An Integrated Modeling System for the Evaluation of Water Resources in Coastal Agricultural Watersheds: Application in Almyros Basin, Thessaly, Greece

Abstract

This study presents an integrated modeling system for the evaluation of the quantity and quality of water resources of coastal agricultural watersheds. The modeling system consists of coupled and interrelated models, including (i) a surface hydrology model (UTHBAL), (ii) a groundwater hydrology model (MODFLOW), (iii) a crop growth/nitrate leaching model (REPIC, an R-ArcGIS-based EPIC model), (iv) a groundwater contaminant transport model (MT3DMS), and (v) a groundwater seawater intrusion model (SEAWAT). The efficacy of the modeling system to simulate the quantity and quality of water resources has been applied to the Almyros basin in Thessaly, Greece. It is a coastal agricultural basin with irrigated and intensified agriculture facing serious groundwater problems, such as groundwater depletion, nitrate pollution, and seawater intrusion. Irrigation demands were estimated for the main crops cultivated in the area, based on precipitation and temperature from regional weather stations. The models have been calibrated and validated against time-series of observed crop yields, groundwater table observations, and observed concentrations of nitrates and chlorides. The results indicate that the modeling system simulates the water resources quantity and quality with increased accuracy. The proposed modeling system could be used as a tool for the simulation of water resources management and climate change scenarios.

Corrigendum: Water Supply 21 (6), 2748–2759: Impacts of irrigation and nitrate fertilization scenarios on groundwater resources quantity and quality of Almyros Basin, Greece

“…The chloride fluxes have been simulated using the SEAWAT model for the period of 1991 to 2018 and the simulation was performed for all the four (4) scenarios (S1, S1, S3, S4) and evaluated as described in the study of (Lyra et al 2021a). The maximum chlorides concentration reduction in all scenarios reach a value of 18,000 mg/L in the north coastline area that is salinized in the baseline scenario S0 (Lyra et al 2021b). The scenarios S1 and S3 show a spatial average reduction of 47 mg/L, and the scenarios S2 and S4 a spatial average of 57 mg/L, the latter has a larger extent of positive impact on the aquifer's water quality (Figure 5(d)).…”

“…The nitrate concentrations of scenario S4 are spatially lower than the results for the scenario S3. Although in the scenario S4, a large extent of the aquifer is covered by rainfed cultivations and the nitrate fertilization is reduced, the results show less reduction of the nitrate concentrations in spotted central areas, possibly due to the higher leaching rates of cultivars and the clayish material of the aquifer in that area (see Figure 3-Geological view in Lyra et al (2021b)).…”

“…The practices of deficit irrigation (S1,S3) and deficit irrigation and rainfed conditions (S2,S4) show positive water balance at the end of the rainy period, and reduced deficit balance during the irrigation period. The annual water deficit of the baseline scenario S0 is 12.02 hm 3 (Lyra et al 2021b) is minimized in the deficit irrigation case to 7.9 hm 3 (scenarios S1 and S3), and in the deficit irrigation and rainfed cultivation case (scenarios S2 and S4) to 0.3 hm 3 . The annual water deficit alleviation follows the water economy achieved with the irrigation practices.…”

A Comprehensive Evaluation Model of Ammonia Pollution Trends in a Groundwater Source Area along a River in Residential Areas

“…Obviously, groundwater resources are one of the main sources of water for industrial and agricultural purposes and in daily life [11][12][13]. Especially in some arid and semi-arid areas, groundwater resources are the only source of water supply [14][15][16][17]. For example, in China, domestic water consumption of 33% of the cities in arid areas are totally dependent on groundwater resources.…”

“…For example, in China, domestic water consumption of 33% of the cities in arid areas are totally dependent on groundwater resources. Therefore, a large number of researchers have studied the areas, groundwater resources are the only source of water supply [14][15][16][17]. For example, in China, domestic water consumption of 33% of the cities in arid areas are totally dependent on groundwater resources.…”