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?

Pa sha sto rm Syg na sto rm (1974)

• 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
• 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. No b b ys 2007 a nd histo ric a l 1998

HOW EXTREME WAS THE RAINFALL?

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. No b b ys 2007 a nd histo ric a l

IT WAS (VERY) WET MONTH

Pa sha sto rm

• June 2007
• 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

• 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 No b b ys 2007 a nd histo ric a l

IMPACTS HIGHLIGHTS

POWER OUTAGE

• 1 in 3 ho use s witho ut po we r.
• L
• 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.

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

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
• 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
• 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
• 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

• f Hunte r St We st pre c inc t. Curre ntly no t.

Co nta ine r 1 Co nta ine r 2 Ne w supe rma rke t de ve lo pme nt So lid wa ll o f b uilding s

• n Sth Hunte r St
• E

vide nc e o f fa st (Yo uT ub e , windo ws b lo wn

• ut), de e p

(1.5m)wa te r a t c nr Hunte r a nd Na tio na l Pk St

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

• 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).

YOUTUBE MAKES ALL THE DIFFERENCE (7,290,096 DOWNLOADS)

Que stions?