'C4 41,5 Depar t ment of t he Environment for Nor t her n Ireland STUDY OF WATER DEMAND AND SUPPLY IN NORTHERN IRELAND
Volume 1 Mai n Repor t A R C H / v e August 1984
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SIR ALEXANDER GIBB & PARTNERS in association with DELOITTE, HASKINS & SELLS MANAGEMENT CONSULTANTS M I OM S I M IND O M a N M • NO UNI M M INI M M I III I Dep a r t ment of t he Envir on men t for Nor t her n Ir ela n d STUDY OF WATER DEMAND AND SUPPLY IN NORTHERN IRELAND
Vol u m e 1 Ma i n Rep or t August 1984
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BELFA T
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SIR ALEXANDER GIBB & PARTNERS in a ssociat ion wit h DELOITTE, HASKINS & SELLS MANAGEMENT CONSULTANTS S IR A L EXA ND ER G IB B & PA RT N ERS I C O N S U L T IN G C N O I N E C R S Deloitte Haskins I-Sells "Ctgrnzit EA R LEY H O U S E 4 2 7 LO N D O N R OA D EA R L EY P 0 Box 20 7 R EA D I N G RG6 IB L 12 8 Queen Virloria Street.
• Et.( • n o me • E• 131,40 M o e , (l o LIN E S) London EC4P • t Le tl e n sli CIIIM O S O PRO• O C• O IN G Telephone 01 -248 3 9 13 8 4 0 0 6 1 Tein 8878 80
Re f . 48a/8 3450A
Augu st 1984
Th e Dep artme nt of the Env ironm ent for Nor thern Ireland , Northern Ireland Water Serv ice , Stormont , Belfast , BT 4 355 .
Dear Sirs ,
STUDY OF WATER DEMAND AND SUP PLY IN NORTHERN IRELAND
Following comple tion o f our work on th is study we have pleasure in presen ting our repo rt . Dra fts of th is repo rt have been discu ssed w ith your staff and accoun t ha s been taken of the comments raised at these d iscuss ions .
The repo rt is in two volumes .
Volume 1 Main Repo rt
Vo lume 2 Supporting 'Stud ies
Vo lume 1 dommen ce s w ith a sta tement o f our conc lu sions an d recommendation s and presen ts a sum mary o f the co ntents of the report .
W e wou ld like to re cord ou r apprecia tion o f the co -opera tion and va luab le as sistan ce which we have received dur ing the course o f the study from members o f Sta ff of the Dep artmen t o f the Enviro nm ent and o f the Dep artm en t o f Finan ce and Personne l .
Yours faithfu lly , for SIR ALEXANDE R GIBB & PARTNERS and DELO IST E HASK INS + SELLS IfeA D EPA RT M EN T OF THE ENV IRONM ENT FOR NORT HERN IRELAN D
ST UDY OF W AT ER DEMAND A ND SU PPLY IN N ORT HE RN IRELA N D
V OLUM E 1
MA IN REPO RT
TABLE OF CO NTENT S
PAGE N O .
CONC LU S IONS A ND REC OMM ENDAT IONS
SUMMA RY (iii )
C HA PT ER 1 INT RODUCT ION
1.1 Back grou nd
1.2 Terms of Re feren ce
1.3 Scope of Report 2
1.4 F ramew ork 3
1.5 Acknow le dgem ents 4
1 .6 Abb rev iat ions 4
C HA PT E R 2 OUTPUT S FROM WAT ER SO URCES
2 .1 In troduct ion 5
2 .2 Yie ld s of Source s 5
2 .2 .1 App ro ach 5
2 .2 .2 Yie lds fr om Re servo irs 5
2 .2 .3 Riv er Abst ract ions 6
2 .2 .4 Lo u gh N ea gh 6
2 .2 .5 G ro u ndw ater 7
2 .3 Ava i lab le Produ ct io n Cap acitie s of So urces 7
2 .4 Wate r Pro duc t /on 10
2 .4 .1 An nua l Ave rage P ro duct io n 10
2 .4 .2 Se a sona l Variat io ns 12 PAGE NO .
C HA PTER 3 WATER CONSUMPT ION 13
3.1 Base Year Consumption 13
3.1.1 Introduct ion 13
3 .1.2 Dom estic Consumption 13
3.1.3 Non-Domest ic Consumption 20
3.1.4 Overa ll Co nsumption Est imate s 22 3.2 Domest ic Consumption Fo recasts 24
3.2 .1 Genera l 24
3 .2.2 Imp act of Populat ion G row th 24
3 .2.3 Impa ct of Imp roving Liv ing Standards 26
3.2 .4 Impact of Fa lling Househo ld Size 30 3 .2.5 Forecasts 33 3.3 Non-Domestic Consumption Forecasts 33
3.3 .1 Ge nera l 33 3.3.2 Agricu lture 33
3 .3.3 Industrial Con sumpt ion 34
3.3.4 Commerce 35 3 .3.5 Construc tion 35 3 .3.6 Other (Public Serv ices ) 35
3 .3 .7 Agricu ltura l Domestic U sage 35
3.3 .8 Op erat ional Usage 35
3 .3 .9 Ad justment for Un der-registration of Me ters 36 3.4 Ove rall Consumption Fo reca sts 36
3.4 .1 Comments 37 3.5 Elast icity o f Demand 37
CHAPTER 4 UNAC COUNTED FOR WATER 38
4 .1 Ge ne ral 38
4 .2 Le akage in Sup ply Systems 38
4 .3 Water Balances 39 4 .4 Night Flow s in Be lfast 40
4 .5 Fu ture Levels o f UFW 43 PAGE NO .
CHAPT ER 5 REDUCT ION OF LEAKAGE 44
5 .1 Introduction 44
5.2 Leakage Levels 45
5 .3 Co sts of Leaka ge 47 5.3 .1 Method 47
5.3 .2 Un it Op erating Cost 47 5.3.3 Unit Cap ital Co st 47 5 .3.4 Annual Costs of Leakage 49 5 .4 Co st of Leakage Control 49
5.5 Co st of Repa irs 5 1 5.6 Annual Bene fits 52
5.7 Practical Aspe cts 52 5.8 Resources fo r Leakage Contro l 53
5 .9 Recommen dations 55
CHAP TER 6 PLANN ING CRITER IA FOR WATER SUPPL Y 56
6 .1 Introdu ction 56
6 .2 T reated Water Requirem en ts 56 6 .3 Output from Sou rces 57
6 .3.1 Proce ss Water 57
6 .3.2 Compe nsat ion Wa ter 57 6 .3.3 Ope rating Margins 57 6 .4 Leve l of Service to Consume rs 59
6 .5 Leakage Control 60 6 .6 Development Programmes 6 1 PAGE NO .
C HAPTER 7 AP PRAISAL OF PRO JECTS 64
7 .1 Int roduction 64
7 .2 Eastern Divis ion 66
7 .2 .1 Alternat ive Schem es 66 7 .2.2 Capital Co sts of Schem es 69
7 .2.3 Operating Co sts 70
7 .2.4 Mou rne Condu it 71
7 .2 .5 Lough Island Reavy 72
7 .2 .6 _Comp arison of Schemes 74
7 .2.7 Bangor Re se rvoirs 78 7 .3 Ba llymena/An trim/La rne 79
7 .4 Co lera ine/Ballymone y/Mo yle 8 1
7 .5 Southern Div ision .83
7 .6 S trabane/Oma gh 85 7 .7 Ferma nagh 86
CHAPTER 8 DEVELO PMENT PLAN S 87
8 .1 Introduction 87
8 .1.1 Lead T ime 87 • 8 .1.2 Cu rrent Su rp lus Capac ity 88
8 .1.3 Itate of Growth of Demand 89
8 .1.4 Reduction of Le a ka ge 89 8 .2 Eastern Div is ion 89
8 .3 Ba llymena/Antrim/La rne 9 1 8 .4 Co leraine/Ba llym oney/Moyle 92
8 .5 Ma ghera felt/Cookstown 92 8 .6 Southern D iv ision 93
8 .7 Londonderry/Limavady 93 8 .8 Strabane/Oma gh 94
8 .9 Ferm anagh 94 8 .10 Priority Area for Leaka ge Reduction 95 PAGE NO .
C HA PT ER 9 INFO RMA T ION FOR MON ITO RING SUPPLY A ND DEMA ND 96
9 . 1 Intro du ct io n 96
9 .2 Man a geme nt Informa tio n Re qui re me nts 96
9 .3 Wa te r So u rces 97
9 .4 Wate r Consum p tion 98
9 .4 . 1 Unm ete red Consump t ion 99
9 .4 .2 M ete red Consump t ion 100
9 .4 .3 Use of Ex te rna l In form ation Source s 104 .
9 .5 Una cco unted for W ater/Le aka ge Cont ro l 105
9 .6 Compu ter Fac ilit ies 106
9 .7 Summa ry 107
A PP EN D IX 1 Current Cap ac it ie s of Sour ces 109
A PP ENDIX 2 Non -Enum e rated Popu lation 113
A PP END IX 3 Popu la t io n G row th 115
A PP ENDIX 4 W ater C on sump t ion 119
A PPEN D IX 5 Econom ic A ct iv ity Pro je ct io n s 125
A PP ENDIX 6 Ela st ic ity o f Dema nd 128
A PPEND IX 7 Un it Co s ts of Le aka ge 133 A PP ENDIX 8 Co st o f Leakage Control 138
A PP EN D IX 9 Co mpa rison of Cap ita l Costs fo r Ma jor Sch em es aroun d
Be lfast 143
A PP END IX 10 Effe cts of Po ss ib le Se quence s of De velopm ent fo r
Easte rn A rea schem es 144
A PPEN D IX 11 Abb reviat io ns 147 .LIST OF TABLE S
PAG E NO .
TAB LE 2 .1 G ro undw ater Prod uct ion in 1982
TABLE 2 2 Summa ry of Curre nt ly Avai la b le So ur ce s 8
TAB LE 2 .3 Annu al Ave ra ge W ate r Produ ct ion 11
TAB LE 3 . 1 Co vera ge of Metered District Exercise 15
T AB LE 3 .2 M etered D istrict E xe rcise - Summa ry of Re su lt s 18
TAB LE 3 .3 Base Yea r Domest ic Consump tio n and Popu la tio n
Estim ates by Su b -Div ision 2 1
TAB LE 3 4 Summa ry of Ba se Year (198 1 ) Co nsump tion Est ima tes 23
TABLE 3 .5 Po pu la tion P ro je ctio ns by Div ision 25
T AB LE 3.6 Ow nersh ip of Water U sin g App li ances/Am en ities 27
TAB LE 3 .7 Pro je ctions of Own ership o f W ater Usin g App lian ces/
Am enit ies 28
TAB LE 3.8 W ate r Use by Comp onents 29
TAB LE 3.9 Lmpact of Imp rov in g Liv in g Stan da rds 30
TAB LE 3 . 10 Dom estic W ater Consumption by Diffe re nt Hou seho ld Size 30
TAB LE 3 . 11 Chan ge s in Hou seho ld Size 3 1
TAB LE 3 . 12 Fo re cast Change in Ho useho ld Compo s it ion 32
T AB LE 3.13 Imp act of Chang ing Househo ld Size CoMpo s itio n on
Domest ic W ater C on sump tion 33
TAB LE 3 .14 Agricu ltu re - Overal l Con sumpt ion G rowt h Facto rs 34
TAB LE 3 .15 Summa ry W ate r C on sump tion Fo re casts 36
T AB LE 4 .1 Le ak a ge Rat es 4 1
TAB LE 4 .2 W ater Balan ces 42
TAB LE 5 . 1 Ne t Night Fl ow s 46
TAB LE 5 .2 Ann ua l Costs o f Lea ka ge 50
TAB LE 5 .3 Annual Co sts of Le aka ge Co ntro l 5 1
TAB LE 5 .4 Ann ual Be ne fits 54 PA GE NO .
T AB LE 7 .1 Costs and Y ields o f Po ss ib le New Ma jo r Sou rces 69
T AB LE 7 .2 Co sts an d Yield s o f I;ough Is land Reavy Expa nsio n 74
TAB LE 7 .3 Ra nk ing o f Eas te rn A rea Scheme s (as sumi ng real inc re iise
in co st of ele ct ricity ) 75
TABLE 7 .4 Rank in g o f Ea ste rn Ar ea Schem es (co n sta nt elec tr ic ity
co sts ) 77
TAB LE 7 .5 Co st of W ater from Inv e r Dam 80
TAB LE 8 .1 Su rp lu s Ca pa city in Sy stem A reas 88
TA BL E 9 .1 So c ia l and Eco nom ic Stat istica l Re q u irem en ts 108 L IST OF F IGU RE S
Fo llow in g Pa ge No
F IGU RE 1.1 Div is io nal and Sub -Div is io na l Areas
F IG URE 2 .1 Annua l Avera ge Water P rodu ct io n - Eastern
Div is ion
F IG URE 2 .2 Annual Avera ge Wat er Produ ct ion - N orth ern ,
Southe rn and Weste rn D iv is ions
F IGU RE 3 . 1 Tr end s of Househ old Own ersh ip of Wa te r-Us in g
App l ia nces in G reat Br itain 28
F IG U RE 3 .2 Ch an ge of Hou seho ld S ize in N orth ern Ire lan d 3 1
F IGU RE 6 .1 Produ ction Forecasts w ithou t Le ak ag e Redu ct ion -
Eastern D iv ision 56 F IGU RE 6 .2 Production Fo recasts w itho u t Lea kag e Redu ction -
Northe rn Div is io n 56 F IG U RE 6 .3 Product io n Fo recasts w itho u t Leakag e Reduction -
Sou th e rn D iv is ion .56 F IGU RE 6 .4 Prod u ct ion Fo recasts w ithou t Leak ag e Redu ction -
We ste rn D ivisio n 56 F IG U RE 6 .5 Po ss ib le Effects o f Lea kage Reduct ion P ro g rammes -
Eastern D iv isio n 6 1
F IGU RE 7 .1 Easte rn Div ision - Dev e lop m en t Op t ions 66
F IGU RE 7 .2 Co lera ine/Ba llym oney/Mo y le - De ve lopm ent Op t ion s 8 1
F IGU RE 7 .3 Southe rn Div is ion - De v e lop m en t Opt ions 8 3
F IGU RE 7 .4 Ferma nagh - Dev e lopm ent Op t ion s 86 CONCLUSIONS AND RECOMM ENDAT IONS
The m ain findings arising from th is study are as fo llows :-
The di ffe rences between yie lds of currently av ailab le sou rces of
water and cu rrent treated w ater p roduct ion a re low, and th is is a
cause for concern . In Easte rn Division these differences are less
than 5 % and in Northern and South ern Div isions they are less than 10% .
Reco rded wate r production between 1973 and 198 3 has been increasing
on a Div isio nal basis at between 2 .6% and 3.9% per annum .
Ident ified water consumpt ion is rising and the range of long run forecast annual in crease is between 0.7% and 2 .2% pe r annum .
Unaccounted for Water (UFW ) being the di ffere nce betw een product ion
and identified consumption, is a very high p roportion of p roduction . UFW includes identified leakage , un ide ntified leakage (includin g that
from trunk mains ) and unide ntified consumption .
With rising total dema nd , includ ing UFW , it is essential that leakage shou ld be reduced as, pa rt icula rly in th e Eastern Div ision , this is the on ly cou rse wh ich wil l meet increas ing needs of con sum ers over
the next few years . Deve lopm ent of ma jor new sources cou ld not be
comp leted in time to meet th ese needs .
It is clearly economica lly benefic ial to redu ce ident ified leakage in distribu tion systems to rea listic target leve ls and it is essentia l
that adequate resou rces should be made availab le as soon as po saib le fo r effe ct ive leaka ge reduction and contro l programmes .
Prep ara tions for in troducin g new source developments for the Ea ste rn
Ar ea should be initiated now but should take account of the po tential which ex ists for leakage reduction . These prep arations shou ld
include sou rce identificat ion , outline design and the documentation requ ired for public inqu iry .
(i) If the resources needed for effective leakage redu ction are not made
available , the de velopment of a neW ma jor source for th e Eastern Area is th e on ly possible cou rse if future dem and s are to be met . In
these circums ta nces it w ill be essential to proceed without delay to pu b lic inqu iry and the ensuin g stages of detaile d design and co nstruction .
Fina l decisions to comm it ma jor financial expe nd iture on new source
deve lopment cannot wa it on the resu lts of leakage reduction work for
more than two or three years and fai lure to make progress with the
ea rlier stages of promotion during that pe riod w ill leave no
opportunity for making up the lost time if leakage redu ct ion work proves to be less effective th an ant icipated . In that event it would be necessary to contemp late the introduction of w ater restrictions
ov er a susta ined pe riod until a new source had both been appr oved an d
constructed . Th e costs of promotional work prio r to construction w ill not be w asted whatever the ou tcome of the leakage reduct ion
p rogramme , although they mi ght be incurred ahead of the tim e when
they were actually req u ired .
10 . For the Ea ste rn Area , high pump ing costs mean that the Tu nny Point
Scheme is not the most favourable . The most attractive large schem es
for the Eastern Area are further developm ent of the Lou gh Neagh source at Cas to r Bay and a new upland sou rce at G lenwhirry, the
eco nomic differences bein g ma rgina l. Secondary factors tend to
favour. Castor Bay , but only if the p roblem of dealing w ith the
effects of alga l blooms in Lou gh Nea gh can be ov e rcome at reasonable co st .
Informat ion systems fo r p lann in g and operation ma na gement require
imp rovement , and it is essential that this should be addressed so
th at the ba lance of dema nd and supp ly can be kept under regu lar review . SUMMARY
SCO PE OF THE STUDY
The Study of Wate r Dema nd and Supp ly in Northe rn Ireland commenced in
Sep temb er 1983 and this Fina l Repo rt presents its con c lusions and
recomm en da tio ns . The ob jective of the study is to determine the wa ter
supp ly nee ds in Northern Ireland, p articu larly in the Eastern Area , to examine the data on wh ich water supp lies are planned and to su ggest
imp rovements w he re app rop riate . The stu dy invo lies the follow ing .
The asse ssment of the yie lds from availab le so u r c e s and the comparison of these yie lds w ith cu rrent water p roduction requ iremen ts .
Th e analysis of water consum ption requ irem ents both as to categories of utilization and loca tion of dema nd, and the p repa rat ion o f
pro jections of dem and to the year 2000 .
Ide nt ifica tion of lev els of u naccounted for water (UFW ), includin g leakage and ana lysis of the cost effectiveness of furth er U FW
reduc tion .
Assess ing the needs for ma jor new sources and development of criteria
for taking decisions for the developme nt of new sources .
Ma king recommendations for the main features for the ma nagem ent of the water supp ly/demand balance .
A review of the information needed for the monito ring of supp ly and demand .
Th e study has been carried ou t us ing water service sub- div isions as the basic geograp h ica l units . The base year for wat er consump tion ana lysis is taken a s 198 1, for wh ich the most recent census da ta are available . Co sts have been taken at mid- 1983 p rices .
The content s of the re p o r t are summa rized in the follow ing pa ges . OUT PUT FROM SOURCES
Conce rn rega rd ing the ab ility of cu rrently available sources to
meet rising demands fo r water has increased in recent years and is one of
the reasons for the present study . Thu s a primary step is to assess the
y ie lds from the available sources and to compare them with cu rrent and p ro jected water requ irements , as describe d be low .
Surface water is the most imp ortant source of water in Northern Ire lan d , althou gh groundwater is also used . For up land sou rces regiona l re lat ionsh ips have been deve loped between rese rvo ir storage vo lumes and yie lds , us ing ava ilab le hydro logical and meteo ro logica l data . These
re lat ionsh ips have be en used to establish y ields at frequencies of
rese rv oir failure of on ce in 20 years and once in 50 years for all existin g sou rces and likely new sources . Estimates have also been ma de for direct
river abstraction . Th ere is effective ly no hy drolog ical limitation on use of Lo ugh Nea gh for water supp ly . For groundwa ter , ope rating records are use d as the basis for capacities , although Water Serv ice assessments for the ult ima te outputs of the cu rrent borehole p ro jects have be en ado pted .
In asse ssing availab le yields 1 in 50 year failu re levels have bee n used and account has been taken of prescribed f lows , p rocess w ate r req uire- ments and system capacities as app ropriate . The total availab le yie lds are summa rized in the table be low for each Div is ion . The tab le also giv es the water produ ct ion leve ls for 1983 and the grow th rates of water p roduction over the past 10 yea rs . (Allow ance has been made for th e closure of the Co urtaulds facto ry in the growth figures for th e Eastern D ivision ).
OUTPUT FROM WATER SOU RCES
Div ision Cu rrent Sou rce Average Production Annual Compound G rowth Rates
Capacity 198 3 in Avera ge Production 1973-8 3
Ml/d Ml/d Overa ll Underlying
(1) Least squares ana lysis (iv) 1 These figure s illustrate the limi ted margins be tween cur rent source capac ities and production levels at Div isional leve l .
Seasonal prod uction pe aks have occurred p rincipally in the w inter , p robably due to bu rst ma ins . How ever, in mi lder years significant summ er
peaks are evident .
WATER C ONSUMPT ION
3 .1 Base Year Cons tion
Most dom estic premi ses are not metered and wa ter charges ax e 1 re covered through the domestic rates . Non-domestic con sumers are gene ra lly metered and charges are made on th e basis of wa ter consumed . Thus direct eviden ce of con sump tion is availab le for only non-dom estic con sumers .
For dom estic prem ises , water consumption estima tes hav e been derived
from the results of a d ist rict mete ring exe rcise carried out by the W ater
Se rvice . A tota l of 73 rep resentative districts generally of about 30
ho uses each were used , in which waste levels w ere low . New meters were
in sta lled and read ings take n in three sep arat e pe riods between Novembe r 1 198 3 and Ju ne 1984 . After ma king corrections for leg itimate night use and allow in g for the occupa ncy ratio of the districts surv eyed , an ave rage 1 daily consumption of 125 lit res p er head w as derived for use in this .study . Th is figure has been used to estima te total dom estic consumption for each
sub-div ision on the basis of the 198 1 census , co rrected for non -enum erated p opu lat ion .
For non-domest ic consumers estimat es were based on mete red data
p rovided from w ater ch argin g records . The data have been adjusted for non-
metered consumers and also for app a rent er rors in meter accur acy based on tests ca rried out by the Water Serv ice . The re sults are brok en down by
consum er category -and sub -district .
The estimated average con sump tion in . the base year for each Division is show n in the tab le in the next section .
(v)
I 3 .2. Consum tion Forecasts
Forecast s of domestic consumption to the year 2000 have been made on the basis of fo recast increases in popu lation , w ith adjustments for imp roved liv ing standards and falling household size . Popu lation increases have been based on cu rrent Governm ent p la nning projections . Livin g standard changes have b een assessed on the bas is of data on wate r using app liances , includ ing a survey of about 2500 households carried out during the course of this study . Grow th rates , derived from surv ey s in Great Britain , were used to obta in fac to rs for futu re trends in appliance ownership in Northern Ire land . Househo ld size change s have bee n based on recorded trends . To allow for uncertainty a range of grow th bands has be en used in each compo nent for pl a n n i n g purpo ses .
For no n - d o me s t i c consumption , forecas ts have be en based on p rojecte d ch anges in approp riate activity ind icators for five p rincipa l sectors, agriculture , industry , commerce , co nstruction and oth er (main ly public serv ices ).
An allowance of 3% o f total produ ct ion has bee n made for operational usa ge .
(vi) Overall base yea r and forecast consumptio n levels are as follows for ' each Division :-
Div is ion Base Yea r Forecast Consump tion in
Consump tion 1990 2000
Ml/d Ml/d Ml/d
The fo recasts rep rese nt annual increases of abo u t 2.2%, and 0 .7% fo r the high and low pro jections respective ly .
3.3 Elast icit of Consum tion
There is no firm evidence concerning the elast ic ity of water consumption w ith respect to p rice or income in Northe rn Irela nd . Ev iden ce from industrialized coun tries suggests that domestic dema nd is not
sensitive to changes in p rice but is affected by levels of in come . Research in En gland indicates that non-dom estic consump tion is affected by p rice and , to a g reater extent , by industrial ou tput . UNA CCOUNTED FOR WAT ER (UFW )
UFW comprises the difference between measu red wa ter production and identified consumpt ion . Its ch ief component is lea ka ge from the p ipe netwo rk . Figures for pro duction are availab le from Water Serv ice record s and estimates of base year consump tion a re re ferred to in Sect ion 3.
4 .1 Leaka e from Su 1 S stems
Minimum night flow data from either district m eters or waste water m eters have been used to asse ss leaka ge rates in dis tribu tion netw orks for a ll sub-divisions , with allowances being made for le gitimate night flows th rough trade m eters and domest ic households . In th e absence of firm evidence on ly app roximate est ima tes can been made fo r t r un k mains , based on the results of Water Research Centre (WRC ) studies .
4 .2 Wa ter Balances
Ideally the sum of estimated water consumption and measured leaka ge should equal w ater p roduction , but in p ractice this is not so . The difference , or balance , is an indication of the unce rtainty of estimates and measu rem ents as well as of undetected consumpt i on and leakage . The availab le informa tion results in the fo llow ing figures for each Divis ion for the base y ear.
Division Production Estima ted Identified Balance Consumption Leakage M l/d Ml/d Mald Ml /d
Eastern 307 167 109 + 32
No rthern 114 74 47 - 8 Sou thern 118 73 44 + 2 W este rn 107 60 50 - 4
Northe rn Ire land 646 374 250 + 22
It is evident that further work is needed to obtain better under- stand ing of the larger ba lances . 4 .3 Futu re Levels of UFW
Trends in water production over recent years ind icate that UFW has been rising a lon g w ith consumption . Thus it mu st be a ssumed that unless po sitive mea sures are taken to reduce UFW it will continue to rise . For lack of other information it has be en assum ed that in the absence of more
effective leaka ge control UFW w ill tend to rise at the same rate as ident ified con sump tion .
REDUCT ION OF LEAKAGE
With the limi ted manpow er availab le and w ith the assistance of consult ing engineers the Water Service has for some t ime endeavou red to
reduce leaka ge , bu t the results of this study show tha t UFW levels are higher than is desirab le . Thus a dete rmin ed e ffort involving considerable increases in manpow er , working to a prope rly prepared programme is needed to bring UFW to a more reasonable lev el than at p rese nt .
5 .1 Leakage Leve ls
Data from base year leakage estima tes su ggests that overall net
night flows per prope rty are in the range o f 20 to 40 litres pe r ho ur . These are high figure s and it should be po ss ib le to reduce them
significantly . Fo llowing the methods re comme nd ed in NWC Rep ort No . 26 , and making ad justm ent for cond it ion s in Northe rn Ire land , target leakage rates in the ran ge 13 to 22 litres per p rope rty per hour shou ld be achiev ed if active leaka ge contro l is extended using waste water me ters .
Levels of trunk ma in leakage should also be iden tified and reduced to accep table amounts .
5.2 Costs of Leakage
Savings aris ing from leakage reduction can be estimated on the basis of two components ,
- reduction in op erating costs - de ferment of cap ital expend itu re . Unit operating an d cap ital costs have been calcu lated for each of the p rincipal sup ply systems and the resulting total unit costs are in the
ran ge 3 .9 to 7 .7 pe nce per cub ic me ter . The larger figures arise in areas whe re pump ing costs are re latively high , such as from Dunore Po int
Trea tment Works into Be lfast . By app lyin g the se figures to the existing
and ta rget leakage levels the re levant annual values of potenti'al sav ing
have been est imated .
5.3 Cost of Leaka e Contro l
Effective leakage contro l requires that adequate financia l and manpow er resou rces are allocated to the work . The est imated to tal annual
cost of leaka ge contro l is £6 14 000 , requ iring a total of 68 indust rial and
supervis ing sta ff work ing on leaka ge det ection .
In add ition , resources are requ ired to rep air the arrears of leakage s as a resu lt of more intensive leakage contro l, over and above no rma l allocations for this wo rk . It is estimated that this would add a tota l of £ 315 000 per annum and a lso require some add it ional 25 staff du ring the first few yea rs . The annual equ ivalent cost amo rtized over 20 years amou nts to £ 88 000 per annum .
5 .4 An nual Benefits
Th e annua l bene fits that can accrue from leaka ge contro l for each
Div ision are as fo llows :
Div ision Net Sav ing Saving of Water
Ml/d
( x ) It is clea r that sign ificant bene fits can ar ise both econom ica lly and
in terms of water p roduction from effective leak age control. It is there fore recomm ended that the requ ired resource s of manpower and finance
shou ld be made ava ilab le so th at the necessary leakage programm es can be p lanned and executed . The effect iveness of this Work must o f cou rse be
closely monito red .
PLANN ING FO R WATER SUPPL Y
A numbe r of factors must be taken into acc ount in prepa ring
development plans for sources as d iscussed in th is section .
6 .1 Treated Wate r Re irem ent
Pro jections for treated wate r production have been prep ared , which include bo th ident if ied consumption and UFW . These in clude h igh , m id and
low est imates . It is assume d that UFW will grow at th e same rate as fo recast consump tion in the ab sence of effective leakage con tro l .
6 .2 Out ut from Sources
In assess ing the requ irem en ts for source cap acities a numbe r of factors must be allow ed for in add it ion to treat ed water production .
process wate r requ irement comp ensa tion water (i.e . p rescribed flow )
operating margins at critical po ints in tim e
The first two depe nd on local conditions . The p u rpose of the minimum op erating ma rgin is to allow for short term fluctuatio ns in dema nd , persistent clima tic variation and emergency situ ations . Evid ence from
Ea stern Division records show s tha t the maximum variat ion due to the closu re of Cou rtau lds facto ry resulted in a va riat ion from 6% above the genera l consumption trend to 6% below . Th is range is likely to be extreme .
It is conside red that an operat ing ma rgin of 5% of to tal prod uction (abo ut 10% of consumption ) shou ld be allowed in dete rm ining the tim ing of imp lem en tation of a new sou rce . However, in systems w hich are supp lied fro m small reservo irs the effect of summ er peak demands may require a greater ma rgin . 6 .3 Leve l of Service
Wh ile it is possib le to impose restric tions on consume rs it has been concluded that , as a basis of p lann ing , restrictions should not be imposed mo re frequ ently than once in twenty ye ars on avera ge . This assumes that such act ion wou ld effectively increase the yield from sou rces . How ever ana lysis of the Silent Valley system has shown tha t restrictio ns in output at this frequency would not increa se the effective y ield s ign ificantly above the 1 in 50 year failu re level . In view of this and the uncerta inty of the data it is considered that for p lanning purposes it wou ld be best to adop t the conventiona l prac tice of prov iding sources for wh ich significant reduction in sup p ly would not be expected more than once in fifty years .
6 .4 Leakage Co ntrol
Wh ile consum er dem and is expe cted to increase , the total level of water dema nd in the next few yea rs w ill depend largely on the success achieved in reduct ion of leakage . For planning purposes 'it is therefo re nece ssary to consider the op tions of :
a . no reduction in leakage b . the ach iev ement of target leakage lev els
The resu ltant leve ls of UFW shou ld be super impo sed on the range of consump tion forecasts that have be en described .
