郑州市土地利用/覆被变化模拟预测及其水源涵养量计算评估

Prediction of land use/cover change and evaluation of water conservation function in Zhengzhou City

【目的】为研究郑州市未来土地利用/覆被变化及其水源涵养量,综合自然地理、社会经济、降水和蒸散发等数据,【方法】采用Dyna-CLUE模型模拟了郑州市2020年土地利用/覆被变化,通过与实际土地利用图进行比较验证,证明该模型可用。设置不同情景,同时考虑了多种土地利用/覆被类型的未来变化趋势和经济效益最大化,进而模拟了2025年、2030年土地利用/覆被变化。运用水量平衡法,结合土地利用变化计算评估水源涵养量。【结果】结果表明:2020年总水源涵养量为3.31×108m3,空间分布特征为西南高,东北低,林草区高,非林草区低。在未来土地利用变化情况下,不同土地类型对应的水源涵量随着该土地面积的增加而增加,减少而减少。“现状发展”情景下总水源涵养量逐年下降,到2030年总体下降0.21×108m3,主要集中在中部和中西部地区;“规划发展”情景下总水源涵养量到2025年下降0.03×108m3,到2030年增加0.01×108m3,变化主要集中在郑州市西南部地区。郑州市耕地面积大幅变化和林草地单位面积水源涵养量较大是影响水源涵养量变化的主要因素;林草地水源涵养能力最高,郑州市占土地面积20%左右的林草地提供了40%的水源涵养量。【结论】研究成果将为郑州市未来的土地利用规划、生态系统水源涵养保护提供科学依据。

[Objective] In order to study the future land use/cover change and water conservation in Zhengzhou, [Methods]the Dyna-CLUE model was used to simulate the 2020 land use/cover change in Zhengzhou based on the data of physical geography, social economy, precipitation and evapotranspiration. The model was validated by comparison with the actual land use map. Different scenarios were set, and the future change trend and economic benefit maximization of various land use/cover types were considered at the same time, and then the land use/cover changes in 2025 and 2030 were simulated. The water balance method and land use change were used to calculate and evaluate water conservation. [Results] The results show that the total water conservation in 2020 was 3.31×10~8 m~3, and the spatial distribution characteristics were high in southwest and low in northeast, high in forest and grassland areas and low in non-forest and grassland areas. In the case of land use change in the future, water conservation corresponding to different land types will increase and decrease with the increase of the land area. Under the “status quo development” scenario, the total water conservation decreased year by year, with an overall decrease of 0.21×10~8 m~3 by 2030, mainly concentrated in the central and central regions. Under the scenario of “planned development”, the total water conservation will decrease by 0.03×10~8 m~3 in 2025 and increase by 0.01×10~8m~3 in 2030, with the change mainly concentrated in the southwest of Zhengzhou. The main factors affecting the change of water conservation in Zhengzhou were the large change of cultivated land area and the large amount of water conservation per unit area of forest and grass land. Forest and grassland land has the highest water conservation capacity, accounting for about 20% of the land area in Zhengzhou, providing 40% of the water conservation capacity. [Conclusion] The research results will provide scientific basis for future land use planning and water conservation and protection of ecosystem in Zhengzhou.