Abstract:
The ponds play important roles in regulating water resources in the irrigation system of hilly area.In order to reveal the characteristics and influence factors of the pond and to provide a theoretical basis for small water projects, this study chose shallow-hill region (105°38′-105°40′E, 30°08′-30°10′N), low-hill region (106°23′-106°25′E,30°05′-30°07′N) and middle-hill region (107°54′-107°56′E,30°45′-30°46′N) as sample regions, extracted the spatial distribution and hydrological characteristics of 85 ponds located in the study area by ArcGIS software based on the topographic data and land use data on a plotting scale of 1∶2000, and combined with the meteorological data ranged from 1961 to 2010, the differences and driving factors of ponds located in different microenvironments was investigated, from the perspective of water storage capacity and water resources utilization of the catchment area.The results showed: 1) The average water area (3371 m2) and landscape area ratio (171.64 m2/hm
2) of ponds in shallow-hill region was much larger than that of low-hill region (1228 m2 and 93.36 m2/hm
2) and middle-hill region (1468 m2 and 100.37 m2/hm
2), but the spatial splitting index of ponds in middle-hill region (9.50) was obviously smaller than that of shallow-hill (15.48) and low-hill region (19.27).2) The topographic index of the ponds in shallow-hill region, with an average value of 14.34, was significantly larger than that of the low-hill region (11.81) and the middle-hill region (11.35).There was remarkably positive correlation between the pond water area and topographic index in all three study region, and the pond water area exponentially changed with topographic index, but the change sensitivity was significantly different among regions.3) The irrigation guarantee capacity increased with the increasing pond water area as a whole.Nevertheless, this capacity of the ponds was significantly different in three regions.The middle-hill region and shallow-hill region shared a similar irrigation guarantee capacity indexwhich was obviously larger than that of low-hill region.Therefore, the topographical condition of hilly area was the determinant factor for the spatial distribution of ponds.The ponds water storage capacity became larger with higher topographic index as a whole and there was an approximately exponential function relationship between them under the same hilly terrain, indicating that the topographic index was an important factor affecting the pond water storage capacity.Irrigation requirement was the main driving force to the change of pond quantity and capacity caused by agricultural activity, and hilly terrain conditions and climate factors of the catchment area could indirectly influence the crop irrigation requirement, which were the primary factors affecting the quantity and quality of the ponds.