Atla s 14 nviro nme nta l Co mmissio n RST July 18, 2018 UNDE E - PDF document

OOD RISK L IN’S F ANDING AUST Atla s 14 nviro nme nta l Co mmissio n RST July 18, 2018 UNDE E

Ove rvie w 2  Ra infa ll Da ta Cha ng e s  So lutio n Optio ns  Re c o mme nde d Co de Ame ndme nts  I mpa c ts to Re side nts  Ne xt Ste ps

NOAA Atla s 14 - Ba c kg round 3  Na tio nwide study o f ra infa ll inte nsitie s  Pa rtne rs:  F e de ra l: Na tio na l We a the r Se rvic e , U. S. Army Co rps o f E ng ine e rs, F e de ra l Hig hwa y Administra tio n  Sta te / L oc a l: T xDOT , Ha rris Co unty F lo o d Co ntro l Distric t, City o f Austin, e t a l.

Ra infa ll De pth Cha ng e s (Pre limina ry) 4 Re c urre nc e Curre nt Ra infa ll Atla s 14 Ra infa ll in Inte rva l De pth in inc he s inc he s 25- ye a r 7.6 Almost 10 100- ye a r 10.2 Up to 13+ 500- ye a r 13.5 Not ye t a va ila ble

City- wide Atla s 14 Impa c ts 5  Appro xima te numbe r of building s in floodpla in (e xc luding Co lo ra do Rive r flo o dpla in) Curre nt Curre nt Are a Diffe re nc e % Inc re a se 100- Ye a r 500- Ye a r City L imits 3,702 6,533 2,831 76%  Appro xima te pe rc e nt of a re a in the floodpla in (e xc luding Co lo ra do Rive r flo o dpla in) Curre nt Curre nt Are a % L a rg e r 100- Ye a r 500- Ye a r City L imits 7% 9% 26%

Re g ula tion Re vision Options 6  Do No thing  Disre g a rd Atla s 14 a nd ma inta in c urre nt re g s  Do e sn’ t pro te c t re side nts fro m flo o d ha za rds b a se d o n ne w unde rsta nding o f flo o d risks

Re g ula tion Re vision Options 7  Wa it to c ha ng e re g s until flo o dpla in studie s a re upda te d  Upda ting flo o dpla in studie s will ta ke a minimum o f two ye a rs  L ife / sa fe ty implic a tio ns a re to o sig nific a nt to de la y  WPD will initia te flo o dpla in study upda te s imme dia te ly

Ac t Now to Re vise Re g ula tions 8  Upda te re g s using c urre ntly a va ila b le da ta  Pro vide s imme dia te pro te c tio n a nd vita l info rma tio n to re side nts  Use s re a dily a va ila b le , va lid da ta

Propose d Code Ame ndme nt 9  Re vise flo o dpla in de finitio ns  Re de ve lo pme nt e xc e ptio n  Co lo ra do Rive r e xc e ptio n  Cha ng e minimum fre e b o a rd to 2 fe e t

Propose d Code Ame ndme nt 10 Re c urre nc e Curre nt Ra infa ll Atla s 14 Inte rva l De pth in inc he s 25- ye a r 7.6 Almost 10 inc he s 100- ye a r 10.2 Up to 13+ inc he s 500- ye a r 13.5 Not ye t a va ila ble

Re vise floodpla in de finitions 11 Onion Cre e k L ittle Wa lnut Cre e k  100- ye a r = Atla s 14 100-ye a r o r F E MA 500-ye a r  25- ye a r = Atla s 14 25-ye a r o r fully de ve lo pe d 100-ye a r

Re vise floodpla in de finitions 12  E nc ro a c hme nt  Must sa tisfy flo o dpla in rule s  Sa fe a c c e ss  Ac c e ss pa th min. 1-ft a b o ve  F re e b o a rd  Min. 2-ft a b o ve

Colora do Rive r F loodpla in 13  Ma inta in c urre nt 100-ye a r flo o dpla in a lo ng Co lo ra do Rive r

Re vise floodpla in de finitions – Why? 14  I nfo rm pub lic o f c urre nt unde rsta nding o f flo o d risk  Curre nt, va lid 500-ye a r is a ppro xima te ne w 100-ye a r

Re vise floodpla in de finitions – Why? 15 Colora do Rive r wa te rshe d  Atla s 14 c ha ng e s no t e xpe c te d to sig nific a ntly a ffe c t Co lo ra do Rive r wa te rshe d upstre a m o f Austin

Re de ve lopme nt e xc e ption 16  A re side ntia l b uilding in the 25- o r 100-ye a r flo o dpla in c a n b e re de ve lo pe d a s lo ng a s:  Ab o ve 100-ye a r flo o dpla in b y 2 fe e t  A ma ximum g ro ss flo o r a re a tha t is the la rg e r o f e xisting o r 2,200 sq ua re fe e t  Do e s no t inc re a se numb e r o f dwe lling units

Re de ve lopme nt e xc e ption 17 Unde r c urre nt rule s: 100- ye a r floodpla in Pro pe rtie s in g re e n like ly to re de ve lo p unde r the pre -1983 e xc e ptio n Pro pe rtie s in ye llo w like ly to re de ve lo p with a n a dministra tive va ria nc e Pro pe rtie s in re d re q uire a Co unc il va ria nc e to re de ve lo p 25- ye a r floodpla in

Re de ve lopme nt e xc e ption 18 Unde r ne w rule s: 100- ye a r floodpla in All pro pe rtie s ha ve sa me o ppo rtunity to re de ve lo p with a size limita tio n a nd e le va te d finishe d flo o r unde r a n e xc e ptio n F lo o d risk will b e re duc e d in a ll c a se s 25- ye a r floodpla in

