Kovada Gölü (Isparta-Eğridir) ve dolayının karst hidrojeolojisi

Abstract

Havada Gölü ve Dolayının Karst Hidra jeolojisi" konulu bu tez kapsamında yörenin jeolojisi ve karst hid rojeolojisi incelenmiş ve insan eliyle bozulmuş doğal ya pısı nedeniyle kurumakta olan Kovada Golü'nün kurumadan, uzun yıllar varlığını sürdürebilmesi araştırılmıştır. Öncelikle inceleme alanının 1/25000 ölçekli jeoloji hari tası hazırlanarak genel ve yapısal özellikler belirlenmiş tir. Çalışma alanının sınırları belirlenirken karstik kireçtaşlarının devamlılıkları izlenmiş ve harita geçirim siz sınırları içerecek şekilde sanlandırılmıştır. Jeolo ji çalışması sürdürülürken, birimlerin hidro jeolojik özel likleri de incelenerek 1/25000 ölçekli hidrojeoloji hari tası hazırlanmıştır. Geniş bir alanı kapsayan jeoloji ve hidrojeoloji çalışmalarından sonra çalışmanın odak nokta sını oluşturan Kovada Gölü ve dolayındaki çalışmalara ağırlık verilmiştir. Kovada Gölü ve yakın çevresindeki düdenler, süreksizlikler, kaçaklar ve beslenim noktaları belirlenmiş, bunların değişik su seviyelerindeki davranış ları gözlenmiş, kaçak noktaları ile gölün ilişkisi ince lenmiştir. Kovada Gölü ile ilişkisi saptanan kaynakların debileri ile göl hacmi arasında çok sayıda korelasyon ya pılmış ve gölden kaynak noktalarına kaçan suyun miktarı saptanmıştır. Bu çalışmaların ardından Kovada Golü'nün su bilançoları değişik yıllar için hazırlanmıştır. Bilan çolar yardımıyla gölün yağış ve yüzeysel akıştan başka yeraltısuyu beslenimi de olduğu ve her yıl için gölde su giderinin gelirinden fazla olduğu saptanmıştır. Sonuçta, jeolojik ve hidra jeolojik ortamı ayrıntılı olarak tanım lanan Kovada Golü'nün bu ortam içerisindeki varlığını uzun yıllar koruyabilmesinin ancak bilançolarda görülen su açı ğı kadar ilave su verilmesiyle mümkün alabileceği saptan mıştır.

