Scholarly record

WATER RESOURCE AND ENVIRONMENTAL PROTECTION IN LAKE BATLLAVA

Sabri Avdullahi

Abstract

In this paper, the case of study is water resource protection from negative influences such as climate variability and human activitie s should be approached with great care. In this survey will be trea ted water resources and envi ronmental protection is the catchments area of Lake Batllava. The catchments area of Lake Batllava has a size of 225 km² and the active storage volume of the lake is assessed to 34.4 Mill. m³. The current population of Municipality of Pris htina is estimated to be around 400,000 and Lake Batllava supply with drinking water around 64% of population in this area. The study discusses for the quality, reliability and su stainability of water supply in Prishtina as well as protection of water resources , hence improvement of living conditions, raising public health standards and promotion of economic growth in the area. The knowledge of flows reaching the Lake Ba tllava is important for developing a water resources plan. Since no usef ul hydrological data was available for the study it was decided to obtain this information by means of hydrological modelling based on a rainfall-runoff computation. The hydrologi c modelling system used, is HEC-HMS developed by the Hydrologic E ngineering Centre of the US Corps of Engineers. The model is designed to simulate the rainfall-runoff processes of catchments areas and is applicable to a wide range of geographic areas. Water samples are taken from three small rivers/streams flow to the Lake Batllava: river Turiqic, river Kushevic and Ballaban, also fr om lake in different depths (5m, 10m and 15m) at different locations. Concerning the environment impact more than 300 interviews were conducted and questionnaires filled in the period October-November for Orllan area, concentrating on the most important issues: building, water supply, wastewater disposal and west disposal. Key words: Lake Batllava, water resources, water supply, water quality, pollution I1TRUDUCTIO1 Many hydrological models have been developed to simulate and help us to understand hydrologic processes. The hydrol ogical models are used as a watershed storm water 11th International Multidisciplinary Scientific GeoConference SGEM2011 www.sgem.org International Multidisciplinary Scientific GeoConference SGEM 2011 986 management tool to provide a direction to utilize natural water resources effectively and beneficially. Water resources in Kosova are relatively small, and the rivers are seriously polluted [1]. The Municipality of Prishtina covers an area of about 450 km² and includes Prishtina Town and some village s. It is estimated that abou t 85% of the inhabitants of Prishtina Municipality live in the urban area, i.e. around 340.000. CATCHME1T AREA OF LAKE BATLLAVA The catchment area of the Lake Batllava ha s a size of 225 km². The ground elevations vary between 600 m.a.s.l. and 1200 m.a.s.l. The catchment area has five main sub- basins. The main sub-basins are further divided into smaller sub-basins. 1. Water balance analysis For monitoring the water levels in the Lake Batllava, using ultra-sonic water level meter located at the outlet stru cture. The water levels in the la ke can be related with the lake storage capacity curve in order to calculate the water volumes in the lake (figure 1). 600 605 610 615 620 625 630 635 640 0 5 10 15 20 25 30 35 40 45 Reservoir storage capacity [x10 6 m³] Elevation [m.a.s.l.] Minimum operation level = 614 m.a.s.l. Maximum operation level = 635 m.a.s.l. Fig.1. Storage capacity curve of Lake Batllava The values were measured at the end of each month. Daily values of the water levels were also available for the period 2007 and 2008. The daily values were compared with the monthly values and no significant differences were det ected. Therefore, the monthly readings are used for preparing the water balance. Based on the available measured data a water balance analysis was carried out for the years 2007 and 2008. In both years the annual water abstraction exceeds the total inflow to the lake by 3.6 x10 6 m³ and 2.9 x106 m³. 2. Hydrological modelling There are presently no operating gauging stations in the catchment area of the Lake Batllava and therefore data on measured infl ow are not available. Information obtained during study in September-October 2009 indi cates that the existing gauging stations were destroyed during the war. Since no usef ul hydrological data was available for the study it was decided to obtain this info rmation by means of hydrological modelling based on a rainfall-runoff computation [2]. The hydrologic modelling system used, is HEC-HMS developed by the Hydrologic Engineering Centre of the US Corps of Engi neers. The model is de signed to simulate 11th International Multidisciplinary Scientific GeoConference SGEM2011 www.sgem.org Hydrology and Water Resources 987 the rainfall-runoff processes of catchment areas and is applicable to a wide range of geographic areas [3]. 