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Specific relationships for the first flush load in combined sewer flows
Per9am0n 0043-1354(95)00282-0
Wat. Re5. V01. 30, N0. 5, pp. 1244-1252, 1996 C0pyr19ht (~ 1996 E15ev1er5c1ence Ltd Pr1nted 1n 6reat 8r1ta1n. A11 r19ht5re5erved 0043-1354/96 $15.00 + 0.00
5PEC1F1C R E L A 7 1 0 N 5 H 1 P 5 F 0 R 7 H E F1R57 F L U 5 H L 0 A D 1N C 0 M 8 1 N E D 5EWER F L 0 W 5 K A P 1 L 6 U P 7 A a n d A D R 1 A N J. 5 A U L * • 7he Un1ver51ty 0f 5heff1e1d, Department 0f C1v11 and 5tructura1 En91neer1n9, Mapp1n 5treet, 5heff1e1d 51 4D7, U.K.
(F1r5t rece1ved Apr11 1995; accepted 1n rev15ed f0rm 0ct06er 1995) A65tract--Many 5tud1e5 have 1dent1f1ed the f1r5t f1u5h phen0men0n a5 6e1n9 a re1at1ve1y h19h 10ad 0f p011utant5 1n the 1n1t1a1 pha5e5 0f c0m61ned 5ewer f10w. 1n 5y5tem5 w1th0ut 5t0ra9e, th15 f1r5t f1u5h 0f p0Uutant5 may 6e d15char9ed fr0m the 5y5tem and re5u1t 1n the heavy p011ut10n 0f the rece1v1n9 waterc0ur5e. H0wever, 6y the 1nc1u510n0f a 5t0ra9e tank, th15 f1r5t f1u5h can 6e reta1ned and the eff1uent 6e d15char9ed 1n a c0ntr011ed manner. 70 0pt1m15e the 5t0ra9e v01ume, 60th the t0ta1 p011utant 10ad d15char9ed and the temp0ra1 var1at10n 1n p011utant c0ncentrat10n w1th1n an event need t0 6e pred1cted. 50ph15t1cated m0de15 11ke Q51M and M 0 U 5 E 7 R A P t0 pred1ct the p011utant5 1n ur6an 5ewer f10w5 are a1ready ava11a61e. H0wever, the data re4u1rement5 f0r the5e m0de15 are exten51ve, wh1ch u5ua11y 11m1tthe1r app11cat10n t0 maj0r 0r env1r0nmenta11y 5en51t1ve5cheme5. 7h15 paper de5cr16e5 the deve10pment 0f 51te 5pec1f1c re9re5510na1 re1at10n5h1p5t0 pred1ct the f1r5t f1u5h 10ad 0f 5u5pended 5011d51nc0m61ned 5ewer f10w and the5e may 6e u5ed f0r 5t0ra9e tank de519n. Data fr0m tw0 51te5 at 6reat Harw00d and C1ayt0n-1e-M00r51n the N0rthwe5t 0f En91and ha5 6een u5ed t0 deve10p pred1ct1ve e4uat10n5 wh1ch re1ate the f1r5t f1u5h 10ad 0f 5u5pended 5011d5and the hydr01091ca1 parameter5 m05t 11ke1yt0 1nf1uence 5ewer f10w 4ua11ty. A mu1t1p1e 5tepw15e 11near re9re5510n techn14ue ha5 6een ut1115edf0r th15 purp05e. 7he max1mum ra1nfa11 1nten51ty, max1mum 1nf10w, ra1nfa11 durat10n and the antecedent dry weather per10d were f0und t0 6e the m05t 1mp0rtant parameter5 1nf1uenc1n9 the f1r5t f1u5h 10ad 0f 5u5pended 5011d5. 7he e4uat10n5 were ver1f1ed u51n9 an 1ndependent 5et 0f data and 9ave 900d pred1ct10n5 0f the f1r5t f1u5h 10ad f0r the 51te5 c0n51dered. 7h15 5tudy ha5 the 11m1tat10nthat the e4uat10n5 are catchment 5pec1f1c. H0wever, a5 m0re data f0r d1fferent catchment5 6ec0me5 ava11a61e, 1t may 6e p055161e t0 e5ta6115h 5tandard c0eff1c1ent5 f0r app11cat10n t0 a w1de ran9e 0f catchment c0nd1t10n5. C0pyr19ht • 1996 E15ev1er 5c1ence Ltd.
Key w0rd5--ur6an run0ff p011ut10n, c0m61ned 5ewer f10w5, 5t0ra9e tank5, re9re5510n m0de1, f1r5t f1u5h, 5u5pended 5011d5
t = t 0f 5tudent5 t d15tr16ut10n 755 = t0ta1 5u5pended 5011d5 (m9/1)
N0MENCLA7URE ADWP = antecedent dry weather per10d (h) 8 0 D = 5-day, 20°C 610chem1ca1 0xy9en demand(m9/1) C 0 D = chem1ca1 0xy9en demand (m9/1) DURNff = durat10n 0f the f1r5t f1u5h (m1n) E M C f = f10w we19hted event mean c0ncentrat10n 0ver the ent1re 5t0rm durat10n (m9/1) EMCff = event mean c0ncentrat10n 1n the f1r5t f1u5h (m9/1) EMF = event mean f10w 0ver the ent1re 5t0rm durat10n (m3/5) EMFff = event mean f10w 1n f1r5t f1u5h (m3/5) FL0Wt0t = t0ta1 1nf10w (m 3) L0ADff = cumu1at1ve 10ad 0f 755 1n the f1r5t f1u5h (k9) L0ADt0t = t0ta1 10ad 0f 5u5pended 5011d5 (k9) Q1Nmax = max1mum 1nf10w rate (m3/5) Q0ut = thr0u9hf10w (m3/5) Q0ver = 0verf10w (m~/5) R 2 = 54uare 0f the mu1t1p1e c0rre1at10n c0eff1c1ent RA1Nt0t = t0ta1 ra1nfa11 depth (mm) R1N7avr = avera9e ra1nfa11 1nten51ty (mm/h) RF1N7max = max1mum ra1nfa11 1nten51ty (mm/h) 57DURN = t0ta1 5t0rm durat10n (m1n) *Auth0r t0 wh0m a11 c0rre5p0ndence 5h0u1d 6e addre55ed.
1N7R0DUC710N 7 h e f0cu5 0f u r 6 a n dra1na9e 1n the 19905 ha5 5h1fted fr0m n0t 0n1y the need t0 pr0v1de 5tructura11y 50und dra1na9e 5y5tem5 w1th a n a d e 4 u a t e hydrau11c capac1ty 6 u t a150 t0 meet env1r0nmenta1 4ua11ty 06ject1ve5 f0r rece1v1n9 waterc0ur5e5. 7 h e r e ha5 theref0re 6een a need t0 1dent1fy c05t-effect1ve m a n a 9 e m e n t 501ut10n5 a n d t0 deve10p appr0pr1ate techn1ca1 pr0cedure5 a n d t0015 f0r the c0ntr01 0 f u r 6 a n 5ewer f10w 4ua11ty. Nat10na1 pr09ramme5 0 f re5earch, f0r examp1e, the U 5 Env1r0nmenta1 Pr0tect10n A9ency•5 (EPA) Nat10na1 U r 6 a n R u n 0 f f P r 0 9 r a m m e , the U r 6 a n P011ut10n M a n a 9 e m e n t P r 0 9 r a m m e 1n the U K a n d the F r e n c h Nat10na1 P r 0 9 r a m 0n R u n 0 f f P011ut10n, have 6een carr1ed 0ut t0 addre55 the5e 155ue5, a n d the5e pr09ram5 have h19h119hted the need f0r a n 1nte9rated catchment-w1de a p p r 0 a c h t0 p011ut10n c0ntr01.
1244
1245
F1r5t f1u5h 1n c0m61ned 5ewer f10w5 70 up9rade 5ewer 5y5tem5 t0 meet the water 4ua11ty 06ject1ve5 fr0m the rece1v1n9 water5, 1t 15 fre4uent1y rec0mmended that 5t0ra9e tank5 6e 1nc0rp0rated 1nt0 the de519n 0f c0m61ned 5ewer 5y5tem5 and the5e are 0ften 10cated at the 51te 0f a c0m61ned 5ewer 0verf10w. 1n th15 re5pect, attent10n 15 0ften f0cu5ed 0n pr0v1d1n9 a 5t0ra9e tank 0f 5uff1c1ent 512e t0 reta1n the p011utant5 1n the f1r5t f1u5h. 7he c0ncept 15 0ne 0f 1nc1ud1n9 an add1t10na1 ••5t0ra9e•• v01ume f0r the attenuat10n and c0ntr01 0f 60th f10w and p011utant 10ad. Var10u5 techn14ue5 have 6een pr0p05ed t0 e5t1mate the 512e (v01ume) 0f tank. Acker5 et a1. (1968) pre5ented a de519n meth0d0109y 6a5ed 0n the v01ume 0f the dry weather f10w wh1ch wa5 0vertaken 6y the t0e 0f the advanc1n9 5t0rm wave. Hed1ey and K1n9 (1971) pr0p05ed the retent10n v01ume a5 a pr0p0rt10n 0f the de519n 5t0rm, f0r examp1e, the v01ume 0f f10w upt0 the peak f10w m1nu5 the v01ume 0f the c0nt1nuat10n f10w. C0mm0n pract1ce 1n Eur0pe (A7V, 1992) ha5 6een t0 6a5e the 512e 0f the tank 0n the retent10n 0f a 5pec1f1ed ra1nfa11 am0unt fa111n9 0n the 1mperv10u5 catchment area. 7yp1ca11y, a v01ume 0f 5t0ra9e e4u1va1ent t0 the retent10n 0f 1.5-4.0 mm 0f ra1nfa11 (15-40 m 3) per hectare 0f 1mperv10u5 area ha5 6een rec0mmended. 7h15 de519n ph11050phy ha5 6een 6a5ed 0n the re4u1rement t0 reta1n 50me 90% 0f the p011utant mater1a1 w1th1n the 5y5tem. Pre5ent1y, the preferred appr0ach 15 t0 6a5e the 512e and 10cat10n 0f the 5t0ra9e v01ume 0n env1r0nmenta1 4ua11ty 5tandard5 t0 meet a9reed env1r0nmenta1 4ua11ty 06ject1ve5 0f rece1v1n9 water5. Mathemat1ca1 51mu1at10n m0de15 t0 pred1ct the 4ua11ty 0f 5ewer f10w5 (Q51M, H R Wa111n9f0rd; and M 0 U 5 E 7 R A P , Cra6tree et a1., 1994) and the 1mpact 0f c0m61ned 5ewer 0verf10w and 0utput5 fr0m wa5tewater treatment w0rk5 0n rece1v1n9 water5 (M1KE 11, Dan15h Hydrau11c 1n5t1tute, 1992) have 6een deve10ped f0r th15 purp05e. 1t 15 n0w p055161e t0 ut1115e th15 5u1te 0f mathemat1ca1 m0de15 t0 pred1ct the effect 0f the 512e and 10cat10n 0f a 5t0ra9e tank w1th1n a part1cu1ar 5ewer 5y5tem catchment. 7he m0de15 have 6een 5h0wn t0 6e capa61e 0f pr0duc1n9 accepta61e re5u1t5. H0wever, the data c011ect10n re4u1rement5 0f the5e and 0ther deta11ed 4ua11ty m0de15 are 4u1te 0ner0u5 wh1ch 11m1t the app11cat10n 0f the5e m0de15 t0 maj0r 1nve5t19at10n5. A 51mp1er appr0ach 15 t0 e5t1mate the re4u1red 512e 0f a 5t0ra9e tank u51n9 emp1r1ca11y der1ved re1at10n5h1p5 6etween the p011utant5 (c0ncentrat10n and 10ad) 1n the 5ewer f10w and the hydr01091ca1 and catchment character15t1c5 wh1ch 1nf1uence 5ewer f10w 4ua11ty. 1n th15 paper a 5u1ta61e meth0d0109y t0 e5ta6115h the re1at10n5h1p 6etween the f1r5t f1u5h 10ad 0f 5u5pended 5011d5 1n the 5ewer f10w and the 1nf1uenc1n9 hydr01091ca1 character15t1c5 ha5 6een deve10ped 6y reference t0 data c011ected at tw0 51te5--6reat Harw00d and C1ayt0n-1e-M00r5--1n the N0rthwe5t 0f En91and.
