The impact of global warming on water resources (Case Study: Sirvan River Basin)

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1 The mpact of global warmng on water resources (Case Study: Srvan Rver Basn) M.Gholzadeh, F.Ghader, M.Bayazd, M.Kak Abstract In recent decades, human actvtes have caused ncrease n the concentraton of greenhouse gases and consequent global temperature ncrease. The temperature rse also affected clmatc varables and caused clmate change, and consequently, the hydrologcal regme of rvers has changed. In ths study, non-parametrc Mann-Kendall method trend analyss at the level of 95% was used. Also, slope examnaton of the trend lne San non-parametrc estmator methods were used. For ths purpose, the and ranfall data of seven ran gauge statons and four statons n Srvan Rver Basn durng the perod ( ) were used. Also usng the Thessen method n GIS average annual ranfall and n the rver basn of Srvan obtaned and trend checkng wth the nonparametrc test was also done them.. The results showed that the amount of ranfall annually n Palangan staton and n Takhan staton mm s decreased and the amount of annually n the Palangan staton and mm ncreased n Takhan staton. Most sgnfcant changes n temperature and ranfall n southern Palangan staton hot and cold perods have occurred. In examnng the slope of average ranfall and trend n the basn t was ndcated that rate of was ten tmes ranfall durng the last three decades and has had the an upward trend. Keywords: global warmng, ranfall,, clmate change, Srvan Rver BBT Pub. All rghts reserved. Introducton In recent decades, human actvtes have caused ncrease n the concentraton of greenhouse gases and consequent global temperature ncrease. Scenaros publshed by Intergovernmental Panel on Clmate Change (IPCC) ndcate that the temperature of the planet by the year 2100 wll ncrease C compared to Ths ncrease also affects other Clmatc varables and causes clmate change (Blkng Sap and Fuller, 2007). By clmatc varables changng, hydrologcal regme of rvers and consequently frequency and severty of droughts may also change. It has been noted n several studes (Bunce, 1993). On the other hand, gven that Iran s located n ard and sem-ard areas s often prone to drought and water resources of surface and groundwater are affected and n perods of drought damage and varous soco-economc consequences occurs. So far, many studes assessng the clmate ranfall changng system and hydrologcal flow varable usng trend analyss s conducted ncludng, (Luo et al., 2008) ranfall trend of Bejng rver basn n Chna at 63 statons and 7 sub-basn was examned as quarterly and annually durng the perod ( ) n 17 tme seres (monthly, quarterly, annually, dry season, etc.) usng Mann -Kendal method. Ther results showed that there s a declne n ranfall n sprng and monsoon and ncrease n ranfall n wnter and autumn. Carrera et al. (2007) wth Temporal and spatal analyss of daly and monthly ranfall and temperatures n the Basn of Mexco found that daly temperatures nterpolaton usng the heght factor as the second varable helps the valdty of estmatons; however, t s possble these two varables have a weak correlaton. (Caloero et al., 2009) Studed seasonal and annual ranfall trend n Calabra (southern Italy) usng nonparametrc tests (Mann-Kendall) and parametrc (lnear regresson analyss).. The results showed that autumn, wnter and annual ranfall n southern Italy show a decreasng trend and summer ranfall show an ncreasng trend. Rahm Zadeh et al (2011) studed evaluatng ndex mutaton of temperature trend and ranfall n the Hormozgan provnce; the results show that the ncrease of heat and reducton of ranfall n the provnce has been along wth an ncrease n volatlty n ranfall and temperature lmt values. (Chrst, et al., 2011) examned the relatonshp between clmate and rver flow n fve hydrometrc statons of Karkheh rver n Iran. They showed that n some months an ncreasng trend (as of December) and others have experenced decreasng trend (lke May). They often attrbuted