REUSE OF DRAINAGE WATER PROJECT

Transcription

1 REUSE OF DRAINAGE WATER PROJECT Evlution reuse of dringe wter from the Umumthment for extension of griulturl lnds in the Western Desert C.WJ. Roest M.A. Abdel Khlek Adel Abdel Rshid Amr El Shfie Reuse Report

2 ABSTRACT Roest, C.W.J., M.A. Abdel Khlek, A. Abdel Rshid & A. El Shfie, Evlution of reuse of dringe wter from the Umum thment for extension of griulturl lnds in the Western Desert. Ciro (Egypt), Dringe Reserh Institute, nd Wgeningen (The Netherlnds), DO Winnd String Centre. Reuse of Dringe Wter Projet Report pp,; 29 Figs; 8 Tbles; 4 Refs. The SIWARE model hs been pplied to the Western Delt nd Desert Regions in Egypt to study the onsequenes of extension of new griulturl lnd in the Western Desert with or without dditionl reuse of dringe wter from the Umum dringe thment. In the model simultions the totl fresh wter supply hs been kept onstnt for the different lterntives. The model simultions reveled tht extension of the totl griulturl lnds with bout 8% ppers profitble under the ondition tht the dringe wter from the Umum is dded to the wter supply in the Western Desert. An dditionl extension with 11 % ppered to be not profitble under the hosen boundry ondition of onstnt fresh wter supply. The effets of reuse of dringe wter from the Umum thment on the slinity of the drinking wter supply in West Alexndri hs been inluded in the study. Keywords: wter mngement, slinity, lnd relmtion, reuse of dringe wter; evlution of lterntives DRAINAGE RESEARCH INSTITUTE (DRI), P.O. Box 13621/5, Qnter, Ciro, Egypt, phone: ; fx: ; telex: 2275 WRC UN nd DO Winnd String Centre for Integrted nd, Soil nd Wter Reserh (SC-DO), Postbus 125, 67 AC Wgeningen, The Netherlnds; phone: ; fx: ; telex: 7523 VISI-N Projet 8576

3 CONTENTS 1 INTRODUCTION 1 2 DEFINITION OF SIMUATION RUNS 3 BASIC ASSUMPTIONS 5 4 SYSTEM RESPONSE TO AND RECAMATION AND REUSE OF DRAINAGE WATER Wter blne System behviour Soil nd wter slinity Drinking wter slinity 5 SEECTION OF PROJECT ATERNATIVES 31 6 CONCUSIONS 37 ITERATURE 41 FIGURES 1 yout of the proposed Umum Reuse projet 2 2 Nile wter supply in m 3.feddn' for the extension strtegies 7 3 Computed rop évpotrnspirtion for the short term strtegies 9 4 Computed dringe wter flowing to the se for the short term strtegies 9 5 ong term retion of évpotrnspirtion to lnd relmtion nd reuse of dringe wter 1 6 ong term retion of dringe to the se to lnd relmtion nd reuse of dringe wter 11 7 Totl vilble reuse of dringe wter for Umum reuse phse I nd phse I & II projets 11 8 Opertionl losses form the min irrigtion system in the Western Nile Delt for the strtegies studied 14 9 Computed quntities of muniipl wter supply for the short term extension nd reuse strtegies 15 1 Computed unoffiil reuse of dringe wter by frmers for the short term extension nd reuse strtegies Computed spill losses from distributry nls for the short term extension nd reuse strtegies Computed totl rop wter supply for the Western Nile Delt for the short term extension nd reuse strtegies Computed reltive hnge in totl rop wter supply for the strtegies studied Computed reltive hnge in rop wter supply per feddn for the strtegies studied 18

4 15 Computed min irrigtion nl system performne for the strtegies studied Computed irrigtion distrit system performne for the strtegies studied Computed rop system performne for the strtegies studied 2 18 Computed overll system performne for the strtegies studied Computed long term overll system performne for the strtegies studied 22 2 Computed long term hnge in rop irrigtion wter slinity for the strtegies studied Computed long term hnge in rop dringe slinity for the strtegies studied Computed long term hnge in lekge slinity for the strtegies studied Computed trend in soil slinity for the strtegies with extension of 165, feddns Computed trend in soil slinity for the strtegies with extension of 35, feddns Computed (long term) effet of lndrelmtion nd Umum reuse projet phse I & II on drinking wter slinity from Mhmudey nl Computed (long term) effet of lndrelmtion nd Umum reuse projet phse I & II on drinking wter slinity from Nubrey nl Computed slinity profiles long Nubrey nl for 165, feddns lnd relmtion nd three options for reuse of dringe wter Computed hnge (long term) in évpotrnspirtion in the desert s result of lnd relmtion for three lterntives of reuse of dringe wter Computed hnge (long term) in évpotrnspirtion in the delt s result of lnd relmtion for three lterntives of reuse of dringe wter Computed hnge (long term) in évpotrnspirtion Western Nile Delt s result of lnd relmtion for three lterntives of reuse of dringe wter 34 TABES 1 Wter supply redution per unit re for the different strtegies 4 2 Frtion of vilble dringe wter whih n be withdrwn for reuse 6 3 Computed overll short nd long term wter blne Western Nile Delt 8 4 Computed short term system behviour for the strtegies studied 12 5 Computed long term system behviour for the strtegies studied 13 6 Computed short nd long term slinity rop wter blne omponents 23 7 Computed long term évpotrnspirtion in the old lnds nd new lnds s result of the different extension nd reuse strtegies studied 32 8 Computed wter supply redution (Nile wter & reuse of dringe wter) per unit re for the different strtegies studied 37

5 1 INTRODUCTION In the frmework of the Reuse of Dringe Wter Projet the SIWARE model hs beendeveloped s toolfor ssisting wter mngementdeision mkersin plnning wter resoures nd supply in the Nile Delt in Egypt. Initilly, during Phse I of theprojet, thesiware model wspplied tothe Estern Nile Delt (Abdel Gwd et l, 199). In theseond phseofthe projet pplition ofthe modeltothe MiddlendWestern Delt prts ws undertken. Before pplying simultion models for the nlysis of wter mngement lterntives, suh models should be thoroughly librted nd vlidted. For the Western Nile Delt this hs been hieved (Abdel Khlek et l, 1995). For the librtion yer the dishrges were onsidered suffiiently urte for 85%of the re nd for 75% of the re the simulted slinity ws stisftory. Vlidtion ws less suessful (Abdel Khlek et l, 1995). The min reson for this limited vlidtion of the model for the Western Delt s ompred to the Estern Delt (Abdel Gwd et l, 199)nd the Middle Delt (Smitet l, 1995)most probblyis the disturbing ftor of hnging piezometrilevelsin the quifer inthe Western Desert, whih isnot inluded in the SIWARE model (Abdel Khleket l, 1995). As onsequene the omputed results of wter mngement lterntives should be exmined utiously. Computtions should ertinly not be onfused with the rel onsequenes of wter mngement lterntivesfter implementtion. Nevertheless, omputtion resultsmybeusedfor themutulomprison oflterntives.devitions in the model results due to onsistent devitions in quifer pressures will propgte to ll omputtion results nd be less disturbing if ompred mutully. Inthe presentreport the usefulness of thesiwaremodel for the mutul omprison of lterntive wter mngement strtegies will be demonstrted. In order to dhere to present wter mngement problems of the Ministry of Publi Works nd Wter Resoures (MPWWR), the Umum Reuse projet hs been seleted s se study. The Ministry of Publi Works nd Wter Resoures is developing plns for reusing dringe wterfrom theumummindrin tosupplement wtersupply through Nubrey nl for new lnd extensions in the Western Desert. Aording to these plns ontrol struture will be build in the Umum drin downstrem of the onfluene of Trug pump sttion into the Umum drin (fig 1). By reversing the diretion of dringe wter flow in the Umum drin until Shereshr pump sttion nd pumping the wter through Shereshr drin nd Sidi Eiss drin to Nubrey nl t Km 46, the dringewterfrom bout 293, feddns (fig 1)nbe reused in thenew lnds of the Western desert. In previous study of DRI, it ws estimted tht bout 1,1 million m 3 of dringe wter ould beome vilble for irrigtion by this projet (Msknt, Abbs nd Kndil, 1985). This figure of over 1 billion m 3 ws bsed on the verge dringe flows through the period 198/1984.

