Evaluating the anthropogenic and geologic impacts on water quality of the Eğirdir Lake, Turkey

E?irdir Lake is the second largest fresh water lake with 482 km² surface area of Turkey. The lake is an indispensable water source for our country and region because of available water capacity and usage aims such as drinking-irrigation water, tourism, and fishing. However, especially contaminants located in the E?irdir Lake catchment affect the lake water quality negatively in times. Therefore, determination of the water quality of the lake has quite importance for region human health and sustainable usage of the lake. The major factors that control the quality of the E?irdir Lake water are agricultural activities in the basin, water–rock interaction, and domestic and industrial wastes. This study investigates the anthropogenic and geologic impact originated from pollution sources and water–rock interaction in the lake watershed basin to the E?irdir Lake water quality. For this purpose, geological, hydrogeological, and hydrological properties of the lake basin with point and nonpoint pollution sources were investigated. To determine the water quality of the lake, 48 water samples were collected especially from locations representing effects of pollutants in May and October 2009. The analysis results were compared with maximum permissible limit values recommended by World Health Organization and Turkish drinking water standards. The contents of all chemical and physical parameters are higher in dry periods than wet period, and water pollution was observed at discharge points of the streams into the lake. Also, pH, turbidity, potassium, chemical oxygen demand, ammonium, aluminum, iron, and lead concentrations were found to be above drinking water standards.     

Using vorticity to quantify the relative importance of heterogeneity, viscosity ratio, gravity and diffusion on oil recovery

The vorticity of the displacement velocity is used to derive dimensionless numbers that can be used to quantify the relative importance of viscosity ratio, gravity, diffusion/dispersion and permeability heterogeneity on secondary hydrocarbon recovery. Using this approach, a new objective measure of the impact of permeability and porosity heterogeneity on reservoir performance is obtained. This is used, in conjunction with other dimensionless numbers, to analyse the relative impact of heterogeneity, buoyancy effects, mobility ratio and dispersion on breakthrough time and recovery at 1 pore volume injected during first contact miscible gas injection. This is achieved using results obtained from detailed simulation of miscible displacements through a range of geologically realistic reservoir models. This study goes some way towards developing a unified mathematical framework to determine under which flow conditions reservoir heterogeneity becomes more important than other physical processes. We propose that comparison of these dimensionless numbers can be used to identify the key factors controlling recovery and thus assist the engineer in determining appropriate enhanced oil recovery techniques to improve recovery.     

Assessment of trace metal contents in water and bottom sediments from Eğirdir Lake,Turkey

The concentration of metals (Pb, As, Co, Cu, Ni, Zn, Fe and Mn) was investigated in water and sediment samples of E?irdir Lake. The Lake is the second largest fresh water lake of Turkey and it is used as drinking water in the region. The anthropogenic pollutants are primary sources of trace metals which are negatively affected lake water quality. These negative effects were observed in both lake water and bottom sediments. According to obtained data, Pb, Cu, Ni, Fe and Zn have significant enrichment in sediments samples. In addition, the hydrodynamic model of the lake was determined as effectively for Pb, Co, Cu, Ni, Zn, Fe and Mn accumulations. Also, the effect of anthropogenic pollutants was found to be more dominant than geogenic effect in metal accumulation of the lake bottom sediments. Therefore, anthropogenic pollutants within the lake basin should be consistently controlled for the sustainable usage of the lake.     

Rock quality designation-fracture intensity index method for geomechanical classification

Rock quality designation (RQD) is a simple and effective way of rock mass classification from surface scanlines or preferably borehole measurements. A major drawback in its classical use is that only one representative RQD value is obtained from the field measurements per core run. However, it is shown in this paper that the field measurements along a scanline provide detailed information about the rock quality and the fracture intensity (FI) for a given number of joints. In order to be able to extract the complete information concealed within the field data, the RQD-fracture index diagram concept is proposed and applied to actual field scanline measurements from England. The basis of the suggested procedure is to obtain a series of all possible RQD and FI values from given intact length measurements. This procedure provides additional information as to the local zones of heterogeneities within the rock mass and a new way of rock classification on the basis of the combined effects of RQD and FI. It is also possible to calculate percentages of different rock qualities within the same rock mass.     

Petrochemistry and petrology of I-type granitoids in an arc setting: the composite Torul pluton, Eastern Pontides, NE Turkey

