D.S.İ. Kalecik Barajı su kaçaklarını yönlendiren mühendislik jeolojisi etmenleri

Abstract

Ceyhan nehrinin Adana-Osmaniye ilçesi yakınındaki bir kolu olan Kalecik deresi üzerine, sulama suyu temini amacıyla 77 m. yüksekliğinde kaya dolgu tipinde Kalecik Barajı inşaa edilmiştir. Baraj yerinde Kalecik Deresinin drenaj alanı 145 km^, ortalama akımı 1.6 m-Vs dir. Kalecik Barajının sağ yamacı ve göl alanının bir kısmı melanj içerisindeki kireçtaşı bloğu üzerindedir. Paleojen yaşındaki blok tabandan itibaren kiltaşı-siltaşı- kumtaşı (eı)/ konglomera-ki 1 li kireçtaşı {&2^ ' kumtaşı- kiltaşı-kumlu kireçtaşı (63) ve kireçtaşından (64) oluşmuştur. Baraj gölünden olan kaçaklar bu kireçtaşlarıyla mansaba iletilmektedir. Baraj inşaatı sırasında baraj gölünden olabilecek kaçakları önlemek amacıyla sağ sahilde 200 m uzunluğunda 60 m derinliğinde enjeksiyon perdesi yapılmıştır. Su tutulduktan sonra mansapta kaynaklar görülünce aynı zon onarılmaya çalışılmıştır. Onarım en jeksiyonlarıyla da kaçaklar önlenemeyince baraj gölünden kaçan suların hareket yönünü belirlemek amacıyla sondaj kuyuları açılmış, açılan kuyularda yeraltı su seviyeleri ölçülmüş, kaynaklarda düzenli akım ölçümleri, su kimyası çalışmaları ve izleme deneyleri yapılmıştır. Baraj inşaatı sırasında inşaa edilen enjeksiyon perdesinin bölgesel olarak geçirimsiz ofiyolit melanja kadar inmediği tesbit edilerek mevcut perdenin derinleştirilmesine karar verilmiştir. Gövdeyle dolusavak arasında ofiyolitli melanj içerisinde 10 m ilerleyecek ve of iyolit-kireçtaşı kontağından boşalan K-5 kaynağının kotuna inecek şekilde projelendirilen perdenin inşaatı tamamlandıktan sonra, baraj gölü dolarken sondaj kuyu ve kaynak rasatlarına devam edilmiştir. Göl; 502,5,505,5 ve 526 m kot larındayken izleme deneyleri yapılmış, karst sisteminin davranışı ve derin enjeksiyon perdesinin sağladığı faydalar araştırılmış, buna bağlı olarak su kaçaklarının değerlendirilmesi yapılmıştır.

