Pacific Southwest Research Station

Caspar Creek Experimental Watershed Study

Annual Precipitation, Streamflow, and Sediment:

Column Description

• Year: Water year August 1 - July 31 (* except for 1963 runoff which began November 11, 1962)
• Ppt_N (mm): Annual Precipitation at raingage N408 in millimeters.
• Ppt_S (mm): Annual Precipitation at raingage S620 in millimeters.
• RO_N (mm): Annual Streamflow (runoff) at North Fork weir in millimeters.
• RO_S (mm): Annual Streamflow (runoff) at South Fork weir in millimeters.
• SuspSed_N (mT/km²): Annual Suspended Sediment discharge passing over the North Fork Weir in metric tons per square kilometer.
• SuspSed_S (mT/km²): Annual Suspended Sediment discharge passing over the South Fork Weir in metric tons per square kilometer.
• Pond_N (m³/km²): Annual volume of sediment deposited in the debris basin above the North Fork Weir in cubic meters per square kilometer. Negative numbers mean the basin survey yielded less volume than the previous year.
• Pond_S (m³/km²): Annual volume of sediment deposited in the debris basin above the South Fork Weir in cubic meters per square kilometer. Negative numbers mean the basin survey yielded less volume than the previous year.

Notes

• Values of weir pond deposition and suspended sediment for 1963 through 1976 are from Rice, Tilley, and Datzman (1979), adjusted here to a watershed area of 473.2 hectares. The original authors used 1225 ac (495.75 ha) and assumed a bulk density of 1185 kg/m³ for converting suspended sediment mass to volume. Suspended sediment was estimated from annual sediment rating curves. Since the rating curves were based primarily on rising limb samples, 1963-1975 suspended loads are very likely overestimated by a factor of 2 to 3 (Lewis, 1998).
• Suspended sediment for 1978-1998 is based on an average of 142 samples per station per year, mostly collected during high flows. Concentration was interpolated using time, stage, or turbidity during storm periods. Annual sediment rating curves were employed to estimate sediment concentrations between storms and when more than 24 hours separated the samples. These values differ somewhat from previously reported values that were based solely on sediment rating curves. These current values should be considerably more accurate.
• Weir pond deposition was derived from annual surveys of the pond from the weir up to and including the bedload delta area. Negative values appear for some low transport years and may result from either settling of sediments or measurement errors.
• * Annual Streamflow (runoff) for 1963 is calculated from November 11, 1962 through July 30, 1963.

Updated on May 21, 2007

Research contact:

• Leslie Reid