6 .5 Develo men t P ro ram m e S
It has been shown that leaka ge contro l , if successfu l , is highly cost effective . How ev er , even if extra sta ff are prov id ed to supp lem ent th e effo rts already be ing app lied to the supp ression of waste , it has to be reco gn ised that the defined ta rget levels ma y well not be achieved w ithin the short term . unfortunately the lead time need ed for the imp lem entation of a new so urce means that pro gre ss w ith the nece ssary promot ional work cannot be set aside to await the resu lts of a leakage reduction programme . It is of paramount imp ortance th ere fo re that prep aratory wo rk leading to the inquiry stage on new so u rc e deve lopmen t for the Easte rn Area should p roceed immediate ly so as to provide for the contingency that leakage will not be significantly reduced within two or three years . In the ev ent of a new source be ing requ ired at an early date the prepa ratory w ork which can be accomplished du ring that pe riod will be vital and , if that time is lost , sustained restr iction s on water demand may have to be contemp lated . If leakage reduct ion (and its continu ed supp ress ion ) is sufficient to delay th e promo tion of a new sou rce , the prelimina ry work w ill not hav e been wasted as a new sou rce w ill eventua lly be requ ired .
In the event that the resources nee ded fo r leakage redu ction and co ntro l are not forthcom in g , leakage wou ld continue to rise a long w ith consum ption , and would resu lt in more frequent restric tions in supp ly . In these c ircums tances it will be essential for a new so u rce to be dev elop ed for the Eastern Area withou t de lay .
APPRAISAL OF PROJECTS
A numb er of po ssib le schem es have been eva luated to meet future increases in p roduction req uirement s , although , in v iew of the unce rtainty re gard ing the effects of leakage reduction , the prec ise timin g of such pro jects mu st remain open . Pre ferred schemes have be en ident ified on econom ic grounds on the basis of di scounted unit costs of water but oth er factors such as environmenta l, socia l, legal and water quality aspe cts and land costs are not with in the scope of this repo rt . The conc lusion s of these considera tions are as fo llow s :
7 .1 Eastern Div is ion
Of the po ssib le ma jor schemes there are on ly ma rginal di fferen ces be tween an extension to Lough Nea gh abatraction at Ca stor Bay and the dev elopment of a new up land sour ce at Glenwh irry . Ta kin g account of secondary factors , inc luding land acqu isit ion and comp ensation water requ irements at G lenwh ir ry , indicates that the former wo uld be preferab le but only if the problems arising from algal blooms in Lough Neagh can be so lved at reasonab le cost .
The proposed Tun ny Point schem e is less economica l on account of the high p umping costs . The dev elopm ent of Lough Island Rea vy to yield a further 17 M l/d is attra ctiv e , but wou ld depe nd up on the imp lemen tation of a p rogramme of
renovat ion of the Mourne Conduit .
7 .2 Ba ll me na/Antrim/Larne
Construction of the Inver Dam an d asso ciated wo rks .
7 .3 Co lera ine/Ball ney/M o le
Interconnection of Altnah inch and Ba llin rees sou rces .
7 .4 South ern D ivision
Deve lopmen t of the Camlou gh Source .
7 .5 Stra bane/O ma gh
Inte rconne ction of Lough Fingrean with Riv er Derg has been considered but found not to be economi c .
7 .6 Fermana gh
Inte rconne ction of De rrylin Boreho le and Ki llyhev lin with Killyfole .
DEVELO PM ENT PLA NS
Outline plans have been made for each of the areas for wh ich source deve lopm ent will eventually be required . The po sition regarding ma rg ins be tween availab le sourc e capac ities and cu rren t demand is rev iewed ,
togeth er with the likely effects of leakage redu ction .
In all cases prio rity mu st be given to the redu ct ion of leak age but as the su ccess of th is work cannot be fo reca st it is not poss ib le for firm programm es to be made . However , prio rities for plannin g can be estab lished and the se a re as fo llow s :- 8 .1 Eastern Division
Small sca le improvements at Dunore Po int Treatm ent Works to in crease ou tput by about 5 M l/d .
Develop men t of the LoU gh Neagh sou rce at Castor Bay to yield
about 110 M l/d , p rovided that treatment p roblems can be re so lved at reasonab le cost .
8 .2 Ball mena/An trim/ La rne
Extension of pipeline from Dunore Point fur ther northwards to imp rove the supp ly to Ba llymena .
Develop ment of Inver Dam and associated works to provide an
extra 12 M l/d .
8 .3 Co leraine/Ballym on e /Mo le
Cu rrent sources should be adequate until the en d of the centu ry .
8 .4 Ma herafe lt/Cookstown
Sou rces app ea r to be adequa te for the foreseeab le futu re .
8 .5 Sou thern Div ision
Developme nt at Lo ugh Ross and Clay Lake , totalling 8 M ild and
imp roved interconnect ion between Castor Bay and
Spe lga/Fo fa nny .
At a later stage , development of the Caml ough source , wh ich
w ill y ield 13 MI/d .
8 .6 Londonde rry/L imavad
The pri ncipal prob lem is the condition of Altnah eglish Dam . If it is to be drawn down for repair some temp orary alte rnative supplies will be needed . Otherwise it is un likely that a new sou rce wou ld be required w ith in the time hori zon of th is study . (xv ) 8 .7 Strabane/Oma gh
W ith the currently planned deve lopment o f Lough Bradan and Lough
Fin grean , further new sou rces do not appear to be neces sary .
8 .8 Fermana gh
Connect ion of Derrylin Borehole to the Ki llyfole supp ly area
to ut ilize a source o f 2 M l/d .
Dup lication of Killyhev lin , producing 11 M l/d w ith interco nnec tion to Killyfole .
INFORMAT ION MDR PLANN ING AN D OPERAT IONS MA NAGEMENT
Consistent , accu rate and regu lar information is requ ired by Water
Service managem ent for effect ive plann ing and control . This pa rt of the study is concerned w ith in fo rmation needed for the mon itoring of supply and dem an d but it is observed tha t imp rovem ents are requ ired also in other areas . The p rincipal matters that requ ire attention are as fo llows :-
9 .1 Wate r Supply
The co llection and transmi ssion of data are gene ra lly sat isfa ctory but the extent to wh ich th is is e ffective requ ires exa mi nation . In particular , the gauging of additional up land catchments is de sirab le .
9 .2 Water Consump t ion
Data on domest ic consumptio n are scarce and it is recommended that the metered district exe rcise carried out for th is stu dy shou ld be adop ted as a basis for further mo nitoring work . For non-dom estic con sum ers the existing meter recording system is not satisfacto ry . The system at prese nt is limited to meeting consumer billing
requ irements and does not readily allow the effective record ing and p roce ssing o f data for p lann ing purposes . Po ints that cause pa rt icular
co nce rn include :
a . Classificat ion of consumers
B . Meter insta lla tion data
c . Accu racy of me t e r s and me ter replacement policy d . Meter sizing
e . Class ification of con sumption data
f . Handl ing of m eter reco rds g . Data presentation .
Acce ss to information from externa l sou rces is also required , and shou ld include popu lation and househo ld characteristic s, economic trend s and local authority development planning . C HAPT ER 1
INT RODUCT ION
1.1 BACKG ROUN D
Th is Study of Water Dema nd and Supp ly in North ern Ire land has been ca rried out for th e Department of the Env ironme nt fo r Northern Ireland by
Sir Alexander G ibb E. Partners jo intly w ith De loitte Hask ins St Sells , Ma nagement Consu ltants . Work comm enced on 5th Sep tembe r, 1983, and interim repo rts were submi tted in O ctober 1983 and January 1984 wh ich rev iewed work ca rried out up to tho se dates . Th is repo rt p resents the conclus ions and recomm enda tions of the Study .
1.2 TERMS OF RE FEREN CE
Te rms of Refe rence for the Study were drawn up by the Water Serv ice of the Department of the Environme nt fo r North ern Ireland 'in conjunction with the Economi cs Divis ion of the Policy , Planning and Resea rch Unit of the Dep artment of Finance and Pe rsonnel and were issu ed w ith the letter of invitation from DOE/N I reference W5 79/8 1 date d 3rd May , 1983 . T hese terms set out the requ irem ent for the study in detail, and give the ob ject ive as follows :-
"The aim of the Study is to determ ine water supp ly needs in Northern
Ireland and in pa rt icu lar Water Serv ice 's Eastern Ar ea ; to exami ne the data on water dema nd and supp ly on wh ich supp lies for No rthern Ire land are p lanned and to su ggest imp rov ements whe re app rop riate ".
Primary requ irements are :
Assessment of pre sent levels of wate r dema nd an d supp ly and
p reparation of p ro jections to the year 2000.
Ana lysis of demand both as to cate gories of ut ilization and spa tia l allocat ion . Exam ination of the scope for increasing transfer of sup p lies both w ithin and betw een supp ly a reas.
Assessment of sa fe yields of existing sou rces .
Re-exam ination o f Unaccounte d For Water (UFW ) levels, including waste , and dete rm ina tion of the co st effectiveness of further UFW
reduction .
Rev iew of the requirements for an effective data base for monito ring
supp ly and demand .
Estimation , in so far as da ta allow s , of the ela st icity of water dem and to p rice .
8 . Assessment of the nee d for a ma jor new water source and developm ent
o f criteria for taking decisions rega rding the developm ent of a new
source .
Recomm endations for the ma in feature s of a strategy for cost e ffective ma na gem ent of the w ater supp ly/demand balance .
1.3 SCOPE OF REPORT
This report pre sents the conc lusions of the work carried out for this study . It does not set out to respond to each of the above qu est ions sepa rately but the requ irem ents of the Terms of Reference are dealt with in the relevant chapters . The rep ort covers all aspects of the Terms of Re fe rence but in som e cases it is necessary to refer to Volum e 2, Supp ort ing Studies fo r matte rs of detail .
Conclusions rega rd ing the yie lds of availab le sources a re p resented in summary and are compa red with re cent production levels . The resu lts of the invest igations into current water consumption are presented together w ith fo recasts for futu re consum pt ion . A rev iew is ma de of unaccounted for wate r , based on consumption and leakage assessmen ts . Leakage reduction is exami ned both as rega rds co sts , possible financ ial bene fits and resou rce requ irem en ts , and also the savings of wate r that may be expec ted . Facto rs wh ich affect the decisions to be taken in plan ning fo r futu re dev elopments are discussed and app raisals are ma de of po ssib le source development from wh ich optimum schemes are identified for a range of
demand forecas ts . These are used as the basis for p lans for each of the p rincipal areas for wh ich deve lopment is required .
Fina lly , the availab ility of data relating to water p roduction and con sump tion for management purpo se s is also discussed , and recommendations made for imp rovements of data retrieva l.
1.4 FRAMEWORK
The No rthern Ire land Wa ter Service is div ided into fou r Divis ions for operationa l purposes and each of these is further div ided into three sub- d ivis ions . In genera l each Division has independent water sources , but in ma ny cases sou rces supp ly parts of more than on e Div ision . The ma jor dema nd centre is the urban area of Belfast, and the wa te r supp lied to the Eastern Div ision , which Includes Belfast , is about 508 of the total used in North ern Ireland . The Divis iona l and sub divisiona l areas are shown on Figure 1.1.
There is some f lexibility in the way that sources can be al located and th is can be of benefit when p atterns of dema nd change as w ell as p roviding safegua rds in condit ions of emergency . However, the degree of interconnection of sou rces in the east of the Provin ce , which supp ly
Belfast and ad jacent areas , mea ns that for planning pu rposes a larger area than the Easte rn Div is ion has to be considered in th is region .
It has been found that the mo st su itab le geograp hical units for the pu rpo se of this study a re the Water Serv ice sub-divisions, s ince much of the ava ila ble data is already allo cated in th is way .
The base year for water consumption has been taken as 198 1, as th is is the latest year fo r wh ich both census data and comp rehensiv e con sump tion inform ation are av ailable . Mi d-198 3 p rices have been used th rougho ut for cap ital and operating costs , excep t where account has been taken of increasing energy costs . COLERAINE
e / ,.... .-- -) / 7 . / l.4 i LONDONDERRY I? •
k- „ Ij O R T H E R N ( .#-2--) (\ \-1/4 e---/ ------BALLYMENA / ..... ANTRIM ) .•••••••• 4.1 t / ( \ 2 WESTERN Ni ....X BELF41"STfr , AL OMAGH i f I , ./ I 5( .....".^- ..-N. ..) i ‘ -n E A S T E R N 1 , —r t.) t ISBURN/ ( / j -- ... \ N CRAIGAVON r / %.\ k r ...... , ARMAGH \ ,.\ ..../ - 4"-\ / DOWNPATRICK \ ...., "' 1 i r b.31/41, L .." ,
. .. " • SOUTI:IERN ENNISKILLEN ( \ 1i 3 \ ,---- i NEWRY ) Nr •S /j "N . 'Nes-1 1 1,S i e ( f t ' kg... j ,%.7 ...."
NORTHERN IRELAND WATER SERVICE DIVISIONAL AND SUB - DIVISIONAL AREAS Figure 1 1 1.5 ACKN OWLEDGEM ENTS
Th is Study has been unde rtake n with the assistance of
Fergu son & McIlveen , Con su lt ing Engineers , Belfa st Inst itute of Hyd ro logy , Wa llingford Mr . H. Spe igh t, Water Ma na gement Consultant , Ferrin g, Sussex .
In carrying out the work the study team ha s been greatly assisted by membe rs of the sta ff of the Water Se rv ice , bo th at Headquarters and at
Divis io na l 'Office s , and the Econom ics Div ision and So cia l Research Division of the Policy Planning and Research Unit .
In addition , acknowledgement is giv en to assista nce received from a number of o ther organ izations whom we have consu lted , as follow s :-
Office of Public Wo rks , Dub lin No rth West Water Authority , Warrington
South West Wate r Authority , Exeter
1.6 ABBREV IAT IONS
A lis t of Abbrev iations used in th is report is given in Appe nd ix 11. CHAPTER 2
OUTPUTS FROM WAT ER SOURCES
2.1 INT RODUCT ION
One of the rea sons for this study is the concern that has arisen in recent years regard ing the ab ility of av ailable sources to meet the inc reasing demand for wate r . As a first step , there fore , it is necessary
to consid er the capacities of these sourc es in relat ion to the dem ands that
have been put on them . This chapte r discusses the assessments of reliab le yields and the av ailable production capac ities of sources and relates them
to the quantit ies of water that have been produced in recent years .
2 .2 YIELDS OF SOURCES
2.2.1 App roach
The ob jective of th is work ha s been to ass ess the reliab le yields of existing and pote ntial water source s . Su rface w ater sou rces are the most
important , pa rticu larly upland reservo irs and loughs , but attention has also been given to groundwa ter . The app roach for upla nd sources has been
to develop a regiona l sto rage/yield relationsh ip for Northern Ireland , based on available rive r flow records au gmented by meteorolog ical reco rds .
Th is chapte r summarise s the conc lus ions of the work wh ich is described in
detail in Volum e 2 .
2.2.2 Yields from Rese rvoirs
Regiona l sto rage/y ie ld relationships have been developed as a basis for the as sessment of reliable yields for all of the re levant sou rces .
Average runo ff is ca lculated from standard annua l av erage rainfa ll (SAAR )
adjusted for evaporation and catchment area . For indirect catchmen ts 803
o f the catchment area is used , except for a few sites wh ere more deta iled
informa tion is available . The resu lts are given in Volume 2 and the gro ss y ields listed mu st be adjusted for compensa tion water where th is is
req uired . As we ll as existing works , the invest igat ion included sev era l proposed schem es which are considered in deta il el sewhere in th is rep ort . Yie lds from surface sources have been assessed on the basis of failu re frequencies o f 1 in 20 and 1 in 50 years . Conside ration has be en given to the effects of ration ing wh ich are discussed in Chap te r 6 and
Vo lume 2.
2 .2.3 River Abstra ctions
The impo rtant sources invo lv ing direct ab straction are :
Eastern Division
Riv er An nalong . Th is has bee n inc luded in the assessm ent of the y ield from the Silent Va lley System .
No rthern Division
River Bann at Castleroe . The yie ld of th is sou rce is limited
p rima rily by the cap acity of the intake .
Western Division
River Faughan at Ca rmoney . This has been repo rted on in detail by Binnie A Partne rs in Decemb er 1969 . The output is lim ited by river
conditions to 36 M l/d . River Derg a t Tievenny . Work based on the Institute of Hydrology 's Low Flow Study estima te s re liable y ields for 20 and 5 0 year return periods at 9 .4 and 6 .9 M l/d respectively .
2 .2 .4 Lou gh Nea gh
Th e conclusions of the Lough Nea gh Workin g Group (197 1) were that la rge quantities of w ater could be taken from th e Lough with very litt le adverse effect . It is essential , however , that a so lu tion to the algal p roblems shou ld be found in the near futu re . For the p ractical purpo ses of the p resent study it is the refo re concluded that all foreseeab le dema nds for p otab le water on bough Neagh can be m et . 2 .2 .5 Groun dwater
The complex geo logy of North ern Ire land results in aqu ifers of
limi ted extent and yie ld . Recent groundw ater developm ent has increased
tota l pump ing capacity but is not wholly ut ilized . The quantit ies derived from grou ndwater sources in 1982 a re given in Table 2 .1.
TAB LE 2 .1
GROUNDWATER PRODUCT ION TN 198 2 (MI/d )
Divis ion Bo reho les Springs & W ells
Eastern 1241
North ern 1 13 Southern 11 1 Western 3 7
TOtal 27 21
*Note : G roundwate r supp lies to the Easte rn Divis ion are bein g
augmented by the comp letion of th e Lagan Va lley Bo reholes wh ich are expected to increase this figu re by about 20 M l/d .
In Northern Division , developments at Glarryford , Buckna and Drumb est are expected to add abou t 12 M l/d .
2.3 AVA ILABLE PRODUCT ION CAPAC IT IES OF SOURCES
The re lia b le outpu ts which can be made availab le from those sources wh ich are cu rre ntly in use are listed in detail in Appe ndix 1 and summarised in T able 2.2. These are based on the forego ing sections , but accou nt has been taken of the fo llow ing, where app rop riate.
(a) Yields from up land sou rces are based on 1 in 50 year failu re crite ria . (The qu estion of the failure criteria to be used in
resource plann ing is discussed later in this report ). (b ) Constra ints impo sed by the cap acities of water treatment plants , pump ing stat ions , aqueducts and p ipelines .
(c ) Quantit ies used for trea tment processes , such as in washing f ilters or in sand wash ing p lants .
(d ) Compensation wa te r or prescribed flows .
(e ) Groundw ater inc ludes sp rings , we lls and bo rehole s .
TABLE 2 .2
SUMMARY OF CURRE NT LY AVA ILAB LE SOU RC ES
Note s . (1) Washw ater deducted
(2 ) Prescribe d flow deducted (3 ) Proport ion only
(4 ) Further developm ent of Lagan Va lley bo reholes will add
16 .5 Ml/d by 1987 . b . No rthern Div is ion
M l/d
Killy lane 13 .0 (1) Du ngonnell 11.9 ,(1)
Qu olie 5 .0 (1)
Lou gh Fea 13 .2 (1) Ba llinrees + River Bann 33.1 (1)
A ltnah inch 10.7 (1) (2 ) Lo ugh Neagh (Duno re ) (3) 18.0
Moyo la 13.0
Mino r Sources 10.8 (1) Groundwater (4 ) 18 .3 147 .0
No tes . (1) Washwater deducted
(2 ) Presc ribed flow dedu cted (3 ) Rated output of tre atment works (4 ) Propo rtion on ly Notes . (1) Washwater deducted
(2 ) To increase by 6 .6 M l/d
(3 ) To increase by 4 .8 Ml/d
2 .4 WATER PRODUCT ION
2 .4.1 Annual Avera e Produ ction
The annua l average rates of prod uc tion of water are availab le from the W ater Service records and these are summa rised in Table 2 .3 for ea ch Divis ion for the years 1973 to 1983 inclus ive . The figur es for the Eastern Div ision have been adjusted to allow for m eter errors which were ident if ied a nd corrected ea rly in 1983.
Th ese figures indicate tha t except in the Eastern Divis ion the genera l trend of w ater p roduction has been rising steadily ov er the last ten years although levelling off generally from 1979- 1980 . In Eastern
Div ision p rod uction rose to a peak in 1979 and then fe ll sharp ly during
198 0 and 198 1. This was due to the closin g of water consumi ng industries du ring th at pe riod , pa rticularly the Courtaulds factory at Ca rrick fergus .
Produc tion has however continued to rise between 198 1 and 1983 . If the requ ireme nt o f Courtau lds (about 25 Ml/d ) is removed from the earl ier years the underlying trend for the ,Easte rn Division is also rising . The trend line grow th has been ana lysed for each Div ision and is shown graphical ly in Figures 2.1 and 2 .2 .
- 10- TABLE 2 .3
ANNU AL AV ERA GE WAT ER PRODUCT ION
M l/d DIV ISION
Year Easte rn North ern Southe rn Western Tota l
1973 284 87 84 79 534
1974 306 89 93 85 573 1975 3 14 90 9 1 8 1 576
1976 309 90 105 82 586
1977 325 101 107 92 625
1978 33 1 108 105 99 643 1979 339 106 120 98 663
1980 328 118 120 109 675
198 1 307 114 118 107 646 198 2 320 116 120 107 663 1983 335 118 123 111 687
The increases in wa ter product ion for ea ch Div ision over the ten y ea rs are :
Total An nual compound growth increase 1973- 1983
Overall Based on trend analysis
Eastern 18% 1.7% 1.0%
(exc luding Courtau lds ) '29% 2.6% 2.0% Northern 36% 3 .1% 3.5% Sou thern 46% 3.9% 3.7% Western 4 1% 3 .5% 3.7%
The lower trends for Ea stern Division are in pa rt due to the imp lementation since 1976 of mo re effe ctive wa ste co ntrol. PRODUCTION MI/ d
400
350
300
oft Trend line 2 0 % p a.
es. a s.
a d.
woo
250
200 1973 1g74 1975 1976 1977 1978 1979 1980 1981 1982 1983
NOTE : 1973 - 1979 exclude Cour toulds consumption
ANNUA L AVERAGE WATER PRODUCTION EASTERN DIVISION Figure 2 . 1 PRODUC T ION MI/d 130
120
110
ow. 100 Trend line 3- 5 % p.a.
90 ow.
NORTHERN DIVISION 80 1973 1974 1975 .1976 1977 1978 1979 1980 1981 1982 1983
130
40 '
120
.•••• 4. 0
110
Trend l ine 3- 7 % p a. 40 ' 100
• ••
90
SOUTHERN DIVISION 80 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983
120
110 40 .
100
Trend line 3.7 % p a 90 ..• •• • ••
80 ••
70 WESTERN DIVISION 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983
ANNUAL AVERAGE WATER PRODUCT ION Figure 2 .2 Wh en comparing the water produ ct ion in 1983 w ith the availab le p ro duction cap ac ity given in Tab le 2.2 it is evident that cu rrently the effective ma rgins in mo st D ivisions are no t great althou gh some addit iona l sou rce cap ac ity is being deve loped . In some local a reas the po sition is critical . If the past growth rate s indicated above are mainta ined the se ma rgins will very soon be used up . Thus it is clear that the conce rn for the futu re po sit ion is fully just ified .
2 .4 .2 Seasonal Variations
Of recent years , mon th ly water production has tended to reach a peak during the w inter, and th is is p robably a reflection of the e ffect of bu rst p ipes during very cold weather . Th ese effects tend to obscu re summer pea ks but exam ination of month ly data for 198 3 (a year for w hich w inter p eaks were less prom inent ) indicate s that significant summer peaks can occur .
Wh ile meet ing w inter p ea ks may not p resent ser ious p rob lems , summer pea ks are mo re diff icu lt to satis fy , pa rt icu larly where rese rvoir sto rage cap ac ities in small upland sou rces are limited . Thus the app licat ion of 1 in 50 year reliab le yie lds for such sou rces must take acco unt of the relevant seaso nal demand f luctuat io ns .
- 12- C HA PT E R 3
WATER CONS UMP T I ON
BASE YEAR CON SUM PT ION
3 .1.1 Introdu ct io n
In acco rdance w ith ge ne ra l p ractice in the UK su pplies to mo st do m es t ic p rem ises a re not m etered a nd the re le v ant w ater ch a rges are
re cove red th ro ugh dome st ic rates . Non -domest ic con sumers are ge ne ra lly m ete red and charges ma de on the bas is o f w ater con sum e d As a co nseq uence th e re is no d ire ct mea su rem en t of domesti c co n sum p tio n but in fo rma t ion for non-dom e stic consum ers is ava ilab le from m eter record s . It h as the re fo re bee n ne ce ssa ry to adop t sepa rate ap p roaches to the assessmen t o f dom est ic and n on- do me stic con sum p t ion fo r the ba se year (198 1).
3 .1.2 Dom e stic C on sum t io n
1. App roach
Est im at es of dom est ic water co nsump t ion have be e n deriv ed fro m th e results o f a d istric t met ering exe rcise ca rr ie d out by the Wa te r Serv ice
Eo r th is su dy . Th is ap proach invo lv ed me a su rin g the quantit y of w ate r use d in a n umb er of sma ll w ell-de f ined resid en t ia l areas and , by com b ining this w ith po pu la t io n and prope rty data , ob ta in ing e st im at es of ave ra ge consum pt ion p er p e rson . Tota l dom estic w ater consum p t ion for each wa te r su p ply su b -d iv isio n was then asse ssed usin g po pu latio n estim ates ob tained from the 198 1 No rthern Ireland Cen sus o f po p ulat ion a d justed to tak e accoun t o f th e im pact of cen sus no n -enu m eratio n in ea ch sub -d iv is io n .
- 13- 2 . Mete red Districts Exerc ise
Districts were se lected as far as poss ible to meet the following criteria :-
(a ) sma ll m ete rab le area with known low waste levels where
po ssible ; (b ) app rox ima te ly 30 residential prope rties with no non-dom est ic
p rop erties ; (c) prope rties of similar type (for examp le small terraced or large detached ) with in each ind iv idual district ; (d ) rep resentatio n of prope rt ies of differen t type across
different areas .
New app ropriately sized (generally 1") meters were insta lled in each district and week ly co nsumption vo lumes were m easu red during th ree sep arate periods ;
(a) November/De cember 198 3 ; (b ) February/March 1984 ;
(c ) June 1984 .
The June 1984 readin gs also inc luded hourly nightflow informat ion measu red on two separate nights for each met ered d istrict . This informa tion wa s no t co llected for the two ea rlier sets of readings . All resu lts have been screened by the Wate r Se rv ice in order to exclude m isleading informatio n , fo r examp le where there was clear ev idence of meters ma lfunctioning or of ma jor water loss due to bu rst mains . It was further necessary to exclude a number of obse rvat ions where there were informa tion de ficiencies , for example concern ing the dates and tim es at which readings were taken . Tab le 3.1 summ a rises the coverage of the exercise .
Further data we re co llected for each di strict concerning numb ers of p ropert ies and po pu lation . Of the 73 d istricts, rough ly 50 were survey ed in fu ll us ing the questionnaire developed fo r the ma in househo ld survey
(see Vo lume 2 ) while the rema ining districts w ere su rveyed for population only . Details of the dist ricts inc luded in the exerc ise are given in Vo lume 2.
- 14- TAB LE 3 .1
Note : Th e 73 dist ricts surveyed in Ju ne 1984 include all the districts
wh ich were surveyed in Novemb er/Decemb er 1983 and in Febru ary/Ma rch
1984 .
A lthough districts we re se lected on the basis of known low waste levels , i t is necessary to ma ke a deduct ion to take account of waste in a rr iving at estimates of consumption . The max im um poss ible lev el of
leakage in any d istrict may be established by re ference to the m inimum
night flow ; the rate of leakage cannot exceed the lowest observed rate of flow . Some consumption ma y , how ever , take place at the p oint of m in imum n ight flow either directly , due to night use of water-using app liances/ am en ities , or ind irect ly , due to tank-filling fo llowing earlier activ ity .
If leakage levels are ca lcu lated direct ly from the minimum nigh t flow w ithout taking account of th is element of "legitimate n ight co nsum ption " the estima tes of dom est ic consumption will unde rstate true water usage .
Data conce rning legitima te night con sump tion were not co llected for the mete red districts exerc ise . Th is wou ld have requ ired ma jor addit ional work w hich w as not po ssib le w ith in the scope of this study . It was there fo re necessary to estimate the extent of domestic night u sa ge by re ference to other stud ies.
- 15- DOE/NWC Report 26 , 'Leakage Control Po licy and Practice ' recomm ends
that a maximum deduction o f 2 litres/prop erty/hour (l/p/h ) should be made
from the obse rved mi nimum night flow rate (ca lcu lated from readings taken at 15 m inute inte rva ls ) in order to assess tota l leakage . This m ethod is ,
however , intended for app licat ion to relative ly large areas with 1,500 or
more prope rties .
Water Rese arch Centre Repo rt No . 154 , 'The Resu lts of the Expe rimenta l Programme on Leakage Control ', up on which the NWC Rep ort 26
procedure is based , indicates that the figure of 2 l/p/h was calcu lated on the bas is o f the ave rage of flows taking p lace over a number of night
hours . The level of leg itima te consump tion tak ing p la ce duri ng the minimum hour is likely to be som ewhat lower than this average . This supports the argument that an av erage deduction from mi nimum night flow of 2 l/p /h may
be excessive for the purpose of calculating leaka ge . In a number of areas
the deduction of two litres from the mi nimum night flo w would have resulted in a negat ive est ima te of leg itima te con sumpt ion .
In the very much sma l ler districts used for t his exercise the re is
likely to be a closer correspondence between the m inim um observed flow and the leve l of leakage . Th is is because the times of mi n imum ni ghtflow va ry
significant ly between d iffe rent small groups of p rop er ties .
Fo r the prese nt stu dy , the ad justment for domest ic night consumption has been made depe ndent on the mi nimum night flow evident in each district .
Wh eneve r the observed minimum ni ght flow exceeds 2 l/p /h a deduction of 2
l/p/h has been ma de . In those cases whe re the m inimum night flow fa lls
be low 2 l/p/h all of this flow has been treated as consumption . The
resulting ave rage deduction ma de for legitima te night consump tion amounts to 1.1 1/p/h .
Daily leaka ge figu re s have been calculated from the resu ltant estimate of ni ght leakage rates using the recomm ended factor o f 20 to ma ke allowance for higher night pressures . The leaka ge figu re calc ulated for each district based on the results of the Ju ne 1984 su rvey have been app lied to the p re vious Novembe r/December 1983 and Ma rch 1984 su rvey results for these pe riods .
- 16- Ta b le 3 .2 summ ar ises the results of the metered districts exercise , b reak ing down the re sults by Water Service Div ision . The figu res shown in row (A ) for each D iv ision include all th ose ob servations whe re no specific p rob lem is known to have occu rred . The figures in row (B ) exclude all obse rvations for six dist ricts where the resu lts of the survey were considered to be su spect , either because of exceptiona lly great variation between the read ings taken for di fferen t survey pe rio ds , or because th ey rep re sented ex trem e (high or low ) o utliers when compa red w ith the results for other districts .
Th e figures in Table 3 .2 show marked variation between Divisions in net consumption per capita . Divisional results are however ba sed on a re latively sma ll samp le of dist ricts in each case and it is there fore not po ss ib le to ascerta in w he ther this variation can be attributed to systema tic difference s (for examp le qua lity of housing stock , tenur e patterns etc ) between Div is ion s or to samp le variation . Beca use of th is , attentio n ha s been concentrated on the re su lts for the Provin ce taken as a who le .
Som e informa tion concerning the pa tte rn of seaso nal variation is evident from the figu res shown in row (C ) for each Div ision . The se figu res includ e on ly tho se forty districts for wh ich o bserva tions were ma de for all three survey periods . The overa ll figu res for th e Province suggest tha t there may be seasonal variatio n between winter and summer consumption amoun ting to app roximate ly 10% of ave rage w inter consump tion .
In order to take accoun t of seasona l varia tion equal we ight has been giv en to the June readings and to the av erage of the two earl ier read ings as a means of ad jus ting for sea sona l varia tion . This is show n below based first ly on all ob servations (rows (A ) in Tab le 3.2) and secondly on all obse rvations ex cludin g outliers (row s (B ) in Tab le 3 .2 ).
