proportionality of sediment load to flow and slope indicated by these results is consistent with current

understanding of rill erosion processes. Large and increasing dimensionless FT/C sediment load ratios

with soil moisture highlight the primary role of FT in rill erosion processes that increases with soil

moisture.

We measured and characterized cross sections of the rills at 0.3*L *(24 cm) and 0.7*L *(55 cm) above

the outlet both before and after the flow event. The two norms used to measure cross-sectional change

were *L*2, the root-mean-square of the change in bed elevation resulting from the flow, and *L*inf, the

maximum bed elevation change at a point in each cross section. These measures are particular to these

specific locations, and might be influenced by local effects that are not representative of the complete

reach. To more fully characterize the extent of erosion in each bin, other local measures were obtained to

supplement the detailed cross-section measurements. Maximum channel width and maximum channel

depth at every 0.1*L *were measured at the conclusion of each experiment and averages are presented here.

flow condition by slope and soil moisture series. Corresponding *L*inf results for this same cross section are

given in Figure 14. These same measures at 0.7*L *are given in Figures 15 and 16, respectively. Our initial

observation is that both measures are providing very similar information concerning cross-sectional

change. The norms indicate very small changes in the controls for both the mid and high soil moisture

series, with all norms less than 2.2 and 1 cm, respectively, for these series. The norms for the low soil

moisture series in the C bins are also generally small, with *L*2 < 2.5 cm and *L*inf < 3.6 cm. The upper

bound on these C norms decreased as soil moisture increased, indicating generally greater erosion

applied flow for the low and mid soil moisture series, and indicate generally enhanced erosion with slope.

At high soil moisture the slope dependence of cross-sectional change is again clear, but dependence on

flow rate is not apparent. The *L*2 and *L*inf FT/C ratios generally increase with soil moisture, but display no

clear dependence on flow or slope. Anomalously high ratios at 0.7*L *for the low moisture, high flow, and

low and high slope experiments indicate excessive erosion in that part of the FT bin relative to the same

location of the C bin. The ratios of the high soil moisture series are generally high, a result of very minor

erosion in the C bins. Greater relative erosion of the C bins in the high flow, high moisture experiments

produced the smallest ratios of the group.

Tables 7 and 8 give overall and group-averaged norms and their FT/C ratios for 0.3*L *and 0.7*L*,

respectively. *L*2 and *L*inf FT/C ratios for the overall experiment are equal (2.81) at 0.3*L*, and nearly equal

(4.94, 4.56) at 0.7*L*, with values much greater than 1 indicating a primary effect of the FT cycle on rill

erosion. At 0.3*L *the series-averaged ratios of the *L*2 and *L*inf measures are approximately equal for each

moisture series, and increase dramatically with soil moisture. This increase is due largely to significant

decreases in the C measures with increasing soil moisture. Rough equality of *L*2 and *L*inf FT/C ratios also

occurred at 0.7*L*, but the low soil moisture ratios were much larger and comparable to those at high

moisture. The high ratios at high moisture are again due to greatly decreased measures in the C bins.

Both norms show minor increases for increasing slope groupings at both locations, and corresponding

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