ths trend to changes n ranfall. (Esmaeelpour and Dnpajouh, 2011) examned Changes n ranfall n the Sarab desert wth the monthly ranfall data n the perod ( ), usng the Classc and modfed Mann-Kendall. Ther results ndcated that there s a declne n ranfall n dfferent tme scales n Sarab desert area. Of studes n the feld of meteorologcal varables trend (Tabar and Marouf, 2011, Atae and Fane, 2012) can be ponted out.in ths study whch s done by the mpact of global warmng on water resources goal, so to acheve ths goal the changes clmatc varables trend ranfall and on Srvan Rver Basn study n the tme seres of monthly, quarterly and annual and also checkng changes n the average of ths two parameters wll be conducted n the basn durng the past three decades. Materals and Methods The study area Srvan Rver Basn wth an area of 7500 square klometers s consdered the most waterful basns n Iran and Kurdstan. So that 8.2 bllon cubc meters of surface water n ths area s flowng. Srvan Rver wth a length of 213 klometers s consdered one of the largest and most waterful rvers of the provnce. Rver such as Garran, Gheshlagh, Gordlan and Razab are of the most mportant rvers n ths basn. Ths rver s located n the western

2 M.Gholzadeh et.al / Teknolog Tanaman /Vol (12), Supp (2) and northwestern of Uraman and dvded Uraman area nto two sectons. Ths rver orgnates from the Razab and Marvan n Kurdstan and after passng through the Northwest of Uraman, Doab and North Herta, Zhadrood, the Gheshlagh rver, Llle, Lueshe, Zamkan, Dasht Hor rvers jons t and then goes to Iraq. Ths rver basn partcular topographcal and morphologcal condtons n the Srvan basn provded mplementaton of mportant economc projects n the area ncludng the constructon of large dams to rrgate agrcultural lands, energy generaton, fshng, aquaculture, toursm and large ndustres that requre a lot of water. Sanandaj Gheshlagh dam wth a capacty of 224 mllon cubc meters s one of exstng dams that supply water to the cty of Sanandaj. Currently dams of Gavoshan wth volume of 550 mllon square meters and Garan dams n Marvan are under constructon and Zarvar dam n order to ncrease the volume of lake from 35 mllon cubc meters to 90 mllon cubc meters s constructed wth a heght of 5 meters. In general, Srvan Basn by beng next to the major ctes such as Sanandaj (captal of the provnce) and cty of Marvan n the Iraq border n terms of water resources has great potental and can mprove the economc ndcators n the provnce. Ths basn d med of sub-basns of Sanandaj, Marvan and Sarvabad. Ran gauge and of Mnstry of Energy statons poston s shown n Fgure 1 and also the statons specfcaton n the Srvan Rver Basn s gven n Table 1. Fgure 1 Srvan Rver basn poston n the Iran s basns and under study statons Table 1. Statons Specfcaton n the rver basn of Srvan Row Statons Rver Type Statc perods Longtude (degree mnute) Lattude (degree mnute) 1 Kajkaran Gheshlagh Pluvometry Hussen Abad Gheshlagh Ran gauge and TAZEHABAD Gheshlagh Pluvometry Sarab Gheshlagh Ran gauge and Sanandaj Gheshlagh Pluvometry Khoruse Shushe Pluvometry Pnjon Shushe Pluvometry Sarcheshmeh Garan Ran gauge and Takhan Garan Pluvometry Zarvar lake Zarvar Ran gauge and Palangan Srvan Ran gauge and Shlan Gavehrood Pluvometry Under study data Snce n clmate change studes long-term statstcs evaluaton can greatly show changes and clmatc characterstcs, theree the long-term ranfall and evaporatng monthly data n seven ran gauge statons and four statons n Srvan Rver Basn over the 30-year perod ( ) was used. Table 1 shows the statons specfcaton. Dfferent methods envronmental varables trend analyss s presented among these methods, correlaton and regresson analyss methods, tme seres analyss and nonparametrc tests can be

