Roa d E le va tion Stra te g y a nd Ne ig hborhood Proje c t - PowerPoint PPT Presentation

Roa d E le va tion Stra te g y a nd Ne ig hborhood Proje c t Prioritiza tion Ja nua ry 21, 2020

Me e ting Outline • Purpo se • Ja c o b s is fina lizing the ir re c o mme nda tio ns • Our te a m is he re to liste n • Use c o mme nts/ q ue stio ns re c e ive d to info rm fina l re c o mme nda tio ns • Pro viding a c o mme nt • Spe a k during the me e ting , o r • Sub mit c o mme nts/ q ue stio ns a fte r the me e ting • Co mme nt g ro und rule s during me e ting : • F o rm a line to a sk a c o mme nt/ q ue stio n • Spe a ke rs a re limite d to 2 minute s • Online vie we rs e ma il q ue stio ns to : MBRising Ab o ve @ mia mib e a c hfl.g o v BI0909191410MIA 2

Comme nts Afte r the Me e ting • Ope n c o mme nt pe rio d thro ug h Ja nua ry 24, 2020 • Que stio ns o n Citywide Sto rmwa te r Ma na g e me nt? Ple a se c o nta c t: L iz Be llo- Ma tthe ws Pub lic I nfo rma tio n Offic e r – Pub lic Wo rks De pa rtme nt 305-673-7000 e xt. 6902 E -ma il: L izBe llo -Ma tthe ws@ mia mib e a c hfl.g o v BI0909191410MIA 3

Proje c t L e a de rship 25 23 30 years years years Matt Alvarez Juan Aceituno Laurens van der Tak Project Manager Deputy Project Manager/ Climate Adaptation Implementation Task Lead Advisory Panel 20 25 15 years years years Joe Rozza Monica Diaz Jason Bird Blue-Green & Sustainability Public Outreach Planning Task Lead BI0909191410MIA 4

Ag e nda • Ro a d E le va tio n Stra te g y • Ne ig hb o rho o d Pro je c t Prio ritiza tio n • Me tho do lo g y a nd Crite ria • Que stio ns a nd Co mme nts BI0909191410MIA 5

T a sk 2 Ro a d E le va tio n Stra te g y

Wa te r se e ks its own le ve l Se a L e ve l Groundwa te r On sunny da ys, g ro undwa te r le ve ls b e lo w Mia mi Be a c h rise a nd fa ll with se a le ve l, b e c a use lime sto ne g e o lo g y c o nne c ts the o c e a n a nd g ro undwa te r. BI0909191410MIA

T ida l flooding is proble ma tic in low- lying a re a s Backflow Seepage BI0909191410MIA

T ida l F looding inc re a se d with Ra infa ll Drainage BI0909191410MIA

L ong T e rm Stra te g y inc lude s E le va te d Roa ds, Se a Wa lls a nd Pumps BI0909191410MIA

Ra ising roa ds is a n importa nt stra te g y to a ddre ss sunny da y tida l flooding in public rig ht- of- wa y • T hro ug h sto rm dra ins • T hro ug h g ro undwa te r • T hro ug h o ve rto pping o f c o a sta l b a rrie rs (e .g ., se a wa lls) • E xa c e rb a te d b y Se a L e ve l Rise (SL R) ATLANTIC BISCAYNE OCEAN INDIAN BAY CREEK BI0909191410MIA

ROADWAY HARMONIZATION: Roa d E le va tion Stra te g y Ove rvie w A roadway design approach that maintains private property access, • Inte nt of Upda te d Polic y stormwater management, and • I nc o rpo ra te upda te d tide da ta a nd SL R pro je c tio ns neighborhood aesthetics through adaptable design standards. • I mpro ve ha rmo niza tio n with priva te pro pe rty • Curre nt Polic y • Minimum ro a d c ro wn e le va tio n fo r a ll ro a ds: 3.7 ft NAVD (e sta b lishe d 2014) • Dra ft Polic y Approa c h • F le xib le de sig n o ptio ns to a ddre ss lo c a l ne e ds a nd c o nditio ns • Addre ss a c c e ss, sto rmwa te r, a nd a e sthe tic s while re duc ing flo o d risk • T ie re d ro a d e le va tio ns b a se d o n ro a d c la ssific a tio n • Alte rna tive stra te g ie s to de sig n ro a d e le va tio n b e lo w minimum e le va tio n c rite ria if c o nstra ine d b y ha rmo niza tio n with priva te pro pe rty BI0909191410MIA 12

