Anthropogenic factors, such as land use changes, dam construction, and water extraction, significantly influence the stability and evolution of braided river channels. Land use changes, like deforestation and urban development, can alter the sediment supply to the river, either increasing sediment load due to erosion or decreasing it due to sediment trapping. This imbalance can lead to changes in channel morphology, affecting the river's braiding pattern. Dam construction and water extraction alter the river's flow regime. Reduced water flow can lead to a decrease in the river's capacity to transport sediment, causing sediment accumulation and potentially reducing the river's braiding characteristics. Conversely, sudden releases of water from dams can cause abrupt changes in channel morphology. Furthermore, pollution from agricultural runoff and urban areas can impact the water quality, affecting aquatic life and the overall health of the river ecosystem. These anthropogenic influences can significantly alter the natural dynamics of braided river channels, with wide-ranging ecological and geomorphological consequences.

The sinuosity of meandering rivers is influenced mainly by the river's slope, sediment type, and flow velocity. A lower slope tends to increase sinuosity, as the river has more energy to erode laterally rather than vertically. The type and size of sediment also play a crucial role; finer sediments are more easily eroded and deposited, promoting meander formation. Higher flow velocity increases erosion on the outer bends and deposition on the inner bends, intensifying meander curvature. This sinuosity affects river dynamics in several ways. It leads to varied flow velocities within the river, creating diverse habitats and affecting sediment transport. The slow-moving water on the inner bend allows for deposition, forming point bars, while the faster-moving water on the outer bend erodes the bank, forming river cliffs. This continuous erosion and deposition process contributes to the migration of meanders over time, affecting the river's path and the surrounding landscape. Additionally, high sinuosity can influence flood dynamics, as the meandering path increases the river's length and decreases its gradient, potentially reducing the speed of floodwaters.

Braided river channels evolve over time primarily due to variations in water flow and sediment supply. These changes can occur seasonally or as a result of longer-term climatic and environmental shifts. As water flow increases, for instance during snowmelt or heavy rains, the river's capacity to transport sediment increases, leading to the reconfiguration of channels and islands. Conversely, during periods of low flow, sediment deposition can dominate, altering channel paths. These dynamic changes can have significant implications. For one, they affect the stability of the river banks and adjacent lands, which can be crucial for infrastructure and habitats located nearby. The evolving nature of braided rivers also influences the distribution and types of habitats available for aquatic and riparian species, affecting biodiversity. Moreover, these changes impact water quality and sediment transport, which can have downstream effects on other river systems, estuaries, and even coastal regions. The dynamic morphology of braided rivers thus plays a crucial role in shaping the ecological and geomorphological character of the landscapes through which they flow.

Human activities significantly impact straight river channels, often altering their natural course and characteristics. Straightening of river channels, commonly done for agricultural, urban development, and flood control purposes, involves removing bends and meanders to create a more direct path. This artificial straightening accelerates water flow, which can lead to increased erosion downstream and potentially exacerbate flood risks. Additionally, channel straightening can disrupt the natural sediment transport processes, affecting aquatic habitats and reducing the river's ecological diversity. The construction of levees, dams, and embankments also alters the natural flow regime, sediment load, and water quality of these channels. These interventions can lead to a reduction in the channel's ability to support a diverse range of flora and fauna, affecting the broader ecosystem. Moreover, straightened channels often lack the natural meander patterns that help in nutrient distribution and sediment deposition, essential for maintaining river health and biodiversity.

Meandering river channels play a significant role in the carbon cycle, particularly in the processing and storage of organic carbon, which is crucial for environmental balance. As these rivers flow, they erode and transport organic matter from the land, including plant debris and soil organic carbon. The slow-moving water in the meanders allows for the deposition of this organic material in the floodplains and riverbeds, creating rich deposits of nutrients and carbon. These areas can act as carbon sinks, trapping and storing carbon for long periods, thereby reducing the amount of carbon dioxide released into the atmosphere. Additionally, the wetlands and marshes often associated with meandering rivers are highly productive ecosystems, sequestering large amounts of carbon through plant growth. The carbon stored in these ecosystems is significant in mitigating climate change by offsetting greenhouse gas emissions. Furthermore, the dynamic nature of meandering rivers, with their periodic flooding, can distribute organic carbon across wide areas, contributing to the fertility of the floodplains. This not only supports diverse plant and animal life but also enhances soil quality for agricultural purposes. The role of meandering rivers in the carbon cycle thus has important implications for ecosystem health, climate regulation, and sustainable land use, making their conservation and management crucial in environmental planning and policy.