Identifying potential effects of climate change on the development of water resources in Pinios River Basin, Central Greece

The aim of the present study is to assess the future spatial and temporal distribution of precipitation and temperature, and relate the corresponding change to water resources’ quantitative status in Pinios River Basin (PRB), Thessaly, Greece. For this purpose, data from four Regional Climate Models (RCMs) for the periods 2021–2100 driven by several General Circulation Models (GCMs) were collected and bias-correction was performed based on linear scaling method. The bias-correction was made based on monthly precipitation and temperature data collected for the period 1981–2000 from 57 meteorological stations in total. The results indicate a general trend according to which precipitation is decreasing whilst temperature is increasing to an extent that varies depending on each particular RCM–GCM output. On the average, annual precipitation change for the period 2021–2100 was about − 80 mm, ranging between − 149 and + 35 mm, while the corresponding change for temperature was 2.81 °C, ranging between 1.48 and 3.72 °C. The investigation of potential impacts to the water resources demonstrates that water availability is expected to be significantly decreased in the already water-stressed PRB. The water stresses identified are related to the potential decreasing trend in groundwater recharge and the increasing trend in irrigation demand, which constitutes the major water consumer in PRB

ESTABLISHING A HYDROLOGIC OBSERVATORY TO SUPPORT THE DETERMINATION OF THE LONG-TERM AVAILABLE (GROUND-) WATER RESOURCES IN THESSALY BASIN (CENTRAL GREECE)

In order to maintain agriculture as a key economic sector in Thessaly basin it is mandatory to adapt the regional (ground-)water management to the renewable (ground-)water resources. The obstacles impeding the implementation of regionally adapted and efficient (ground-)water management strategies are manifold. Due to lack of reliable time series from meteorological and runoff monitoring networks the available renewable groundwater resources cannot be quantified with high accuracy. The lack of vegetation specific parameters additionally impedes the model-based determination of actual evapotranspiration rates. Thus, even the possibilities to determine the total available renewable water resources (total runoff) is limited. Against the background that in situ groundwater recharge generation contributes only to a small extent to the available groundwater resources in Thessaly basin, it is also part of the overall research strategy of a Greek – German cooperation project to determine the lateral groundwater inflow from adjacent mountainous aquifers into the Thessaly basin. For this purpose state-of-the-art devices to quantify hydrologic fluxes in detail have been installed in a test site located in the transition zone of the basin and adjacent mountains (Agia observatory): (a) 2 fully equipped precipitation and climate stations, (b) A wireless sensor network for measuring spatial soil water content variability as a data basis for determining vegetation specific evapotranspiration parameters, and (c) A groundwater observation network and pumping wells for determining hydraulic parameters and seasonal patterns of groundwater velocity in the transition zone. The derived parameters and lateral groundwater flow rates will then additionally be used to support the implementation and adaptation of the water balance model mGROWA (Herrmann et al. 2015) in the entire Thessaly basin, especially with regard to the model-based assessment of the sustainably available groundwater resources

Assessment of climate change impact in the hydrological regime of River Pinios Basin, central Greece

In order to assess the potential impacts of climate change in the hydrologic regime of River Pinios Basin, an area-differentiated model for total run-off (Qt) estimation based on the GROWA model was applied with bias-corrected precipitation and temperature data from four regional climate models (RCMs) for the projected periods 2020–2050 (period A) and 2050–2080 (period B). Bias correction was performed using the linear scaling approach. As a reference basis, monthly precipitation data from 57 meteorological stations and average temperature data from 17 stations were analyzed for the period 1980–2000. Relative assessments were achieved by comparing reference to projected periods values for Qt, after incorporating bias-corrected projected climate data from the four RCMs driven by several general circulation models (GCMs) as input data to the hydrological model. Results showed that all RCM–GCM combinations lead to a considerable decrease in total run-off with variable rates between the examined projected periods; the greatest reduction of Qt (62%) from the reference period was forecasted for period A (2020–2050), and was simulated when GROWA model ran with input data from HIRHAM5 model driven by ARPEGE GCM, which indicated greater decrements in precipitation and increments in temperature. Regarding the estimations of total run-off for the end of the projected periods (2080) with simulated climatic data input from HIRHAM–ARPEGE, RACMO–ECHAM5 and REMO–ECHAM5 RCM–GCM combinations, a significant adverse impact to the overall water budget is forecasted, as the total amount of Qt is decreased from 46 to 66%. On the contrary, when Qt was simulated with climatic data from RCA4 RCM driven by HadCM3, smoother rates were exhibited due to smaller variations of precipitation and temperature from the reference period and the relevant Qt reduction by the end of the projection (2080) is 22%

Integrated modeling as a decision-aiding tool for groundwater management in a Mediterranean agricultural watershed

Δημοσίευση σε επιστημονικό περιοδικόSummarization: A decision-aiding methodology for agricultural groundwater management is presented; it is based on the combination of a watershed model, a groundwater flow model, and an optimization model. This methodology was applied to an agricultural watershed in northeastern Greece. The watershed model used was the Soil and Water Assessment Tool (SWAT), which provided recharge rates for the aquifers. These recharge rates were imported in the well-known MODFLOW groundwater flow model. Both models were calibrated and verified using field data. Then, the nonlinear optimization problem was solved by a piecewise linearization process, in which the Simplex algorithm was applied sequentially. Apart from several pumping and climate change sensitivity scenarios, a land use change scenario and a climate change scenario, combining the three models, were tested, showing the ability of this methodology to be used in the decision-making process.Presented on: Hydrological Processe

Operational precise irrigation for cotton cultivation through the coupling of meteorological and crop growth models.

In this paper, we tested the operational capacity of an interoperable model coupling system for the irrigation scheduling (IMCIS) at an experimental cotton (Gossypium hirsutum L.) field in Northern Greece. IMCIS comprises a meteorological model (TAPM), downscaled at field level, and a water-driven cultivation tool (AquaCrop), to optimize irrigation and enhance crop growth and yield. Both models were evaluated through on-site observations of meteorological variables, soil moisture levels and canopy cover progress. Based on irrigation management (deficit, precise and farmer’s practice) and method (drip and sprinkler), the field was divided into six sub-plots. Prognostic meteorological model results exhibited satisfactory agreement in most parameters affecting ETo, simulating adequately the soil water balance. Precipitation events were fairly predicted, although rainfall depths needed further adjustment. Soil water content levels computed by the crop growth model followed the trend of soil humidity measurements, while the canopy cover patterns and the seed cotton yield were well predicted, especially at the drip irrigated plots. Overall, the system exhibited robustness and good predicting ability for crop water needs, based on local evapotranspiration forecasts and crop phenological stages. The comparison of yield and irrigation levels at all sub-plots revealed that drip irrigation under IMCIS guidance could achieve the same yield levels as traditional farmer’s practice, utilizing approximately 32% less water, thus raising water productivity up to 0.96 kg/m3.N/