Depar t ment of t he Environment for Nort hern Ir STUDY OF WATER DEMAND AND SUPPLY IN NORTHERN IRELAND Volume 2 Ra i Suppor t in g St udies 'ARCH August 1984 on • ide n R1/2 e ms f l- 441% _r 1 fl • SIR ALEXANDER GIBB & PARTNERS in association with DELOITTE, HASKINS & SELLS MANAGEMENT CONSULTANTS I S 10 10 10 0 1 • • • M O M • • • • • • 1 • M a Depar t ment of t he Envir onment f or Nor t her n Ir elan d STUDY OF WATER DEMAND AND SUPPLY IN NORTHERN IRELAND Vol u me 2 Su ppor t i n g St udi es August 1984 on onden y • BELF A T / ,5" SIR ALEXANDER GIBB & PARTNERS in associat ion wit h DELOITTE, HASKINS & SELLS MANAGE MENT CONSULTANTS MNI UMI ONI IINI 10 10 10 1 • 11M M I MI IM IIIM I M DEPA RT M ENT OF THE EN V IRONM ENT FO R NO RT HE RN IRELAND ST UDY OF WAT ER 6EMAND AND SU PPLY IN NORT HERN IRE LA ND V OLUM E 2 SUPPO RT ING ST UD IE S TA BLE OF CO NTENT S PA GE NO . INT RO DUCT ION AND S UMMA RY (i ) C HA PT ER 1 SOURC E YIE LDS 1 1.1 In tro du ct ion 1 1.2 River F low Reco rd s 1 1.3 M eteo ro lo gica l Data 10 1.4 Reco rd Extension 14 1.5 Re g iona l Sto ra ge Y ield Relat io nship 2 1 1.6 Yie ld E st im atio n 27 1.7 R iv er Ab stract ions 35 1.8 Severity o f Period (1970- 198 3 ) 37 1.9 Lo ugh Neagh 4 0 1. 10 G roundwa ter 4 1 1. 11 Co nc lu sio ns and Re comm e ndatio ns 42 C HA PT ER 2 HOUSEHO LD SURVE Y 45 2 .1 F ind ings of the Su rvey 45 2 .2 Ho u seho ld Su rvey Qu estionnaire 45 C HA PT ER 3 DETA ILS OF M ET ERED D IST R ICTS 6 1 PAG E NO . C HA PTER 4 A DJU ST M ENT OF M ET ERE D CO NS UMPT ION TO ACCO UN T FO R NON -M ET ERED CONSUMERS 6 3 4 .1 Ag ricu ltu re 63 4 .2 Indu stry 65 4 .3 Co nstru c t ion 65 4 .4 Comm e rce and oth er Se rvic es 65 C HA PT ER 5 LEA KAG E IN SUPPLY SYST EMS 70 5 .1 Ob je ctive 70 5 .2 Ba se Year 70 5 .3 Method 70 5 .4 Night F low Ra tes 7 1 5 .4 . 1 Ge nera l 7 1 5 .4 .2 Ea stern Div ision 74 5 .4 .3 No rthern Div isio n 74 5 .4 .4 Sou th ern Div is ion 74 5 .4 .5 Weste rn D iv isio n 75 5 .5. Estim at ion o f Le aka ge 76 5 .5 .1 Dist rib utio n Sy stem 76 5 .5 .2 Tr unk Ma in Leaka ge 76 5 .5 .3 To ta l Leakage 79 L IST OF TABLES PAG E NO . TAB LE 1.1 Summ ary of F low Data from No rthe rn Ire land 3 T AB LE 1.2 Ava ilab le Re co rd s fo r An na long Ca tc hm ent T AB LE 1.3 Red , Blu e , G reen and Contro l Monthly Ave rage Ca tchment Ra in fa ll 7 TA BLE 1.4 .Re d , B lue , G re en a nd Contro l Month ly Ave ra ge C atchme nt Run off 8 TA BLE 1.5 . Summ ary o f .F low Da ta from Re pub l ic o f Ire land 9 T ABL E 1.6 Summa ry o f Flow Da ta fr om South We st Sco tland 9 TAB LE 1.7 Annua l Catchm ent Ra in fa ll fo r No r the rn Ireland Ca tchm ents 11 TAB LE 1.8 Ra in fal l Ratio s for Sile nt V a lley and Anna long Ra ingau ge s 12 TAB LE 1.9 SAA R (194 1-70 ) fo r Silent Va lley a nd Anna long Catchm ent 12 TA BLE 1. 10 De fin it ion o f Va riab le s used for Record Ex tension 16 TA BL E 1. 