6 < ^ MEDITERRANEAN SEA Mx P.S.1 Abies P.S. y / WU-8 "' El Ql P.S.?v \ y// m f hr«p S V'Dishudi P.S. WU é Äf- WU " 5 Reuse Dishudi Bridge N WU-4 -»Anwr Bridge > x / o 1 S* *<"6; *>î ^ Nubry Are llqmriut P.S. / u WU-1 ƒ % ^ // l 3 m Pr P sed S\ / <Jjrug P.S V WU - 3 V # <è Reuse «fi \\ <*/ '»/ 'W i / Sheresher Bridge vu.îns ISheresher P.S. WU-2 \ 4? '<< '< '' > /"- "h. P.S. no 2 i 48m3.s-i, V/ <? ; Abu Hommes..Are N, P-S no 1 ' P.S. no 3 48m3.s-i 39m3 s -1 C^ Si. ''<%>. ^ ^.Pr/n km // " ">» Drin (Projet Proposi) Dringe Cnl Irrigtion Cnl Drin Under Constrution Cthment Are Boundry Pumpsttion O Reuse-Pumpsttion A Open Drin otion Open Drin Reuse otion Rod ^S Figure 1 yout of the proposed Umum Reuse projet

7 2 DEFINITION OF SIMUATION RUNS The present griulturl re in the Western Delt (sitution 199)is pproximtely 1,714, feddns, of whih 677, feddns hve been relimed in the Western desert (west of the Nubrey nl). Beuse some 93, feddns in the Western desert were relimed in 199, but not yet ultivted, the tully ropped re in the Western Delt mounted to roughly 1,621, feddns in 199, with bout 584, feddns in the Western desert. For the extension of griulturl lnd in thewestern Delt severl plns rein preprtion or under onstrution. In the present study two lterntives for extension of griulturl lnd were ssumed. In the first lterntive n extension with 165, feddns is ssumed nd for the seond lterntive n extension of 35, feddns of netgriulturl lnd.for bout 93,feddns no relmtion worksre required, this ws the fllow re in 199. This would inrese the totl rurl griulturl in thewestern desert from the present 677, feddns to 749, feddns for the first lterntive nd to 934, feddns for the seond lterntive. Thetotl ropped re for the omplete Western Delt (inluding the new lnd) would then inrese from the present (199) 1,621, feddns with 1% to 1,786, feddns for the first lterntive nd with 21.5% to 1,971, feddns. All dditionl new lnds in the Western desert will be ssumed to be irrigted by sprinkler systems nd the wter requirements of the Ministry of Publi Works nd Wter Resoures for sprinkler irrigted rops will be used. Itisnot expeted thtthetotl Nilewter resoures for Egypt will inrese onsiderblyinthenerfuture. Inthepresent study,therefore, nodditionl Nile wter supply hsbeen ssumed tobeomevilble for the Western NileDelt. Theonly dditionl wter resoure onsidered will be the dringe wter from the Umum Reuse projet. Three lterntives for dditionl reuse of dringe wter will be onsidered in the present study (tble 1): no dditionl reuse; reuse of the dringe wter of the Umum drin thment untilndinluding theonfluene ofshereshr pump sttion (Umumprojet phse I);nd reuseofdringe wterfrom theumumdrin thment until nd inluding the onfluene of Trug pump sttion (Umum projet phse I &II). Tking the wter supply in 1989 of bout m 3.yer' s referene nd subtrting the drinking nd industril wter requirements of bout m 3.yer" 1, n vilble griulturl wter supply of m 3.yer"' results. Aording to Msknt, Abbs nd Kndil (1985), the Umum projet phse I results in n dditionl reuse of dringe wter resoure of bout m 3.yer ' nd Umum projet phse I & II in bout m 3.yer" 1. Bsed on these figures the redution in the griulturlwter supplyfor thedifferent simultion runsn belulted (tble 1). Redutionsintul wtervilbility ofup to 18%reinluded inthe lterntives studied.

8 Tble 1 Wter supply redution (Nile wter & reuse of dringe wter) per unit of re for the different strtegies studied (%). extension griulturl re (feddns) reuse of dringe wter no dditionl reuse option Umum projet phse I Umum projet phse I & II ode redution ode redution ode redution 165, 35, (.) 1 (165,) (35,) (165,5) 3.2 (35,5) 12.3 (165,1) -1.8 (35,1) 7.7 '- the first numberintheodereferstotheextensioninthousndsoffeddns;theseondnumberrefers tothedditionlreuseofdringewter:5inditesphse IoftheUmumprojet; 1inditesphse I &IIof theumumprojet. Comprison of the lterntives mentioned in tble 1 will be minly bsed on the hnge in évpotrnspirtion in the existing old lnd nd in the relmtion re. Evpotrnspirtion is diretly relted to rop yields. Due to the differenes in soil fertility between theold lndsnd the newly relimed griulturl res évpotrnspirtion hs to be onsidered seprtely for both res. In ddition to rop yields, effets on soil slinity will lso be evluted seprtely, beuse sliniztion of thesoil is slowly inresing proess whih is quite diffiult to reverse in the hevy ly soils in the old lnds of the Western Nile Delt. To this purpose lso the long term effets of these strtegies will be evluted. Alexndri drinking wter supply is from Mhmudey nl nd will therefore not be ffeted by reuse of dringe wter in the Desert re. Mixing of dringe wter will tke ple in the Nubrey nl, whih lso serves Mriut nd Borg El Arb drinking wterpump sttions.with dishrges of3. nd4.6m 3.s _1 respetively, they supply bout 15% of the drinking wter for thewestern Nile Delt. In the SIWARE model only the totl slinity of irrigtion wter is simulted. Other wter qulity prmeters ntherefore notbestudied. Thedeteriortion of the drinking wter slinity for the lterntives studied will be evluted seprtely.

9 3 BASIC ASSUMPTIONS The sitution with respet to wter supply nd initil onditions for 1989 will be tken s strting point for the nlysis of the 6 wter mngement lterntives. For thereferene senrio theropping pttern of 199 hs been tken. In order to reuse the dringewterfrom theumum drinin the Western desert re,the infrstruture needs to be dpted. For this purpose reuse pump sttion hs been modelled in the Umumdrin downstrem of Shereshr pump sttion. Thisreusepumpsttion delivers its dringe wtert Km 48in the Nubrey nl. A seond reuse pump sttion hs been modelled intheumumdrin downstrem oftrug pump sttion.alsothis reuse sttion is supposed to deliver its dringe wter t Km 48 in the Nubrey nl. Twolultion unitsdriningtoshereshr ndtrugdringepump sttions reeive their irrigtion wter from Nubrey nl fter Km 48, i.e. fter the new mixing lotion.sinethesiware modelnnot hndlethere-irultion of dringe wter from its own thments, speil brnh nl, tking wter from Nubrey nl upstrem of the mixing point tkm 48,hsbeen modelled for these two lultion units. Due to this limittion, the slinity of the dringe wter from Shereshr nd Trugpump sttionswillbeslightlyunderestimted. Thesetwolultion units form bout 1% of the thment of the Umum drin, providing dringe wter for reuse to Km 48 in Nubrey Cnl (29, feddns out of 293, feddns). Bsed onthemounts ofdringe wterpumped bythedifferent reuse pump sttions in the Western Nile Delt for 1989, the frtions of the vilble dringe wter in these drins whihn bereused will befixed (tble 2). Fortwo grvity drins, drin No 3 nd drin No 6, whih return their flows to Nubrey nl, these frtions re equl to unity. It will be ssumed for ll simultion runs tht these drins will ontinue to return their omplete flows to Nubrey nl. For the two new reuse pump sttions in the Umum drin the frtion of the dringe wter they re ble to withdrw hve been rbitrrily fixed t.7 for the winter period nd.9 for the other periods (tble 2). The totl Nile wter supply of 1989 for the Western Nile Delt will be fixed t million m 3 nnully. The distribution of this quntity over the different dedes of dys,however, will lso depend onthe distribution of the vilble dringe wter over the different sesons. A free distribution of irrigtion wter in time hs therefore been ssumed, following the offiil wter requirements of the different rops ording to the duties used by the Ministry of Publi Works nd Wter Resoures. The wter requirements for drinking nd industril wter will be ssumed identil to those for 1989 t 1,333 million m 3 nnully. Bsed on the bove ssumptions referene run hs been mde. A similr run hs lso been performed for long term (5 yers) in order to detet ny trends in the wter nd slt blne due to initil non-equilibrium onditions.