Guiding Princ iple s of Ne w Roa d Ra ising Stra te g y • Suppo rt ke e ping ro a d surfa c e s a b o ve the king tide e le va tio n to a vo id sunny da y tida l flo o ding • E sta b lish ne w minimum e le va tio ns fo r City ro a ds b a se d o n upda te d tida l re c o rds a nd SL R pro je c tio ns • Addre ss inc re a sing g ro undwa te r e le va tio ns a nd c o nc e rn fo r po o r pa ve me nt pe rfo rma nc e , inc luding pre ma ture pa ve me nt fa ilure re la te d to sa tura te d ro a d b a se • Addre ss c o nc e rn fo r priva te pro pe rty ha rmo niza tio n • Sta nda rdize a pplic a tio n so po lic y is unb ia se d, o b je c tive , a nd tra nspa re nt • Co nside r c o st implic a tio ns BI0909191410MIA 13

Ke y F a c tors tha t Influe nc e d Curre nt 2014 Roa d E le va tion De sig n Guide line s Curre nt Roa d E le va tion Stra te g y, Re c omme nde d Roa d E le va tion = De ve lope d in 2014 A + B + C CROWN OF ROAD ELEVATION A. Histo ric a l “K ing T ide ” = 1.7 ft ensures that the highest point of NAVD* the road and important infrastructure is above rising tides. B. Se a L e ve l Rise fo r a ssume d Se rvic e L ife o f 30 ye a rs: 1.0 ft C. F re e b o a rd (1 ft a ssume d fo r ro a d c ro ss- slo pe , dra ina g e , a nd ro a d b a se ) *NAVD = No rth Ame ric a n Ve rtic a l Da tum BI0909191410MIA 14

Summa ry of Ke y F a c tors tha t De te rmine Minimum Roa d E le va tion Crite ria • E va lua te s e le va tio ns a t e dg e o f ro a d (E OR), no t c ro wn, a nd a t b o tto m o f ro a d b a se (BORB), a nd pic ks the mo st pro te c tive sta nda rd • Assume s 30-ye a r ro a d se rvic e life • Upda te d Se a L e ve l Rise pro je c tio ns • T a rg e t fre q ue nc y o f flo o ding (a pplie s a t e nd o f ro a d se rvic e life ): oc a l Roa ds : 50% c ha nc e pe r ye a r (inc lude s ro a ds c la ssifie d b y City a s • L “L o c a l”, mo stly re side ntia l ro a ds) • Ma jor Roa ds : 20% c ha nc e pe r ye a r (inc lude s ro a ds suc h a s Wa shing to n Ave . c la ssifie d a s “Mino r Arte ria l” a nd “Mino r Co lle c to r”) me rg e nc y Roa ds : 10% c ha nc e pe r ye a r (inc lude s ro a ds suc h a s Alto n Rd. • E c la ssifie d a s “E va c ua tio n Ro ute a nd a c c e ss to F irst Re spo nde rs) BI0909191410MIA 15

Upda te d de c ision proc e ss c a lc ula te s minimum roa d e le va tions a t two points on roa d se c tion BI0909191410MIA 16

Ca lc ula tion Me thod 1: L imite d F looding a t E dg e of Roa d (E OR) Measured Tides (1994-2019) at Virginia Key (ft NAVD) Tide and Sea Level (ft NAVD) Long-Term Water Surface Elevation Data at Virginia Key (25 years of hourly data) is used to estimate probability of water elevations being exceeded. BI0909191410MIA 17