3 496 M.Gholzadeh et.al / Teknolog Tanaman /Vol (12), Supp (2) 2015 mentoned. In ths study, to evaluate annually, quarterly and monthly ranfall and evaporatng trend n all selected statons n the Srvan rver basn nonparametrc test (Mann-Kendall) and calculatng the slope of the trend lne the San estmaton test was used. Mann-Kendall Non-parametrc Mann-Kendall test s consdered one of the most common methods of hydrologcal and meteorologcal seres trend analyss. Several studes done usng ths method show the mportance and wdely use n the tme seres trend analyss (Hajjam et al., 2008). Ths test frst n 1945 was presented by Mann and then n 1948 was developed by Kendall. The use of ths method was recommended by the World Meteorologcal Organzaton. The method hypothess randomness of data sequence test s used aganst the exstence of trends (Khall and Bazrafshan, 2004). Of the strengths of Mann-Kendall method ts approprate use tme seres that do not follow a partcular dstrbuton, can ponted out. Neglgble nfluence of lmt values n ths method whch are observed n some tme seres s one of other advantages of ths method (Hajjam et al., 2008). The null hypothess of ths test on randomness and lack of trend of data seres mples and acceptance of assumng a (the null hypothess Rejectng) s evdence of trends exstence n data seres. Z score of the test s determned by the followng mula: s 1 v ( s ) z 0 s 1 v ( s ) s 0 s s 0 0 S statstcs calculaton method and ts varance are as follows: s n 11 n 1 j 1 sgn( x j x ) In the above equaton sgn(x) s the sgn functon and s defned as follows: 1 sgn( x ) 0 1 x 0 x 0 x 0 v ( s ) n ( n 1)( 2 n 5 ) m 18 1 t ( t 1)( 2 t 5 ) In ths test In case of statstc Z beng postve, data seres trend, upward and f t s negatve s downward and also Z statstcs at the level of 5% ts sgnfcance the amount was Trend slope rand (Sen Estmator) Ths method (Sen, 1968; Syl, 1950) s used to determne the amount trend slope. In ths method outler values n the data seres, have lttle effect n determnng the slope of trend whch s the man advantage of t compared to the lnear regresson. Ths ndcator s dsplayed by β and ts value s estmated usng the followng equaton: In whch gk s slope estmator k-th staton n g-th month. Postve values of gk ndcate an ncreasng trend and ts negatve values represents a decreasng trend. gk Medan X gk X j jgk, 1 j n Thessenzng of the under study area For better examne of two under study varables trend, the average of annually ranfall and temperature n the study area were classfed by Thessen that better cover the basn ranfall n Thessen, seven ran gauge statons (Shlan, Palangan, Takhan, Tazehabad, Sarab, Hossen Abad and Sarcheshmeh) fve evaporatve statons (Hussen Abad, Sarab source, Nagel and Palangan) were used and accordng to mula (relaton 5) average was calculated. Fgure 2 shows the Thessen classfcaton of ranfall and. P: Average ranfall staton (mm). a : effect level of staton (m) p: average basn ranfall (mm)

4 M.Gholzadeh et.al / Teknolog Tanaman /Vol (12), Supp (2) Fgure 2: Thessen Classfcaton of Srvan Rver Basn Results and Dscusson Annually and seasonal trend of changes In Table (2 and 3), Mann-Kendall test results (Z) and Sen (Q) under study statons was provded. As you can see, based on the Mann-Kendall annual ranfall n Palangan, Shlan, Hossen Abad, Sarcheshmeh and Takhan statons decreasng trend and also n Palangan staton had sgnfcant decreasng trend at 5% level. But n two Tazehabad and Sarab statons n the eastern part of the basn (the Sanandaj area) had ncreasng trend and a sgnfcant ncreasng trend n Sarab- staton occurred at 5%. Downward trend obtaned by annually changes of research results (Lou et al., 2008), matches whch examnes Mann Kendall and Sen's estmaton methods conducted n Bejng Rver n Chna. In the Palangan staton n the West of basn n the annual seres and fall, wnter and sprng seasons sgnfcant decreasng trend was observed. For the evaporatng varable at Palangan, Sarab and Hossen Abad statons an ncreasng trend and n Palangan staton sgnfcant trend have experenced at 5% level. Accordng to Fgure 4, that average evaporatng n the basn usng Thessen n the basn level was observed. Trend ncreased wth a slope of mm and the trend examnaton wth the Mann- Kendall statstc value of (Z) equal to 78.5 showed