Melen River Research Articles

Assessing microplastic pollution in a river basin: A multidisciplinary study on circularity, sustainability, and socio-economic impacts

Plastic pollution has emerged as a significant environmental challenge worldwide, posing serious threats to ecosystems and human health. This study seeks to explore the interplay among circularity, sustainability, and the release of microplastics within the freshwater ecosystems situated along the western Black Sea coast- Düzce, Türkiye. Employing a multidisciplinary approach that integrates environmental science, economics, and policy analysis, the research examines the current state of plastic pollution in the region, considering diverse land uses and socio-economic lifestyles. Conducted over four different seasons, the current study identifies the prevailing types of microplastics in the region. Fibers dominate, comprising 86.7% in each season, followed by film and fragments at 7.7% and 7.0%, respectively. Notably, polyethylene (PE) and polypropylene (PP) emerges as the primary polymer types. The distribution of polymer types varies across different land uses within the region, emphasizing the influential role of land use in shaping the abundance polymer composition. The comprehensive assessment of pollution, as reflected in the overall pollution load index (PLI) of the Melen River indicating a concerning level of pollution (PLI>1). Finally, the study unveiled the relationship between socio-economic activities as well as the seasonal precipitation patterns, and microplastic contamination in the region. This underscored the importance of site-specific mitigation measures on reducing the amount of microplastics. Lastly, incorporating sustainable practices within the circular economy framework fosters a harmonious balance between economic development and environmental protection in Türkiye.

Performance of Chitosan/Carbon Nanotube-Coated Ultrafiltration Membranes for Natural Organic Matter Removal from Drinking Water

The objective of this study is to improve the filtration efficiency of commercially available polyethersulfone (PES) ultrafiltration (UF) membranes, with a specific focus on removing natural organic matter (NOM) and preventing membrane fouling. The modification of UF membranes was accomplished by utilizing chitosan/multi-walled carbon nanotubes (CS/MWCNT-OH) and employing both dip and spin coating techniques. The membrane surface morphologies were evaluated using the Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM), and Energy-Dispersive X-ray Spectroscopy (EDX) techniques. Tests were carried out to assess the effectiveness of the membranes in a laboratory-scale system using two primary water sources from Istanbul, specifically the Melen River and Terkos Lake. Total organic carbon (TOC), UV254 absorbance, turbidity, and trihalomethane formation potential (THMFP) were all measured as part of a thorough analysis. The surface morphology investigations verified the effective deposition of MWCNT-OH nanoparticles onto the membrane surface. This was corroborated by the reduction in the water contact angle, showing an improvement in the hydrophilicity of the membrane. The modified membranes demonstrated much higher TOC removal rates compared to the original membranes. Specifically, the removal efficiencies for Melen River and Terkos Lake were 37.14% and 56.86%, respectively. Nevertheless, the alteration of the surface led to a decline in membrane flux as a result of the concurrent drop in pore size. To summarize, the results of this work highlights the considerable capability of surface modification using CS/MWCNT-OH to improve the performance and antifouling characteristics of commercial PES UF membranes.

Riparian Soil Pollution Caused by Sediment Metal Transport: Seasonal Changes and Ecological Risk Assessment.

The accumulation of pollutants in the sediment along surface water may negatively affect riparian zones and increase ecological risk. This article investigates the effects of metal sediments on riparian soil via field monitoring and ICP-OES analysis. To this end, pollution levels, seasonal changes, and potential sources of the pollutants were determined for the Melen River watershed, Turkey. The ecological statuses (contamination factor, enrichment factor, index of geo-accumulation, pollution index, modified pollution index, and potential and modified ecological risk indexes) of the watershed were also analyzed. Although no significant seasonal differences in the metal sediments were observed, their spatial distribution in the sediments and riparian soils varied markedly. Cr (11.4 to 136), Co (7.7 to 21.52), Cu (11.4 to 76.6), and Ni (14.06 to 128.2) recorded as mg/kg significantly increased from the upstream to the downstream. The metals possessing the highest risk in the sediment and riparian soil regarding the river health were Cu, Co, and Ni. The risk values were found to be heavily polluted (PI > 3 and MPI > 10), and the risk indexes were above the "desired environment without the risk". The risk index was found to be more than 50, and the modified risk indexes exceeded 200 at many points. The transportation of pollutants in surface water became evident in the sediment, resulting in adverse effects on the riparian zone and the ecological system.