7HE F1R57 FLU5H
7here 15 much ev1dence t0 5upp0rt the v1ew that the f1r5t f1u5h re9u1ar1y 0ccur5 1n many c0m61ned 5ewer 5y5tem5 (7h0rnt0n and 5au1, 1986) 6ut 1n 1ar9e catchment5 1t5 d15t1nct1ve 5hape may 6e 105t (5t0t2 and Krauth, 1984). 5evera1 def1n1t10n5 t0 de5cr16e the f1r5t f1u5h have 6een pr0p05ed. 7he5e 9enera11y re1ate t0 the 065ervat10n 0f h19h c0ncentrat10n5 0f 5u5pended 5ed1ment5 (and 0ther p0Uutant5) w1th1n the f1r5t part (n0t prec15e1y 5pec1f1ed) 0f the 5t0rm 0r c0m61ned 5ewer f10w. 7h0rnt0n and 5au1 (1986) def1ned the f1r5t f1u5h a5 the 1n1t1a1 per10d 0f 5t0rm f10w dur1n9 wh1ch the c0ncentrat10n 0f p011utant5 wa5 519n1f1cant1y h19her than th05e 065erved dur1n9 the 1atter 5ta9e5 0f the 5t0rm event. A typ1ca1 d15tr16ut10n 0f ra1nfa11 and the c0rre5p0nd1n9 5ewer f10w and the 5ewer f10w 4ua11ty are 5h0wn 1n F19. 1. 1n re5pect 0f t0ta1 5u5pended 5011d5 and chem1ca1 0xy9en demand, tw0 type5 0f f1r5t f1u5h were def1ned and termed 7ype A and 7ype 8. 1n a f1r5t f1u5h 0f 7ype A, the c0ncentrat10n5 0f 755 and C 0 D were 1e55 than, 0r e4ua1 t0 the c0ncentrat10n 1n the preva111n9 dry weather f10w and the h19he5t rec0rded p011utant c0ncentrat10n preceded that 0f the peak 5t0rm f10w. 1n the 7ype 8 f1u5h, c0ncentrat10n5 0f 755 and C 0 D were 9reater than the c0rre5p0nd1n9 c0ncentrat10n5 1n the preva111n9 dry weather f10w and the peak 755 and C 0 D c0ncentrat10n a1m05t c01nc1ded w1th the peak 0f 5t0rm f10w. An0ther appr0ach t0 def1ne a f1r5t f1u5h ha5 6een 6a5ed 0n the re1at10n5h1p 6etween the percenta9e 0f t0ta1 10ad and the percenta9e 0f cumu1at1ve event f10w. W1th reference t0 F19. 2, 6e19er (1987) 5u99e5ted that a f1r5t f1u5h wa5 065erved when th15 curve had an 1n1t1a1 510pe 9reater than 45 ° . 7he 45 ° 11ne repre5ented the ca5e when the c0ncentrat10n 0f 5u5pended 5011d5 rema1ned c0n5tant thr0u9h0ut the run0ff. C0nver5e1y, d11ut10n wa5 a55umed t0 0ccur when the 510pe 0f th15 11ne wa5 1e55 than 45 ° . 7he percenta9e dev1at10n 0f the cumu1at1ve 10ad curve fr0m the d1a90na1 wa5 u5ed a5 a mea5ure 0f the 5tren9th 0f the f1r5t f1u5h 0r d11ut10n and the v01ume and 10ad 1n the f1r5t f1u5h were def1ned 6y the p01nt 0f max1mum d1ver9ence fr0m the e4u1116r1um 11ne, a5 h19h119hted 1n F19. 2. 7h15 5tudy def1ne5 the f0u1 f1u5h a5 that part 0f the 5t0rm upt0 the max1mum d1ver9ence 6etween the d1men510n1e55 cumu1at1ve percenta9e 0f p011utant5 and the cumu1at1ve percenta9e 0f f10w5 p10tted a9a1n5t the cumu1at1ve percenta9e 0f t1me, a5 deta11ed 1n F19. 3.7h15 appr0ach ha5 tw0 advanta9e5. F1r5t1y, fr0m a c0ntr01 5tandp01nt, the d1men510n1e55 cumu1at1ve re1at10n f0r a part1cu1ar 51te a110w5 the en91neer t0 de519n the detent10n 5t0ra9e capac1ty nece55ary t0 capture a 91ven percent 0f 5u5pended 5011d5.5ec0nd1y, 1t 15 p055161e t0 e5t1mate the t1me 0f 0ccurrence 0f the f1r5t f1u5h wh1ch w0u1d 6e 0f c0n51dera61e 1mp0rtance when 5trate91e5 f0r the
1246
Kap11 6upta and Adr1an J. 5au1
c0ntr01 and f0rmu1ated.
mana9ement
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5U5PENDED
0f
5t0rmwater
are
50L1D5
Re5earcher5 have u5ed a 1ar9e num6er 0f parameter5 0r 1nd1cat0r5 11ke 8 0 D , C 0 D and 755 t0 e5t1mate ur6an 5t0rmwater run0ff 4ua11ty. H0wever, due t0 the h19h c05t5 1nv01ved 1n water 4ua11ty data c011ect10n and ana1y515 pr09ramme5 there 15 a need t0 11m1t the num6er 0f the5e 1nd1cat0r5. 7here 15 much ev1dence 1n 11terature 5upp0rt1n9 the u5e 0f t0ta1 5u5pended 5011d5 a5 an 1nd1cat0r 0f p011ut10n f0r ur6an dra1na9e de519n. F0r examp1e, H091and et a1. (1984) rep0rted that a 1ar9e pr0p0rt10n 0f 0ther p011utant5 5uch a5 nutr1ent5, heavy meta15, C 0 D and 0r9an1c c0mp0und5 may 6e a550c1ated w1th 5ewer 5011d5 v1a ad50rpt10n/a650rpt10n pr0ce55e5 and that upt0 90% 0f the t0ta1 ph05ph0ru5 and the 0r9an1c matter (C0D) d15char91n9 v1a 5t0rmf10w5 may 0r191nate fr0m re5u5pended p1pe dep051t5. 0ther auth0r5 (Le55ard et a1., 1982) 5h0wed that the var1at10n 0f 5u5pended 5011d5, chem1ca1 0xy9en
demand and 0rth0ph05phate5 f0110wed a 51m11ar pattern wh115t Ver6anck et a1. (1994) c0nf1rmed that heavy meta15 and 0r9an1c p011utant5 are pr1mar11y a550c1ated w1th the f1ne5t part1cu1ate5. Hence, t0 6u11d 0n th15 prev10u5 w0rk, 755 wa5 the parameter c0n51dered 1n th15 5tudy.
RE6RE5510N
57UD1E5
Prev10u5 5tud1e5, f0r examp1e, 6e19er (1987), have h19h119hted the fact0r5 that 1nf1uence the temp0ra1 var1a6111ty 1n the c0ncentrat10n and the 10ad 0f the p011utant5. 7he5e are the t1me 0f the day, the antecedent dry weather c0nd1t10n5, the 1en9th 0f the antecedent dry weather per10d, the ma9n1tude and p011utant character15t1c5 0f the dry weather and the 5t0rm f10w5, t09ether w1th the character15t1c5 0f the 5ewer 5y5tem and the 1ay0ut and 512e0f the catchment area. 1n add1t10n, the dep051ted 5ed1ment 1n 5ewer5 dur1n9 the dry weather per10d may 6e re-entra1ned and tran5p0rted d0wn5tream a5 a f1r5t f1u5h 1n the c0ncentrat10n and 10ad 0f p011utant5.
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F19. 1. A typ1ca1p10t 0f ra1nfa11run0ff p011ut09raph f0r the 6reat Harw00d 51te.(a) Ra1nfa11v5 f10wrate, and (6) temp0m1 var1at10n 0f p011utant5.
F1r5t f1u5h 1n c0m61ned 5ewer f10w5
1247
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20
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100
Curnu1aWe mn0ff (%) F19. 2. F1r5t f1u5h a5 def1ned 6y 6e19er (1987).
M a n y re5earch 5tud1e5 have 6een carr1ed 0ut u51n9 mu1t1p1e re9re5510n techn14ue5 t0 exam1ne the 1mp0rtance 0f each 0f the re1evant fact0r5 wh1ch 1nf1uence the 4ua11ty 0 f 5t0rm water f10w, f0r examp1e, De560rde5 a n d 5ervat (1984) a n d Dr1ver a n d 7 r 0 u t m a n (1989); wh115t 0ther 5tud1e5 have a t t e m p t e d t0 character15e the f1r5t f1u5h 0f p011utant5 (Pear50n et a1., 1986). H0wever, n0 ev1dence ha5 6een f 0 u n d 1n 11terature wh1ch attempt5 t0 c0m61ne the5e tw0 appr0ache5--1.e, a f1r5t f1u5h def1n1t10n c0m61ned w1th a re9re5510n a p p r 0 a c h t0 re1ate the f1r5t f1u5h 10ad t0 the hydr01091c a n d c a t c h m e n t parameter5. 7 h e w0rk pre5ented 1n th15 p a p e r attempt5 t0 e5ta6115h 5uch re9re5510na1 re1at10n5h1p5 6etween the cumu1at1ve 10ad 0 f 5u5pended 5011d5 1n the f1r5t f1u5h, the hydr01091ca1 parameter5 a n d the 5ewer f10w character15t1c5.
ME7H0D0L06Y
7he meth0d0109y ha5 6een app11ed t0 the re5u1t5 0f a f1e1dw0rk m0n1t0r1n9 pr09ramme 0f re5earch carr1ed 0ut at tw0 51te5--6reat Harw00d and C1ayt0n-1e-M00r5 1n the N0rthwe5t 0f En91and (5au1 and 7h0rnt0n, 1989). 7h15 w0rk f0rmed part 0f the U.K. Ur6an P011ut10n Mana9ement (UPM) pr09ramme 0f re5earch 1n wh1ch a
c0mprehen51ve water 4ua11ty 5amp11n9 and m0n1t0r1n9 pr09ram wa5 carr1ed 0ut 1n an attempt t0 character15e the p011ut10n 1n 60th 5t0rmwater and c0m61ned 5ewer f10w. At each 51te the 4uant1tat1ve and 4ua11tat1ve data wa5 rec0rded w1th1n an 0n-11ne 5t0ra9e tank 10cated at the d0wn5tream end 0f each 5ewer 5y5tem. 80th the cham6er5 were de519ned 1n acc0rdance w1th the rec0mmendat10n5 0ut11ned 6y Acker5 et a1. (1968). F0r each 51te, the catchment and 5t0ra9e tank character15t1c5 are h19h119hted 1n 7a61e 1 wh115t further deta115 0f 60th 51te and 1n5trumentat10n are pr0v1ded e15ewhere (7h0rnt0n and 5au1, 1986). 7he 5amp1e5 were u5ua11y ana1y5ed f0r 755, C0D, 8 0 D , NH4N and V55.7he re5u1t5 0f th15 w0rk are he1d 0n an exten51ve data 6a5e kn0wn a5 the WRc 5ewer Qua11ty Arch1ve (1987) and 0560rne and Hutch1n95 (1990) pre5ented a 5ummary 0f the data 6a5e. At 6reat Harw00d, a t0ta1 0f 230 5t0rm5 were m0n1t0red and 0f the5e 79 were deemed ••600D••, w1th a ••600D•• 5t0rm def1ned a5 0ne wh1ch had a fu11ra1nfa11rec0rd and at 1ea5t three f10w and 4ua11ty 5amp1e5. A150, the re5u1t5 0f 57 were def1ned a5 ••8E57••, a 8E57 5t0rm 6e1n9 0ne f0r wh1ch the data 1nc1uded a fu11 ra1nfa11 rec0rd, a c0mp1ete f10w rec0rd f0r at 1ea5t an h0ur, and at 1ea5t f0ur f10w and 4ua11ty data p01nt5 1n the f1r5t h0ur 0f the event. 7he t0ta1 num6er 0f 5t0rm5 rec0rded at C1ayt0n-1e-M00r5 wa5 210 and 0f the5e 71 and 52 were c1a551f1ed 1n the 6 0 0 D and 8E57 cate90ry re5pect1ve1y. 1n the pre5ent 5tudy, 0n1y the 5t0rm5 1a6e11ed ••8E57•• have 6een u5ed t0 deve10p pred1ct1ve e4uat10n5 wh1ch re1ate the f1r5t f1u5h 0f 755 t0 the hydr01091ca1 parameter5 m05t 11ke1yt0 1nf1uence 5ewer f10w 4ua11ty.
