Effects of Urban Activities on Coastal Aquifers: Case Study in the Eastern Black Sea Basin




The Eastern Black Sea Basin is the highest rainfall area in Turkey with an average rainfall of 1300 mm. However, this region is one of the poorest regions in terms of spring and groundwater potential due to its topography having extremely high slopes, and impermeable-less permeable rocks exposed in the basin. Alluvium, which is carried by streams flowing from north to south along the Eastern Black Sea coastline, are important in terms of groundwater. Alluvium, of which thickness and width decrease from north to south, has a length of 1-16 km and a width of 50-1500 m. Water is provided from wells that are drilled in alluvium with a thickness of up to 40 m. According to DSI (2015) data, the static water level is between 0.3 and 1 m, while the dynamic water level is between 5 and 15 m. The volume of water stored in the coastal aquifers of the Eastern Black Sea Basin is 238 hm(3). Some of these aquifers are still used and some were used in the past as drinking water sources. However, in recent years, construction such as industrial sites, quarries, coal storage and packaging facilities, warehouses and buildings of some public institutions and organizations has been increasing on these aquifers, which form partially flat areas between narrow valleys. This construction adversely affects both the quantity and quality of shallow groundwater stored in alluvium. The aquifers are the most important groundwater sources in the basin and are used to supply drinking and potable water for 4 cities. Degirmendere and Taslidere aquifers, which provided drinking-potable water in the past, were completely under stress by urbanization and the use of groundwater was terminated. The urban activities on Melet, Civil, Pazarsuyu (Ordu) and Batlama and Kesap (Giresun) aquifers, which are located in the settlement area, continue to increase. The aquifers of Curi, Yaglidere, Gelevera, Akhisar, Yanbolu, Baltaci, Iyidere and Firtina are less affected by urban activities. Among them, Curi, Yaglidere, Iyidere and Firtina aquifers are aquifers with high groundwater capacities. In order to be able to use the Eastern Black Sea coastal aquifers for many years, it is necessary to protect them in terms of quality and recharging.