Düzce Melen Havzası (Türkiye) Barbus tauricus (Kessler, 1877) Populasyonu’nun Yağ ve Yağ asidi Profilinin Mevsimsel Değişimi

In this study, total lipid and fatty acid profiles of Barbus tauricus samples which were obtained from Melen River Basin during winter, spring, and summer seasons, were evaluated. Total lipid levels were determined 2.27%, 2.37%, and 4.34% in winter, spring, and summer, respectively. The study also determined that the carbon count of 30 fatty acids, composing total fat compositions of B. tauricus caught in Melen Basin, ranges among 12-24. The major fatty acids of B. tauricus are palmitic acid and stearic acid from SFA; palmitoleic acid, trans oleic acid, oleic acid and erucic acid from MUFA and linoleic acid, alfa linolenic acid, eicosapentaenoic acid and docosahexaenoic acid from PUFA. The study is the first one on lipid and fat profiles of B. tauricus, one of the species living in Duzce Melen Basin and having high economic importance, and aimed to investigate total lipid and fatty acid profiles according to the season.

A practical approach to revise the Oxynoemacheilus bergianus species group (Teleostei: Nemacheilidae).

The Oxynoemacheilus bergianus species group is revised based on tree topology (ML, NJ, MP), distance (K2P and ASAP) and Poisson tree process analyses of DNA barcode data tested against morphometric and morphological characters including colour patterns. The O. bergianus species group is distinguished from other Oxynoemacheilus groups based on morphological characters: its constituent species have a slender caudal peduncle, a suborbital flap in the male, a mottled or blotched colour pattern, and lack bold, black spots on the caudal-fin base. It is also supported as a monophyletic unit in our molecular analysis. The O. bergianus group includes 10 molecular clades following congruently well-supported NJ, MP and ML based entities. Species described as O. bergianus, O. banarescui, O. erdali, O. fatsaensis, O. samanticus, and O. simavicus from Turkey, O. lenkoranensis from Azerbaijan, and O. longipinnis and O. parvinae from Iran belong to this species group. The group includes also four unnamed molecular clades. We were unable to detect external differences between any of the molecular clades in colour pattern or any morphometric or morphological characters examined. In the 10 molecular clades in the O. bergianus species group, the intraclade K2P distance ranges from 0.01.8% while the distances between molecular clades ranges from 0.65.9%. To resolve the species diversity of this group, we also analysed the intraspecific and interspecific variability in the K2P distance of DNA barcode data from 53 other Oxynoemacheilus species. Here, the intraspecific variability ranges from 0.02.4% while the interspecific K2P distance ranges from 1.220.8%. In the O. bergianus species group, only four groups are detected by the mPTP species delimitation approach distinguished by a K2P distance of 2.9% or more. We treat these four groups as valid species, corresponding to O. banarescui, O. bergianus, O. fatsaensis, and O. simavicus. Oxynoemacheilus samanticus from the Kzlrmak and Seyhan drainages, O. lenkoranensis from the Caspian basin, O. erdali from the Euphrates, and O. longipinnis and O. parvinae from the Tigris drainage are treated as synonyms of O. bergianus. Fishes from an unnamed molecular clade from the upper Tigris, and from a second unnamed clade from the upper Euphrates, are both identified as O. bergianus. Oxynoemacheilus bergianus might be a junior synonym of O. bergi from the Kura. The distribution range of O. simavicus, described from the Simav drainage in the Marmara basin, is expanded to the east and two molecularly differentiated population groups occur in the Sakarya drainage, the Byk Melen River and potentially in other adjacent coastal streams. Oxynoemacheilus fatsaensis, described from the coastal stream Eleki in northern Anatolia, is also widespread in the Yeilrmak drainage. Morphological characters proposed to distinguish O. fatsaensis from the other species of the O. bergianus group could not be confirmed by our data on fishes from the Yeilrmak. This study also discusses the theoretical background, our reasons for conducting this revision in the way we did, and what the alternatives would be.