(A ) OVERALL AVERAGE CONSUMPT ION = (0.5 x 127 .7 ) + (0 .25 x 120 .9 ) + (0.25 x 126 .8 ) = 125 .8 litres/pe rson/day
(B ) OVE RALL AVE RAGE CONSUM PT ION = (0.5 x 129 .5 ) +
(0.25 x 113 .6 ) + (0.25 x 112.0 ) = 12 1.2 litres/p erson/day
- 17- 111111 110 111111 M I S1M 111111 SP INE 11.11 111111.„ 111111 a a S . HS 111111 1• 11 HS 111111 TABLE 3. 2
pe:u.K1 0 1sil t ICTS SD/WARY OF RESULTS
( C) I nc l ude s onl y d i s t r i c t s whe r e r ead i ng s wer e t ak en f o r a l l su r vey A l l co nsumpt i o n r e su l t s a r e we i ght ed by pr o pe r t y numbe r s i n eac h d i r r r i c t . pe r i od s ( i e Ju ne 1984 , Feb / Mar c h 1984 , Nov / Dec 198 3) . Th i s app r oac h e l i mi na t e s t he i n f l ue nc e o f co r r e l a t i on bet ween ho u sehol d s i ze and ave r age pe r cap i t a wat er co nsumpt i o n o n o t i mat ed av e r age consumpt i o n pe r per so n.
Domen i c n i gh t con sumpt i o n a l l owed f o r by ded uc t i ng t he l e aser o f t he mi n i mum n i ght f l ow pe r p r o pe r t y per ho u r and 2L pe r p r o pe r t y per hou r .
3 Per i od 1 a J u ne 1984 Pe r i od 2 Feb r ua r y/ Marc h 198 4 Per i od 3 a Nov embe r / December 198 3
• ••• •• • •• The me te red districts exerc ise thus indicate s av erage 198 3/84 per
capita consumption lev els betw een 12 1 an d 126 litres/day . A figu re of 125 litres/pe rson/ day has been used to derive base (198 1) domestic consum ption
est imates for the present study . It is considered unlikely that the
average pe r cap ita consumpt ion in 198 1 exceeded this figu re fo r the
fo llow ing reasons :
(a ) avera ge consumption in 198 1 is like ly to have been somewhat lower
than in 198 3/84 (the survey p eriod ) 'due to consumption grow th in the
inte rvening years ; (b ) the mete red districts survey include d a hi gher proportion of private
housing than is ev ident from the NI Census ; rew eighti ng to take accoun t of this wou ld have resu lted in an approximate ly 3% reduct ion
in the ave rage consumption estima te due to the typically higher than average con sumpt ion of households in private housing .
Set aga inst these facto rs is the fact that the night flow figures
used to calcu late leaka ge rate s were based on Saturday night rea dings which may be marg inally higher than mi d-w eek values . Given the inev itable
unce rta inty regard ing average consumption , it wa s the re fore considered
ina dv isable to ma ke any deductions to take accou nt of the fac to rs noted
abo ve .
3. Estima tes of Domestic Water Consum tion b Sub -divis ion
Est imates of domestic water consumption by sub-d ivision have be en obta ined by comb ining the 125 litre s/person/day consumption figure obta ined from the me tered dis tricts exercise w ith po pulation estimates obta ined from the 198 1 Census of Pop ulation . It ha s been assumed that there is no var iation in pe r cap ita consump tion throughout the Province .
It is known that a significant propo rtion of the Northe rn Ireland resident po pulation w as not en um e rat ed in the 1981 Popu lation Censu s . Tab le A 2 .1 in Appendix 2 gives est ima tes of non-enum erated popu lation for ma jor population centres in the Province as agreed by the inter- depa rtmen ta l work ing pa rty estab lished to exam ine this issue . Th e figure exceeds 10% in bo th Belfast and Lo ndonderry local gov ernment districts .
Table A 2.2 show s estimates of non-enum erated population as a pe rcentage of enum erated population for each sub-d iv ision .
- 19- Overa ll dom es tic consum pt ion es tima tes for 198 1 a re shown by sub-
div ision in Tab le 3 .3 wh ich also shows estimated popu lation including the
allowance for census non -enumerat ion .
3.1.3 Non-Dom estic Consum tion
Estima tes of non-domest ic consump tion have bee n based on mete red consumption data Eor 198 1 p rovided from water charging records . A
significant numb er of non-dom estic consume rs is know n not to be metered and allow ance w as m ade for th is based on a compa riscn of the numbe r of meters
fo r each ma jo r catego ry of consum er togethe r w ith comp arable figu re s on the total numbe r of estab lishm ents in that ca tegory based on the 1981 Censu s o f
Emp loyment .
Non-dome stic wa te r consumption is high ly concentrated in a ve ry sma ll p rop ortion of consum ers . The a llow ance ma de for consumption by non-mete red
non -domestic use rs has been based on the assumption that these did not
inc lude su ch very la rge consumers . Th is ana lysis is described in detail in
Vo lum e 2.
A samp le su rvey of non-domest ic water use was also carried out in order to investigate the re lationships be tween employment (or other
app rop riate act iv ity variab les ) and wa ter consump tion in indiv idual es tablishments . How eve r, the resu lts of th is an alysis do not p rovide a
re liab le basis for wate r dema nd estimation due to the ve ry sm all samp le
size which could be o bta ined and to the d iff iculty of associating
indiv idua l mete rs w ith emp loyment in ind iv idua l estab lishments .
Ev idence has been p resented concerning sy stem at ic under-reading of ce rtain trade me te rs . Te sts carried out by Eastern Div ision in 1979 on 175 Fro st m ete rs show ed that the 110 which we re func tioning were unde r- registering by an avera ge of 5% at full flow condit ions . A fo llow -up investigation ca rried out in February 1984 show ed about 6% unde r- registra tion at both ha lf and fu ll flow levels . Under- registration at very low flow leve ls ma y be much higher . Tests on 25 Kent m eters unde rtaken in Newry sub-d ivis ion in 1977 showed an average unde r-reco rding of 46% at a flow rate o f 6gph (27 l/h ), reducing to 10% at 16gph (73 l/h ) w ith negligib le under-regis tration at full flow leve ls .
-20- TA BLE 3 .3
BASE YEAR DOM EST IC CO NS UM PT ION A ND PO PU LA TION
EST IMA T ES BRO KEN DOW N BY SUB-D IV IS IO N
BASE (198 1 ) BA SE (198 1)
PO PUL AT ION C ONSUM PT ION
( '000s ) (Ml/d )
EA STE RN DIV IS ION
Be lfa st 448 55 .95
Downp atr ick 156 19 .48
L isburn 122 15.23
Tota l 725 90 .66
NO RT HE RN DIV IS ION
An tr im 86 10.78
Ba llymena 118 14 .72
Co le ra ine 83 10.39
Tota l 287 35 .89
SOUTH ERN D IV IS ION
Arma gh 80 9 .98
C ra igavon 78 9 .72
New ry 108 13.47
To ta l 265 33.17
W ESTERN DIV IS ION
En n iski lle n 58 7 .22
Lo ndonderry 117 14 .62
Oma gh 82 10.30
T otal 257 32.13
-21- It is no t po ssible to assess the fu ll effect of this me te r un der- registration w itho ut add itional in forma tion concerning :-
(a ) the sizing of meters in re lation to indiv idua l consumption
flows ; (b ) the propo rtion of mete red consump tion taking place at very low
flows .
For the pu rpo ses of assess ing tota l metered consumption fo r the p re sent study an add ition o f 10% has been made to tota l metered demand estimates . Th is has been shown separate ly due to the conside rab le uncertainty concerning its value . It is recommended that further w ork be ca rried out on this qu est ion ; first to assess the overa ll impact of under- reg istration on consum ption estimates and second , to a ssist in the eva luation of mete r rep lacem ent po licies . Tota l reven ue obta ined from metered water consump tion is of the o rder of £ 8 m illion per annum , suggest ing that the loss of revenue may be as mu ch as 48 00,000 per annum .
3.1.4 Ove ra ll Consump t ion Est ima tes
Overa ll estimated consumption for 198 1 is shown in Ta ble 3.4 for each sub-divis ion broken down by b road consum er categories . Detailed figu res are giv en in Appendix 4 , Tab le A4 .1.
-22- TABLE 3 .4
SUMMARY OF BASE YE AR (198 1) C ON S UMPT ION E STIMA TES
SUB- D IV IS ION DOME ST IC NON -DO MEST IC 1 T OT AL
Inc ludes op era t io na l/ usage and add ition o f 10 % to tak e accoun t of
est ima ted mete ring er ro rs .
Som e figu re s do no t add du e to round in g .
-23- 3 .2 DOMEST IC CoNSumPT I ON FORECAST S
3.2 .1 Genera l
Fo recasts of growth in domestic con sumpt ion have been ba sed on pro jecting the impact of thr ee key factor s :-
(a ) growt h in populat ion ;
(b ) imp rov ing sta ndards o f livin g ;
(c ) changing househo ld size .
Th e latte r two facto rs w il l tend to resu lt in increases in avera ge per capita con sumption , whereas the former has a direct impa ct on numbe rs o f co nsume rs .
In the fo llow ing pa ragraph s ea ch of the above effects is asse sse d sepa rate ly . Th ey a re then comb ined to prov ide ind ices of ove ra ll grow th in dom est ic co nsumpt ion .
3.2 .2 I act of Po u lation G rowth
Pro jections of population fo r local gov ernment distric ts have been obtained from DOE Planning . The total projected grow th in NI popu lation implied by these figu res has be en ad justed so as to agree with the range of p ro jections in tota l popu latio n growth supp lied by the Po licy P lanning and
Re se arch Unit (PP RU ) of the Depa rtm ent of Fina nce and Personne l . Th e to tal of the loca lly based figu res amounted , be fore ad justm ent, to som e 2 .1% less than the PP RU mi d fo reca st fo r all NI in the yea r 2000 .
The ov era ll grow th in populat ion be tween 198 1 and 2000 ranges from a low growt h assumpt ion of 4% to a high assum ption of 18% . The range of growth assumptions fo r NI and for each Wate r Supp ly Div is ion is shown in
Tab le 3 .5 . Growt h ind ices by sub-divis io n are shown in Appendi x 3 .
-24- TABLE 3 .5
PO PULAT ION PROJ ECT IONS BY D IV ISION
198 1 NI Census o f Popula tion adjueted for e st imated non-
enum era tion
-25-
L2" 3.2 .3 act of Im rovin Livin Standards
The re is l ittle d ire ct ev id ence on the impa ct of a higher general standa rd of liv in g on domest ic w ate r consumption in No rthe rn Ireland .
Increasing pers onal d ispo sab le in come and the consequent increase in
app liance ownership , comb ined with new housing development and the
renovation of ex isting p roperties , can how ever be expe cted to lead to a
greate r use of wate r by Northe rn Ireland house holds .
Ave rage w ater consumption p er cap ita can be expe cted to grow in line
with increased ac cess to wa ter us ing app liance s and amen ities . Pro ject ion s
of the increased ownersh ip of the se com ponen ts of dema nd have the refo re
been u sed to fo rm th e basis of the fore cast Impact of standards of living on domestic con sumpt ion .
Table 3 .6 show s ownersh ip of water using app liances/ame nitie s in Northe rn Ire land together w ith comp arab le fi gu res for GB . A number of
sou rces have been use d to de rive these figu res namely :-
(a ) the m ain su rvey of about 2,500 househo lds ca rried out during the
course of th is study ;
(b ) the 1983 NI Continuous Househo ld Su rvey ;
(c ) the 198 1 NI Censu s of Popu la tion ; (d ) the 1982 GB Gene ra l Househo ld Survey ;
(e ) studies by the En glish Wate r Autho rit ies repo rt ed in Nationa l Water
Council Occasiona l Technical Pape r No . 6 , Ju ne 1983.
Th ere is a goo d co rrespo ndence betw een th e resu lts of the ho useho ld su rvey ca rried out for th is study and the ev iden ce prov ided by th e N I
Con tinuous Hou seho ld Su rvey (bo th 1983 ). Th e 198 1 Ce nsus figu res for baths/showers and inte rnal WCs su gge st that th ere has be en some growt h
s ince 198 1 in ac cess to these ame nities . Compa rison with the Gene ra l
Household Su rv ey howeve r shows th at NI househo lds lag beh ind G8 househo lds in ownersh ip of app liances/am enitie s (by approx ima tely 10 years for bath s/show ers , 3 years for inside WCB and 8 years for w ashing mach ines ).
Th is pattern will be mo re marked in terms of own ersh ip pe r cap ita because of the gene ra lly larger ho useho ld size in the Provin ce .
-26- M O a a ONI N M 10 1 a ININ NM OM IIMI • MN M I a l= 1 M O M
TABLE 3 .6
OWN ERS HIP OF WATER US ING A PPLIANCES/AM EN IT IES
N I Househo ld Surve (198 3)
N I Avera ge N I Continuo us NI GB Genera l En lish RWA Stu dies
(We ighted by Ho use ho ld Census of Househo ld South Severn Thame s An glian Own er Pub lic Other 198 1 Cen sus Su rvey Pop u lation Survey West Trent
Unweighte d resu lt from ho useho ld survey Figu re 3 .1 show s the pattern of grow th in ownership of wa ter using app liances/amenities in GB evident from Ge nera l Hous eh old Survey statistics . Th ere has been steady grow th in every category , alth ough grow th in access to baths/show ers appears to have leve lled o ff since 1980.
It is not clear wh eth er this is attributab le to a °saturation effect " or to the impact of economi c recession .
Th e avera ge rate of growth in ownersh ip of the se appliances/am enit ies in GB over th is pe riod is summarised below :-
p .a . (not compound )
It is reasonable to assume that N I own ership of these items wil l grow in line w ith GB experience as stand ards of liv ing imp rove. Rates of grow th ca n be expe cted to decline however as pe netratio n incr eases (the ownership percentages are de fined in term s of the p roportion of households with one or more of each item , so that 100% own ersh ip is the maximum po ss ible in ev ery case ). Table 3.7 shows assumed high and low p ro jected levels of own ership in N I. (198 1 levels have been pro jected ba ckwards from 1983 data whe re necessary .)
TA BLE 3 .7
PROJECT IONS OF OWN ERSHIP OF WATER USING AP PLIANCES/AME NITIES
T ropo rt ion of NI Hou seho lds Ownin g Applian ce/Ame nity (8 )
-28- With sole use bath / shower 100
Wit h sole use inside w.c.
80
Wit h washing machine
60
40
20
1971 1972 19731974 1975 1976 1977 1978 1979 1980 1981 1982 1983
SOURC E GENERA L HOUSEHO LD SURVEY 1982 .
TRENDS IN HOUSEHOLD OWNERSHIP OF WATER- USING APPLIANCES IN GREAT BRITAIN Figure 3 .1 In order to assess the impact of increasin g app liance ownership on average dom estic water consump tion it is necessary to weight these figu res by the proport ion of water consumption attributab le to each item . No NI evidence is av ailable concern ing this , but the Regional Water Authorit4
studies provide an ind ication of the appropriate propo rtions as shown in Tab le 3 .8 .
T ABLE 3 .8
WAT ER USE BY COMP ONENT S
Avera ge Co nsumption Average from RWA Studies Own ership .'
Source - RWA stu dies or Genera l Hou sehold Survey where RWA figure s not available . Garden Sprink lers.
'The combination of the high and low ownership pro jections shown in
Tab le 3 .7 w ith figures from Table 3.8 (used as weights ) implies the mid and
low average consump tion grow th indices shown be low in Table 3 .9 . Th e high p ro jec tion in th is tab le is based on high grow th in app liance own ersh ip comb ined with the assump tion that the rate of use will increa se from 198 1
to 2000 by 25% for ba th s/showers (due to greater frequ ency of u se ), by 10% for wash ing mach ines (due to increased owne rsh ip of automatic machines ) an d by 50% for sp rink lers . M iscellaneous consumpt ion has been assum ed to grow
in proportion to total consumption attributed to components in each case .
-29- TABLE 3 .9
IMPACT OF IMPROV ING LIVING STA NDARDS
(AVERAG E CONSUMPT I ON GROWTH INDICE S )
3.2 .4 Im act of Fa llin Hous ehold Size
Household size affects water consumption due to economies of sca le in
water usage . The resu lts of the RNA stud ies concerning this factor are summarised be low in Table 3 .10.
TABLE 3 .10
DOMEST IC WATER CONSUMP T ION FOR DIFFERENT HOU SEHOLD SIZE
Reduced househo ld size can therefore be expe cted to resu lt in h i g h e r average consumption levels in NI.
Th ere has bee n a distinct tre nd tow ards smaller household size in the Province . Table 3 .1 1 shows movem en ts in pe rso ns in each househ old size ban d be tween the 197 1 and 198 1 popu lation censuses , to gether with
comparative figu res fo r En gland and Wa les .
-30- TABLE 3 .11
C HANGES IN HOUSE HOLD S IZE
Northern Ire land England and Wales
100 100 100
Ov e rall average househ o ld size 3.4 3.2 2 .7
It is lik ely that the size compo sit ion of hou seh olds in Northern
Ire land will become inc rea singly close to that in En gland and Wales although chan ge wi l l probably be gradua l.
Projected hou seho ld size compo sit ion in Northe rn Irelan d has been ba sed on the linear extrapo lation of past trends in househo ld size composit ion in the Prov ince . This is shown diagramatically in Figu re 3 .2 . A range of 25% above and be low the central p ro ject ion of change in househo ld size composition has been assum ed to allow for uncertainty . Tab le 3 .12 shows pro jected household size compo sition for 1990 and 2000 together with corresponding va lues for persons by household size band .
The impact on average water consump tion of changing household size composit ion we ighte d by average consumption by househo ld size from Table 3 .12 is shown in Tab le 3.13. PERSONS PER HOUSE HOW
30 2
25
20
4 3
10
6
1955 1965 1975 1985 1995
SOURCE : CENSUS OF POPULATION 1951, 1966,1971,1981.
CHA NGE OF HO USEHOLD S IZ E IN NORT HERN IREL AND
F igur e 3.2 TABLE 3.12
FO RECA ST C HA NGE IN HOU SEHOLD COMPOS IT ION
Hou seho ld 198 1 1 9 9 0 2 0 0 0
Ssze 1 2 (Persons ) Census Low M d High 2 Low 2 Ms d High2
Not adjusted for unenumerated househo lds .
Low : average larger household size
High : average smaller household size .
- 32- TA BLE 3 . 13
IM PA CT OF CHA NG ING HO U SEHO LD SIZE COM PO S IT ION ON
DOM EST IC WAT ER CONSUM PT ION
3.2.5 Fo recasts
Fo recas ts of Dom estic Co nsump tion broken down by Div is io n are given
in Appendix 4 .
3 .3 NON -DOM E ST IC CONSUM PT ION FORECAS T S
3 .3 .1 Genera l
Futu re non-dom estic water co n sump tio n in th e Province h as be en
fo recast in line w ith p ro jected grow th in ap p rop riate activ ity va riables .
In all cases common assump tio ns have be en emp loyed fo r all wa ter supp ly
su b-d iv is io ns . The app roach a dop ted for ea ch ca te go ry o f con sumer is
ou t lined be low . Fu rt her de ta il co n cern ing un de rly in g assump tio ns is
contained in Append ix 5.
3 .3 .2 A gricu ltu re
Fo recas t wate r consum p t io n by agricu ltural con su m ers has been
p ro je c ted to grow in line w ith liv esto ck numbe rs in th e Prov ince . The p ro je cted ch anges in livestock numbe rs hav e been weigh ted by estima tes of
wa ter consum ption ba sed on design standa rds fo r agr ic u ltu ra l bu ild ings to
prov id e ove ra ll water consump tio n p roje ctio n fac to rs (shown in Ta b le 3 . 14 ).
-33- T AB LE 3 .14
The impac t of ch ange s in techniques of fa rm husb andry has no t bee n in c lu ded in th ese fo re ca sts and it is d if ficu lt to ass ess th e direct ion o f th is effe ct . It is un like ly that th is w ill ha ve a sign ifica nt im pact on to tal agr icu lt u ral dema nd .
3 .3 .3 Industria l Con sum t io n
Industria l co nsumpt io n h as be en p ro jected to gro w in dire ct p ro po rtion w ith industr ia l o utp ut . Th is imp lies an ove rall u nit e lastic ity o f water dema nd w it h resp ec t to indust ria l outpu t . A s note d in App end ix 6 such evid ence as ex ists con cern in g dema nd e last ic it ies sugge sts that a low er figu re mi gh t be app ro p ria te . These pro je ct ions shotild the refo re be re ga rd ed as sett ing an upp er bo u nd for indu stria l con sumption grow th assum in g the gr ow th in ou tp ut show n in Append ix 5 .
The approach does no t take accou nt of d iffe ren ces betw een sector g row th rates or of te chno lo gica l change bo th o f wh ic h may ha ve a s ig n ificant imp act on grow th in w ater con sum pt ion . It has not p rov ed poss ib le to assess wa te r co n sump tio n/activ ity re latio nsh ips fo r ind iv id ua l indu stry sectors in th e Pro v in ce . This mi ght be fac il itated in fu tu re by the rec lass ificatio n o f indu stria l consumers by na rro w e r cate go rie s in
Wa te r Charges B ranch reco rd s .
A disa gg re ga te d ap p ro a ch , ba sed on fo re ca st ing consump t ion by na rrow er indu s try sec tors , w ou ld however requ ire relia b le fo recasts of industry secto r grow th ra te s . Such forecas ts are gene ra lly ex tre me ly u nce rtain be yo nd the sho rt to med ium term . In p rac t ice , the re fo re , the s imp le r app roach ad op ted fo r the present stu dy is a rea s onab le one for lon g-term fo re casting .
-34- Ana lysis of the sensit ivity of consumption to diffe rent rates of
industrial grow th has been covered by means of a range of econom ic grow th pro jections in these forecasts .
3.3 .4 Commerce
Consumption in th is sector has been pro jected to grow in direct
p rop ortion w ith fo recast emp loym ent in private sector serv ice industry . This is base d .on the view that employm ent rather than output is likely to
determ ine consumption .
3.3 .5 Construction
Consumption has bee n pro jec ted to grow in line with forecast output in th is sector .
3.3.6 Other (Pub lic Services )
On the same basis adopted for private sector services , o the r (ma in ly pu bl ic serv ice s ) consumption has been p ro jected to grow in direct p ropo rtion with forecast employment in this sector .
3.3 .7 Agricu ltu ra l Domest ic Usa e
This has been pro jected in line w ith growth in avera ge consumption per cap ita as ind ica ted in Tab le 3.5 above . The growth in th is category of usa ge is lower than growth in overa ll domest ic consumption because it doe s not inc lude the element of increa se due to popu lation growth . It has be en assumed that the re will be no growth in the tota l population in agricu ltu ral househo lds .
3.3.8 Opera tional Usage
Op era tiona l usage has been estim at ed as approximate ly 3% o f tota l p ro duction . For fo recasting purpo ses it has been assum ed that th is wi ll grow in line with the tota l of dom estic and non-dom estic dem and .
-35- 3.3.9 Ad 'ustment fo r Unde r-re istration of Meters
Th is is shown in the p rojections as a co nstant 10% of total metered
'consumption . In practice it is hop ed that imp rovements in mete r accuracy
should lead to a redu ction in the unmete red quant ity although th is would
not affect overa ll consump t ion levels .
3.4 OVERALL CONSUMPT ION FO RECASTS
Summa ry foreca sts of consump tion broken down by Division are shown in Table 3.15. A mo re de ta iled breakdown of the forecasts by Div ision and by
category of consumption is given in Appen dix i•s Table A4 .2.
TAB LE 3 .15
SUMMARY WATER CONSUMPT ION FORECA ST S
-36- 3 .4.1 Comm en ts
Overa ll forecast consumption grow th in the Province varies from
2 .2% per annum on the high pro jection to 0.7% on the low projection w ith a m id pro jec tion of 1.3% pe r annum . The range of forecasts imp lies increases
in to tal consumption by the year 2000 of betw een 14% and 50% of estimated
tota l consumption in 198 1.
Dom estic consumption is the main component of growth , increasing from an estimated 5 1% of total ba se year consump tion to 57% of total consumption in 2000 on the high pro jection . On the low pro jec tion domest ic consumption growth is re lative ly more mode rate , rising to 55 % of the pro jected tota l by the year 2000 .
The consum pt iOn grow th rates pro jected for Northe rn Ire land ma y be comp ared w ith the growth in total p roduction exp ected by the Engl ish Water
Authorities as reported by the Nat ional Water Coun cil .
Water Au thorities in Northern Ireland
En gland and Wa les Pro jections
1980 - 2000 198 1 - 2000 % p .a . comp ound % p .a . compound grow th in p roduction g rowth in consumption
The re is evidently a fair ly close correspondence between the Northern Ire land pro jection s emanating from this study and the range of pro ject ion s reported for the RWAs . Howeve r , it sho uld be no ted that the RWA figures refer to tota l product ion , wherea s the N I figu res are for consumption only and these are not entirely comparab le .
3 .5 ELA ST ICITY OF DEMA ND
A discussion of the elastic ity of wate r demand w ith resp ect to changes in p rice and income is contained in App end ix 6 .
-37-- CHAPTER 4
UNACCOUNTED FOR WAT ER
4.1 GENERR L
Unaccounted For Water (UFW ) comp rises the difference be tween
measu red trea ted water product ion and identified consumpt ion . Records of production are ava ilable and deta iled assessments have been made of
consumpt i on for the base year as described in Chapte r 3. Thus it is po ssib le to estimate the tota l UFW on the basis of the se data . The
p rincipal origin o f UFW is lea ka ge from the pipe network and the direct measu rement of this using bulk me ters and waste wate r meter ins tallations
has also been ca rried out . Not su rprisin gly the two ap proaches yie ld
diffe rent resu lts , pa rtly on accoun t of inaccuracy of me ter readings but
a lso because some eleme nts of consumpt i on and/or leakage cannot be
correctly identifie d . Rece nt wo rk has resulted in re f i nement of con clusions rega rding consumpt i on, as discussed in Chapter 3 . This .chapter summa rizes the leakage assessments and p resents balances for water p rodu ction , consumpt i on and leakage .
4 2 LEAKAGE IN SUPPLY SYSTEMS
M inimum night flows in distribution sys tems are availab le from either dis trict m eters or wastew ater m ete rs for over 80% of th e Prov ince by
supp ly . Fo r other areas it was necessary to est imate ni ght flows from m ea su red re sults for similar a reas . Leakage rates have been calcu lated
from mi nim um night flow data by deducting legitima te night flows based on
trade m eter readings and an allowance o f 2 l/h pe r p roperty . An eq uiva lent
day of 20 hours has been used to allow fo r diu rnal pressure variations . Leakage in supp ly systems is d iscussed in detail in Vo lum e 2 .
Wastewater mete rs do no t cover the large r pipe line s particula rly trunk mains in large urban areas . Thus it has be en po ssible tm ly to
-38- est imate losse s from trunk ma ins , and the following factors , based on WRC
Techn ica l Rep ort TR 154 , have been used :-
Newer ma ins 500 1/km /h O lder m ains 750 1/km/ h
The est imate s of leakage rates are given in Tab le 4.1.
4 .3 WAT ER BA LA NC ES
As indicated above , data are available fo r
- treated water p rodu ction - est ima ted wa ter consumption - mea su red leakage
- est imated trunk ma in leakage
A summ ary of these data is p resented in Table 4 .2.
In v iew of the uncertaintie s in the estim ates of trunk main lea kage only the lea kage rates in distribu tion sy stem s have be en use d in the assessment of these balan ces . The tab le indicates that there are discrepanc ies between treated water p roduct ion and the totals of consumptive use and leakage , and these d isc repancies are ind icated in Tab le 4 .2 as balances . Positive balances ind ica te tha t either or bo th of consumption or leaka ge are under-estima te d . Ne gativ e balances indicate the rev erse .
The se co nclus ions are , of cour se , sub jec t to errors, one of which is me ter error . Rev iews of me ter accuracy have be en made recen tly in the Eastern Div isio n from which it wa s conc luded th at
(a ) Product ion meters are reasonably accu rate (i .e . within a few per cent )
(b ) Trade Meters tend to under-record and allowance for this has been made in the assessm ent of metered con sump tion ma de in th is study .
-39- (c ) Wastewater me ters are of low accu racy , bu t without pa rt icular bias .
In add ition , many of the consumption and leaka ge estimates are of
nece ssity ba sed on ex trapo lation from limited data , and are the refo re not o f a very h igh order of accuracy . Conseq uently the sma ller balances shou ld
no t be regard ed as ve ry much more than the results of the un ce rtainties in the estim ation o f the various comp onents .
It is ev ide nt that furth er detailed work is needed to obtain a bett er understanding of the reasons for the larger ba lances .
4 .4 NIGHT FLOW S IN BELFAST
In the cou rse • of the study , a five week sequence of hourly flows recorded by the Be lfast te lem etry sy stem during May 1983, was studied in an attemp t to measure the m inimum nigh t flow s in relatio n to the average daily
flow and the reco rded wastewater meter flows in the re levant areas .
The minimum rese rvoir outflow s (which did not oc cur sim ultaneously fo r all meters ) tota lled 135 MI/d which was abou t 64% of the average daily
flow for the area in 1983 o f 2 11 MI/d . The tota l of the relevant waste meter read ings was 84 M l/d .
The difference between the mi nimum reservo ir out flows and the wa ste meter flows , gives an indication of the consump tion by larger consum ers with direct connection to the trunk mains plus a measu re of trun k ma in leaka ge . Both factors shou ld be taken into ac count when assign ing priorities for sea rching for any trunk ma in leakage .
It is recommended th at th is exerc ise shou ld be rep eated at approp riate Interva ls making use of the latest addition s to the telemetry system .
-40- TABLE 4 .1
LEAKAGE RA TES
Distribution (1) Trunk (2) Tota l
Sub-d ivis ion System Mains Ml/d Ml/d M l/d
Be lfast 65 .2 4 .7 69 .9
Downpatrick 33 .0 1.0 34 .0 Lisbu rn 10.6 0.5 11. 11
Easte rn Div ision 108 .8 6 .2 115 .0
Antrim 12.9 1.3 14 .2 Ba llymena 18 .0 1.5 19 .5 Co lera ine 16 .4 1.4 17 .8
Northern Div is ion 47 .3 4 .2 5 1.5
Arma gh 15.0 1.4 16 .4 C ra igavon 11.3 1.7 13.0
New ry 12.3 1.8 19 .1
Southern Div is ion 43.6 4.9 48 .5
Enn isk illen 12 .6 1.1 13.7 Londonderry 23 .0 2.1 25 .1
Oma gh 14 .7 1.1 15.8
W estern Div ison 50 .3 4 .3 54 .6
(1) Ba sed on metering (2 ) Estimate s on ly
-4 1- •
TABLE 4 .2
WATER BALA NCES
Rates in Ml/d
(1) (2) (3 ) (4 ) (5) Division Sub Div is ion To tal Es timate d Leakage " Ba lance
Product ion Consum tion
EA STERN Belfast 220 .8 • 113.4 65.2 +4 2.2
Downp atrick 59 .8 32.2 33.0 -5.4
Lisburn 26 .6 21.1 10.6 -5.1
307 .1 166.7 108.8 +3 1.6
NORTHERN Antrim 36 .6 20 .0 12.9 +3 .7 Ba llymena 39 .2 28.9 18.0 -7.7
Co leraine 38.0 25.2 16.4 -3 .6
113.9 74.2 47 .3 -7.6
SOUT HERN Armagh 33 .3 2 1.0 15.0 -2.7
Craigavon 42 .8 26.8 11.3 +4.7
New ry 42 .3 24 .9 17.3 +0.1
118 .4 72 .6 43.6 +2.2
WEST ERN Enniskil len 24 .8 14.6 12.6 -2.4
Londonde rry 56 .7 27.3 23.0 +6.4
Omagh 25 .1 18 .4 14.7 -8.0
106 .5 60.4 50.3 -4 .2
TOTAL 645.9 373 .9 250 .0 +22.0
• Co rrected Distribution system leakage on ly - see Tab le 4 .1. Figu res do not add due to rounding . -42- 4.5 FUT URE LEVELS OF UFW
Wh ile it has been possible to quantify factors wh ich can be used for pro ject ions of consumption it is mo re dif ficu lt to assess the likely
changes in UFW . The mo st relevant data are the trends in water production ov er recent years . For the period 1973- 1983 the trends of annual increase s in average da ily product ion for the D iv isions are as fo llows :-
Eastern 2 .0% (1)
No rthern 3 .5% Sou thern 3.7% West ern 3.7%
Note (1) E ffects of the clos ing of Courtaulds factory al lowed for . The lower va lue for the Ea stern Div ision is in pa rt due to the imp lementation since 1976 of mo re effective waste con trol.