10 Tble 2 Frtion of vilble dringe wter whih n be withdrwn for reuse frtion of vilble dringe wter whih n be withdrwn for reuse reuse lotion winter 1 period spring/utumn 2 period summer 3 period Ety Brud PS.5 Edko Irrigtion PS.4 Dilingt PS 1. Khndk Ghrbi PS.7 Mriut Khlt PS.1 Bustn PS.7 Imtedd PS.8 Drin No 3 1. Drin No 6 1. New pump sttions (2).7 winter: Jnury nd Februry summer: My, June, July nd August spring/utumn: remining months

11 SYSTEM RESPONSE TO AND RECAMATION AND REUSEOF DRAIN AGE WATER Simultion resultsn be nlyzedfor the ompletewestern Deltin orderto investigte hnges in the system effiieny nd behviour. This will be done in hpters 4.1 nd 4.2 respetively. Also long term trends in soil slinity n be nlyzed for the omplete Western Nile Delt. This is treted in hpter Wter blne Thetotlwter supply tothe Western Delt inludingthe relmtion reis ssumed onstnt. Per feddn of ultivted rop this mens tht the totl Nile wter supply, expressed inm 3 perfeddn redues from roughly bout 6,4m 3.feddn" 1 with bout 9% till 5,8 nrlfeddn" 1 for the extension with 135, feddns nd with lmost 18% till 5,25 m 3.feddn * for the extension with 35, feddns (fig 2). 1 "O TS ) m E D 1BD -I9QD 2D Z1Ü Totl ultivted re Western Nile Delt Cfeldns* 1 Figure 2 Nile Wter supply in m 3.feddn' for the extension strtegies Due tothe extension of new lnds in the Desert res thefirst yer of implementing suh extensions shows n inrese in the soil moisture storge. This is notied in the totl blne of the simultion results (tble 3). This devition is lrgest with theextension of35,feddns ndimplementtion of theumum phse I & IIreuse projet.

12 Tble 3 Computed overll wter blne Western Nile Delt in million m 3.yer' for the Vmum reuse projet lterntives with two options for extension of the griulturl re in the Western Desert. Both the short term blnes (first yer) s well s the long term (fter 5 yers) re given. The slinity of the dringe wter is given in the lst olumn. ode 1 Nile wter supply Gins/ losses 2 ground wter Evpotrnspirtion Dringe to Se Inrese in storge Dringe slinity (g-m 3 ) Short term blnes (,) (165,) (165,5) (165,1) (35,) (35,5) (35,1) ong term (fter (,) (165,) (165,5) (165,1) (35,) (35,5) (35,1) 5 yers) blnes ,42-1,182 5,741 5,787 5,861 5,965 5,794 5,883 5,984 5,721 5,724 5,811 5,922 5,698 5,797 5,93 4,581 4,134 3,936 3,695 3,75 3,523 3,272 4,62 4,163 3,958 3,716 3,774 3,544 3, ,692 1,775 1,89 1,782 1,853 1,9 1,89 1,77 1,842 1,866 1,836 1,979 2,15 1,99 '- the first number in the ode refers to the extension in thousnds of feddns; the seond number refers to the dditionl reuse of dringe wter: 5 indites phse I of the Umum projet; 1 indites phse I & II of the Umum projet. 2 - seepge plus ground wter use minus lekge Extension of the griulturl re results in lrge inreses of losses to the ground wter system in the simultions.when dringe wter is reused these losses beome even lrger (tble 3), beuse more wter is vilble for irrigtion in these res. Evpotrnspirtion by rops lsoinreses whennewres retken into ultivtion. These hnges re smll ompred to the hnges in losses to the ground wter system (fig 3). The dereses in dringe wter dishrges omputed by the model of up to 1,2 million m 3 for the senrio with 35, feddns of dditionl new lnd nd the Umum reuse projet phse I & II (fig 4) re therefore minly used by irrigtion wter losses in the Desert re nd only to very limited extent by the inrese in rop évpotrnspirtion. This is onfirmed by the limited inrese of bout 15%in the long term in dringe wter slinity flowing to the se (Tble 3). This phenomenon beomes even more ler when exmining the reltive hnges in volumes of rop évpotrnspirtion nd dringe for the long term simultions. Without dditionl reuse of dringe wter from the Umum projet nd extension of griulture with bout 1% (135, feddns), totl évpotrnspirtion, whih is orrelted to totl rop prodution, inreses with less thn 1% (fig 5). 8

13 m E 65 BOOG - i M B5 / / r i_ +j ( > CU i_ o 5BDD C / ^""^ _ tn Extension in Desert Cfeddn * 13 -B-HO dditionl reuse -e Umum reuse Phse I -h-umum reuse Phse I I too Figure 3 Computed rop évpotrnspirtion for the (short term) strtegies studied Extension griulturl lnd Cfeddns*1G3 -B-No dditionl reuse -e-umum Phse I -A-Umum Phse I I Figure 4 Computed dringe wter flowing to the se for the (short term) strtegies studied

14 E 4-1 ( m 1 i_ 4-1 O ( > i o U dj ( x: u 5 1D 15 Extension griulturl lnd C%3 No dditionl reuse -O-Umum Phse I Umum Phse I I Figure 5 ong term (fter 5 yers) retion of totl évpotrnspirtion (in %) to the different extension of griulturl lnd (in %) options for three lterntives of inresed reuse of dringe wter Whenthenew lnds reinresed with 22% (35, feddns) totlrop évpotrnspirtion even dereses slightly. Dringe dishrges derese with 28nd 38% respetively for these lterntives. Even with dditionl reuse of dringe wter the totl reltive évpotrnspirtion inreses with only 2 to 4% when extending the griulturl re with 1%, nd slightly less when the inrese in re is bout 22% (fig 5). For the sme senrios the dringe dishrge redues up to 4% (fig 6). Bsed on this performne (fig 5) it n be onluded tht extension of griulturl re with more thn 165, feddns bsed onthe existing wter resoures doesnot seem to be good investment. Extension ombined with using the dditionl reuseof dringe wter resoure from the Umum drin my or my not be profitble, depending on the investment ost nd on the reltive vlue dded in the new Desert res, where prodution is inresed, ginst the existing old lnds, where prodution dereses s result of these mesures. Theseresults should be interpreted refully, beusethey rebsed onmodel simultions. The extension ofnew rehs been ssumed to tke pleon orse textured soils nd n on-frm irrigtion effiieny of 75% for sprinkler rops hs been ssumed. Moreover, on the long term it n be expeted tht ground wter levels will rise, thereby reduing lekge losses. In themodelonstntpiezometri pressures hve been ssumed. 1

15 1Ö r. u Extension griulturl lnd C? No dditionl reuse -o-umum Phse I -Umum Phse I I Figure 6 ong term (fter 5 yers) retion of dringe flow to the se (in %) to the different extension of griulturl lnd (in %) options for three lterntives of inresed reuse of dringe wter E 'E 1B / ^ ^ <U 4-> IÜ S ) r r 4- i in <u 16D / / " / ^ ^ ^ ~ / s ^ r u o B [ 1 2 3D Extension in Desert Cfeddns*1QO -B-no dditionl reuse -6-Umum reuse phse I -A-Umum reuse Phse I I AC Figure 7 Totl vilble reuse of dringe wter for the Umum reuse phse I nphse I & IIprojets, bsed on totl Nile wter supply of million m 3.yer~' nd two lterntives for ultivting dditionl lnd in the Western desert 11

16 4.2 System behviour Applition of omprehensive model suh s the SIWARE model to regionl wter mngement systems offers the opportunity to investigte hnges in wter blne omponents, whih re otherwise diffiult to exmine. The retion of the system to hnging wter mngement is importnt to know beforehnd. In previous studies (Msknt, Abbs nd Kndil, 1985) it ws estimted tht bout 1,1 m 3 dringe wter would be vilble for reuse. This estimte ws bsed on dringe mesurements during the period 198/1984. In the present study it n be seen tht the vilble dringe wter depends on the extension of griulturl re itself (fig 7; tble 4 nd tble 5). Keep in mind tht the totl Nile wter supply hs been kept onstnt for these strtegies. Tble 4 Computed short term irrigtion system performne for the lterntives of extension of griulturl lnd nd reuse of dringe wter studied in the Western Nile Delt. Wter blne omponents re given in million m 3.yef' nd system performne in perentges item ode: (,) (165,) (165,5) (165,1) (35,) (35,5) (35,1) Nile wter supply Offiil reuse Opertionl losses 1 Muniipl wter supply 923 1,72 1, ,32 1,263 1,346 1,54 1,29 1,94 1,95 1, ,75 1,198 1,298 1,86 1,222 1,746 1,13 1,245 Distrit wter supply Unoffiil reuse Spill losses 8, ,137 8, , , ,127 9, , , Crop wter supply 2 8,786 9,193 9,432 9,748 9,49 9,731 1,2 Evpotrnspirtion 5,741 5,787 5,861 5,965 5,794 5,883 5,984 Min system performne 3 Distrit performne 4 Crop performne' System performne inluding the onveyne losses from the min irrigtion system 2 - inluding 334 million m'.yer" 1 of ground wter use 3 - defined here s the sum of Distrit wter supply plus muniipl wter supply divided by the sum of Nile wter supply nd offiil reuse of dringe wter 4 - defined here s the rop wter supply divided by the sumof the Distrit wter supply, the unoffiil reuse, nd ground wter use 5 - defined here s the évpotrnspirtion divided by the rop wter supply 6 - defined here s the sum of évpotrnspirtion plus muniipl wter supply divided by the Nile wter supply 12