sgnfcant ncreasng trend that showed exstence of sgnfcant trends n the annual and average tme seres of evaporatng n the basn by ncrease n temperature n the regon.. Based on the slope of the lne that presented n the tables (2 and 3), t can be concluded that the amount of annual ranfall n the Palangan staton and mm n Takhan staton s decreased and the amount of annual at Palangan staton and n the Takhan staton s ncreased by mm. Accordng to the results of the nonparametrc test seres of seasonal ranfall has decreasng trend For 50% Seres and the evaporatng varable at Sarab-, Hossen Abad and Sarcheshmeh statons n the eastern and western parts of the basn have ncreasng trend. And ths trend n the sprng at the level of 5% sgnfcant had experenced a sgnfcant ncrease. Also Accordng to sprng trend lne slope of varable of Hossen Abad staton ncreases 5.77 mm per decade. Table 2. The results of the Mann-Kendall and Sen For ranfall Staton Annual Autumn wnter Summer Sprng Z Q Z Q Z Q Z Q Z Q Palangan Shlan Tazehabad Sarab Hossen abad Sarcheshmeh Takhan trend s at the 5% level sgnfcance. Table 3. The results of Mann Kendall tests and Sen Staton Annual Autumn wnter Summer Sprng Z Q Z Q Z Q Z Q Z Q Palangan Sarab Hossen Abad Sarcheshmeh trend s at the 5% level sgnfcance. Monthly Changes trends Mann-Kendall test results monthly ranfall and evaporatng n under study statons are provded n tables (4 and 5).. Decreasng trends n monthly ranfall n Palangan statons n all data except July, August and September whch no rans occurred n these months were determned by nonparametrc test and n January, March and June

5 Ranfall(mm) 498 M.Gholzadeh et.al / Teknolog Tanaman /Vol (12), Supp (2) 2015 sgnfcant decreasng trend have been found.. But n Sarab- staton February a sgnfcant ncreasng trend and n other statons and months of the year have shown a varable ncreasng or decreasng trend. The results of the monthly ranfall trend lne slope at all statons except Sarab staton n Gheshlagh Rver that s consdered branches of Srvan rver showed decreasng trend. The most amount of sgnfcant trend ncrease was related to the amount of 99.3 of Sarcheshmeh staton and the greatest number of sgnfcance trend was related to Palangan staton both varables. Zero values of lne slope n the trends (Sen Estmator) whch n some months, can be seen n the staton ndcates that a partcular trend n ths seres of data over the past three decades haven t been acheved. Due to the lne slope of trends table (6), The most changes of monthly evaporatng were observed n Hossen Abad and Sarcheshmeh staton n Aprl and May n the study perod. So that the evaporatng of Hossen Abad staton 9.39 mm per decade n July and also n Sarcheshmeh statons Aprl and June was found the of 22.4 mm per decade. Table 4. Mann-Kendall test monthly ranfall Staton October November December January February March Aprl May June July August September Palangan Shlan Tazehabad Sarab Hossen abad Sarcheshmeh Takhan trend s at the 5% level sgnfcance. Table 5. Mann-Kendall test the monthly evaporatng Staton October November December January February March Aprl May June July August September Palangan Sarab Hossen abad Sarcheshmeh trend s at the 5% level sgnfcance. Table 6 Sen estmator slope monthly ranfall statstcs Staton Octob er Novem ber Decemb er Januar y Febru ary March Aprl May June July August Septembe r Palangan Shlan Tazehabad Sarab Hossen abad Sarcheshme h Takhan Table 7. Sen Estmator slope monthly statstcs Staton October November December January February March Aprl May June July August September Palangan Sarab Hossen abad Sarcheshmeh x y 0.10 = ²R Tme(year) Fgure 3. The average ranfall n the Srvan rver basn