2.1. Digital terrain model With the advent of geographic information systems (GIS), digital terrain models have been used to delineate drainage networks and watershed boundaries, to calculate slope characteristics, to enhance distributed hydrol ogic models and to produce flow paths of surface runoff [4] [5]. The basic input information for setting up th e basin model in HEC- HMS is the digital terrain model (DTM) of the area of study. In the course of the study two main sources of data were identified and found suitable for the DTM. Raw data from a recent laser scanning with 10 m raster size was obtained from the Kosovo Cadastral Agency. The second data source consisted in older topographic maps in scale 1:25.000 with contour lines in 10 m intervals. In the areas of the catchment were laser scan data was missing or the data was inconsistent the contour lines of the topographic maps were digitised. 2.2. Basin model The basin model of the Lake Batllava was created using the additional software package HEC-Geom., which is a geo-spatial hydrologic modelling extension for ArcGIS. Basically, HEC-GeoHMS allows to process spatial information, to document watershed characteristics, to perform spatial analyses, to delineate sub-basins, and to create inputs for hydrologic models [3].The first step for creating the basin model is the processing the terrain data. The resulting data sets are used as spatial database for the study.The basin delineation was further processed and refined by determination of watershed characteristics and the run-off situation [6]. The delineation of streams and sub-basins used in the hydrologic model of the Lake Batllava is shown in figure 2. For all sub-basins the following methods for calculating the losses (interception, infiltration, storage, evaporation), transf orm (runoff of excess precipitation) and base flow (sustained runoff of prior precipitation stored temporarily in the watershed) were used: • Loss method: Deficit and constant loss • Transform method: SCS Unit hydrograph • Base flow method: Constant monthly base flow. 2.3. Meteorological model Rainfall data and data on ev apotranspiration were needed for the hydrologic modelling. The data collection conducted in Prishtina revealed that little rainfall data is available from the catchment area. There are no rainfall stations in the catchment area. The rainfall stations Shajkovc and Llug are located outside, 4.0 and 7.5 km west of the Lake Batllava. Daily rainfall values of these sta tions could be obtain ed for 2007 and 2008, only. Because of its closer location to the cat chment area only the data of the Shejkovc station was used for the hydrologic modelling (figure 3). 11th International Multidisciplinary Scientific GeoConference SGEM2011 www.sgem.org International Multidisciplinary Scientific GeoConference SGEM 2011 988 Fig. 2. Sub-basins of the catchment area of the Lake Batllava Jan Apr Jul Oct Jan Apr Jul Oct 2007 2008 Precip (mm) 0 5 10 15 20 25 30 35 40 45 50 Fig. Error! No text of specified style in document.. Daily rainfall at the rainfall station Shajkovc in the period 2007-2008 No data on evapotranspiration in the area of in terest could be obtained in Prishtina. The values used for the hydrologic modelling are shown in table 1. 11th International Multidisciplinary Scientific GeoConference SGEM2011 www.sgem.org Hydrology and Water Resources 989 Table 1 . Monthly average values of evapotranspiration catchment area Lake Batllava Month Monthly average evapotranspiration [mm/month] Jan 1.8 Feb 7.2 Mar 22.2 Apr 49.4 May 95.4 Jun 139.7 Jul 175.7 Aug 144.7 Sep 76.7 Oct 44.3 Nov 19.2 Dec 4.4 2.4. Computation of inflows to Lake Batllava The computed flows are compared against the observed values and the parameter variation is continued until a good relation between model and observations is achieved. In the case of the Lake Batlla va there are unfortunately no measured values of inflows to the lake. The main parameters adjusted during the model calibration are corresponding to the loss module (initial deficit, maximum deficit and constant rate) and the values of the monthly base-flow in the sub-basins [7]. The computed total monthly flows of each main sub-basin and the total catchment area are presented in figure 4 shows a comparison between total monthly inflows to the Lake Batllava computed with the hydrological model and calculated from the water