BURSA İLİNİN SU VE ATIKSU POTANSİYELİNİN DEĞERLENDİRİLMESİ

Kentsel buyume tatlisu kaynaklarina olan ihtiyaci artirmaktadir ve su kentler icin dikkate deger bir oneme sahiptir. Hizli buyuyen mega kentlerin pek cogu kirlilik, otrofikasyon, atiksu aritimi eksikligi ve belki de en onemlisi temiz su eksikligi gibi ciddi su ile ilgili problemlerle karsi karsiyadir.   Dunyanin tum kentsel kisimlarinda su kaynaklari verimsiz bir yolla kullanilmaktadir. Bursa,  icme suyu ve genel kullanim suyu temini acisindan Turkiye’nin en zengin kentlerinden biridir. Tatlisu kaynaklarinin disinda Bursa kenti termal su kaynaklari acisindan da zengindir. Bursa, su kaynaklari ve atiksu aritim faaliyetleri acisindan cevreye duyarli su yonetim sistemi ve ileri goruslulugu ile ornek bir sehirdir. Bu calismada, Turkiye’nin Guney Marmara Bolgesi’nde bulunan ve zengin su kaynaklari ile onem arz eden bir metropolitan kent olan Bursa su tuketimi ve su kaynaklari acisindan degerlendirilmektedir. Calisma kapsaminda atiksu aritim faaliyetleri de belirtilmistir. Calisma sonucunda Bursa’daki su kaynaklarinin ve atiksu aritim servislerinin gelistirilmesi ile ilgili cozum onerileri verilmistir.


INTRODUCTION
World water reserves are steadily declining. According to the studies, in 10-15 years, many cities will be faced with the threat of drought, and this situation will pose a serious threat to small regions that have less than 1000 m 3 of water (Sivanappa,2006;Goel and Patel, 2006).
Although covered with water three quarters of the world, the appropriate amount of fresh water for human use is very limited. The total amount of freshwater on Earth about 35 million km 3 (ie 2.5 % of the total water on Earth) and only 0.3 % is composed of freswater resources which are suitable for the ecosystem and human use ( Figure 1). The reamining freshwater, were tarpped mostly poles, glaciers located in high mountains and under ground reservoirs.

Figure 1. Water Distribution on the World
The general objective of this study was to assess and review the existing water and wastewater services and to identify priority areas, that can help in developing strategies and programs for improving quality of the water supply services in case of Bursa city.

TURKEY'S WATER POTENTIAL
Contrary to the general perception, Turkey is neither a country rich in freshwater resources nor the richest country in the region in this respect.
Turkey is situated in a semi-arid region, and has only about one fifth of the water available per capita in water rich regions such as North America and Western Europe. Water rich countries are those which have 10000 m 3 /year. This is well above the 1500 m 3 /year in Turkey.
One of the global scale environmental pollution problems of Turkey is temporospatial uneven distribution of water resources among the regions. Water resources of Turkey aren't located in the right place at the right time to meet present and anticipated needs of the region. Certain regions of Turkey such as the Black Sea region have ample but unusable freshwater, while some of the highly populated and industrialized regions such as the Marmara and the Aegean regions lack sufficient fresh water.
Water potential of Turkey was shown in Figure 2. According to hydrometeorological data during 1951-2000 annual avarage rainfall depth was 643 mm/year and it corresponds 501 km 3 . 55% of rainfall (274 km 3 ) backs to atmosphere by evaporation, ~14% (69 km 3 ) of feeds groundwater and 31% (158 km 3 )of reaches sea and lake by flow (MFWA, 2008). 28 km 3 (~ 41%) of 69 km 3 water which feeds surface waters and groundwaters backs to the surface water by fountains. 41% ( 28 km 3 ) of water fed subsurface and ground water includes into surface water by fountains. Total annual flow is 186 km 3 (158+28 km 3 ). In addition, ~ 7 km 3 of water comes into country from neighboring countries. Therefore gross surface water potential reaches to 193 km 3 . In assuming the groundwater feeds (41 km 3 ), renewable water potential of country could be estimate as 243 km 3 /year. Within the scope of technical and economical conditions, surface water potential which will be consume for several purposes is 98 km 3 including domestic run off (95 km 3 ) and flows from neighboring country (3 km 3 ). Annual draw-off groundwater potential was estimated as 14 km3 (~34% of total) technically and economically. Therefore, current available surface and grounwater potential can be assumed as 112 km 3 , and 40 km 3 of available water potential (~36% of total) is used already (Ayaz, 2010).

