Evaluation and hydrological impact of land-use changes in the Longtan basin

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Ó Indian Academy of Sciences (0123456789().,-volV)(0123456789( ).,-volV)

Evaluation and hydrological impact of land-use changes in the Longtan basin GUIYAN MO1, YONGXIANG ZHANG2,* , YA HUANG3, CHONGXUN MO3 and QING YANG3 1 College 2

of Computer and Information, Hohai University, Nanjing 211 100, China. School of Management Science and Engineering, Guangxi University of Finance and Economics, Nanning 530 003, China. 3 College of Civil and Architectural Engineering, Guangxi University, Nanning 530 004, China. *Corresponding author. e-mail: [email protected] MS received 11 February 2020; revised 23 May 2020; accepted 11 June 2020

Compared to climate change, land-use changes were the main driving factors to short-term hydrological variety. To evaluate land-use types variation and quantify its hydrological impact, this paper identiBed the temporal-spatial features and simulated the hydrological process of different land-use types over the last two decades (1990–2010) based on the soil and water assessment tool (SWAT). Meanwhile, the possible inCuence of land-use changes on streamCow in the next 30 years (2020–2050) was also considered. Results indicated that (1) land-use types mainly constituted of forest land, grassland and cultivated land, which had the largest decreasing rate of 17.34 km2/10a. At the same time, inter-conversion mainly conducted among the main land-use types and had a similar transfer structure for these two sub-periods (1990–2000, 2000–2010) during 1990–2010, with a more dramatic transformation in 2000–2010. (2) Simulated annual and monthly surface runoA did not vary greatly from 1990 to 2010 and presented a relatively uniform monthly distribution. At the same time, the increased vegetation coverage (forest land and grassland) can not only reduce surface runoA but also prevent peak Cood with increasing and decreasing steeply. (3) Finally, hydrological variability to the future land-use change will not be intensive, which possibly related to the undeveloped regional economic and insignificant human activities. But it also needed some measures to maintain a balanced nature, such as the soil and water conservation measures and returning cultivated land to forest land and grassland. Keywords. Land-use changes; evaluation; hydrological responses; SWAT model; Longtan basin.

1. Introduction Vegetation coverage changes as farming, tree/grass planting, construction, etc., aAect the regional water balance/hydrologic cycle as well as the spatial distribution of surface latent heat (Gong et al.

2014; Wang et al. 2015). Meanwhile, land-use changes interfere the catchment’s hydrological and rainfall-runoA process by disordering the equilibrium relationship between water and energy. Furthermore, land-use variability inCuences the temporal-spatial distribution of water resources

Supplementary materials pertaining to this article are available on the Journal of Earth Science Website (http://www.ias.ac.in/ Journals/Journal˙of˙Earth˙System˙Science).

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