balance analysis. The results in figure 4 show a good overall correlation between computed and observed monthly total inflows to the La ke Batllava. The seasonal vari ations of the lake inflows and the resulting runoff of the rainfall even ts are well described by the model [8]. Special effort was made to obtain a good correlation between calculated and observed total annual inflow to the lake. 3 4 5 6 7 8 otal inflow to the reservoir [x106 m³/month] Fig.4. Monthly total inflow to the Lake Batllava 2007 and 2008 This is evidenced by the small differences of only 6% between computed and observed annual inflows to the lake in the years 2007 and 2008. Relating the computed annual 11th International Multidisciplinary Scientific GeoConference SGEM2011 www.sgem.org International Multidisciplinary Scientific GeoConference SGEM 2011 990 inflows of 2007 and 2008 to the total annual rainfall of the two years leads to the conclusion that the annual total inflow to the Lake Batllava under average rainfall conditions is around 20 Million m³. 3. Water quality Lake Batllava Three small rivers/ streams flow to the Lake Batllava: river Turiqic, river Kushevic, and river Ballaban. In some years water sample s were taken from the streams, just few hundred meters before reaching the lake [9]. Water samples in the lake are taken from three different depths (5m, 10m and 15m) at different locations. Chemical parameters, for which analyses were done, are in general in the acceptable range for raw water for water supply (table 2). These increased values were only found in the lake areas used for recreation, including swimming, e.g. in the Orllan area, but not cl ose to the outlet structure, where the water is abstracted for the treatment plant. In the view of public health, a mo re intensive monitoring during the summer time is therefore recommended, which eventually could lead to a limitation of the recreational activities [10]. Table 2 Water Quality of Lake Batllava Parameter A1 A2 A3 A4 A5 A6 Turbidity (NTU) 1.7 3.2 2.65 4.27 1.84 1.43 pH 7.62 8.61 8.64 7.62 7.74 7.67 NH4-N (mg/L) 0.01 0.02 0 0.01 0 0.03 NO2-N (mg/L) 0.003 0.0129 0.0077 0.0027 0.0043 0.0036 NO3-N (mg/L) 1.4 0.8 2.2 1.7 1.9 1.3 Cl (mg/L) 11 13 11 11 11 11 KMnO4 (mg/L) 8.6 8.36 8.37 15 18.6 9.3 Fe (mg/L) 0.024 0.19 0.084 0.105 0.03 0.043 Hardness (°dH) 11.2 12 11.5 10.08 8.4 8.12 SO4 2- (mg/L) 29.9 65 41 40.7 39.6 38.4 PO4 3- (mg/L) 0.187 0.256 0.218 0.111 0.137 0.064 K (µS/cm) 342 465 438 300 296 291 Mn (mg/L) 0.069 0.014 0.008 0.016 0.003 0.173 Cu (µg/L) 1 1.1 1.9 0.5 0 0 Zn (mg/L) - 0.05 0.009 - - - Al3+ (mg/L) 0.008 0.029 0.019 0.027 0.011 0.04 4. Pollution sources Population concentrates in the village of Orllan, and in the valleys ending in this area. In the valleys of the sub-catchment areas single farms and groups of farm buildings are common. However, estrogens were also det ected in streams in areas with intensive agriculture [11]. During the survey 300 interv iews were held with owners of private houses in the Orllan area, representing approxi mately the total number of buildings of this category (table 3). Lake Batllava was always used for recreation purposes and during the last years a number of new facilities were built and starte d. Numbers of day-visitors and related facilities, e.g. beaches and restaurants increas ed. There is no piped water supply in the Orllan area or elsewhere in the catchment ar ea. More than 60 % of the buildings have their private well, and the others receiv e their water from a tanker truck. The concentrations of estrogens in wastewater treatment plant influents and effluents were 11th International Multidisciplinary Scientific GeoConference SGEM2011 www.sgem.org Hydrology and Water Resources 991 measured in several countries [12]. Two-thirds of the buildings have septic tanks and from the remaining buildings, wastewater is discharged to the field. Table 3. Survey Batllava Orlan, Oct-1ov. 2009, Summary all Buildings Building Persons Water supply Wastewater Disposal Waste Disposal New Seasonal residents employees guests public well water tank septic tank dis. Field container burning nature Private House / Building Total 260 48 70 1.107 0 0 0 167 73 183 55 23 2 212 Percent % 88 18 27 0 64 28 70 21 9 1 82 Shop/ Commerce Total 2 0 0 7 3 0 0 1 1 1 1 2 0 0 Percent % 1 0 0 0 0 0 0 0 1 0 0 Restaurant / Hotel Total 8 0 0 31 27 1.07 0 8 0 0 5 3 0 0 Percent % 3 0 0 0 100 0 0 63 38 0 0 Other Buildings Total 25 0 8 2 52 680 0 21 0 10 20 8 0 0 Percent % 8 0 0 0 62 0 29 59 24 0 0 Grand Total 295 48 78 1147 82 0 197 74 194 81 36 2 212 Percent % 100 16 26 0 67 25 66 27 12 1 72 DISCUSSIO1 A1D CO1CLUSIO1S The annual abstraction of drinking water from the Lake Batllava in the