17 Tble S Computed long term irrigtion system performne for the lterntives of extension of griulturl lnd nd reuse of dringe wter studied in the Western Nile Delt. Wter blne omponents re given in million m'.yef' nd system performne in perentges item ode: (,) (165,) (165,5) (165,1) (35,) (35,5) (35,1) Nile wter supply Offiil reuse Opertionl losses 1 Muniipl wter supply 926 1,72 1, ,26 1,263 1,349 1,47 1,289 1,94 1,89 1, ,64 1,195 1,298 1,76 1,221 1,716 1,9 1,245 Distrit wter supply Unoffiil reuse Spill losses 8, ,138 8, , , ,13 9, , , Crop wter supply 2 8,788 9,227 9,473 9,779 9,549 9,799 1,99 Evpotrnspirtion 5,712 5,724 5,811 5,922 5,698 5,797 5,93 Min system performne Distrit performne Crop performne System performne '- inluding the onveyne losses from the min irrigtion system 2 inluding 334 million m'.yer" 1 of ground wter use 3 defined here s the sum of Distrit wter supply plus muniipl wter supply divided by the sum of Nile wter supply nd offiil reuse of dringe wter defined here s the rop wter supply divided by the sum of the Distrit wter supply, the unoffiil reuse, nd ground wter use defined here s the évpotrnspirtion divided by the rop wter supply defined here s the sum of évpotrnspirtion plus muniipl wter supply divided by the Nile wter supply When no dditionl reuse of dringe wter infrstruture is onstruted the vilble quntity of dringe wter for reuse redues upon extending the griulturl re in the Western desert. Due to wter lloted to these new res, the existing 'old lnds' reeive less irrigtion wter nd onsequently produe less dringe wter (fig 7). The sme trend n be observed for the situtions with dditionl reuse infrstruture, by ompring the lterntive of 35, feddns of extension with tht of 165, feddns of extension in the desert (fig 7). The dditionl wter vilble through the Umum reuse phse I & II projet mounts to bout 1, million m 3.yer" 1 when 165, feddns re relimed dditionlly nd bout 85 million m 3.yer' when 35, feddns re relimed (tble 4). Upon extension of the griulturl re the opertionl nd onveyne losses tend to be lowered initilly. For the seond inrese of griulturl lnd from 165, till 35, feddns, the opertionl losses inrese (fig 8). The reson for this phenomen is tht initilly the til-end losses from the min nl system were redued onsiderbly. In ll ses the onveyne losses in the Desert re use n inrese of this blne omponent. This is onfirmed by the observtion tht for the situtions 13

18 with the Umum reuse projet phse I & II in opertion the opertionl nd onveyne losses ontinue to inrese for both phses of extension of griulturl lnd. m E 'E 11DD in to w o Q) 1 ffl Q) U ( 19-1B D5D ^^r^^^^^ ^ \ s^ : ^ ^ ^ > o 12 C Extension in Desert Cfeidn * 1 -B- No dditionl reuse --Umum reuse Phse I -A-Umum reuse Phse I I 4 Figure 8 Opertionl losses from the min irrigtion system in the Western Nile delt for the strtegies studied. Opertionl losses re defined here s the sum of til-end losses nd onveyne losses Aording to themodel simultions lso the muniipl wter supply willbe ffeted by the impliit redution in totl wter supply due to the extension of griulturl lnds (fig 9).It should be kept in mind tht themjority of drinking wter pump sttions re loted ner the til-end of the Mhmudey nd Nubrey nls. Suh redutions re not eptble,of ourse. In this respet themodel simultions should be regrded s wrning tht speil mesures sfegurding the drinking wter supply re wrrnted when strtegies suh s those studied here re onsidered. When onfronted with wter shortges, frmers lookfor ny vilble wter to supplement their needs. Generlly,frmers loted t the til-endsofnls nd mesks re the first to suffer from wter shortges. In suh ses, whenever they re ble to ess it, they use dringe wter. This use of dringe wter for irrigtion by frmers is lled unoffiil reuse of dringe wter. When lnd relmtion in the Western desert is implemented, keeping the totl wter supply onstnt, wter shortges in the 'old lnds' will inrese. As onsequene, unoffiil reuse of dringe wter is expeted to inrese. The SIWARE model simultions indite the sme trend (fig 1). Upon implementtion of the Umum reuse projet phse I or phse I & II, the simulted unoffiil reuse of dringe wter dereses drstilly. This is in onformity with the erlier studies (Msknt, Abbs nd Kndil, 1985) where itwsestblished through field observtions thtfrmers longtheumummin drin were frequently using this wter for irrigtion of their fields. 14

19 m E i Q. u ui ) (Ü ä 1 u D D - ^^^E~-~^lr^^-\ ^ ^ ; : : : : ^ ^ S 1D 2DD 3 Extension in Desert Cfeddn * 15 -e-no dditionl reuse - >-Umum reuse Phse I -A-Umum reuse Phse I I 4DD Figure 9 Computed quntities of muniipl wter supply for the (short term) extension nd reuse strtegies studied m E R- ^ -fj E ^j 73 OJ in 3 QJ I U ^ D 69 ^*^^ \s^ ^ _ ~ ~ ~~ I I I Extension in Desert Cfeddn * 1GO -e-no dditionl reuse -è-uiïium reuse Phse I I -S- Umum reuse Phse I 4 Figure 1 Computed totl mount of unoffiil reuse by frmers for the (short term) extension nd reuse strtegies studied 15

20 -I2D r~\ 11 E 1D ^ ~ *. N ^ \. \. - \ ^ \ ^ \ E UI t U) u) 9DD BOD V) 7 : \ ^ \ 1 2D 3D Extension in Desert Cfeddn * 13 -e-no dditionl reuse -e- Umum reuse Phse I -A-Umum reuse Phse I I 4 Figure 11 Computed spill losses from distributry nls for the (short term) extension nd reuse strtegies studied IT) E = E >, D <D *-> in S O 15 1D 35 9 B D Extension in Desert Cfeddn * B- No dditionl reuse -A-Umum reuse Phse I I -e-umum reuse Phse I Figure 12 Computed totl rop wter supply Western Nile Delt for the (short term) extension nd reuse strtegies studied V 16

21 It my lso be expeted tht s result of more tight wter supply sitution the spill losses from distributry nls my derese. This is onfirmed by the model omputtions (fig 11). More offiil reuse of dringe wter offsets this effet. /"I à? 2 m E 15 - ""* E D (!) U 1 5 / y / ' ^ ^ ^ / -~~~ 1> 1 1 x: o i C Extension griulturl lnd C? Z5 --No dditionl reuse -e-umum Phse I -A-Umum Phse I I Figure 13 Computed reltive totl rop wter supply Western Nile Delt in reltion to the reltive inrese of griulturl lnd for the (short term) extension nd reuse strtegies studied The result of ll these positive nd negtive hnges in individul wter blne omponents is given by the simulted rop wter supply for the omplete Western Nile Delt (fig 12).For ll strtegies studied, the totl rop wter supply inreses. When exmining the reltive hnge in rop wter supply in reltion to the reltive inrese of griulturl lnd (fig 13) it my be notied tht the rop wter supply inreses less thn the inrese in griulturl lnd, lso with the Umum reuse projets phse I or phse I & II.The only exeption is strtegy ode (165,1) when the inrese in griulturl lnd is 165, feddns nd ll dringe wter up to Trug pump sttion (Umum projet phse I & II) is reused (fig 14). Crop wter supplies omputed by the modelmost probbly still give too optimisti viewof the sitution due to the omputed dereses in muniipl wter supply (fig 9). Assuming tht the wtermngers willtke preventive mesures toseure drinking wter requirements, rop wter supply will tully be lower thn the ones omputed by the model. Bsed on the omputed wter blne omponents, theperformne of the different sub-systems n bedefined. Considering themin irrigtion onveyne system, the input tothis system onsists of the Nile wter supply nd theoffiil reuse of dringe wter. The trgeted output of the min irrigtion onveyne system is delivery ofirrigtion wterto the Irrigtion Distrits (represented in themodelby lultion units) nd the muniipl wter supply. 17