Figure 2.
Water Potential of Turkey (Ayaz, 2010) Municipal water use accounts for about 15% of total water use in Turkey, compared to 75% used by agriculture and 10% by industry. Total water withdrawals for all uses accounted for only 17% of total available water resources in an average year (average 1977-2001). Municipal water use thus accounted for only about 3% of available water resources. However, water availability is highly seasonal and there is not a uniform water distribution throughout the country. Local and regional water scarcity occurs despite ample average water availability (RTMD, 2001) Located in northwestern Anatolia, within the Marmara Region Bursa is the fourth most populous city in Turkey with a population of 2842547 and one of the most industrialized metropolitan centers in the country (TSI, 2016). Its surface area is 10891 km² and altitude is 155 m. Bursa exerts a significant impact upon the national economy of Turkey as being a centre of both agricultural and industrial production. According to the industrial activities, it takes part in the second order after İstanbul and 13th order in the Turkey's general situation. It is known with many sectors such as textile, automotive, manufacture, agriculture based industry and food, furniture and machine-metal. The sectoral distribution of industry in Bursa (in 2000) is as follows: service is 40%, agriculture is 33% and industry takes part 27% (CCIB, 2003).
As being one of the most important and agricultural center of Turkey, during the past two decades, substantial migration into the region has increased drastically. Huge population masses migrated and settled in Bursa as a result of various wars beginning from the end of the 19th century. The migration from rural to urban areas of about 1.4 million people per year shows adverse effects, which are felt heavily in Ankara, Bursa, Istanbul, Izmir, Adıyaman, Antalya, Diyarbakır, Batman and İçel (OECD, 1996).
Bursa is one of the wealthiest cities in terms of drinking and general purpose water resources in Turkey. The water of Bursa may be grouped into two as drinking and general use and as thermal springs. Despite the rich resources of water, Bursa is facing some problems along with the increasing urbanization and industrialization.

POPULATION AND WATER DEMAND
The increase in the population of the cities also causes the increase in the total water for adequate municipal supply (Falkenmark and Widstrand, 1992 Bhatia and Falkenmark, 1993). This total municipal water demand growth is not just because of the increase in urban population, but also because of a tendency for economic development. This economic development also increases the fraction of the urban population that uses municipal supply rather than other sources such as local wells or private water vendors (Bartlett, 2003; Howard and Bartram, 2003).
Municipal supply is generally cleaner and safer than other water sources, so actually, increasing access to municipal supply for the world's poor is one of the Millennium Development Goals (Howard and Bartram, 2003). Furthermore, economic development which brings urbanization increases water use per capita (Posteli et al., 1996). The overall increase in total municipal water demand causes cities to search for new adequate, relatively clean water sources, leading to the creation of sometimes quite complex systems of urban water infrastructure (Alcott et al., 2013;Brown et al., 2009;Chau, 1993;McDonald et al., 2014 ) The average water consumption per capita is 158 L/day in Bursa City. However, because of the 30% of water loss within the distribution network, gross water consumption per capita is accepted 226 L/day (BUWSA, 1992, Akal Solmaz et al., 2003). Distribution of water demand by year in Bursa City is given in Figure 3.

CURRENT SITUATION OF WATER RESOURCES IN BURSA
Bursa is one of the few cities owing both superficial and underground water resources. The city's water supply is provided by three sources. These are superficial water resources, (Nilüfer Creek, Doğancık Dam), groundwater services and fountains. Due to the data of 2004, water supply system is 5845000 m 3 /day from Nilüfer Creek, 360000 m 3 /day from groundwater services, 1277000 m 3 /day from fountains and totally 7482000 m 3 /day (Yalılı and Akal Solmaz, 2004). The annual water resources capacity and percentage distribution of water resources of Bursa City is given in Figure 4 and Figure 5, respectively.

Percentage Distribution of Water Reusorces of Bursa City
As it is shown in Figure 5, Nilüfer Creek which is one of the most important river of Marmara Region has a great importance as a source of drinking water. Also Nilüfer Creek is faced to discharge of wastewater from all kind of industries, as a result of discharges, Nilüfer Creek consists of serious pollution.
Nilüfer is a subbasin of Susurluk Basin, that has a flow potential of 5.43 km 3 /year and has also 3% of the water potential of Turkey's rivers. Figure 5 shows the location of Bursa in Turkey Map.
According to Water Supply Master Plan Report of Bursa City, four dams are planned to be constructed namely Doğancı (S. Saygı), Nilüfer, Çınarcık and Gölbaşı Dam for drinking water supply. Doğancı (S. Saygı) Dam is the major drinking and domestic water resource of city. The height of Doğancı Dam is 65 m and the body of dam consists of rock and soilfill. Although it is an open system and it interacts with many environmental factors, the quality of water is suitable for Quality Criteria of intracontinental water resources classes which are given in Water Pollution Control Regulations (WPCR) since its location is far away from industrial and municipal area. Nilüfer Dam which is consists of rock fill has a 72.5 m height and supplies drinking and domestic water demands of city. Çınarcık and Gölbaşı Dams are serving for other purposes apart from drinking and domestic water uses.

