Melike Gurel

Groundwater Pollution and Quality Monitoring Approaches at the European Level

The authors investigate the sources and processes of groundwater contamination and their assessment within the Drivers-Pressures-State-Impact-Response (DPSIR) framework. Naturally occurring substances, trace elements, radionuclides, nutrients, and salt (sodium chloride) are reviewed with emphasis on the assessment of the natural background load. Some synthetic substances are also considered, these being petroleum hydrocarbons, chlorinated aliphatics, pesticides and organic-waste contaminants. Newly emerging contaminants cannot be described within the DPSIR; therefore monitoring approaches and indicators of contamination are discussed in order to propose improved monitoring plans that combine physical, chemical and biological indicators and combine science with policy.

Evaluating the impact of climate change on groundwater resources in a small Mediterranean watershed.

Western Mediterranean Region of Turkey is subject to considerable impacts of climate change that may adversely affect the water resources. Decrease in annual precipitation and winter precipitation as well as increase in temperatures are observed since 1960s. In this study, the impact of climate change on groundwater resources in part of Köyceğiz-Dalyan Watershed was evaluated. Evaluation was done by quantifying the impacts of climate change on the water budget components. Hydrological modeling was conducted with SWAT model which was calibrated and validated successfully. Climate change and land use scenarios were used to calculate the present and future climate change impacts on water budgets. According to the simulation results, almost all water budget components have decreased. SWAT was able to allocate less irrigation water because of the decrease of overall water due to the climate change. This resulted in an increase of water stressed days and temperature stressed days whereas crop yields have decreased according to the simulation results. The results indicated that lack of water is expected to be a problem in the future. In this manner, investigations on switching to more efficient irrigation methods and to crops with less water consumption are recommended as adaptation measures to climate change impacts.

Use of Remotely Sensed Data for Analysis of Land-Use Change in a Highly Urbanized District of Mega City, Istanbul

The study forms an example on monitoring and understanding urban dynamics by using remotely sensed data. The selected region is a rapidly urbanizing district of the mega city Istanbul, Gaziosmanpasa, whose population has almost doubled between years 1990 and 2000. The significance of this district besides its urban sprawl is that 61% of its land lies within the boundaries of an important drinking water reservoir watershed of the mega city, the Alibeykoy Reservoir. The land-use/cover changes that has occurred in the years of 1987 and 2001 are analyzed by utilizing a variety of data sources including satellite images (Landsat TM image of September 1987 and Landsat ETM+ image of May 2001), aerial photographs, orthophoto maps, standard 1:25000 scale topographic maps, and various thematic maps together with ground survey. Land-use changes are analyzed on the basis of protection zones of the reservoir watershed and the conversion of bare land and forests to settlements are clearly observed despite the national regulation on watershed protection. The decline of forests within the protection zones was from 69% to 63.6% whereas the increase in settlements was from 0.8% to 3.9%. The associated impact of establishing new residential sites with insufficient infrastructure is then linked with the water quality of the reservoir that has already reached to Class III characteristics regarding the recently revised national legislation stating that any class exceeding Class II cannot be used as a drinking water supply that in turn, had consequences on regulating the water services such as upgrading the existing water treatment plant. The paper aims to help the managers, decision-makers and urban planners by informing them of the past and current land-use/cover changes, to influence the cessation of illegal urbanization through suitable decision-making and environmental policy that adhere to sustainable resource use.

Occurrence of THM and NDMA precursors in a watershed: Effect of seasons and anthropogenic pollution

In pristine watersheds, natural organic matter is the main source of disinfection by-product (DBP) precursors. However, the presence of point or non-point pollution sources in watersheds may lead to increased levels of DBP precursors which in turn form DBPs in the drinking water treatment plant upon chlorination or chloramination. In this study, water samples were collected from a lake used to obtain drinking water for Istanbul as well as its tributaries to investigate the presence of the precursors of two disinfection by-products, trihalomethanes (THM) and N-nitrosodimethylamine (NDMA). In addition, the effect of seasons and the possible relationships between these precursors and water quality parameters were evaluated. The concentrations of THM and NDMA precursors measured as total THM formation potential (TTHMFP) and NDMA formation potential (NDMAFP) ranged between 126 and 1523μg/L THM and <2 and 1648ng/L NDMA, respectively. Such wide ranges imply that some of the tributaries are affected by anthropogenic pollution sources, which is also supported by high DOC, Cl(-) and NH(3) concentrations. No significant correlation was found between the water quality parameters and DBP formation potential, except for a weak correlation between NDMAFP and DOC concentrations. The effect of the sampling location was more pronounced than the seasonal variation due to anthropogenic pollution in some tributaries and no significant correlation was obtained between the seasons and water quality parameters.

Application of Watershed Modeling System (WMS) for Integrated Management of a Watershed in Turkey

Watershed models, that enable the quantification of current and future pollution loading impacts, are essential tools to address the functions and conflicts faced in watershed planning and management. In this study, the Watershed Modeling System (WMS) version 7.1 was used for the delineation of boundaries of Koycegiz Lake-Dalyan Lagoon watershed located in the southwest of Turkey at the Mediterranean Sea coast. A Digital Elevation Model (DEM) was created for one of the major streams of the watershed, namely, Kargicak Creek by using WMS, and DEM data were further used to extract stream networks and delineate the watershed boundaries. Typical properties like drainage areas, characteristic length and slope of sub-drainage areas have also been determined to be used as model inputs in hydrological and diffuse pollution modeling. Besides, run-off hydrographs for the sub-drainages have been calculated using the Rational Method, which produces valuable data for calculating the time variable inflow and input pollution loads to be further utilized in the future water quality models of the Creek. Application of WMS in the study has shown that, it is capable to visualize the results in establishing watershed management strategies.