22 r~i ^ _/ C i " " CD 4- \m E X u ui u <D ) C 1 n o B -B -1Q I -12 C. é^ " \^ - ^ \ ^ _-. ^V,^ - ^^\<-, ^^\ ^^\ - ^\^ ^\ I l I l Extension griulturl lnd C?Q -e-no dditionl reuse -e- Umum Phse 1 -&-Umum Phse 1 1 \*. 25 Figure 14 Computed reltive rop wter supply per feddn ultivted re in the Western Nile Delt in reltion to the reltive inrese of griulturl lnd for the (short term) extension nd reuse strtegies studied u E <) 4-1 1/1 >, m o +J 1 Ol 1 2D 3D Extension in Desert (.thousnds of feddns} i-no dditionl reuse -e- Umum reuse Phse I Umum reuse Phse I I Figure 15 Computed min irrigtion onveyne nl system performne in the Western Nile Delt for the (short term) extension nd reuse strtegies studied V 18

23 The performne of the min onveyne system, defined by the rtio between the trgeted output nd the input to the system ppers to be quite high, bove 9% (fig 15). The inrese of griulturl lnds inreses this performne with nother full perent tillbove91 %. Additionl reuseofdringe wter through theumumprojet phse I nd phse I & II further inreses the min nl system performne, be it with only.1nd.2%. Thisis relly remrkble, beuse onewouldexpet higher opertionl losses upon inresing the totl inputs to the min nl system. Apprently,the inreseoftil-end losses ismore thn ompensted by lessthn verge inrese in seepge losses from the nl system due to higher dishrges. In the long term (fter 5 yers) the min system effiienies re more or less the sme (ompre tble 4 nd tble 5). 95 à? u 1 u ) u ^ ^ ^ ^ ^ ^ / ^ ^ ^ ^ ^ ^ ^ o 9 / ^ ^ ^ ^ ^ o 89 (-1 id Ol 88 B7 C 1D 2 3 Extension in Desert Cthousnds of feddns} 4 --No dditionl reuse -ô- Umum reuse Phse I -A-Umum reuse Phse I I Figure 16 Computed irrigtion distrit system performne in the Western Nile Delt for the (short term) extension nd reuse strtegies studied For the irrigtion distrit system, the input onsists of the delivery of irrigtion wter through themin irrigtion onveyne system,the ground wter use,nd the unoffiil reuse of dringe wter byfrmers. The trgeted output of the irrigtion distrit is delivery of irrigtion wterto the rops.bydefining the performne of the irrigtion distrit system s the rtio between this trgeted output nd input, prt of the on-frm systemisinluded in theirrigtion distrit system. Alsothe irrigtion distrit system performne defined in this wy ppers to be quite high, bove 88% (fig 16). The inrese of griulturl lnds inreses this performne with nother 6% till bove 93%. Additionl reuse of dringe wter through the Umum projet phse I nd phse I & II dereses the irrigtion distrit performnes with 1 respetively 2%. Apprently, on irrigtion distrit level, the inrese of spill losses due to higher wter vilbility by the Umum reuse projet is not ompletely ompensted by 19

24 lessthn verge inrese in seepge losses from the irrigtion distrit nl system. In the long term (fter 5 yers) the irrigtion distrit effiienies inrese slightly, depending on the implementtion of the Umum reuse projets (ompre tble 4 nd tble 5). Without dditionl reuse from Umum the vlue remins the sme, with Umum reuse projet phse I the irrigtion distrit effiienies inrese with bout.2%, nd with Umum projet phse I & II with bout.5%. Most probbly the reson for this dditionl inrese is the higher frmers' wter requirements to leh the dditionl slts reirulted into the system by the Umum reuse phse I nd/or phse I & II projets. u u n- 4- i s <D M Ul >, (ƒ) o i. o 1DD 2DD 3DD Extension in Desert Cthousnds of feddns} 3-No dditionl reuse Umum reuse Phse I!r-Umum reuse Phse I I Figure 17 Computed rop system performne in the Western Nile Delt for the (short term) extension nd reuse strtegies studied The input of the rop system onsists of the totl irrigtion supply to the field nd the trgeted output of the rop system is rop évpotrnspirtion. The performne ofthe rop systemis simply defined heres thertiobetween rop évpotrnspirtion nd totl rop wter supply. The rop system performne defined in this wy is little higher thn 65%in the referene simultion run (fig 17).Upon inresing the griulturl re the rop performne flls surprisingly with bout 4 nd 5% when extending the griulturl re with 165, nd 35, feddns respetively, to reh little bove 6% for the lrgest extension. The reson for this phenomenon must be the lekge losses in the newly relimed lnd whih hs been ssumed to onsistoforsetextured soils. Additionl reuseofdringe wterthrough theumum projet phse I inreses the rop system performne gin with bout 1 to 1.5%. Although the Umum reuse projet phse I & II inreses the totl vilble wter with n mount of 55 million m 3 dditionl to the 45 million extr m 3 of phse I only, the performne inrese of phse I & II is muh less thn tht of phse I, 2

25 only bout.5% (fig 17). Beuse the totl rop supply under the Umum phse I & II projet inreses proportionlly with the mounts of reuse (fig 12), the reson for the lower inrese in rop system performne of the Umum reuse projet phse I & IIompred to phse I only, is believed to be the higher slinity of the dringe wter of phse I & II. High irrigtion wter slinity myuses redutions in évpotrnspirtion due to inresed osmoti potentils in the soil. In the long term (fter 5 yers) the rop system performne dereses gin slightly with bout.6 to 1%. Thismybeused bythelongterm sliniztion effets ofredued wter supply nd inresed irrigtion wter slinity (ompre tble 4 nd tble 5). <u E ) *- (fl X (A ( > o D 1 2Q 3D Extension in Desert ([thousnds of feddns} -B-NO dditionl reuse -e-umum reuse Phse I -à-umum reuse Phse I I Figure 18 Computed overll system performne (short term) in the Western Nile Delt for the extension nd reuse strtegies studied Considering the ompletewestern Nile Delt nd Desert res, theonly input tothis system is the Nile wter supply. The ultimte trgeted output of this system onsists of muniipl wter supply nd rop évpotrnspirtion. The overll system performne hs been defined s the rtio of both. The overll performne for the referenesitution is littlebove 68% (fig 18). Extensionofthe griulturl re without inresing the reuse of dringe wter nd keeping the totl wter supply to the re onstnt, results in lower overll system performne. This mens negtive effet on the trgeted output nd should therefore not be reommended. With inresed reuseof dringewter theoverllperformne inreses bove thtof the referene sitution. Also with implementtion of the Umum reuse projets phse I or phse I & II, however,n inreseof griulturl lndof 35,gives lower performne ompred to n extension of 135, feddns. It n thus be onluded tht the seond extension of 185, feddns underthe onditions of onstnt wter supply of million m 3 nd the Umum reuse projet phse I nd/or phse I &II is not 21

26 reommended. The onlypossibly viblelterntive strtegies tothereferene sitution pperto be extension with 165, feddns ndumum reuseprojet phse I (165,5) nd extension with 165, feddns nd Umum reuse projet phse I & II (165,1). u CD E J in Ul > O D 1DD 2 3D Extension in Desert ^thousnds of feddns} No dditionl reuse C5y} -s-umum reuse Phse I C^Oy} Umum reuse Phse I I C5yD Figure 19 Computed long term (fter 5 yers) overll system performne for the different extension nd reuse strtegies studied for the Western Nile Delt Investments for lnd relmtion re not mde for the short term, but for the long term. For this reson the onlusion mentioned bove needs onfirmtion from the long term behviour of the system (fig 19). For the referene simultion run the systemperformne is slightly loweron thelongterm. Theretion of thesystem performne to lnd relmtion nd the Umum reuse projet phse I nd phse I & II is similr sfor the short term. For rel projet seletion between thetwo vible projet lterntives n eonomi nlysis is required. This is beyond the sope of the present study. 4.3 Soil nd wter slinity Thedifferent distinguished strtegies hvedefinite effets onsoilnd wter slinities. The inrese of griulturl lnd with 1% (165, feddns) leds to n inrese oftheverge slinity of pplied irrigtion wterof 3% for the short term simultion run nd 4%for the long term run (tble 6). The dditionl extension of nother 11% leds to n dditionl inrese of bout 4% on the short nd long term. Higher inreses of pplied irrigtion wter result from the Umum reuse phse I or phse I 22