In view of the proportions of curren t UFW given earlier in thia chap ter and ident ified trends in consump tion , it is evident that these ch anges were not due to increased consumption alone . Thus it must be expec ted that if UFW is unchecked it w ill co nt inue to rise and w ill of cou rse be influenced by tbe rate of occurrence of leaks , which is unlikely to d imi nish . For want of better data , it is reasonable to as sume fo r p lann in g pu rpo ses that the 'underlying rate of increase in UFW will be equa l to the p rojected ra te of increase in legitimate consump tion in the absen ce o f mo re effective me asure's for the leakage contro l .
-43- CHAPTER 5
REDUCT ION OF LEAKAGE
5.1 INT RODUCT ION
One of the principa l conc lusions of this study is that the leve ls of unaccounted for water (UFW ), including me asur ed leakage , are higher than is desirab le . Wh ile acknow led ging that these assessm ents are not precise it is clear th at a significant contribution to the effic iency of water supp ly
system s in No rthern Ire land wou ld result from the redu ction of leakage .
The p rob lems of leakage have been subject to detailed investigation in the UK w ater industry , pa rticu larly in the pa st dec ade, and recommended
control p rocedu res have been established . These are describe d in the Nationa l Wate r Coun cil Standing Technical Commi ttee Rep ort No . 26 (1980 ) to which ex tensive refe rence h as been ma de in this report . The general approa ch , wh ich is equally app rop riate in No rth Irela nd , is to follow a logical sequence , as follows :-
(i ) mea su re the ma gnitude of leakage in the system .
(ii ) assess the cost that can be attached to leakage .
(iii ) est im ate the resources needed and costs arising from relevant leakage cont rol programmes .
(iv ) eva luate the most econom ical p lan for leakage oontrol .
(v ) p rovide the ne cessary resources and imp lem ent the leaka ge
contro l plan in order to assess the magn itudes and locations of lea ks .
(vi ) rep air leaka ge s as necessary .
(vii ) monitor p erfo rmance at regular inte rvals .
-4 4- The Department has already taken some action along these lines for
Be lfast and a report on the Belfast Sub-Division Waste Detect ion Scheme Leaka ge Ana lysis was prepared joint ly by Kirk McC lure and Morton , McAdam Design and Fe rguson Mc Ilveen , in September 198 3. A w ider app raisal has be en ma de in the present stu dy , covering the who le of Northern Ire land . The cu rrent (198 1) levels of m easured leakage are disc ussed in deta il in
Vo lume 2, and are summa rise d in Chap ter 4 of this rep ort . The present chapter co ns iders the extent to wh ich m ea sured leakage in dis tribution systems can be reduced , the associa ted costs and benefits and also indica tes the resources requ ired to en sure that the control of leakage is mainta ined .
In view of the ma gnitude of the other elem ents of UFW in Belfast (i .e . trunk main losses and 'ba lance ') it is necessa ry that it shou ld be investigated further . Prelim inary work referred to in Section 4 .4 suggested that a ma jor component ma y be unidentified leakage and further wo rk is needed to establish its real comp onents . Th is work sho uld be ca rried out in a similar ma nner to the leakage contro l referred to above , invo lv ing :
a . asse ssment of availab le info rma tion , b . p reliminary tests on trunk mains and/or reservoirs , c . p reparation of a p ro gramme of inves tigation , d . asse ssm ent of the likely costs of such work and the be ne fits of the
resu lting UFW reduction , e . p rovision of the ne cessary resources , f . imp lementation of investigations to detect and locate lea kages , g . repair as necessary .
However , the init ia l approach should be to give priority to the reduction of ident ified leakage for which costs can be estim ated .
5.2 LEAKAG E LEVELS
Repo rt No . 26 gives a me thod fo r predicting redu ctions in likely net night flows for various methods of leaka ge contro l. The prov ision of w aste metering throughout Northern Ireland is now being imp lemented and this
-45- method of leakage contro l has been assum ed for assessing future net night
flow s . Leaka ge rates are assessed in te rm s o f litres per property per ho ur and to ta l leakage depends on the property counts in each area .
Atta inab le target leaka ge lev els have be en assessed broad ly in acco rdance with the recommendations of Repo rt No . 26 , modifie d as app ropriate in the light of local exper ience and knowledge . These levels are sign ificantly grea te r than those wh ich wo u ld be predicted strictly in ac co rdance w ith that rep ort , but rep resent atta inab le short term ob jectives .
Net night flow s for the base year and target leakage levels for each of the major supp ly systems a re set out in Tab le 5.1.
TABLE 5 .1
NET .N IGHT FLOW S
Net Night Flow
(l/prop/h r )
N o . of Prop ert ies 198 1 Target
Eas te rn Div is ion 253 409 23
Northern Div ision
Co lera ine/ Ba llym oney/Moy le 27 548 32 17 Ma gherafe lt/Coo kstown 16 8 58 30 17 Ballymena/An trim/La rne 43 227 25 13
Southern Div is ion 79 889 29 16
-46- 5 .3 COSTS OF LEAKAGE
5 .3 .1 Method
The gene ra l app roach is to assess the cost of leakage , and the sav ings brought about by its reduction , using unit co sts of leakage based
on tw o distinct elements ,
(a) reduction in annua l op erating costs , and
(b ) de ferment of capita l expend iture on schem es that wou ld be requ ired to increa se water p roduction .
5 .3.2 Un it 0 eratin Cost
The reduction in annua l ope rating costs consists of two ma jor
e leme nts, the reduct ion in electr icity ch arges for pump ing and the
reduction in the quantitie s of chem icals used for treatment . The ope ratin g
co sts for the ma in sou rces have be en obtained fram each of th e Div isions .
It is assum ed that the cheaper sou rces would be used as much as possib le and the unit operating costs have therefo re been tak en as tho se of the mo st expe nsive sources .
,Calcu lat ions of the un it operating costs of leakage for the ma jor
supp ly systems for the base year 198 1 are included in Appendix 5.
5 .3 .3 Unit Cap ital Cost
The unit cap ita l costs of leakage for the ma jo r supp ly systems are based on the deferme nt of cap ital expend itu re on schem es which wou ld be
requ ired to satisfy futu re demands . The estima ted co sts of the schem es have been d iscounted to the base year of 198 1 at the cu rrent required rate of re tu rn of 5% . In certa in of the supp ly systems the existin g yields of
the sou rces are adequate to meet the demands until the end of the century and the un it capita l co st of leaka ge is therefo re negligible .
The ma jor systems for wh ich capita l costs of leakage have been
-47- assessed are described below .
Ea ste rn Div ision - Developm ent of new up land sources .
Northern Division
1 (a ) Co leraine/Ba llymoney/Moy le - Interco nnection of the Ballinree s and Altnahinch sources w ith a p ipe line from Ba llinrees T rea tment Works to G len lough Re se rvo ir .
(b ) Maghe rafelt/Cookstown - The reliable y ie lds of the sources shou ld be adequate until at least the end of the century . Therefore , no new scheme is proposed .
(c ) Ba llymena/Antrim/Larne - Cons truction of the Inver Dam and 1 extens ion of th e treatm ent plan t . Southern Div ision - Deve lopm ent of the Cam lou gh Source
and exte nsions of distribut ion from Castor Bay .
Western Divison 1 (a ) Londonde rry/ Limavady - Improvements to Altnaheglish Reservo ir to ach ieve the original yie ld .
1 (b ) St raba ne/Oma gh - Fo llowing the completion of cu rrent extensions to sou rces , the reliab le 1 y ields shou ld be adeq uate until at least the end of the centu ry . Therefo re no new scheme is
p ropo sed .
1 (c ) Fermana gh - The extension o f Killy hev lin 1 T reatment Works . -48- Wh ilst the wo rks described above may no t nece ssarily be tho se wo rks
that are ev entually carried out , it is expe cted that works of a simi lar
nature , and having much the same disco unted cap ital cost , would be required
to meet future dema nds .
Calcu lations o f unit cap ital costs of leakage for a rate of growt h in demand of 1% are included in App endix 7 . Th is rate app rox ima tes to the
mid level consumption forecasts (see Ch ap tei 3 ).
5.3 .4 An nual Costs of Le aka e
The annua l cost of leakage is calcu lated using the formu la :-
Ann ual Cost of Leakage NNF x 20 x 365 x C
(l/p rop erty/year ) 100,000
where NNF is the net night flow in litres per prope rty per hour and C
is the unit cost of leakage in pe nce pe r cub ic metre (see Appe nd ix 7 ). 20 hours each day are used in place of 24 hours to allow for the effect of
pressu re variation . Th is formula app lies to both current and target leakage rates .
The resu ltin g annua l costs are set out in Ta ble 5.2.
5.4 COST OF LEAKAGE CONTROL
Th e effo rt req uired to ensure effect ive leakage cont ro l is sub stantia l, and it is esse ntial that in futu re the necessa ry resources are
con tinuously provided it target leakage levels are to be ach ieved and maintained .
By 198 1 p re lim inary sta ges of act ive waste control had been
imp lem ented only in Easte rn Div ision and the a nnual cost of leakage control
in the other Divisions wa s effectively ni l . Th e cost of leakage contro l in
Eastern Div ision for that year can be ca lculated using informat ion contained in the Div ision 's 198 1 annua l repo rt . From this the detection element of waste co ntrol for the Division is e stimated to be £ 114 000 .
-49- 11111 fl • 11111• a l IS 11111111 fl 111• 11 11• 111 M I IMO M I • M O
TAB LE 5.2
A NNUAL C OSTS OF LEAKA GE
No . o f Un it Co st Cur re n t (198 1) Le ve ls Targe t Leve ls Su pp ly Sy stem P rop erties o f Leakage
NNF Tota l Annua l NN F To ta l Annual
Cost o f Leakage C o st o f Leakage l/p/h E p/m3 _ 1 / p / h _E
1 til Eastern Division 0 253 ,4 09 7 .6 23 3 ,234 ,000 13 1,828 ,0 00 I C o lera in e/Ba l lym oney/Moy le 27 ,548 5 .5 32 354 ,000 17 188 ,000 Ba llymena/An trim/ L orne 43 ,227 5.6 25 442 ,000 13 2 30 ,0 00 Ma gh era fe lt/Cooks to wn 16 ,8 58 4 .7 30 174 ,000 17 98 ,00 0 No rth e rn D iv is ion 87 ,6 33 970 ,000 5 16 ,000
Sou thern Div is io n 79 ,889 7 .7 29 1,302 ,000 16 7 18 ,0 00 Londo nderry / Lima vady 30 ,6 20 4 .5 40 402 ,000 17 17 1,000 Strabane/Omagh 2 1,7 15 3.9 36 223 ,000 19 117 ,000 Fe rman a gh 17 ,068 5 .3 39 2 58 ,0 00 22 145 ,000 Weste rn D iv is io n 69 ,453 883 ,000 4 33 ,0 00 For the futu re , the practices recomme nded in NW C Repo rt No . 26 should be fo llowed and the co sts of the requ ired inspe ction , testing and
monito ring wo rk are discussed in deta il in Appe ndix 8 . The total annual
costs of ach iev ing the target leakage levels for each Division are summa rised in Tab le 5 .3.
TABLE 5 .3
ANNUAL CO STS OF LEAKAGE CONTROL
Divis ion Annu al Cost
E Easte rn 298 000
No rthe rn 111 000
Sou thern 10 1 000 Weste rn 104 000
6 14 000
5 .5 COST OF REPA IRS
The rate of occu rrence of new leaks in a pip e network will rema in
sub stantially constant, follow ing the int roduction of a new leakage contro l policy , since none of the factors affect ing it will have changed . Thus the
cost of rep airing leaks, w ill also be sub stant ia lly constant and can be ignored in compa rative assessment s , provided leaka ge is ident ified speed ily . How ev er , where there are arrea rs of rep air work to be ma de up , wh ich can on ly be carried out after mo re intensive leakage detection has
been imp lem ented ; the cost of tho se arrears shou ld be allow ed for .
For the pu rp ose of this study it has been assumed th at the oost of rep airing the arrears would be amortized using a payback pe riod of 20 years
at an interest rate of 5% per annum . It is not po ssib le to make accurate estimat es of tota l cost of these repairs , but the annual amounts are not
great in relation to other oosts .
The annua l charges are estimated to be £ 40 000 for the Eastern Div ision and £ 16 000 for each of the other Div isions and have to be added to the cost of leaka ge contro l . They rep resent a total expend itu re of abo ut £ 1.1 m illion sp read over a pe riod o f 3 to 4 years, i.e . abo ut £ 3 15 000 p er annum . -51- 5 .6 ANNUAL BENEFITS
Th e annua l costs of leakage and leakage contro l for the base year and for the ta rget leakage levels for each of the Divisions, together with the annu al sav ings in cost are summarised in Table 5.4 . This table also shows the annual sav ings in water wh ich wou ld result if the target levels were atta ined .
The conclusions to be drawn from this table ar e :
(a) The total net gain to the Depa rtment re sulting fram an active and
effective leakage control po lic'y wo uld be of the order of £ 2.3 m illion ann ua lly .
(b ) In ord er to ach ieve these sav ings the nece ssa ry resources mus t be
increased requir ing the total exp end iture of an estimated £ 929 ,000
pe r annum . Th is amount cov ers the to ta l resources requ ired for
leakage detection together with the sta ff emp loy ed on the repa ir o f
the backlog of leakages . Some of this expenditure is alrea dy bein g
incurred by the Wat er Service in ex isting leakage reduc tion
pro grammes .
(c) The po tentia l total sav ings of water due to reduction of measured leaka ge in the distr ibution network is about 120 Mild .
5 .7 PRACT ICAL ASPECT S
In No rthe rn Ireland present leakage levels are be tween 23 and 40
1/p/h . In En gla nd target leakage levels are gen era lly fixe d in accordan ce with NWC Report No . 26 , but original leaka ge leve ls are much lowe r and in general prope rty den sities are higher th an in Northern Ireland . Tb take accoun t of these and other factors target levels fo r Northe rn Ireland have be en assessed conse rvatively in the range 13 to 22 1/p/h . The target levels could we ll be im proved upon as they rep resent practicab le rather th an ultima tely obta inable figures in the Northern Ireland context .
-52- 5.8 RESOURCES FOR LEA/CAGE CONT ROL
Es timates have been made of the long-te rm resources requ ired to provide effect ive act ive leaka ge co ntrol, based on manpower requirements , etc . tha t have been exp erienced in Northern Ire land in this wo rk .
The resources required are the eq uivalent of 68 industrial and supe rvisory staff workin g on the monitoring and detect ion of leakage . In acco rdance w ith the recommendations of NW C Report No . 26 , th ese allocations do not inc lude the resources required to repair leaks . At p re sent approximate ly 64 fu ll time equivalent sta ff are emp loy ed on leakage detection and repair . About 42 of these are employed on leakage detect ion activ ities . Thus there is a requirement for an addit ional 26 pe rma nent staff for leakage detect ion wo rk over and above the present complem ent .
Mo re intensive effort on leakage control wou ld result in a tempo rary back log of leakage repa irs . Prelimi nary estimates ind icate that an add itiona l 25 staff wou ld be required for a pe riod of three or four years to reduce this backlog and the estimates of oost of the addit ional staff have been inc luded in the costs of leakage control . Th erefore , in the init ial stages the total numbe r of staff that would be directly involved on lea ka ge control would be of the order of 93 pe rsons, not including about 22 sta ff cur rently emp loyed in leakage repa ir work .
In order for leaka ge co ntro l to be effective , it is essential that the furthe r resources set out above are made ava ilab le , both for the long term contro l p rogrammes and in the shorter term to attend to th e backlog of leakages .
In addit ion to the staff requirem ents outlined , the Water Serv ice has ident ified a need for 10 extra staff , m ainly for data co llection work .
-53- • M I • IS U M UM M O M • N M M OM N M I • 11 M OM M I IS S O
TAB LE. 5.4
A NNUAL B ENEF IT S
B ase Year (198 1) Co nd itio ns Leaka e Co nt ro l T a r ets
D iv is ion Annu a l C ost A nn ua l Cost Tota l Ann ua l C ost Ann ua l Co st * Tota l Sa vin g in Sa vin g In
of Leak a ge o f Leakage o f Le aka ge o f L eaka ge Cost Wa ter
C Ontro l Con tro l
E. 4 4 4 E 4 4 M l/d
Eas te rn 3,234 ,000 114 ,000 3,348 ,0 00 1,8 28 ,000 338 ,000 2 , 166 ,000 1, 182 ,000 5 1
North e rn 9 70 ,0 00 97 0,000 5 16 ,0 00 127 ,000 643 ,000 327 ,0 00 23
Southe rn 1,302 ,000 1,302 ,000 7 18 ,000 117 ,000 835 ,000 467 ,000 2 1
W este rn 88 3 ,0 00 u 88 3 ,000 4 33 ,000 120 ,0 00 553 ,0 00 330 ,0 00 27
TOTA LS 114 ,000 7 02 ,000 2 ,306 ,0 00 122
Inc ludes an equivalent annual co st of £ 88 ,00 0 for staff required for the repair of back log of leakages . The
actua l exp end itu re for such staff dur ing the first 3 to 4 y ears will amount to about £ 3 15,000 pe r annum , giving a
total of a bo u t £ 9 2 9 ,00 0 for ea ch o f tho se y ea r s . 5 .9 RECOMMENDAT IONS
In view of the conclusions regard ing the bene fits of leaka ge reduction it is c lear that the necessary p rogramm es shou ld be p rep ared and executed . We the re fore recomm end that a dete rmi ned and sustained drive to redu ce leakage shou ld be initiated and pu rsued as a matter of the h ighest p riority and impo rtance . To th is end it is vit al that ,
(a ) the necessary financ ial resources should be ma de available .
(b ) staff wo rkin g on leakage control should be rev iewed , their numbe rs
brou ght up to the .levels requ ired and su itab le t raining provided .
(c ) leakage contro l programmes as out lined in this report should be
p lanned and execu ted .
(d ) effe ct ive leakage con tro l shou ld form pa rt of the regular rou tine of op erational work in order to maintain satisfac to ry con trol.
(e ) monitori ng of leakage rat es should be kept clo se ly under rev iew .
-55- CHAPTER 6
PLANNING CRITERIA FOR WAT ER SUPPLY
6 .1 INTRODUCT ION
The te rm s of reference for th is study require th at a strategy should be develope d for cost effective ma nagement of the water supp ly/dema nd ba lance to the yea r 2000. Th ey al so call for conclu sions to be drawn about the need for a new source to serv e the Eastern Area of the Province . Th us
a long te rm plan is required , cove ring the next 15 to 20 yea rs wh ich id ent ifies water req uirements du ring th is pe riod and o ffers an effective
and economical app roach to meetin g them .
The timing of the introduct ion of new sources depends not only on the rate at which dema nd increases but also upon the suc ce ss of dema nd
management po licies (leakage reduction , effects of water regu lation s , public awareness , etc .) and th is chapter exami nes these and other factors
wh ich affect the planning of wat er supp ly developmen ts .
6 .2 TREATED WATER REQU IREMENTS
A bas ic ob jective of wate r supply p lanning is that , sub ject to certa in considerations wh ich are d iscussed lat er in th is chap ter , all
future treated water requirem ents should be met . For this pu rpo se fo recasts have been made of futu re consumption levels as described in
Chapter 3. However , the total requ irem ents comp rise both actual consumption an d UFW . Un less UFW is contro lled it will contin ue to grow and in Chap ter 4 it was suggested that it wa s reasonab le to expect that its uncontrolled grow th rate wou ld be similar to that for consump tion . Thus forecasts of tota l t reated wa ter requirements including UFW to the year
20 00 have be en made on th is b as is for each Div ision , using the high , m id and low rates of growt h discu ssed in Chapter 3 . These are shown in Figure s
6 .1, 6.2, 6 .3 an d 6 .4 on wh ich the recorded production figures from 1975 to 1983 and the currently available wate r sources wh ich were described in
Section 2.3 .are also p lotted . Th ese diagram s are based on the assumpt ion
-56- 500
TOTAL REOUIREMENTTS
400 AVA I LABLE SOURCES thssø 5 % LOW OPERATING MARGIN
300
i 200 • I DENiTIF IED CONSUMPTION 0 R- C-) 0 0 CC ce Lu
100 al 2 0 0 < .": CY 111 > <
ti l 17.
1975 1980 1985 1990 1995 2000
PRODUCTION FORECASTS WITHOUT LEAKAGE REDUCTION EASTERN DIVISION Figure 6:1 300
•:3 200 AVAILABLE SOURCES r-: c.) fl fl TOTAL S% REQUIREMENTS CC OPERATING MARGIN *O M L ' 0- 0 ui-cp Lij 10 0 -‹ 0 2 4 a l IDENTIFIED cc o_,Lu CONSUMPTION
IC
1975 1980 1985 1990 1995 2d00
PRODUCTION FORECA ST S WITHOUT LEAKAGE REDUCTION NORTHERN DIVISION Figure 6.2 300
--X 200
0 AVAILABLE SOURCES tk\e‘A TOTAL 0 REQUIRE MENTS 0 tAv oll /t4 CC 5 % OPERATI G a. LOW cc MARGIN s-Li i
ILI t u LIa 100 - Z IDENTIFIED W CC 0 Il i •CONSUMPTION ILI
1975 1980 1985 1990 1995 2000
PRODUCTION FORECASTS WITHOUT LEAKAGE REDUCTION SOUTHERN DIVISION Figure 6.3 300
.10 X 200
AVAILABLE SOURCES 0 CC O. 5 °A, MEDIUM TOTAL OPERATING REQUIREMENTS CC Lu MARGIN
100 0 Lu ww
E5 Z 4 IDENTIF IED 0 •ZC CONSUM PTION
1975 1980 1985 1993 1995 2000
PRODUCTION FORECASTS WITHOUT LEAKAGE REDUCTION WESTERN DIVISION Figure 6.4 that with in each Div is ion there are no restr ictions in transf.erring
supp lies from a ll sources to consum ers. How ever, O w i n g to the lim itat ions o f the systems , th is ma y no t be poss ible in al l cases .
6 .3 OUT PUT FROM SO URCES
In assessing the effective capa cities of sources it is necessa ry to ma ke a llow ances for several requi rements over an d above treated water p roduction . Th ese needs are discu ssed below and are allowed for in assessing the l imitations of exist ing and p ropo sed new sources .
6 .3 .1 Process Water
Supp lies are needed in treatment plants for washw ater, sand washing , etc . wh ich have to be provid ed from the source . For Lo ugh Neagh p lants this wate r is readily available , but for up land sou rces it must be deducted from re liab le yields.
6 .3.2 Com ensation Wate r
In some catchm ent s min imum compensation flows or p rescribe d flows must be ma intained and these must also be deducte d from the re liab le yie lds . Th ese qu an tit ies have been allowed for in the yields given in
Section 2.3 of th is repo rt .
6 .3.3 Ope rating Ma rgins
This study is add re ssed to the tim ing at wh ich new sources are needed, a matter influenced largely by the rate of incre ase of water demand . However it is necessa ry to introdu ce an operating mar gin into the equat ion between p ro jec ted demand and the y ields of available sou rces as a sa fety fac tor to allow for uncerta inties , on the dema nd side o f the equat ion , of the kinds d iscussed below .
(a ) Short term fluctuation s of demand . It is difficult to put a reliable
estimate on such fluctuat ions , but it is po ssible to consider va riat ions abou t the trend of total production in Eastern D ivis ion
-57- from available records . Th e general increa se in the annua l average
rate of w ater supp lied was about 1.5% per ann um from 1974 to 1982 and w ithin th is pe riod the max imum variation s were about 6% above the
gene ral t rend line in 1979 and about 6% be low it in 198 1. Events in
this pe riod inc luded the closing of a large textile fac tory , Cou rtaulds , and these changes shou ld therefore be regarded as
extreme .
(b ) Seasonal v ariation in water demand . Th ese are signif icant in many
UK water und ertak ings , where peak week ly averages commonly ex ceed annua l ave rages by over 10% , usua lly in the summer . Available month ly fi gu res for the Easte rn Div ision for 1974 to 1982 show that
month ly averages exceed annual averages by 3 to 6%. Peak months occur gene ra lly in the winter and are probab ly associated w ith the
increased inciden ce of pipe bu rsts that commonly occur in cold weather . Th ese particu lar pe ak variations are sma ll and te nd to
arise when up land reservoirs are filling and are therefore un likely
to be imp ortant . How ever , in years when w inter conditions are not so severe , summer peaks occur . These peaks are mo re evident at sub- d ivisio nal level and are part icularly imp ortant where supp lies are
take n from up land catchments in wh ich the reservoir capacities are limited . In such cases , if up land stora ge is a llocated to mee t pe aks , there cou ld be significant reductions in the volumes availab le
for balancing st ream flow and , consequent ly , in the reliab le y ields .
(c ) Emergency situations invo lving lo ss of wate r dow nstream of sou rce or treatment w orks . In gene ral such situations are short lived and ,
althou gh the water lost from the sy stem has to be made good , the total quantities involved are likely to be relatively small .
Wh ilst ma tters of the kind refe rred to above nee d to be taken into accou nt it would be unrealistic to expect a w ater undertaking to be ab le
to meet all short term flu ctua tion s in dem and without regard to the oosts invo lved . The crit ical period w ith which a study of th is kind is conce rned lies with in the pe riod of a few years when the basic projection of water dema nd lies c lose to the reliab le yie ld of the th en av ai lable resources .
Fluctuations of dema nd above the basic projection could then prese nt significant supp ly d ifficu lties and it has been considered pru dent to allow
58- a minimum ope rating margin of 5% o f water product ion (i .e. about 10% of identified current water consump tion ) to cover demand uncertainties in those crit ical years .
How ever, ope rating experience in pa rticu la r circumstances , such as those des cribed in (b ) above for ca tchments hav ing sma ll reservoirs , ma y ind icate that a rather larger margin should be adopted for some supp ly sys tems .
6 . 4 LEVE L OF SERVI CE TO CONSUME RS
The Impo sition of rota cuts is the only practicable po licy available to the Wate r Service in contro lling con sumption with v irtually imm ediate effects . Th e acceptab le frequency of such cuts should not, on average , be more often than once in twenty yea rs .
In Vo lume 2 of this repo rt the effects of imposing restriction s on the output of the Silent Va lley source a re d iscu ssed . These invo lve a 20% cut in sou rce output when the reservoir level reached 25% ful l . Th e conclusions indicate that the impo sition of rat ioning on the sca le env isaged does not in fact allow a sign ificant increa se in effect ive re liable yie ld of th is source above th e more conventiona l 1 in 50 year failure level. Fu rther , the order of accuracy of the figure is likely to exce ed th is increase and also the app lication of ratio ning ru les wou ld not be ve ry prec ise . It mu st the re fore be concluded that ration in g of this na tu re offers no real advantage in resou rce p lann ing fo r North ern Ireland and it is recomme nded tha t the slightly more con se rvat ive , and nn re conventional, reliable yie lds of sources based on 1 in 5 0 year failure shou ld be adopted for plann ing purposes .
Wh ile the above conclusions are based on Silent Va lley, where the re se rvo ir capacity is 4 4 % o f ARV , the effects of rationing in catchm ents having p rop ortiona lly much sma ller reservoir cap acities are lik ely to be more sign ificant . However , in these catchments the yields are inf luenced to a great er ex tent by the physical characteristics of the catchm ent and
-59- the estimates of yields are thus less reliable , ba sed as they are on
regiona l y ield/sto rage cu rve s . Thus it is consid ered th at the 1 in 50 year fa ilu re criterion shou ld be use d for all up land catchments .
Nev erthe less , the use o f ration ing rema ins in the armoury of dema nd
mana gem ent as pra ctised generally in the UK and is avai lable for use in the
more extreme drought conditions .
Th us the recommended level of service is th at the consumer shou ld
receive re liab le supp lies w ithin the current pa ttern of demand and that sign ificant reductions in supp ly shou ld no t be expe cted at frequencies
exceed ing on ce in fifty years .
The curre nt pa ttern of demand is , of course , influe nced by the type and quality of water fittings wh ich a re in use and by the extent of
own ership of app liances to those ab le to afford them . Future grow th in the use of such app liances has be en taken into acco unt in p reparin g the
estimates of water dema nd , but it has not been practicable to anticipa te the effects wh ich mi ght be p roduced by a rev ision of the current W ater
Regulations . These correspond to the Water Byelaws in GB and it is likely
that new Mode l Byelaws will become availab le du rin g 198 4. AB cu rren tly dra fted the Model looks to the more effective use of wa ter in such app aratus as WCs , u rinals and wash ing machines, but significant effects on
wate r consump t ion cou ld not be ant ic ipated for many years . Nevertheless , the immi nence of the new Mod el p rese nts long term opp ortu nities for influencihg the growth in water users ' legitima te dema nds .
6.5 LEAKAGE C ONT ROL
Wh ile consumer dema nd is expected to increase , the level of tot al water requirem ents in the next few yea rs w ill dep end to a large extent on
the succe ss ach ieved in leaka ge reduction . Thus for pla nning pu rpo ses it
is necessary to consider a range of op tions , both for consumption fo reca sts and UFW reduct ion . For the latt er the prim ary options are as follows :-
-60- (a ) In the wo rst case if the necessary resources to ma ke sign ificant
reductions in the p resent levels of leaka ge a re not prov ided to the Water Se rvice , the se w ill cont inue to incre ase in line w ith
consumption .
(b ) Leakage reductio n program mes in wastewater meter districts (i .e .
gene rally in distribut ion networks ) w ill achieve the ir target of 13
l/p/h as discusse d in Chapter 5. It is assumed that a pe riod of ten y ears wo uld be p ract icab le for this w ork . Thereafter leaka ge wou ld
be controlled at the target leakage levels .
(c ) Tota l UFW (where th is exceeds m easured leakage ) is reduced to
accep table levels . For practical pu rpo ses , on the basis that th is is
largely leakage , a .p rop ortiona l reduction equal to that for (b ) above wou ld appear to be a reasonable first app rox imat ion .
The sp ectrum of total w ater requ irements to be considered thu s comp rises a range of consumpt ion forecasts supe rimpo sed on a range of UFW
levels . Th is is illustrated in Fig . 6.5 which shows op tions (a ) and (b ) above for the whole of the Eastern Division , and , al lowing time for the recru itment and training of the necessary sta ff , assumes that effective leaka ge con tro l can be im plem ented in 1986 . Th is diagram must be taken as illustrative only , as the resu lts of leakage control w ork cannot be accurately fo re cast .
