GroMoPo Metadata for South Platte SWAT-MODFLOW model

Climate change can have an adverse effect on agricultural productivity and water availability in semi-arid regions, as changes in surface water availability lead to groundwater depletion and resultant losses in crop yield. These inter-relationships necessitate an integrated management approach for surface water, groundwater, and crop yield as a holistic system. This study quantifies the future availability of surface water and groundwater and associated crop production in a large semi-arid agro-urban river basin in which agricultural irrigation is a leader consumer of water. The region of study is the South Platte River Basin (72,000 km(2)), Colorado, USA. The coupled SWAT-MODFLOW modeling code is used as the hydrologic simulator and forced with five different CMIP5 climate models downscaled by Multivariate Adaptive Constructed Analogs (MACA), each for two climate scenarios, RCP4.5, and RCP8.5, for 1980-2100. The hydrologic model accounts for surface runoff, soil lateral flow, groundwater flow, ground-water-surface water interactions, irrigation from surface water and groundwater, and crop yield on a per-field basis. In all climate models and emission scenarios, an increase of 3 to 5 degrees C in annual average temperature is projected. Whereas, variation in the projected precipitation depends on topography and distances from mountains. Based on the results of this study, the worst-case climate model in the basin is IPSL-CM5A-MR-8.5. Under this climate scenario, for a 1 degrees C increase in temperature and the 1.3% reduction in annual precipitation, the basin will experience an 8.5% decrease in stream discharge, 2-5% decline in groundwater storage, and 11% reduction in crop yield. These results indicate the significant effect of climate change on water and food resources of a large river basin, pointing to the need for immediate implementation of conservation practices. (C) 2021 Elsevier B.V. All rights reserved.

气候变化对半干旱地区的农业生产力与水资源可利用量可产生显著不利影响：地表水可利用量的变化会引发地下水枯竭，进而导致作物减产。上述相互关联的水文与农业过程，要求将地表水、地下水与作物产量作为一个整体系统开展综合管理。
本研究针对一个以农业灌溉为第一用水大户的大型半干旱农业-城市复合型流域，量化了未来地表水与地下水的可利用量及相关作物生产情况。研究区域为美国科罗拉多州南普拉特河流域（面积72000平方千米）。
本研究采用耦合SWAT-MODFLOW模型代码作为水文模拟器，使用经多变量自适应构造类比法（Multivariate Adaptive Constructed Analogs，MACA）降尺度的5套不同第五次耦合模式比较计划（Coupled Model Intercomparison Project Phase 5，CMIP5）气候模式驱动数据，分别针对RCP4.5与RCP8.5两种典型浓度路径，模拟了1980年至2100年的水文过程。
该水文模型可逐地块模拟地表径流、土壤侧向流、地下水流动、地表水-地下水交互过程、地表水与地下水灌溉取水，以及作物产量。
所有气候模式与排放情景下，均预测年平均气温将升高3至5摄氏度。而降水的预测变化则取决于地形与距山脉的距离。
基于本研究结果，该流域表现最差的气候模式为IPSL-CM5A-MR-8.5。在该气候情景下，当气温升高1摄氏度且年降水量减少1.3%时，流域内河流径流量将下降8.5%，地下水储量减少2%至5%，作物产量降低11%。
上述结果表明，气候变化对大型流域的水与粮食资源具有显著影响，亟需立即实施水资源保护措施。©2021 Elsevier B.V. 保留所有权利。