Kap11 6 u p t a and Adr1an J. 5au1
1248 100
90
4=
80
0
1
1"5
•
max1mum d1ver
30
10 0
-• 20
1
1
1
40
60
80
100
Cumu1at1ve percenta9e 01t1me Cumu1at1ve percenta9e 0f 1Dta1f10w
•
Cumu1at1Vepercenta9e 0f 1 tata1755
F19. 3. Def1n1t10n 0f the f0u1 f1u5h a5 max1mum 1t wa5 hyp0the515ed that the f1r5t f1u5h 10ad 0f p011utant5 c0u1d 6e expre55ed a5 a funct10n 0f 0ne 0r m0re 0f the f0110w1n9 var1a61e5 L0AD~ = f(EMCf, EMF,RF1N7,v,,Q1N .... RF1N7m,x,57D URN,AD W P , F L 0 W,0,).
where the var1a61e5 and n0tat10n u5ed are 5h0wn 1n 7a61e 2. 7he data wa5 5u6ject t0 re9re5510n ana1y515 (mu1t1p1e 11near and 109 tran5f0rmed 11near) t0 e5ta6115h p055161e re1at10n5h1p5 f0r the 10ad 0f 755 (1n k9) w1th1n the f1r5t f1u5h 0f p011utant5 and the var10u5 hydr01091c parameter5. 7he5e e4uat10n5 were f0rmu1ated a5 f0110w5 Y = A0 + A1X1 + A2X: + A3X~ + •
+ A,X,,
(1)
109Y = 80 + 8/109X/+ 8•,109X•, + 83109X~ + •• + 8,,109X,
(2)
d1ver9ence.
where Y = t0ta1 5u5pended 5011d5 10ad (k9), and A0, A~, A2,...,An; 80, 8~, 8., .... , 8 , , = t h e e5t1mated re9re5510n c0eff1c1ent5, and X,, refer5 t0 the var1a61e5 1n c01umn (2) 0f 7a61e 2. 7w0 5tat15t1ca1 1nd1cat0r5 were u5ed t0 exam1ne the re9re5510n re1at10n5h1p5 and the5e were the c0eff1c1ent 0f determ1nat10n (R 2) and the 5tudent•5 t-te5t. R 2 4uant1f1e5 the pr0p0rt10n 0f the data var1ance exp1a1ned 6y the m0de1. An R-• va1ue 0f 1 1nd1cate5 an exce11ent c0rre1at10n 6etween the e5t1mated and actua1 data wherea5 1f R ~ va1ue 15 0, the re9re5510n re1at10n5h1p 5h0w5 n0 c0rre1at10n, and the hyp0the515 15 1nva11dated. 1n 5ummary, theref0re the f0110w1n9 meth0d0109Y wa5 ad0pted 1n th15 5tudy: (1) a def1n1t10n 0f the f1r5t f1u5h wa5 5e1ected, (11) the var1a61e5 t0 6e u5ed 1n the ana1y515 were ch05en, (111) mu1t1p1e 11near and 109 tran5f0rmed 11near re9re5510na1 ana1y515 wa5 u5ed t0 e5ta6115h re1at10n5h1p5 6etween the var1a61e5.
7a61e 1. Catchment deta115 6reat Harw00d P0pu1at10n 12500 1mperv10u5 area (ha) 56 70ta1 area (ha) 121 Percent 1mperv10u5 46 P1pe den51ty (m/ha) 191.6 Len9th 0f ma1n 5ewer run (km) 1,931 Avera9e p1pe 9rad1ent 0,0289 Mean dry weather f10w (cumec5) 0,30 Max1mum f10w t0 treatment (cum¢c5) 0,27 5t0ra9e v01ume(m~) 138 Avera9e annua1 ra1nfa11 (mm) 1100
C1ayt0n-1e-M00r5 6500 29 40.7 70 -1.8 0.0270 0.20 0.33 126 1100
F1r5t f1u5h1n c0m61ned 5ewer f10w5
1249
7a61e 2. Var1a61e5 c0mputed fr0m the 5QA data f0r further re9re5510n ana1y515 (1) 7ype 0f parameter
(2) Var1a61e5
Event mean
F10w we19hted event mean c0ncentrat10n (m9/1) Event mean f10w (m3/5) Event mean c0ncentrat10n 1n the f1r5t f1u5h (m9/1) Avera9e ra1nfa11 1nten51ty (mm/h) Max1mum 1nf10w (m~/5) Max1mum ra1nfa11 1nten51ty (mm/h) 5t0ma durat10n (m1n) Antecedent dry weather per10d (h) 70ta1 10ad 0f 5u5pended 5011d5 (k9) 70ta1 1nf10w (m~/5) 70ta1 ra1nfa11 depth (mm) Cumu1at1ve 10ad 0f 5u5pended 5011d5 1n the f1r5t f0u1 f1u5h (k9)
Event max1mum Event t0ta1
RE5UL75 AND D15CU5510N
A5 the antecedent dry weather per10d wa5 kn0wn f0r a t0ta1 0f 36 5t0rm event5 at the 6reat Harw00d catchment and 31 event5 at the C1ayt0n-1e-M00r5 catchment 0n1y the5e 5t0rm5 were ana1y5ed 1n the w0rk pre5ented 1n th15 paper. 7he data were cate90r15ed 1nt0 5ummer (May t0 0ct06er) and w1nter (N0vem6er t0 Apr11) event5 1n 11ne w1th the rec0mmended pr0cedure5 1n the F100d 5tud1e5 Rep0rt (NERC, 1975). F0r the 5t0rm5 at 6reat Harw00d catchment, the c0mputed va1ue5 0f the mean t0ta110ad 0f 5u5pended 5011d5, t0ta11nf10w, f10w we19hted event mean c0ncentrat10n (EMCr) and the event mean f10w (EMF) are 91ven 1n 7a61e 3. 1t can 6e 5een that there were 519n1f1cantd1fference5 6etween the data f0r 5ummer and w1nter 5t0rm5 6ut n0 5tat15t1ca11y 519n1f1cant re1at10n5h1p wa5 f0und 6etween the f10w we19hted event mean c0ncentrat10n and the event mean f10w. 5u65e4uent1y, n0 c0rre1at10n wa5 f0und 6etween the f1r5t f1u5h event mean c0ncentrat10n (EMCr), event mean f10w (EMF) and the ADWP. 1t wa5 a150 hyp0the515ed that the event mean c0ncentrat10n 0f the 10ad 0f 5u5pended 5011d5 1n the f1r5t f1u5h (EMC~ wa5 re1ated t0 the 1nput var1a61e5 0f max1mum ra1nfa11 1nten51ty ( R F 1 N 7 ~ ) , avera9e ra1nfa11 1nten51ty (RF1N7a~), max1mum 1nf10w (Q1Nm~), event mean f10w upt0 f1r5t f1u5h (EMF~-), durat10n upt0 the f0u1 f1u5h (DURN,), and the t0ta1 5t0rm durat10n (57DURN) 6ut a9a1n, n0 c0rre1at10n 6etween the var1a61e5 wa5 065erved, 51m11ar1y, the re1at10n5h1p 6etween the cumu1at1ve 10ad 0f 5u5pended 5011d5 1n the f1r5t f1u5h (L0AD,) and the 1nput parameter5 Q1N .... EMF and ADWP, wa5 exam1ned and the re5u1t5 c0nf1rmed that there wa5 a9a1n 11tt1e c0rre1at10n 6etween the parameter5. A5 a next 5tep, the re1at10n5h1p 6etween the
7a61e 3. Mean va1ue5 0f p011ut10n 10ad5 and f10w f0r the 6reat Harw00d data 5t0rm type A11 5ummer W1nter
(3) N0tat10n
L0AD,0, (k9)
FL0W,0, (m 3)
EMC (m9/1)
EMF (m3/5)
696 758 635
2266 2233 2299
342 406 279
0.288 0.347 0.228
EMC~ EMF EMC~ RF1N7 ..... Q1N~ RF1N7~, 57DURN ADWP L0AD,0, FL0Wt0, RA1N,0, L0ADu
cumu1at1ve 755 1n the f1r5t f1u5h (L0AD~), the max1mum ra1nfa11 1nten51ty (RF1N7r0~x), the max1mum 1nf10w (Q1N~ax), the ADWP and the 5t0rm durat10n (57DURN) wa5 exam1ned. 7he re5u1t5 0f th15 ana1y515 are 5h0wn 1n 7a61e 4 and the f0110w1n9 pred1ct1ve e4uat10n5 were c0nc1uded: ALL 5 7 0 R M 5 (6reat Harw00d): L0AD~ = 1.58(57DURN)°~61(RF1N7m~) °7L ( A 0 W P ) °•23 (R•- = 0.59)
(1)
L0AD~r = 16.98(57DURN)°94(Q1Nm,~)°~63 ( A D W P ) °••t
(R-• = 0.59)
(2)
5UMMER 5 7 0 R M 5 (6reat Harw00d): L0AD~ = 1.35(57DURN)°~68(RF1N7m~) °~68 ( A D W P ) °8•
(R 2 = 0.65)
(3)
L0AD~ = 33.88(57DURN)°9-~(Q1Nm,~)°~47 ( A D W P ) °~
(R•• = 0.54)
(4)
W1N7ER 5 7 0 R M 5 (6reat Harw00d): L0AD~ = 3.72(57DURN)°~94(Q1Nm,x)°~93 ( A 0 W P ) °•2•
(R-• = 0.71)
(5)
L0AD~ = 0.95(57DURN)°~9-~(RF1N7~,x)°~36 ( A 0 W P ) °•2°
(R-• = 0.54).
(6)
8y exam1nat10n 0f e4uat10n5 (2)-(6), 1t can 6e 5een that the ADWP ha5 the 5ame 1nf1Uence 0n the f1r5t f1u5h p011utant 10ad 0ver the ent1re year and hence the re9re5510n ana1y515 wa5 repeated 6ut w1th0ut tak1n9 ADWP 1nt0 C0n51derat10n. 7he re5U1t5 are 5h0wn 1n 7a61e 5 and th15 re5u1ted 1n a n0t1cea61e reduct10n 1n the R• va1Ue5 ran91n9 fr0m 0.29 t0 0.45 f0r the 5ummer 5t0rm5 C0nf1rm1n9 the 1mp0rtance 0f A D W P . 1t wa5 C0nC1uded theref0re that e4uat10n5 0f the f0rm (1) and (2) are c0n51dered t0 6e the m05t appr0pr1ate t0 pred1ct the p011Utant 10ad 1n the f1r5t f1u5h.
