Ekolojik açıdan büyük önem arz eden sazlıklı bölgeler (sulak alanlar) hassas bir dengeye sahiptir. Özellikle göç eden kuşlar için önemli bir uğrak ve dinlenme yeri olan bu bölgeler, aynı zamanda içerdikleri zengin besin olanaklarıyla kara ve su canlıları için de önemli bir yaşam alanıdır. Bu bölgelerin korunabilmesi ve sürdürülebilir kullanımı için, mevcut hidrodinamik yapının bilinmesi gereklidir. Sazlıklı bölgelerde gerçekleştirilecek sıcak su deşarjlarıyla ortama eklenen atık suyun davranışının belirlenerek, olumsuz etkilerinin en aza indirilebilmesi bir gerekliliktir. Bu çalışmanın amacı sazlıklı ortama verilen sıcak su deşarjının dalga etkisiyle değişen hız dağılımının tespit edilmeye çalışılmasıdır. Bu amaçla, dalga yüksekliği, başlangıç sıcaklık farkı, deşarj edilen debi ve sazlık olup olmaması bağımsız değişken olarak kabul edilmiş ve bu şartlarda 17 adet kontrollü deney gerçekleştirilmiştir. Ölçülen parametreler; sıcaklık, hız, dalga yüksekliği ve dalga periyodudur. Deneysel çalışma 22×1×0.5 m boyutlarında bir kanalda gerçekleştirilmiştir. Akım hızları Vectrino+ akustik doppler hızölçer ile 50 Hz sıklığında kaydedilmiş ve en düşük kayıt süresi 1 dakika olarak belirlenmiştir. Sıcaklıklar Pt100 tipi 19 adet termometre ile ölçülmüştür. Sonuç olarak hem sazlıklı hem de sazlıksız ortamlar için dalga yüksekliği-hız dağılımı bağıntıları istatistiksel bir yaklaşımla elde edilmiştir. İstatistiksel yaklaşımda çoklu regresyon analiz yöntemi kullanılmıştır. Söz konusu bağıntılar bağıl sıcaklık, boyutsuz hız ve bağıl derinlik parametrelerinin fonksiyonları olarak verilmiştir. Elde edilen fonksiyonların istatistiksel açıdan yeterli hassasiyette olduğu görülmüştür. Sazlıksız ortamdaki hız değerleri klasik yöntemlerle hesaplandıktan sonra elde edilen bu fonksiyonlarla karşılaştırılarak sazlıklı ortamdaki dağılım elde edilebilmektedir. Anahtar Kelimeler: Sıcak su deşarjı, sazlıklı ortam, hız dağılımı. Ecologically important vegetated areas bear a tender equilibrium. These areas are specifically places for birds and the great habitats for animals as well, since these places are very wealthy when it comes to nutrients. Hydrodynamic structures of these places should be known in order to maintain a sustainable development. Thus, this study is done to reveal the hydrodynamic structures of vegetated areas and the behaviour of waste water with thermal water discharges, and eventually to reduce the negative effects of this phenomenon. The changes in the characteristics of thermal water discharges which are induced by vegetation at the receiving environment are examined with the help of an experimental study. Velocity and dispersion coefficients were tried to be determined with previously conducted studies. In addition, drift forces caused by the changes occurred in the flow by one plant or a plant group were tried to be determined. In this study, wave height, temperature difference, flow rate of the discharge, and the existence of vegetation are chosen as independent variables, and 17 sets of experiments are conducted. Temperature, velocity, wave height and wave period are the measured parameters during the experiments. Experiments are conducted in a 22×1×0.5 m dimensioned flume. Flow velocities are measured at least record is 1 minute long. Furthermore, temperatures are recorded with 19 "Pt100" type thermometers. As a result, a velocity dispersion function related to varying wave heights are derived with a statistical approach for vegetated and non-vegetated environments. Multiple regression method is used in the statistical approach and the aforementioned functions are given for the parameters which are relative temperature, dimensionless velocity and relative depth. Note that, multiple regression method was previously used for obtaining the dispersion coefficient and the flow conditions. The thermal water gradient affected by vegetation with respect to the mentioned variables was tried to be determined in the flow field.Excess temperatures for the vegetated experiments were chosen as 5 and 15 oC, where the flow rate was 15 l/min and the generated waves in the flume were 2.5, 5 and 7 cm of height for each temperature value. The experiments of non-vegetated case were carried out with the flow rate values; namely, 10 and 15 l/min for the same wave conditions. Recorded velocity values were divided by wave group velocity (H/T). Multiple regression analyses conducted for velocity are valid for the third and the fourth zone, if the temperatures of the first and the second zone are assumed to be constant. Consequently for the vegetated case experiments, the equation U/(H/T) =3.4457*z/zo - 0.00004*L - 0.0066 DT - 0.0329 Q was obtained as a result of the multiple regression analysis carried out for U/(H/T). And the result of the multiple regression analysis carried out for the non-vegetated case comes out with the equation U/(H/T) =2.7662*z/zo - 0.0001*L - 0.0080*DT - 0.0181*Q. The difference between these two equations reveals the change in the flow affected by the vegetation. This difference may be computed by a subtraction operation between these two equations which leads to the equation [U/(H/T)]s-[ U/(H/T)]= 0.6795 z/zo+ 0.00006*L + 0.0014*DT- 0.0148*Q. Here the index S expresses the result of the vegetated case experiment. The variables of the newly given equation come out as relative depth, horizontal distance, temperature difference between the receiving environment and the discharged fluid, and the flow rate of the discharge, all of which should already be known by any engineer who works on subjects related to thermal water discharge. Therefore, determination of the change in temperature and the velocity gradient becomes a simple issue. Note that, wave steepness and wave period are on the right hand side of the recommended equation (wave steepness is obtained by dividing significant wave height by significant wave period as known), and it is clear that if one knows the design wave height and wave period, it becomes possible to compute the vegetated case velocities after the determination of non-vegetated case velocities with the help of the given equations. Obtained results are valid for the scope and conditions of this study, and more general approaches should be produced by future studies on this issue. Specifically, investigating the effect of variation of the vegetation properties on the mentioned phenomenon can be recommended. Keywords: Thermal discharge, vegetation, velocity variation.