Age and Growth of the Bulgarian Minnow, Phoxinus strandjae (Drensky, 1926) (Actinopterygii: Cypriniformes: Cyprinidae) Living in Melen River Basin (Düzce, Turkey)

This study aims to present the growth parameters of Endangered (EN) (IUCN Redlist). Phoxinus strandjae which until very recently has been believed to be existing only in a very limited area around Turkey’s Thrace region and in Bulgaria (in Europa continent). At the same time, this study is the first to be conducted on an Asian continent population. The study was performed on 159 individuals of P. strandjae species obtained during fauna follow-up project conducted in October, 2015 in Kucuk Melen creek in Melen River basin. The examined samples include 55 (34.59%) female and 104 (65.41%) male specimens. Female to male ratio was found as 1:1.89 among 159 specimens. As a result of examining otolith and scale readings of individuals, the age distributions were determined between 0 to 3 for females and 0 to 4 for males. The lengths of females examined within the study was determined as 78.16 mm max., while of the males was determined 90.00 mm in male; the maximum weights for females and males were 5.54 g and 7.78 g, respectively. The length-weight relationship for female and male individuals of P. strandjae were W=0.00786×L3.1689 and W=0.0083×L3.1339, respectively. The longitudinal growing parameters calculated according to von Bertalanffy formulation for female and male individuals, and asymptote value for female individuals (L∞) was calculated as 17.509 cm, Brody’s growth coefficient (K) as 0.1191 year-1, hypotheticage of fish before hatching (t0) as –1.61512; while the same values for male were calculated as L∞=18.356 cm, K=0.1102 year-1, t0= –1.63994 year and for all populations as L∞=17.642 cm, K=0.1179 year–1, t0=–1.5942 year. This is the first study performed about age and growth parameters of P. strandjae on Anatolia population. At the end of the study, it was found that Bulgarian minnow (P. strandjae) in Melen River basin demonstrating positive allometric growth.

17-18 Temmuz 2019 Akçakoca ve Cumayeri (Düzce) Sel Afeti Sonuçları ve Müdahale Çalışmaları

Dünyada doğal afetler etkisini artırarak görülmeye devam etmektedir. İnsan nüfusunun artması ile birlikte plansız yapılaşma, ormanların tahrip edilmesi vb nedenler ile birlikte afetlerin etkileri de artmaktadır. Afetler beraberinde çevre sorunlarının yanı sıra can ve ekonomik kayıplara neden olmaktadır. Doğal afetlerden sel felaketi son zamanlarda sıklıkla dünyanın farklı bölgelerinde yaşandığı gibi ülkemizde de özellikle Karadeniz Bölgesinde sıklıkla yaşanmaktadır. Ani yağışlar, derelerin taşması gibi farklı nedenlere bağlı olarak seller meydana gelmektedir. Batı Karadeniz Bölgesinde bulunan Düzce genelinde 17 Temmuz 2019 günü başlayan yoğun yağmur yağışı 18 Temmuz 2019 günü de devam ederek sele neden olmuş, Düzce’nin Akçakoca ve Cumayeri ilçelerini zarar verecek boyutta etkilemiştir. Selden kaynaklı can kayıpları ve ekonomik kayıplar yaşanmıştır. Özellikle Akçakoca ilçesi selden en çok etkilenen yerlerden biri olmuştur. Akçakoca merkez ve köylerin hemen içerisinden geçen Melen nehri üzerinde meydana gelen taşkınlar sonrası kayıplar daha da artmıştır. Bu taşkınların oluşmasında yoğun yağmur sularının ormanlık alanlardan getirdiği ağaç, toprak, taş vb nehrin debisini düşürerek taşkınlara neden olmuştur. Çalışmada Düzce İli Akçakoca ve Cumayeri ilçelerinde sel felaketinin neden olduğu kayıplar ve Düzce İl AFAD Müdürlüğü’nün TAMP (Türkiye Afet Müdahale Planı) kapsamında müdahale çalışmaları tüm boyutları ile ele alınmıştır. Düzce İl AFAD müdürü ve görev yapan teknik personeller ile görüşmeler yapılarak ve sel ile ilgili raporlar incelenerek sel felaketinde yapılan müdahale çalışmaları hakkında detaylı bilgiler edinilmiştir. Çalışmada sel felaketi kapsamında yapılan müdahalelerin zamanında, yeterli ekip ve ekipmanlar ile yapıldığı, tahliyelerin ve barınma sorunlarının çabuk bir şekilde çözüldüğü tespit edilmiştir.

