Action A.2: Geo-environmental, hydrogeological and geochemical study of the areas of temporary ponds (3170*)

Mediterranean temporary ponds are, by definition, wetlands that present a seasonal hydrologic period. Ecosystem functions and, consequently, the biota of the ponds depend strongly on the hydrological status. The characteristic flora and fauna species are highly specialised and vulnerable to any changes in hydrology. The establishment of a quantitative assessment of the hydrological functions and the identification of potential direct or indirect modifications require frequent monitoring of the components of the water cycle, and of their effects on the seasonal and interannual variations of the pond water level. In addition, the biological phenomena of the ponds strongly depend on the hydric state and geochemistry of the sediments, the water chemistry, and their interactions. These are also controlled by flooding/drying cycles through soil redox potential changes.

Action A2 consists in a comprehensive study of the geological and hydrogeological characteristics of the temporary ponds on Mt. Oiti (at Leivadies, Greveno, Louka, and north of Trapeza) and on Mt. Kallidromo (at Nevropoli, east of Nevropoli, and at Souvala) in order to describe the surface micro-geomorphology, the underground geological setting, the hydrological conditions and the geochemistry of the ponds. The components of the water cycle of the ponds (geology and geomorphology of the catchment area, rainfall and evapo-transpiration, relationship with underground water) will be investigated. The water cycle interaction with the landscape and the geological basement will be described, the areas of erosion and deposition within the catchment area will be defined, and the interannual changes will be quantified.

A complete base study (points 1 to 6 below) will be made during the first year of the project. This will be followed up in the second year by monitoring of the hydrological cycle (points b to d below) and, should the local situation prove that they are of priority, of water and sediment quality (points 5 and 6 below). The study will include:

1. The geological and geomorphological characteristics of the catchment area of the ponds, including mineralogy and geochemistry of the bedrock, the bottom sediments and the efflorescence deposits [evaporites], mainly formed at the lake margins during dry periods. Existing data, e.g. geological and pedological maps will be collected and supplemented by field observations and measurements supported by remote sensing data interpretation.
2. Geophysical surveys with electrical resistivity tomography. Through this procedure the geological and hydrogeological conditions will be identified and defined (geophysical stratigraphy, subsurface relief, identification of the hydrogeological regime, etc.).
3. Bathymetry of the pools and topography of the surrounding areas using state of the art topographic equipment (DGPS and Real Time Kinematics) and measurement of surface water levels.
4. Climatology data, including collection of both historical and current data from the closest existing observation networks and current data throughout the duration of the project collected from in situ meteorological stations. Two automatic meteorological stations will be established on three-meter-high towers, one at each mountain at the most appropriate location regarding the reliability of the measurements. The stations will consist of rain gauge, thermometer, hygrometer, wind anemometer, sunshine recorder and barometer, powered by solar panels and capturing continuous measurements in a data logger.
5. Water quality assessment including sampling for: i) nutrients (total phosphorus, total dissolved phosphorus, phosphate, total nitrogen, total dissolved nitrogen, nitrate, nitrite and ammonium) analysed by colorimetric methods; ii) chemical characterisation by measuring major element ions using Atomic Absorbance Spectroscopy [AAS], [i.e. magnesium, calcium, sodium, bicarbonate, sulphate], but also trace elements content using Graphite Furnace Atomic Absorption Spectroscopy [GFAAS] and Inductive Coupled Plasma Mass Spectroscopy [ICP-MS] [i.e. arsenic, chromium, boron, nickel, strontium, lead, zinc, copper, iron]; iii) in situ measurements of the physical parameters including pH, Eh, electrical conductivity, temperature, Total Dissolved Salts [TDS], Diluted Oxygen with special equipment; iv) measurements of biogeochemical parameters including Chemical Oxygen Demand [COD], Biogeochemical Oxygen Demand [BOD], Total Organic Carbon [TOC] in dry and wet periods. The frequency of the sampling depends on the flooding periods.
6. Soil sediment assessment including: i) recording of settling and re-suspension rates, iron, silica, aluminum, phosphorus, sodium, potassium content in surface sediment and suspended soil, using X-Ray Florescence Spectroscopy [XRF]; ii) soluble and insoluble mineral content of the soil [evaporitic salts such as gypsum, thenardite, trona, epsomite, hydromagnesite] using X-Ray Defraction Spectroscopy [XRD], Scanning Electron Microscopy [SEM] and microprobe analysis; iii) organic matter content and different sedimentary fractions with certified equipment.