WATER RESOURCES OF ORANGE COUNTY 41
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PERCENT OF TIME DSCHARGE SQUALED OR E XCEEDED THAT SHOWN 6__ -on~ Cw n@@ Rivinf@fand,
Figure 15. Estimated flow-duration curves for streams anid springs for
which periodic or miscellaneous discharge data are available.
throughout its range indicates a highly variable stream having little or no surface storage or ground-water storage. A curve with a flat slope throughout its range indicates the release of water from surface- or ground-water storage which tends to equalize the flow. A curve that flattens out at its lower end indicates the release of ground-water storage at low flow. A curve that flattens at its upper end indicates release of storage from lakes or swamps at high flow.
Flow-duration curves are useful for water power, water supply, and pollution studies.
Stage-duration curves (figure 16) present stage data in the same way flow-duration curves present flow data. The limitations