           !" # ) 2 )  #( 5 ( # !( 1393 56             ! " !# $% & #’ (   Numerical Model of Contaminant Transport in Rivers with Dead Zone Using Fractional Calculas Abbas Parsaie 1*, Mohammad Mehdi Ahmadi 2 , Kurosh Qaderi 3 1    )## *+  &# ,+  - .’ &/(  2    )## *+  &# !’’( ’ ,+ .  ’(0$12+’ 3    )## *+  &# !’’( ’ ,+ .  3’4(2+’ *Corresponding Author (Abbas_parsaie@yahoo.com) Article History Received: 06 February 2014 Reviewed: 21 February 2014 Revised (1) : 24 February 2014 Revised (2): 03 March 2014 Accepted: 08 March 2014 Published: 15 June 2014  In this study a numerical model has been presented for solving fractional advection7dispersion equation(FRADE) in rivers with dead or stagnant zone. The FRADE equation is solved numerically with finite diference method useing a time splitting technique for solving advection and dispersion terms separatly. Analytical solution of modified advection dispersion equation model (MADE) and observed data from Severn river in U.K. were used to demonstrate the model capabilities. There is a good agreement between the observed data, analytical solution of MADE model and FRADE model. The fractional model characterized by the FRADE can accurately simulate the long7tailed dispersion processes in natural rivers.  Advection7 Dispersion, Dead Zone, Fractional, Numerical Model, River            ! "# $ $ %&’ ()* (’ + 1 #- &#! . 2 0 1 . 3 1 .3 %& 4 .5 46 .$ 7 .8 49 :$ 49 &//052+’ 2 .3 %& 4 .5 46 49 8 .%$ ;&< ’(0$12+’ 3 %& 4 .3 .5 46 49 8 .%$ ;&< ) 3’4(2+’ ( : @A 02 / 12 / 1392 :EFA @A 17 / 11 / 1392 H  IJA : @A 25 / 03 / 1393 :1AK’ @A 17 / 12 / 1392 LMN @A ) 1 ( : 05 / 12 / 1392 LMN @A ) 2 ( : 12 / 12 / 1392 ,-. A)* OJ’ H $ "A  P- $   ) FRADE .( $   EQRS H T! Q%    P- $ .E 4T< 4 T $ :AT<   H  .K  4VT 7F 7  1 5  .ET 4T< P- %#TW 1 $ OJ’ X;%I# ";%6 5 Time Splitting  P- Y; $ OJ’  H  F 4&$ E!N $ .E 4<    Z% 4< 4 ); ;< [A J’ H  \;!] 1 R;R! P- 5 PN- [A $  5 O ) MADE ( 4 5 4V $ X;%I#    4< E<$  Severn 8 $ [A .E 4< AH 8R9  3 E0 4% 4< 4  Q  $ ;< QRS 5   E   .E $ %&’ / :1,2 1 H ^ $ %&’ .OJ’ . 1 .   . * $ _ &/  6 7777(     ! " !# $% " ’ & 5 "88"         ISSN 2345 7 5012