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    Benchmarking and assessment of irrigation management transfer effects on irrigation performance in Turkey
    (Asian Network for Scientific Information, 2007) Yildirim, Murat; Cakmak, Belgin; Gokalp, Zeki
    The objectives of this study are to identify irrigation management transfer effects on irrigation performance and to benchmark public irrigation schemes and transferred irrigation schemes. In this study, benchmarking performance indicators were applied both on state-managed and transferred irrigation schemes. Based on 1995-2002 data, following results were obtained for performance indicators of state-managed schemes: Water Delivery per Command Area (WDCA): 3547-6500 m3 ha-1 Water Delivery per Irrigated Area (WDIA): 10054-13603 m3 ha-1; Relative Water Supply (RWS): 2.33-3.49; Gross Value of Output for Command Area (GVPCA): 710-1775 $ ha-1; Gross Value of Output for Irrigated Area (GVPIA); 1937-3550 $ ha-1; Gross Value of Output for Irrigation Supply (GVPIS); 0.19-0.31 $ m-3; Gross Value of Output for Water Consumed (GVPWC); 0.55-0.78 $ m-3. For the same period following results were derived in transferred schemes: water delivery per command area: 6431-7933 m3 ha-1; water delivery per irrigated area: 9127-11320 m3 ha-1; relative water supply: 2.05-2.45; gross value of output for command area: 1166-2265 $ ha-1; gross value of output for irrigated area; 1635-3121 $ ha-1; gross value of output for irrigation supply; 0.18-0.31 $ m-3; gross value of output for water consumed; 0.41-0.70 $ m-3. Amount of water used was more than required amounts and performances were low in both schemes. However, irrigation performance was higher in the transferred schemes than state-managed ones. Since water savings were increased by developing a sense of ownership concept during the post-transfer in transferred schemes and more efficient water use was provided. © 2007 Asian Network for Scientific Information.
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    HEAVY METAL, NITROGEN AND PHOSPHORUS ADSORPTION OF COMPACTED LINER MIXTURES
    (Parlar Scientific Publications (P S P), 2018) Gokalp, Zeki; Tas, Ismail; Uzun, Oguzhan; Kaplan, Sema; Basaran, Mustafa
    Nitrate, phosphorus and heavy metals are among the most common pollutants and create potential dangers for groundwater contamination. In this research, a liner design was proposed for waste repository sites, constructed wetland basins and manure management lagoons to prevent groundwater contamination by seepages from the bottom of these facilities. For this purpose, sand-bentonite and pumice-bentonite mixtures with pre-defined grain size range (1.00-0.50 mm) and bentonite content (30%) was used. The mixtures were compacted at optimum moisture content and maximum dry weight and then permeability tests were carried out over compacted mixtures. Various concentrations of nitrate, phosphorus (25, 50, 100, 150 and 200 ppm) and heavy metal (Cd, Ni, Pb, Cr and Cu) solutions (10, 20, 30, 40 and 50 ppm) were used to saturate the permeability test samples. Extracts of permeability tests were used to investigate the adsorption characteristics of proposed mixtures for liner design. With regard to heavy metal adsorption, bentonite had the best performance because it is a clay mineral. Sand and pumice exhibited similar performances in lead and cadmium adsorption, but pumice had much better performance than sand in chrome, copper and nickel adsorption. Although sand-bentonite and pumice-bentonite mixtures exhibited similar performance in nitrate adsorption, again pumice-bentonite mixtures had much better performance than sand-bentonite mixtures in phosphorus adsorption. Current results revealed that pumice with macro-micro pore structure and resultant adsorptive surface characteristics could be used as an alternative of sand in liner design.
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    Spatial distribution and health risk assessment for heavy metals of the soils around coal-fired power plants of northwest Turkey
    (Taylor & Francis Ltd, 2024) Parlak, Mehmet; Tas, Ismail; Gorgisen, Ceren; Gokalp, Zeki
    This study was conducted to determine heavy metal concentrations of the soils around two thermal power plants located in & Ccedil;anakkale province (northwest Turkey) and health hazards of these heavy metals. By using random sampling method, 45 surface soils (0-5 cm depth) were taken from around the thermal power plants and heavy metal analyses were conducted on these samples. Average values of some heavy metals were greater than the normal background levels, and the others were lower than the background levels. While Cd, Cr, Mn, Ni and Zn concentrations were higher than worldwide soils, Co, Cu, and Pb concentrations were lower than worldwide soils. Correlation analysis revealed significant positive correlations (p < 0.05) between 1) Co and Cd, 2) Cr and Cd, 3) Ni and Cd, 4) Pb and Cu, 5) Zn and Mn 6) Zn and Pb and highly significant positive correlations (p < 0.01) between 1) Cu and Cd, 2) Mn and Cd, 3) Zn and Cd, 4) Cr and Co, 5) Cu and Co, 6) Mn and Co, 7) Ni and Co, 8) Cu and Cr, 9) Mn and Cr, 10) Ni and Cr, 11) Ni and Cr, 12) Mn and Cu, 13) Ni and Cu, 14) Zn and Cu. Health risk assessments of heavy metals were made based on both carcinogenic and non-carcinogenic risk index. The total non-carcinogenic risk index is 3.87E-01 for children and 4.67 E-02 for adults and present values were above these limits. Carcinogenic risks of heavy metals in children and adults were determined in the order of Cr > Pb > Ni > Co > Pb. Cr and Pb were found to be higher than the acceptable risk range (10-6-10-4) in children and adults. Since Cr and Pb concentrations exceed the limit values, heavy metal contents of the soils in the study area should be monitored regularly.