Studija slučaja uređenja i korišćenja zemljišta za određivanje načina upravljanja zemljištem koji se može primeniti u poljoprivrednoj praksi za sprečavanje erozije i gubitka plodnog zemljišta

The Büyük Melen river in the Melen Basin meets Istanbul's drinking water needs. Protecting the basin against nutrient pollution is vital in this regard as well. This study focuses on the best possible management practice (BMPs) in the Melen Basin to reduce the export of nutrients from the agricultural areas. A region comprising industrial, farming, and residential zones is the Melen basin. There is a forecast of global climate change in Turkey, and scientists and also governors must know which areas are no longer farming zones and which will be more appropriate for agriculture. Turkey's territory is a high-risk desertification area. In Melen Basin, the soil type and land use properties have been determined and mapped using GIS and Soil and Water Assessment Tool (SWAT). Buffer BMP filter strips can be used effectively for nutrient protection that can be carried from residential areas and motorways by runoff. The region in the basin is steep, and its clay and sandy soil structures are ideal for parallel terraces, grade stabilization, strip, and contour cultivation. Unless the ground can not retain or store water, the soil can undergo sudden floods, causing an erosion of the soil's productive surface layer. When we protect the land, this condition is reduced. The land type and land use mapping should be drawn up as soon as possible for the remaining Turkish basins by scientific methods. This research is intended to be an illustration for researches on other agricultural basins in Turkey and the world for this reason.

Seasonal changes in fat and fatty acid profiles of the Sakarya Chub (Squalius pursakensis) from the Melen river basin

Total lipids, fatty acid composition of Squalius pursakensis fillet samples captured from Melen River Basin during winter, spring and summer seasons were evaluated. Total lipid levels were as 1.80% in winter, 2.56% in spring and 5.17% in summer. The composition of fatty acids showed that total polyunsaturated fatty acids (32.05-38.90%) were highest, followed by monounsaturated (29.85-35.40%) and saturated (27.10-31.23%). The fatty acid composition of polyunsaturated fatty acids (PUFAs) in fillets of S. pursakensis shows a high content n3 fatty acids eicosapentaenoic acid (EPA C20:5n3) and docosahexaenoic acid (DHA C22:6n3) with maximum rates of 6.70% and 16.33%, respectively (p<0.05). The saturated fatty acid (SFA) content was dominated by palmitic acid with the maximum ratio of 19.03%.

Melen Havzasında Besin Maddeleri için Nehir Alıkonum Katsayısının Tespiti

Melen Watershed is the most recent and the leading drinking water source of Istanbul. According to The Ministry of Forest and Water Works of Turkey, regarding the pollution status, Melen River Basin should be primarily dealt with. Nutrient pollution such as nitrogen (N) and phosphorus (P) can cause water quality degradation in rivers, which are used as a source of drinking water. Buyuk Melen and Kucuk Melen rivers are existed on Melen Watershed. Water supplied from Buyuk Melen River is tranferred to Omerli Dam and supplies important percent of the water demand of the Istanbul. Hence, it is crucial to observe the water quality of the supplied water in Melen Watershed. Certain percent of the nutrients that cause the organic pollution are retained through the river route. River retention coefficient is the percent that reflects how many percent of the nutrients are retained during the river flow. River retention coefficient for the rivers on the Melen Watershed was calculated according to the several factors mentioned in this study. For this purpose geographical information systems (GIS) were also dealt with and digital elevation model (DEM) was prepared using raster images scaled 1/25000. This study is aimed to be an important precedent for other basins that are determined as in priority in terms of pollution by The Ministry of Forest and Water Works of Turkey.