The bene fits of pressure reduction have been demonstrated in the report on Leakage Ana lysis dated Sep tember 1983 wh iCh co ncluded that som e
1.2 M l/d cou ld be saved in certain limi ted areas of Belfa st. Th is may offer further significant contribut ions to U FW reduction in other areas where it is shown to be practicab le .
6 .6 DEVE LO PM ENT PROGRAMME S
Th e nex t chap ter discusses the po ssib ilit ies for development of further sources and the evaluat ion of the mo st econom ical options . As indicated in ea rlie r sections of this chap ter it is not po ssible to fo recast w ith p re c ision the dates when new sources w ill be need ed ,
-6 1- 500
Likely earliest date of commissioning of a new sour ce
Unrestrained growth in poduction 400
0 9 \‘314
95% of available source yields
; .< " I' .. 0 -- — . . " — 300 . -- - - — I ..0 - - e s. IL a -;... 0 / Effect s of C achieving Y < target leakage L l - J rates & 13l/ p/ h a 10 YEAR PROGRAMME ui IT. 1= z ui o
200
100
NOTE Bolonce of UFW assumed t o increase in proport ion to consumption
1975 1980 1985 1990 1995 2000
POSSIBLE EFFECTS OF LEAKAGE REDUCTION PROGRAMMES EASTERN DIVISION Figure 6 . 5 p rima rily due to uncertainty regarding th e imp lementat ion of effective UFW
reduction pro gramme s . To overcome this p roblem , particularly for the
Easte rn Area , the approa ch adopted has been to determ ine opt imum strategies
for a range of demand grow th patterns. Th is isdescribed in more detail in Chap ter 7 .
In p lanning for development a most important factor wh ich mu st be bo rne in mi nd is the long lead time req uired to bring in a new source .
Exp erience has shown that it take s abou t seven to eight years to dea l with the various sta ges of investigat ion , design , p ub lic inquiry , tendering , construction , etc .
It has been demo nstrated that , give n adeq uate resources , there is good reason to ant icipate that significa nt leakage reduction can be ach ieved . If suc h reductions can , in fac t , be fl ecured they wou ld be high ly
cost effective and would de fer the need to introdu ce new sou rces for several years . It must be recogn ised , however , that leakage reductions may not be ach ieved e ither in the time scale , or in the physical quantities ,
ne ce ssary to enab le the introduction of new sou rces to be deferred . It is esse ntial therefo re that there should be an alt ernativ e, other than the
int roduct ion of water restrictions over a pe riod of severa l yea rs , wh ich can be taken up if leaka ge reduction is inadequate .
It is recomme nded that prepa rations should pro ce ed immediately , so as
to be concurrent w ith the leakage reduction m ea sures , for the
identification , design , and promo tion of new sour ces . Only by the early and vigorous imp lem entat ion of the conc lusions of the Septembe r 1983 rep ort
on Leakage Analysis in Belfast will the oppo rtun ity ar ise for secur ing , in the ne xt two or th ree years , suffic ient re sul ts to give reasonably reliab le
gu idan ce on the furthe r improvements that could be ach ieved and sustained
in the lon ger term . Du ring that two or three years p reparatory work on the optimum source development for the Ea ste rn Area ou ght to proceed to the ma ximum extent po ssible and th is would in clude outline design of the preferred sch em e and preparation of the documentation needed for a public
inquiry . Otherwise , in the eve nt of it being shown that leakage cannot be brough t un der adequate contro l in practice , consumers will be expo sed to the effects a rising from vital work p relimi nary to the promot ion of a new
source not hav ing been comp leted . In that event the introduction of
sustained water restrict ions w ill ne ed to be contemp la ted in the period be fore a new source can be approved and constru c ted .
-62- It is also necessa ry to consider the poss ib ility that adequate resources for effective leakage reduction will not become ava ilab le . In that case not on ly wou ld consumer demand increase but leakage lev els wou ld a lso continue to rise . The rate of growth of total p roduction requ irements is di fficult to assess but it is un likely to be less than that fo r ident ified consumption alone . In these circum stan ces it wou ld be essential for the necessary steps to be taken withou t de lay for the ear ly developmen t of a new source for the Eastern Area in order to mi nim ise the occu rrence of length y pe riods of restrictions of supp lie s . In addition to the p reliminary work referred to earlier , it wou ld be necessary to proceed to pub lic inquiry , deta iled design and construction of the required wo rks .
-6 3- CHAPT ER 7
APPRA ISAL OF PROJECTS
7 .1 INTRODUCT ION
The intention of this aspect of the repo rt is to ident ify the best new source of water for the Easte rn Ar ea and to study the cost effective-
ness of interconne ct ion of existing sources to provide savings in ope rating and cap ital co sts for the who le of Northern Ireland . Outside Eastern A rea ,
th e identification of new sou rces is not pa rt of this report but neverth e- less the alternative to interconnection of ex isting sources is usually th e
dev elopment of a new source (or augm entation of an ex isting one ). In gene ral such new sources have a lready be en identified by the Water Se rvice
and their consultants , in va rious feas ib ility studies and repo rts .
The conclusions of such studies and reports have been taken as valid . Wh ere these conc lusions have been va ried , it has generally been in the m atter of sca le rather than p hilosop hy .
The projects app rop riate for consideration in th is repo rt have p revious ly been identified and are discu ssed further in the fo llowing sections :-
7 .2 Eastern Div ision - New sou rce
7 .3 Ba llym ena/Antrim/ Larne - New source
7 .4 Co leraine/Ba llymoney/Moy le - Inte rconnect ion of Altnah inch and Ballin rees
7 .5 South Division - New source 7 .6 Strabane/Oma gh - Interconnection of Lough Fingrean with River
Derg. 7 .7 Ferma nagh - Interconnection of Ki llyhevlin with Altaveedan .
Work is un doubte dly requ ired in the Lo ndonderry/ Limavady area , to cope with the deterio rat ion of Altnah eglish dam , and is un de r consideration by other consultants : pend ing their rep ort , further comm ent ca nnot use fully be made . Likew ise an interconne ction pipeline in the Ma ghera fe lt/Cookstown area has a lready be en de fined and programm ed .
-64- Th e technique used for the comparison of option s has , in the first
instance , been the de rivat ion of a long-term unit cost of water, expresse d 3 in pence/m . Th is take s into account cap ital and operating costs of the new scheme and any sav ings to be ma de in no t operating more expensive ex isting sources , when overa ll surp lus capacity pe rmits .
It shou ld be noted th at the appraisal of p ro jects is on the bas is o f
engineering econom ics only . Other factors , such as env ironm ental , social ,
legal , and wate r qua l ity aspects , and land costs are not within the scope of this report .
It ha s bee n taken ,that costs will rema in constan t in real terms at
mi d 198 3 leve ls , except for electr icity whi.Ch is assum ed to increa se by 1.9
pe r cent pe r yea r in rea l term s . The un it cost of water is sensitive to the fo llow ing factors :
(i ) rate of increa se in demand ; (ii ) discount rate used ;
(iii ) time of introduction of the new sou rce (reflecting rea l
in creases in the cost of elec tric ity ).
Uncertainty over the effe ct iveness of leakage reduction programmes p revents accu rate estimation of the timing of in troduction of new sources
un til such pro grammes have bee n estab lishe d and operat ing for some time .
Consequently for the purpose of identifying the next so urce to be
deve loped , it has been assumed that the next sou rce wi ll be required when
the ca ll on sources ma de up of ident ified dema nd p lus an operating marg in p lus an economica lly atta inable quantity of leakage eq uals the rel iab le yie ld of ex isting sources . Thereafter the ca ll on sou rces is assumed to inc rease by a fixed pe rcenta ge pe r year from a ba se of the current reliab le y ie ld .
The effe ct of the rate of increase of prod uction requirements after in tro duct ion of the new source has been studied by usin g rates o f 0 .5, 1.0 and 1.5 per cent pe r yea r . Within th is range the cho ic e of new source can vary ; for higher grow th rates, checks have been ma de to show that whilst large r capacit ies may be indicated , the source for the first-in scheme rem ains the sam e . The b and of grow th is consistent w ith the forecasts discussed earlie r in this repo rt .
-65- Wh ere the new sou rce is sma ll in re lat ion to the demand wh ich it is supp lying, analysis has concentrated on 1.0 per cent annual grow th . Fo r large r schem es the un it cost is ca lcu lated for the three rates of growth . Pa rt icular no te is taken of those schem es who se sensitivity to growth rates is small.
7 .2 EASTERN DIV ISION
7 .2.1 A lternat ive Schemes
Four ma jor schemes have bee n oonsidered for the next ma jor source for Belfas t : their locations are shown in Fig . 7 .1. The first two schemes outlined be low have been de rived by re-examination of earlier propo sa ls by o thers and the latter two have been deve lop ed in the course of this stu dy .
Th e compariso n of schemes was init ia lly confined to the costs assoc iated w ith producing and delivering water to the ex isting rese rvoirs and trunk ma ins around Belfast , takin g into account a propo sed Cross Town Main p rev ious ly id entified by the W ater Se rv ice as necessary for no rth - south tra nsfe rs . Becau se this app roach tended to favour undu ly those sc hemes situated to the north of Belfa st , more deta iled consideration has been given to the sizing of all the new major trunk ma ins in order to p rovide water at the locations where it is most likely to be required in the futu re . These considerations have been allowed for in the follow ing rev iew of schemes .
Glenwh irry (GW )
Th is proposed up land rese rvo ir to the north of Belfast would enta il a dam o f up to 30 m height , wou ld flood an area of up to 400 ha and , by developm ent of a numbe r of catchw aters , yie ld up to 180 M l/d . Fu ll treatment works wou ld be provided in the v icin ity of the dam from wh ich a
30 km pipe line wou ld de liver supp lies to a new reservo ir at Mossley at an elevat ion of 122 m , just no rth of Belfa st . From Moss ley a pipeline wo u ld lead down to O ld Park initially and the rea fter on to Breda Rese rvo ir . Ferguson and McIlve en 's report on th is sou rce p roposed that reservo irs of 40 ,000 M l and 44 ,000 M l with capac ities of 140 Ml/d and 175 Mild resp ec tively cou ld be built .
-66- Dungonnel l
Priesthill
BALLYMENA Crebill y LARNE
„Glenwhirry
Creavery E N,
•
ANTRIM Mossley - - Dunore \ , .... - - • Pa • nt • I Hyde Park BANGOR
LOUGH NEAGH Old 0 N E W T O W N A R D S
BELFAST Tunny Point `0 Breda Purdysburn Castor LISBURN Bay • • • S. •
S. j r?...IRGAN • S.
LEGEND c( 0 - Exist ing Source Mourne \ Conduit <., r - New or Extended Source Drurnaroad C I Service Reservoir Exist ing Pipeline New Pipeline
0 5 10 Lough Scale I— Kms Island Reavy
Kinnahalla
() NEWRY Silent 1.4311ey EASTERN DMSION Development Options F i g ur e 7 . 1 In this report , by utilisat ion of slight ly sma ller rese rvoirs and by po stponement of any decision to utilise the mo re expensive catchwaters ,
s lightly sma ller yie lds hav e been considered , namely 110 Ml/d and 140 M l/d .
The capital co st o f these two developm ents have been ca lcu lated as follow s :-
Fo r 110 M l/d : 28 ,723 ,000
For 140 Ml/d : 34 ,822 ,000
Fo r the larger size of reservoir some eight prope rties wou ld be inu ndated along w ith 400 ha of land wh ich is predomi nantly up land bog and rou gh grassland much of wh ich is already liable to frequent flooding . Fu rther deta iled consideration of this site is likely to confirm the view
tha t an even sm aller reservoir of a round 17,000 M l, flooding 260 ha and only th ree prope rt ies could y ield a round 8 5 M l/d w ithout significant
inc rea se in the un it cost of wate r ; however a good gravity supp ly wou ld
have been underdeve loped .
Fe rgu son and Mc llven 's pre lim ina ry repo rt identified compensa tion water
req uirements o f 2 1.5 Ml/d . If there were a req uirem ent for th is to be ,
say , doubled , it cou ld be achieved by inc reasin g the height of the dam , for the sma ller schem es , by about 2 to 3m at a co st of up to £ 1.5 million , which wou ld effec tively increa se the un it cost of wa te r by about 4% .
Tunny Point
Th is new prop osed sou rce has bee n sited to abstract Lough Neagh water
at a po int where the water is likely to give least treatment prob lems and to delive r it after treatm ent to Pu rdysburn Re se rvo ir (elevation 96 .0 m ) to the south of Be lfa st . A land take of 40 ha of good agricultural land beside Lough Neagh wou ld be requ ired . Acco rdin gly , previous stu dies have a lso looked at siting the .treatment works on land a lready ow ned by the Wate r Service at Stonyford but with the same ab strac tion and ultimate delivery point . Th is seco nd scheme was show n to be less expensive than the
first , but the di ffe rence was predom inant ly attributab le to the lower co st of serv ice rese rvo ir storage , an item wh ich has not been considered in the current econom ic compa risons because it is common to all schem es . Acco rdingly the origina l scheme for tre atment by the lough is the one considered in th is study .
-67- Dunore Point
Au gmentat ion of the ex isting abstract ion , treatm ent and distr ibut ion
fac ilities at th is Lough Neagh s ite would ma ke use o f m any facilities
a lready availab le at this site and hence reduce cap ita l and ope rat ing
.co sts . Dup lication of the p ipe line with cross connect ions to the eX ist ing p ipeline wou ld give a sign ificant security bene fit and pe rmit repairs wh ilst mainta ining a h igh p rop ortion of the ou tput . The drawback of th is
scheme is that it de live rs by pumping to the com paratively high elevation of 135.6 m at Hyde Park Rese rvo ir . In add ition there a re now only restricted routes for ma jor trunk ma ins into the city from Hy de Pa rk . Th is latter po int would have to be co nsidered in great deta il befo re recommending imp lem en tation of this scheme .
Castor Bay
Castor Bay is current ly the th ird la rgest wate r supply in No rthe rn
Ireland and predom inan tly sup plies the Southern Division . A scheme has
bee n p ropo sed which take s advantage of existing faci lities . This scheme
invo lves extension to the existing treatment works and delivers to the
south of the city , wh ere fu rther wa ter is most likely to be required , at the compa rat ively low e levation of Breda Reservo ir (elev . 67.0 m ), but w ith
a connection to Old Pa rk Rese rvoir (elev . 58,2 m ) in the cen tre of the city , as the initial point of delivery . The water req u irements at this elevation wh ich are not already p rov ided by Woodburn are app roxima tely 110 Ml/d . If greate r quant ities a re p rovided from th is new source , they wou ld hav e to be repumped to highe r elevation .
The capacity of the existin g treatment w orks at Castor Bay is known
to be adverse ly affected by al gal b loom , far mo re so than at Dunore Point .
No ma jor scheme can be recommended for this site until a solution to th is problem is fou nd . Eithe r the p lant must be down rated , the method of treatm ent va ried or the intake mov ed to a better site , and the relevant costs taken into account .
A furthe r option , based on an alternative intake , wou ld invo lve loc ating a new treatment works c loser to the intake . Such a scheme would req uire a longer delivery pipe line , the advanta ges of flexibility between Southe rn and Easte rn Div isions would be lost and admi nistration costs wou ld increase .
-68- 7 .2 .2 Ca ital Co sts o f Sch eme s
Fo r th e grav ity schem es th e y ie ld usu a lly de fines the capac ity of a ll comp onents o f the scheme inc lud ing the s ize o f pip elin e . By co ntra st in a pump ed su pp ly , th e cho ice of pipe l ine d iamete r w ill depend a lso on the ca p it a l and opera ting co sts .
Fo r the th ree pum ped schem es an aly s is of th e econom ica l cap ac ity of the p ip el in es has be en ca rried o ut fo r each scheme using the e xp ected e lect r ic ity prices . Th is ind icated tha t the economic ve loc ity o f water at fu ll capac ity is much low er th an in most o f the existing ma jor schem es .
Th is is of particu la r sign ific ance for Du nore wh ere a second p ip e line wou ld a llow sha ring of the co mb ined ou tp ut .
The co sts of th e fou r ma jo r schem es at diffe rin g capa c ities is giv en in Tab le 7 . 1, and mo re deta ils a re tabu lated in Appe nd ix 9 .
T ABLE 7 .1
CO ST S AND Y IE LDS OF POSSIBLE NEW MAJ OR SOURC ES
Annua l Op e rating
Sc heme Y ie ld Cap ita l Co st Co st at fu ll
(M l/ d ) x 10 3 Cap ac ity
-69 - 7 .2.3 Ope rating Costs
For schemes requ iring a new treatment wo rks , a fixed annual cha rge has been allowed to cover attendance and ma na gement . Other costs vary in proportion to p roduction . Fo r the up land sou rces these costs are ma inly pu rchase of chem ica ls for trea tment plants . Fo r i.he Lough Neagh sou rces , where slow sand fi lte rs are used elec tricity for pump ing is by far the mo st sign ificant va riab le co st .
Because of the high pumping head and high power costs of the ex ist ing Duno re Scheme , any other p roposed scheme shou ld be operated at fu ll capacity from the start of its life , with the output of Duno re cut back to - the m inimum necessary to m eet demand . This w i ll resu lt in the maximum reduct ion in ope rating costs .
Considerat ion has been given to the possibility of introducing a new sou rce so lely to redu ce electr icity co sts at Duno re . In a typ ica l case of
introducing a G lenwhirry scheme one year earlier than needed , the effect is as fo llow s :-
It is conc luded tha t currently it is uneconom ic to introduce a new scheme so lely to reduce operating costs of the most expensive existing scheme . However , if electricity pr ices continue to rise at 1.9 percent annually, in real terms , in 35 years time th is w ill no longer be the ca se .
Consideration has also been given to the effec ts of the phased int ro- duction of treatm ent works and pumping p lant and ft can be shown that there is no advanta ge in such phasing for any new scheme since the costs are mo re than ofEset by sav ings at Duno re . This conclusion introduces the poss ibility of provid ing enough water to perm it the Mourne Conduit to be closed for repa irs a nd provides an alte rnat ive to the complete rep lacement o f that conduit .
-70- 7 .2.4 Mou rne Condu it
The Mourne Condu it is now over 90 yea rs old and th e poss ibility of its refurbishment must be considered in con junct ion w ith the introduct ion
o f a new sou rce . Alrea dy the rep lacem ent of the first third of the condu it has been underta ken on the grou nds that structu ral strength , redu ction in
capac ity and lea ka ge had approached una ccep table levels and the conditions
in the rema in ing two th irds are likely to be sim ilar . Such work has assumed that the condu it 's two tunne l sections at Dona rd and Carryduff , w h ich wou ld be d ifficu lt to rep lace , a re in sa tisfacto ry cond ition and ne ed
no si gn ificant wo rk .
Th e need to refurb ish the tr iplicated pipe line section s of the co ndu it p rov ides litt le cho ice of method since there wou ld appear to be no v iable long term alte rnative to rep lac ing the oldest p ipeline . This can be done by laying a new p ipeline (1000 mm diamete r ) .alongside the old , rapidly
cross-connect ing them and then abandon ing the oldest pipeline .
For the open channel sections of the condu it , there is the poss ib ility of work ing inside the conduit to effect its repair or relining ,
the latter be ing a longer te rm so lution . Re lining, incorporating an increase in the structu ra l strength of the condu it , wou ld be like ly to
reduce its cap ac ity by up to one third (some 40- 50 M/ ld ). Th is loss wou ld have to be recovered by a new pipeline (m inimum diameter 900 mm ): howev er comp lete rep lacement (1400 mm ) wou ld appear cheaper than relining p lus the smaller pipeline , (£ 3 13/m against £ 200 + £ 170/m ).
The temp orary works req uired to mainta in supp lies along the route of the condu it , wh ilst work ing ins ide the conduit , would add sign ificant costs to tho se of the perm anent works in some case s .
Three po ss ible so lut ions are availab le for the section of conduit from between Donard and Ca rrydu ff tunnels and prelim inary est imates are :
A Permanent Rep lacemen t . (£ 8 ,524 ,000 )
B Temporary Byp ass and Repa ir (£ 5,68 1,000 ) w ith later
Rep lacement (£ 8,524 ,000 )
Tem pora ry Alternative Supplies and Repa ir (£ 7 ,326 ,000 ), w ith later Rep lacement (£ 8,524 ,000 )
-71- So lutions B and C wou ld invo lve pu rchase of pip e for the pipe line sections , but laid in itia lly in pa rallel with the op en cha nnel sections wh ilst repair wo rk was carried ou t inside : upon comp le tion the pipeline would be rela id in pa ra llel w ith the p ipe line section . Solution B requires the installatio n of in-line boo ster pump s to mainta in the fu ll output from Silent Valley . So lution C req uires relat ively sma ll q uant it ies fo r supp lies on the route of the conduit , and alte rnative supp lies from a large new sou rce with pum ps and p ip eline to provide water from Breda Reservoir to Purdysburn Reservoir and asso ciat ed ope rating costs .
It can be seen that So lution A is the most econom ical unless the repa ir wo rk , wh ich wo uld be confined to the inside of the conduit , can po s tpone the necess ity for ca rrying out the st ructura l strengthening for at lea st 20 years .
In view of the limited know ledge of the rema ining usefu l life of the condu it , it is considered pru de nt to accept that the p ermane nt rep lacem ent
(So lution A ) is the pre ferred me thod of securing supp lies from the Silent Va lley . Th is dec ision ma kes po ssible the furthe r deve lopment of the Lough
Island Reavy source at the earliest time because it is possib le to build in capac ity for the extra supp lies . The dec ision also means that any m ajor new sou rce does not have to be large enou gh to supply the equ ivalent yi eld o f Silent Va lley whilst the condu it is closed down .
7 .2.5 Lou h Island Reav
At a sma ller sca le than the fo rego ing ma jo r schem es , Lough Island
Reavy offers an att ractive po ss ibility . The cu rrent y ie ld of the exist ing re se rvoir , quoted as 18 M l/d , could be increased by th ree alternative de ve lopm ents :-
L (A ): development of a dam and a reservoir on the Spe lga River and of further catchwaters to supp ly bo th the new and ex isting Lough Island Reavy Rese rvoi rs , to give an extra yield of 65 Ml/d ;
L (B ): development of all the same catchwate rs as in L (A ) but withou t
the new rese rvo ir, to give an extra yield of 40 M l/d :
-72- L (C ): deve lopment of further catchwaters adjacent to L ou gh Is land Reavy , to give an ex tra y ie ld of 17 ml/d .
A ll th ree dev e lopm en ts have been co sted on the basis that full
treatment works wou ld be p rovided for the ind icated capacity , but no
a llowance has been made for the costs o f provid ing sim ilar treatment fac ilities for the existing 18 Ml/d of y ie ld . The location of such
treatment works can either be be side Lough Island Reavy or at Druma road at the north end of th e New ca stle Syphons , as discu ssed in more de tail in the
report , Siting of Wate r Treatment Works , January 198 0 , by Messrs . Ferguson Mc Ilveen . In either ca se , the capital costs for delivery of treated water at Drum aroad are considered to be the sam e and for the three schemes are as fo llow s :
Fo r furthe r deta ils of cap ita l and ope ration costs , see Appendix 9 .
For delivery of th is inc reased y ie ld to Belfast , it can be shown that
a separate pipe line is uneconomi ca l and that advantage shou ld be taken of
the need to ca rry o ut refu rbishment of the Mourne Co nduit, as considered in more deta il in Sec tion 7.2 .4 , by comb in ing the two pro jects . It ha s been assum ed that for the smallest scheme the yie ld can be accomm odated in a
sli ghtly large r diameter replacemen t of the Mou rne Co nduit in the 20 km sec tion from Druma road to the Carrydu ff Tunne l at the time when it is req u ired to be rep laced . For the two la rger cap acities it has been assumed that the Carrydu ff Tunnel wou ld have insu fficient capacity to transfer all water to the term ina l rese rvo ir at Pu rdysbu rn and an add itional pipe line wou ld be needed . On the basis that the replacement of the Mo urne Conduit between Drumaroad and Carryduff Tu nne l to ma inta in ex isting yie lds is necessary and wou ld cost £ 6 ,196 ,000, the capital cost of tra nsfer of the
increased yie ld to Purdysburn is estima ted to be as fo llows :
-73- Total Cost Co st of
of transm ission Rep lacement Effect ive Cost
system Section
The costs of this scheme are given in Tab le 7 .2.
TAB LE 7 .2
COST S AN D YIELDS OF LOUG H ISLAND REAVY .EXPAN SION
Sequentia l development can be ca rried out from L (C ) to L (B ) to L (A ), but th is wou ld result in slight inc reases in costs .
The economical development of this source is entirely dependent upon action being taken to ca rry out perma nent refurb ishment of the Mou rne
Conduit . If th is po licy is not adopted the dev elopmen t of the Lou gh Island
Rea vy so u rce is no longer at tractive .
7 .2.6 Com arison of Scheme s
A comparison ha s been made of all of the foregoin g schemes sized on the basis of the y ields of the availab le grav ity sou rces .
To find an initia l ranking o f schem es of each cap acity , the average cost of water produ ced at the full capacity of each w as calcu lated and ranked accord ingly in Table 7 .3.
-74- TABLE 7 .3
RANKING OF EASTERN AREA SCHEMES (assum ing rea l increase in cost of electricity )
(p/m 3 of new water produced at fu ll cap acity )
Capac ity Ml /d :- 17 40 65 110 140
Rank 1 L (C ) 5 .1 L (B ) 6 .9 L (A ) 6 .5 GW 5.8 GW 5 .5
2 CB 7 .9 CB 6 .8 CB 5.9 CB 5 .9 3 DP 8 .6 DP 7.4 DP 6.8 TP 7.0
4 TP 8 .4 TP 7 .4
where L (A ), L (B ). and L (C ) = Lough Island Reavy
GW = Glenwh irry CB = Ca stor Bay DP = Duno re Po int TP = Tu nny Po int
In view of the above rankings , further consideration of the Tunn y
Po int and Dunore Po int schem es was considered to be unnecessary .
As the above figu res are for continuous operation at the rated capacities of the schemes , they do not take accou nt of the und er- utilization ,that will oc cur du ring the ea rl ier years fo llowing commi ssion ing. Sequences of dev elopment op tions were th erefore developed to cate r for 20 years of growt h at 0 .5, 1.0 and 1.5 percent pe r year increase in production and the resu lting unit costs of new supp lies of water were calcu lated and are as shown in Append ix 10. Table A .10.1 and A .10.2 give the unit costs for the first scheme commencing operat ion in 1992 and 2002 respe ctiv ely .
-75- Of the ma jor schem es , the most economi cal would be the developme nt of
Glenwh irry at a capac ity around 110 Ml/d , wh idh be com es more attract ive w ith increase of elect rical costs . Howev er , th e advantage of this schem e over one of simi lar capa city at Ca stor Bay is very sma ll particu larly at the highe r rates of growth . As a consequence secondary facto rs have to be considered . These include : a . land acqu isition b . compensation water requ irements at G lenwh irry c. the p roblems due to algal bloom wh ich affe ct the output of treatment
works using Lo ugh Neagh as a source .
In th is last case the difficu lties of treating Castor Bay w ater have to be fu lly investigated . Possible solut ions could inc lude mo ving the intake and treatment works to a more favourable location, whilst reta ining the same concep t of a pipeline to the low level reservo irs in Belfast . Aga inst this so lution a re the follow ing factors :-
(i) the de livery pipeline wou ld be lon ger ;
(ii ) further coldmon facilities wou ld have to be prov ided ; (iii ) superv ision and manageme nt costs wou ld have to be duplicated ;
(iv ) the be ne fits of a single source to cater for the growth in dem and of both Eastern and Southern Divisions wou ld be lost ; (v ) there mi ght be oth er water qu ality p roblems on the east side of Lough
Neagh if qu ar ryin g were to dev elop in tha t area .
It is therefo re necessary that the so lution of treatment p roblems must be overcome on the Castor Bay site and it should be noted that simi lar prob lems have been reduced at Dunore Point . Action is be ing tak en to reduce the output of nutrients into Lough Neagh from sewage treatment p lants , to lim it algal growths and th is is expec ted to be effective . If treatment p rob lems can be proved to be mana geab le at rea sonab le co st , then the effect o f the two other ma jor factors o f land acqu isition and compensation w a ter (which tend to raise the cost o f the impoun d ing schem e ) will be such as to make the Castor Bay schem e more attractive than the
G lenwhirry schem e .
-76- At a sma ller scale , provided that fu nds are alloc atsd for the renov ation of the Mou rne Co nduit , the add itional capital oosts needed to
prov ide for a furth er 17 M l/ d from Lough Island Reavy (L (C )) are
proportiona lly sma ll. Th is is th erefore an attractive scheme . The larger Lou gh Island Reavy schem es (L (A ) and L (B )) wou ld requ ire new route s for
p ipe lines to Belfast and wou ld therefore be mu ch less econom ical . How ev er fu rthe r tests are currently be i n g conducted on the cap acity of the Mourne
Co ndu it which may rev eal that t he extra y ie ld from some of the add itional catchwaters considered for the interm ediate deve lopment (L (B )) can be
ca rr ied in the r e p l a c e me n t p i p e l i ne along t he ex isting route of the condu it .
7 .2 .6 Sensitivity to t h e C o at of Electricit
As a test of the sensitivity of t h e unit co st of water to the cost of electricity , the whole of the abo ve exercise has been repeated using constant electricity p rices . The ranking of individu al schem es is given
Table 7 .4 and the rankings of various sequences of schemes are given in
Append ix 10, Tab le A .10.3.
TABLE 7 .4
RANK ING OF EASTERN AREA SC HEMES
(constant electricity costs ) (p/m 3 of new water produced at fu ll cap acity )
Scheme Capacity (M l/d )
Rank 40 65 110 140
L (C ) 4.9 L (B ) 6 .7 CB 6 .2 CB 5.6 CB 5.3 2 DP 7 .6 L (A ) 6.5 GW 5 .7 GW 5.5
3 DP 6 .9 DP 6 .4 TP 6 .3 4 TP 7.8 TP 6.6
- 7 7- Th ese tab les ind icate that with constant electricity costs Castor Bay is slightly more economical than G lenwhirry , a lthough the sma ll development at Lough Is land Re avy rema ins the most attractive econom ically .
7.2.7 Bangor Reservo irs
The six Bangor rese rvoirs in the north of the Downpatrick sub- div ision lie between Bangor and Newtonards in c lose proxim ity and involve five sep arate water treatme nt plant s , some of which are in need of renewal .
These sources have in recent years p rov ided outp uts of 10-11 M l/d , w ell in excess of the ir reliab le yie lds , because these sources have alterna tive supp lies available from the Mourne Condu it in times of emergen cy .
Rat ionalisation of these sou rces has to be con sidered along one of the fo llowing lines :-
Ab andonment of these sou rces and reliance on the Mourne Condu it for
all supp lies . b . Co llection of the raw water from all the rese rvoirs at one or two
sites for treatment in ren ovated works .
Renov ation of the existing wo rks in their p resent mode .
So lution a , which could in p ract ice only be imp lem ented after the provis ion of a ma jor new source for Belfa st , wou ld place an ad ditiona l call on the new source and bring forward the date of y et ano ther new source .
Th e analysis for the Eastern Area as a who le has suggested tha t most of the ext ra w ater which can economica lly be deve lope d at Lough Islan d Reavy can be transmi tted into Belfast prov ided that the rep lacement of the Mourne Condu it up to the Ca rryduff Tu nnel is provided w ith adequate capa city . Th ere is therefo re little water that can specifically be reserved for
Downp atrick sub-division ; such qu antities as are availab le can be tter be utilised further sou th in suppo rt of even sma ller sour ces at such places as
Ki llough , Tannaghm ore and Lough Money . Th ere fore it is advisab le to prese rve all ex is ting sources if at al l po ssible , wh ilst minimi sing further cap ital and op erational expenditu re .
