Wa ste wa te r Ne two rk Ove rflo w Co nse nt CONSUL T AT ION ME E T ING 3 AUGUST 2016 BRIDGE T O’ BRIE N AND MIK E BOURK E , CHRIST CHURCH CIT Y COUNCIL
Ove rvie w Wha t is waste wa te r? u Curre nt sta te o f the wa ste wa te r ne two rk u Why do wa ste wa te r o ve rflo ws o c c ur? u Wa ste wa te r o ve rflo w c o nse nt p ro c e ss u Ho w fre q ue ntly do o ve rflo ws o c c ur? u Wha t is the c urre nt sta te o f the wa te rways? u Wha t is Co unc il do ing to impro ve the wa te rwa ys? u Wha t is the Co unc il do ing to re duc e o ve rflo ws? u Wha t c a n yo u do to impro ve the wa te rwa ys? u Wha t do yo u va lue a b o ut the wa te rwa ys whe re o ve rflo ws o c c ur? u
Wha t is wa ste wa te r? Waste wate r is wate r fro m inte rnal drains (e .g . to ile t, sho we r, ba th, u kitc he n sink, dishwa she r, wa shing ma c hine , la undry tub) Wa ste wa te r is c o nve ye d b y pipe s a nd pump sta tio ns to wa ste wa te r u tre a tme nt plants fo r tre atme nt and dispo sal T he ma in purpo se o f a wa ste wa te r syste m is to pro te c t pub lic he a lth u In o rde r o f prio rity, a im to ke e p wa ste wa te r: u Off pro pe rtie s u Off the stre e t u Out o f wa te rwa ys u Sto rmwa te r c o me s fro m ra infa ll a nd is c o lle c te d in e xte rna l dra ins u (e .g . do wnpipe s o ff ro o fs, ke rb a nd c ha nne l o n ro a ds)
Why do we t we a the r o ve rflo ws o c c ur? Sto rmwate r and g ro undwa te r g e ts into the waste wate r ne two rk u thro ug h c ra c ke d pipe s, flo o de d ma nho le s a nd g ully tra ps, a nd c ro ss-c o nne c tio ns (e .g . do wnp ipe a c c ide nta lly c o nne c te d to wa ste wa te r) T his c a n c a use the c a p a c ity o f the wa ste wa te r ne two rk to b e u o ve rwhe lme d in a la rg e sto rm Co nstruc te d o ve rflo w po ints a re sa fe ty va lve s in the wa ste wa te r u ne two rk, to pre ve nt o ve rflo ws o n pro pe rtie s a nd o n the stre e t F o r 3 ye a r Annua l Re c urre nc e Inte rva l sto rm: u 125 ma nho le s o ve rflo w, to tal o ve rflo w vo lume 42,000 m³ u 22 c o nstruc te d o ve rflo ws o pe ra te , to ta l o ve rflo w vo lume 36,000 m³ u
Ho w do e s Christc hurc h c o mpa re to o the r c itie s?
Curre nt sta te o f the wa ste wa te r ne two rk SCIRT wa ste wa te r re pa ir wo rk is la rg e ly c o mple te d b ut ha s o nly u re pa ire d da ma g e to c ritic a l a sse ts o r a sse ts in c ritic a l lo c a tio ns, o r da ma g e tha t is e xpe c te d to la st le ss tha n 5 ye a rs Re pla c e me nt o r re pa ir ma jo r da ma g e a c ro ss ha lf o f the ne two rk u u Whe re o b vio us infiltra tio n fo und this will b e re pa ire d b y SCIRT Po st SCI RT ne two rk mo de l ha s b e e n b uilt u u Ne e ds c a lib ra ting in we t we a the r to impro ve mo de l a c c ura c y Curre ntly a ve ra g e flo ws a re b a c k to “no rma l” - ma yb e ! Ho we ve r u the lo ng dry pe rio d ma y b e misle a ding a nd g ro undwa te r le ve ls a re lo w.