Trace metal surface water inflow and retention in different terms of the wetland

Wetlands are important ecosystems that provide biodiversity and buffer aquatic ecosystems. This study monitored the quality of surface water in the Efteni wetland system in Turkey, which is intertwined with the Melen River. Basic water quality parameters and 26 different trace elements were analysed by standard methods (USEPA method 200.7 and ISO 11885) using inductively coupled plasma in water samples taken from inflows, an internal lake and the outlet of the wetland in different seasons (before, during and after the flowering) in 2011. Trace element concentrations differed between tributaries flowing to and within the wetland. Natural attenuation was observed for health risk elements such as molybdenum, copper, nickel, boron and vanadium in all seasons. Most trace elements were observed at their lowest levels during the flowering period. These results confirm that the Efteni wetland acts as a retention zone and, due to its important location in the River Melen watershed, warrants protection.

Water Quality Assessment Using Artificial Intelligence Techniques: SOM and ANN—A Case Study of Melen River Turkey

Artificial intelligence methods have been employed with regard to 26 sets of physical and chemical pollution data obtained from the Melen River by the Turkish State Hydraulic Works during the period of 1995–2006. Water-quality data are divided into two parts relating to the high- and low-flow periods for the 1 KMP, 2 BMP, and 3 BMA stations. The self organizing map–artificial neural networks (SOM–ANNs) is employed to evaluate the high–low flow period correlations in terms of water-quality parameters. This is done in order to extract the most important parameters in assessing high–low flow period variations in terms of river water quality. The map size chosen is 9 × 9 in order to ensure that the maximum number of groups would be obtained from the training data. The groups explaining the pollution sources are identified as being responsible for the data structure at each dataset. The SOM, supported by ANN, is applied to provide a nonlinear relationship between input variables and output variables in order to determine the most significant parameters in each group. The multilayer feed-forward NN is chosen for this study. The most crucial parameters are determined, and the groups are conditionally named as mineral structure; soil structure and erosion; domestic, municipal, and industrial effluents; agricultural activity waste-disposal sites; and seasonal effects factors. Based on the explanation of the parameters, we can have an opinion about other parameters which can lead to cost and time savings. The aim of this study is to illustrate the usefulness of artificial intelligence for the evaluation of complex data in river- and water-quality assessment identification, and pollution sources, for effective water-quality management.

The examination of the performances of methods used in separating the total stream flow in different rivers

In this study, the performances of methods of flow separation into the surface flow and base flow of the total stream flow in rivers with different hydraulic features have been examined. For this purpose, daily mean stream flow data of Büyük Melen and Aksu Rivers which are in the same watershed but with different features (average flow value, catchment area, mean elevation) have been separated as surface flow and base flow with the use of Digital Filtering Method (DFM) and United Kingdom Institute of Hydrology Method (UKIH). The recession coefficient in DFM has been used as α = 0.830; and the number of elements for the groups formed to determine the turning points of flow data in UKIH has been used as N = 5. The study has revealed that the results of surface and base flows obtained by both flow separation methods show similarity in all rivers in an acceptable level; and the surface flow values agree better (R2 > 0,76) compared to base flow values (R2 > 0.63). However, it has been seen that as long as the total flow values decrease, the surface flow results for both methods come closer to each other; but the results of base flow get differentiated. This situation has been clearly seen in the results of surface (R2 > 0.89) and base (R2 > 0.63) flows belonging to Aksu River which has lower values of flow when compared to the ones of Büyük Melen River.

Modeling and forecasting river flow rate from the Melen Watershed, Turkey

Summary The Melen Watershed is located in Western Black Sea region of Turkey. Buyuk Melen and Kucuk Melen Rivers are located in this watershed. By 2010 more than 50% of Istanbul’s water demand is supplied from the Buyuk Melen River. This paper presents a new approach using an artificial neural network (ANN) technique to improve precipitation forecast performance. Missing value predictions and the future precipitation value estimations were researched throughout this study. A case study was performed in Bolu and Duzce provinces of Turkey that are located in Black Sea Region. The most crucial objective of this study was to estimate missing values and to generate quantitative forecasts for future precipitation data of Duzce. Monthly average daily precipitation data of Bolu and limited number of Duzce precipitation data were used for this purpose. Ultimately, monthly river flow rate from the Melen Watershed of Turkey was modeled and forecasted through the SWAT Model using the generated precipitation data and other required spatial and temporal data. Results show that there is a considerable relation between the simulated model and observed results. This study also shows that water supply for Istanbul can be managed based on precipitation forecast.