period 2006 to 2008 as shown in Table 3-5 amounts in aver age to about 25 Mill. m³/a. This value corresponds to the maximum treatment capacity of the Water Treatment Plant Albanik of 70,000 m³/d, or 25.5 Mill. m³/a. The results of the modelling show that the minimum, average and maximum total annual inflows to the lake can be expect ed with around 13.5 Mill. m³/a, 19.5 Mill.m³/a, and 52.5 Mill.m³/a, (for low, average and high total annual rainfall). The active storage volume of the Lake Batllav a is assessed to 34.4 Mill. m³. Based on these assessments following conclusions are realistic: • Average annual rainfall generates an inflow of only approximately 78% of the maximum abstraction rate for the water treatment plant, • Assuming average annual inflow over a longer period and the maximum required abstration for the water treatment plant the storage capacity would be exhausted within 5 to 6 years. • In the case of having a long period of extreme low rainfall the storage capacity would be already exhausted after 2 years. In order to obtain more precise results detailed rainfall information is required, meaning records covering 20 and more years. In addition, it is recommended that bacterio logical contamination of the lakes during summer, close to the recreation areas, is mo nitored more regularly, by the institution in charge for this public health issue. 11th International Multidisciplinary Scientific GeoConference SGEM2011 www.sgem.org International Multidisciplinary Scientific GeoConference SGEM 2011 992 In general, buildings should have a septic tank and in filtration pit/soak away for the disposal of wastewater. Direct discharges to fields, drainage channels and water course should not be allowed any longer. For larger settlements, located close to the la kes, most probably a sewerage system will be required in the medium term. This definitely depends on the village/ area development plans and should be investigated in more detail, when the planning of a central water supply system starts. Consid ering these conditions, most likely in the Orllan area at Lake Batllava will become the first area where a sewerage system will be needed. REFERE1CES [1] Avdullahi S., Fejza I., Syla A., Water resources in Kosova. Journal of International Environmental Application & Science (JIEAS), Turkey, Vol. 3, No.6, pp 51-56, 2008 [2] Alcamo J.; Flörke M., and Märker M., 'Future long-term changes in global water resources driven by socio-economic and c limatic change'. Hydrological Sciences Journal 52: 247–275, 2007. [3] USACE User’s Manual, Geospatial Hydrologic Modeling Extension, HEC- GeoHMS, Version 1.1, U.S. Army Corps of Engineers Hydrologic Engineering Center, California, USA 2003, www.hec.usace.army.mil [4] Moore, I. D., Grayson, R.B., and Ladson, A.R.. Digital terrain modelling: A review of hydrological, geomor phological and biological applica tions, Hydrologi cal Process, 1991, Vol. 5, pp. 3-30 [5] Saraf, A.K, Choudhury, P.R., Roy, B. Sa rma, B., Vijay, S. and Choudhury, S. GIS based surface hydrological modelling in identif ication of groundwater recharge zones, International Journal of Remote Sensing, 2004, Vol. 25, pp. 5779-5770 [6] Dixon A.; Butler D.; Fewkes A. and Ro binson M., 'Measurement and modelling of quality changes in stored untreated grey water'. Urban Water, 1(4): 293–306, 2000 [7] Stojov V., Hydrological preview on water resources and water in the central Balkan Region. 25-29 Ohrid, Macedonia, 2004 [8] Avdullahi S., Fejza I., Tmava A., Syla A., “Water Resources of Drini i Bardhe River Basin Kosovo” International Journal of Na tural and Engineering Sciences, Turkey, IJNES 2 (3): pp 105-109, 2008 [9] Korça B, Jusufi S, Shehdula M, Bacaj M, Surface Water Pollution in Kosovo, Scientific Conference: Technical-Technol ogical Sustainable Development and Environment, , pp. 43-49, 2002 [10] Cole, Thomas M. and Herbert H. Hannan. “Dissolved Oxygen Dynamics”, Reservoir Limnology: Ecological Perspectives. Kent W. Thornton, Bruce L. Kimmel, and Forrest E. Payne, eds., John Wiley& Sons, Inc., New York, NY 1990. [11] Kolpin, D. W., Furlong, E. T., Meyer, M. T., Thurman, E. M., Zaugg, S., Barber, L. B. & Buxton, H. T. Pharmaceuticals, hormones, and other organic wastewater contaminants in U.S. streams, 1999–2000: an ational reconnaissance, Environmental Science and Technology, 36(6), pp. 1202–1211, 2002 [12] Koh, Y. K. K., Chiu, T. Y., Boobis, A., Cartmell, E., Scrimshaw, M. D. & Lester, J. N. Treatment and removal strategies fo r estrogens from wastewater, Environmental Technology, 29(3), pp. 245–267, 2008 11th International Multidisciplinary Scientific GeoConference SGEM2011 www.sgem.org

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