Calibrating the Experimental Area Reduction Method in Assessing the Distribution of Sediments in Droodzan Reservoir Dam in Iran

Transcription

1 ORIGINAL ARTICLE Receved 15 Nov. 213 Accepted 3 Ja. 214 Copyrght 214 Scecele Publcato Joural of Cvl Egeerg ad Urbasm Volume 4, Issue 1: (214) ISSN Calbratg the Expermetal Area Reducto Method Assessg the Dstrbuto of Sedmets Droodza Reservor Dam Ira Mohammad Gharaghezlou 1*, Mohse Masouda 2, Robabeh Federesk 3 1 Youg Researchers ad Elte Club, Sar Brach, Islamc Azad Uversty, Sar, Ira 2 Assstat Professor, Departmet of Water Egeerg, Faculty of Agrcultural Egeerg Sar Agrcultural Sceces ad Natural Resources Uversty, Sar, Ira 3 M.Sc Studet of Water Structures Egeerg, Faculty of Agrcultural Egeerg, Agrcultural Sceces ad Natural Resources Uversty, Sar, Ira *Correspodg author s Emal address: gharagezlu_mohamad@yahoo.com ABSTRACT: The expermetal area reducto method s a techque for predctg sedmet dstrbuto dam's reservor ad ts parameters (C, m, ) have bee obtaed by Borlad ad Mller o the formato from a lmted umber of dams Amerca. These coeffcets ca be calbrated for ay other reservors f there s hydrographc formato from the reservor ad the more accurate coeffcets ca be produced for predctos ad programs for water sources. I ths research, s employed the prmary ad secodary hydrographc data of the reservor to calbrate the area reducto coeffcets for Droodza reservor. Therefore utlzg these parameters, the sedmet dstrbuto has bee predcted the followg years. The result demostrates that calbrated parameters make 3% reducto o the amout of errors predctg sedmet dstrbuto. Keywords: Reservor Sedmetato, Area Reducto Method, Droodza Dam INTRODUCTION The purposes of reservors are to store water wet seaso ad to cosume t dry seaso. Therefore, due to water decrease speed ad stagacy, the sedmets are gradually accumulated the reservor ad decrease the volume of the reservor ad evetually ther lfetme. Because of the hgh costs of reservor dams ad the related stallato of water supply, ths volume decrease caot be gored easly, ad t should be preveted to exted the project s useful lfetme. Thus, a umber of methods have bee developed based o preveto ad recyclg reservor volume, the requstes of whch are to kow the volume of put sedmets ad the dstrbuto the reservor (Shafa Bejsta,28). The other problems related to the resdet settlemet cause are the decrease the capacty of retardg flood water, crease the rsk of collapse, decrease the performace of bottom outlets ad dsturbace water takg, crease surface roughess ad the possblty of captato water ways,the eroso of dowstream ad puttg the dam dager ad lower qualty of cosumed water. Therefore, the ssue of sedmets should be cosdered all the steps of dam costructo ad ts mateace (Yag,1996). Havg kow the qualty of sedmet dstrbuto ad predcto, we ca choose the polces of explotg the reservor ad decso makg about the problems caused by sedmets wth hgher cofdece. Sedmet settlemet s ot uform. Wth the researches o 14 dfferet reservor dams doe Ida, the sedmets ofte settle at the upper part of the reservor where the water depth s 2 3 percet of the maxmum reservor depth (Houshmadzaeh et al. 21). Because of the ouform ad complex partcles settlemet, varous methods have bee developed for predctg sedmet dstrbuto the dfferet parts of the reservor. These methods are based o presetg mathematcal models, suggestg expermetal ad sem-expermetal methods or they are based o makg laboratory models, whch are used oly whe there s a eed for hgh accuracy sce they are expesve ad takes tme to do t ad are lmted. Also, the preseted mathematcal models requre several parameters most of whch are hard to measure most reservors or have ot bee measured accurately, but f they exst, they are hghly accurate. May expermetal methods have bee preseted for calculatg the feature of sedmet