Kap11 6upta and Adr1an J. 5aU1
1250
7a61e 4. R-"va1ue5f0r the f1r5t f1u5h10ad 0f p011utant5 a5 a funct10n 0f max1mum ra1nfa111nten51ty/f10w,5t0rm durat10n and ADWP f0r the 6reat Harw00d data L0AD5 a5 a funct10n 0f the f0110w1n9 var1a61e5 F0rm 0f e4uat10n A115t0rm5 5ummer5t0rm5 W1nter5t0rm5 RF1N7.... 57DURN, ADWP (11near) 0.52 0.55 0.62 RF1N7.... 57DURN, ADWP (109 tran5f0rm) 0.59 0.65 0.54 Q1N..... 57DURN, ADWP (11near) 0.54 0.49 0.71 Q1N.... 57DURN, ADWP (109 tran5f0rm) 0.59 0.54 0.71
7 0 further ver1fy the a60ve e4uat10n5, the ana1y515 wa5 repeated f0r the C1ayt0n-1e-M00r5 51te. 1t wa5 f0und that the w1nter 5t0rm5 d1d n0t 5h0w any mean1n9fu1 c0rre1at10n and hence 0n1y the re5u1t5 f0r the 5ummer 5t0rm5 have 6een rep0rted. 5UMMER 570RM5
(C1ayt0n-1e-M00r5)"
L 0 A D . = 0.92(57DURN)°~73(RF1N7ma~) °-93 (ADWP)
7M
(R-• = 0.71)
(7)
L 0 A D . = 103.43(57DURN)°,68(Q1Nm~x) 7 M ( A D W P ) °.~2 (R•- = 0.85).
(8)
7he re5u1t5 0f the ana1y515 at 60th the catchment5 1nd1cate the 1mp0rtance 0f the A D W P a5 a fact0r determ1n1n9 the 6u11d-up 0f p011utant5 1n the catchment and 5ewer 5y5tem. 51m11ar re5u1t5 were rep0rted, f0r examp1e, 6y Pear50n et a1. (1986), and 5t0t2 and Krauth (1984).
M0DEL VER1F1CA710N 7 h e u5efu1ne55 0f the re9re5510n m0de15 wa5 a55e55ed 6y c0mpar1n9 m0de1 re5u1t5 w1th 065erved f1r5t f1u5h 10ad5 f0r 5evera1 1ndependent 5t0rm5 n0t u5ed 1n the m0de1 ca116rat10n. A5 a11 ava11a61e data f0r the 6 r e a t H a r w 0 0 d catchment wa5 u5ed t0 deve10p the m0de1, t0 111u5trate the va11d1ty 0f the der1ved re1at10n5h1p5, e4uat10n5 (7) and (8) were app11ed t0 12 5t0rm5 at the C1ayt0n-1e-M00r5 51te wh1ch had n0t 6een 1nc1uded 1n the m0de1 f0rmu1at10n. 7 h e pred1cted and 065erved va1ue5 are 5h0wn 1n F19. 4 and 900d a9reement wa5 065erved. 1t wa5 c0nc1uded theref0re, that w1th1n the 11m1tat10n5 0f the re9re5510na1 appr0ach ad0pted, the p011utant 10ad 1n the f1r5t f1u5h may 6e pred1cted w1th rea50na61e c0nf1dence u51n9 the der1ved re1at10n5h1p5 6etween the t0ta1 5t0rm durat10n and the peak 1nf10w
0f the 5t0rm. Hence, the der1ved e4uat10n5 may 6e u5ed t0 e5ta6115h a 4u1ck e5t1mate 0f the p011utant 10ad 1n the f1r5t f1u5h 0f a c0m61ned 5ewer f10w f0r a 91ven 5t0rm durat10n, peak ra1nfa11 1nten51ty 0r f10wrate and the antecedent dry weather per10d. 1t 15 5tre55ed h0wever, that wh11e th15 meth0d0109y e11m1nate5 the need t0 e5t1mate p011utant wa5h0ff c0eff1c1ent5, the re1at10n5h1p5 der1ved are catchment 5pec1f1c. C0NCLU510N5 7 0 de5Cr16e the p011Utant 10ad W1th1n a C0m61ned 5eWer f10W 1t ha5 6een ar9Ued that t0ta1 5U5pended 5011d5 7 5 5 15 the m05t re1evant and 1mp0rtant 51n91e Var1a61e. 7he f1r5t f1U5h 0f p011Utant5 1n a C0m61ned 5eWer f10w ha5 6een def1ned a5 that part 0f the 5t0rm upt0 the max1mum d1ver9ence 6etween the d1men510n1e55 cumu1at1ve percenta9e 0f p011utant5 and the cumu1at1ve percenta9e 0f f10w p10tted a9a1n5t the cumu1at1ve percenta9e 0f t1me. 1n c0ntra5t t0 the w0rk 0f 0ther re5earcher5, 1t wa5 n0t p055161e t0 e5ta6115h 5tat15t1ca11y 519n1f1cant re1at10n5h1p5 6etween the f10w we19hted event mean c0ncentrat10n and the event mean f10w and 6etween the mean t0ta1 10ad 0f 5u5pended 5011d5, t0ta1 1nf10w, f10w we19hted event mean c0ncentrat10n and the event mean f10w. 51m11ar1y, n0 c0rre1at10n wa5 f0und 6etween the f1r5t f1u5h event mean c0ncentrat10n, event mean f10w and the antecedent dry weather per10d. M0re0ver, the event mean c0ncentrat10n 0f the 10ad 0f 5u5pended 5011d5 1n the f1r5t f1u5h wa5 f0und n0t t0 6e re1ated t0 the 1nput var1a61e5 0f max1mum ra1nfa111nten51ty, avera9e ra1nfa111nten51ty, max1mum 1nf10w, event mean f10w upt0 f1r5t f1u5h, durat10n upt0 the f0u1 f1u5h and the t0ta1 5t0rm durat10n. 7he f1r5t f1u5h 10ad wa5 5h0wn t0 c0rre1ate we11 w1th the peak ra1nfa11 1nten51ty RF1N7max (0r the peak f10wrate), the 5t0rm durat10n ( 5 7 D U R N ) and the antecedent dry weather per10d (ADWP). F0r
R-"va1ue5f0r the f1r5tf1u5h10ad 0f p011utant5 a5 a funct10n0f max1mumra1nfa111nten51ty/f10wand 5t0rm durat10n f0r the 6reat Harw00d data (w1th0ut ADWP) L0AD~ a5 f(~) F0rm 0f e4uat10n A115t0rm5 5ummer 5t0rm5 W1nter 5t0rm5 RF1N7m~, 57DURN (11near) 0.31 0.18 0.48 RF1N7m~, 57DURN (109 tran5f0rm) 0.27 0.20 0.40 Q1NN~, 57DURN (11near) 0.35 0.20 0.59 Q1N~, $7DURN (109 tran5f0rm) 0.31 0.22 0.56
7a61e 5.
1251
F1r5t f1u5h 1n c0m61ned 5ewer f10w5 L0ADff =0.922 RF1N7max exp(0.93) 57DURN exp(0.73) ADWP exp (0.14) 2000 1800 --- 1 6 0 0 .-.. 1 4 0 0
1200 •0¢- 1000 800 LE
600
m
400 200 0
1
•r•
7
1
1
1
1
"7•
1
1
1:~ 1-u3 00
1d•) 1:~ c0 c0
1d3 ~ ¢..0 00
Lt~ C0 (.0 C0
L1D (:~ L1D C0
r~ c::) L0 C0
C0 C0 ¢JD C0
00 1:~ (.0 C0
C0 C:~ t,.0 C0
c0 c:~ L1D C0
0
A
1
1
C0 t,-(.0 C0
1J•) c~ r~ C0
P~ C0 r•-C0
5mm~ date []
5r5t11u5h 10ad 0 f 7 5 5 (k9) 065erved
•
pred1cted 5r5tf1u5h 10ad (k9)
L0ADff =103.43 Q1Nrrax exp(1.74) 57DURN exp(0.68) ADWP exp (0.12)
2000.00 ,.., 1800.130 1600.(30 v 1400.00 "0 1203.00 •0e- 1000.00 = 800.00 = = 600.00
0
, 0.00
•
LE
[] [ []
J
D
200.00 0.00
~1
J
1
J
¢~ 0 C:~
~ 7-= 1•0
P~r-1d•)
C~ 0J 1d3
C3 ~ (.0
~r C-J ~
¢7 C~ 60
C0 C:) C0
r-(%J C0
L0 ~ C0
C:3 C~ ~
r,r-1d3
7t---
1.~ C0
L0 C0
L0 C0
(.0 C0
(.0 C0
t..0 C0
L0 C0
L0 C0
(.0 C0
(.0 C0
(.0 C0
P-C0
P-C0
p..
5t0rm date D 5r5tf1u5h 10ad 0 f 7 5 5 (k9)
• pred1cted 11r5tf1u5h10ad (k9)
065erved F19. 4. E4uat10n5 app11ed t0 C1ayt0n-1e-M00r5 51te data.
5ummer 5t0rm5, 1.e. th05e c0mm0n1y u5ed 1n ur6an dra1na9e de519n pract1Ce the 51te 5pec1f1C re9re5510na1 re1at10n5h1p5 def1ned were a5 f0110w5:
L 0 A D n = 1.35(57DURN)°~65(RF1N7m~x) °68 ( A D W P ) °••-8
At 6 r e a t Harw00d:
At C1ayt0n-1e-M00r5:
5UMMER 570RM5:
5UMMER 570RM5:
(R-• = 0.65).
(9)
1252
Kap11 6upta and Adr1an J. 5au1
L 0 A D ~ = 0.92(57DURN)° 73(RF1N7m, x)°~93 (A0WP)
7M
(R-• = 0.71).
Dan15h Hydrau11c 1n5t1tute (1992) Reference manua1, (10)
7 h e c0eff1c1ent5 0f the e4uat10n5 are 51te 5pec1f1c and are a funct10n 0f the catchment and 5ewer 5y5tem character15t1c5. W1th further 51m11ar ana1y515 0f data fr0m d1fferent catchment5 1t may 6e p055161e t0 e5ta6115h 5tandard c0eff1c1ent5 f0r app11cat10n t0 made t0 a ran9e 0f catchment5 and 5ewer 5y5tem5. 7he u5efu1ne55 0f the re9re5510n m0de15 wa5 a55e55ed 6y c0mpar1n9 the re5u1t5 fr0m the m0de1 w1th 065erved f1r5t f1u5h 10ad5 f0r 5evera11ndependent 5t0rm5 n0t u5ed 1n the m0de1 ca116rat10n. Rea50na61e a9reement wa5 065erved 6ut d1fference5 0f upt0 20% were 065erved. 1t wa5 c0nc1uded theref0re, that w1th1n the 11m1tat10n5 0f the re9re5510na1 appr0ach ad0pted, the p011utant 10ad 1n the f1r5t f1u5h may 6e pred1cted w1th rea50na61e c0nf1dence u51n9 the der1ved re1at10n5h1p5 6etween the t0ta1 5t0rm durat10n, the peak 1nf10w 0f the 5t0rm and the A D W P . Hence, the der1ved e4uat10n5, wh1ch at th15 5ta9e are 51te 5pec1f1c, may 6e u5ed t0 e5ta6115h a 4u1ck e5t1mate 0f the p011utant 10ad 1n the f1r5t f1u5h 0f a c0m61ned 5ewer f10w f0r a 91ven 5t0rm durat10n, peak ra1nfa11 1nten51ty 0r f10wrate and the antecedent dry weather per10d. Further w0rk 15 re4u1red t0 addre55 the 1mp0rtance 0f catchment and 5ewer 5y5tem character15t1c5 and 5uch that the meth0d0109y may 6e made m0re 9enera1. Ackn0w1ed9ement--0ne 0f the auth0r5 (K6) ackn0w1ed9e5
the rece1pt 0f a 5tudent5h1p fr0m the Un1ver51ty 0f 5heff1e1d. REFERENCE5
Acker5 P., Harr150n A. J. M. and 8rewer A. J. (1968) 7he hydrau11c de519n 0f 5t0rm 5ewa9e 0verf10w51nc0rp0rat1n9 5t0ra9e. J, 1n5t. Mun1c1pa1 En9r5 95, 31-37. A7V (1992) R1cht11n1en f11r d1e 8eme55un9 und 9e5ta1tun9 v0n Re9enent1a5tun9en 1n M15chwa55erkana115at10nen, Ar6e1t561att A128 der A7V (6u1de11ne5 A128 f0r C50 c0ntr01 de519n--6erman A550c1at10n 0f wa5tewater d15p05a1). 5t Au9u5t1n, 6FR. Cra6tree R., 6ar5da1 H., 6ent R., Mark 0. and D6r9e (1994) M 0 U 5 E 7 R A P - - a determ1n15t1c 5ewer f10w 4ua11ty m0de1. Wat. 5c1. 7echn01. 30, 107-116.