27 & II projet. The highest irrigtion slinity inrese is observed when implementing Umum reuse projet phse I & II nd with n extension of 35, feddns in the desert. Under these irumstnes the irrigtion wter slinity hnges from 333 g.m 3 till 451 g.m" 3 (tble 6), n inrese of bout 35%. After period of 5 yers this inrese beomes bout 4% (tble 6 nd fig 2). Tble 6 Computed short nd long term verge slinity of some rop wter blne omponents for the Western Nile Delt for the Umum reuse projet lterntives with two options f or extension of the griulturl re in the Western desert. Slinity figures re given in g.m' 3 strtegy ode 1 Nile wter slinity rop irrigtion slinity Unoffiil reuse slinity Crop dringe slinity ekge slinity Dringe to se slinity Short term slinities (,) (165,) (165,5) (165,1) (35,) (35,5) (35,1) ong term (fter SO yers) slinities (,) 242 (165,) 242 (165,5) 242 (165,1) 242 (35,) 242 (35,5) 242 (35,1) ,74 1,136 1,125 1,116 1,22 1,198 1,193 1,91 1,19 1,169 1,151 1,277 1,263 1,254 1,815 1,84 1,799 1,82 1,811 1,89 1,815 1,827 1,878 1,863 1,868 1,945 1,931 1, ,692 1,775 1,89 1,782 1,853 1,9 1,89 1,77 1,842 1,866 1,836 1,979 2,15 1,99 '- the firstnumberin theoderefers to theextensioninthousndsoffeddns; theseondnumber refers to the dditionl reuseof dringe wter: 5indites phse Iof the Umumprojet; 1 indites phse I &II of the Umum projet. Keeping in mind tht not only irrigtion wter slinity inreses, but tht lso the totl rop wter supply per feddn dereses one would expet tht the dringe wter slinity would inrese more thn proportionl. The long term inrese in dringe wter slinity is muh less thn the 4% inrese in rop irrigtion wter slinity, however (fig 21). The mximum inrese is bout 6% only. The differenes between the reuse of dringe wter options on the hnge in rop dringe slinity re muh less thn the effet of inresing the griulturl re. Most probbly the inrese of rop dringe wter slinity is minly used by the effet of the redued rop wter supply. The question where the slts reirulted through reuse of dringe wter in the Umum reuse projet Phse I nd Phse II go still needs to be nswered. Exmining the lekge slinity (fig 22) nswers this question. The verge lekge slinity inreses with bout 3% when the Umum reuse projet phse I & II is implemented. 23

28 UI +J ( > 3 2D U 1 1 ö> (. u 1 C 5 1D Extension in Desert C^O -e-no dditionl reuse 6 Umum reuse Phse I -A-Umum reuse Phse I I Figure 2 Computed long term (fter 5 yers) hnge in rop irrigtion wter slinity in %for the different extension nd reuse strtegies studied for the Western Nile Delt 7 «+j Z 5 I in Ol r r 3 o 2 U (U > 1 o ( [ 5 1D Extens i on in Desert C%~) -B-no dditionl reuse - -o-umum reuse Phse I -lür-umum reuse Phse I I Figure 21 Computed long term (fter SO yers) hnge in rop dringe slinity in %for the different extension nd reuse strtegies studied for the Western Nile Delt 24

29 *u >> +J 1 (f) ) o> ID M 1 dl ) > C ( r o 3 2D 1D D 1 /, i i i C 5 1 Extens ion 15 n Desert C^Q B-no dditionl reuse -e Umum reuse Phse i -A-Umum reuse Phse 11 Figure 22 Computed long term (fter SO yers) hnge in lekge slinity in %for the different extension nd reuse strtegies studied for the Western Nile Delt g 25-2SC- = I I I I I I 1 1 I I I C S 5 Compostti dt (il ' ' I T * 15 rop*! 2 25 I I I 3! 35 i ' 4 i i 45 YEHRS 28> rifrtn» siritgy 29t (2.1 ne ohtont rus 3: <2C.5C< 'Jmntr. rtu» pii! 35: (2.5) Umum rust stti II Figure 23 Computed trend for SO yers in the verge soil slinity (mmho.m') in the Western Nile Delt for the strtegies with extension of 165, feddns in the Western desert 25

30 The mjority of lekge tkes ple in the new Desert res, this is lso the ple where theumum dringe wter is being reused.in these Desert res with ssumed orse textured soils nd deep ground wter tble lmost no dringe is omputed. This onlusion onerning the fte of the reirulted slts through the Umum projet is further onfirmed by the verge development of the soil slinity (fig 23 & 24). After 5 yers the mximum inrese in soil slinity, for the senrio with the mximum extension nd Umum reuse projet phse I & II, the soil slinity inrese is only bout 11.5%. The lehing effiieny of the sndy soils in the desert, where the Umum dringe wter is used for irrigtion is muh higher thn tht of the ly soils in the old lnds. Comptit* bt» (ll rps) YERRS 28: Rtrn ttnug«32:!4.coclno dditionl rus* 33: CSOO.OOCKUmum pump i. ruipht* 34: f4q.cc)umuir. pump t. rutephie 2 Figure 24 Computed trend for SO yers in the verge soil slinity (mmho.m') in the Western Nile Delt for the strtegies with extension of35, feddns in the Western desert Notieble is lso the ontinuously inresing trend in soil slinity for ll strtegies studied, even fter 5 yers. Sine lso the referene simultion run exhibits this trend, it n be onluded tht the ssumed equilibrium onditions were not met for this sitution. Extension of griulturl lnd uses soil slinity to inrese fster, but fter 5 yers pproximtely similr verge vlues re rehed, exept when implementing the Umum reuse projet phse I & II (fig 23 nd 24). The onlusion tht reuse of dringe wter in thedesert re hs little of no onsequenes for griulture nd for dringe wter slinities hsto beregrded ritilly however. Inthe SIWAREmodel simultions the ground wter onditions hve been kept onstnt. In the long term, lso in the Desert re, rise in the ground wter 26

31 tble my be expeted. This my in relity ffet lekge losses nd my led to need for dringe infrstruture in these new res in the future. Suh onlusion depends lsoonthe orretness of ssumptions regrding thessumed sprinkler irrigtion effiieny of 75% nd the ssumed orse textured soils in these new res. 4.4 Drinking wter slinity The Alexndri region depends on two soures for drinking wter. The lrgest prt (bout 8%)of its muniipl wter requirements omesfrom themhmudey nl. This soure of drinking wter is not expeted to be ffeted by the Umum reuse projets or thelnd relmtion tivities in the Western Desert.TheSIWARE model simultions predit mximum verge inrese of drinking wter slinity of the Mhmudey nl soure of bout 1% (fig 25). This is for the sitution tht no dditionl reuse projets in the Umum drin will be implemented. The reson for this inreseis more effiient wter useintheold lndusedby extension of griulturl lnd in the desert. This results in n inresed slinity t the Edko Reuse pump sttion delivering wter to the Mhmudey nl. -IQ 2 3DD Extension griulturl lnd Cfeddns*1CÛ -e-no dditionl reuse -e-umum reuse Phse I -4-Umum reuse Phse I I Figure 25 Computed long term effet of extension of griulturl lnds in the desert nd the Umum reuse projet phse I or phse I & II on the drinking wter slinity for the ity of Alexndri from the Mhmudey nl In se of implementtion of the Umum reuse phse I projet, the slinity of the Mhmudey drinking wter soure still inreses slightly, but less. With the Umum reuse projet phse I & II, the slinity dereses for the first extension of 165, 27

32 feddns nd inreses ginwiththe seond extension. Thederese mybe explinedby looking tthe reltive vluesof extension (bout 1%) nd the inrese in totl wter supply due to this reuse projets, whih is lso bout 1%. The drinking wter supply pump sttions on the Nubrey nl re loted t Km 6 long the Nubrey nl (Mriut pump sttion) nd t Km 96 (Borg El Arb pump sttion, tking wter from Mriut side brnh). The verge wter slinity of these sttions will inrese with bout 4% (fig 26)when Umum reuse projet phse I & II projets re implemented. 9 e B5 f * ) BOO 1 s o> 75 / 7 " j 55 C -1 i i Extension griulturl lnd Cfeddns*1CO --No dditionl reuse -A-Umum reuse Phse 11 --Umum reuse Phse I Figure 26 Computed long term effets of extension of griulturl lnds in the desert nd the Umum reuse projet phse I nphse I & II on the drinking wter slinity for the ity of Alexndri from the Nubrey nl It my be notied from the simultions presented in figure 27 tht the omputed slinity t Km 96, where Borg El Arb hs its intke, for the referene sitution is bout 6 g.m 3. Mesurements indite vlues up to 1,2 g.m" 3 for this lotion. Most probbly seepgeof slineground wter to the Nubrey nl initslst rehes hs not been properly librted in the SIWARE model nlysis. The inrese of omputed slinity of 4% for both drinking wter pump sttions tking wter from Nubrey nl would result in drinking wter slinities of up to 1,7 g.m" 3, whih is fr bove the epted mximum norm of 1,2 g.m" 3. This problem n bevoided by shifting their intkes for both drinking wter plnts with 15 nd 5 km respetively upstrem Nubrey nl to Km 45 before the mixing with Umum dringe wter will tke ple (fig 27). 28