Application of Water Quality Modelling as a Decision Support System Tool for Planned Buyuk Melen Reservoir and Its Watershed

Istanbul, the largest metropolis of Turkey and one of the most crowded metropolises in the world, is facing the risk of water scarcity. Analyses indicated that one of the alternative solutions coping with this problem is water transfer from a watershed that is located outside the administrative boundaries of Istanbul. Due to its water potential and relatively less degraded water quality, Buyuk Melen Watershed was considered to be the most feasible option. As the result of analyses, State Hydraulic Works (DSI) has planned construction of a reservoir in the Buyuk Melen Watershed to supply the required amount of water for Istanbul also in low flow seasons. Since the reservoir will be located at the downstream region of the watershed, its water quality will be affected by human-induced activities, thus measures need to be taken to prevent pollution prior to reservoir construction. Quantifying the response of the planned reservoir to external pollution loads is an important step in the planning and management of the watershed. Mathematical modelling is a useful tool for estimating the future water quality and understanding the possible responses of the reservoir to various pollution loads. In this study, a water quality model capable of simulating hydrodynamics, transport and water quality in reservoirs is used for preliminary estimation of possible impacts of several management options in the watershed. Model results indicated that, all of the point sources in the watershed must be controlled by advanced wastewater treatment and should be diverted from the streams and the planned reservoir. Model results also indicated that reduction of agricultural diffuse loads by 30–40% is expected to have a perceptible improvement of reservoir water quality.

Efforts towards setting eutrophication assessment criteria for coastal marine ecosystems

Eutrophication of coastal marine environments is a widespread and transboundary problem necessitating consideration of measures to conserve and restore the marine environments that have been adversely affected. As of now, there exist no criteria set for eutrophication of coastal marine waters due to the difficulty to establish single national/international assessment criteria for eutrophication applicable to all coastal waters with different geographic and climatic conditions. However, there appear to be a number of joint and integrated studies among coastal countries to harmonise the outcomes of their scientific research and monitoring activities that might change the natural attributes of the environment. The common findings may then be utilised to develop guidelines on establishing eutrophication criteria together with application of policies and strategies. This study attempts to review the recent efforts of certain groups gathered together and of some countries to develop and improve approaches for assessment of eutrophication in coastal marine waters. Studies of OSPAR Commission, USEPA, and Australia and New Zealand related councils, will also be referred to.

Urban wastewater treatment plants and reuse potential in Turkey: selected examples from the western cities

The present study refers to the outcomes of a detailed survey on the current situation of Turkish Urban Wastewater Treatment Plants (UWWTPs). The survey covers the identification of the population served by UWWTPs, presentation of the current technologies (physical, biological and advanced) applied in the countrys UWWTPs, prevailing effluent disposal criteria, detailed assessment of UWWTPs selected from the Western part of Turkey representing highly urbanised and industrialised districts, and elucidation of needs for upgrading the selected UWWTPs to comply with the current discharge standards and irrigation water quality criteria. Following an extensive data collection and evaluation step, Turkeys most recent situation in the number of UWWTPs, effluent produced in Turkish municipalities both quantity-and quality-wise, urban wastewater treatment types and disposal methods as well as reuse potential of treated urban wastewater have been presented and discussed.

An overview of integrated and interdisciplinary studies on conservation of a coastal lagoon system in Turkey

This paper presents part of the results of ongoing integrated and interdisciplinary studies conducted at a vulnerable coastal lagoon system with the aim of protecting it from further anthropogenic pollution. The target area is in southwestern Turkey, consisting of a lake that joins the Mediterranean Sea via a lagoon channel system. Land resources in the watershed are identified, including all the elements of the physical environment that influence potential land‐use, and are illustrated by the application of geographical information systems through mapping and visualization of various thematic layers of land. This study will enlighten those working on lagoon watersheds aiming at conservation of natural resources since it states the results of the studies conducted so far through various disciplines, and presents how data are utilized by the groups in an integrated manner. Based on the available data, pre‐modelling studies on hydrodynamic modelling and on water quality modelling are also referred. Identification of a watershed depends on gathering satisfactory data, which will further be used to establish sustainable development and management plans, apart from utilizing the obtained data for watershed and hydrodynamic modelling approaches and to better understand such complex systems.

Land-Based Sources, Water Quality and Management

ANGHELUTA VADINEANU1, BRENDA RASHLEIGH2, MELIKE GUREL3, ALPASLAN EKDAL3, AMIR ALIYEV9, ANGEL PEREZ RUZAFA4, CIǦDEM TAVŞAN3, ELENA PREDA1, ERIC MASSON5, EUGENIUSZ ANDRULEWICZ6, MARS AMANALIEV, NUR FΙNDΙK HECAN7, OTUZBAY GELDIYEW10 AND SOFIA GAMITO8 1 Department of Systems Ecology and Sustainability, University of Bucharest, Romania 2 U.S. Environmental Protection Agency, Athens, Georgia, USA 3 Environmental Engineering Department, Istanbul Technical University, Turkey 4 Fac. Biologia. Universidad de Murcia, Spain 5 University of Sciences and Technologies of Lille, France 6 Sea Fisheries Institute, Gdynia, Poland 7 Tubitak, Marmara Research Center, Gebze, Turkey 8 IMAR, University of Algarve, Portugal 9 Ministry of Ecology and Natural Resources of the Azerbaijan Republic 10 Institute of Chemistry of State concern “Turkmenhimiya”, Turkmenistan