Study on Hydrologic Effects of Land Use Change Using a Distributed Hydrologic Model in the Dynamic Land Use Mode

Qingyan Sun,Xin He,Qinghua Luan,Chu Wu,Lingjia Yan,Zepeng Li,Hui Guo,Tao Qin,Chuiyu Lu,Bo Zhang

doi:10.3390/w13040447

Abstract

It is reasonable to simulate the hydrologic cycle in regions with drastic land use change using a distributed hydrologic model in the dynamic land use mode (dynamic mode). A new dynamic mode is introduced into an object-oriented modularized model for basin-scale water cycle simulation (MODCYCLE), a distributed hydrologic model based on sub-watersheds, and the hydrological response unit (HRU). The new mode can linearly interpolate data for the years without land use data and consistently transfer HRU water storage between two adjacent years after a land use data update. The hydrologic cycle simulation of the Sanjiang Plain in China was carried out from 2000 to 2014 in the dynamic mode using land use maps of 2000, 2005, 2010, and 2014. Through calibration and validation, the performance of the model reached a satisfactory level. Replacing the land use data of the calibrated model using that of the year 2000, a comparison model in the static land use mode (static mode) was built (i.e., land use unchanged since 2000). The hydrologic effects of land use change were analyzed using the two models. If the land use pattern remained unchanged from 2000, despite the average annual runoff increasing by 4% and the average annual evapotranspiration decreasing by 4% in this region only, the groundwater storage of the plain areas in 2014 would increase by 4.6 bil. m3 compared to that in 2000, rather than the actual decrease of 4.7 bil. m3. The results show that the fluxes associated with groundwater are obviously more disturbed by land use change in the Sanjiang Plain. This study suggests that the dynamic mode should be used to simulate the hydrologic cycle in regions with drastic land use change, and the consistent transfer of HRU water storage may be considered in the dynamic mode.

Highlights

Human activities have caused a large number of natural landscapes to be replaced by artificial landscapes, resulting in changes in land use/land cover patterns [1,2]
The new mechanism of the dynamic land use update has been realized in the objectoriented modularized model for basin-scale water cycle simulation (MODCYCLE), a hydrologic model based on sub-watersheds and hydrological response unit (HRU) [46] and closely coupled with the groundwater numerical model [47]
The objectives of this paper were to (1) establish the hydrologic model of the Sanjiang Plain in the dynamic land use mode and test its performance, (2) establish the hydrologic model of the study area in the static land use mode and compare the hydrologic differences between the two models to clarify the effects of land use change, and (3) compare the differences between the direct and consistent transfer of HRU water storage in the dynamic land use mode to illustrate the necessity of the consistent transfer

Summary

Introduction

Human activities have caused a large number of natural landscapes (woodland, grassland, wetland, etc.) to be replaced by artificial landscapes (farmland, cities, roads, etc.), resulting in changes in land use/land cover (land use for short) patterns [1,2]. There have been many studies on the impacts of land use/land cover change (land use change for short) on various aspects of the hydrologic cycle. These include analyses of the effects of urbanization; opening up of wasteland for farming; and changes to agricultural land in terms of runoff, evaporation, groundwater recharge, and basic flow under various regional conditions (e.g., global scale, arid, agricultural, urban areas, and watersheds) [3,4,5,6,7,8,9,10,11]. There may be two reasons for these contradictions: one is the lack of land use data, and the other is that the model can only take one land use map as input [17]

Objectives

Methods

Results

Discussion

Conclusion