-78- Solution b would call for the delivery by gravity of .the raw water
ou tput of Ho lywood Reservoir to Creightons G reen Reservo ir and the comb ined
output to Ba llysa llagh Upper Reservoir ; the output of Con lig Upper and Lower Reservoirs would be pumped to Ba llysa llagh Lower Reservoir . The two
adjacen t treatment wo rks at Bally sa llagh cou ld then be renovated and expanded to cope w ith the yie lds . Increased distribu tion ma ins wou ld then
be requ ired to distribute the water .
Solut ion c imp lies an acceptance of the existing situation with
persistence of ex tensive fixed ope rating costs and the ex tra cap ital co sts
of at lea st four of the treatm ent wo rks .
In co nsidering the re lative merits of these three solutions it would
appear uneconomical to d iscard such a sign ificant source of 10 M l/d capacity in an area wh ich is likely to continue to expe rience above average
rates of grow th . Hence So lution a is con side red to be unrealist ic . For a compariso n betw een So lut ions b and c the co st o f divers ion p ipe line s ,
(app rox £ 500,000 ), is less than the ex tra costs of renovation of treatment works at severa l site s and the higher operat ion charges . Howev er the costs of develop ing alternative supp lies of treated water to re servoirs d ire ctlS, supplied from the diverted sou rces requ ires further investigation and is considered to be beyond the scope of the p resent stu dy . However it appea rs that such a investigation would be wo rthwhile .
7 .3 BA LLYM ENA/ANTR IM/LA RNE
Althou gh inte rconn ected with Ea stern Div ision by virtue of its conmlon source at Duno re Po int , this are a , sh own in Fi gu re 7 .1, can in pa rt be co ns idered sepa rate ly . Ow ing to their low stora ge ratios , difficu lty has been experienced in op erat ing the Dungonnell , Qu olie and Ki lly lane reservo irs close to their theo retical yields . Consideration has been given to increasing the sto rage at Dungo nnell and alternatively the extension of the pipeline bringing Lough Neagh water from outside Antrim to outside Ba llym ena .
-79 - Ferguson Mc llvee n (Ju ne 1982 ) reported on the Dun gonne ll - Inver Augmentation , and comp ared the costs of ra ising the ex isting dam w ith the
co sts of constructing a second dam on the ad jacent Inve r Rive r which already feeds the ex istin g reservo ir through ca tchw aters . From the repo rt
it can be inferred that for optimum ut il isation of resources the second
dam is a more econom ical so lution . The original scheme w as bu ilt w ith th is po ss ibility in mi nd and the outlet pipeline from the treatm ent works was sized accordin gly at a stated 2 1.5 Ml/d . In addition there is a pump ed outlet of 2 .5 M l/d delivering to the north-east coastal strip .
Anticipated yields and unit costs of water are shown in Tab le 7 .5, for
variou s sizes of new reservoir . Be ing a small source serv ing a large area , different rates of grow th make ne glig ible difference to the unit cost of water .
The un it cos t of water for increasing sizes of rese rvoir is shown to be decreasing . However the cost of extra distribu tion p ipew ork in
excess of that already installed , would render the larger schemes less economical . Subject to hydrau lic check of the m ain outlet p ipe line , it wou ld appe ar that the optimum schem e is one fully ut ilising all existing ou tlet p ipe lines i .e . with an in creased yie ld of som e 11.4 M l/d from a re se rv oir of 166 0 Ml net cap acity , costing an est ima ted E 3 .2 mi llio n .
TAB LE 7 .5
COST OF WATE R FROM INVE R DAM
Re servo irs Net Reliab le Unit Cost of New Dungonne ll Inv er Yield 1 Water (p/m 3) (MI ) (M l ) (Ml /d ) at Works
1 Net of 3% washw ater .
-8 0- Consideration has also to be giv en to the utilisat ion of this enhanced p roduct ion . Cu rrently the interco nnection of Ba llymena to Antrim
and he nce to the Easte rn Div ision is limi ted . In the pa st con sideration
has been given to ex tend ing the Dunore supp lies to the north to p rov ide additiona l water to Ba llym ena , by building a pipeline from clo se to
C reavery Rese rvo ir to Creb illy Re s e r v o i r outside Ballymena . This solu tion was considered to be cheape r than extending the Dungonnell rese rvoir and
its treatment w orks , but it fails to p rovide extra resources . How ever if
the pip eline is seen in a dual capacity of first ly prov idi ng supp lies northwards and therea fter supp lying the excess resources of Dungonne ll/Inver southwards , its con structio n can be justified and add
little to the unit costs of water . A 400 mm diam eter p ipeline to ca rry up to 10 M l/d is considered to be approp riate and wil l cost £6 00,000 init ially and a furth er £ 300,000 for extension when the dam is comp leted .
Th is schem e has a lower un it cost than any of the equivalent schemes in the Be lfast Area . Its construction wou ld perm it a tempo rary a llocat ion
of more of the Dunore resource to Belfast . It is therefo re considered to be the mo st favou rab le new source in the Eastern Area , and shou ld be first
in any development pro gramme , even thou gh of sma ll size . It has been noted that work is be ing ca rried out to perm it water available at Lough Mo u rne in Eastern Div ision to be pumpe d to La rne in the east of this area .
Th is dev e lopment of Inver dam and its p ipeline shou ld be ab le to
ass ist Be lfa st to the exte nt of around 2 yea rs increase in demand based on p ast expe rience , but account would have to be taken of the time needed for
its prom otion and construction .
7.4 COL ERA INE/ BALL YMONE Y/MOYLE
In th is area , shown on Figu re 7 .2, the Al tnah inch reservoir suffers from a low sto rage ratio and consequent ly difficulty is expe rienced in op erating th is source close to its theoretica l reliab le yield . However for some m onths of mo st yea rs add itional water is av ailable , but wou ld require
the construction of furth er treatm ent works and a new pipe line down to Ballym oney and onwards to Co le raine in order to utilise the water .
-8 1- M I M I IS a • I S S O a M I • a • INN 1• 0 • M I • M S 11111 I le I S
LEGEND < I— Existing Source C I — New or Extended Source 0 Service Reservoir Existing Pipeline New Pipeline
0 1 2 3 4 5 Scale Km Carthall COLERAINE
Ballinrees
0 N % .4. N 'N...... 4" - • .. .. _ .. . Castleroe N. S. Pumping Main S. fronn R.Bann .(Ss
BALLYMONEY
Glenlough
Altnahinch
COLERAINE/ BALLYMONEY / MOYLE Development Options Th is propo sa l wou ld not imp rove the reliab le yie ld of the sou rce , but would reduce the pump ing current ly required to supp ly Co le raine . It is unde rstood that a propo sa l has been made to build a second dam upst ream of the A ltnah inch dam , but un fo rtun ate ly deta ils of such a dam are not ava ilab le . It has been assumed th at it is worthy o f future fur ther consideration as a source .
At Co leraine som e relatively m inor expenditu re on raw wa te r pump in g plant and later on treatment works would p rovide a ll the compon ents of that scheme with simi lar capacity .
Investigations to find the optimum deve lopm ent pa ttern rev ea ls the fo llow ing :
(i ) construction of an interconnecting pipeline betw een Altnahinch and Ballinrees sources cannot be just ified on the grounds o f savings in ope rationa l costs alone ;
(ii) when the A ltnahinch supply ne eds augmentat ion , the most econom ical so lut ion so far iden tified is to connect it to the Ba llinrees sy stem by a pipeline from Ba llinrees treatment
works via Carthall Rese rvoir in Co leraine to G lenlough Reservoir ou tside Ba llymoney .
(iii ) Augme ntation of the Ba llinrees wo rks to the extent of matchin g the pum ping and treatment capac ity to th at of the pipeline is
more econom ical than extending the Altnah inch supp ly .
(iv ) Wh en further resou rces are need ed , it is likely that up land sources will be more economical than river abstraction . Th e
constru ction of a second dam at Altnah inch wou ld p rovide the most econom ical sou rce of this type so fa r ident ified . Prior construct ion of its treatment worke and outlet p ipe line wou ld be econom ical but not essen tial . The extent o f spare capacity in the Altnah inch treatment works and outlet pipe line
is not known precisely an d wou ld have to be checked befo re
sizing the augmentation o f these two items .
-82- From the Re giona l Stora ge/Y ield re lationship , the reliab le yield of
Altnah inch after allowance for compensa tion wa ter (3.2 1 Ml/d ) and w ashwater (0 .3 Ml/d ) is 11.0 M l/d . Add itiona l storage of 1360 ml , would increase th is y ie ld to 17.6 Ml/d . Prior to construction , optimum sizing would have to be undertaken . In order to allow for optimum utilization of wet weather flow , the treatment works and outlet p ipeline should be designed for capacities of 23 M l/d and 22.4 M l/d respectively , at which rate it sho uld be ab le to ope rate fo r 4 years out of 5 .
Th e programme of deVelopm ent is therefore lik ely to be :
(i) extend raw water pumphou se and plant for Ballinrees to p rov ide adequ ate standby fac ilitie s . (£300 ,000 ).
(ii ) when Altnahinch is fu lly commi tted , connect Ba llinrees to G lenlough Serv ice Rese rvoir (£ 1,150 ,000 ).
(ii i) when Ba llin rees is fu lly commi tted , extend raw wate r pumping
p lant and treatm ent works by 7 M l/d to match the cap acity of the raw water pum ping ma in (E 700 ,000 ).
(iv ) when Ballinrees raw water pumping main is fully committed , build the second Al tnah inch dam (of the order of £4 to £6 mi llion ).
7.5 SOUT HERN DIV ISION
In the Southern Div ision , Figure 7.3, plans for taking further supp lies of water from Cam lou gh to supp ly Newzy are well advanced . It is unde rstood that implem en tation has been delayed by conflict of interests with the cu rrent owners of the water ri ghts . Con sideration has to be given to the alterna tive sources of supply if this problem canno t be reso lved .
The immmed iately apparent alternative is to ma ke pe rma nent use of
Lough Is land Reavy , wh ich wou ld entail either :
(a) a trea tment works besi de Lo ugh Island Reavy w ith pumps to de liver wate r into the ex isting East Main out of Fofannybane
T reatm ent W orks -83- ON M O N M a S I MM I = a IS N O N M OM 0 M O • M O a M I a=
To BANBRIDGE LEGEND c( : )— Existing Source < Tr - New or Extended Source East Treat ment Work s Main Service Reservoir Existing Pipeline
New Pipeline West Main 0 I 2 Scal e 3 4 5 Km To MOURNE W NDUIT Lough Island V- - Reavy
Foffannybane
Foffa nny
Newry Trunk Main Spelga NEWRY PiCamlough
Development Options SOUTHERN DIVISION or (b ) pumpin g raw water to Fofannybane and constructing an extension
to the treatment works at that location .
The former alte rnat ive elim inates the need for a new pump ing ma in an d
allow s the treatment works to be used for Eastern Division . This
a lternative is there fore considered further .
The cap acity of the distribut ion ma ins out o f Fo fannybane Treatment Wo rks is adequ ate to cater for the increases in pumping out of Lough Island
Reavy . By contrast , if the Cam lou gh sou rce is dev elop ed and imm ed iate
utilisation of all its capacity is requ ired to make use of this gravity
source , then a ma jor increase in the distribution ma ins out of Fo fann ybane
w ill be requ ired . Typically the ex isting 250 mm West Distribution ma in
wou ld be rep laced (due to age as we ll as low capacity ) by a ma in up to 400 mm diameter to give adequ ate connection to the Ca stor Bay supp ly .
Three po ssibilities have been rev iew ed , and the cost of water derived
for each .
(i ) Cam lou gh w ith interconnect ion to Ca stor Bay 11.46
(ii ) Camlough without inte rconnection to Castor Bay 10.86 (iii ) Lough Is land Reavy 14 .35
From these figu res it can be concluded that utilisation of Lou gh Island Rea vy is one th ird mo re expensive th an usin g Cam lou gh . Furthermore there is no econom ic advanta ge in providing furthe r ma jor interconnection with the Ca stor Bay system (in a northerly direction ), until such time as any exce ss capacity at Camlough can be made available to Castor Bay supp ly area to po stpone cap ital dev elopment at that site . Precise sizing of that fu rther inte rconnection will depe nd on the relative rates of growth of the two areas .
-8 4- Priority for Develo ment in Southern Division
Th e Spe lga/Fo fanny source is cu rrent ly over extended and is be ing
a ssisted by sma ll contributions from Lough Is land Reavy and increasingly by Ca stor Bay . Increa sing dema nd w ill req uire a new p ipeline from Ba llydu ggan
Rese rvoir down to Banva le Junct ion at an estimated cost of £ 300 ,000 . Th is method of supp ly can continue for some years p rov ided that there is surplus
cap ac ity at Casto r Bay at all times of the yea r . Th is assum es that a perma nent so lut ion to the dif ficu lties crea ted by algal bloom can be found ,
eith er by permanen t down rating of the plant or by the add ition of a fu rther sta ge of treatme nt for use at d ifficu lt times .
Thereafter the Cam lou gh schem e should be brought in at an est ima ted
co st of £ 3.1 mi llion . At the same time a fu rther p ipeline from Fo fannybane w ill be required to rep lace and increase the capac ity of the West Trunk
Main at a cost of £ 1.15 m illion .
7 .6 STRABANE/OMA GH
Recent developm ent of further catchwate rs to rep lenish the reservoirs
at Lo ughs Fingrean/M acrory and Brad an has reduced their storage/y ie ld rat ios . Consequently at these reservo irs and at G lenco rdia l , there is plenty o f w ater availab le during severa l months of many yea rs . At Lough Bradan inte rconnection with the pumped sou rce at Kil lyhev lin already ex ists and connection w ith the River De rg supply area is con tinuing to be
deve loped . Th ese connections pe rm it som e operationa l sav ings . For Lo ugh Fingrean/Ma crory and G lenco rdial consideration has been given to inte rconnectin g the se sources w ith the pumpe d source at perg , in an attem pt to redu ce operational co sts . Howev er it has be en found that such inter-
connection at this time is not econom ical .
After the con struc tion of the va rious ca tchwate rs , the sou rces in th is area will be ab le to meet demand for severa l years to come , and mo st p robab ly ti ll the end of the centu ry .
Th ere are the re fore no econom ic grounds for furthe r interconnect ion of sou rces to po stpone ma jor cap ital expend iture . Wh en the next sou rce is be ing considered , attention shou ld be pa id to the groun dwater po tentia l along the ban ks of the Stru le as well as to the up la nd re servoir sites .
-8 5- 7 .7 FERMAN AGH
In th is area of low popu lat ion dens ity and few grav ity sources , sma ll qu antities of water have to traverse long dista nces and are therefo re
re latively exp ensive to prov ide . Rationa lisation needs to be continued and p redominantly th is means exte nd ing the area of supp ly of the largest
sou rce , namely Killyhevlin outside Ennisk il len , by inte rconnecting it with oti/er sources , when such sources reach the limi ts of their capac ity . Two
such sou rces lie to the sou th we st and west of Killyhevlin and are shown in Fig . 7 .4 . The first , the Kil lyfo le supply , is cu rrently ov erloaded , but its initia l re lie f can more econom ically be prov ided by a pipeline connect ion w ith the Derry lin borehole wh ich is under utilised . The second , the A ltaveedan supp ly to the Clogher valley , suffers from a sho rtage of water in dry weather and has two boreholes available of lower quality water
to ac t in suppo rt . For A ltaveedan the po ss ibility exists to pipe the output of a new bo reho le at Killy faddy to the Altaveedan W orks to imp rove
its qua lity and mi x it w ith the exis ting supp lie s .
To determi ne whether th is po ssib ility is more econom ical, a
compa rison has been made between the costs of a p ipe line from the Ki llyhevlin supp ly past the Broo kebo rough rese rvo ir in the Ki lly fo le supply to Altav eedan and the costs of sep arate pipelines from Killyfaddy to
Altaveed an and from Ki llyhevlin to Brookebo rough . For quantit ies of 1.5 Ml/d prov ided to A ltaveedan and 2 .0 M l/d provided to Killyfo le , the operating costs are very similar but the cap ital costs show a sign ificant savin g by ut ilising the Killyfaddy borehole (£ 1.24 m illion against £ 0 .93 million ). The laying of a p ipeline from Ki llyfaddy bo rehole to Altaveedan
Works is the re fore more economi ca l .
-86 - MIN a a a a a a a a M I a a M O in e n a a OM
•-I 7 y Killyf addy
CW GHER VALLE Y
0
Altoveedan
Cavonocross E NNISKILLEN
LEGEND Killyhevlin -C a— Existing Source •-- New or Extended Source Brookeborougti ID Service Reservoir — Exist ing Pipeline - - - - New Pipeline
0 1 2 3 4 5 Scale Km
UPPER
(0 LOUGHt
CD Killyfole FERMANAGH 0 1 :Z) Development Options :Ds CHAPT ER 8
DEVE LOPM ENT PLANS
8 .1 INT RODUCT ION
The prev ious chapter has dea lt w ith the eco nom ic comparisons of va rious schemes w ithout considerat ion of the timi ng of such deve lopm ents . This chap te r brin gs toge ther all the asp ects invo lved in decis ion-ma king in
order to derive outline p rogramme s of development and budgetary
requ irements at 198 3 prices . Precise estima tion of the tim ing of such
developments w ill depend on regular reviews of the leaka ge redu ction
programme .
As discu ssed in Chapter 6 the tim ing of the decision to procee d with
the constru ction of a new scheme is dependent p rima rily on four factors :-
lead time requ ired for introduction of new sou rce ; (ii ) cu rrent surp lus capacity in sy stem ;
(iii ) rates of gro w th of dema nd ; (iv ) reduction of leaka ge ach ieved .
For the purpo se of deve lopin g a programm e on the basis of current informat ion, it is necessary to ma ke ce rtain assum ptions and then to mon ito r the ava ilab le indicators to see whether the correct assumptions have been ma de .
8 .1.1 Lead T ime
Th e lead time for the construct ion of a new major source haa been
tak en to be app roxima te ly sev en yea rs , consisting of two years for identification , pre lim inary design , and public enquiry two years for detailed design and land pu rchase and th ree years for construction . This time sca le can be shortened in some of its deta ils part icu larly for sma ller schemes , but it is con sidered imprudent to p lan on a much shorter overa ll period un less pa rt icu lar circums ta nce s ind icate otherw ise .
-9 7- 8 .1.2 Current Sur lus Ca acity
Tab le 8 .1 shows the capacity of ex isting sources in each of the eight
system areas , inc lud ing a llowance for capac ity to be comm issioned by 1987 . The strategic capacity is de fined as 95% o f reliab le cap acity , allowin g for an operating ma rgin as discu ssed in Section 6 .3.3 ..
TABLE 8 .1
SU RP LUS CAPAC ITY IN SYSTEM AREAS (MI/d)
Ba llymena/ Coleraine/
Antrim/ Ba llymoney/ Ma gherafelt/ Eastern La rne Moyle Coo kstown
1 includes works comp leted in 1984 and 6 Ml/d from Southern Div is ion 2 includes wo rks to be com pleted in 1984/8 5
-88- 8 .1.3 Rate of Growt h of Dema nd
Overall histo rical growth and forecast wa te r production requirement have been given in Chap te r 6 . In p lanning the tim ing of the introduction
o f new sources it is necessa ry to take ac count of the wh ole range of dema nd p ro jections . In the cu rrent situ ation where historical rates of increase
in production are greate r than fore cast rates of increa se , it is impo rtant that co ntingency p la nn ing should a llow for the high fo recast grow th rate .
Fo r each of the Div isions this rate exceeds two pe r cent pe r year for the next decade in which mo st decisions have to be taken .
8 .1.4 Reduction of Le aka e
The identified reducib le leaka ge in each system is given in Table 8 .1. In Chap ter 6 a ten year period has be en su ggested for reducing
leakage to an ac cep table leve l . The effect iveness of leaka ge programmes cannot be forecast w ith p recision , but it is ev ident that w ith sufficient resources devoted to lea kage contro l it should be po ssib le for the total water requirem ent to be m et w ithout ma jor source deve lopment du ring th is period . In view of the limit ed ma rgins current ly availab le leaka ge
reduction schemes a re esse ntia l in nearly a ll a reas and , in pa ra llel w ith th is , initiation of the development plans for new sou rces as discu sse d in
th is chap ter muet be put' in hand imm ediately .
If the rate of reduction in leakage exceeds the targets suggested , it may be po ssib le to further po stpone cap ital expend itu re . If other elem ents
of UFW , such as tru nk ma in leaka ge , can also be redu ced , this will further imp rove the position .
In the abse nce of sign ificant succe ss in leaka ge reduction the p lanned projects would have to be brought forwa rd .
8 .2 EAST ERN DIVIS ION
Planning for the developm ent of further water supp lies should be based on the fo llow ing :
Ma rgina l develop ment of existing sour ces , prima rily two po ssib ilit ies
at Dunore Po int : -99- In the shor t term , the ut ilizat ion of prima ry filtrate for filter and sand wash ing , and recovery of filter and sand wash water after sett lement , giving an extra 5M 1/d (cost £ 120 ,000 ). It is an ticipated that this work cou ld be
ope rational for use in 1986 .
b . Temporary redu ct ion of supp lies to N orthern D ivision , ma de
po ss ible by the plans for that area (see pa ra . 8 .3 below ), amount ing to perhap s 8 Ml/d . It is unlik ely that this cou ld be Imp lemented be fore 1988/89 .
The se marginal developments would a llow add itional time for the assessment of the effect ivene ss o f leakage reduct ion programmes and a sma ll measu re of additional capac ity if such pro grammes are only pa rtia lly success fu l.
Development at Glenwhir ry or Castor Bay with a capacity of aroun d 110 Ml/d . The cap ital costs of the first stages of these two schem es
invo lving only half the ult imate treatment works capa city , and de livery only as far as O ld Park Reservoir , are as fo llow s :-
Fo r G lenwhir ry 4 22 ,89 3 ,000
For Castor Bay 4 22 ,656,000
As stated in Chap te r 7 , if the treatment problems at Castor Bay can be shown to be ma nageable at reasonable cost , then secondary facto rs
indicate that the Casto r Bay solution is mo re attract ive than the Glenwhirry scheme at th is time .
Sma ll scale source deve lopment at Lough Island Reavy is attract ive ,
p rov ided th at the Mo urne Condu it is to be renovat ed . Depend ing on a detailed study of the future dema nds on the route of the conduit , and
hence the number of catchwaters wh ich wou ld be deve loped , this scheme
wou ld yie ld more than 17 M l/ d at a minimum cost of £ 15.7 mi llion .
Of these tota l costs on ly 24% a re attributab le to the increased
supplies from Lou gh Island Reavy an d the rema inder to imp roved eecu rity and quality of ex ist ing supp lies . Conside ia tion mu st be given to the necees ity and tim ing of the renovation of the Mourne
Conduit . -90- Other conclusion s have also been reached :-
The Water Se rvice is cu rrent ly considering a propo sal to iso late the
Dunore supp lies to the North ern Div ision from those to Eastern
Div ision , by constructing a sep ara te pipeline from the treatmen t
works to connect to the ex isting offtake . Such expe nditur e would not
of itse lf provide greater water resources and would require also
further treatm ent facilit ies and p robab ly a new intake . All plans for the Eastern Div ision po int to the mi nimum po ssib le utilization of
Dunore and there fore further ma rgina l dev elopmen t at th is so urce for short te rm util ization is conside red to be uneconomi c .
Th e Water Se rv ice is currently propo sing to lay a pipe line join ing
mcveighs Well , (the junct ion of the Dunore and Woodbu rn sources ) in the No rth of the city and the Mourne-Stony ford In te rconnector in the South , w ith a connect ion to Old Park Reservoir capable of be ing fed
from either direction . It is understood that the primary purpose of the northern p art wou ld be to rep lace the pipeline known as Gravity
II , which is of doubtfu l reliab ility . However it has becOme app arent
in the course of th is study that the circums tances requ iring north- south trans fe rs in exce ss of current levels are less frequent than originally thought .
8 .3 BAL LYMENA/ANT RIM/LARNE
Planning shou ld be based on :
Extending the pipe line from Dunore further north from Creavery Reservoir to supp ly Ba llyme na th rough Crebilly Reservoir . This wou ld not inc rease sou rce cap acity but wou ld imp rove distribution in the Northern Area and in the longer term ca rry w ater southw ards from Dungo nnell Re se rvoir . Th is deve lopment costing £ 600,000 could be
ope rat ional in 1986 .
-9 1- Developmen t of the Inver Dam and 1700 M I Reservoir on the.catchment
adjacent to the Du n go n n e l l Reservoir together with the further deve lopment of their comm on treatment wo rks and ou tlet pipe line to C reb illy Reservo ir . The development of some ex tra 12 Ml/d would co st
L 3 .5 m illion .
This developm ent wou ld satis fy demand until the end of the centu ry if leakage reduction measu res a re success ful . How ev er in the early years by
ope rating at full cap acity it wou ld serve to reduce the requ irement for pump ing from Du no re to Antrim and ma ke more water availab le to Be lfast to
the extent of perhaps 8 M l/d .
8 .4 COLERA INE/BALL YMONE Y/MOYLE
This area is currently supplied by two separate systems . The ma jor
scheme at Ba ll inrees outside Coleraine requires expend iture of som e £ 300 ,000 to make the current capacity more secu re by adding additional
pump ing p lant at the Bann intake for Ballin rees . This sou rce wou ld then be adequate un til at least the end of the century .
The o ther schem e , of which Altnahinch is t he largest part and which includes a number of ha w ground water source s , serves Ballym oney and Moy le and its sources shou ld be adequate until the end of the centu ry . Wh en required , the interconnection of Ba llym oney and Co lera ine with a 22 km p ipeline , co st ing £ 1.1 m illion , cu rrently appe ars to be the next most economi ca l mode of dev elopment when the sources around Ba llymoney are fully commi tted . Co n s i d e r a t i o n shou ld also be given at th at time to construction of a second dam at Altnahinch .
8 .5 MAGHE RAF ELT/COO KSTOWN
The reliab le yie ld of the ex isting sources within this area is 38 Ml/d . W ith a 5 p er cent ope rating marg in , a new sou rce wou ld require to be operating when dem and rea ches 36 M l/d . Dema nd in 1983 was 24 M l/d and the reEore th is surp lus capacity to gether w ith 4 Ml/d of reduc ible leakage w ill cater for ma ny years of increased dema nd .
-92- It is unde rstood that ma jor po llution of the River Moyo la intake
occurs not in freque ntly and that th is can be ov ercome by p rovid ing an
a lte rnative intake from Lough Neagh . Th is wou ld appear to be a sensib le
p recautio n .
8 .6 SOUTHERN DIVIS ION
In recent yea rs dema nd has required full utilisation of most of the . sou rces other than Castor Bay which has ne ither p rod uced nor been required to produce its fu ll rated output . Sufficient evidence exists that the p lant at Castor Bay w ill experience difficulty in maintaining the stat ed capacity of 68 M l/d , unless fur ther time and exp end iture are al located to : finding the be st w ays to deal w ith p rob lems of algal grow th .
Further development of treatm ent capa city and associated wo rks is recomm ended at Lough Ross (ex tra 3 Mild ) an d C lay Lake (extra 5 M I/d ) at estima ted costs of £600,000 each . Im proved interconne ct ion of sou rces between Castor Bay and Spelga/Foffany is also ne eded at an estima ted co sC of 4 300 ,000 .
In the longer term , the Caml ou gh Sour ce costing som e 4 3 .1 m illion w ith a yield o f 13 Ml/d may not be required to be ope rating un til about
199 5 . A t that time 20 km of the We st Trun k Ma in will require rep lacement at a cost of 4 1.2 mi llion to pe rm it more of the Spelga/ Fo ffany source to be used tow ards Bannbridge .
8.7 LO NDONDERRY/LIMAVADY
Examina tion of the condit ion of Altnaheglish Dam is cur rently being ca rried out by con sultants . The effect of leakage reduction on the three remed ia l programme s wh ich are under considera tion shou ld not be overlooked .
If remedia l wo rk is to be carried out to the dam without draw ing down the rese rvoir , th is shou ld be done as soo n as po ss ible for safe ty reasons ;
-93- (ii ) If rem ed ial work is to be carried out and requi res drawdown of the rese rvoir , leakage reduction wou ld lim it water dema nd and tempora ry alternat ive supp lies wou ld be mi nimised ;
(iii ) If it is decided to provide a ma jor new source it is unlikely that the ad ditiona l yield will be requ ired until the end of
the century .
8 .8 STRABANE/OMAGH
The capacity of the ex isting sources within this area is cur rently 29 Ml/d w ith approval given for the increase of Lough Bradan by 5 M l/d and
Lough Fingrea n by 6 M l/d to giv e a total of 40 M l/d . With a 5% ope rat ing ma rgin , a new source shou ld be op erating when dema nd reaches 38 M l/d .
Dem and in 1983 w as 29 M l/d , so that there is an adeq ua te margin provided th at the two above deve lopmen ts are comp leted .
8 .9 FERMANAGH
The interconnection of the Derry lin boreho le to the Killyfo le supp ly a rea to utilize an extra 2 m l/d is of great imp ortance and wou ld cost som e
£ 400,000 .
The dup lication of Killyh ev lin should be commenced in the near futu re . Interconnection of the Ki llyhevlin an d Ki lly fo le supp ly a reas by a p ipeline from Cavanacross Rese rvo ir to Brookeborough Reservoir would aw ait such dup lication .
If det ailed study of the leakage in Clogher Valley revea led little po tentia l redu ction , the development of the Ki llyfa ddy pipeline to Altaveedan would be req uired in the immediate future .
-94- 8 . 10 P RIO R ITY ARE A FO R LEA KA GE REDUCT ION
In the p re ced in g e igh t sect ions it has been shown that leaka ge re duc tio n is ur gent ly requ ired in nea r ly ev ery area if ma jor cap it a l exp end itu re is to be signi ficantly p o stponed . The a nt ic ip ated leaka ge re du ct ion requ ir es a de fined de gree of m an po w er as out lined in Ch ap ter 5 .
If on ly lim ited m anp ow er is av a ilab le to ca rry o ut leaka ge reduct ion , it wou ld be mo re econom ic a l to co nce ntrate on th e highe r prio rit y sy stems rath er than d isp erse the resou rces throu gho ut the Prov in ce .
-95- C HA PTE R 9
INFO RMA T ION FOR M ON ITO RING SUPPLY A ND DEMA ND
9 .1 INT RO DU CT ION
Th is chap te r se ts ou t a number of observa tio ns concerning the
in form ation req u irements o f Wate r Se rv ice ma na gem ent and the ab ility o f
ex ist in g sy stems to de liv er th is in fo rm atio n . It pre se nts con c lu sio n s
conce rn in g po ss ib le imp rovem en ts in the p rov is ion o f ma nagem ent in fo rm ation and co ns ide rs an ou tl ine st ructure fo r a sy stem w hich ca n eff ect iv e ly hand le the data . The ana ly s is has be en based on ev idence obta ined du ring th e co u rse of asse ss ing the wate r supp ly an d dema nd po sitio n in No rthern
Irela nd , su pp lemented by a sho rt p rog ramme of in te rv iew s w ith in form at ion u se rs w ith in th e Wate r Serv ic e .
