Final answer:
High river levels can lead to overflow and flooding of floodplains, causing damage to infrastructure and agriculture, and leading to environmental concerns such as soil erosion.
Step-by-step explanation:
When river levels get too high, the water can overflow and result in the inundation of floodplains. These areas, often valuable for agriculture and development due to proximity to water sources, become covered in water, which can cause significant damage to infrastructure, homes, and farmlands. This could also lead to environmental degradation, such as soil erosion and increased salinity, potentially reducing the land's suitability for agriculture and disrupting the local ecosystem.
In regions such as Bangladesh, where much of the country is only a few feet above sea level, the impact of high river levels can be catastrophic, leading to extensive flooding and a high death toll, as evident from past instances where cyclone-induced storm surges resulted in massive fatalities. Moreover, the potential for increased sea levels due to climate change exacerbates the risk, threatening to submerge significant portions of the country and disrupt the food supply for a growing population.