Artesian systems (Artezyen Sistemleri) The term artesian system (artezyen sistem) can be applied to any system in which groundwater is confined and builds up high hydrostatic pressure. Water in such a system is able to rise above the level of the aquifer if a well is drilled through the confining layer, thereby reducing the pressure and forcing the water upward. For an artesian system to develop: 1. The aquifer must be confined above and below by aquicludes to prevent water from escaping 2. The rock sequence is usually tilted and exposed at the surface, enabling the aquifer to be recharged 3. There is sufficient precipitation in the recharge area to keep the aquifer filled. (Area of recharge for aquifer) (Artesian pressure surface) Dirik ve ener, 2007 (Shale aquicludes)

(Sandstone aquifers) Effects of Groundwater Action Caves (Maaralar) are naturally formed underground chambers. Most caves develop when slightly acidic groundwater dissolves limestone along joints and bedding planes, opening up cavern systems as the rock components are carried away in solution. Natural groundwater is often slightly acidic because of the solution of carbondioxide from atmosphere or from soil gases. Ca++ +2HCO3 Development of caves (solution) H2O+ CO2+CaCO3 Development of flowstone and dripstone (precipitation) Deposits of calcite built up in caves by dripping water are called dripstone (damlata). Stalactites (sarkt) are icicle-like structures hanging from cave ceilings. Stalagmites (dikit) are coneshaped masses of dripstone formed on cave floors, generally directly below stalactites. As a stalactite grows downward and a stalagmite grows upward, they may eventually join to form a column (kolon).

Plummer vd, 2007 Sinkholes (dolinler) are closed depressions found on land surfaces underlain by limestone. They form either by collapse of a cave roof or by solution as descending water enlarges a crack in limestone. An area with many sinkholes and cave systems beneath the land surface is said to have karst topography (karst topografyas). Karst topography is characterized by caves, springs, sinkholes, solution valleys (znme vadileri) and disappearing streams (gzden kaybolan akarsular) . (Deeply intrenched permanent stream) (Cave) /uvalalar (Solution valleys) (Springs) /Dolin (Sinkhole) /Ddenler (Disappearing streams) Sinkholes and Solution valleys Cave Formation Monroe and Wicander, 2001 Monroe and Wicander, 2001 Dirik ve ener, 2007

Modification of the Groundwater System and Their Effects Groundwater is a valuable natural resource that is rapidly being exploited with little regard to the effects of overuse and misuse. Modifications of the groundwater system may have many consequences, including 1. Lowering of the water table , causing wells to dry up (Withdrawing groundwater at a significantly greater rate than it is replaced by either natural or artificial recharge can have serious effects.) 2. Salt water intrusion (tuzlu su giriimi) 3. Subsidence (kme) 4. Contamination (kirlilik) Salt water intrusion Water table) (Fresh groudwater) (Cone of depression) (Cone of ascension) Dirik ve ener, 2007 (Pumping well) (ocean) (Salty groundwater) (Recharge well)