M1KE 11, DH1, Denmark.
De560rde5 M. and 5ervat E. (1984) 5011d5 1n ur6an run0ff: 5tat15t1ca1 ana1y515 0f French exper1menta1 data. Pr0c. 111 1nt. C0nf. 0n Ur6an 5t0rm Dra1na9e (Ed1ted 6y 8a1mer P., Ma1m4v15t P.A. and 5j06er9 A.), pp. 947-956. Cha1mer5 Un1ver51ty, 60te60r9, 5weden Dr1ver N. E. and 7r0utman (1989) Re9re5510n m0de15 f0r e5t1mat1n9 ur6an 5t0rm-run0ff 4ua11ty and 4uant1ty 1n the Un1ted 5tate5. J. Hydr01. 109, 221-236. 6e19er W. F. (1987) F1u5h1n9 Effect5 1n C0m61ned 5ewer 5y5tem5. Pr0c. F0urth 1nt. C0nf. 0n Ur6an 5t0rm Dra1na9e, Lau5anne, pp. 40~6. Hed1ey 6. and K1n9 M. V. (1971) 5u99e5ted c0rre1at10n 6etween 5t0rm 5ewa9e character15t1c5 and 5t0rm 0verf10w perf0rmance. Pr0c. 1CE 48, 399-411. H091and W., 8erndt550n R. and Lar50n M. (1984) E5t1mat10n 0f 4ua11ty and p011ut10n 10ad 0f c0m61ned 5ewer 0verf10w d15char9e. Pr0c. 111 1nt. C0nf. 0n Ur6an 5t0rm Dra1na9e, 66te60r9, 5weden, pp. 841-850. Le55ard P., 8er0n P. and 8r1ere F (1982) E5t1mat10n 0f water 4ua11ty 1n c0m61ned 5ewer5: the M0ntrea1 exper1ence. F1r5t 1nt. 5em1nar 0n Ur6an Dra1na9e 5y5tem5, pp. 367-375. NERC (1975) Natura1 Env1r0nment Re5earch C0unc11, F100d 5tud1e5 Rep0rt, U K . 0560rne M. P. and Hutch1n95 C. J. (1990) Data re4u1rement5 f0r ur6an water 4ua11ty m0de111n9 and 11m1tat10n5 0f the ex15t1n9 UK data6a5e. Pr0c. V 1nt. C0nf. 0n Ur6an 5t0rm Dra1na9e, 05aka, Japan, pp. 357-364. Pear50n L. 6., 7h0rnt0n R. C., 5au1 A. J. and H0ward K. (1986) An 1ntr0duct0ry ana1y515 0f the fact0r5 affect1n9 the c0ncentrat10n 0f p011utant5 1n the f1r5t f0u1 f1u5h 0f a c0m61ned 5t0rm 5ewer 5y5tem. Pr0c. 1nt. C0nf. 0n Ur6an 5t0rmwater Qua11ty and Effect5 Up0n Rece1v1n9 Water5,
Wa9en1n9en, pp. 93-102. 5au1 A. J. and 7h0rnt0n R. C. (1989) Hydrau11c perf0rmance and c0ntr01 0f p011utant5 d15char9ed fr0m a c0m61ned 5ewer 5t0ra9e 0verf10w. 1•Vat. 5c1. 7eehn01.21, 747-756. 5t0t2 6. and Krauth K. L. (1984) Fact0r5 affect1n9 f1r5t f1u5he5 1n c0m61ned 5ewer5. Pr0c. 111 1nt. C0nf. 0n Ur6an 5t0rm dra1na9e, 60te60r9, 5weden, pp. 86%878. 7h0rnt0n R. C. and 5au1 A, J. (1986) 50me 4ua11ty character15t1c5 0f c0m61ned 5ewer f10w5. Pu61. H1th En9r 14, 35-38. Ur6an P011ut10n Mana9ement Manua1 (1994) F0undat10n f0r Water Re5earch, U.K. Ver6anck M. A., A5h1ey R. M. and 8ach0c A. (1994) 1nternat10na1 W0rk5h0p 0n the 0r191n, 0ccurrence and 6ehav10ur 0f 5ed1ment5 1n 5ewer 5y5tem5: 5ummary 0f c0nc1u510n5. Wat. Re5. 28, 187-194. WRC 5ewer Qua11ty Arch1ve (1987) WRc, 5w1nd0n.
Wat. Re5. V01. 30, N0. 5, pp. 1244-1252, 1996 C0pyr19ht (~ 1996 E15ev1er5c1ence Ltd Pr1nted 1n 6reat 8r1ta1n. A11 r19ht5re5erved 0043-1354/96 $15.00 + 0.00
5PEC1F1C R E L A 7 1 0 N 5 H 1 P 5 F 0 R 7 H E F1R57 F L U 5 H L 0 A D 1N C 0 M 8 1 N E D 5EWER F L 0 W 5 K A P 1 L 6 U P 7 A a n d A D R 1 A N J. 5 A U L * • 7he Un1ver51ty 0f 5heff1e1d, Department 0f C1v11 and 5tructura1 En91neer1n9, Mapp1n 5treet, 5heff1e1d 51 4D7, U.K.
(F1r5t rece1ved Apr11 1995; accepted 1n rev15ed f0rm 0ct06er 1995) A65tract--Many 5tud1e5 have 1dent1f1ed the f1r5t f1u5h phen0men0n a5 6e1n9 a re1at1ve1y h19h 10ad 0f p011utant5 1n the 1n1t1a1 pha5e5 0f c0m61ned 5ewer f10w. 1n 5y5tem5 w1th0ut 5t0ra9e, th15 f1r5t f1u5h 0f p0Uutant5 may 6e d15char9ed fr0m the 5y5tem and re5u1t 1n the heavy p011ut10n 0f the rece1v1n9 waterc0ur5e. H0wever, 6y the 1nc1u510n0f a 5t0ra9e tank, th15 f1r5t f1u5h can 6e reta1ned and the eff1uent 6e d15char9ed 1n a c0ntr011ed manner. 70 0pt1m15e the 5t0ra9e v01ume, 60th the t0ta1 p011utant 10ad d15char9ed and the temp0ra1 var1at10n 1n p011utant c0ncentrat10n w1th1n an event need t0 6e pred1cted. 50ph15t1cated m0de15 11ke Q51M and M 0 U 5 E 7 R A P t0 pred1ct the p011utant5 1n ur6an 5ewer f10w5 are a1ready ava11a61e. H0wever, the data re4u1rement5 f0r the5e m0de15 are exten51ve, wh1ch u5ua11y 11m1tthe1r app11cat10n t0 maj0r 0r env1r0nmenta11y 5en51t1ve5cheme5. 7h15 paper de5cr16e5 the deve10pment 0f 51te 5pec1f1c re9re5510na1 re1at10n5h1p5t0 pred1ct the f1r5t f1u5h 10ad 0f 5u5pended 5011d51nc0m61ned 5ewer f10w and the5e may 6e u5ed f0r 5t0ra9e tank de519n. Data fr0m tw0 51te5 at 6reat Harw00d and C1ayt0n-1e-M00r51n the N0rthwe5t 0f En91and ha5 6een u5ed t0 deve10p pred1ct1ve e4uat10n5 wh1ch re1ate the f1r5t f1u5h 10ad 0f 5u5pended 5011d5and the hydr01091ca1 parameter5 m05t 11ke1yt0 1nf1uence 5ewer f10w 4ua11ty. A mu1t1p1e 5tepw15e 11near re9re5510n techn14ue ha5 6een ut1115edf0r th15 purp05e. 7he max1mum ra1nfa11 1nten51ty, max1mum 1nf10w, ra1nfa11 durat10n and the antecedent dry weather per10d were f0und t0 6e the m05t 1mp0rtant parameter5 1nf1uenc1n9 the f1r5t f1u5h 10ad 0f 5u5pended 5011d5. 7he e4uat10n5 were ver1f1ed u51n9 an 1ndependent 5et 0f data and 9ave 900d pred1ct10n5 0f the f1r5t f1u5h 10ad f0r the 51te5 c0n51dered. 7h15 5tudy ha5 the 11m1tat10nthat the e4uat10n5 are catchment 5pec1f1c. H0wever, a5 m0re data f0r d1fferent catchment5 6ec0me5 ava11a61e, 1t may 6e p055161e t0 e5ta6115h 5tandard c0eff1c1ent5 f0r app11cat10n t0 a w1de ran9e 0f catchment c0nd1t10n5. C0pyr19ht • 1996 E15ev1er 5c1ence Ltd.
Key w0rd5--ur6an run0ff p011ut10n, c0m61ned 5ewer f10w5, 5t0ra9e tank5, re9re5510n m0de1, f1r5t f1u5h, 5u5pended 5011d5
t = t 0f 5tudent5 t d15tr16ut10n 755 = t0ta1 5u5pended 5011d5 (m9/1)
N0MENCLA7URE ADWP = antecedent dry weather per10d (h) 8 0 D = 5-day, 20°C 610chem1ca1 0xy9en demand(m9/1) C 0 D = chem1ca1 0xy9en demand (m9/1) DURNff = durat10n 0f the f1r5t f1u5h (m1n) E M C f = f10w we19hted event mean c0ncentrat10n 0ver the ent1re 5t0rm durat10n (m9/1) EMCff = event mean c0ncentrat10n 1n the f1r5t f1u5h (m9/1) EMF = event mean f10w 0ver the ent1re 5t0rm durat10n (m3/5) EMFff = event mean f10w 1n f1r5t f1u5h (m3/5) FL0Wt0t = t0ta1 1nf10w (m 3) L0ADff = cumu1at1ve 10ad 0f 755 1n the f1r5t f1u5h (k9) L0ADt0t = t0ta1 10ad 0f 5u5pended 5011d5 (k9) Q1Nmax = max1mum 1nf10w rate (m3/5) Q0ut = thr0u9hf10w (m3/5) Q0ver = 0verf10w (m~/5) R 2 = 54uare 0f the mu1t1p1e c0rre1at10n c0eff1c1ent RA1Nt0t = t0ta1 ra1nfa11 depth (mm) R1N7avr = avera9e ra1nfa11 1nten51ty (mm/h) RF1N7max = max1mum ra1nfa11 1nten51ty (mm/h) 57DURN = t0ta1 5t0rm durat10n (m1n) *Auth0r t0 wh0m a11 c0rre5p0ndence 5h0u1d 6e addre55ed.
