ARS | Publication request: SPATIAL CHARACTERISTICS OF THUNDERSTORM RAINFALL FIELDS AND THEIR RELATIONSHIP TO RUNOFF

Submitted to: Trans American Geophysical Union
Publication Type: Proceedings
Publication Acceptance Date: November 12, 1996
Publication Date: N/A

Technical Abstract: Two methods of interpolation (kriging and multiquadric) were used to estimate precipitation values and geometric storm characteristics using 91 raingages, over the 150 square kilometer USDA-ARS Walnut Gulch Experimental Watershed with similar results. The multiquadric method was judged superior for its ease of use with large data sets. Several geometric cmeasures were then computed from interpolated surfaces for roughly 300 summer storms occurring over a 17 year period and correlated with basin runoff. The majority of the storms cover the entire watershed and thus areal coverage of storm is not a good indicator of the runoff produced. The areal coverage of the storm core (10 minute intensity greater than 25 mm/hr) was found to be more important and the storm core volume was found to the most important variable in runoff prediction. Also the position of the storm core relative to the watershed outlet becomes more important as the catchment size increases. This observation indicates the importance of interaction of catchment size/shape with the spatial storm structure in runoff generation. Antecedent watershed wetness did not appreciably contribute to runoff explanation.