33 E 8 6D - t / ( : h r w 4 _ : 2D i i ' f -ID 2D 3 4 5D 6Q 7 8 Distne CkrrO from intke Nubrey Cnl ' i i i utnlon 1B5,C Figure 2 7 Computed slinity profiles long Nubrey nl for the extension of griulturl lnd in the Desert with 165, feddns nd the three options for reuse of dringe wterfront the Umum drin 29

34 5 SEECTION OF PROJECT ATERNATIVES Both the extension of griulturl lnd in the desert nd the Umum reuse projet phse I or phse I & II re lrge projets requiring dditionl infrstruture to be onstruted, operted ndmintined. Deisionsregrding suhlrge projets should be bsed on omplete nlysis of benefits nd osts of the different lterntives. In this respet not only eonomi benefits nd osts ply role, but lso soio-eonomi spets hve to be tken into ount. Without being exhustive, benefits of these projets suh s the following n be mentioned: 1) rop prodution in the relimed desert re hve to be onsidered, but lso 2) the employment generted by job opportunities for new frmers in these res is n importnt issue. The osts to be onsidered in suh n nlysis inludes mongst others: 1) the loss of rop prodution in the existing griulturl res ('old lnds'); 2) the investment osts for lnd relmtion; 3) the investment osts for reuse of dringe wter infrstruture; 4) the investments required to seure the drinking wter supply in quntity s well s in qulity; nd 5) the opertionl ost of pumping the dringe wter from the delt re to the desert re. Afull-fledged nlysis s indited bove,be iteonomi or soio-eonomi, is beyond the sope of the present study nd no ttempt to do suh n nlysis will be mdein this report. The strtegies onsidering theextension inthedesert nd inresed reuse of dringe wter through the Umum reuse projets, simulted with the SIWARE model pkge, do provide n indition of hnges in rop prodution, however. This hnge in rop prodution is one of the most importnt soures of informtion on whih deisions regrding lnd relmtion nd reuse of dringe wter should be bsed.in this hpter theusefulness of omprehensive wtermngement simultion model s tool to ssist in estimting the benefits of suh projets will be demonstrted. Simultion of rop yields s suh hs not been implemented in the SIWARE model pkge. Reltive rop évpotrnspirtion, however, hs been shown to be, within ertin limits, linerly relted to totl dry mtter prodution (Abdel Gwd et l, 199). When exmining hnges in évpotrnspirtion distintion hs to be mde between the desert re, with sndy soils nd desert type of limte, nd the delt re with hevy ly soils nd more moderte miro-limte. Most probbly the produtivity of griulture in the old lnd, expressed per m 3 of évpotrnspirtion, ismuhhigher thn in the desertenvironment. Alsogriulturl mngement in these new lnds is different nd most probbly more ostly per unit of produt. For this reson the hnges in évpotrnspirtionin theold ndin thenew lnds re nlyzed seprtely. Extension of griulturl lnd in thewestern desertrequires lrge investments. Also the Umum reuse projet phse Ind phse I & II require investments nd opertion nd mintenne ost. The irrigtion wter for the new lnds hs tobe lifted by irrigtion pump sttions requiring dditionl expenses. The dringe wter from the Umum drin hs to be lifted first to the Nubrey nl through reuse lifting pump sttions, fter whih it will be lifted from the Nubrey nl to the newly to be 31

35 relimed res. The nlysis given hereis restrited to the gins in évpotrnspirtion in the desert re nd losses in the delt re of the lterntives studied (tble 7). Tble 7 Computed long term (fter 5 yers) évpotrnspirtion in the old lnds nd new lnds s result of the different extension nd reuse strtegies studied. Evpotrnspirtion gins nd losses in million m 3.yef' strtegy ode' Evpotrnspirtion Delt re Evpotrnspirtion desert re Totl évpotrnspirtion (,) (165,) (165,5) (165,1) (35,) (35,5) (35,1) 4,174 4,1 4,58 4,133 3,835 3,877 3,942 1,537 1,714 1,753 1,789 1,863 1,92 1,961 5,712 5,724 5,811 5,922 5,698 5,797 5,93 '- the first number in the ode refers to the extension in thousnds of feddns; the seond number refers to the dditionl reuse of dringe wter: 5 indites phse I of the Umum projet; 1 indites phse I & II of the Umum projet. Forthe gins nd lossesin évpotrnspirtion (tble7) distintion is mde between the Western Delt estof Nubrey nl nd the desert re westof Nubrey nl. Sine investments re mde for the long term, the long term (fter 5 yers) évpotrnspirtion hve been used in the nlysis. Two questions relted to profitbility of the projets n be put forwrd: 1)re the extensions of griulturl lnds under the onditions studied good deision? nd 2) re the Umum reuse projet lterntives under the onditions studied good deisions? With these onditions mentioned bove, the onstnt Nile wter supply of million m 3.yer ' nd the ssumed onstnt ropping pttern re ment. For ll situtions with relmtion in the desert the évpotrnspirtion in the desert inreses (fig 28). Exmining the slope of the reltions given in figure 28,it n be notied tht the inrese in évpotrnspirtion per feddn relimed re is less for the seond extension of 185, feddns, ompred to thefirst extension of 165, feddns. Both Umum reuse projets (phse Is well s phse I & II) hve positive effet on the inrese of évpotrnspirtion. This positive effet in thedesert re (inreseof évpotrnspirtion)is ompensted to lrge extent by derese of évpotrnspirtion in the delt re (fig 29). For the sitution without dditionl reusethis deresein the delt is moreor less similr to the inrese in the desert (fig 28 & 29). For the strtegies with the Umum reuse projets phse I nd phse I & II, the positive effets in the desert outnumber the negtive effets inthe delt. Compring the dditionl effet of Umum reuse projet phse I & II to tht of phse I only, itn be notied tht the inrese of évpotrnspirtion in the desert of phse I & II is less thn tht of phse I. In the delt the effet of phse I & II is more thn thtof phse I, however (fig 28 & 29). The reson 32

36 is the inresed irrigtion wter slinity, whih minly ffets the desert re where the dringe wter is being reused. <D U) <U ( m 1 o ( > ) > ID Q -1D 2DD 3DD Extension Cfeddns A 15 -No dditionl reuse -- Umum reuse phse I Umum reuse phse I & I I Figure 28 Computed hnge (long term) in évpotrnspirtion in the desert re s result of lnd relmtion for three lterntives of reuse of dringe wter E to -1 ) III in id O in > i o> ( z. u 1 2QD 3 Extension Cfeddns * "13' No dditionl reuse -$- Umum reuse phse Umum reuse phse I & II Figure 29 Computed hnge (long term) in évpotrnspirtion in the delt re s result of lnd relmtion in the desert for three lterntives of reuse of dringe wter 33

37 The totleffets of the strtegies on omputed évpotrnspirtion regivenin figure 3. The nlysis shows tht lnd relmtion in the desert with 165, feddns without dditionl reuseof dringe wter hsonly mrginl effet on totl évpotrnspirtion ndtherefore on totlrop prodution. The seond extension of 185, feddns even hs negtive effet nd should therefore not be reommended (fig 3). ( Q. U) 1 o ( > ) > 1 n u No dditionl reuse Umum reuse phse I & I i 1 ZDD 3 Extension Cfeddns * 1 -e-umum reuse phse I Figure 3 Computed hnge in (long term) évpotrnspirtion Western Nile delt s result of lnd relmtion for three lterntives of reuse of dringe wter Both Umum reuse projets, phse I s well s phse I & II hve positive effet on the omputed évpotrnspirtion. On the ondition tht the osts of these reuse projets re blned by the relted inrese in rop prodution nd other soio-eonomi benefits, the dditionl reuse of dringe wter (both phse I & phse I &II) should therefore be reommended s supplementl mesures to ugment the wter supply for the lnd relmtion of 165, feddns in the desert. Also under the onditions of dditionl wter vilbility of the Umum reuse projet, the seond extension of 185, feddns results in lower totl évpotrnspirtion (fig 3) nd therefore in lower totl rop prodution. The seond extension of 185, feddns should therefore not be reommended. Exmining the retion of totl rop évpotrnspirtion under the reuse of dringe wter onditions (fig 3) to the lnd relmtion options, shrp inrese n be notied for the first extension of 165, feddns, nd very smll derese for the seond extension with 185, feddns. The optimum point of lnd relmtion is loted where the inrementl osts equl the inrementl benefits. Most probbly the optimum is loted somewhere between the lterntives studied. In order to find 34