dstrbuto dam reservors. However, area cremet ad area reducto methods are the most commo (Am et al.21). The base of both of whch s the adjustmet of the reservor s prmary due to the settlemet of sedmets. The cause of the advatages of these 2 methods over the others s that they eed put data. But t has to be oted that these methods do ot cover all the aspects of sedmet settlemet the reservor but they are ecoomcally justfable because they are smple work ad have low costs ad hgh accuracy. The sedmet dstrbuto behd the Zayaderood dam was vestgated usg area cremet ad area reducto methods ad comparg the results of models wth the dstrbuto of sedmet settlemet the reservor showed that Borlad ad Mller model of area reducto method has the hghest smlarty to real sedmet dstrbuto dscrepacy (Mousav et al. 27). To cte ths paper: Gharaghezlou M., Masouda M. ad Federesk R Calbratg the Expermetal Area Reducto Method Assessg the Dstrbuto of Sedmets Droodza Reservor Dam Ira. J. Cvl Eg.Urba., 4(1): Joural homepage: 54

2 Elveto from sea level (m ) The area reducto method was maually calbrated for Golesta dam resultg to a 1 % reducto o error of estmato (Mohammadha ad Emad, 21). The effect of choosg the type of lake o the accuracy of sedmet dstrbuto the Expermetal method of area Reducto method was vestgated Reducto for Doroodza dam, the results show that the proposed method by Borlad ad Mller choosg reservor type was ot relable for the dam (Gharahgezlou et al. 21). Settlemet Sefdrood dam reservor was vestgated usg area cremet method, area reducto method, Gale ad Evas expermetal methods. The outputs these methods are hghly dscrepat from hydrographc amouts ad the methods eed to be calbrated (Kargar ad Sedgh, 29). Of the most promet problem estmatg ad assessg the volume of settlemet the coutry s reservor s the lack of expermetal ad sem expermetal methods attrbuted to reservor calbrato formato Sce the parameters utlzed the expermetal of area reducto method had bee decreased have bee obtaed, accordg to formato studed by Borlad ad Mller 3 dams Amerca, choosg these parameters were hghly fluetal the accuracy of ths method ad sce some reservors of coutry have bee hydrographc the years of explotato, the above method ca be calbrated accurately for every reservor ad every reservor s specfc coeffcets are obtaable. The purpose of ths research s to vestgate the qualty of sedmets dstrbuto Droodza dam reservor usg the expermetal method of area reducto method ad calbrato. Ths method s used for a more accurate estmato ad also ts predcto for the followg years accordg to calbrated parameters. MATERIALS AND METHODS Droodza multpurpose rockfll dam s 1 km orthwest of Shraz o the Kore Rver the logtude ad lattude of 5'', 23 ear Marvdasht cty (Fgure.1). The costructo bega 1959 ad eded The catchmet area s 965 km 2, the crest legth s 7 m ad t s 56 hgh. Fgure 1. Posto of Droodza reservor dam. I ths research, by usg data of the prmary elevato the volume ad area curves of Doroodza dam reservor ad through area reducto method, the sedmet dstrbuto profle was estmated for the year 24 wth the commo parameters of C,m,. the the parameters C,m, were calbrated based o the 24 reservor hydrographc data va a program wrtte the MATLAB evromet, ad t was compared to the real (hydrographc) amout ad the dscrepacy ad stadard devato were obtaed through the relatos. The, by usg the calbrated parameters based o the hydrographc formato, sedmet dstrbuto was predcted for 3 tme perods of (224, 244 ad 264) (Fgure 2) Area(1^6 squre meter) volume(mcm) volume for year1963 Area for year 1963 Fgure 2. Elevato- volume ad area curves of Doroodza dam Area Reducto method smulato The area reducto method s a mathematcal method based o observato prcples reservors whch the accumulato ad dstrbuto of sedmets the dfferet levels have a specfc relato wth reservor s shape. The