Channel incision in rivers can cause marked ecological and economic damages. This phenomenon is abundant and generally well documented along impacted streams in the loess hills adjacent to the Lower Mississippi River valley. Bayou Pierre, an ecologically important small tributary of the Mississippi River, is currently incising but causes are not well understood. In this study, we examine diverse data sources to: (1) reconstruct a history of erosional stimuli and possible origins and (2) examine effects of contemporary controls. Review of long‐term planform and land use data for the Mississippi River revealed episodic foreshortening events followed by episodic deforestation and reforestation. Hydrologic data suggest an increase in rainfall over the last few decades. Estimates of knickpoint retreat place origins prior to Mississippi River channel straightening (1929–1944). Planform analysis in three focal reaches of Bayou Pierre demonstrates slow change prior to 1982, but accelerated changes after those periods. Mean rainfall and 3‐day storm intensity correlate to some planform changes; however, the storm of 1983 may be a better explanation of sudden planform change. We found some evidence of potential internal feedback loops in patterns of bar growth. Together, our analyses provide a synthesis of stimuli experienced by Bayou Pierre over the last ~200 years and suggest both channel migration events before straightening of the Mississippi River and more recent hydrologic events have influenced patterns of geomorphic change in Bayou Pierre.

中文翻译：

---

密西西比州皮埃尔河沿岸的小点退缩和形态演变的历史和当代驱动因素

河流中的河道切割会造成显着的生态和经济损失。这种现象在密西西比河下游河谷附近的黄土丘陵中受影响的溪流中非常普遍，并且通常都有详细记录。密西西比河的一条具有重要生态意义的小支流皮埃尔河口目前正在下切，但原因尚不清楚。在这项研究中，我们检查了不同的数据源，以：（1）重建侵蚀刺激的历史和可能的起源；（2）检查当代控制的效果。对密西西比河长期规划和土地利用数据的审查揭示了间歇性的缩短事件，随后是间歇性的森林砍伐和重新造林。水文数据表明过去几十年降雨量有所增加。对拐点退缩的估计起源于密西西比河河道矫直之前（1929-1944 年）。对 Bayou Pierre 三个焦点河段的平面分析表明，1982 年之前变化缓慢，但在这些时期之后变化加速。平均降雨量和 3 天风暴强度与一些平面变化相关；然而，1983 年的风暴可能是对平面形状突然变化的更好解释。我们发现了一些证据，表明金条生长模式中存在潜在的内部反馈循环。总之，我们的分析提供了皮埃尔河口在过去约 200 年中经历的刺激的综合，并表明密西西比河变直之前的河道迁移事件和最近的水文事件都影响了皮埃尔河口的地貌变化模式。