Water-related ecosystem services provided by urban green space: A case study in Yixing City (China)

With the development of urbanization, green space in urban areas has received widespread attention and become an important symbol of urban ecosystem health. Urban green space plays a positive role in water regulation and purification, but this function is often ignored by municipal authorities. Based on remote-sensing image interpretation and practical investigations in Yixing (China), this study evaluated the water regulation and purification functions performed by urban green space, using the modified Soil Conservation Service model, in conjunction with relevant experimental data. The results show that during the period 2007 to 2009, the average volume of rainfall stored by the urban green space in Yixing was 5.3 × 107 m3 yr−1, which represented more than 88% of the rainfall received. The average figures for chemical oxygen demand (CODCr), total nitrogen (TN), ammoniacal nitrogen (NH4-N), and total phosphorus (TP) in rainfall that were removed by green space during 2007 to 2009 were 233.6 × 103 kg yr−1, 70.9 × 103 kg yr−1, 12.6 × 103 kg yr−1, and 1.7 × 103 kg yr−1, respectively. Differences were found between the water regulation and purification performed by urban green space inside built-up areas and those performed outside built-up areas, which relate to the importance attached to green space in the two types of area. This research will contribute to an understanding of the role that green space plays in water regulation and purification, and in the scientific management of urban green space.