reservor shape s defed ad categorzed accordg to the heght ad volume of the reservor. I ths method accordg to table 1, the reservors are dvded to 4 types. Table 1. Types of reservor Area Reducto method (Borlad ad Mller 1958; Muterja 1986). M Reservor Shape Type Lake Ι Floodpla II Hll ad Gorge III Gorge IV The bass of categorzg the reservors s M factor whch s coverse of the ddvty of the best drawg le of reservor heght versus reservor capacty whch s draw o a full logarthm paper where the depth s o the vertcal axs ad volume s o the horzotal oe. The ma equato ths method s: )Borlad ad Mller, 1971) S y H Ady y Kady [1] To cte ths paper: Gharaghezlou M., Masouda M. ad Federesk R Calbratg the Expermetal Area Reducto Method Assessg the Dstrbuto of Joural homepage: 55

3 I whch S s the total put sedmets to the reservor durg lfe spa of reservor ad the bottom ad above lmts of the frst tegral cout for the prmary level of the rver bed at the place of costructo before ad after sedmet settlemet, respectvely. A s the reservor area the dfferet elevatos. dy s heght cremet, H s the reservor heght at ormal water level. a s the approxmate area of sedmets whch s measurable accordg to a dfferece, for the approxmate of p, ad k s the proporto coeffcet to chage the sedmet the approxmate area to the real area obtaed from Equato 2. A a K [2] I whch A s the reservor area heght h. a s the sedmet the approxmate area the ew heght zero. The approxmate area s obtaed through formula 3. m a Cp ( 1 p) [3] p Where the measures C, m ad are fxed coeffcets determed accordg to the type of reservor from table 2. Of course, these measures are Borlad ad Mller: corrected measures whch ca be calbrated for each reservor. Table 2. Values C, m ad N o type of reservor Type I II III IV I the area reducto method, for determg the profle of sedmet dstrbuto, the followg steps should be take.(yag, 1996). Step1: The depth of reservor s draw agast ts capacty a logarthmc paper, to determe the reservor shape factor (M) ad the, the reservor type s determed accordgly from table 2. Step 2: The measures of dmesoless fucto h (p) for the dfferet measures of approxmate depth of p are calculated from Equato (4). h'( p) C S V ( y) H A( y) [4] Where h (p) s the dmesoless fucto of the whole settled sedmets, ad the capacty depth ad area of reservor. S s the total volume of settled sedmets. V(y) s the reservor capacty level y ad A(y) the reservor area level of y. Step 3: Based o the relatve depth p ad also F p relato obtaed from the graph Fgure 3, the value/s of h(p) s/are draw the Cartesa system, m where these two curves cross s the ew zero level dam. Fgure 3. Curves to determe the depth of sedmet of dams (Strad ad Pemberto, 1982). Step 4: By usg the reservor s capacty depth curve, the volume of the exstg sedmets uder zero level s determed ad the accordg to Equato1, the sedmet volume the dfferet depths are calculated. It should be otced that ths method s a tral ad error ad f the obtaed sedmet volume has a hgh dscrepacy wth put sedmets, the proporto coeffcet s calculated aga from Equato 5. S K2 K [5] 1 S 1 Where k 2 s the ew proporto coeffcet ad k 1 s the prevous proporto coeffcet ad s 1 s the accumulatve volume of sedmets. The, these measures are compared to those obtaed from hydrograph ad the amout of error ad stadard devato are calculated accordg to Equatos 6 ad 7. e 1 2 ( v v ) [6] 2 ( v v ) /( 1) [7] 1 I whch v ad v are the measured volume ad real volume of reservor the dfferet levels, respectvely. s the stadard devato ad e s the amout of error. RESULTS AND DISCUSSION Table 3 shows the amouts of error ad stadard devato for sedmet dstrbuto usg the Area Reducto method before ad after calbratg parameters (C, m, ) for the sedmet dstrbuto Doroodza dam. Accordg to the table after calbrato, the error decreased aroud 3%. To cte ths paper: Gharaghezlou M., Masouda M. ad Federesk R Calbratg the Expermetal Area Reducto Method Assessg the Dstrbuto of Joural homepage: 56