1N7R0DUC710N 7 h e f0cu5 0f u r 6 a n dra1na9e 1n the 19905 ha5 5h1fted fr0m n0t 0n1y the need t0 pr0v1de 5tructura11y 50und dra1na9e 5y5tem5 w1th a n a d e 4 u a t e hydrau11c capac1ty 6 u t a150 t0 meet env1r0nmenta1 4ua11ty 06ject1ve5 f0r rece1v1n9 waterc0ur5e5. 7 h e r e ha5 theref0re 6een a need t0 1dent1fy c05t-effect1ve m a n a 9 e m e n t 501ut10n5 a n d t0 deve10p appr0pr1ate techn1ca1 pr0cedure5 a n d t0015 f0r the c0ntr01 0 f u r 6 a n 5ewer f10w 4ua11ty. Nat10na1 pr09ramme5 0 f re5earch, f0r examp1e, the U 5 Env1r0nmenta1 Pr0tect10n A9ency•5 (EPA) Nat10na1 U r 6 a n R u n 0 f f P r 0 9 r a m m e , the U r 6 a n P011ut10n M a n a 9 e m e n t P r 0 9 r a m m e 1n the U K a n d the F r e n c h Nat10na1 P r 0 9 r a m 0n R u n 0 f f P011ut10n, have 6een carr1ed 0ut t0 addre55 the5e 155ue5, a n d the5e pr09ram5 have h19h119hted the need f0r a n 1nte9rated catchment-w1de a p p r 0 a c h t0 p011ut10n c0ntr01.
1244
1245
F1r5t f1u5h 1n c0m61ned 5ewer f10w5 70 up9rade 5ewer 5y5tem5 t0 meet the water 4ua11ty 06ject1ve5 fr0m the rece1v1n9 water5, 1t 15 fre4uent1y rec0mmended that 5t0ra9e tank5 6e 1nc0rp0rated 1nt0 the de519n 0f c0m61ned 5ewer 5y5tem5 and the5e are 0ften 10cated at the 51te 0f a c0m61ned 5ewer 0verf10w. 1n th15 re5pect, attent10n 15 0ften f0cu5ed 0n pr0v1d1n9 a 5t0ra9e tank 0f 5uff1c1ent 512e t0 reta1n the p011utant5 1n the f1r5t f1u5h. 7he c0ncept 15 0ne 0f 1nc1ud1n9 an add1t10na1 ••5t0ra9e•• v01ume f0r the attenuat10n and c0ntr01 0f 60th f10w and p011utant 10ad. Var10u5 techn14ue5 have 6een pr0p05ed t0 e5t1mate the 512e (v01ume) 0f tank. Acker5 et a1. (1968) pre5ented a de519n meth0d0109y 6a5ed 0n the v01ume 0f the dry weather f10w wh1ch wa5 0vertaken 6y the t0e 0f the advanc1n9 5t0rm wave. Hed1ey and K1n9 (1971) pr0p05ed the retent10n v01ume a5 a pr0p0rt10n 0f the de519n 5t0rm, f0r examp1e, the v01ume 0f f10w upt0 the peak f10w m1nu5 the v01ume 0f the c0nt1nuat10n f10w. C0mm0n pract1ce 1n Eur0pe (A7V, 1992) ha5 6een t0 6a5e the 512e 0f the tank 0n the retent10n 0f a 5pec1f1ed ra1nfa11 am0unt fa111n9 0n the 1mperv10u5 catchment area. 7yp1ca11y, a v01ume 0f 5t0ra9e e4u1va1ent t0 the retent10n 0f 1.5-4.0 mm 0f ra1nfa11 (15-40 m 3) per hectare 0f 1mperv10u5 area ha5 6een rec0mmended. 7h15 de519n ph11050phy ha5 6een 6a5ed 0n the re4u1rement t0 reta1n 50me 90% 0f the p011utant mater1a1 w1th1n the 5y5tem. Pre5ent1y, the preferred appr0ach 15 t0 6a5e the 512e and 10cat10n 0f the 5t0ra9e v01ume 0n env1r0nmenta1 4ua11ty 5tandard5 t0 meet a9reed env1r0nmenta1 4ua11ty 06ject1ve5 0f rece1v1n9 water5. Mathemat1ca1 51mu1at10n m0de15 t0 pred1ct the 4ua11ty 0f 5ewer f10w5 (Q51M, H R Wa111n9f0rd; and M 0 U 5 E 7 R A P , Cra6tree et a1., 1994) and the 1mpact 0f c0m61ned 5ewer 0verf10w and 0utput5 fr0m wa5tewater treatment w0rk5 0n rece1v1n9 water5 (M1KE 11, Dan15h Hydrau11c 1n5t1tute, 1992) have 6een deve10ped f0r th15 purp05e. 1t 15 n0w p055161e t0 ut1115e th15 5u1te 0f mathemat1ca1 m0de15 t0 pred1ct the effect 0f the 512e and 10cat10n 0f a 5t0ra9e tank w1th1n a part1cu1ar 5ewer 5y5tem catchment. 7he m0de15 have 6een 5h0wn t0 6e capa61e 0f pr0duc1n9 accepta61e re5u1t5. H0wever, the data c011ect10n re4u1rement5 0f the5e and 0ther deta11ed 4ua11ty m0de15 are 4u1te 0ner0u5 wh1ch 11m1t the app11cat10n 0f the5e m0de15 t0 maj0r 1nve5t19at10n5. A 51mp1er appr0ach 15 t0 e5t1mate the re4u1red 512e 0f a 5t0ra9e tank u51n9 emp1r1ca11y der1ved re1at10n5h1p5 6etween the p011utant5 (c0ncentrat10n and 10ad) 1n the 5ewer f10w and the hydr01091ca1 and catchment character15t1c5 wh1ch 1nf1uence 5ewer f10w 4ua11ty. 1n th15 paper a 5u1ta61e meth0d0109y t0 e5ta6115h the re1at10n5h1p 6etween the f1r5t f1u5h 10ad 0f 5u5pended 5011d5 1n the 5ewer f10w and the 1nf1uenc1n9 hydr01091ca1 character15t1c5 ha5 6een deve10ped 6y reference t0 data c011ected at tw0 51te5--6reat Harw00d and C1ayt0n-1e-M00r5--1n the N0rthwe5t 0f En91and.
7HE F1R57 FLU5H
7here 15 much ev1dence t0 5upp0rt the v1ew that the f1r5t f1u5h re9u1ar1y 0ccur5 1n many c0m61ned 5ewer 5y5tem5 (7h0rnt0n and 5au1, 1986) 6ut 1n 1ar9e catchment5 1t5 d15t1nct1ve 5hape may 6e 105t (5t0t2 and Krauth, 1984). 5evera1 def1n1t10n5 t0 de5cr16e the f1r5t f1u5h have 6een pr0p05ed. 7he5e 9enera11y re1ate t0 the 065ervat10n 0f h19h c0ncentrat10n5 0f 5u5pended 5ed1ment5 (and 0ther p0Uutant5) w1th1n the f1r5t part (n0t prec15e1y 5pec1f1ed) 0f the 5t0rm 0r c0m61ned 5ewer f10w. 7h0rnt0n and 5au1 (1986) def1ned the f1r5t f1u5h a5 the 1n1t1a1 per10d 0f 5t0rm f10w dur1n9 wh1ch the c0ncentrat10n 0f p011utant5 wa5 519n1f1cant1y h19her than th05e 065erved dur1n9 the 1atter 5ta9e5 0f the 5t0rm event. A typ1ca1 d15tr16ut10n 0f ra1nfa11 and the c0rre5p0nd1n9 5ewer f10w and the 5ewer f10w 4ua11ty are 5h0wn 1n F19. 1. 1n re5pect 0f t0ta1 5u5pended 5011d5 and chem1ca1 0xy9en demand, tw0 type5 0f f1r5t f1u5h were def1ned and termed 7ype A and 7ype 8. 1n a f1r5t f1u5h 0f 7ype A, the c0ncentrat10n5 0f 755 and C 0 D were 1e55 than, 0r e4ua1 t0 the c0ncentrat10n 1n the preva111n9 dry weather f10w and the h19he5t rec0rded p011utant c0ncentrat10n preceded that 0f the peak 5t0rm f10w. 1n the 7ype 8 f1u5h, c0ncentrat10n5 0f 755 and C 0 D were 9reater than the c0rre5p0nd1n9 c0ncentrat10n5 1n the preva111n9 dry weather f10w and the peak 755 and C 0 D c0ncentrat10n a1m05t c01nc1ded w1th the peak 0f 5t0rm f10w. An0ther appr0ach t0 def1ne a f1r5t f1u5h ha5 6een 6a5ed 0n the re1at10n5h1p 6etween the percenta9e 0f t0ta1 10ad and the percenta9e 0f cumu1at1ve event f10w. W1th reference t0 F19. 2, 6e19er (1987) 5u99e5ted that a f1r5t f1u5h wa5 065erved when th15 curve had an 1n1t1a1 510pe 9reater than 45 ° . 7he 45 ° 11ne repre5ented the ca5e when the c0ncentrat10n 0f 5u5pended 5011d5 rema1ned c0n5tant thr0u9h0ut the run0ff. C0nver5e1y, d11ut10n wa5 a55umed t0 0ccur when the 510pe 0f th15 11ne wa5 1e55 than 45 ° . 7he percenta9e dev1at10n 0f the cumu1at1ve 10ad curve fr0m the d1a90na1 wa5 u5ed a5 a mea5ure 0f the 5tren9th 0f the f1r5t f1u5h 0r d11ut10n and the v01ume and 10ad 1n the f1r5t f1u5h were def1ned 6y the p01nt 0f max1mum d1ver9ence fr0m the e4u1116r1um 11ne, a5 h19h119hted 1n F19. 2. 7h15 5tudy def1ne5 the f0u1 f1u5h a5 that part 0f the 5t0rm upt0 the max1mum d1ver9ence 6etween the d1men510n1e55 cumu1at1ve percenta9e 0f p011utant5 and the cumu1at1ve percenta9e 0f f10w5 p10tted a9a1n5t the cumu1at1ve percenta9e 0f t1me, a5 deta11ed 1n F19. 3.7h15 appr0ach ha5 tw0 advanta9e5. F1r5t1y, fr0m a c0ntr01 5tandp01nt, the d1men510n1e55 cumu1at1ve re1at10n f0r a part1cu1ar 51te a110w5 the en91neer t0 de519n the detent10n 5t0ra9e capac1ty nece55ary t0 capture a 91ven percent 0f 5u5pended 5011d5.5ec0nd1y, 1t 15 p055161e t0 e5t1mate the t1me 0f 0ccurrence 0f the f1r5t f1u5h wh1ch w0u1d 6e 0f c0n51dera61e 1mp0rtance when 5trate91e5 f0r the
1246
Kap11 6upta and Adr1an J. 5au1
c0ntr01 and f0rmu1ated.
mana9ement
707AL
5U5PENDED
0f
5t0rmwater
are
50L1D5
Re5earcher5 have u5ed a 1ar9e num6er 0f parameter5 0r 1nd1cat0r5 11ke 8 0 D , C 0 D and 755 t0 e5t1mate ur6an 5t0rmwater run0ff 4ua11ty. H0wever, due t0 the h19h c05t5 1nv01ved 1n water 4ua11ty data c011ect10n and ana1y515 pr09ramme5 there 15 a need t0 11m1t the num6er 0f the5e 1nd1cat0r5. 7here 15 much ev1dence 1n 11terature 5upp0rt1n9 the u5e 0f t0ta1 5u5pended 5011d5 a5 an 1nd1cat0r 0f p011ut10n f0r ur6an dra1na9e de519n. F0r examp1e, H091and et a1. (1984) rep0rted that a 1ar9e pr0p0rt10n 0f 0ther p011utant5 5uch a5 nutr1ent5, heavy meta15, C 0 D and 0r9an1c c0mp0und5 may 6e a550c1ated w1th 5ewer 5011d5 v1a ad50rpt10n/a650rpt10n pr0ce55e5 and that upt0 90% 0f the t0ta1 ph05ph0ru5 and the 0r9an1c matter (C0D) d15char91n9 v1a 5t0rmf10w5 may 0r191nate fr0m re5u5pended p1pe dep051t5. 0ther auth0r5 (Le55ard et a1., 1982) 5h0wed that the var1at10n 0f 5u5pended 5011d5, chem1ca1 0xy9en
demand and 0rth0ph05phate5 f0110wed a 51m11ar pattern wh115t Ver6anck et a1. (1994) c0nf1rmed that heavy meta15 and 0r9an1c p011utant5 are pr1mar11y a550c1ated w1th the f1ne5t part1cu1ate5. Hence, t0 6u11d 0n th15 prev10u5 w0rk, 755 wa5 the parameter c0n51dered 1n th15 5tudy.
