The impact of the DGM resolution upon the parameters was also
considered and parameters were calculated for 1 m-DGM and compared
with 0.5 m-DGM results. The normalized percentage of the difference
between the 1 m results and the 0.5 m results, showed a
mean difference (0.5–1.0 m) of 0%, −31%, −10% and −10% for the
levee height, crown width, slope landside and slope waterside, respectively
for the east margin (urban side) and 0%, −20%, −4% and
−1% for the west margin (agricultural side). As expected for the
1 m case, the width of the crown is wider and slopes are steeper
due to the averaging of topography and displacement of the break
in slope due to the cell size. The 1 m case reduces the number of profiles
that do not meet USACE specifications and this could underestimate
an assessment of the risk of levee failure.