T he invest igat io ns wh ic h have be en carr ied ou t have be e n lim it ed in s co pe . On ly in form a tion req u iremen ts re lated to ope rat ions and wa ter re sou rce p la nn in g activ ities have be en co ns ide re d . O th e r in fo rma t io n re q u i re m e nt s , no ta b ly fo r fi na nc ial ma na ge m e nt p u rp o ses h a ve not be en in cluded . Because of the inte r-re la tion sh ip be tween da ta requ irem ent s for a va r iety o f ma na gem ent a nd p la nn in g pu rp o ses , it is not s trictly app ro priate to co ns ide r managem en t in fo rmatio n fo r ope ra tions an d water resou rce p lanning in iso lat ion from these b ro ader ne eds . Deta iled re v iew o f in fo rma tio n ne eds an d p ro v isio ns fo r th e se pu rp oses wou ld itse lf re qu ire a conside ra bly m o re extensive p rog ramme o f w ork th an has be en u nderta ken fo r .th is stu dy . Du e to the se limi ta tio ns of scope an d dep th , th e p re sent a na ly s is shou ld there fo re be re ga rd ed as a bas is for d iscussio n .
9 .2 MANAG EM ENT IN FO RMA T IO N REQU IRE M ENT S
W ith in the lim its d esc rib ed above , cons iste nt , reasonab ly accu rate and re gu la rly pro duced info rma tion is requ ired by Wate r Se rvices
Ma na ge m e n t . These w ou ld inc lu de :-
-96- In the short term - control of water production
- waste control - repair and ma intenance p rogrammes
- status and alloca tion of water resources - mon itoring pe rformance again st targets
In the lon ger term
- level of service to the consum er
- co st effectiveness of water supp ly
- re source planning
- agreements on approp riate ob jectives and targets .
The frequenc ies of ma king observ at ions and co llect ing da ta w ill depend upon the pa rticula r management requ irem ents .
9 .3 WATER SOURCES
Substantia l ma nually pro cessed data are alrefdy available about each ma in sou rce to assist bo th op eratio nal and p lanning needs and such data enable safe yie lds to be kep t under review .
Inform ation from each ma jor source about re servoir lev el and output , indicat ing cu rrently availab le sto ra ge and avera ge daily draw off is transm itted in fu ll or summary form to a ll re lev ant levels of management w ithin the Prov ince , and the frequ ency of fo rms returned to Headqu arters is va ried from monthly to weekly or daily bas is acco rding to the time of yea r and occu rrence of drough t condit ions . Lo ng run historic data essentia l for forecast ing purposes is availab le for the larger sou rces .
It has , howev er , been noted that the re is an ab sence of high quality flow data from sma ll up la nd catchm ents , although the ma in reservoirs have gau ged output . It is the re fore recommended that the accu racy o f resource as sessment's should be imp roved first ly by gauging two or three additiona l sma ll up land catchm ents , and secondly by the rev iew of existing measurement of reservo ir level , draw off and sp ill for th e ma jor rese rvoirs .
-97- Rainfall data at va riou s locations throughout the Prov ince are
co llected by the Mete reologica l Office for use by the Water Se rvice and are
generally re garded as acceptab le fo r est ima ting pu rpose s . Adequate long
run data are available .
Extensive data on water supp ly are transmitted from local throu gh sub-div isional and Div isional levels to Headquarters . The extent to wh ich
the receipt of such data is eith er on the basis of "need-to-know " or forms
the ba sis for individual respo nsibility for action has not been fu lly
exami ned . A full assessment of this question wou ld req uire a detailed exami nation of the functiona l resp on sibilities o f ea ch recip ient , however , and would need to form pa rt of a more extensive rev iew .
A mi crocomputer is to be acquired by Wate r Resou rces Branch at Headqua rters and is hope d to have the capacity to ho ld data and calculate
figures for water storage , weekly draw o ff and other in form ation current ly ca lculated and graphed manua lly . This should release a substantial portion of the time currently spent on these act iv ities by scarce
professional ma npo wer resources and it is hoped that the relevant eq u ipm ent
will be ma de available as soon as po ssible . Wh ile a m icrocomp uter wou ld
ea se the present burden of calculation , it is recommended th at the overall system of co llection and transmi ssion of water supp ly data shou ld be
reviewed to avoid the risk of only piecemeal imp rovem ent to the existing
ma nagement information system .
Co nsiderat ion of water quality doe s not lie with in the scope of this study but ma jor p rob lems such as those due to a lga l b looms in Lough Neagh and tho se arising from river water quality standards do occur and it is
recomme nded that the co llection of data on these aspe cts and their possible inte gration with in a da taba se be rev iewed at the same time as any mo re
ex tensive rev iew of in format ion sy stems .
9 .4 WATER CONSUMPT ION
In con trast with the extensive info rmation availab le on the p rodu ction and supp ly of water , a marked lack of system atic informat ion is evident both at Headqua rters and elsewhe re on current water consumpt ion and on facto rs likely to influence futu re demand .
-98- 9 .4 .1 Unmete red Consum tion
Domest ic water consum ption accounts for app rox ima te ly one ha lf of
identified water consumption in No rthe rn Ireland . Because ho useho ld consumption is unmete red , it is most impo rtant that efforts continue to be made to up da te and imp rove estima tes of domestic wate r usage . The work carried out during the course of the present study on metered distr icts p rovides a basis up on w h ich such efforts can p roceed .
Survey of Metered Districts
The survey of me te red districts provides a relative ly low co st mean s o f establishing estimates of average pe r capita domestic consumption . It has the further advan ta ge of bein g easily repeatable and there fo re offe rs a good basis for monitoring chan ges in domest ic co nsumpt ion and for assessing
'the factors wh ich have brought the se about . The continuation of this exercise with meter readings on at least an annual basis is recomm ended .
Th e mete red district surveys for the pre sent study were undertaken under some p ressure of time . By establish ing a more fu lly researched framework for futu re me te red district su rvey s , it w ill be poss ib le substantia lly to imp rove the quality of data in fu ture . The select ion of a wider variety of districts and inclusion of a grea te r number with a mo re rep resenta tive p rop ortion of public sector ho using is part icu larly desirable .
In order to exped ite the exerc ise a simp lified form of the household qu est ionna ire used for the p resent study should be develop ed to be used when a district is init ia lly set up and from tim e to time the rea fte r (say every four to five years ). Ln intervening yea rs it w ill be adequate to update only household and popu lat ion figu res , possib ly usin g forms for self-completion by ho useho lders . Becau se indiv idual househo lds w ill be surveyed on a regu lar and repe ated basis , it may be app ropriate to offe r a sma ll consideration to househo lde rs for taking part .
-99- It is suggested that consumption metering in metered districts
should be ca rried out more frequ ently than the househo ld survey . This wou ld provide additional informa tion concernin g , fo r example , sea sona l
variations in dom est ic demand and the imp act of water rationing measu res
du ring pe riods of sho rtage .
Fu ll Hou seho ld Survey
More ex tens ive information concerning changing pa tterns of oWnersh ip
and use o f domestic wa te r-using app liances ma y be obta ined by the
occasiona l repetition of the full household survey undertaken for the present study . Rep etit ion of this exercise on a fiv e-yearly basis is
suggested , althou gh the actua l frequ ency should be dependent on a range of
factors including the resu lts ev ident from the metered districts exercise and the prevailin g ba lance of supp ly and dema nd .
Up -to-date est ima tes of dom est ic water consumption may be ob ta ined by
comb inin g the resu lts of the metered district s exercise with updated cen sus inform ation conce rn ing su ch facto rs as popu lation , househo ld numb ers and
hou seho ld size com po sition . It is suggested tha t such estimates should be ca lculated at least annually for each sub -div ision .
9 .4 .2 Mete red Cons tion
Data ha ndling
At pre sent all non-domestic consum ers conside red likely to consume over 100 ,000 litres in a six month ly period have a m eter insta lled and the
to tal expe cted revenue in 1983/84 is £8 .8m . Meter rea dings obtained on a
six month ly cy cle are used to ca lcu late water cha rges and are po tentia lly a subst antia l source of reliab le consumption data for planning decisions at
Headquarters and Divisional lev el . However , becau se the p resent meter data
feed a sy stem designed sole ly for accounting and billing pu rpo ses , both the details from the reco rds and the ana lysis of the data are inadeq uate for monito ring curient consumpt ion patt erns and forecas ting futu re dem and . The quality of da ta reco rds , the ir accessibility and their use fulness for operationa l and p lanning purpo se s represent a cause for con cern .
- 100- A more fundam ental problem is that a full register of me te r ho lders does not ex ist and there app ea rs to be no systematic m eans of keep ing such
a list up to date . Wh ile there has been a substantial increase in the num ber of metered consumers (from 47,000 in 1973 to 64 ,000 ten yea rs
later ), there app ea r to be po tentia l gap s in the tran smi ss ion of in forma tion about new consum ers . For examp le , though p lann in g app lica tions
co ntain details on new developm ents , informa tion m ay not be pa ssed from Div isional level to the meter inspec torate . Similarly , notificat ion of
disconnection is left to the indiv idua l meter inspecto r , as is the identification o f non-registered large-scale water users . Th is situ at ion
must also raise qu estions abo ut the effect iveness of revenue estimat ion and
co llection .
Ev idence provided during the course of this study ind icated that there is significant under-reg istration of con sump tion by a p rop ortion of trade mete rs , pa rt icu larly at low 'trick le ' flow levels . It is not po ss ible to assess satisfactorily the ove rall volume of un recorded
consumption due to th is cause without furth er informa tion concern ing sizing
of meters and patterns of consumption by m etered users (in terms of the propo rt ion of consump tion taking pla ce at low flow levels ). It is su ggested that th is subject shou ld rece ive further at tention w ith a view to develop ing the mo st economical meter rep lacement po licy and to obtaining
more reliable consumption figu res . Imp roveme nts in th is area shou ld also have a direct impact on rev enue , po ssibly amoun ting to a total of £8 00,000 per annum , and w ou ld there fo re be self financin g.
Th e method of data collect ion adopted in the Region app ears unne cessa rily comp licated . The tw ice-y ea rly "merry go round" of con sumer
index cards from Wate r Charges Branch , who handle the data , to local level for comp letion and back again must invo lve a high risk of loss or m islaying
of record s .
The index cards thems elves are the so le sou rce of vital trend data in consump tion often go ing back over ten yea rs . Such data a re not held on the bu reau 's comp uter files beyond 18 months or 2 years and consequent ly information on consump tion patterns can only be established by lengthy exam ination of the manua lly co llected meter ca rds . Th is assumes th ey can first be found and then abstracted from the system w ithout disruption to
- 10 1- the revenue generation procedu res . Maintenance of the se records on archive comp uter fi les shou ld invo lve a ne gligible add it ional exp en se which wou ld
repay itself by providin g a much needed data sou rce for feasib ility eng ineers at both Div isio na l and Headquarters leve ls .
One app roach to the calculation of current water consumption adop ted
in th is study w as to estima te the consumption p atterns of a se lected samp le
of metered consum ers . In attempting this it was found that the me ter card s we re o ften inadequate ly re ferenced and that they are catalogued by Water
Charges Branch on a basis which bears litt le or no relation to the rou nds
of the inspe ctors . Th is resu lts in unnecessary clerica l effort to reso rt and 'reclassify .
Given the unavo idab le di fficult ies with handling manual records , and the desirab ility of rem oving unn ecessa ry clerical inputs , it is su ggested
th at the fo llow ing should be conside red :-
(a ) the use of self-comp letion fo rm s by the consum er , perhaps on a more frequent basis than 6 mon th ly ; or
(b ) in the longer term 'the introdu ct ion of computerised inte grated instantaneous meter reading-billing system s .
Data classification
The above pa ra graph s describe the ope rationa l prob lems with data captu re . Ma jor p rob lems on the classification ma te rial used on the cards were also iden tified wh ich lim it their use for plannin g purposes . For example , while there is a very broad ind ication of the type of con sum er
such as ag ricu ltura l, industrial or service sector , the classificat ion does not allow dema nd to be analysed by more deta iled industry groups and as a resu lt exam ination of trend s in the pattern of wate r use by , for examp le , the engineering or text ile sub-sector is imp ract icab le .
- 102- The geo graph ica l or locat ional information is also very limi ted .
Cards are stored acco rd ing to mete ring d istricts (wh ich do no t ma tch the rou nds of mete r reade rs ) and only addresses are sto red on the computer file w ith no allocative p rocess, so that analysis of consum ption by area is impo ss ible . This is known to have cau sed considerab le difficult ies in ca rry ing out waste mete ring exerc ises .
At present the full potentia l usefu lness of me te r records for operational and p lanning purposes is not be ing realised . The type of ma na ge rial plann in g informa tion wh ich is requi red would cover for example :-
(a) historical consump tion by indu strial sector ;
(b ) geograph ical analy sis of consumption by sector .
Th is could be achieved by :-
(i ) The use of mo re extensive and accurate cod ing Of the indust ry of the consum er . Standard Industria l Cla ssificat ion is recomm ended and some
train ing for tho se completing cards would be essent ial to ensu re consistency of ma te rial .
(ii ) The use of sma ller geo graph ical areas , wh ich wou ld enable en gineers
to iden tify metered users and custom ers in indiv idual waste mete ring
dist ricts .
(iii ) Ret ent ion of data on com puter fi le beyond two years to pe rm it trend s to be ca lcu lated .
Additional uses of data
The potentia l operationa l uses of the data cou ld also be expanded in the fo llow ing ways :-
(a ) Alth ough the computer based reco rd conta ins details of the me ter type , numb er and its age , th is informa tion is not used in the
pro gramme of planned maintenance of mete rs . G iven that there is a five y ear ro lling pro gramme of rep lacem ent of meters , then the
- 103- database shou ld be used as a basic managem ent tool . Th is is
especially important given the like ly unde r- reco rding of a large numbe r of existing o lde r meters and the co nsequen t lo ss o f revenue .
(b ) If the indiv idual users cou ld be defined in re lation to their
po sition in the distribution netwo rk as well as being known by the ir geographical location , it wou ld perm it easy identification o f consume rs who wou ld be affected by ma intenance work .
In the course of the survey of ma na gem ent inform ation needs, it emerged that some expenditure wa s likely on new developments in the
softwa re for ca lculation of water charges . It is unde rstood that th is
would be design ed to imp rove credit control , spe ed up qu eries , increase
sto rage capacity , and give more flexibility in outpu ts . Wh ile th is wou ld certainly bring an imp rovement to the present situation it is suggested
that more thought be given to improveme nts in the cove rage and quality of the basic database and to the system of collection of data . Improvem ents
in the p rese ntation of data , when the data a re incomp lete or not use ful, to ma jor pa rts of the organ isat ion wou ld not , in fact , bring a net gain to the
Wate r Se rvice .
The overa ll requ irement is there fore for a system which is or iented towards the timely p rovision of informa tion for operational and p lanning needs as we ll as ac coun tin g requireme nts . It is like ly this can be ach ieved only if there is some integration of engineering management , water cha rging and financia l information arrangements .
9.4 .3 Use of ex ternal in forma tion sources
Wh e re regu lar informa tion is available from elsewhere such as from the Census or the Continuous Househo ld Survey or other econom ic and soc ial statistica l sources , there hav e been no re gu lar arrangem ents made to analyse factors of particular re lev an ce to the water indu stry .
Starting from the most ag gregated form of informa tion gathering to p rovide estimates of futu re demand , it is suggested th at a reliable da tabase of broad regional economi c and social informationbe estab lished
- 104- and up-dated at regula r intervals by Water Se rvices Headqua rters . An extensive list of the type of data necessary for such st rategic p lanning purposes is set out in Table 9. 1. As a m inimum , upda ted census records of popu lation and household characte rist ics (includ ing analysis at sub- div ision level ), reco rds of trends in employment , industria l patterns and agricu ltu ral act ivit ies shou ld be co llated and rev iew ed re gularly . The
Water Se rvice does no t at pre sent have enou gh of the spe cialist sk il ls necessary to establish , maint ain and interpret such data records . If succe ss is to be achieved , it will be necessary for these skil ls to be obtained, eith er by recru itment or by outside ass istan ce , po ss ibly from the specialist resour ce s availab le elsewhere in the Northern Ireland Civ il
Serv ice .
On a more loca l level , it is suggested that furthe r con sideration shou ld be given to the way in which loca l au thority development p lanning info rmation (affecting both dom estic and non-domest ic use ) is tra nsm itted to the Water Se rvice at Div isional Level and beyond . Wh ile draina ge and sew erage serv ices may prese nt bigger problems at prese nt than prov ision of water supp ly to new developments , there appea rs to be no formal mechan ism to collect and co llate data on forthcomi ng changes to help make jud gem ents on the balance betw een available supp ly and new development demands .
9 .5 UNACCOUNT ED FOR WATER/LEAKA GE CONT ROL
Substantia l e ffort has been put in by all Div isions on wastew ater mon ito ring pro grammes in the various waste districts . Considerab le information is ma nually co llated and transmitted throughout the system .
Howeve r , pa rtly because of a lack of resources , continuous waste control p rogramm es have not yet been established . There is also considerable variation in the extent of waste measurement among the Div isions .
Some part icu lar aspects were highlighted in the oourse of th is study :-
(a ) the freq uency of monitoring of waste me ters varies and the range of in forma tion co llected such as minimum night f low an d 24 hour flow s seems .to vary :
- 105- (b ) the quality of trunk ma in me te ring requi res improveM ent:.
(c ) was te management must be acco rded a higher p riority for action in
a ll areas .
9 .6 COM PUTER FAC ILIT IES
Som e of the issues raised in this Ch apte r are closely related to the
imp ortan ce of imp roved communications and more extensive use of computing facilities . The lack of such facil ities in the Water Serv ice at
Headqua rters and Divisional level is ev ident as is the po ss ibly more crucial absence of staff with experience of use of such facilities . It is likely th at a sub stant ial learn ing period and training input wou ld be requ ired to enhance the sta ff capabilit ies .
There are pa rticu lar p roblems arising from the lack of computer facilities direct ly accessible to Water Services Headqua rters :-
(a) Op erational models cannot be directly used by Water Serv ice sta ff . Th is considerab ly reduces their ab ility to expe riment with different
op erating strategies or to extend and develop mod els as required . There are also cost disa dvantages .
(b ) There is no facility for the Water Se rvices to develop computer
mode ls needed for dema nd estimation and forecasting .
(c ) The Wat er Service does not have access to an adequ ate database system .
Th ere is , the refore , a strong prima facie case for the acquisition of computer facilities in the context of a more ex tensive review of info rma tion . Care fu l co nsideration is needed , howeve r , before any particular op tion is se lected . It will also be important to rev iew existing ma nagem ent informa tion systems and to make sure that any comp uterised system does no t simply rep licate the inadequ ac ies of the existing manu al clerical system in a more techn ically sophisticated way .
- 106- 9 .7 SUMMARY
In contrast with the Regional Water Authorities , there has be en
relatively little p ressu re on the NI Water Se rvice to p rodu ce a co rporate p lan , to meet financial and cost pe rforma nce ta rgets or to prod uce annual rep orts and acco unts , a ll of wh ich require extensive non -financial as w ell as finan cial database s for managem ent Informat ion . Development of performa nce ind icators for various aspec ts of the se rvice is not apparent and there have pe rhap s not bee n the equivalent discu ssions on target levels . of se rvice for the consumer .
Recent work on ma npower , productivity and the relative costs of ou tpu ts undertak en for the Water Serv ice has shown the usefulness of m ore ex tensive and integrated financia l and non-fina ncia l data .
A ll th is points to a greater need :-
(a) to clar ify managem ent informa tion requ irements ;
(b ) to provide a mo re deta iled breakdown of in forma t ion wherever po ssib le ;
(c ) to imp rove accuracy o f data collection ;
(d ) to ensu re sy stemat ic transm ission of information to those who need to
kn ow and are required to take action on the basis of the
information ;
(e) to provide appropriate computer facilities .
- 107- TAB LE 9 .1
SOC IAL AND ECONOM IC STAT IST ICAL RE QU IREM ENTS
(a ) For domestic consumption est imation/ forecastin g
Item Sou rce Household characte ristics Censuse s of popu lat ion and upda tes - ho useho ld numbe rs
household popu lation
- househo ld size distribu tion - household tenure distribut ion
- rooms per househo ld re
- household income Hou seho ld surveys , Genera l Household Survey , Family Expenditure Su rvey Household am en ities
ba th s/show ers Household surveys
- inside W .C . p lus census of
- outside W .C . popu lation where connec tion to public supp ly app licab le - wash in g mach ines , dishw ashers , Househo ld surveys
garden hose , etc .
(b ) Fo r non-dom estic oonsumption estimation/ fore casting
Item Source Agriculture - numb er of farm estab lishm ents Agricultura l
livestock numbe rs Censu s
Industry , Comm erce , Other - numbe r of establishm ents by Census of
secto r Emp loyment - emp loyment by sector
size distr ibutio n of establishments by secto r
output by indu st ry secto r Censu s of Production ,
(regiona l) Nationa l Income Statistics - 108- • • • M I N O I S S O I N M O M • MO M • Ile M I OM M I S IS •
TAB LE A 1.1 APPEN DIX 1
EASTERN DIVISION CURRENT CAPAC IT IES OF SOURCES
Ml/d
Type Basic Prescribed Process Losses Effective Notes Y ield F low Water Yie ld
Dunore Po int L 136 .0 118 .0 18.0 to North ern Woo dburn System I 45.9 1.8 44 .1 Silent Valley System I 112.8 112 .8 Lough Is land Reavy I 30* I 15 .9 1 (Max ) 18 .0 -• Lough Cowey L 4.1 0 0 .2 3.2 (1) ko Ba llysa llagh/Conlig I 9.9 0.6 1 0.4 8.8 (1) Ho lywood Reservo irs I 3.4 0 .1 0 .2 3.1 Portavoe I 2.9 0 .1 2 .0 ) Lough Mo ney/Tannaghmore L 1.35 1.35 ) 4 .0 (/) Ki llough I 0.7 0.7 ) Boomers L 1.8 0 .1 1.7 Stoney ford/Lea thermstown I 25 .5 5 .7 1.0 1.8 14 .8 (1) Castor Bay (Ma gheraliskmi sk ) L 6 .0 From Southern Wh itehead B 0.24 Ballycu llen/Comb er B 11.40 1 Lisburn Borewe lls B 2.03 1 De rryaghy B 1.12 12.0 1982 Production Lagan Va lley Boreho les B 20 .0 Expe cted Prod uct ion by 1987 366 .5
No te (1) Capac ity limi tations • W M SIM In In In In • M I a n N M M O MS
TAB LE A 1.2
NO RTHERN DIVISION CURRENT CAPAC IT IES OF SOURCES Mild
Type Basic Prescribed Process Losses Effe ct ive No tes Yield Flow Water Yield
Dunore Point L 18 .0 From Easte rn Killylane I 14 .6 0.6 - 1.0* 13 .0 *Afforested Ca tc hm ent Dungo nnell I 13 .0 0.5 0.6 11.9 Quo lie I 5.2 0.2 5.0 Lough Fea L 13.8 0.6 13.2 Ba llinrees and River Bann R 33 .5 1.4 33.1 (1 ) Altnahinch I 14 .5 3.2 0.6 10.7 Moyo la R 13.0 Alternative inlet Sa llagh Sp rings s 1.27 requi red G lebe (Glenarm ) S 0.18 ) Bonnytobe r $ 0.23 ) • Straidk il ly S 0 .90 ) Garron Point S 0.18 ) St . Cunn ing S 0.30 ) Tobe rterin s 0.68 ) Pome roy S 0.35 ) Montober s 1.86 ) Kn ocklayd S 1.10 ) Fo riff S 0 .28 ) Ba l lyemo n s 0.30 ) Waterfoot S 0.13 ) Fa rrantemp le s 1.00 ) Mo ydaml aght s 2.04 ) 10.8 Cu rrent y ie lds G larry ford Boreho les B 8 .45 ) Buck na Boreholes B 2.40 ) Drumbe st Boreho le B 4.40 ) Alcrossa gh Boreho le B 2.05 ) Droma in Bo reho le B 1.00 ) 18 .3 Cur rent dry weather y ie lds 147.0
Note (1 ) Capacity limi tat ions • a a • ON • • IN • IS M a • M I • IN I • M I M I 11111 •
TAB LE A 1.3
SOUT HE RN D IV ISIO N CU RRENT CA PAC IT IES O F SOURC ES Mild
Type Bas ic Pre sc ribed Pr ocess Los se s Effe ct iv e Notes Yie ld F low W ater Yie ld
Seagahan I 16 .3 1.2 0.6 14 .5 A ltmo re I 3.6 0 .2 3 .4 C lay Lak e L 10 .3 9 .3 (Ma x ) 2 .0 (1 ) Ba lly lane Lake L 1.2 0 .9 (1 ) Wash in g Bay L 0.9 0 .9 Castor Ba y L 72 .6 2 .9 63 .7 6 .0 to Ea ste rn Sp elga/ Fo fann y I 28 .0 2 .8 1. 1 24 .1 Lo u gh Ross L 4 .1 (1 ) Lo u gh Is land Reavy L 1.2 Cam lou gh L )_ 2.2 1 Ba ll intemp le I ) I 3 .2 (1) C lo gh in ny R )_ 1.0 I 7 C lont y gora ) Le it rim R - C ro tliev e/ Ye llow Water R 1.0 (1) Ki lfe aghan R 1.4 1.4 Min . Rive r Flo w A tt ica l R 1.2 Tu lly ard B 2 .39 No t use d Sh anm oy B 5 .20 Go rt le na gh an B 1.94 Dick son 's Mi ll B 0 .38 Ca bra gh B 1.73 9 .2 1982 Pr oduction Glenorn W 1.32 1 .3 13 2 .1 11. 1 1 11. 1 1. 1 O N a n a a . 11 1 1 . 1. a a 0 . TABLE A 1.4
WESTERN DIVIS ION CURRENT CAPACIT IES OF SOU RCES Ml/d
Typ e Basic Pre sc ribed Proc ess Losses Effect ive Note s Yield Flow Water Yield
Ki lly fole L 7.3 4 .5 (1 ) Ba llydoolagh Lough 2 .3 (1 ) Doagh Lough 0.2 Killyhevlin L 11.4 0.5 10.9 (1) Muckros 1.6 To be abondoned Altnaheglish/Rive r G lenedra I (15.4 + 7.3 ) 18 .0 Ki llea I 1.1 1.1 Lough Fingrean/LOugh Ma cro ry 13.0 ) Including cur rent Lough Bradan 8 .4 ) ex ten sionds G lenco rdial + R . Camowen I 4 .5 0.2 4 .3 (1) Ev ish/Knockhavoe 2 .0 Be lleek R 2.2 0.9 Dem and limi ted Al taveedan 2 .7 (1) Clo ghole (Carmoney ) R 34 .8 34 .8 Riv er De rg 13.0 (1) Larganacarron B 0.18 ) Augher B 0 .22 ) Favour Royal B 0.84 ) Ummera B 0 .61 ) Dem and lim ited Brishey B 1.04 ) Culmore B 0.13 ) 3.4 1982 Prod uction Ma rble Arch S 3.75 Wellglass/Gortco rbies S 2 .51 Al tamoo skan S 0.10 Sixmi lecross S 0.04 Lenam ore S 0 .33 New town stewart S 0.21 Dunnaman agh S 0.15 7.1 1982 Production
NOTE L - Lough R = R iver W = Well I = Impound in g Rese rvo ir B = Borehole S = Spring APPEN DIX 2
NON-ENUMERAT ED POPULAT ION
TAB LE A2 .I
Belfast 327 200 295 223 3 1 977 10 .8
Cookstown 29 600 26 624 2 976 11.2
Dungannon 45 600 4 1 073 4 527 11 .0 Londo nderry 92 700 83 384 9 3 16 11.2
Maghera fe lt 33 800 30 825 2 975 9 .7 New ry & Mourne 78 700 72 243 6 457 8 .9
Omagh 46 300 4 1 159 5 14 1 12 .5
Strab ane 37 000 35 028 1 972 5 .6
Other 87 1 300 862 518 8 782 1.0
North ern Ireland 1 562 200 1 488 077 74 123 5.0
- 113- TAB LE A 2 .2
NON -EN UM E RAT ED POPUL AT ION BY SUB DIV IS ION
E st im ated Non -enum erated
Pop u lat ion as % o f
Su b div is ion Enum era te d Po u lat io n
An trim 1.0
Ba llym ena 5 .8
Co lera ine 1.0
NO RT HERN 2 .9
Arma gh 6 .5
C ra igavon 1.0
New ry 6 .7
SO UT HERN 4 .9
Be lfast 8 .0
Downp a trick 1.0
L isb u rn 1.0
EA ST E RN 5 .2
Enniski lle n 1.0
Londonde rry 8 .9
Oma gh 9 .4
W E ST ERN 7 .2
NO RT HERN IRELA ND 5 .0
- 114- M I • ON • • • • a l • S I • M I M I • • • a i n •
APPENDIX 3
POPULATION GROWTH
TABLE A3.1
POPULATION PROJECTION BY SUBDIVISION (HIGH GROWTH)
1 Growth Factor
1981 NI Census Figures Adjusted for estimated non-enumeration. MS • 0 • • IS 1113 I NS I S MS • a I III I IS M II• 1 • • M S •
APPENDIX 3
POPILATION GROWTH
TABLE A3.1
POPULATION PROJECTION BY SUBDIVISION (HIGH GROWTH)
Population in 1 Growth Factor Private Housholds 1981 000s 1981 1985 1999 1995 2000
Eastern Division Bel fast 447.6 1.000 1.007 1.029 1.055 0.965 Downpatrick 155.9 1.000 1.058 1.146 1.245 1•386 L isbUrn 121.8 1.000 1.073 1.172 1.245 1.411 725.3 1 fr. Northern Division fr . c-, Antrim 86.2 L OGO 1.026 1.071 1.122 1.216 1 Sal ynena 117.8 1.000 1.043 1.101 1.162 1.304 Col era i ne 83.1 1.000 1.022 1.058 1.097 1.126 287.1
Southern Div i sion Armagh 79.9 1.000 1.027 1.069 1.115 1.226 Craigavon 772 1.000 1.048 1.093 1.130 1.229 Newry 107.7 1.000 1.022 1.064 1.113 1.298 265.4
Western Div i sion Enniskillen 57.7 1.000 1.027 1.073 1.126 1.229 Londonderry 116.9 1.000 1.026 1.069 1.117 1.102 Omagh 82.4 1.000 1.037 1.107 1.190 1.302 257.0
1981 NI Census Figures Adjusted for estimated non-enumeration. 0 1 • • • • ON • IS IS • • OM • a a a • 1111 •
TABLE A3. 2
POPULATI ON PROJ ECTION BY SUBDI VI SI ON (MI D GROWTH)
Popul at i on i n Gr owt h Fact or Pr i vat e Noushol ds 1981 1000s 1981 1985 1990 1995 2000
East er n Di v si on Bel f ast 447 .6 1.000 0 .993 0.991 0.995 0.891 Downpat r i ck 155.9 1.000 1.043 1. 104 1.175 1.291 Li sburn 121.8 1.000 1.059 1. 129 1. 188 1.303 725.3
Nor t her n Di vi si on Ant r i m 86.2 1. 000 1.012 1.031 1.058 1.123 gal yinena 117.8 1.000 1.029 1.061 1.096 1.205 Col er a i ne 83. 1 1.000 1.008 1. 019 1. 035 1.041 1 287.1 I- 1-• -4 i Sout her n Di v i si on Armagh 79.9 1.000 1.013 1.029 1.052 1.132 Cr ai gavon 77.8 1.000 1.034 1.052 1.071 1.135 Newr y 107. 7 1. 000 1.008 1.025 1. 050 1. 199 265.4
West er n Di v i si on Enni sk i l l en 57. 7 1. 000 1.013 1. 033 1. 063 1.200 Londonder ry 116.9 1.000 1.012 1.029 1.054 1.019 crnagh 82.4 1. 000 1.023 1. 067 1. 123 1.203
1981 NI Census f gur e s adj ust ed f or est imat ed non- enumer at ion. M I • 0 0 NM W e M I M I NN • • N B a • M I
TABLE A3.3
POPULATION PROJECTION BY SUBDIVISION (LOW GROWTH)
Population in 1 Growth Factor Private Housholds 1981 '000s 1981 1985 1990 1995 2000
Eastern Division Belfast 447.6 1.000 0.982 0.964 0.956 0.846 Downpatrick 155.9 L OCO 1.032 1.073 1.127 1.216 Lisburn 121.8 1.000 1.048 1.098 1.140 1.238 725.3
Northern Division Antrim 86.2 1.000 1.001 1.003 1.017 1.067 Balymena 117.8 1.000 1.018 1.031 1.053 1.144 Coleraine 1 83.1 1.000 .997 0.991 0.994 0.989 I-• I- 287.1 w 1 Southern Division Armagh 79.9 1.000 1.002 1.001 1.011 1.075 Craigavon 77.8 1.000 1.023 1.023 1.028 1.078 Newry 107.7 1.000 0.997 0.997 1.008 1.139 265.4
Western Division Enniskillen 57.7 1.000 1.002 1.005 1.021 1.140 Londonderry 116.9 1.000 1.001 1.001 1.013 1.967 Omagh 82.4 1.000 1.012 1.037 1.077 1.142
1981 NI Census figures adjusted for estimated non-enumeration. I S S I Ol I l a - 0 M U M M a • • M I a 0
APPENDI X 4
RATER CONSPVTI ON TABLE A4.1 BASE YEAR (1981) WATER CONSIAVTI ON BY CONSMER CATEGORY
Sub- 0 vi si on Domest i c Aqt: i cul t ur e I ndust ry Conmer ce Const ruct i on ocher Agr . . »ea sehol d Oper at i ons Met er Err or Tot al
NOTE: Er r or s i n addi t i ons due to roundi ng. APPENDIX 4
WATER CONSUI4'TI ON PROJECTIONS TABLE A4.2 WATER CONSUM,TI ON PROJECTIM S BY DIVI SION AND BY CONSLOPTI ON CATEGORY (M1/0)
- 120 - WATER CONSUPPTI ON PROJECTI ONS TABLE A4.2 (cont ) WATER CONSUI4 TI ON PROJECTI ONS BY DIVI SION AND BY CONSUMPTION CATEGORY (10/ 1))
- 12 1- WATER CONSUMPTION PROJECTI ONS TABLE A4.2 (cont ) WATER CO8510471014 PROJECTI ONS BY DIVISION AND BY CONSUPPTION CATEGORY ( 41/ 0)
- 12 2- WATER CONSWPTI ON PROJECTI ONS
TABLE A4.2 (cont ) WATER CONSLOPTI ON PROJECTI ONS BY DIVI SION AND BY CONSIOPTION CATEGORY (MI/ D)
Base (1981) 1983 1485 1990 1995 2000
WESTERN DIVI SION
Domesti c High 36.8 42 .5 49 .0 55.3 Mid 32.1 33.7 35.2 38.4 41. 7 44.8 Low 34. 0 36 .2 38 .3 40 .3
Agr i cul t ur e High 11.1 11.4 11.8 12.1 Mid 10.9 10.9 11.0 ILI 11.2 11.3 Low 10.8 10.7 10. 7 10.6
I ndust ry High 6.8 7.4 8. 1 8 .9 Mid 6. 7 6. 7 6. 7 7.1 7.6 8.2 Low 6.5 6.8 7. 1 7.5
Conner ce High 1. 6 1. 7 1. 9 2.1 Mid 1. 6 1. 6 1.6 1. 6 1. 7 1. 7 Low 1. 5 1.5 1. 5 1.4
Const r uct i on High 0 .9 1. 0 1. 0 1. 1 Mid 0 .9 0 .9 0 .9 0 .9 0 .9 0.9 Low 0 .9 0.8 0 .8 0 .8
Other Hi gh 5.8 6.6 7.9 8.4 Mid 5.6 5 .6 5.8 6.2 6.7 7.3 Low 5. 7 5.9 6.0 6.2
Agr i cul t ur al Hi gh - 3. 2 -3 .6 -3. 9 -4 . 1 Househol d Mid -2.9 -3.0 -3.1 -3.5 -3.6 -3.7 Usage Low - 2.9 - 3.3 - 3.3 -3. 3 operat i onal High 3. 3 3. 7 4. 1 4.6 usage Mid 3.0 3. 1 3.2 3.4 3.6 3.8 Low 3. 1 3. 2 3. 3 3.5
Adj ust ment f or Hi gh 2.6 2.8 3.0 3.3 meter er ror s Mid 2.6 2.6 2.6 2. 7 2.8 2.9 Low 2.5 2.6 2.6 2. 7
TOTAL High 65.7 73.4 82.9 91.6 Mid 60.4 62.0 63.8 67.9 72. 7 77. 3 Low 62.2 64.4 67.0 69.7
- 1 23- WATER CONSUWTION PROJECTIONS
TABLE A4. 2 (cont ) WATER CONSUMPTION PROJECTIONS BY DIVI SION AND BY CONSUMPTI ON CATEGORY (M1/ 0)
- 1 2 4- A PP EN D IX 5
EC ONOM IC ACT IV ITY P RO JECT IONS
5 .1 INDU ST RY A ND C OMM ERCE
Forecast s o f no n -dom est ic water co nsumpt ion have be en ba sed on p ro jecte d m ovem ents in app ro p r ia te activ ity in d icato rs . Tab le A 5 .1 show s
th e centra l assum ptio ns wh ic h ha ve be en made fo r th e pa th of grow th of th e
No rthern Ire la nd Econo my fro m 198 3 to the tu rn of the centu ry . A lso shown
a re offic ia l est im ates of cha nges b etween 198 1 (th e ba se -y ear for th is
stu dy ) and 198 3.