The Upper Cretaceous Torul pluton, located in the Eastern Pontides, is of sub-alkaline affinity and displays features typical of volcanic arc granitoids. It is a composite pluton consisting of granodiorite, biotite hornblende monzogranite, quartz monzodiorite, quartz monzonite and hornblende biotite monzogranite. The oldest syenogranite (77.9 ± 0.3 Ma) and the youngest quartz diorite form small stocks within the pluton. Samples from the granodiorites, biotite hornblende monzogranites, quartz monzodiorites, quartz monzonites and hornblende biotite monzogranites have SiO₂ between 57 and 68 wt% and display high-K calc-alkaline, metaluminous to peraluminous characteristics. Chondrite-normalized REE patterns are fractionated (La_cn/Lu_cn = 6.0?14.2) with pronounced negative Eu anomalies (Eu/Eu* = 0.59–0.84). Initial ?_Nd(i) values vary between ?3.1 and ?4.1, initial ⁸⁷Sr/⁸⁶Sr values between 0.7058 and 0.7072, and δ¹⁸O values between +4.4 and +7.3‰. The quartz diorites are characterized by relatively high Mg-number of 36–38, low contents of Na₂O (2.3–2.5 wt%) and SiO₂ (52–55 wt%) and medium-K calc-alkaline, metaluminous composition. Chondrite-normalized REE patterns are relatively flat [(La/Yb)_cn =  2.8–3.3; (Tb/Yb)_cn =  1.2] and show small negative Eu anomalies (Eu/Eu* = 0.74–0.76). Compared to the other rock types, radiogenic isotope signatures of the quartz diorites show higher ⁸⁷Sr/⁸⁶Sr (0.7075–0.7079) and lower ?_Nd(i) (–4.5 to –5.3). The syenogranites have high SiO₂ (70–74 wt%) and display high-K calc-alkaline, peraluminous characteristics. Their REE patterns are characterized by higher La_cn/Lu_cn (12.9) and Eu/Eu* (0.76–0.77) values compared to the quartz diorites. Isotopic signatures of these rocks [?_Nd(i) =  ?4.0 to ?3.3; ⁸⁷Sr/⁸⁶Sr_(i) =  0.7034?0.7060; δ¹⁸ O =  + 4.9 to + 8.2] are largely similar to the other rock types but differ from that of the quartz diorites. Fractionation of plagioclase, hornblende, pyroxene and Fe–Ti oxides played an important role in the evolution of Torul granitoids. The crystallization temperatures of the melts ranged from 800 to 900°C as determined from zircon and apatite saturation thermometry. All these characteristics, combined with low K₂O/Na₂O, low Al₂O₃/(FeO_T + MgO + TiO₂), and low (Na₂O + K₂O)/(FeO_T + MgO + TiO₂) ratios suggest an origin through dehydration melting of mafic lower crustal source rocks.     

Spatiotemporal dry and wet spell duration distributions in southwestern Saudi Arabia

Summary Regional dry and wet spell durations within a 15 year period are mapped for the southwestern part of Saudi Arabia for summer and winter. If the number of spells is plotted versus duration a straight-line results on semi-logarithmic paper for most stations. However, a few stations exhibit two or three different slopes showing the effect of local climate. Simple regression equations are proposed for the dry or wet spell duration at any station allowing the mapping of regional variation for the entire study area. Such maps are useful tools in the assessment of the spatial and/or temporal wet and dry period duration for the area between stations. Similar maps could be developed for other parts of the world.With 10 Figures     

Flash flood inundation map preparation for wadis in arid regions

Flood inundation maps are dependent on the topographic and geomorphologic features of a wadi (drainage basin) in arid regions, which are most susceptible for potential flash flood occurrences, such as in the southwestern part of the Kingdom of Saudi Arabia. It is not possible to control the potential flood hazards by using only technological instruments that forewarn the occurrences or imminence. Additionally, it would be better to prepare flood risk maps so as to delineate the risky areas to educate the administrators and local settlers. The availability of these maps is the key requirement for any urban development that entails land use allocation, identification of dam, tunnel, highway, bridge sites, and infrastructure locations for sustainable future. This paper suggests the necessary steps in flood inundation map preparation after determining the possible flood discharge. For this purpose, a set of critical cross-sections along the possible flood plain are taken in the field with surveying methods and measurements. The calculation of the average flow velocity in each section is calculated according to the cross-section geometric, hydraulic, and material properties. Synthetic rating curves (SRC) are prepared for each cross section, which are very useful especially in arid and semi-arid regions where there are no perennial surface water flows for natural rating curve measurements. All the SRCs appear in the form of power function which relates the flow depth to discharge in a given cross section. It is then possible to calculate the flood depth in the cross section through its SRC. Depending on the cross-section shape, the flood width can be calculated. The connection of a series of widths on a scaled topographic map delineates the flood inundation area. If digital elevation map (DEM) is available, then the SRCs can be integrated with these maps and the flood inundation delineation can be achieved automatically. Since DEMs are not available, the topographic maps are used for this purpose in order to delineate flood inundation areas within wadis Hali and Yiba from the southwestern Kingdom of Saudi Arabia.     

Community structure of epiphytic algae on three different macrophytes at Acarlar floodplain forest （northern Turkey）

The aim of this study was to determine the species composition, biodiversity and, relative abundance of epiphytic algae and their relationship with environmental variables on three different macrophytes( Nymphaea alba, Ceratophyllum demersum, Typha latifolia) at Acarlar Floodplain Forest(AFF). Epiphytic algae were gathered monthly by collecting aquatic plants between November 2011 and October 2012, except in winter when there were no plants. In this study, 67 taxa on N. alba, 66 taxa on C. demersum and 66 taxa on T. latifolia were identified as epiphytic algae. The mean value of species richness was 17, that of diversity was 1.5 and that of evenness was 0.54 for epiphytic algae on N. alba, 17, 1.1, and 0.39 on C. demersum, and 18, 1.64, and 0.56 on T. latifolia, respectively. Oscillatoria sp. and Komvophoron crassum(Vozzen) Anagnostidis and Komárek were the most abundant and consistent epiphytic algal species, occurring in high abundance on all macrophytes. Results show that species composition of epiphytic algae was different, but diversity values were similar on all the macrophytes. The hydrological pulse is one of the most important factors determining the physical and chemical environment of the epiphytic algal community. However, substrate type also affected the colonization by F. capucina, O. sancta, P. catenata, and L. truncicola more than the epiphytic algal seasonality.