{'fraction_non_alphanumeric': 0.023680930619027835, 'fraction_numerical': 0.0008309098462816784, 'mean_word_length': 5.633608815426998, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Drainage reorganization induces deviations in the scaling between valley width and drainage area

Abstract. The width of valleys and channels affects the hydrology, ecology,
and geomorphic functionality of drainage networks. In many studies, the
width of valleys and/or channels (W) is estimated as a power-law function of
the drainage area (A), W=kcAd. However, in fluvial systems
that experience drainage reorganization, abrupt changes in drainage area
distribution can result in valley or channel widths that are disproportional
to their drainage areas. Such disproportionality may be more distinguished
in valleys than in channels due to a longer adjustment timescale for
valleys. Therefore, the valley width–area scaling in reorganized drainages
is expected to deviate from that of drainages that did not experience
reorganization. To explore the effect of reorganization on valley width–drainage area
scaling, we studied 12 valley sections in the Negev desert, Israel,
categorized into undisturbed, beheaded, and reversed valleys. We found that
the values of the drainage area exponents, d, are lower in the beheaded
valleys relative to undisturbed valleys but remain positive. Reversed
valleys, in contrast, are characterized by negative d exponents, indicating
valley narrowing with increasing drainage area. In the reversed category, we
also explored the independent effect of channel slope (S) through the
equation W=kbAbSc, which yielded
negative and overall similar values for b and c. A detailed study in one reversed valley section shows that the valley
narrows downstream, whereas the channel widens, suggesting that, as
hypothesized, the channel width adjusts faster to post-reorganization
drainage area distribution. The adjusted narrow channel dictates the width
of formative flows in the reversed valley, which contrasts with the meaningfully
wider formative flows of the beheaded valley across the divide. This
difference results in a step change in the unit stream power between the
reversed and beheaded channels, potentially leading to a “width feedback”
that promotes ongoing divide migration and reorganization. Our findings demonstrate that valley width–area scaling is a potential tool
for identifying landscapes influenced by drainage reorganization. Accounting
for reorganization-specific scaling can improve estimations of erosion rate
distributions in reorganized landscapes.
