Soroosh Sharifi 1, Massoud Kayhanian 2, Arash Massoudieh 1. University of Birmingham. Catholic University of America. University of California, Davis

Transcription

1 Soroosh Sharifi 1, Massoud Kayhanian 2, Arash Massoudieh 1 1 Universiy of Birmingham 2 Caholic Universiy of America 3 Universiy of California, Davis

2 Background Moivaion Modelling Daa Resuls Conclusion

3

4 Green Infrasrucures (GI) Susainable Urban Drainage Sysems (SUDS) Low Impac Developmen (LID) Bes Managemen Pracices (BMP)

5 Mehods o improve and opimize he effeciveness of BMPs and LIDs Scarciy of land and economic issues; Higher removal efficiencies of he BMPs when reaing more conaminaed runoff; Less conaminaed bypassing runoff (if here is any), Take advanage of he Firs Flush

6 Firs inroduced in he 197s Release of he greaer fracion of consiuen mass or concenraion a he early par of a sorm even Caused by he quick wash-off of polluans accumulaed during dry weaher periods on he pavemen surface.

7 Dissolved Cu (ug/l) Toal Cu (ug/l) Toal Zn (ug/l) Dissolved Zn (ug/l) Firs flush of chemical consiuens are deermined from a polluograph. A polluograph presens he change in consiuen concenraion hroughou he enire sorm even (e.g., hydrograph) Time (min) 7-23, 2/11/3 Flow Rae Rainfall (in) Toal Cu Dissolved Cu Toal Zn Dissolved Zn Cu and Zn concenraion during he early runoff is nearly five imes higher han he laer sages of he rainfall 8 4

8 Rainfall or rain inensiy Flow rae Polluograph Time 6:15 7:27 8:39 9:51 11:3 12:15 13:27 14:39 Treamen Phase By-pass Phase Discharge Example BMP

9 Facors affecing he occurrence and severiy of firs flush: sorm characerisics, size and drainage characerisics of he drainage area, mobiliy and properies of polluans, lengh of he aneceden dry period Empirical Mehods e.g. Deleic and Maksimovic [1998]; Gupa and Saul [1996] Mechanisic Mehods e.g. Kang e al. [26]; Massoudieh e al. [28]

10 Various regulaory crieria have been suggesed for he reamen of capured waer volume by BMPs, referred o as waer qualiy volume (WQV). A fixed deph of runoff (Waer Qualiy Deph [WQD] ) half-inch rule requires he firs one-half inch of runoff be reaed by BMPs. A cerain fracion of he rain volume from each even. 9% rainfall even crierion, requires o capure and rea 9% of he enire rainfall volume for 24-hour design sorms on an annual basis. A cerain fracion of oal suspended solids (TSS) removed from he runoff 8% removal of TSS on an individual sorm even basis

11 No quaniaive sysemaic approach for deermining a WQD crierion has been offered ha considers uncerainies in even characerisics and he firs flush behavior of polluans during evens. Here we propose a probabilisic mehod for assessmen of he effec of sizing crieria on effluen waer qualiy, which akes ino accoun boh he uncerainies in firs flush behavior during he evens and he precipiaion paern.

12 Dimensionless cumulaive flow, V() & cumulaive consiuen mass, M(): V () T Q() d Q() d M () T Q( ) C( ) d Q( ) C( ) d M() The simples crierion for he presence of he firs flush is: M ( ) V( ) V() Load graph; Mass-Load graph; M-V graph

13 The M(V) curve can be fied by a power funcion relaively well: M ( ) [ V( )] b 1.5 b is he firs flush exponen b direcly describes he shape of he M(V) curve A firs flush occurs when b < The srengh of he firs flush can be deermined by he magniude of b No se of parameers can sufficienly explain he variaions of he consiuens recorded for all cachmens and evens

