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The objective of this study was to identify seasonal and spatial trends and soil salinization patterns in a part of Rhodope District irrigated land, northeastern Greece, located east of Vistonis Lagoon. The study area is irrigated from a coastal aquifer, where salt water intrusion occurs because of extensive groundwater withdrawals. Fourteen monitoring sites were established in harvest fields in the study area, where soil samples were collected. Electrical conductivity (ECe), pH, and ion concentrations were determined in the saturated paste extract of the soil samples in the laboratory using standard methods. A clear tendency was observed for ECe to increase from April to September, i.e., within the irrigation period, indicating the effect of saline groundwater to soil. In the last years, the change from moderately sensitive (e.g., corn) to moderately tolerant crops (e.g., cotton) in the south part of the study area indicates the impacts of soil salinity. The study proposes management methods to alleviate this problem.

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This paper presents the development of a regional flow simulation model of the streamYaquifer system of Ismarida plain, northeastern Greece. It quantifies the water budget for this aquifer system and describes the components of groundwater and the characteristics of this system on the basis of results of a 3-year field study. The semiconfined aquifer system of Ismarida Lake plain consists of unconsolidated deltaic clastic sediments, is hydraulically connected with Vosvozis River, and covers an area of 46.75 km 2 . The annual precipitation ranges in the study area from 270 to 876 mm. Eighty-seven irrigation wells are densely located and have been widely used for agricultural development. Groundwater flow in this aquifer was simulated with MODFLOW. Model calibration was done with observed water levels, and match was excellent. To evaluate the impacts of the current pumping schedule and propose solutions, four management scenarios were formulated and tested with the model. Based on model results, the simulated groundwater budget indicates that there must be approximately 33% decrease of withdrawals to stop the dramatic decline of groundwater levels. The application of these scenarios shows that aquifer discharge to the nearby river would be very low after a 20-year period.