11 Corre la tio n Mat rix fo r An na long Record Ex te ns ion 17 TAB LE 1. 12 Correlation Ma trix for Woodbu rn Record Extension 17 T A BLE 1. 13 Sto ra ge Requ ire ment fo r 50 y ear Re turn Pe rio d 24 T AB LE 1. 14 Y ie lds of Re servo irs in No rthe rn Irela nd 28 T A BLE 1. 15 Yie ld of Rd ver Derg at T iev enn y • 38 TAB LE 1.16 Data an d Ra nk o f Highest De fic it in Pe rio d 1970- 1983 38 TAB LE 1. 17 Re turn Pe riod o f Ar magh Rainfa ll fo r Se le cted Du rations • 39 T ABLE 2. 1 Own ersh ip of Wate r Us in g App li ance s 46 T AB LE 2 .2 Hou seho ld Cha ra cter is tics by T ensu re Stat us 47 TA BLE 4 .1 Co n centratio n of Ag ricu ltu ra l Water U sage 64 • TAB LE 4 .2 Con ce nt ra tion o f Indu st rial W ate r Usa ge 66 TAB LE 4 .3 Co ncentra t ion of Co n stru ct ion W ate r U sage 67 TAB LE 4.4 Con cent ra tion of Serv ice Wate r Usage 68 TAB LE 5 .1 Me te red M inim um N ight Flow s in Se le cted A re a s 72 t ABLE 5 .2 M ete re d Le g it im ate Night F lows in Se lected A reas 7 3 TABLE 5 .3 Night F l o W Rates and Leakage 77 L IST OF F IGURE S Fo llow in g Page No F IG U RE 1. 1 Lo ca t io ns o f Gaugin g Stations us ed in Stu dy 1 F IG URE 1.2 Sile nt Va lley Sy stem 3 F IGU RE 1.3 Woo dbu rn Comp lex 5 F IG URE 1.4 Re la t ionsh ip Be tw ee n Potent ia l and A ctua l Ev ap o ratio n 13 F IGU RE 1.5 Sto ra ge/Yield Diagra m s for An na lo n g Ca tchment 189 5- 19 79 2 1 F IG URE 1.6 Rela t io nship be tw een 10 ye ar Retu rn Pe rio d Sto ra ge and 80 Pe rcentile Ex ce ed an ce D is charge fo r Rep ub lic of Ire land Ca tchm ents 22 F IGU RE 1.7 Sensit iv ity o f Sto ra ge/Yie ld to Pe riod o f Reco rd - A nna lo n g 23 F IGU RE 1.8 50 Yea r Re tu rn Pe rio d Storage/Y ie ld Relat ionship s 24 FIG URE 1.9 Re giona l De sign Cu rves fo r No rthe rn Ire la nd 25 F IGU RE 1. 10 Comp a r ison of Re giona l Sto rag e/ Yie ld Relationship s 25 FIG URE 1. 11 Yield/ Fa ilu re Re la t ions hip fo r Sile nt Va l ley 32 F IGU RE 1.12 Retu rn Pe riod o f Rationing fo r G ive n Yie ld s and Proba bi lity of To ta l Fa ilu re 34 INT RO DUCT ION AN D SUMMA RY Th is vo lume of the repo rt on the Study o f the W ater Dema nd and Sup p ly in No rthe rn Ire land comp rise s chap te rs w hich d escribe the wor k ca rried out on a numb er o f fundam enta l to p ic s w hich supp o rt the ma in study . These a re sum ma rised as fo llow s :- 1. SOU RCE Y IELDS Th is ch ap ter compr is es a re v iew of th e data tha t is av a i lab le on w ate r re so u rc es , p art icu la rly su rface w ater sou rces , w hich a re p redom inant in th e Pro vince . A regiona l sto rage/yie ld re la tionsh ip is de ve lope d and u se d for the asse ssm ent of the re l iab le y ie lds of a ll reservo ire d ca tchments in No rth ern Ire la nd at retu rn pe rio d s of 1 in 20 and 1 in 50 y ears .