RE6RE5510N
57UD1E5
Prev10u5 5tud1e5, f0r examp1e, 6e19er (1987), have h19h119hted the fact0r5 that 1nf1uence the temp0ra1 var1a6111ty 1n the c0ncentrat10n and the 10ad 0f the p011utant5. 7he5e are the t1me 0f the day, the antecedent dry weather c0nd1t10n5, the 1en9th 0f the antecedent dry weather per10d, the ma9n1tude and p011utant character15t1c5 0f the dry weather and the 5t0rm f10w5, t09ether w1th the character15t1c5 0f the 5ewer 5y5tem and the 1ay0ut and 512e0f the catchment area. 1n add1t10n, the dep051ted 5ed1ment 1n 5ewer5 dur1n9 the dry weather per10d may 6e re-entra1ned and tran5p0rted d0wn5tream a5 a f1r5t f1u5h 1n the c0ncentrat10n and 10ad 0f p011utant5.
4,00
0.600
3.50 3.00 "~-=- 2.50
0.500 0.400
E 200
0.300
150
0.200
~.
1.00 0.50
0.100 0.000
0.(30
71me (h:m) 6 M 7 1~
Re1nfa,1 1n18n51ty ~ 0 6 5 e r v e d
1nf10w 1
1800 1600 1400 ~ 12¢X1
~
12.0 7~ L~,~.~
=
755
¢
C0D
10.0
8.0 ~
~
4.0 ~"
200
~
~
....
~~=(1),(1,-~
0 ============================================================= c~ .,::. ¢M 0•) ~r u~ ~
.,::. .N. . N . . ~
~
u~ ,-
*r
,--
0.0
,9-
71me (h:m1 6M7
F19. 1. A typ1ca1p10t 0f ra1nfa11run0ff p011ut09raph f0r the 6reat Harw00d 51te.(a) Ra1nfa11v5 f10wrate, and (6) temp0m1 var1at10n 0f p011utant5.
F1r5t f1u5h 1n c0m61ned 5ewer f10w5
1247
0 "•0
nm~rnum d1ver9ence " ~
~=h"
"0 0J 0..
10
m
E e4u1116dum f1ne - un1f0rm p011utant rem0va1
t
1
1
1
1
20
40
60
80
100
Curnu1aWe mn0ff (%) F19. 2. F1r5t f1u5h a5 def1ned 6y 6e19er (1987).
M a n y re5earch 5tud1e5 have 6een carr1ed 0ut u51n9 mu1t1p1e re9re5510n techn14ue5 t0 exam1ne the 1mp0rtance 0f each 0f the re1evant fact0r5 wh1ch 1nf1uence the 4ua11ty 0 f 5t0rm water f10w, f0r examp1e, De560rde5 a n d 5ervat (1984) a n d Dr1ver a n d 7 r 0 u t m a n (1989); wh115t 0ther 5tud1e5 have a t t e m p t e d t0 character15e the f1r5t f1u5h 0f p011utant5 (Pear50n et a1., 1986). H0wever, n0 ev1dence ha5 6een f 0 u n d 1n 11terature wh1ch attempt5 t0 c0m61ne the5e tw0 appr0ache5--1.e, a f1r5t f1u5h def1n1t10n c0m61ned w1th a re9re5510n a p p r 0 a c h t0 re1ate the f1r5t f1u5h 10ad t0 the hydr01091c a n d c a t c h m e n t parameter5. 7 h e w0rk pre5ented 1n th15 p a p e r attempt5 t0 e5ta6115h 5uch re9re5510na1 re1at10n5h1p5 6etween the cumu1at1ve 10ad 0 f 5u5pended 5011d5 1n the f1r5t f1u5h, the hydr01091ca1 parameter5 a n d the 5ewer f10w character15t1c5.
ME7H0D0L06Y
7he meth0d0109y ha5 6een app11ed t0 the re5u1t5 0f a f1e1dw0rk m0n1t0r1n9 pr09ramme 0f re5earch carr1ed 0ut at tw0 51te5--6reat Harw00d and C1ayt0n-1e-M00r5 1n the N0rthwe5t 0f En91and (5au1 and 7h0rnt0n, 1989). 7h15 w0rk f0rmed part 0f the U.K. Ur6an P011ut10n Mana9ement (UPM) pr09ramme 0f re5earch 1n wh1ch a
c0mprehen51ve water 4ua11ty 5amp11n9 and m0n1t0r1n9 pr09ram wa5 carr1ed 0ut 1n an attempt t0 character15e the p011ut10n 1n 60th 5t0rmwater and c0m61ned 5ewer f10w. At each 51te the 4uant1tat1ve and 4ua11tat1ve data wa5 rec0rded w1th1n an 0n-11ne 5t0ra9e tank 10cated at the d0wn5tream end 0f each 5ewer 5y5tem. 80th the cham6er5 were de519ned 1n acc0rdance w1th the rec0mmendat10n5 0ut11ned 6y Acker5 et a1. (1968). F0r each 51te, the catchment and 5t0ra9e tank character15t1c5 are h19h119hted 1n 7a61e 1 wh115t further deta115 0f 60th 51te and 1n5trumentat10n are pr0v1ded e15ewhere (7h0rnt0n and 5au1, 1986). 7he 5amp1e5 were u5ua11y ana1y5ed f0r 755, C0D, 8 0 D , NH4N and V55.7he re5u1t5 0f th15 w0rk are he1d 0n an exten51ve data 6a5e kn0wn a5 the WRc 5ewer Qua11ty Arch1ve (1987) and 0560rne and Hutch1n95 (1990) pre5ented a 5ummary 0f the data 6a5e. At 6reat Harw00d, a t0ta1 0f 230 5t0rm5 were m0n1t0red and 0f the5e 79 were deemed ••600D••, w1th a ••600D•• 5t0rm def1ned a5 0ne wh1ch had a fu11ra1nfa11rec0rd and at 1ea5t three f10w and 4ua11ty 5amp1e5. A150, the re5u1t5 0f 57 were def1ned a5 ••8E57••, a 8E57 5t0rm 6e1n9 0ne f0r wh1ch the data 1nc1uded a fu11 ra1nfa11 rec0rd, a c0mp1ete f10w rec0rd f0r at 1ea5t an h0ur, and at 1ea5t f0ur f10w and 4ua11ty data p01nt5 1n the f1r5t h0ur 0f the event. 7he t0ta1 num6er 0f 5t0rm5 rec0rded at C1ayt0n-1e-M00r5 wa5 210 and 0f the5e 71 and 52 were c1a551f1ed 1n the 6 0 0 D and 8E57 cate90ry re5pect1ve1y. 1n the pre5ent 5tudy, 0n1y the 5t0rm5 1a6e11ed ••8E57•• have 6een u5ed t0 deve10p pred1ct1ve e4uat10n5 wh1ch re1ate the f1r5t f1u5h 0f 755 t0 the hydr01091ca1 parameter5 m05t 11ke1yt0 1nf1uence 5ewer f10w 4ua11ty.
Kap11 6 u p t a and Adr1an J. 5au1
1248 100
90
4=
80
0
1
1"5
•
max1mum d1ver
30
10 0
-• 20
1
1
1
40
60
80
100
Cumu1at1ve percenta9e 01t1me Cumu1at1ve percenta9e 0f 1Dta1f10w
•
Cumu1at1Vepercenta9e 0f 1 tata1755
F19. 3. Def1n1t10n 0f the f0u1 f1u5h a5 max1mum 1t wa5 hyp0the515ed that the f1r5t f1u5h 10ad 0f p011utant5 c0u1d 6e expre55ed a5 a funct10n 0f 0ne 0r m0re 0f the f0110w1n9 var1a61e5 L0AD~ = f(EMCf, EMF,RF1N7,v,,Q1N .... RF1N7m,x,57D URN,AD W P , F L 0 W,0,).
where the var1a61e5 and n0tat10n u5ed are 5h0wn 1n 7a61e 2. 7he data wa5 5u6ject t0 re9re5510n ana1y515 (mu1t1p1e 11near and 109 tran5f0rmed 11near) t0 e5ta6115h p055161e re1at10n5h1p5 f0r the 10ad 0f 755 (1n k9) w1th1n the f1r5t f1u5h 0f p011utant5 and the var10u5 hydr01091c parameter5. 7he5e e4uat10n5 were f0rmu1ated a5 f0110w5 Y = A0 + A1X1 + A2X: + A3X~ + •
+ A,X,,
(1)
109Y = 80 + 8/109X/+ 8•,109X•, + 83109X~ + •• + 8,,109X,
(2)
d1ver9ence.
where Y = t0ta1 5u5pended 5011d5 10ad (k9), and A0, A~, A2,...,An; 80, 8~, 8., .... , 8 , , = t h e e5t1mated re9re5510n c0eff1c1ent5, and X,, refer5 t0 the var1a61e5 1n c01umn (2) 0f 7a61e 2. 7w0 5tat15t1ca1 1nd1cat0r5 were u5ed t0 exam1ne the re9re5510n re1at10n5h1p5 and the5e were the c0eff1c1ent 0f determ1nat10n (R 2) and the 5tudent•5 t-te5t. R 2 4uant1f1e5 the pr0p0rt10n 0f the data var1ance exp1a1ned 6y the m0de1. An R-• va1ue 0f 1 1nd1cate5 an exce11ent c0rre1at10n 6etween the e5t1mated and actua1 data wherea5 1f R ~ va1ue 15 0, the re9re5510n re1at10n5h1p 5h0w5 n0 c0rre1at10n, and the hyp0the515 15 1nva11dated. 1n 5ummary, theref0re the f0110w1n9 meth0d0109Y wa5 ad0pted 1n th15 5tudy: (1) a def1n1t10n 0f the f1r5t f1u5h wa5 5e1ected, (11) the var1a61e5 t0 6e u5ed 1n the ana1y515 were ch05en, (111) mu1t1p1e 11near and 109 tran5f0rmed 11near re9re5510na1 ana1y515 wa5 u5ed t0 e5ta6115h re1at10n5h1p5 6etween the var1a61e5.