Christc hurc h Wa ste wa te r T re a tme nt Pla nt T o ta l Da ily F lo w 300,000 280,000 low 260,000 a g e F 240,000 olling 91 Da y Ave r (m³/ da y) 220,000 200,000 180,000 160,000 140,000 R 120,000 100,000 1-Jun 1-Jul 1-Aug 1-Se p 1-Oc t 1-No v 1-De c 1-Ja n 1-F e b 1-Ma r 1-Apr 1-Ma y 2010/ 11 2011/ 12 2012/ 13 2013/ 14 2014/ 15 2015/ 16
Wa ste wa te r o ve rflo w c o nse nt pro c e ss Curre nt we t we a the r o ve rflo w c o nse nt e xpire s in 2025 u Due to e a rthqua ke da ma g e to wa ste wa te r ne two rk, no n- u e nfo rc e me nt a g re e me nt with E nviro nme nt Ca nte rb ury By 1 Ma rc h 2017, ne e d to c o mply with e xisting c o nse nt o r a p ply fo r u a ne w c o nse nt Curre ntly running 15 ye a rs histo ric a l ra infa ll in wa ste wa te r ne two rk u mo de l to a sse ss c o mplia nc e , b ut will ta ke se ve ra l mo nths Due to e a rthq ua ke da ma g e pro b a b ly wo n’ t c o mply with e xisting u c o nse nt, so ne w c o nse nt applic a tio n unde rwa y Ne w c o nse nt will inc lude L ytte lto n Ha rb o ur a nd Aka ro a Ha rb o ur u
Wa ste wa te r o ve rflo w c o nse nt pro c e ss Pre vio us c o nse nt b a se d o n re duc ing the fre q ue nc y o f o ve rflo ws to u the Avo n Rive r, He a thc o te Rive r a nd Avo n/ He a thc o te E stua ry But no re a l link b e twe e n o ve rflo w fre q ue nc y a nd e ffe c ts o n the u e nviro nme nt T a king a n e ffe c ts b a se d a ppro a c h fo r the ne w c o nse nt: u Wha t va lue s do the wa te rwa ys ha ve ? u Wha t e ffe c ts do wa ste wa te r o ve rflo ws ha ve o n tho se va lue s? u Wha t is the b e st pra c tic a b le o ptio n to re duc e tho se e ffe c ts? u
We t We athe r Ove r flows - Avon He athc ote 60 Numb e r o f Ove rflo ws Pe r Ye a r 50 40 30 20 10 0 2003/ 04 2005/ 06 2007/ 08 2009/ 10 2011/ 12 2013/ 14 2015/ 16 No pe r ye a r No o f L o c atio ns in to tal Max no o f lo c atio ns pe r e ve nt
Wha t is the Co unc il do ing to re duc e o ve rflo ws? Rub b e r fla ps o n c o nstruc te d o ve rflo ws, to sto p rive r wa te r g e tting into u wa ste wa te r ne two rk I n flo o d pro ne a re a s, re pla c ing ve nts o n o ur ma nho le s with so lid lids, to u sto p sto rmwa te r ge tting into wa ste wa te r ne two rk In flo o d pro ne a re a s, putting pla stic lids o n ho use ho ld g ully tra ps, to u sto p sto rmwa te r ge tting into wa ste wa te r ne two rk Co nduc te d ho use to ho use surve ys in Dia mo nd Ha rb o ur a nd L ytte lto n, u to ide ntify whe re sto rmwa te r is ge tting into o ur wa ste wa te r syste m a nd a sking pro pe rty o wne rs to fix issue s Ho use to ho use surve ys pla nne d ne xt in Aka ro a a nd the n Go ve rno rs u Ba y Co mple te d Ma jo r Se we r Upg ra de pro je c t, $150 millio n o f ma jo r pro je c ts u o ve r 15 ye a rs
Wha t is the Co unc il do ing to re duc e o ve rflo ws? In flo o d pro ne a re a s, re pla c ing ve nts o n o ur ma nho le s with so lid lids, u to sto p sto rmwate r g e tting into waste wa te r ne two rk In flo o d p ro ne a re a s, putting pla stic lids o n ho use ho ld g ully tra ps, to u sto p sto rmwate r g e tting into waste wa te r ne two rk
Wha t is Co unc il do ing no w to re duc e o ve rflo ws? Re duc ing infiltra tio n u Suppo rting the SCIRT re pa ir pro gra m u u Re ne wing se rio usly da ma g e d pipe s u Re pa ir ma jo r b re a ks a nd le a ks id e ntifie d thr o ug h CCT V u Pr e ssur e se we r a nd va c uum a re a s will ha ve muc h le ss infiltra tio n.