38 the tehnil optimum number of dditionl strtegies with lnd relmtion inthe desert should be simulted with the SIWARE pkge. Thenlysis presented here shouldbe omplemented byn eonomind soio-eonomi nlysis in order to provide suffiient informtion to deision mkers. Additionl informtion isrequired on profitbility ofgriulture in the desert s ompred to the delt re. Additionl informtion is required on the ost of the dditionl infrstruture nd opertion nd mintenne ost. Informtion is required on the vlue of dditionl employment opportunities in the newly to be relimed desert re. 35

39 5 CONCUSIONS In order to demonstrte the usefulness of the SIWAREmodel pkge s deision support system, two lterntives for extension of griulturl lnd in the Western Desert hve been exmined. The first extension studied ws bout 1% (165, feddns) ndthe seondextension 11.5% (185, feddns), bringing the totl extension to 21.5% (35, feddns). For ll these strtegies the totl Nile wter supply hs been kept onstnt resulting in redued wter supply per unit re of 9% for the first extension nd 18%for the totl extension. In order to ompenste for this redution inwter supply per unit re, reuseof dringe wterfrom the Umum drin hs been onsidered in two phses. Implementing phse Iof theumum reuse projet results in n inrese of wter supply of bout 4%.Phse I & II of the Umum reuse projet results in n dditionl wter vilbility of bout 4.5%, bringing the totl gins of wter to bout 8.5%. The resulting totl wter supply redution for thedifferent strtegies is given in tble 8. Tble 8 Computed wter supply redution (Nile wter & reuse of dringe wter) per unit of re for the different strtegies studied (%). extension griulturl re (feddns) reuse of dringe wter no dditionl reuse option Umum projet phse I Umum projet phse I & II ode redution ode redution ode redution 165, 35, (,)' (165,) (35,) (165,5) 5. (35,5) 14. (165,1).5 (35,1) 9.5 '- the first numberintheodereferstotheextensioninthousndsoffeddns;theseondnumberrefers tothedditionlreuseofdringewter:5inditesphse IoftheUmumprojet; 1indites phse I &IIoftheUmumprojet. Extension of griulturl lnd in the Western desert results in only smll inreses in totl rop évpotrnspirtion nd in lrge inreses in losses to the ground wter. The resulting simulted lrge dereses in dringe wter losses to the se n therefore not only be ttributed to n improvement of system performne. About 6% of the redution in dringe wter dishrge to the se is explined by n inrese of losses to the ground wter system. These results should be interpreted refully, beuse they re bsed on model simultions. The extension of new re hs been ssumed to tke ple on orse textured soils nd n on-frm irrigtion effiieny of 75% for sprinkler rops hs been ssumed. Moreover, on the long term it n be expeted tht ground wter levels will rise, thereby reduing lekge losses. In the model onstnt piezometri pressures hve been ssumed. As resultofthe tightened wter supply sitution in the strtegies studied,the model omputtions indite tht the muniipl wter supply will be redued. It should be kept in mind tht the mjority of drinking wter pump sttions re loted ner the 37

40 til-end of the Mhmudey ndnubrey nls.suh redutions in muniipl wter supply re not eptble, of ourse. In this respet the model simultions should beregrded s wrning tht speil mesures sfegurding the drinking wter supply re wrrnted when strtegies suh s those studied here re onsidered. The SIWARE model simultions indite tht unoffiil reuse of dringe wter by frmers inreses when thegriulturl lnd inthewestern desert is inresed, keeping thenilewter supply onstnt. Upon implementtion of theumum reuse projet phse I or phse I & II, the omputed unoffiil reuse of dringe wter dereses drstilly. Frmers loted ner the til ends of irrigtion nls nd lose to the Umum min drin pprently hve no longer ess to the dringe wter from the Umum drin. These frmers suffer not only from redued irrigtion wter supply, but re lso deprived of the dringe wter soure with whih they were used to ugment the irrigtion wter supply in se of shortges. The min irrigtion nl system performne, defined s the rtio between supply (Nilewterndoffiil reuseof dringe wter)ndtrgeted output (muniipl wter supply nd Irrigtion Distrit wter supply), whih is lredy quite high in the referene strtegy (bove 9%) inreses with full perent when dditionl lnd in the Western desert is tken into ultivtion. The Umumreuseof dringe wter projets phse I nd phse I & II result in minor further inreses in the min system performne. The irrigtiondistrit system performne, defined s the rtiobetween supply (irrigtion wter supply, ground wter use nd unoffiil reuse of dringe wter) nd trgeted output (rop wter supply), whih is lso lredy quite high in the referene sitution (bove 88%) inreses with bout 6% when dditionl lnd in the Western desert is tken into ultivtion. The Umum reuse of dringe wter projets phse I nd phse I & II result in derese of bout 2% in the irrigtion distrit system performne. The rop system performne, defined s the rtio between rop wter supply nd trgeted output (rop évpotrnspirtion),hngesin ompletely different wy. The rop system performne whih isbout 65% in thereferene sitution redues with bout 5% when dditionl lnd in the Western desert istken into ultivtion. Additionl reuse of dringe wter through the Umum reuse of dringe wter projets phse Ind phse I & II result in inreses of bout 1.5% inrop system performne. On the long term the rop system performnes redue gin with perentge of bout 1%. This my be ttributed to inresed soil slinity. The resulting overll system performne, defined s the rtio between Nile wter supply nd trgeted output (muniipl wter supply nd rop évpotrnspirtion), is positively influened by the inreses in the min irrigtion nl system performne nd irrigtion distrit system performne nd negtively by the derese in rop system performne. Theresultof theseopposite hnges is deresein overll system performne with bout 1% when dditionl lnd in the Western desert is tken into ultivtion. Additionl reuse of dringe wter through the Umum reuse of dringe wter projets phse I nd phse I & II results in n inrese of bout 38

41 3%. This results in n inrese of bout 2% for the ombined effet of expnsion in the desert nd inresed reuse of dringe wter. Judging on the overll system performne, extension of griulturl lnds in the Western desert without dditionl reuseofdringe wterthrough theumum projet ppers to be not good deision. Implementtion of the Umum reuse projet phse I leds to n verge inrese in irrigtion wter slinity of 15%. Phse I & II results in n dditionl inrese of irrigtion wter slinity of bout 2%, bringing the totl inrese to 35%. On the long term the irrigtion wter slinity isinresed with nother 3% for Umum phse I projet nd 7% for Umum phse I &II projet, bringing the totl inrese to 42%. The resulting long term verge irrigtion wter slinity of 475 g.m" 3 is expeted to provide only limited rop yield redutions for the mize nd vegetble rops when grown on soils with limited internl dringe onditions. Sine the higher irrigtion wter slinities re used in the Western desert, where internl dringe onditions re good, nomjor problems re expeted however,slongstheground wter tble in these desert res remins fr below lnd surfe. In ll strtegies studied ontinuously inresing trend in soil slinity is notied in the omputtion results, evenfter 5 yers. Sinelso the referene strtegy exhibits this trend, it n be onluded tht the ssumed equilibrium onditions for the referene sitution were not met. Extension of griulturl lnd uses soil slinity to inresefster, butfter 5 yers pproximtely similrverge vluesfor soil slinity re rehed, exept for the Umum reuse phse I & II projet. It n thus be onluded tht reuse of dringe wter in the desert re hs only limited onsequenes for griulture nd for dringe wter slinity. Thisonlusion hs tobe regrdedritilly however.inthesiware model simultions the ground wter onditions hve been kept onstnt. In the long term, lso in the desert re, rise in the ground wter tble my be expeted. This my in relityffet lekge lossesndmyledto seondry sliniztion in thesenew res in the future. Suh onlusion depends lso on the orretness of ssumptions regrding the ssumed sprinkler irrigtion effiieny of 75% nd the ssumed orse textured soils in these new res. Without dditionl reuse of dringe wter, relmtion of 165, feddns in the desert is most probbly not profitble under the ssumed irumstnes of onstnt Nile wter supply nd is therefore not reommended. On the ondition tht the osts the Umum reuse projets phse I nd phse I & II re blned by the relted inrese in rop prodution nd other soio-eonomi benefits, dditionl reuse of dringe wter should bereommended s supplementl mesures to ugment the wter supply for the lnd relmtion of 165, feddns in the desert. Alsounderthe onditions of dditionl wtervilbility of the Umum reuse projet, the seond extension of 185, feddns results in lower totl évpotrnspirtion nd therefore in lower totl rop prodution. The seond extension of 185, feddns should therefore not be reommended. 39