Re de ve lopme nt e xc e ption – Why? 19  I nc e ntivize s re de ve lo pme nt while re duc ing flo o d risk  Ove r time re duc e s the numb e r o f b uilding s a t risk o f flo o ding  Simplify c o de  2,200 sq . ft. is me dia n sing le -fa mily ho me size in Austin

Colora do Rive r e xc e ption 20  E xpa nd 100-ye a r e nc ro a c hme nt e xc e ptio n to inc lude L a ke Austin a nd L a ke T ra vis

Colora do Rive r e xc e ption – Why? 21  Co lo ra do Rive r flo o ding is no t e xpe c te d to ha ppe n in a “fla sh”  Still re q uire s no a dve rse impa c t a nd fre e b o a rd – wa ive s sa fe a c c e ss

Minimum fre e boa rd to 2 fe e t 22  Minimum he ig ht b e twe e n b uilding ’ s lo we st flo o r a nd 100- ye a r flo o dpla in  Mo re tha n 140 T e xa s c o mmunitie s ha ve fre e b o a rd o f 2 fe e t o r hig he r

Minimum fre e boa rd to 2 fe e t – Why? 23  F re e b o a rd is the sing le -mo st e ffe c tive me a ns fo r re duc ing flo o d risk to a b uilding in the flo o dpla in  Simplify c o de – c urre nt fre e b o a rd re q uire me nt fo r a dministra tive flo o dpla in va ria nc e s a nd Ce ntra l Busine ss Are a e xc e ptio n is 2 fe e t, e lse whe re it’ s 1 fo o t  Re duc e d flo o d insura nc e c o sts c a n o ffse t inc re a se d c o nstruc tio n c o st

Atla s 14 Impa c t to home owne rs 24  Ne w unde rsta nding o f flo o d risk  Pro pe rty va lue s  F lo o d insura nc e c ha ng e s a t le a st 3 ye a rs a wa y  Ra te s ma y g o up  I nsura nc e re q uire me nts ma y c ha ng e  T a lk to a n insura nc e a g e nt no w  Se e impa c ts a t AT Xflo o dpro .c o m

Code Ame ndme nt Proc e ss a nd 25 T ime line July June July July July I nte rna l a nd C&O DI F M Co mmitte e E nviro nme nta l Pla nning E xte rna l Co mmitte e (E nviro nme nta l Co mmissio n Co mmissio n Sta ke ho lde r (PC & ZAP) Co mmissio n) Pub lic He a ring Me e ting s I nte rna l a nd Pla nning C&O City Co unc il E xte rna l Co mmissio n Ordina nc e Co mmitte e Pub lic Sta ke ho lde r Pub lic Ado ptio n (PC & ZAP) He a ring Me e ting s He a ring Oc to b e r Aug ust Aug ust Aug ust 3 pub lic he a ring s Pub lic E duc a tio n & At le a st 4 sta ke ho lde r me e ting s Outre a c h

Ne xt Ste ps 26  Pub lic He a ring s & Sta ke ho lde r Me e ting s  Che c k AustinT e xa s.g ov/ a tla s14 fo r de ta ils  Pub lic E duc a tio n & Outre a c h  Po st c a rds to pro pe rtie s in 100/ 500-ye a r flo o dpla ins  Ge o g ra phic a lly b a se d pub lic me e ting s  WPD sta ff to de te rmine a pplic a tio n o f ra infa ll va lue s fo r Austin a re a (Oc t-De c 2018)  Rule s c ha ng e pro c e ss – DCM (Q2 o r Q3 o f F Y 2019)  Re -ma pping o f Austin flo o dpla ins (2019 – 2021)

27 F ollow our prog re ss a t: AustinT e xa s.g o v/ a tla s14 Conta c t us a t: Atla s14@ AustinT e xa s.g o v F lo o dpla in Ho tline 512-974-2843 Vie w floodpla ins a t: AT Xflo o dpro .c o m

History of Ra infa ll Inte nsity Studie s for 28 Austin Ra infa ll fro m 100-ye a r 24 hr sto rm 14 Austin DCM, 1977 Atla s 14, 2018 13 13.2 Ra infa ll De pth (inc he s) 12 12.5 11 10.1 10.2 10 T P- 40, 1961 9 USGS, 1998 8 1960 1970 1980 1990 2000 2010 2020 Ye a r Study Pub lishe d

Ne e d for Ac tion 29

Wa te rshe d Re g ula tions: F lood Mitig a tion 1,400 1983: Regulations introduced to prevent Numbe r of Struc ture s 1,200 encroachment into the 100‐ year floodplain 1,000 800 600 400 200 0 1940 1950 1960 1970 1980 1990 2000 2010 De c a de Built Count of structures in the current 100‐year floodplain by decade

Wa te rshe d Re g ula tions: F lood Mitig a tion 14,000 Hypothetical number of structures in floodplains without 12,000 Cumula tive No. Struc ture s in 12,000 regulatory protections 10,000 loodpla in 8,000 6,000 F 4,000 2,000 0 1940 1950 1960 1970 1980 1990 2000 2010 2020 De c a de Built Count of structures in the current 100‐year floodplain by decade

Re g ula tion Re vision Options 32  Do No thing  Wa it to c ha ng e re g s until flo o dpla in studie s a re fina l  Upda te re g s no w using c urre ntly a va ila b le da ta

Re de ve lopme nt e xc e ption 33  Ho w do e s this a pply to a dditio ns?  I f the ho me me e ts fre e b o a rd a nd the pro po se d to ta l sq ua re fo o ta g e do e sn’ t e xc e e d the size limita tio n, the n it ma y b e a ppro ve d unde r this e xc e ptio n