Elcin Kentel

Renewable energy potential as an alternative to fossil fuels in Turkey

Abstract Clean, domestic and renewable energy is commonly accepted as the key for future life, not only for Turkey but also for the world. All nations, regardless of their degree of development, are trying to develop and apply technologies that will enable them to use renewable energy sources in the most efficient ways. Turkey’s geographical location has several advantages for extensive use of most of these sources. Because of this and the fact that it has limited fossil fuel resources, a gradual shift from fossil fuels to renewables seems to be serious and the sole alternative for the country. Turkey’s renewable energy source potential and their present use are here evaluated based on the available data.

Identification of the Best Booster Station Network for a Water Distribution System

AbstractA fuzzy decision-making framework (DMF) is combined with a hybrid genetic algorithm–linear programming (GA-LP) optimization approach to determine the best booster station network for a water distribution system. The proposed hybrid GA-LP model simultaneously optimizes two conflicting objectives; namely, minimization of total chlorine injection dosage and the number of booster stations. At the same time, residual chlorine concentrations are kept within desired limits. Adjustment of the relative importance of two conflicting objectives results in different optimal solutions. Selection of the best alternative among these optimal solutions is performed through a fuzzy multiobjective DMF. The proposed DMF allows incorporation of the decision makers’ preferences into the booster station network design. In this study, three fuzzy objectives are selected based on economic, operational, and health-related concerns. The hybrid GA-LP model is applied to a case study, and results show that the proposed method...

An integrated map correlation method and multiple-source sites drainage-area ratio method for estimating streamflows at ungauged catchments: A case study of the Western Black Sea Region, Turkey.

Stream gauges measure the temporal variation of water quantity; thus they are vital in managing water resources. The stream gauge network in Turkey includes a limited number of gauges and often streamflow estimates need to be generated at ungauged locations where reservoirs, small hydropower plants, weirs, etc. are planned. Prediction of streamflows at ungauged locations generally relies on donor gauges where flow is assumed to be similar to that at the ungauged location. Generally, donor stream gauges are selected based on geographical proximity. However, closer stream gauges are not always the most-correlated ones. The Map Correlation Method (MCM) enables development of a map that shows the spatial distribution of the correlation between a selected stream gauge and any other location within the study region. In this study, a new approach which combines MCM with the multiple-source site drainage-area ratio (DAR) method is used to estimate daily streamflows at ungauged catchments in the Western Black Sea Region. Daily streamflows predicted by the combined three-source sites DAR with MCM approach give higher Nash-Sutcliffe Efficiency (NSE) values than those predicted using the nearest stream gauge as the donor stream gauge, for most of the trial cases. Hydrographs and flow duration curves predicted using this approach are usually in better agreement with the observed hydrographs and flow duration curves than those predicted using the nearest catchment.

Evaluation of Heavy Metals and Associated Health Risks in a Metropolitan Wastewater Treatment Plant's Sludge for Its Land Application

ABSTRACT The objectives of this study are to monitor the heavy metal concentrations in sludge samples collected from the Ankara Central Wastewater Treatment Plant (ACWWTP) in Turkey, check if these concentrations comply with the Turkish Regulation (Regulation Regarding the Use of Domestic and Urban Sludges on Soil), and evaluate possible health risks of heavy metals in sludge due to ingestion of sludge by a child. Monthly sludge samples were collected from the ACWWTP during 2012 and analyzed for seven heavy metals (Cd, Cr, Cu, Hg, Ni, Pb, and Zn). According to the results from the study, heavy metal concentrations showed no common seasonal trend. All heavy metal concentrations, except for one sample in which Zn was found to be at the limit value, are below the Turkish Regulation limits. In addition, health risks calculations for the “child ingesting biosolids” pathway, which is one of the most critical pathways identified by the U.S. Environmental Protection Agency (USEPA) for land application, were carried out. Among the seven heavy metals, Pb contributed the most to the cumulative non-cancer health risks throughout 2012. Nevertheless, the results showed that cumulative non-cancer health risks associated with this pathway are within the acceptable non-cancer health risk level suggested by USEPA.

Challenges in development and implementation of health-risk-based soil quality guidelines: Turkey's experience.

Management of contaminated sites is a critical environmental issue around the world due to the human health risk involved for many sites and scarcity of funding. Moreover, clean-up costs of all contaminated sites to their background levels with existing engineering technologies may be financially infeasible and demand extended periods of operation time. Given these constraints, to achieve optimal utilization of available funds and prioritization of contaminated sites that need immediate attention, health-risk-based soil quality guidelines should be preferred over the traditional soil quality standards. For these reasons, traditional soil quality standards are being replaced by health-risk-based ones in many countries and in Turkey as well. The need for health-risk-based guidelines is clear, but developing these guidelines and implementation of them in contaminated site management is not a straightforward process. The goal of this study is to highlight the problems that are encountered at various stages of the development process of risk-based soil quality guidelines for Turkey and how they are dealt with. Utilization of different definitions and methodologies at different countries, existence of inconsistent risk assessment tools, difficulties in accessing relevant documents and reports, and lack of specific data required for Turkey are among these problems. We believe that Turkeys experience may help other countries that are planning to develop health-risk-based guidelines achieve their goals in a more efficient manner.

A pollution fate and transport model application in a semi-arid region: Is some number better than no number?