Wha t is Co unc il pla nning to do to re duc e o ve rflo ws? Alre a d y spe nt so me $50 millio n o n ne w Pump Sta tio n 11, pre ssure u ma ins, F e nda lto n Pump Sta tio n a nd duplic a tio n, a nd We ste rn Inte rc e pto r fo r a dditio na l c a pa c ity. Ric c a rto n Ro a d wa ste wa te r trunk ma in upg ra de a nd L o we r u Ric c a rto n Inte rc e p to r, $13.7 millio n o ve r F Y16-18 Co lo mb o Stre e t wa ste wa te r trunk ma in upg ra de a nd Be c ke nha m u Stre e t c ro ss c o nne c tio n $2.4 millio n o ve r F Y16-18 He a thc o te Rive r we t we a the r wa ste wa te r o ve rflo w re d uc tio n u pro je c t, $19.3 millio n o ve r F Y19-25 No rthe rn Re lie f pro je c t, $46.7 millio n o ve r F Y19-25 u T ota l of $82 million in L ong T e rm Pla n for re duc ing ove rflows u
Wha t is the c urre nt sta te o f the wa te rwa ys? Co unc il c a rrie s o ut e xte nsive mo nito ring o f wa te r q ua lity – o ve r 7,000 u sa mple s la st ye a r K e y c o nta mina nts: u 1. Se dime nt – smo the rs ha b ita t a nd fo o d, c a n b e c o nta mina te d. Co me s u fro m runo ff fro m c o nstruc tio n site s, unsta b ilise d surfa c e s, ve hic le s a nd e a rthq ua ke s 2. Me ta ls (zinc a nd c o ppe r) – to xic to fish a nd o the r c re a ture s. Co me s fro m u b ra ke pa ds, tyre s a nd b uilding pro duc ts (ro o fs, spo uting , do wnpipe s) 3. Ba c te ria – pub lic he a lth risk. Mo stly c o me s fro m do g s a nd duc ks, a nd u o c c a sio na lly fro m wa ste wa te r o ve rflo ws 4. Nutrie nts (nitro g e n a nd pho spho rus) – c a n b e to xic (e .g . a mmo nia ) and u e nc o ura g e g ro wth o f we e ds a nd a lg a e . Co me s fro m fe rtilise r, so ils, fa e c e s o f live sto c k, duc ks a nd do g s. Mo st site s no c ha ng e sinc e 2007, a nd with re mo va l o f la rg e a mo unts o f u se dime nt, the wa te rwa ys a re b a c k to no rma l a fte r the e a rthq ua ke s
Wha t is Co unc il d o ing to impro ve wa te rwa ys? Co mmitte d to impro ving the q ua lity o f o ur wate rwa ys, re fle c te d in u o ne o f o ur he a lthy e nviro nme nt c o mmunity o utc o me s: u Wate r quality and quantity is pro te c te d. Pla n to spe nd o ve r $212 millio n o n p ro je c ts in the ne xt 10 ye a rs to u impro ve wa te r q ua lity
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