SOFIA - Water Flow and Nutrient Flux from Five Estuarine Rivers - Computation of Discharge

Discharge was computed using both a water depth to cross-sectional area relation and an index-to-mean velocity relation. Water depth to cross-sectional area relations were developed using 2nd-order polynomial equations. Velocity relations were developed using linear regression analysis of measured data. Random and systematic instantaneous discharge errors were evaluated.

Cross-Sectional Area Relation

River station cross-section bathymetry was measured using a 200 kHz recording fathometer. Cross-section elevation data not measured directly with the fathometer were measured using stadia rod and laser distance measurements. Water-level data were used with cross-section bathymetry data to determine cross-sectional area for any given water level. The water-level to cross-sectional area relation equations are shown in table 2.

Station name	Water-depth-to-cross-sectional area equation
Table 2. Southwest coast station cross-sectional area regression equations. [Area in square feet; depth, water level in feet]
Lostmans Creek	Area = 0.19 * depth² + 277.2 * depth +10.2
Broad River	Area = 0.28 * depth² + 185.9 * depth + 256.1
Harney River	Area = 2.20 * depth² + 365.0 * depth + 1527.8
Shark River	Area = 0.35 * depth² + 423.9 * depth + 901.6
North River	Area = 0.37 * depth² + 246.6 * depth + 5.9

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Last updated: 31 March, 2005 @ 01:16 PM (KP)