Debi-seviye izleme ve taşkın uyarı maksatlı gerçek zamanlı nehir gözlem istasyonu imalatı: Aşağı Sakarya Nehri uygulaması
Manufacturing of a real-time river monitoring station for discharge-level monitoring and flood warning: Lower Sakarya River application
Yazar: FATMA DEMİR
Danışman: DOÇ. DR. OSMAN SÖNMEZ
Sakarya Üniversitesi / Fen Bilimleri Enstitüsü / İnşaat Mühendisliği Ana Bilim Dalı / Hidrolik Bilim Dalı
Derece: Doktora, 2024
Konu: İnşaat Mühendisliği = Civil Engineering

Özet:
Bu tez çalışması kapsamında, köprü kesitlerinde ultrasonik mesafe sensörü kullanılarak, insan gücüne ihtiyaç duymadan doğru ve sürekli gerçek zamanlı debi-seviye ölçümleri yapabilen bir nehir gözlem istasyonu geliştirilmiştir. Bu sistem sayesinde nehir üzerindeki hidrolik analizler için güvenilir veri sağlanmış ve olası taşkınlar için erken uyarı sistemi oluşturularak taşkın risklerinin en aza indirilmesi hedeflenmiştir Ultrasonik mesafe sensörleriyle ölçülen seviye verileri, köprü kesitlerinde kritik düzeylere ulaştığında ilgili kişi ve kurumlara uyarı ve bilgi mesajları gönderebilen bir sistem oluşturulmuştur.
Gerçek zamanlı nehir gözlem istasyonu entegre elemanları, dakikada iki kez nehir seviyesini ölçen ultrasonik sıvı seviye sensörü, Sim 800L GSM modülü, akü, mikroişlemci kartı, RS485 dönüştürücü ve entegre güneş panelinden oluşmaktadır. Bu sistemde, güneş paneli ve MPPT solar enerji kontrol ünitesi sayesinde harici bir besleme kaynağına ihtiyaç duymadan enerji bağımsızlığı sağlanmıştır. Ölçüm verileri GSM modülü aracılığıyla merkezi bir sunucuya aktarılmakta ve web sayfası üzerinden anlık olarak erişilebilmektedir. 
Entegre sistemin yazılım kısmında, açık kaynak kodlu Arduino yazılımı kullanılmıştır. Ultrasonik mesafe sensöründen alınan veriler, GSM modülü aracılığıyla internet üzerinden sunucuya iletilmektedir. Bu işlemler, Arduino IDE kullanılarak kodlanmıştır. Verilerin alınması ve görüntülenmesi için PHP dili kullanılmıştır. Arduino platformu, sensörlerden gelen dijital ve analog sinyalleri işlemek için tercih edilmiştir.
Tasarlanan gerçek zamanlı nehir gözlem istasyonu, laboratuvar ve arazi kalibrasyonunun tamamlanmasının ardından Sakarya Nehri üzerindeki Örencik Köprüsü'ne monte edilmiştir. Sensör kabininin araç geçişlerinden ve dış koşullardan etkilenmemesi için özel olarak tasarlanan destek yapısı ve sensör yuvası, sensörün güvenli bir şekilde yerleştirilmesini sağlamıştır.
Gerçek zamanlı akım gözlem istasyonu tarafından toplanan veriler, Doğançay HES 1 verileri ile karşılaştırılmış ve %99 doğrulukla uyum sağladığı belirlenmiştir. Hesaplanan %97.9 determinasyon katsayısı, ölçülen verilerle HES akımlarının büyük bir kısmının açıklandığını göstermiştir. Bu yüksek uyum ile verilerin güvenilirliği ve doğruluğu teyit edilmiştir. 
Tez çalışmasının taşkın modelleme çalışmalarında HEC-RAS programı kullanılarak iki boyutlu hidrolik taşkın hesaplamaları yapılmıştır. Çalışma alanındaki taşkın yayılımları, taşkın tekerrür debileri kullanılarak modellenmiştir. Tez çalışması kapsamında imal edilen akım gözlem istasyonu ile nehir yatağı içerisinde ölçüm yapılan periyottaki en yüksek debi değeri ve 2, 5, 10, 25, 50, 100, 500 yıllık tekerrürlü debi değerleri belirlenmiş ve model oluşturulmuştur. Bu modelerden elde edilen veriler, taşkın derinlik, hız ve tehlike haritalarının oluşturulması amacıyla coğrafi bilgi sistemi yazılımlarından biri olan ArcGIS programına aktarılmıştır.
Bu tez çalışması ile geliştirilen sistemin web sayfası arayüzü üzerinden, gerçek zamanlı debi-seviye bilgilerine ve farklı tekerrür sürelerine ait HEC-RAS programı kullanılarak oluşturulan taşkın yayılım haritalarına erişim sağlanmıştır. Bu sayede, kullanıcılar anlık verileri takip edebilir ve olası taşkın risklerini değerlendirebilir. Sistem, taşkın yönetimi ve erken uyarı süreçlerinde, taşkın zararlarının en aza indirilmesinde kritik bir rol oynayacaktır.

Abstract:
In this thesis, a river monitoring station has been developed that can perform accurate and continuous real-time discharge-level measurements at bridge cross-sections using an ultrasonic distance sensor, without the need for human intervention. This system provides reliable data for hydraulic analyses on the river and aims to minimize flood risks by establishing an early warning system for potential floods. The level data measured with ultrasonic distance sensors form a system that can send alert and information messages to relevant individuals and institutions when the levels at the bridge cross-sections reach critical thresholds.