The Location of Bursa in Turkey Map
Bursa and Çayırköy Plains can be assumed as the groundwater potential of Bursa City. Bursa Plain has annually 147.8 hm 3 recharge and discharge capacity. 80% of this capacity (118.2 hm 3 ) is used by Bursa Municipality and several enterprices as drinking and domestic water. In addition, Bursa Plain water reserves are assigned to discrete cooperatives for irrigation purposes. The annual recharge and discharge capacity of Çayırköy Plain is 10.1 hm 3 and 70% of this capacity is used. The major use areas of the reserves of Çayırköy Plain are irrigation and drinking water purposes (GDSHW, 1994).
As a result of climate change, permanent drought or water stress can be seen in some regions even in a water abundant city such as Bursa. The groundwater resources were used in 2014 when there was a water scarcity throughout the city.

Sewerage Collection System
While the majority part of the city has already had a separate sewerage system which collects storm water and sewage with different pipe lines, separate collector systems are under construction in some parts of the city. The length of sewerage system in Bursa City center including Osmangazi, Yıldırım, Nilüfer, Gürsu and Kestel Districts is about 2762000 km. BB (concrete pipe), BA (concrete pipe) and HDPE (high density poly etylen) types of pipes have been used in the system. Diameters of concrete pipes vary between Ø300 and Ø2000 mm. Cast manhole covers are used. Bursa City Center and the municipal adjacent areas of Bursa Metropolitan Municipality have 1061000 km stormwater collector systems. The stormwater system project of the other areas have been completed, and the system will be constructed within the program. The diameters of stormwater collection pipes varies between Ø400 and Ø1600 mm (BUWSA, 1992).

Municipal Wastewater Treatment
In Bursa, 5 wastewater treatment plants (WWTP) namely Western, Eastern, Çalı, Kayapa and Hasanağa have been operated by Bursa Water and Sewerage Administration General Directorate (BUWSA). The percentage of wastewater from urban area is treated by Western and Eastern WWTP is 95%. In Eastern WWTP, municipal wastewater from Osmangazi and Yıldırım districts are treated with capacity of 240000 m 3 /day while Western WWTP treats municipal wastewater from Nilüfer with capacity of 87500 m 3 /day. Domestic wastewater from Gürsu and Kestel, industrial and domestic wastewaters from Kestel Organized Industrial District and domestic and industrial wastewaters from Kestel and Barakfakih Organized Industrial District are treated together by wastewater treatment plant operated by Green Environment Treatment Plant Management Cooperative, which is an association of the relevant municipality and the companies located in region. The capacity of Karacabey and Çalı WWTP are 9600 and 1000 m 3 /day, respectively. In addition, two domestic wastewater treatment plants have been operated in Hasanağa and Kayapa Housing Development Administration of Turkey (TOKI) districts. Three more wastewater treatment plants have been planned to be constructed for the areas with a population of over 2000, namely Akçalar, Gölyazı ve Badırga areas (Ayaz,2010).

Industrial Wastewater Treatment
There are seven (7)

CONCLUSIONS
Bursa is a water rich city with high capacity of surface waters and groundwaters except from other thermal water resources, and the unique city posses these speciality. Prescinding the high water capacity of Bursa, an evaluation has been done in terms of potable water and water resourses. As a result of the study, it has been concluded that water resources meet the demand of the city within the 20 years time. However, being a migration-receiving city in case of an unexpected increase in population, the planned water resources should be put into use gradually, water treatment plants should be built, and the deficiencies of distribution systems should be completed.
Reclamation and reuse of treated wastewaters have become a significant component of municipal, regional and national water management. The United Nations is compelling the countries to develop new water management strategies due to the threat of water shortage within 10 years. Wastewater reclamation and reuse topics are gaining importance, against limited water resources and increasing water demand, not only in dense population cities but also in rural areas as well.
Bursa is a metropolitan where dense industrial facilities take place and also rich for agricultural activities that it is one of the major cities which meets the food demand of Turkey. 230 792 m 3 /day industrial wastewater is being discharged into the surface waters after being treated in Bursa. Hence, treatment of wastewater should be carried and controlled carefully in order to reuse it in agricultural irrigation. Water Pollution Control Regulations Technical Methods Declaration-Appendix 7 (20 March, 2010; no: 27527) should be considered while treatment of wastewaters for purposes of agricultural irrigation reuse.