Kaifeng is located in northeastern Henan Province, downstream of the Yellow River, in the heart of the eastern Henan Plain. It borders Shangqiu to the east, Zhengzhou to the west, Xuchang to the south, and the Yellow River to the north. With a strategic geographical location, Kaifeng has historically been an important transportation hub and economic center in China. The city’s terrain is predominantly flat, as it lies on the Yellow River's alluvial plain, with an average elevation of around 70 to 80 meters, making it a low-lying area.

Kaifeng experiences a temperate monsoon climate, characterized by distinct seasons: hot, rainy summers and cold, dry winters. While the Yellow River has provided abundant water resources, Kaifeng's low elevation has long exposed it to flood risks. Frequent changes in the Yellow River’s course and flooding have profoundly shaped Kaifeng’s topography and geographical features.

Formation of the Yellow River Alluvial Plain

The Yellow River carries a substantial amount of sediment each year. When the river’s flow slows down, sediment deposits form vast alluvial plains. The eastern Henan Plain, where Kaifeng is situated, is a typical example of such a plain. The fertile soil here supports agricultural production, but the thick sediment layers also make the terrain low and flat, exacerbating Kaifeng’s vulnerability to flooding.

Low Terrain and Flood Risks 

Due to its low-lying topography, Kaifeng is particularly vulnerable to flooding when the Yellow River’s water level surpasses that of the city. Any breach in the river’s levees can easily lead to severe flooding in Kaifeng. The city has faced numerous catastrophic floods in its history, making flood control a persistent focus across various dynasties. In modern times, the construction of levees and water diversion projects has alleviated some of the flooding risks.

Changes in the Yellow River’s Course and City Topography  

Historically, the Yellow River’s frequent course changes have significantly altered Kaifeng’s landscape. For instance, major river course changes in 602 AD and 1048 AD transformed Kaifeng’s geographical environment. Such shifts not only led to soil erosion but also created valleys, marshes, and wetlands around Kaifeng, impacting land use and urban development.

Groundwater Resources and Springs  

The Yellow River has influenced Kaifeng’s groundwater resources. The city’s shallow water table is fed by the Yellow River system, creating springs in some suburban areas. In ancient times, many of Kaifeng’s wells drew water from this source, with their levels directly affected by the Yellow River’s fluctuations between wet and dry periods. While the Yellow River supports water resource development in Kaifeng, effective groundwater management is essential to prevent declines in water levels during dry periods.

Wetlands and Biodiversity

The Yellow River has contributed to the development of wetland ecosystems along its banks, nurturing diverse flora and fauna. Wetlands in Kaifeng are primarily found along the Yellow River’s edge and in adjacent low-lying areas. These wetlands are vital to the local ecosystem and also serve as buffers against flooding. Reed marshes, shallow ponds, and other wetland features provide habitats for birds and breeding grounds for fish, contributing to high biodiversity.

Sandy Soil and Wind Erosion Issues  

The Yellow River’s heavy sediment load has left sandy soils across the alluvial plain near Kaifeng, making the soil texture loose. Following flooding, the deposited silt results in coarse soil particles that are vulnerable to wind erosion. During winter and spring, wind erosion can lead to sandstorms, posing challenges for agriculture and the environment. Local measures such as afforestation and the establishment of shelterbelts around farmland have helped mitigate this issue over time.