Examining the sensibilities of the different sectors active in Düzce concerning clean production

Industry, having become the backbone of development and economic improvement today, increases the pressure on the natural resources, but it has carried the environmental problems to unresolvable levels. Some developed countries realising the seriousness of the issue developed various methods, techniques and technologies to reduce the environmental effects of the industry. “Clean production”, which was put forward especially with the concept of sustainable progress, was defined as inclusion of environmental sensibility to all processes from designing to planning, is an approach to reduce the industry’s environmental pressure and, in contrast to the traditional approaches, it aims to prevent pollution before it appears. In this study, the aim is to examine the practices of clean production in the fast growing industry in Duzce province, which has the most important active fault line, Melen river basin supplying clean water for Istanbul, vast forests having rich biodiversity, etc. For this purpose, in 50 enterprises directing the economy of Duzce and being active in different sectors, “a questionnaire of 43 questions including 6 parts and 37 variables” was applied with face-to-face interview method to define clean production awareness, technique and technologies. In the study, it was seen that the enterprise did not have the necessary information, technique and technology about clean production, and this situation was interpreted as the result of the industrial policies and practices in the country. Key words: Clean production, pollution control, industry, environmental sensibility, Duzce, Turkey.

Groundwater contamination and its effect on health in Turkey

The sources of groundwater pollution in Turkey are identified, and pathways of contaminants to groundwater are first described. Then, the effects of groundwater quality on health in Turkey are evaluated. In general, sources of groundwater contamination fall into two main categories: natural and anthropogenic sources. Important sources of natural groundwater pollution in Turkey include geological formations, seawater intrusion, and geothermal fluid(s). The major sources of anthropogenic groundwater contamination are agricultural activities, mining waste, industrial waste, on-site septic tank systems, and pollution from imperfect well constructions. The analysis results revealed that natural contamination due to salt and gypsum are mostly found in Central and Mediterranean regions and arsenic in Aegean region. Geothermal fluids which contain fluoride poses a danger for skeleton, dental, and bone problems, especially in the areas of Denizli, Isparta, and Aydın. Discharges from surface water bodies contaminate groundwater by infiltration. Evidence of such contamination is found in Upper Kızılırmak basin, Gediz basin, and Büyük Melen river basin and some drinking water reservoirs in İstanbul. Additionally, seawater intrusion causes groundwater quality problems in coastal regions, especially in the Aegean coast. Industrial wastes are also polluting surface and groundwater in industrialized regions of Turkey. Deterioration of water quality as a result of fertilizers and pesticides is another major problem especially in the regions of Mediterranean, Aegean, Central Anatolia, and Marmara. Abandoned mercury mines in the western regions of Turkey, especially in Çanakkale, İzmir, Muğla, Kütahya, and Balıkesir, cause serious groundwater quality problems.

Seasonal variations in phytoplankton composition and biomass in a small lowland river-lake system (Melen River, Turkey)

A series of studies were carried out to determine the succession and phytoplankton community of the Melen River in the Western Black Sea region of Turkey. The study was conducted at 6 stations at monthly intervals between May 2003 and April 2004. It was observed that the abundance and biovolume of phytoplankton were low in winter, though higher values were recorded in late spring and summer. Among the values noted, the spring peak was 534.38 × 10^5 ind. L^{-1} and 7384.8 mm^3 L^{-1} belonging to Peridinium sp. The most common diatom, Cyclostephanos dubius, was favoured by low discharge at stations 1 and 2 in the early summer (214.29 × 10^5 ind. L^{-1} and 9.84 × 10^5 ind. L^{-1}), respectively. Chlorophyll-a concentrations were between 0.86 and 64.2 \mug L^{-1}. A total of 135 taxa belonging to Cyanophyta, Bacillariophyta, Chlorophyta, Dinophyta, Euglenophyta, Heterokontophyta, Streptophyta, and Xanthophyta were identified. The total biomass of the stations 1 and 2 was mainly characterised by Dinophyta and at other stations by Bacillariophyta. Five major genera (Peridinium, Ceratium, Phacus, Cyclostephanos, and Melosira) accounted for over 70% of the total phytoplankton abundance. Phytoplankton abundance was significant and positively correlated with Chl-a and temperature (r = 0.57 and r = 0.78, respectively P < 0.05). Species richness and diversity indices increased gradually throughout the course of the river.

