THE PASHA STORM 4 YEARS ON: WHAT DID WE LEARN? PASHA REPORT Autho - PowerPoint PPT Presentation

THE PASHA STORM 4 YEARS ON: WHAT DID WE LEARN?

PASHA REPORT • Autho rs • Da nie lle Ve rdo n-K id d • Philip Ha ine s • Antho ny K ie m • Ga rry Willg o o se • Pull to g e the r a ll studie s b y inte re ste d pa rtie s. No ne w wo rk o the r tha n inte g ra tio n. • www.nc c a rf.e du.a u

SOME STORM CONTEXT

HOW EXTREME WAS THE WIND? No b b ys 2007 a nd histo ric a l Syg na sto rm (1974) Pa sha sto rm 1998 I n 1960-da te • the Pa sha sto rm wa s no t pa rtic ula rly e xtre me . Co mb ina tio n • o f ra infa ll a nd wind c ritic a l. No fre q ue nc y • a na lysis b ut pro b a b ly a b o ut 1 in 10 ye a rs o r le ss.

HOW EXTREME WAS THE RAINFALL? No b b ys 2007 a nd histo ric a l Pa sha sto rm Syg na sto rm (1974) 1998 Sig nific a ntly • mo re ra in pre c e ding the Pa sha sto rm. Pe a k • inte nsitie s g re a te r tha n 1 in 100 ye a rs.

IT WAS (VERY) WET MONTH No b b ys 2007 a nd histo ric a l Pa sha sto rm June 2007 • o ne o f the we tte st mo nths o n re c o rd (1890- da te ) So Pa sha • sto rm a c o mb ina tio n o f b o th e xtre me wind a nd e xtre me ra infa ll. Ab o ut 1 in 20 • ye a r

IMPACTS HIGHLIGHTS

POWER OUTAGE • 1 in 3 ho use s witho ut po we r. • L o ts o f kno c k o n e ffe c ts (e .g . Hunte r Wa te r) • L a rg e st po we r re c o ve ry o pe ra tio n in E a ste rn Austra lia ’ s histo ry. 93,000 c a lls o ve r we e ke nd. • Ma ny a s a re sult o f tre e thro w. Ro o ts pulle d o ut o f so il b e c a use o f we t so il. • Also pro b le ms with po we r po le s fa lling o ve r.

FLOODING • A ta le o f two flo o ds • F la sh flo o ding in the c ity o n F rida y nig ht, multiple flo o d pe a ks, ra pid rise a nd fa ll (< 1 ho ur). Mo re 1 in 100 ye a r, muc h flo o ding trig g e re d b y sto rm syste m b lo c ka g e s. • Hunte r F lo o ding … the c la ssic Hunte r flo o d in Ma itla nd. 1 in 40 ye a r. Re la tive ly mino r impa c ts.

URBAN FLASH FLOODING • Ra pid, little wa rning , e sc a pe ro ute s c ut o ff. • SE S ha d 20,000 c a lls, 3000 o n F rida y nig ht in 2 ho urs. Ove rwhe lme d. • 10,000 ho use s flo o de d. • Wind a pa rtia l fa c to r in de b ris g e ne ra tio n. • De b ris c a use d b lo c ka g e s. Co nta ine rs fro m a pa rtme nt c o nstruc tio n. Ca rs fro m c a r ya rds. • Blo c ka g e fa ilure s c a use d wa te r surg e s.

Co lo urb o nd fe nc ing pa ne ls Cyc lo ne me sh fe nc ing

SES • 20,000 c a lls; 5000 flo o ding . 1000-2000 o ve r flo o r flo o ding . • SE S de pe nde nt o n the o ld Ada msto wn a rmy b a se fo r hig h c le a ra nc e ve hic le s … a ll mo ve d to Sing le to n a fte r the the re de ve lo pme nt. SE S use d the ir o wn 4 whe e l drive s. • Muc h lo c a l flo o ding ma de wo rse b y b o w wa ve s o f 4 whe e l drive s. • L o c a lise d flo o ding due to b lo c ka g e s

AN EXAMPLE OF BETTER PRACTICE: HUNTER WATER

MODIFICATION OF INFRASTRUCTURE (DETAILS COUNT) • Ac c e le ra te d re pla c e me nt o f dry we ll pumps. • Se a ling o f a c c e ss ro a ds to pump sta tio ns. • Wiring suita b le fo r g e ne ra to r e me rg e nc y plug in.

NOTHING SEEMS TO HAVE CHANGED

COTTAGE CREEK • Blo c ka g e b y c o nta ine r re sulte d in flo o d le ve ls b e ing 1 m hig he r tha n o the rwise in Ne wc a stle We st. • Pro b le m is a wa ll b uilding s a lo ng Hunte r St b lo c ks o ve rflo ws fro m sto rmwa te r c ha nne l. • T his sho uld b e a n c o nside ra tio n in future re de ve lo pme nt o f Hunte r St We st pre c inc t. Curre ntly no t.

Co nta ine r 1 Co nta ine r 2 So lid wa ll o f b uilding s o n Sth Hunte r St E vide nc e o f fa st • (Yo uT ub e , windo ws b lo wn o ut), de e p (1.5m)wa te r a t c nr Hunte r a nd Na tio na l Pk St Ne w supe rma rke t de ve lo pme nt

STORMWATER CHANNELS • Sig nific a nt infra struc ture just a b o ve 1 in 100 ye a r flo o d le ve ls whic h c a n c a tc h flo a ting de b is. De b ris no t no rma lly c o nside re d in de sig n o f urb a n syste ms. • Sma ll o pe ning s (le ss tha n fe nc e pa ne l size ) o n ma ny b ridg e s a nd c ulve rts. • No t c le a r who wa s o ve ra ll re spo nsib ility. NCC, Hunte r Wa te r, No W, Ca tc hme nt Ma na g e me nt T rust.

ONE OVERREACTION?

LAMAN ST FIGS • A risk a sse ssme nt o f de a ths due to fig tre e fa ilure trig g e re d b y pa rtia l ro o t fa ilure o f 2 fig s during the Pa sha sto rm.

RISK • T re e lo g ic re po rt risk o f ha rm 1 in 19.8 pe r tre e pe r ye a r. • Risk o f ha rm 52%/ ye a r in L a ma n St • One de a th o r se rio us ha rm e ve ry 2 ye a rs. L a ma n Stre e t F ig T re e 1 in 19.8 T re e s in a re a s o f hig h pub lic use (UK) 1 in 10,000,000

PASHA AND THE FIGS • One o f the fig s suffe re d struc tura l da ma g e (c ra c king ) whic h is func tio n pure ly o f wind spe e d. • Se c o nd fig sta rte d to pull its ro o ts o ut (tre e thro w) whic h is func tio n o f wind a nd so il stre ng th (a nd so il mo isture ). • Wind a nd ra in c o mb ina tio n a b o ut 20 time s le ss like ly tha n wind a lo ne , tho ug h a na lysis o f implic a tio ns fo r tre e s ha s no t b e e n do ne . • E mpiric a l e vide nc e : E ne rg y Austra lia ha d wo rst po we r o uta g e in e a st c o a st histo ry prima rily a s a re sult o f e xc e ssive tre e thro w (due to we t so il).

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