Sakarya nehri havzasında su kalitesi yönetimi

Abstract

Sosyoekonomik gelişme sürecinde, suyun kısıtlayıcı bir un sur haline gelmemesi amacı ile yapılan su kaynağı planlamalarında belirlenmekte olan yararlı kullanımlar, su kantitesinin yanısıra su kalitesi yönetimini de gündeme getirmektedir. Günümüzde su kalitesi yönetimi ile amaçlanan, sosyoekonomik etkinlikler sonucunda su kaynaklarından günümüzde ve gelecekteki yararlanma olasılıklarının sınırlanmaması için su kalitesini tanımlayan parametrelerin kontrol edilmesidir. Su kaynaklarının kalite yönetimi ile ilgili mevcut bilgilerin değerlendirilmesinde ve ileriye dönük kararların alınmasında matematik modeller önemli bir mühendislik aracı olarak kullanılmaktadırlar. Bu çalışmada ve daha önceki çalışmalarda seçilen matematik modelin kalibrasyonu, doğruluk ve duyarlılık analizleri yapılmış ve modelin güvenirlik ile kullanılabileceği kanıtlanmıştır. Model kullanımı için gereken veriler, havzada başlatılan bir su kalitesi izleme programı çerçevesinde elde edilmiştir. Bu çalışma ile tüm Sakarya Havzası ele alınarak öncelikle günümüz koşullarındaki su kalitesi saptanmış ve daha sonra Porsuk Çayı ile Sakarya Nehri, yararlı kullanımlar açısından değerlendirilerek bu su kaynaklarının istenen amaçlara uygunlukları araştırılmıştır. Daha sonra gelecekteki yararlı kullanımlar belirlenerek, su kalitesinin iyileştirilmesi için alınabilecek önlemlerin su kalitesi üzerine etkileri model yardımı ile araştırılmıştır. Bu bağlamda sürdürülen çalışmada, havzadaki kirletici kaynak potansiyeli ve su kalitesi birlikte değerlendirilerek, çeşitli atıksu kontrol seçenekleri irdelenmiş ve sonuç olarak. amaçlanan kaliteye ulaşılması için ciddi önlemlerin alınması gerektiği anlaşılmıştır. Çalışma sonucunda yapılan değerlendirmede, su kaynakları için ulusal platformda kalite standardı uygulamak yerine, havza boyutunda standart uygulamanın daha akılcı bir çözüm olacağı ve su kalitesi standartlarının havzada amaçlanan çoklu yararlı kullanımlar doğrultusunda belirlenmesi gerekliliği vurgulanmıştır.