Fate and transport models are powerful tools that aid authorities in making unbiased decisions for developing sustainable management strategies. Application of pollution fate and transport models in semi-arid regions has been challenging because of unique hydrological characteristics and limited data availability. Significant temporal and spatial variability in rainfall events, complex interactions between soil, vegetation and topography, and limited water quality and hydrological data due to insufficient monitoring network make it a difficult task to develop reliable models in semi-arid regions. The performances of these models govern the final use of the outcomes such as policy implementation, screening, economical analysis, etc. In this study, a deterministic distributed fate and transport model, SWAT, is applied in Lake Mogan Watershed, a semi-arid region dominated by dry agricultural practices, to estimate nutrient loads and to develop the water budget of the watershed. To minimize the discrepancy due to limited availability of historical water quality data extensive efforts were placed in collecting site-specific data for model inputs such as soil properties, agricultural practice information and land use. Moreover, calibration parameter ranges suggested in the literature are utilized during calibration in order to obtain more realistic representation of Lake Mogan Watershed in the model. Model performance is evaluated using comparisons of the measured data with 95%CI for the simulated data and comparison of unit pollution load estimations with those provided in the literature for similar catchments, in addition to commonly used evaluation criteria such as Nash-Sutcliffe simulation efficiency, coefficient of determination and percent bias. These evaluations demonstrated that even though the model prediction power is not high according to the commonly used model performance criteria, the calibrated model may provide useful information in the comparison of the effects of different management practices on diffuse pollution and water quality in Lake Mogan Watershed.

Probabilistic Evaluation of the Effects of Uncertainty in Transient Seepage Parameters

AbstractThis paper investigates the effect of uncertainty in the hydraulic conductivity and van Genuchten fitting parameters used for unsaturated flow modeling of transient seepage through embankme...

A GIS Tool to Estimate Flow at Ungaged Basins Using the Map Correlation Method.

Water resources management has been a critical component of sustainable resources planning. One of the most commonly used data in water resources management is streamflow measurements. Daily streamflow time series collected at a stream gage provide information on the temporal variation in water quantity where the gage is located. However, streamflow information is often needed at ungaged catchments especially when the stream gage network is not dense. One conventional approach to estimate streamflow at an ungaged catchment is to transfer streamflow measurements from the spatially closest stream gage, commonly referred to as the donor or reference gage using the drainage-area ratio method. Recently, the correlation between daily streamflow time series is proposed as an alternative to distance for reference stream gage selection. The Map Correlation Method (MCM) enables development of a map that demonstrates the spatial distribution of correlation coefficients between daily streamflow time series at a selected stream gage and all other locations within a selected study area. Although utility of the map correlation method has been demonstrated in various studies, due to its geostatistical analysis procedure it is time-consuming and hard to implement for practical purposes such as installed capacity selection of run-of-river hydropower plants during their feasibility studies. In this study, an easy-to-use GIS-based tool, called MCM_GIS is developed to apply the MCM in estimating daily time series of streamflow. MCM_GIS provides a user-friendly working environment and flexibility in choosing between two types of interpolation models, kriging and inverse distance weighting. The main motivation of this study is to increase practical application of the MCM by integrating it to the GIS environment. MCM_GIS can also carry out the leave-one-out cross-validation scheme to monitor the overall performance of the estimation. The tool is demonstrated on a case study carried out in Western Black Sea Region, Turkey. ESRI’s ArcGIS for Desktop product along with a Python script is utilized. The outcomes of inverse distance weighting and ordinary kriging are compared. Results of GIS-based MCM are in good agreement with the observed hydrographs.

Spatial Distribution of Groundwater Availability for Various Pumping Scenarios in Savannah Region

Long-term pumping from the Upper Floridan Aquifer (UFA) in the Savannah region, Georgia has lowered groundwater piezometric heads significantly. This resulted in salt water intrusion and brackish water contamination of the aquifer at Hilton Head Island, S.C. The aquifer is a primary source of drinking and industrial process water in the region, thus, various categories of users apply for groundwater withdrawal permits. The Georgia Environmental Protection Division (EPD) wants to develop a long term groundwater management plan which will protect the UFA from further salt water intrusion and also allow additional groundwater withdrawals from the aquifer. To achieve this goal, EPD first developed an “Interim Strategy for Managing Salt Water Intrusion in the Upper Floridan Aquifer of Southeast Georgia (EPD 1997)”. In this interim strategy, EPD has identified an area for enforced protection near the City of Savannah. Thus, since 1997, EPD has not issued permits for groundwater withdrawal from the UFA in the northern-capped area unless such water is reallocated from a permit reduction elsewhere within the northern-capped area (EPD 2004). EPD also initiated a program called Coastal Sound Science Initiative (CSSI) to generate data and information for developing a plan for managing salt water intrusion (EPD 2005). EPD’s goal was to find answers for various questions related with the salt water intrusion problem in the region. Two of these questions were: (i) Can areas having minimal impact on salt water intrusion be identified and what amount of water can be obtained from them?, and (ii) What are the other fresh water sources in coastal Georgia and what amount of water can be obtained from them? In this study, we proposed a coupled simulationoptimization model to determine spatial distribution of additional groundwater availability within the Savannah region. We used this model to investigate spatial distribution of groundwater availability for various management scenarios, such as groundwater is withdrawn from the Lower Floridan Aquifer (LFA) from the UFA, or from the LFA and the UFA simultaneously (UFA+LFA). The results obtained from this analysis will be useful in answering the two questions posed by EPD and also will provide preliminary guidance in long term management and planning goals.