A comparison of water balance in small basins with different landscape pattern in the upper reaches of Minjiang River

This paper studied the effects of landscape pattern (land cover types, altitude, slope, aspect, patch density and maximum patch index) on the elements of water balance (precipatation, evapotranspiration, and runoff) in two small basins (Zhenjianngguan River and Heishui River) in the upper reaches of Minjiang River during 1988-2002. Based on the spatial distribution of mean annual precipitation and evapotranspiration as well as the means annual runoff on different land cover (woodland, grassland and cropland) during 1988-2002, the relationship of landscape pattern with water balance was approached, and the result showed that in these two basin, the precipitation, evaportranspiration/precipitation ratio, and runoff/precipitation ratio had a greater difference with the altitude, slope, and aspect of woodland, and grassland had a similar hydrological effect as woodlland. On the farmland of Heishui River basin, which was distruted in dry valley, evapotranspiration was much higher than precipitation. This abnormal water balance was caused by the arid valley climate in the upper reaches of Minjiang River but not the landscape pattern of farmland, being totally different with that in Zhenjiangguan River basin.