Hydrogeochemical Characteristics of Karstic Springs in Western Turkey
Abstract
A hydrogeochemical approach using recharge, circulate, and discharge data from different carbonate rocks with varying ages were collected and analyzed from several springs in Western Turkey to better understand Karstic aquifers. Samples were collected from the Paleozoic-Mesozoic marbles (K1, K3, K9, Sakarbasi and Kaymaz), the Jura-Cretaceous limestones (Sagalasus, Nardin, Deliktas, Kayaağzi, and Adaköy Springs), and the Neocene limestones (K7 and K8). In situ measurements in wet and dry seasons were compared in order to explain aquifer characteristics and how they would be affected by varying types of precipitation resulting from changes in climate. The groundwaters have pH values ranging from 6 to 8.9, temperatures (T) vary from 6 to 35°C, and electrical conductivity (EC) values go from 140 to 985 μS/cm. EC results show that variations depended on not only circulation depth but also on lithology. The EC-Temperature and DO (Dissolved oxygen) relationships indicate the existence of waters with different origins. The groups that have high EC, high T, and low DO values represent the deep circulating water (K7, K1, and Hitit Pinari). Low EC, low T and high DO values represent the shallow circulating waters (K3, K8, K9, Pinargözü, Sagalasus, Yesilköy, Narli, and Adaköy Springs). Low variations of the measurements in both the wet and dry seasons (all nearly at constant temperature with low chemical composition variations) reveal that fracture permeability is dominated by diffused-flow-controlled groundwater flow (K1, K7, K3, K8 and K9). High variations of the measurements (temperature and chemical composition) in both the wet and dry seasons show focused infiltration from karstic structures (sinkholes, fractures, and joints) and dominated by conduit permeability. Climate change data shows that the number of heavy precipitation days has been increasing, especially in western Turkey, and usually cause extreme flood events. Despite a year in which cumulative precipitation may increase, the total amount of recharge may be less in aquifers dominated by diffused flow. This research reinforces the hypothesis that aquifers controlled by conduit permeability have rapid recharge and discharge rates after flood events, developed karst sinkholes allow fast percolation into the aquifer, up to 80 % of heavy rainfalls, and rapid recharge causes rapid discharge rates from springs, which have been observed after storms. So it can be said that the recharge of aquifers (shallow and dominated by conduit permeability) can increase, but at the same time this situation can cause extreme flood events.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMED13A0760D
- Keywords:
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- 1832 HYDROLOGY Groundwater transport;
- 1831 HYDROLOGY Groundwater quality;
- 1858 HYDROLOGY Rocks: chemical properties;
- 1833 HYDROLOGY Hydroclimatology