Geographical environment of Zhangye National Wetland Park

The planning area of Zhangye National Wetland Park is located in the front of Qilian Mountain alluvial fan in the middle reaches of Heihe River, and the phreatic overflow area of Heihe ancient river and floodplain. It is a composite wetland ecosystem composed of natural wetlands such as rivers, herbaceous swamps and wet meadows and artificial wetlands such as lakes, ponds and ditches. Wetland types are diverse, and the original ecological characteristics are outstanding. According to written records, the northern suburb of Zhangye City has been known as "the cloud water town in the north of Ganzhou" since ancient times. From the urban area to the northern suburbs, there are lakes everywhere, and hundreds of springs gush out, forming a wetland system of more than 30 thousand mu.

The planning area is high in the south and low in the north, with a natural drop of 20m (1467— 1445). In addition to the supplementary water source of Heihe River and Runoff New River, groundwater seepage is its main water source. There are 12202 natural springs, 3 channels and 17 artificial drains in the northern suburb wetland, and the wetland plants are densely distributed. The wetland vegetation in the planning area is rich, and the emergent plants, floating plants, submerged plants, hygrophytes and halophytes are embedded with terrestrial trees and shrubs, grassland vegetation and desert vegetation. The formed western oasis ecosystem is typical in the arid area of northwest China, unique in the world, and has special protection value. The total planned area of Zhangye National Wetland Park is 6 1622 mu, including 25,995 mu of wetland area, irrigated farmland 1776 1 mu (paddy field 1722 mu, 6,834 mu of wasteland, 205 mu of newly opened wasteland) and woodland 351mu. The soil types in the planning area mainly include meadow soil, fluvo-aquic soil, river silt, meadow saline soil and swamp soil. Most of them are lacustrine sediments, yellowish brown and grayish green muddy soil, with yellow clay or humus-rich muddy layer scattered on the surface. There is enough water in the soil, and the activity of aerobic microorganisms is blocked, which is not conducive to the mineralization of organic matter, affects the direction and process of soil formation, and forms natural soil mainly composed of meadow soil and cultivated soil mainly composed of tidal soil.