6 Evaporaton(mm) M.Gholzadeh et.al / Teknolog Tanaman /Vol (12), Supp (2) y = x R = ² 0.81 Tme(year) Fgure 4. The average evaporatng n rver basns Srvan Concluson In ths study, by usng ranfall and evaporatng data trends detecton n Srvan rver basns durng the perod ( ) were studed. The analyss of trend of clmate varables temperature and ranfall n all of the monthly, annual and seasonal seres at the southern and eastern parts of basn showed that t has had reduced ranfall and ncreased evaporatng over the past three decades. Also accordng to the average annual ranfall and evaporatng from Thessenng the surface of the Srvan rver basns ndcated that slope the ftted regresson lne the ranfall data s ncreased 2.47 mm per decade, but s ten tmes the amount of evaporatng data,ths means that t has ncreased by the amount of 5/471 mm per decade. Also n examnng annual ranfall and evaporatng seres trend n the South Staton (Palangan) they experenced decreasng trend by 3/158 mm and 3/264 mm ncreasng trend. In the eastern part of the basn (Sanandaj) changes n the temperature s lower and the most changes has been n ranfall and evaporatng varable n the southern and western statons. Sgnfcant changes n evaporatng n Hussen Abad and Sarcheshmeh statons n the warm perod had a postve trend. Snce ths area s one of the most mportant areas n Kurdstan provnce n terms of water resources theree, management and water wthdrawals from rvers, the amount of water taken from reservor dams n the basn and provsons that are agrcultural purposes and aquaculture n the utlzaton regon s necessary. References 1- Khall, Al and Bazrafshan, J. (2004), analyss of annual precptaton, the seasonal and monthly trends of fve old staton n hundred and sxteen years n Iran, Baban, 9 (1), Esmaeelpour, Marzeh and Dnpajouh, Jacob (2011), analyss of changes n precptaton on the Dasht Sarab by usng Mann- Kendall classc and refned test, the Natonal Conference on clmate change and ts mpact on agrculture and the envronment, the second Urma August. 3. Rahm Zadeh Fatemeh and Hedayat Dezful, Akram and Poorasgharan, Arezoo (2011), trend mutaton evaluaton of ranfall and n Hormozgan provnce, Geography and development Magazne NO.21, P Hajjam, Sohrab, Khoshkhu, Yunus and Shamseddnvendy, R. (2008), analyzng trend of changes n the seasonal and annual ranfall of some statons n central areas of Iran by usng non-parametrc methods, Geographc Research 64, Tabar, Hussen and Marouf, Safdar (2011), revealng trend of changes n Maroon rver dscharge by usng parametrc and nonparametrc methods. Geographcal Research Journal 26, Blenknsop S., and Fowler, H.J (2007) Changes n drought frequency, severty and duraton the Brtsh Isles projected by the PRUDENCE regonal clmate models. Journal of Hydrology, 342: Bonacc O (1993), Hydrologcal dentfcaton of drought. Hydrologcal Processes, 7: Sen, P. K (1266), Estmates of the regresson coeffcent based on Kendall s tau. Journal of Amercan Statstcal Assocaton, 63: Luo, Y., Lu, Sh., Fu, S., Lu, J.,Wang, guoqn, &Zhou, G (2008), Trends of Precptaon n Bejang Rver Basn, Guangdong Provnce, Chna, Hydrologcal Processes., 22, Carrera-Hernandez, J. J. and Gaskn, S. J., 2007, Spato temporal analyss of daly precptaton and temperature n the Basn of Mexco, Journal of Hydrology, 336: Bouza-Dean, R., Ternero-Rodrıguez, M. &Fernandez-Espnosa, A.J (2008), Trend study and assessment of surface water qualty n the Ebro Rver (Span), J. Hydrol., 361, Caloero, T, Coscarsll, R, Ferrar, E&Mancn, M (2009), Trend detecton of annual and seasonal ranfall n Calabra (Southern Italy). Internatonal Journal of Clmatol, vol31, No Mash. I. Uhlenbrook. S. &V.Smakhtn (2011), Streamflow trend and clmate lnkages n the Unted States. Journal of clmate, 7, Matt, C, Paulng, A, Kuttel, M& H, Wanner (2009), wnter precptaton trends two selected European regons over the last 500 years and ther possble dynamcal background. Theoretcal Appled Clmatology, 95: M.Gholzadeh, Assstant Professor Department of Ecology Unversty of Kurdstan, m.gholzadeh@uok.ac.r F.Ghader, PhD student n Ecology and a vstng lecturer at Department of Ecology the Unversty of Kurdstan Regonal Group, E-mal: fatemeh_1522@yahoo.com M.Bayazd, Assstant Professor, Department of Water Engneerng, Islamc Azad Unversty of Sanandaj, m.byzed@gmal.com M.Kak, MA Water Resources Management, mehrykak67@gmal.com