The real-time river monitoring station's integrated components include an ultrasonic liquid level sensor that measures the river level twice per minute, a Sim 800L GSM module, a battery, a microprocessor card, an RS485 converter, and an integrated solar panel. In this system, energy independence is achieved without the need for an external power source, thanks to the solar panel and the MPPT solar energy control unit. Measurement data is transmitted to a central server via the GSM module and can be accessed instantly through a web page.
In the software part of the integrated system, open-source Arduino software is utilized. The data collected from the ultrasonic distance sensor is transmitted to the server over the internet via the GSM module. These operations have been coded using the Arduino Integrated Development Environment (IDE). The PHP language has been used for receiving and displaying the data. The Arduino platform is preferred for processing digital and analog signals from sensors.
After completing the laboratory and field calibration, the designed real-time river monitoring station was mounted on the Örencik Bridge over the Sakarya River. A specially designed support structure and sensor housing ensure the sensor cabin is protected from vehicle traffic and external conditions, allowing the sensor to be securely installed. This cabin is designed to protect electronic equipment in a waterproof environment and to minimize malfunctions caused by external factors.
A special protection device has been designed for the sensor cabin stand. This device protects the sensor from falls and is manufactured with a structure that can be moved upwards, allowing for easy removal when necessary. The design has been developed to ensure that there are no obstacles in front of the sensor, to facilitate installation and removal processes. This design supports the effective use of the sensor and minimizes potential problems.
The developed river monitoring station was successfully mounted on the Örencik Bridge over the Sakarya River, and the accuracy of the data obtained has been tested using various methods. The station plays a significant role in flood risk management by making real-time water level and discharge measurements. The calibration of the developed system was meticulously carried out through laboratory and field studies, confirming the accuracy and reliability of the data obtained.
Calibration studies conducted in a laboratory environment were meticulously executed through the integration of manual and automatic measurement techniques. These studies were carried out to make the necessary adjustments to ensure accurate measurements by the sensors. Field calibration studies were conducted at the pipe transmission bridge connected to Hanlı district over the Sakarya River and at the Örencik Bridge where the station was to be installed. At the Örencik Bridge, the distance measured by the sensor was recorded as 1098 cm, while the measurement made with a laser meter was determined to be 1097 cm. This resulted in a margin of error of 0.1%, confirming that the sensor settings were correctly adjusted and the calibration was successful.
The data collected by the real-time streamflow monitoring station were compared daily, hourly, and monthly with the data from Doğançay HES 1 and were found to align with 99% accuracy. The calculated determination coefficient of 97.9% indicates that a significant portion of the measured data can explain the flow rates of the HES. This high conformity confirms the reliability and accuracy of the data.
In the thesis work, a discharge rating curve was developed using regular level measurements taken at the Örencik Bridge section of the Sakarya River from 2022 to 2023 for the river monitoring station constructed. The high determination coefficient (R² = 0.9981) of this curve demonstrates that the curve fits the data very well and accurately represents the relationship between water level and discharge.
For the verification of data from the real-time river monitoring station, values from the 2023 water year were analyzed. It was determined that the annual average water level measured by the river monitoring station, at 2.06 meters, exceeded the average water level of the summer months but fell below that of the spring months. In terms of seasonal discharge variations, the average discharge was 50.71 m³/s, which was above the average discharge value for the autumn months but below that for the spring months.
The 2023 water year values, including water level and discharge measurements, were analyzed alongside the total daily precipitation data obtained from the Turkish State Meteorological Service's station number 17662. During periods of increased rainfall, corresponding rises in water levels and discharge were noted, providing strong validation for the accuracy of these measurements. Particularly during times of heavy rainfall, notable increases in both discharge and water levels were observed. This responsiveness highlights how well the basin reacts to changes in rainfall amounts and illustrates the high degree of alignment between the real-time river monitoring station's measurement data and the hydrological characteristics of the basin.
For the flood modeling in the thesis work, the HEC-RAS software was employed. The necessary digital elevation model and building polygon information for the HEC-RAS program infrastructure were obtained from the Ministry of Environment Urbanization and Climate Change, while the land use map was sourced from the CORINE dataset. Flood discharge calculations for the two-dimensional hydraulic analysis were computed using probability distribution functions. For these calculations, the annual maximum instantaneous peak discharges (YAMA) from the Doğançay station, identified by code E12A021, were utilized. The flood discharges were derived using various distributions, including Normal Distribution, Log-Normal with 2 Parameters, Log-Normal with 3 Parameters, Pearson Type 3, Log-Pearson Type 3, and Gumbel Distribution.
During the thesis work, the flow monitoring station that was manufactured was used to measure the highest discharge value during the measurement period in the riverbed, as well as the recurring discharge values for 2, 5, 10, 25, 50, 100, and 500 years. Models were developed based on these measurements. Data derived from these models were then transferred to ArcGIS, a geographic information system software, for the purpose of creating flood depth, velocity, and hazard maps. This integration facilitated the detailed analysis and visualization of potential flood impacts, enhancing the effectiveness of flood risk management and planning.
This thesis work has developed a system that allows access to real-time discharge-level information and flood inundation maps created using the HEC-RAS program through a web page interface. This enables users to monitor instantaneous data and assess potential flood risks. The system has played a critical role in flood management and early warning processes, significantly aiding in the minimization of flood damages. Through this integrated platform, stakeholders can respond more effectively to emergent flood events, optimizing mitigation strategies based on real-time data and predictive modeling.