4 Table 3. Comparg the parameters of Area Reducto method before ad after calbrato Befor Calbrated After Calbrated C M Error(%) v stadard devato Fgure 4 shows the amouts of reservor s volume ad heght 3 modes of the measured, calculated wth commo parameter ad calbrated. As observed from the fgure, the obtaed volume heght graph by calbrated matches the measured amouts better. Ths cocord s hgher upper levels ad s less lower levels, whch s related to calculatg the ew zero level the area reducto method. The ablty of the method of area reducto method predctg the ew zero level wll be foud out here. 8.9 Fgure 4. Measured ad calculated of sedmets dstrbuto profles Fgure 5 depcs the predcto for the sedmet qualty of dstrbuto reservor for the years 224, 244 ad 264 by usg calbrated parameters based o the formato of volume, area ad heght 24. It s see the graph that the put reservor sedmetato s lttle. CONCLUSION The exact data of elevato volume (measured at 24) as well as the prmary data are used to calbrate the parameters of the area reducto techque for the reservor. Thus, through calbratg the parameter caused a 3 percet reducto the error of estmatg the amout ad profle of sedmet dstrbuto. Also, the amout of sedmets ad ts dstrbuto the reservor was predcted for followg years (3 tme perods of 224, 244 ad 264). Based o the result of ths study, the dscrepacy of devato of estmato before ad after calbrato ths method should be calbrated for the other dams that have hydrographc data durg the operato to fd the accurate equatos to estmate the amout ad dstrbuto of sedmets ad set programs for water resources. REFERENCES 1. Am MM.,Bahashem M.E,BehragF, Pourjara ME.(21). Correctg the real data ad makg them ready to use umercal models ad expermetal methos of sedmets' settlemet dams' reservors, case study: Kardeh dam. The 2 th teratoal coferece of dam buldg. Tehra. Ira 2. Borlad WM, Mller CR (1971) Rver Mechacs. I: She HW (ed) water resources publcato, fort Colls, Colorado, USA, Chapter,B 29:Reservor Sedmetato. 3. Borlad WM, Mller CR.(1958). Dstrbuto of Sedmet large reservor. ASCE Hydraulc Dv. 84(2): Gharahgezlou M, Mohammadha A, Emad ER.(211). The effect of choosg the type of reservor o the accuracy of sedmet dstrbuto the expermetal method Area Reducto method Doroodza dam. 9 th coferece of hydraulc. Tehra.Ira. 5. Houshmadzaeh M, shoushtar M, Kashefpour M.(21). Comparg the expermetal methods of Area Reducto method ad area cremet vestgatg the sedmets Karkheh dam reservor. water egeerg,1735: Kargar AE, Sedgh H.(29). Itroducg ad vestgatg the most commo methods for estmatg sedmet deposto dams' reservors (case study: Sefdrood dam). 14 th cogress of cvl egeerg studet. Tehra. Ira. 7. Mohammadha A, Emad ER.(211). Calbratg the expermetal method of Area Reducto method estmatg sedmets dstrbuto Golesta reservor dam. 5 th cogress of cvl egeerg. Mashhad. Ira. 8. Mousav SF, Haydarpour M, Shabalou S.(27). Ivestgatg sedmets Zayadehrood dam usg the expermetal methods of Area Icreamet ad Area Reducto method. Water ad wastewater. 124: (76), Mutreja KN (1986)Appled Hydrology,Tata Mc Graw-HILL,New Dehl,p959 Fgure 5. Predcted of sedmet dstrbuto profles To cte ths paper: Gharaghezlou M., Masouda M. ad Federesk R Calbratg the Expermetal Area Reducto Method Assessg the Dstrbuto of Joural homepage: 57

5 1. Shafa Bajesta M.(28). theory ad practce of hydraulcs of sedmet Trasport. 2d, Shahd Chamra Uversty Ira, p Strad RI, Pembrto EL (1982) Reservor Sedmetato, Bureau of Reclamato, Deever Colorado. 12. Yag CT.(1996). Sedmet Trasport: Theory ad Practce, Mc Graw-Hll,New York,pp396 To cte ths paper: Gharaghezlou M., Masouda M. ad Federesk R Calbratg the Expermetal Area Reducto Method Assessg the Dstrbuto of Joural homepage: 58