Kalecik Dam is built on the Kalecik Creek with the aim of irrigation. Kalecik Creek is formed by the springs and brooks that take place on the hills found in the southeast of the inspected area and run towards the north-wes direction. At the location of the dam, the drainage area of the Kalecik Creek is 145 km2 and average flow is 1.6 m3/s. Kalecik Dam location is 27 km east of Osmaniye Country. On the 20 th km of Osmaniye-Bahçe Highway, at the Kızıldere village-Hasanbeyli cross, a road leads to the dam area. This distance between Adana and Kalecik dam area is 112 km. The 2 km long unpaved road that leads to the axel section of the dam may caused hardship in travelling during the rainy season. In the inspection area, Mediterranean climate is dominant. The summers are hot and dry and the winters are warm and rainy. Snowing is insignificant. The Kalecik Dam is built in the style of rock-filling at the height of 77 m. The dam axel lenght is 194 m and maximum water level is 533 m. Earlier in the year of 1970, K. Akdere has complied a report on the dam and prepared a map in the scale of 1/25.000. Also in the year 197 6, VI i N. Yavuz has written a report on the dam and prepared a geological map in the scale of 1/1000. From the lowest part of the Paleogene, el (claystone, silstone, sandstone), e2 (Conglomerate, clayey limestone), 63 (standstone claystone, sandy limestone) and e4 (limestone) have formed. The seepages from the reservoir area are taken to the downsteam with the help of the limestone. This unit goes on by getting thicker under the conglomerates of Kalecik towards the right clayish slope. On the right bank, a grout curtain which is 200 m long and 60 m deep was built to prevent the probable seepages from the reservoir area during the construction. After the water had been kept, the zone was tried to be repaired when the sources were seen around the downstream. _ When the seepages couldn't be prevented by the help of repair grouts, karstic investigation drills were opened to find out the movement direction of the water from the reservoir area. Later, in these drills ground water. Level and regular flow of the sources were measured. Also, water chemistry was studied and dye tests were made. Vlll The units in the inspection area, based on the land surveys made and drilling results arciheved, are lined up as follows: miocene conglomerates, basalt, paleogneic limestone and ophiolite. On Mount Amanos, there is the sedimentation of carbonate which is thicker than 1000 m. On this sedimentation of carbonate, you can see the series which carry ophliolitic materials and which have complicated inner parts with in characteristics of melange. These series have an unconformity contacts. The right slope of Kalecik Dam and some parts of the reservoir area are above the blocks of limestone which is in melange. The layer thicknesses of the paleogneic limestone in the inspection area differ between 7 to 40 cm. They are of white-grey color and have the texture of cryptocrystalline. In their cracks, secondary calcit seams are located. The paleogenic limestone are seen at Kalecik conglomerate and at uncovered sections. In the limestones, sandstones levels are increased. The miocene conglomerates generally are of red color. The red color in the cement are caused by FeO. The pebblestones basicly are basic and ultrababisc. The limestone, from place to place, contains pebblestones. The Kalecik Dam is constructed on the ophiolite rocks group and the limestone layer IX that covers it. The left bank of the Kalecik Dam takes place on the ophiolite rocks and the right bank on the limestones. The ophiolite celling topography not being smooth, shows different elevations from place to place. The ophiolite-limestone contact on the right bank, while being at an elevation of 520 m, is 4 60 m in the drill numbered SK-9 and are raised to 480 m in the drills numbered SK-11 and SK-16. As going upsteam towards the fountainhead from the dam axel the ophiolite ceiling is raise and the thickness of the limestone Is decreased. The Kalecik Dam grout curtain injection works have been carried on for 3 times at different times. Namely, these are, the 1st grout curtain injection done at the time of construction, the 2nd one being the one done in the year 1985 and the 3 rd one being the one done in the year 1989. In the grout curtain injections that have been carried, 825 tons of cement, 4.8 tons of sand, 0.2 ton of natrium silicate are used. 99% of the mixture volume is consisted of water. In the Kalecik Dam, there are 5 important springs. Some of these have come outaf ter the injection works. The Kl spring flows thourgh the deviation tunnel at a discharge rate of 80 lt/sec when the ram water level reaches a height of 4 95.35 m., the K2 spring flows through the derivation tunnel of the left bank at a discharge rate of 3 lt/sec. The K2 spring comes out through the limestones layer. When the lake level has reached 504 meter, the discharge rate of the spring has increased. The K3 spring is coming out from the limestone and sandstone mudstones contact. The K4 spring is obseverd when the lake level reaches a height of 520 m. and is coming out the contact of limestones and sanstones-mudstones. When the dam lake level has reached 527 m, its discharge rate has increased to 80 lt/sec. The K5 spring comes out the ophiolite rocks and limestones contact and till the lake level reaches 514 m. its discharge rate stays fixed at 40 lt/sec and only increases after 514 meters. In order to determine the water leakege from the dam lake, dye-tests are carried at levels of 502 m, 504 m. and 526 m. The dye tests carried out while the lake level wreat 502 and 52 6 meters before the group curtain injection works, have been repeated at 504 meters after the grout curtain injections work. Upon copletion of these, the benefits achieved by the grout curtain injection works have been examined.