Due to the rapid urbanization and industrialization, the increase of water demand for residential, industrial and agricultural areas has been one of the major problems of the last decade. Although Turkey is a country with considerable water resources, only a minor part of the potential is being utilized. In the "Forth Five Year Development Plan" of the 1979 - 1983 period, it has been emphasized that the water resources of the country should be used in a more rational manner. On the other hand, it was pointed out that the water demand can be satisfied by the existing water potential in the national scale into a considerably distant future, if water of adequate quality and quantity for required purposes could be provided at the times and places needed. In this context, a comprehensive management of the national water resources for multi-purpose beneficial use is required. A pilot project for the "Water Quality Management was carried out by the Technical University of Istanbul (I.T.U) and State Hydraulic Works (DSI), 3tft Division. The so-called project was sponsored by "Scientific Affairs Division of NATO" within the scope of the Science for Stability programme. The project was undertaken with the basic understanding that water resources management planning on a national or a regional scale should first ensure that water would not be a limiting factor in economical development. The need for long term economical planning of water resources development was noted and emhasized together with short term requirements. Sakarya River Basin was selected to formulate a management plan for the development of the whole basin and for the consideration of the existing and planned projects in the subbasins. In this framework, system analysis methods were applied for the evaluation and selection of water resources investments, designs and policies. xix The study of water quality, management. in the Sakarya River Basin is particularly interesting as being the first of similar studies in Turkey where quantity and quality have been considered as the major elements in a river basin management effort. Previously reported river management studies did not include quality. Studies in other rivers have not been integrate into comprehensive management projects. As far as pollution control studies are concerned, the project may also be regarded as a continuation of a number of quality oriented projects, previously started and concluded in other parts of Turkey. The main objective of the water quality management project is to evaluate and regulate within a systems approach, all relevant factors and parameters for a beneficial use planning of the basin as far as land use and water use are concerned. In this framework, the project is expected to deliver information to water resources management and to assess the effects of quantitative resources management on water quality. The objective interpreted for the Sakarya River Basin sets the following scope for the project. 1. Pertinent description of the study area. 2. Impact assessment from polluting sources.. development of a unified methodology and procedure related to data collection from polluting sources.. waste characterization, classification and comparative evaluation of industrial polluters.. significance and priority in the evaluation of polluting sources. 3. Determination of the current and future beneficial use depending on. socioeconomic development. planning water resources 4. Evaluation of waste assimilation capacity and actual water quality of the Sakarya River and its confluents. 5. Regulations on Water Quality Management to be projected in Sakarya River Basin on xx . global and. regional scales 6. Water quality model selection for the management approach under consideration. 7. Water quality management. structure evaluation. calibration, verification and sensitivity analysis 9. Evaluation of different scenarios using the calibrated model and defining the management alternative. 10. Estimation of methodology for water quality monitoring and enforcement. Within the context of the project, Porsuk and Sakarya River Basin water quality management studies were the first and second application of these approaches respectively. This study aims to upgrade the water quality of the Basin for the beneficial uses planned. The effect of the preventive actions planned to improve the water quality is examined by a mathematical model tested under a variety of conditions and finally a comprehensive water quality management is applied according to the mentioned approaches for the Basin in its entirety. The study is presented in ten chapters. In the first chapter, a general description of the study area concerning hydrological, topographical, demographical, socioeconomical and climatic characteristics is defined. The basin has a catchment area of 58.000 km2 with a rather varied geological and topographical structure. Sakarya River which originates in Seyitgazi plateau and flows in to the Black Sea, has a total length of 824 km. Porsuk, which is the major confluent, has a total length of 439 km. In the thirth chapter, polluting sources causing water quality problem in the confluents, namely Porsuk and Karasu, are discussed in detail. In Porsuk River Subbasin, the major polluting sources are Kütahya and Eskişehir xxi domestic wastewater and industrial wastewater which originate from Kütahya and Eskişehir Sugar Beet Factories, slaughterhouses, Kütahya Nitrogen Fertilizer Factory, Eskişehir Textile, Wagoon Factory and Organized Industrial District. The total waste load coming from those polluting sources is roughly 400 tons/day of organics, 18 tons /day nitrogen and 1 ton /day of phosphorus, Karasu subbasin is known for its ceramic and tile factories, textile and metal industries situated along Karasu stream. The only polluting source on Sakarya River is Etibank Borax industry situated at the upstream of this river at Kırka region. In the fourth chapter, the current and future beneficial uses in the basin are presented. The Porsuk River is the most important of the surface water resources in the basin. Actually, it serves the purposes of irrigation, industrial water supply and wastewater disposal. DSI State Hydraulic Works has planned the beneficial uses of the Porsuk River primarily as irrigation and as drinking water in the future, and the secondary beneficial uses include industrial water supply, fishing, recreation and wastewater disposal. At the present time, the Porsuk River is heavily polluted when compared with the standards set in the "Water Pollution Control Regulations". Therefore it can not be used for these purposes without any revision. The only regions of Porsuk River acceptible for present beneficial uses are its source, the Porsuk dam exit and the Rivers downstream. Sakarya River itself has a rather good water quality along its main course. In the fifth chapter the previous investigations carried out on the basin and preliminary studies are outlined. Before this study, Porsuk stream water quality was investigated in detail between 1969-1979 and between 1978-1980 by DSI and ITU. During these previous studies, the available data, the monitoring stations, the patterns of various parameters were evaluated. For the present study a detailed data analysis has been carried out during the monitoring program in the period of 1983-1985. Water quality profiles obtained from the evaluation of the results of the measurements during this programme are presented for the stations situated at the upstream and downstream of the Sakarya, Porsuk and Karasu rivers. In the sixth chapter, the basic framework of the water quality management model for the basin is presented. xxn In the seventh chapter, the summary of "works" to be undertaken to choose an appropriate mathematical model that conforms to the objectives of the study and consequently the definition of the model is presented. The model chosen for this study is a simulation model called MODQUAL which is the modified form of the well known model, Qual II. The state variables which were determined due to the characteristics of the rivers and beneficial use considered, are dissolved oxygen, organic matter, nitrogen and phosphorus compounds. In the eighth chapter the calibration and the sensitivity analysis are presented. This study differs from the previous ones by the calibration works and sensitivity analysis which were carried out simultaneously. The parameters which were calibrated by using the model are the flow rate, dissolved oxygen, biochemical oxygen demand, ammonia, nitrate, nitrite and orthophosphate. In the nineth chapter, the effect of various basic measures of improving the actual and future water quality are evaluated. In an attempt to achieve the water quality standards, the effect of dilution was tested. The results have shown that this was not an acceptible solution. The next step was to apply the standards of the "Water Pollution Control Regulations". The results were satisfying except for the nitrogen and phosphorus compounds. The third step, upon which advanced treatment was applied for nutrients, has revealed that all the expected standards were achieved except that for nitrite. Within the next two steps the dry weather flow conditions and the polluting parameters coming from incremental conditions were examined using the mathematical model tested under various conditions. The results revealed that the control of incremental conditions had no effects on the water quality of the stream already polluted by domestic and industrial wastes. In the last chapter, the results obtained are evaluated in first part and in second part, recommendations to the Authorities are made based on these results. It is pointed out that water pollution control standards should be set, not on national scale but on basin scale, according to multi-purpose beneficial use.