Ca lc ula tion Me thod 1: L imite d F looding a t E dg e of Roa d (E OR) Water Surface Elevation at Virginia Key (ft NAVD) Water Surface Elevation (ft NAVD) 2.34 ft water elevation has 20% chance of being exceeded in any year (on average, once every 5 years). Annual Exceedance Probability BI0909191410MIA 18

Ca lc ula tion Me thod 1: L imite d F looding a t E dg e of Roa d (E OR) re sults in E OR Minimum E le va tion of 3.0 ft to 4.8 ft NAVD Relative Sea Level Change Scenarios for Miami Beach (NOAA*, 2017) SLR of 1.3 ft or 1.8 ft 30 years out from 2020, for NOAA Int-High or High Curves RSLC (ft NAVD) 30-yr service life of road *NOAA = Na tio na l Oc e a nic a nd Atmo sphe ric Administra tio n BI0909191410MIA 19

Ca lc ula tion Me thod 1: L imite d F looding a t E dg e of Roa d (E OR) re sults in E OR Minimum E le va tion of 3.0 ft to 4.8 ft NAVD BI0909191410MIA 20

Ca lc ula tion Me thod 2: L imite d Groundwa te r We tting a t Roa d Ba se during Hig h T ide (MHHW) Re sults in Bottom of Roa d Ba se (BORB) Minimum E le va tion of 2.9 ft NAVD NOAA Published MHHW of 0.2 ft NAVD for 1983-2001 epoch was updated to 0.6 ft NAVD based on recent tidal data. BI0909191410MIA 21

Hig he r of two c a lc ula tion me thods is se le c te d for E OR or BORB BI0909191410MIA 22

E me rg e nc y Roa ds ̶ Minimum E le va tion a t E dg e of Roa d (Me thod 1): 4.8 ft NAVD F o r E me rg e nc y Ro a ds, Me thod 1 re sults in hig he r Minimum E le va tio n a t E dg e o f Ro a d fo r pro je c ts b uilt in 2020. BI0909191410MIA 23

All Roa ds ̶ Minimum E le va tion of Bottom of Roa d Ba se (Me thod 2): 2.9 ft, so E dg e of Roa d is 3.9 ft a ssuming 1- ft roa d thic kne ss Me thod 2 is use d to se t Minimum E le va tio n o f Bo tto m o f Ro a d Ba se : 2.9 ft NAVD fo r pro je c ts b uilt in 2020. BI0909191410MIA 24

Ma jor Roa ds ̶ Minimum E le va tion of E dg e of Roa d (Me thod 1): 3.6 ft NAVD, so Bottom of Roa d Ba se (Me thod 2): 3.9 ft NAVD is pre fe rre d Me thod 2: L imite d Gro undwa te r/ T ida l Me thod 1: L imite d F lo o ding a t We tting a t BORB E OR F o r Ma jo r Ro a ds, Me thod 2 re sults in hig he r Minimum E le va tio n a t E dg e o f Ro a d, a ssuming pro je c ts with 1-ft ro a d thic kne ss a nd b uilt in 2020. BI0909191410MIA 25

Roa d ra ising stra te g y for future proje c ts inc re a se s in re c og nition of a c c e le ra ting Se a L e ve l Rise proje c tions Relative Sea Level Change Scenarios for Miami Beach (NOAA, 2017) SLR of 2.7 ft or 1.9 ft SLR of 3.7 ft or 2.7 ft 30 years out from 2040 30 years out from 2030 RSLC (ft (NAVD) SLR of 1.8 ft or 1.3 ft 30 years out from 2020 30-yr from 2040 30-yr from 2030 Project Start Date 2020 2025 2030 2035 2040 Emergency Roads 30-yr from 2020 4.8 5.2 5.7 6.2 6.7 (Method 1) Arterial and Local Roads 3.9 4.2 4.5 4.9 5.3 (Method 2) * * Method 2 assumes 1 ft road thickness above bottom of road base. BI0909191410MIA 26