TABLE A 5 .1
In orde r to ta ke ac coun t of unce rtainty , a ran ge .of va lues has be en assum ed abo ut the cent ral p ro ject ion shown in Tab le A 5 . 1. Tab le A 5 .2 sh ow s th e ran ge exp ressed in te rm s of to ta l pe rcenta ge grow th from 198 3 to 2000 .
- 12 5- TAB LE A 5 .2
RA NG E OF G ROWTH PRO J ECT IONS OF N .I . ECONOM IC VARI AB LE S
T ota l Pe rce ntage In cre ase (Decrease )
198 3- 2000
High Mi d
Indus tria l Ou tp ut 40 29 18
Th ese ec onomi c assump tio n s have be en made in the li ght of exp ectations conce rn in g the lo ng term deve lopm e nt of the UK e con omy taken a s a wh o le . Th e fo l low ing assu mp tio n s have been mad e fo r th e pa th of grow th of th e U K economy: -
TAB LE A 5 .3
MAJ OR NAT IO NAL EC ONOM IC VAR IAB LE - A NN UAL PE RC ENTAGE G RO WTH
198 3/ 84 to 2000/ 0 1
- 12 6- 5 .2 AG RICULTURE
Crop irr igation from pub lic supp lies is insign ificant in the Province and not expe cted to increase . The ma in determi nants of farm water consumption (exc luding farm dome stic use ) are therefo re the vo lum e and 'mix of livestock together w ith tech niques adop ted fOr husbandry .
Th e assumpt ion s wh ich have been made conce rn ing growth in livestock numbe rs are shown in Tab le A 5 .4 . The m id and low grow th paths in relation to the numbe rs of pigs reflect the like lihood of increasing foreign comp et ition in th is ma rk et . W ith the lev el of financ ial supp ort for the cAp under rev iew the growth pro ject ion s show n in Table A5 .4 may be op tim istic .
TAB LE A 5 .4
G ROWT H IN LIVE STOCK NUMB ERS IN NORTHERN IRELAND 198 1-2000
1 Source 198 1 Agricu ltura l Census .
- 127- M a l° MIN a l• • 0 1 10 0 • 1• O NIO NS ONI O NI S APPEND IX 6
ELA ST ICITY OF DEMAND
6 .1 G ENERAL
Informa tion con ce rning the sensitiv ity o f water consumption demand to chan ges in p rices o r to changes in income/output is desirab le both for forecast ing purposes and to assess the impa ct of po licy measures on consumption . Very little evidence is av ailab le on th is subject , howev er .
Th e qu a lity of consump tion data collected in No rth ern Ire land is not adequate to pe rm it the imp act either of p rices or of incom e/output to be p roperly assessed .
Da ta availab le from sources outs ide the Province could prov ide an alternative bas is for estima ting dema nd elastic ities . In ge neral this informa tion too is of limi ted use , how ever , since detailed con sumption figu res for the domest ic and non-domest ic sectors have only recently be come availab le so that it is not po ssib le to calcu late long- run elast icities . The poor quality of available data ma kes it very d ifficu lt to separate income and price effects from the imp act of clima tic variation , techno logical de ve lopment or imp roveme nts in standards of hygiene .
Ev idence available from othe r studies suggest s that there are ma rked d ifferences between the dome st ic and the non-domestic sec tors . Where . water is charged for acco rding to use in the dom estic sector , consumption app ea rs to be relatively insens it ive to price variat ions . Non-dom estic dema nd (in part icu lar indu stria l consumption ) appears to vary considerably both with ou tput and w ith p rice .
- 128- • OMI IM IS MI N = M e g a IM OIN IO N11 11111 1= N O 6 .2 DOMEST IC WATER DEMAND
6 .2.1 Price E laat ic ity
UK h o u s e h o l d s are not charged directly for their water oonsumptio å so that it is not po ssib le to estima te any price elast icities . Rises in water rat es lev ied by the Wat er Au thorities are generally deemed to have no no ticeab le effect on dome stic water consumption . Th is is to be expected , since the amount consumed by an indiv idua l househo ld has no direct impact on exp end itu re irrespective of the level of water rate .
Expe rience in countries wh ere domest ic dem and is me t e r e d suggests that , desp ite short term redu ctions immmedia tely after the imp osition of p rice inc rease s , the lon g term dema nd is almost price insensit ive and that only m inor reduc tions in water dema nd (pa rt icularly in the use o f sprinklers , and garden hose s ) could be achieved t h r o u gh price increases (Gu nderma nn 1983 ).*
Re ferences at the end of this Appe nd ix ).
6 .2 .2 Income E lasticity
Income changes affect water dem and ind irect ly t h r o u g h their effect on housing stock , availab ility of am enities , app liance own ersh ip and socia l structure . Since these changes take place very slow ly and reliab le estimates of t he domestic water consump tion in th e UK are only availab le for recent years , there is very litt le informa tion on the long-te rm effects of increased h o u s e h o l d income on water dema nd . In Ge rm any , where dom estic consumption has been me t e r e d for a longer pe rio d , the lon g run incom e elast icity betw een 1960 and 1980 (measured against G DP ) has been about 0 .7
(imp lying that each 1% increase in GDP w ill lead to an increase in domest ic demand of 0.7% ). Due to national d ifferences th is figu re , howev er , cannot be app lied with confiden ce to Northern Ireland .
-129- • I S M ME M • • • • • • • • • • • • • • • a l= 6 .3 NON-DOME ST IC WATE R DEMAN D
6 .3.1 Price Elast icity
A ll studie s on industrial water dema nd agree on the existence of' a sma ll ne gative p rice elast icity of demand by non -dom est ic water consumers . Thackray and Archiba ld (198 1) estima ted a price elastic ity of abo ut -0 .3
while Hanke (1979 ) fou nd indications of slightly higher elasticity
center ing around - 0 .4 . Thus a 1% increa se in the water price would reduce indu strial demand by between 0.3% and 0 .4% . How ev er, it is imp ortant to
note tha t the elastic ity is like ly to be lower in No rthern Irelan d since
a large prop or tion of the firms survey ed for these studies belong t o water
intensive secto rs with considerable Sc o p e for water conservation . Such firms are uncommon in Northern Ireland .
Most industrial water users interviewed by Thackray and Archibald , particu larly those for whom water charges are a sub stantial part of their produc tio n costs , indicated that they had already implemented water saving
p rogramm es in respon se to increased water charges or had be en planning to
do so in the future .
Thac kray and Archibald is find ings are suppo rted by the fact that
industrial mete red demand in the Ea st and West M idlands , where the study was carried out , fell by 14% be tween 1973 and 1979 while wate r charges rose by 20% in real terms and ou tput fe ll by only 5% . Simi larly in Ge rmany whe re wate r charges have been increased considerably over the last decade , water consumption by the industrial sec tor has (desp ite substant ial growth in output ) been reduced by 17% be tween 1970 and 198 0 .
6 .3 .2 Output Elast icity
Industria l and comm erc ia l water consump tion can be broken down into a
'domesti c ' component which is directly related t o staff numbe rs and an 'industrial 'compone nt wh ich is a result of the ac tua l p roduction process . wh ile the 'industr ial ' compo nent varies directly w ith the un its of output , the 'dom estic ' component reacts mu ch more slowly t o bu tput changes since firms are gene ra lly reluctant t o take on or shed labour i n respo nse to fluctuations in the demand for the ir goods . Th us , the sho rt run ou tpu t elast icities for different indu st rial sec tors depe nds o n the relative size of the 'domestic ' and 'indust rial ' comp onents of their wa ter deman d .
- 130- Thackray and Arch iba ld reported ou tpu t elast icit ies between 1.0 and
0 .3 for the d iffe rent sec tors w ith a mean of 0 .5. Since their stu dy included m any f irm s from th e min ing and steel ma kin g industries wh ich do not ex ist in Northe rn Ireland and have very low output elast icit ies , the average output elastic ity for Northern Ireland is likely to be sub stantia lly higher . A value in the broad re gion o f 0.7 is su ggested by th is analysis .
-131- RE FERENC ES
Gunderma nn , H .; "Einfluss des Wasserpre ises auf den Verbrauch" '
Gas/Wasser/Waerm e 37 (198 3 ) 2 ; pp 45-50
Hanke , S .H .; "A method of integrating engineering and economic p lannin g" .
Proceedings of the sympo sion on water services financial , en gineering and sc ientific p lann ing , 1977 . Inst itu tion of Water Engineer s an d Sc ient ists ,
London .
Thack ray , J .E . and Archibald , G .G .; "The Severn T rent stu dies of industria l water use "; Proceed ings of th e Institution of C ivil Engineers , Part 1, 198 1, 70 , pp 40 3-432 .
-132- • 1• • • • • • • • 111M1 a a I MB I W II IMII I INI - 1111 111• 6 111. A PPEN D IX 7
UNIT COSTS OF LEAKAGE
7.1 GENERA L
The un it costs of leakage dep end upon two principa l elements .
(a ) The Un it Cap ita l Co st .
This is 'ca lcu lated from the deferment of cap ital expe nditure tha t wou ld be required to increase w ater p roduction . In ma king the assessment of the necessa ry cap ital work s a growth in overa ll demand of 1% p er annum has been used .
Costs of cap ital wo rks are based on current planning . These costs are discounted to the base year (198 1) usin g a rate of 5%. The
discoun ted cap ital cost is converted to a unit cap ital cost by
calculatin g the change in the cap ital cost brought about by a unit
change in supp ly . Th e relevant fo rmula is
(ca ita l co st ) x (0.05 )2 x 100 pence p er cub ic metre 1.05 x (annual increase in su p p l y )
As ind icated above the annual in crease in supp ly is taken as 111 of th e current production .
All costa a re at 1983 levels .
(b ) The Unit Op erating Cost . This comp rise s the current costs pe r cubic meter for electricity , chem icals and op erating p lant , p lus relevant labour costs .
Wh ere several sources supp ly a system the un it qperating costs of the mo st expen sive are used , on the bas is th at th is is the most
economi cal course to fo llow .
- 133- M O • M I • • la a • NI O • • • • OM • • INN 11• 1 • • OM Estima te s of the costs of leakage ha ve been made for each of the principal supp ly systems on the ba sis of the forego ing and are presented below . These do not ma ke allowances for all relevant factors (e .g . trunk main extensions ) but the resu lts are sufficient ly accurate for the p resent purpo se s .
7 .2 EAST ERN DIVIS ION
(a ) Unit Cap ita l Cost
An nua l increase in product ion m3/d 4 000 Cap ita l co st of new works (1) £ 40 x 106
Effect ive co nst ruction date 1986 Discounted Cap ita l Co st £ 3 1.3 x Unit Capita l Cost p/m3 5 .1
(b ) Unit Op era ting Cost (Dunore ) p/m3
(c ) Total Unit Cost of Leakage p/m 3
Note
6 (1 ) Estimated Cost of New Works £ 25 x 10 6 Est imated Fixed Annual Op era ting Costs 4 14 x 10 TOTAL .E4 0 x 106
-134- 0 IM1 10 110 • 11M OIN UM M ONO IMI NOIMM ONO•111 = MI S 7 .3 NORTHERN DIV IS ION
Sy stem Co lera ine/ Ba llymena/ Maghara fe lt/ Ba llymo ney/ Antrim/ Cookstown Moy le La rne
(a ) Un it Cap ital Cost
Annua l increase in
production 1i13/d 370 530 230 6 6 Cap ita l Co st E 1.3 x 10 3.6 x 10 Nil (1) (2 ) (3) Effective cons truction date 1986 1988 Discounted Cap ital Cost £ 1.00 x 106 2.56 x 106 Nil Un it Cap ital Cost p/m 3 1.8 3 .1 NIL
(b ) Unit Op e rating Cost p/m3 3.7 2 .5 4 .7 (Ballinrees ) (Dunore ) (Moyola )
(C) To ta l Unit Co st of Leaka ge p/m 3 5 .5 5.6 4 .7
Note
Exis ting sources shou ld be adequate until the end of the centu ry , if a p ipeline is laid from Ballinrees T reatme nt Works to Glenlou gh Rese rvoir to sup lem ent the Al tnahinch Sou rce in dry years .
A new source w ill be ne eded by 199 0 for which Inver Dam and Treatment
Works are env isaged .
Estima ted Cap ital Cost 4 2,600,000 Estimated Fixed Ope rat ing Co st E. 976 ,000 TOTAL 43 ,576 ,000
Cu rrent sources a re adequate to the end of the ce ntury w ithout sign ificant cap ital expenditure .
- 135- • • • OM M I OM • • • OM1 • OM OM a I MP IS M O OM M O M I OM
I (1) Cam lou gh Source (13 M l/d )
Estima ted Capital cost £ 3,000 ,000 Estimated Fixed Runn ing Co st £ 1,820 ,000 TOT AL £4 ,820 ,000
At the stated growth rate a further new sou rce w ill be needed after
abou t 10 yea rs . Thus a cap ac ity mu lt iplier of 2 .6 is used in d iscoun ting the capital co st (Report No . 26 , Fig. B2 )
-136- (Ca rmoney ) (3) (Ki llyh ev lin/ Ki llyfoyle )
(c) To ta l Unit Co st o f Leakage p/m 3 4 .5 3.9 5 .3
Notes
(1) Cap ital co st of imp rovement to Altnaheglish , which wou ld satisfy only
8 further yea rs increase in dema nd . Thus further wor ks w ill be needed late r and to allow for th is a capa city mu ltip lier of 3 is used
in discounting the cap ital co st .
(2 ) Extensions to Lough Ma cro ry/Stradowan and Lough Bradan are under constru ction and therefore cap ital co sts of these pro jects canno t be deferred . Fo llow ing comp letion of these schem es the resources will be adequate to at least the year 200 1.
(3 ) Propo rtioned between Derg , Braden and Fingrean .
(4 ) Ex tension o f Killyhevlin required in 1992 .
Estimated Cap ita l Cost £ 500 000
Estima ted Fixed Op erating Co st £ 370 ,000 TOT AL £8 70 ,000 -137- APPEND IX 8
COST OF LEAKAGE CONT ROL
8 .1 LEAKAGE CONT ROL ACT IV IT IES
Repo rt No . 26 ou tlines a range of frequ encies for the various leakage contro l activities assoc iated w ith an active waste co ntro l policy . The recomm ended frequ encies are dependent on the un it costs of leaka ge for
individual sup ply areas and on the size of waste meter districts w ithin
those areas .
Th roughou t No rthern Ireland the Unit Co st of Leakage is relatively
h igh and , acco rd ing ly , frequenc ies recommended are generally at the h igh end of the range . However , in ru ra l area s with low population dens ities ,
waste dis tr icts conta in ve ry low numb ers of properties and it is con sidered more app ropriate in these areas that monitoring and inspec tion should be
carried out less freq uent ly .
Recommended frequ encies are summa rised and ex tended in Table A8 .1. Wh ilst the recomm ended frequ encies do not imp ly a fixed frequency for each waste district , they do , how ever , ind icate the level of activ ity required w ith in each supp ly area .
Wh en implementin g an ac tive waste detec tion programm e it is impo rtant that the co rrect balance between monito ring and inspect ion is obta ined .
Wh ilst the co llec tion of reco rds of night flows will not in itself reduce the level o f leakage , it w ill enable resources to be directed to those areas whe re the greatest bene fits , economic and otherw ise , can be obta ined .
8 .2 MA NPOWER REQUIR EMENTS
Productivity figu res obta ined from th e Belfast sub -d iv ision , increased as app rop riate to ma ke a llowan ce for holidays and illness , have been used to estimate the numb er of industria l ma nhours requ ired to carry out each of the va rious leaka ge control activ ities . These estimates have bee n used in Table A .8.2 to calculate the numb er of manhours wh ich shou ld be appo rtioned to waste de tection in each supp ly area in order that the target levels of ne t night flow m ight be obtained .
-138- •
The operat iona l resources nece ssary to ma intain the requ ired level
of ac tivity w ill vary for each supp ly a rea . App roxima tely fifty-seven per
cent of the to ta l envisaged are for step -tes ting and night soun ding . In areas other than the Belfast sub-d ivision th is wou ld invo lve between tw elve
and twenty nights wo rk pe r year in each linesma n 's d istrict and the work cou ld reasonably by ca rried out as ove rt ime . In the Be lfast sub-d ivis ion
it is con side red that shift wo rk will be necessary .
The balance of the waste detec tion p rogramme invo lves work du ring the
day and , consider ing the geo graph ical prob lems invo lved with work ing right
across the ex isting supp ly areas , it is probab le that staff w ill be
organised with in the ex ist ing sub-div ision and linesma n 's dist ricts . It
is likely there fo re that in areas other than the Belfast sub-div ision ,
where waste squ ads as such could operate , was te detection will be abso rbe d as add it ional work w ith in existing structu res . The impact of the add itiona l work on existing duties wou ld have to be assessed and staff ing leve ls re -examined if necessa ry .
In the leakage ana lysis repo rt dated Septemb er 198 3 recomm endat ions
were made rega rd ing app rop riate ope rational resources for the Belfast sub- div ision . An exam ination of existing resources in the other sub-div isions wou ld be neces sary to determi ne how be st the requ ired level of activity can
be ach ieved using ex isting or add itiona l manpower .
8 .3 COST OF LEAKAGE CONT ROL FOR TARGET LEAKAGE LEVE LS
Manpower requ irem ents together with costs relating to transport and superv is ion can be used to calculate cost for each of the leakage control activ ities co nst ituting an active leakage contro l po licy .
These co sts have been est ima ted as fo llow s :-
Step Test ing 125 .00 M .N .F. Reco rd ing F. 12.50 Night Sound ing X, 110.00
Follow Up Investigations S. 120.00
Table A .8 .3 be low extends these costs to estimate the target annua l co st o f leakage contro l for each sup p ly area .
- 139- • II IIII OM MN a a a a IM MN a M O OM
TABL E A .8 .1
RE COMME N DED FRE QUE N C IES FO R LE AKA GE CONT ROL ACT IV IT IES
Propo sed A ve rage Recomm ended F r encies Tota l No . Pe r Year N o . of No . of N o . of (No ./Yea r ) Step M .N .F . N igh t Soundin g/
Prop ertie s Waste P rope rtie s/ Mon it or ing Insp ec tio n T ests Reco rding Fo llow up
Distri ct s D istrict
EA ST ERN DIV IS ION 253409 38 1 6 65 760 228 5 76 0 1 r .4‘ o 1 Co le ra in e/ Ba lleym oney/Mo y le 27548 60 4 59 4 1.5 90 240 90
Ma ghera fe lt/Cookstown 168 58 35 4 82 4 1.5 55 140 55
Bal lymena/An trim /La rne 43227 70 6 18 6 2 14 0 42 0 140
NO RT HE RN DIV IS ION 876 33 165 28 5 800 28 5
SO UT HERN DIV IS ION 79889 173 562 1.5 26 0 69 0 260
Lo ndonde rry /Lima vady 30670 50 6 13 6 2 100 300 100
Straba ne/Oma gh 2 17 15 100 2 17 4 1 100 400 100
Ferm a nagh 17068 60 284 4 1 6 0 24 0 60
W EST ERN DIV IS ION 694 53 2 10 46 2 (4 ) (1.5 ) 26 0 69 0 26 0 M I • • 0 a • a M I a l l MN M I 0 1 OM NM OM M O 1= 11
TABLE A .8 .2
MAN POW ER RE Q UIREM ENTS F OR ACT IVE LEA KAGE CO NT RO L
Propo sed No . Step M .N .F . Night Fo llow Up Tota l Ma n Hou rs
of W aste Test in g Recording Sou nding In vestiga tio ns Per Yea r
D is tr icts
EA ST ERN DIV IS IO N 38 1 No . requ ired pe r ye ar 760 228 5 76 0 76 0 _ Ma n hours pe r a ct iv ity 11.00 1.50 13 .00 13 .50
To ta l man hrs pe r yea r 8 360 34 28 988 0 102 60 3 1 928
NO RTHERN DIV IS ION 165 No . requ ired pe r year 285 800 285 285
Ma n hou rs pe r act iv ity 11.00 1.50 13 .00 13 .50
Tota l man hr s p er yea r 3 135 1200 37 05 38 48 11 888
SO UT HERN D IV IS ION 173 No . requ i red pe r ye ar 260 69 0 26 0 260
Man hou rs p er act iv ity 11.00 1.50 13 .00 13 .5 0
Total man hr s pe r year 2860 1035 338 0 35 10 10 78 5
WE ST ERN D IV IS ION 2 10 No . requi red p er year 260 940 260 260
M an hours pe r ac t iv ity 11.00 1.50 13 .00 13 .50
Total m an h rs pe r year 2860 14 10 3380 35 10 1 1 160 • IN IN I OIN 1•• I NN M I MN • • MO = 11 a 6111 MMI a I NO a a N O •
TA BLE A .8 .3
COST OF LEAKA GE CONT ROL
Propo sed Step -T es ting M .N .F . Reco rding Ni ht Sound in /Fo llow U
No . o f T otal T o tal Investigat io ns
W aste No/ Ave ra ge No / Ave ra ge To ta l T ota l A nnu a l
Distric ts Year Co st Year C ost No/ A vera ge C ost
Year Cost
3 .
1:3
EA ST ERN D IV IS IO N 38 1 76 0 .4 125 2285 4 12.50 76 0 .4 230 E 298 00
SO UT HERN DIV IS IO N 17 3 260 12 5 69 0 .4 12.50 260 E 230 10 1 0 0 0
NO RT H ERN D IV IS ION 16 5 285 E 125 800 12 .50 28 5 230 4 11 1 000
WE ST E RN D IV IS IO N 2 10 26 0 12 5 940 E 12.50 260 2 30 104 0 00 I I N M I 0 1 MN M I • M O IS • OM OM • MN • a M I NM I= M I •
APPEND IX 9
* Costings Eo r treatment works and for la rger schemes fo r Lough Is land Reavy a re marg inal coatings .
N .B . Costs ba sed on previous studies , updated and modified in acco rdance with WEC pu blication T R6 1, Co st Info rmation for Wate r Supp ly Sewage Disposal . A PPEND IX 10
EFFEC TS OF PO SSIB LE SEQUENC ES OF DEV ELO PM ENT FOR EAST ERN AREA SCHEM ES
TA BLE A . 10 .1
1.9% A nnua l Inc rea se in E lectricity Co sts -First Sch eme Op erat iona l in 199 2
Unit Co st of Water - p /m 3
G ROWT H RAT E
- 144- TA BLE A .10 .2
1.9 % Annua l In c rease in E le ctricity Co sts -First Sc hem e Ope rat io na l in 2002
Un it Co st of Wa te r - p /m 3
G ROWT H RAT E Sequence o f Schem es 0 .5% 1.0% 1.5% Size s (M l/ d ) Sites Un it Rank Un it Ra nk Un it Ra nk Co st Co st Cost
Key to Sites C B = C asto r Ray GW = G lenw h irry L (A ), L (B ), L (C ) = Lo u gh Is la nd Reavy
- 14 5- T ABLE A . 10 .3
No in c re ase in e lectricity p r ic es
Unit Co st o f Wate r - p/m 3
G ROWTH RATE Sequence of Sc hem es 0 .5% 1.0% 1.5% S ize s (MI/d ) S it es Un it Rank Un it Rank Un it Ra nk Co st Co st Co st
17-40-65 L (C )-DP-CB 8 .8 3 8 .1 13 7 .7 17
17-40- 110 L (C )-D P-C B 8 .8 3 8 .0 12 7 .4 15
17-6 5-6 5 L (C )-C B -DP 8 .2 1 7 .7 6 7 .3 14
17-6 5- 110 L (C )-C B-G W 8 .2 1 7 .4 3 6 .9 3
17- 110-65 L (C )-C B -DP 9 .1 5 7 .3 1 7 .0 5 .
17- 110- 110 L (C )-C B-G W 9 . 1 5 7 .3 1 6 .7 1
17- 140 L (C )-C B 10 .0 7 7 .5 4 6 .8 2
65- 17-6 5 CB -L (C )-DP 10 .1 a 9 . 1 17 7 .4 16 6 5- 17- 110 CB -L (C )-GW 10 .1 a 7 .6 5 7 .0 6 6 5- 110 C B-G W 10 . 1 a 7 .9 7 7 .2 10
6 5- 140 CB -GW 10 .1 8 8 .2 14 7 .3 13 110- 17-40 CB -L (C )-DP 11.5 12 8 .0 8 7 .2 12
110- 17- 110 CB -L (C )-GW 1 1.5 12 8 .0 a 6 .9 4 110-40 CB -L (B ) 11.5 12 8 .0 a 7 .2 11 110- 110 CB -GW 11.5 12 8 .0 a 7 .1 7
110- 110 GW -C B 12 .5 16 8 .2 15 7 .2 9
- 146- A PPEND IX 11
A BB REV IA T IO NS
The fol low ing abb rev iatio ns are used in th is Repo rt :-
O r ga nizations
DOE/N I De pa rtm ent of the En v ironment fo r Northern Ire la nd NWC National W ater Counc il RW A Re gio na l Wate r Autho r ity W RC W ate r Re search Cent re IH In st itute of Hy dro lo gy , Wa llin gfo rd
G eograp h ica l
GB G rea t Britain NI North e rn Irela nd UK United Ki ngdom
Un its - M et ric
M I M ega l it res (1 m i llio n litre s ) M l/ d Mega l it res pe r day l/ h lit re s pe r hou r l/p /h l it re s p er p rope rty per hou r 1/km /h litre s pe r ki lom etre pe r ho u r 3 m /d cub ic m etres p er day P /m 3 pe nce pe r cub ic metre
Units - Impe ria l m gd mi llio n ga llo ns pe r da y gph ga llons p er hour
T echnica l
A RV An nua l Run o ff V a lu e A DF Ave ra ge Da ily Flow BF I Ba se Flow Index CAP Comm on A gricu ltu ra l Pol icy G DP G ross Dome st ic Produ ct MN F M inimum Night F low NNF Net Night Flow U FW Unacco unted for W ate r SAA R Standa rd An nua l Ave ra ge Ra infal l %p a Pe rcent p er ann um
- 147- á NIIII IO NIO M OIII IM IN O • III II I I M M IS O P OON E NI