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| Titel |
Integrated assessment of the impact of climate and land use changes on groundwater quantity and quality in the Mancha Oriental system (Spain) |
| VerfasserIn |
M. Pulido-Velazquez, S. Peña-Haro, A. Garcia-Prats, A. F. Mocholi-Almudever, L. Henriquez-Dole, H. Macian-Sorribes, A. Lopez-Nicolas |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 19, no. 4 ; Nr. 19, no. 4 (2015-04-10), S.1677-1693 |
| Datensatznummer |
250120677
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| Publikation (Nr.) |
 copernicus.org/hess-19-1677-2015.pdf |
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| Zusammenfassung |
| Climate and land use change (global change) impacts on groundwater systems
cannot be studied in isolation. Land use and land cover (LULC) changes have a
great impact on the water cycle and contaminant production and transport.
Groundwater flow and storage are changing in response not only to climatic
changes but also to human impacts on land uses and demands, which will alter
the hydrologic cycle and subsequently impact the quantity and quality of
regional water systems. Predicting groundwater recharge and discharge
conditions under future climate and land use changes is essential for
integrated water management and adaptation. In the Mancha Oriental system
(MOS), one of the largest groundwater bodies in Spain, the transformation
from dry to irrigated lands during the last decades has led to a significant
drop of the groundwater table, with the consequent effect on stream–aquifer
interaction in the connected Jucar River. Understanding the spatial and
temporal distribution of water quantity and water quality is essential for a
proper management of the system. On the one hand, streamflow depletion is
compromising the dependent ecosystems and the supply to the downstream
demands, provoking a complex management issue. On the other hand, the intense
use of fertilizer in agriculture is leading to locally high groundwater
nitrate concentrations. In this paper we analyze the potential impacts of
climate and land use change in the system by using an integrated modeling
framework that consists in sequentially coupling a watershed agriculturally
based hydrological model (Soil and Water Assessment Tool, SWAT) with a groundwater flow model developed in MODFLOW, and with a nitrate mass-transport model in MT3DMS. SWAT model outputs (mainly
groundwater recharge and pumping, considering new irrigation needs under
changing evapotranspiration (ET) and precipitation) are used as MODFLOW
inputs to simulate changes in groundwater flow and storage and impacts on
stream–aquifer interaction. SWAT and MODFLOW outputs (nitrate loads from
SWAT, groundwater velocity field from MODFLOW) are used as MT3DMS inputs for
assessing the fate and transport of nitrate leached from the topsoil. Three
climate change scenarios have been considered, corresponding to three
different general circulation models (GCMs) for emission scenario A1B that
covers the control period, and short-, medium- and long-term future periods.
A multi-temporal analysis of LULC change was carried out, helped by the study
of historical trends (from remote-sensing images) and key driving forces to
explain LULC transitions. Markov chains and European scenarios and
projections were used to quantify trends in the future. The cellular automata
technique was applied for stochastic modeling future LULC maps. Simulated
values of river discharge, crop yields, groundwater levels and nitrate
concentrations fit well to the observed ones. The results show the response
of groundwater quantity and quality (nitrate pollution) to climate and land
use changes, with decreasing groundwater recharge and an increase in nitrate
concentrations. The sequential modeling chain has been proven to be a
valuable assessment tool for supporting the development of sustainable
management strategies. |
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