Abstract:The direct recharge area is one of the important supply places in Baotu spring region. Accompanying with the development of the city, its area is gradually reducing. By using remote sensing method, the trend of urban development in Jinan over the past 60 years have been intetpreted. The influence on the variation characteristics of the direct recharge area and the infiltration function of the strong leakage small watershed have been analyzed and revealed. The Influence of the reduction of the direct recharge area on spring protection has been calculated by the rainfall infiltration coefficient of the atmosphere. As showed by the results, from 1954 to 2015, the urban development in Ji'nan has experienced three stages as gradual growth, rapid growth and explosive growth. As a result, the direct recharge area of spring has reduced 130km2, and accounts for about 29% of the total area. In the direct recharge area, strong leakage basins suffered damage to varying degrees, 6 leakage functions are completely lost, 9 leakage functions are partially lost, and only 9 leakage functions are preserved in good condition. As a direct result, the infiltration recharge of spring water is reduced by about 9.7104m3/d(measured by the average annual rainfall of 648mm). The ecological function of the direct recharge area needs to be protected and repaired urgently. It is necessary to manage the mountain, water, forest, soil and grass in the small watershed as a whole, strengthen the systematic protection and restoration of the local water cycle of the hillside, the foot of the mountain and the valley in the small watershed, and gradually restore the replenishment capacity of the spring water.
