OF ORANGE COUNTY 39
TABLE 7. SITES WHERE MISCELLANEOUS SURFACE-WATER DATA HAVE BEEN COLLECTED.
No. of
chemical
Station no. Station analyses
48 Bonnet Creek near Vineland 3 49 Christmas Creek near Christmas 1 50 Howell Creek near Maitland 2 51 Jim Branch near Narcoossee 2 52 Little Wekiva River near Forest City 1 53 Mills Creek near Chuluota 1 54 Reedy Creek near Vineland 2
55 Roberts Branch near Bithlo
56 Rock Springs near Apopka 7 57 Second Creek near Christmas 1
58 Settlement Creek near Christmas
59 Taylor Creek near Cocoa 1
60 Tootoosahatchee Creek near Christmas
61 Wekiva Springs near Apopka 5 62 Witherington Spring near Apopka 1
Table 8 gives the ranges in quality of surface water at selected sites in and near the county.
Many of the data on surface water are presented as flowduration curves, stage-duration curves, flood-frequency curves, and low-flow frequency curves.
Flow-duration curves (figures 14 and 15) are cumulative frequency curves that show the per cent of time specified discharges were equaled or exceeded during a given period. In a strict sense flow-duration curves apply only to the period in which the data used to develop the curve were obtained. Flow-duration curves are useful for predicting future flow distribution only if the data used represent the long-term distribution and if the climate and basin characteristics remain unaltered. Flow-duration curves based on less than 5 years of record were adjusted on the basis of concurrent records at a nearby site having a long-term record. The curves were thus made more representative of the longer periods. Flow-duration curves were estimated for the sites having only a few periodic observations by correlating these observations with concurrent data for nearby stations where data were complete.
The shape of a flow-duration curve indicates the physical characteristics of the basin it represents. A curve that is steep