14 Q( ) C( ) d Q( ) d b M ( ) [ V ( )] M ( ) V ( ) T T Q( ) C( ) d Q( ) d Q( ) C( ) d Q( ) d Q( ) C( ) d Q( ) d T T b Subsiuing EMC T T Q( ) C( ) d Q() d Q( ) C( ) d EMC T Q() d Q() d b b 1 Differeniaing Simplifying C() EMC b T Q() d Q() d b1

15 For impervious highway drainage sysems, we can assume ha he size of he basin is small enough for is ime of concenraion o become small relaive o he ime scale of rain inensiy flucuaion. Q( ) ci( ) A C() (A = drainage area, c = runoff coefficien, i() = rainfall inensiy) EMC b T Q() d Q() d b1 b1 i() d I () C() EMC b EMC b T i() d Imax b1 I max = he even oal rainfall deph (mm) I() = cumulaive rain deph (mm) up o ime

16 WQD c. I( ) C() WQD / c EMC b Imax b1 1 b1 WQD / c EMC b for I WQD / c and b 1 max Imax Cmax EMC b for Imax WQD c and b / 1 for Imax WQD / c 2 b EMC max b1 C avg I I max max WQD c b I WQD / c for Imax WQD / c ( / ) for Imax WQD / c 3 T EMC b b L Cavg i( ) d c A I 1 max WQD / c b c A I max

17 Sie 3: Freeway 45 Three highway sies in W Cal. 5 we monioring Toal of 78 sorms Samples every 15min-1hr Samples analyzed for 35 chemical species

18 Toxic Meals: Cadmium, Chromium, Copper, Nickel, Lead, and Zinc Calculaing EMC and b, for each even Saisical Analysis (correlaion beween EMC and I max ) Fiing probabiliy densiy funcions (PDFs) b (Gamma) I max (Inverse Gaussian) 1 EMC K I max, log-normal

19 Mone Carlo Simulaion For every assumed runoff capured deph (WQD) 1, random values for b, I max, and EMC were generaed from he obained PDFs, and C max and C avr values were calculaed. California oxic rule (CTR) (U.S. EPA, 2) was used o calculae endpoin values (acue or chronic) for seleced meal consiuens. (No TMDL daa are available for he sies!) The exceedance probabiliy, P, for he capure deph: P # simulaions where C ( ) endpoin 1 # simulaions The expeced value of he number of evens per year in which he released consiuen concenraion would exceed he endpoin WQD / c C() EMC b Imax Consiuen Acue (mg/l) Chronic (mg/l) Cd.2.13 Cr Cu.7.5 Ni Pb Zn #exceeding evens / year P( average # evens / year) 1 b1

20 Exceedance probabiliy of consiuens concenraions relaive o California oxic rule waer qualiy crieria Cd (C max ) Cr (C avr ) Cu (C max ) Zn (C avr )

21 Number of evens per year in which he released maximum consiuen concenraion would exceed he endpoin. Cd (C max ) Cr (C avr ) Cu (C max ) Zn (C avr )

22 Consiuen Required WQD (mm) P < 5% P < 15% N < 1 C max C avr C max C avr C max C avr Acue Chronic Acue Chronic Acue ChronicAcue Chronic Acue Chronic Acue Chronic Cd NA 2 NA NA NA NA NA NA NA Cr 2 13 NA 2 NA NA NA NA NA NA NA NA Cu >1 >1 >1 > Ni NA 2 NA NA NA NA NA NA NA NA NA NA Pb NA 79 NA 79 NA 44 NA 43 NA 37 NA 37 Zn P: he probabiliy of exceedance for each even; N: The frequency of exceedance per year. 1 The required WQD is larger han 1 mm, bu he exac value is no calculaed here. 2 No reamen is required.

23 The approach provides a sysemaic way o quaniaively evaluae he effec of he selecion of WQD on he concenraions of various polluans discharged ino receiving waers Prioriize polluans during developmen of TMDL implemenaion plans. The mehod is capable of considering boh concenraion-based and load-based hresholds (for insances TMDL crieria).

24 Thank you! Quesions and commens?