3.2 Development rate of ephemeral gully morphological features
In 2009, 2012, 2018, and 2021, ephemeral gully lengths ranged from
7.00–209.50, 5.00–228.00, 5.00–230.00, and 5.00–209.50 m (average
48.39, 46.58, 45.75, and 45.84 m) (Table 3), with total ephemeral gully
lengths of 55.79, 95.26, 110.40, and 105.98 km and densities of 1.66,
2.84, 3.59, and 3.15 km km–2, respectively, and
development rates of 1.66 m y–1 (length) and 0.12 km
km–2 y–1 (density). From 2009 to
2021, ephemeral gully width ranged from 0.50 to 2.50 m, with more than
99% between 0.50 and 1.50 m and an average width development rate of
0.04 m y–1. The proportion of ephemeral gully widths
2.00–2.50 m decreased from 0.67% in 2009 to 0.05% in 2021. In 2009,
2012, 2018, and 2021, ephemeral gully area ranged from 6.50–230.71,
4.64–246.86, 4.64–230.00, and 5.36–209.50 m2(average 49.12, 47.34, 46.05, and 46.36 m2), total
area was 0.0566, 0.0968, 0.1111, and 0.1072 km2, and
dissection degree was 0.17%, 0.29%, 0.33%, and 0.32%, respectively,
with development rates of 4,213.39 m2y–1 (total area) and 0.0125% y–1(dissection degree). This study found that the development rate of all
ephemeral gully morphological parameters gradually decreased over time.
Table 3 Ephemeral gully morphological features from 2009 to 2021 in the
Zhoutungou watershed.