Ranking water quality variables using feature selection algorithms to improve generalization capability of artificial neural networks

Artificial neural networks (ANNs) have been recently used intensively in the water resource management and planning. As the demand on the clean water increases, the estimation of important parameters using ANNs to evaluate the surface water quality has become an importance practice. In this study, feature selection methods, which are important tools in data mining, are used to shed light into a further understanding in the correlation between measured parameters of water quality variables and dissolved oxygen level. The aim is to enhance the generalization ability of ANNs in prediction of dissolved oxygen level. Three different feature selection methods are utilized to discern the inherent correlation in the water quality variables in a given data set collected from Melen River, Turkey. Results show that, a small set of variable can be identified, which effectively improves the generalization ability of ANNs. Key words: Water quality, artificial neural networks, Melen river, ranking.

Water quality assessment and meta model development in Melen watershed – Turkey

Istanbul, being one of the highly populated metropolitan areas of the world, has been facing water scarcity since the past decade. Water transfer from Melen Watershed was considered as the most feasible option to supply water to Istanbul due to its high water potential and relatively less degraded water quality. This study consists of two parts. In the first part, water quality data covering 26 parameters from 5 monitoring stations were analyzed and assessed due to the requirements of the “Quality Required of Surface Water Intended for the Abstraction of Drinking Water” regulation. In the second part, a one-dimensional stream water quality model with simple water quality kinetics was developed. It formed a basic design for more advanced water quality models for the watershed. The reason for assessing the water quality data and developing a model was to provide information for decision making on preliminary actions to prevent any further deterioration of existing water quality. According to the water quality assessment at the water abstraction point, Melen River has relatively poor water quality with regard to NH 4 +, BOD 5, faecal streptococcus, manganese and phenol parameters, and is unsuitable for drinking water abstraction in terms of COD, PO 4 3−, total coliform, total suspended solids, mercury and total chromium parameters. The results derived from the model were found to be consistent with the water quality assessment. It also showed that relatively high inorganic nitrogen and phosphorus concentrations along the streams are related to diffuse nutrient loads that should be managed together with municipal and industrial wastewaters.

Hydrogeochemistry and Water Quality Evaluation along the Flow Path in the Unconfined Aquifer of the Düzce Plain, North‐western Turkey

Abstract:The Düzce Plain has a multi‐aquifer system, which consists of a near surface unconfined aquifer, along with first and second deeper confined aquifers. Hydrochemical evolution and water quality are related to infiltration of the precipitation, recharge from the formations surrounding the plain, flow path of groundwater and the relationship between surface and groundwater. The groundwater in the unconfined aquifer flows towards the Efteni Lake and the Büyük Melen River. Surface waters are divided into two main hydrochemical facies in the study area: (a) Ca2+–HCO3−; and (b) Ca2+, Mg2+–HCO3, SO2−4. The groundwater has generally three main hydrochemical facies: (a) Ca2+–HCO−; (b) Ca2+, Mg2+–HCO−3; and (c) Ca2+, Mg2+–HCO−3, CI−. The hydrochemical facies “a” and “b” dominate within shallow depths in recharge areas under rapid flow conditions, while hydrochemical facies “c” characterizes shallow and mixed groundwater, which dominate intermediate or discharge areas (near Efteni Lake and Büyük Melen River) during low flow conditions and agricultural contamination. Calcium and bicarbonate ions, total hardness and electrical conductivity of total dissolved solids (EC‐TDS) values increase along the groundwater flow path; but these parameters remain within the limits specified by the standards set for industrial and agricultural usages.