Until 1976, the Kovada Lake uıas only temporary recipient to mater; it served as a regulatory storage. The Eğir dir Lake water entered the lake by one channel and was discharged by another channel leading to the hydropower plants. So a surplus of water from the Eğirdir Lake was discharged to Kovada Lake in order to keep the lake levels steady. However in 1976, instead of entrance and exit channel, a by-pass was excavated so that the Eğirdir Lake water flows directly to the hydropower plants. That is why in recent years the lake dried during the summer seasons since 1976. In this study. 50 sinkholes which cause water leakages around the coast of the lake were found. These water leakages origination from the sinkholes can be seen in the Gökpınar Spring located at 5 kms south of the lake. Besides, when the Lake's level is 904. 60m., second karstic leakage can also be seen in the Köprü Spring located at 1 km west of the lake. Many correlations are prepared between the water volume of the Kovada Lake and the flow the Gökpınar Spring. There has been a linear relationship between two components. In the Gökpınar spring the value of water leakage is 0.534 m3/sec. when the lake's level is 904.50m. The recharge value of the groundwater in the Kovada Lake is found to be 10.5x10 m3/year after water balance studies. Besidesfithe annual lake's recharge is also found to be 27.5x10 m3 and discharges 28.8x10 m3. 5. THE SUGGESTED STUDIES OF REHABILITATION RELATED TO THE KOVADA LAKE The water loses in the lake is determined as 1.3x10 m3 after the annual water balance of the lake is prepared. This value is bigger during the summer seasons. But there is a water increase in the lake during the winter seasons. In this study, further water addition is suggested when the lake's is lower than 904.50 meters in the summer seasons. This water can be obtained from the channel which connects Eğirdir Lakes and hydropower plants. Additional water value is 3.7x10 m3 between Ouly and January during the seven months. However, 2.4x10 m3 water increase will be in the lake from February to Oune for five months. XI KARST HYDROGEOLQGY The investigation area is located in the mast impartant and the widest Taurus Karst Belt. The limestones and the dolomites of the allochthonaus Antalya Complex and autocthonous limestones and conglomerates of the Aksuçay formation which have carbonate pebbles within the carbonate matrix identify as soluble rock units; wheras the deposits of the Ispartaçay formation such as radiolarite ribbon chert, sandstone and the rocks of the Akdoğan formation, K'xzil- dağ Harzburgite are identified unsaluble rack units. The limestones, dolomites and conglomerates in the area can be seen as the aquifers. But these aquifers are not one continuous aquifer having the same recharges and discharges. The aquifers are baundaried by the tectonical features or different impermeable rack units. The hydragealagical units have been limited by the regional tectonical effects. As a result, it is determined that the karstif ication is controlled by tectonic and all hydragealagical units in the region is limited by the tectonic effects. The aquifers in this hydragelagical units are named as the Dulup, the Direşkene the Kavada-Gokpmar and the Çandır Unit. k. HYDROGEOLOGY OF THE KOVADA LAKE The mast important water locality in the area is the Kovada Lake. The lake located tectonically in the karstic limestones and dolomites, is a small mountaion lake with about 8, square kilometers surface and a water volume of 17x10 cubic meters at lake elevation 904.00 meter. The deepest point of the lake is about k meters. The lake awed its existance mostly ta the surface inflow from the Eğirdir Lake. There is a hydraulic head differential of about 11 meters between two lakes, Before 1968, the water from the Eğirdir Lake was flawing into the Kovada Lake through a natural channel, After 1968, the flow was regulated, the channel was partly lined, and the water volumes permitted to the enter the lake were controlled by the demand of the hydrapower plants Kovada I and Kovada II. Until 1976, the Kovada Lake uıas only temporary recipient to mater; it served as a regulatory storage. The Eğir dir Lake water entered the lake by one channel and was discharged by another channel leading to the hydropower plants. So a surplus of water from the Eğirdir Lake was discharged to Kovada Lake in order to keep the lake levels steady. However in 1976, instead of entrance and exit channel, a by-pass was excavated so that the Eğirdir Lake water flows directly to the hydropower plants. That is why in recent years the lake dried during the summer seasons since 1976. In this study. 50 sinkholes which cause water leakages around the coast of the lake were found. These water leakages origination from the sinkholes can be seen in the Gökpınar Spring located at 5 kms south of the lake. Besides, when the Lake's level is 904. 60m., second karstic leakage can also be seen in the Köprü Spring located at 1 km west of the lake. Many correlations are prepared between the water volume of the Kovada Lake and the flow the Gökpınar Spring. There has been a linear relationship between two components. In the Gökpınar spring the value of water leakage is 0.534 m3/sec. when the lake's level is 904.50m. The recharge value of the groundwater in the Kovada Lake is found to be 10.5x10 m3/year after water balance studies. Besidesfithe annual lake's recharge is also found to be 27.5x10 m3 and discharges 28.8x10 m3. 5. THE SUGGESTED STUDIES OF REHABILITATION RELATED TO THE KOVADA LAKE The water loses in the lake is determined as 1.3x10 m3 after the annual water balance of the lake is prepared. This value is bigger during the summer seasons. But there is a water increase in the lake during the winter seasons. In this study, further water addition is suggested when the lake's is lower than 904.50 meters in the summer seasons. This water can be obtained from the channel which connects Eğirdir Lakes and hydropower plants. Additional water value is 3.7x10 m3 between Ouly and January during the seven months. However, 2.4x10 m3 water increase will be in the lake from February to Oune for five months. XI KARST HYDROGEOLQGY The investigation area is located in the mast impartant and the widest Taurus Karst Belt. The limestones and the dolomites of the allochthonaus Antalya Complex and autocthonous limestones and conglomerates of the Aksuçay formation which have carbonate pebbles within the carbonate matrix identify as soluble rock units; wheras the deposits of the Ispartaçay formation such as radiolarite ribbon chert, sandstone and the rocks of the Akdoğan formation, K'xzil- dağ Harzburgite are identified unsaluble rack units. The limestones, dolomites and conglomerates in the area can be seen as the aquifers. But these aquifers are not one continuous aquifer having the same recharges and discharges. The aquifers are baundaried by the tectonical features or different impermeable rack units. The hydragealagical units have been limited by the regional tectonical effects. As a result, it is determined that the karstif ication is controlled by tectonic and all hydragealagical units in the region is limited by the tectonic effects. The aquifers in this hydragelagical units are named as the Dulup, the Direşkene the Kavada-Gokpmar and the Çandır Unit. k. HYDROGEOLOGY OF THE KOVADA LAKE The mast important water locality in the area is the Kovada Lake. The lake located tectonically in the karstic limestones and dolomites, is a small mountaion lake with about 8, square kilometers surface and a water volume of 17x10 cubic meters at lake elevation 904.00 meter. The deepest point of the lake is about k meters. The lake awed its existance mostly ta the surface inflow from the Eğirdir Lake. There is a hydraulic head differential of about 11 meters between two lakes, Before 1968, the water from the Eğirdir Lake was flawing into the Kovada Lake through a natural channel, After 1968, the flow was regulated, the channel was partly lined, and the water volumes permitted to the enter the lake were controlled by the demand of the hydrapower plants Kovada I and Kovada II. Until 1976, the Kovada Lake uıas only temporary recipient to mater; it served as a regulatory storage. The Eğir dir Lake water entered the lake by one channel and was discharged by another channel leading to the hydropower plants. So a surplus of water from the Eğirdir Lake was discharged to Kovada Lake in order to keep the lake levels steady. However in 1976, instead of entrance and exit channel, a by-pass was excavated so that the Eğirdir Lake water flows directly to the hydropower plants. That is why in recent years the lake dried during the summer seasons since 1976. In this study. 50 sinkholes which cause water leakages around the coast of the lake were found. These water leakages origination from the sinkholes can be seen in the Gökpınar Spring located at 5 kms south of the lake. Besides, when the Lake's level is 904. 60m., second karstic leakage can also be seen in the Köprü Spring located at 1 km west of the lake. Many correlations are prepared between the water volume of the Kovada Lake and the flow the Gökpınar Spring. There has been a linear relationship between two components. In the Gökpınar spring the value of water leakage is 0.534 m3/sec. when the lake's level is 904.50m. The recharge value of the groundwater in the Kovada Lake is found to be 10.5x10 m3/year after water balance studies. Besidesfithe annual lake's recharge is also found to be 27.5x10 m3 and discharges 28.8x10 m3. 5. THE SUGGESTED STUDIES OF REHABILITATION RELATED TO THE KOVADA LAKE The water loses in the lake is determined as 1.3x10 m3 after the annual water balance of the lake is prepared. This value is bigger during the summer seasons. But there is a water increase in the lake during the winter seasons. In this study, further water addition is suggested when the lake's is lower than 904.50 meters in the summer seasons. This water can be obtained from the channel which connects Eğirdir Lakes and hydropower plants. Additional water value is 3.7x10 m3 between Ouly and January during the seven months. However, 2.4x10 m3 water increase will be in the lake from February to Oune for five months.