7a61e 1. Catchment deta115 6reat Harw00d P0pu1at10n 12500 1mperv10u5 area (ha) 56 70ta1 area (ha) 121 Percent 1mperv10u5 46 P1pe den51ty (m/ha) 191.6 Len9th 0f ma1n 5ewer run (km) 1,931 Avera9e p1pe 9rad1ent 0,0289 Mean dry weather f10w (cumec5) 0,30 Max1mum f10w t0 treatment (cum¢c5) 0,27 5t0ra9e v01ume(m~) 138 Avera9e annua1 ra1nfa11 (mm) 1100
C1ayt0n-1e-M00r5 6500 29 40.7 70 -1.8 0.0270 0.20 0.33 126 1100
F1r5t f1u5h1n c0m61ned 5ewer f10w5
1249
7a61e 2. Var1a61e5 c0mputed fr0m the 5QA data f0r further re9re5510n ana1y515 (1) 7ype 0f parameter
(2) Var1a61e5
Event mean
F10w we19hted event mean c0ncentrat10n (m9/1) Event mean f10w (m3/5) Event mean c0ncentrat10n 1n the f1r5t f1u5h (m9/1) Avera9e ra1nfa11 1nten51ty (mm/h) Max1mum 1nf10w (m~/5) Max1mum ra1nfa11 1nten51ty (mm/h) 5t0ma durat10n (m1n) Antecedent dry weather per10d (h) 70ta1 10ad 0f 5u5pended 5011d5 (k9) 70ta1 1nf10w (m~/5) 70ta1 ra1nfa11 depth (mm) Cumu1at1ve 10ad 0f 5u5pended 5011d5 1n the f1r5t f0u1 f1u5h (k9)
Event max1mum Event t0ta1
RE5UL75 AND D15CU5510N
A5 the antecedent dry weather per10d wa5 kn0wn f0r a t0ta1 0f 36 5t0rm event5 at the 6reat Harw00d catchment and 31 event5 at the C1ayt0n-1e-M00r5 catchment 0n1y the5e 5t0rm5 were ana1y5ed 1n the w0rk pre5ented 1n th15 paper. 7he data were cate90r15ed 1nt0 5ummer (May t0 0ct06er) and w1nter (N0vem6er t0 Apr11) event5 1n 11ne w1th the rec0mmended pr0cedure5 1n the F100d 5tud1e5 Rep0rt (NERC, 1975). F0r the 5t0rm5 at 6reat Harw00d catchment, the c0mputed va1ue5 0f the mean t0ta110ad 0f 5u5pended 5011d5, t0ta11nf10w, f10w we19hted event mean c0ncentrat10n (EMCr) and the event mean f10w (EMF) are 91ven 1n 7a61e 3. 1t can 6e 5een that there were 519n1f1cantd1fference5 6etween the data f0r 5ummer and w1nter 5t0rm5 6ut n0 5tat15t1ca11y 519n1f1cant re1at10n5h1p wa5 f0und 6etween the f10w we19hted event mean c0ncentrat10n and the event mean f10w. 5u65e4uent1y, n0 c0rre1at10n wa5 f0und 6etween the f1r5t f1u5h event mean c0ncentrat10n (EMCr), event mean f10w (EMF) and the ADWP. 1t wa5 a150 hyp0the515ed that the event mean c0ncentrat10n 0f the 10ad 0f 5u5pended 5011d5 1n the f1r5t f1u5h (EMC~ wa5 re1ated t0 the 1nput var1a61e5 0f max1mum ra1nfa11 1nten51ty ( R F 1 N 7 ~ ) , avera9e ra1nfa11 1nten51ty (RF1N7a~), max1mum 1nf10w (Q1Nm~), event mean f10w upt0 f1r5t f1u5h (EMF~-), durat10n upt0 the f0u1 f1u5h (DURN,), and the t0ta1 5t0rm durat10n (57DURN) 6ut a9a1n, n0 c0rre1at10n 6etween the var1a61e5 wa5 065erved, 51m11ar1y, the re1at10n5h1p 6etween the cumu1at1ve 10ad 0f 5u5pended 5011d5 1n the f1r5t f1u5h (L0AD,) and the 1nput parameter5 Q1N .... EMF and ADWP, wa5 exam1ned and the re5u1t5 c0nf1rmed that there wa5 a9a1n 11tt1e c0rre1at10n 6etween the parameter5. A5 a next 5tep, the re1at10n5h1p 6etween the
7a61e 3. Mean va1ue5 0f p011ut10n 10ad5 and f10w f0r the 6reat Harw00d data 5t0rm type A11 5ummer W1nter
(3) N0tat10n
L0AD,0, (k9)
FL0W,0, (m 3)
EMC (m9/1)
EMF (m3/5)
696 758 635
2266 2233 2299
342 406 279
0.288 0.347 0.228
EMC~ EMF EMC~ RF1N7 ..... Q1N~ RF1N7~, 57DURN ADWP L0AD,0, FL0Wt0, RA1N,0, L0ADu
cumu1at1ve 755 1n the f1r5t f1u5h (L0AD~), the max1mum ra1nfa11 1nten51ty (RF1N7r0~x), the max1mum 1nf10w (Q1N~ax), the ADWP and the 5t0rm durat10n (57DURN) wa5 exam1ned. 7he re5u1t5 0f th15 ana1y515 are 5h0wn 1n 7a61e 4 and the f0110w1n9 pred1ct1ve e4uat10n5 were c0nc1uded: ALL 5 7 0 R M 5 (6reat Harw00d): L0AD~ = 1.58(57DURN)°~61(RF1N7m~) °7L ( A 0 W P ) °•23 (R•- = 0.59)
(1)
L0AD~r = 16.98(57DURN)°94(Q1Nm,~)°~63 ( A D W P ) °••t
(R-• = 0.59)
(2)
5UMMER 5 7 0 R M 5 (6reat Harw00d): L0AD~ = 1.35(57DURN)°~68(RF1N7m~) °~68 ( A D W P ) °8•
(R 2 = 0.65)
(3)
L0AD~ = 33.88(57DURN)°9-~(Q1Nm,~)°~47 ( A D W P ) °~
(R•• = 0.54)
(4)
W1N7ER 5 7 0 R M 5 (6reat Harw00d): L0AD~ = 3.72(57DURN)°~94(Q1Nm,x)°~93 ( A 0 W P ) °•2•
(R-• = 0.71)
(5)
L0AD~ = 0.95(57DURN)°~9-~(RF1N7~,x)°~36 ( A 0 W P ) °•2°
(R-• = 0.54).
(6)
8y exam1nat10n 0f e4uat10n5 (2)-(6), 1t can 6e 5een that the ADWP ha5 the 5ame 1nf1Uence 0n the f1r5t f1u5h p011utant 10ad 0ver the ent1re year and hence the re9re5510n ana1y515 wa5 repeated 6ut w1th0ut tak1n9 ADWP 1nt0 C0n51derat10n. 7he re5U1t5 are 5h0wn 1n 7a61e 5 and th15 re5u1ted 1n a n0t1cea61e reduct10n 1n the R• va1Ue5 ran91n9 fr0m 0.29 t0 0.45 f0r the 5ummer 5t0rm5 C0nf1rm1n9 the 1mp0rtance 0f A D W P . 1t wa5 C0nC1uded theref0re that e4uat10n5 0f the f0rm (1) and (2) are c0n51dered t0 6e the m05t appr0pr1ate t0 pred1ct the p011Utant 10ad 1n the f1r5t f1u5h.
Kap11 6upta and Adr1an J. 5aU1
1250
7a61e 4. R-"va1ue5f0r the f1r5t f1u5h10ad 0f p011utant5 a5 a funct10n 0f max1mum ra1nfa111nten51ty/f10w,5t0rm durat10n and ADWP f0r the 6reat Harw00d data L0AD5 a5 a funct10n 0f the f0110w1n9 var1a61e5 F0rm 0f e4uat10n A115t0rm5 5ummer5t0rm5 W1nter5t0rm5 RF1N7.... 57DURN, ADWP (11near) 0.52 0.55 0.62 RF1N7.... 57DURN, ADWP (109 tran5f0rm) 0.59 0.65 0.54 Q1N..... 57DURN, ADWP (11near) 0.54 0.49 0.71 Q1N.... 57DURN, ADWP (109 tran5f0rm) 0.59 0.54 0.71
7 0 further ver1fy the a60ve e4uat10n5, the ana1y515 wa5 repeated f0r the C1ayt0n-1e-M00r5 51te. 1t wa5 f0und that the w1nter 5t0rm5 d1d n0t 5h0w any mean1n9fu1 c0rre1at10n and hence 0n1y the re5u1t5 f0r the 5ummer 5t0rm5 have 6een rep0rted. 5UMMER 570RM5
(C1ayt0n-1e-M00r5)"
L 0 A D . = 0.92(57DURN)°~73(RF1N7ma~) °-93 (ADWP)
7M
(R-• = 0.71)
(7)
L 0 A D . = 103.43(57DURN)°,68(Q1Nm~x) 7 M ( A D W P ) °.~2 (R•- = 0.85).
(8)
7he re5u1t5 0f the ana1y515 at 60th the catchment5 1nd1cate the 1mp0rtance 0f the A D W P a5 a fact0r determ1n1n9 the 6u11d-up 0f p011utant5 1n the catchment and 5ewer 5y5tem. 51m11ar re5u1t5 were rep0rted, f0r examp1e, 6y Pear50n et a1. (1986), and 5t0t2 and Krauth (1984).
M0DEL VER1F1CA710N 7 h e u5efu1ne55 0f the re9re5510n m0de15 wa5 a55e55ed 6y c0mpar1n9 m0de1 re5u1t5 w1th 065erved f1r5t f1u5h 10ad5 f0r 5evera1 1ndependent 5t0rm5 n0t u5ed 1n the m0de1 ca116rat10n. A5 a11 ava11a61e data f0r the 6 r e a t H a r w 0 0 d catchment wa5 u5ed t0 deve10p the m0de1, t0 111u5trate the va11d1ty 0f the der1ved re1at10n5h1p5, e4uat10n5 (7) and (8) were app11ed t0 12 5t0rm5 at the C1ayt0n-1e-M00r5 51te wh1ch had n0t 6een 1nc1uded 1n the m0de1 f0rmu1at10n. 7 h e pred1cted and 065erved va1ue5 are 5h0wn 1n F19. 4 and 900d a9reement wa5 065erved. 1t wa5 c0nc1uded theref0re, that w1th1n the 11m1tat10n5 0f the re9re5510na1 appr0ach ad0pted, the p011utant 10ad 1n the f1r5t f1u5h may 6e pred1cted w1th rea50na61e c0nf1dence u51n9 the der1ved re1at10n5h1p5 6etween the t0ta1 5t0rm durat10n and the peak 1nf10w
0f the 5t0rm. Hence, the der1ved e4uat10n5 may 6e u5ed t0 e5ta6115h a 4u1ck e5t1mate 0f the p011utant 10ad 1n the f1r5t f1u5h 0f a c0m61ned 5ewer f10w f0r a 91ven 5t0rm durat10n, peak ra1nfa11 1nten51ty 0r f10wrate and the antecedent dry weather per10d. 1t 15 5tre55ed h0wever, that wh11e th15 meth0d0109y e11m1nate5 the need t0 e5t1mate p011utant wa5h0ff c0eff1c1ent5, the re1at10n5h1p5 der1ved are catchment 5pec1f1c. C0NCLU510N5 7 0 de5Cr16e the p011Utant 10ad W1th1n a C0m61ned 5eWer f10W 1t ha5 6een ar9Ued that t0ta1 5U5pended 5011d5 7 5 5 15 the m05t re1evant and 1mp0rtant 51n91e Var1a61e. 7he f1r5t f1U5h 0f p011Utant5 1n a C0m61ned 5eWer f10w ha5 6een def1ned a5 that part 0f the 5t0rm upt0 the max1mum d1ver9ence 6etween the d1men510n1e55 cumu1at1ve percenta9e 0f p011utant5 and the cumu1at1ve percenta9e 0f f10w p10tted a9a1n5t the cumu1at1ve percenta9e 0f t1me. 1n c0ntra5t t0 the w0rk 0f 0ther re5earcher5, 1t wa5 n0t p055161e t0 e5ta6115h 5tat15t1ca11y 519n1f1cant re1at10n5h1p5 6etween the f10w we19hted event mean c0ncentrat10n and the event mean f10w and 6etween the mean t0ta1 10ad 0f 5u5pended 5011d5, t0ta1 1nf10w, f10w we19hted event mean c0ncentrat10n and the event mean f10w. 51m11ar1y, n0 c0rre1at10n wa5 f0und 6etween the f1r5t f1u5h event mean c0ncentrat10n, event mean f10w and the antecedent dry weather per10d. M0re0ver, the event mean c0ncentrat10n 0f the 10ad 0f 5u5pended 5011d5 1n the f1r5t f1u5h wa5 f0und n0t t0 6e re1ated t0 the 1nput var1a61e5 0f max1mum ra1nfa111nten51ty, avera9e ra1nfa111nten51ty, max1mum 1nf10w, event mean f10w upt0 f1r5t f1u5h, durat10n upt0 the f0u1 f1u5h and the t0ta1 5t0rm durat10n. 7he f1r5t f1u5h 10ad wa5 5h0wn t0 c0rre1ate we11 w1th the peak ra1nfa11 1nten51ty RF1N7max (0r the peak f10wrate), the 5t0rm durat10n ( 5 7 D U R N ) and the antecedent dry weather per10d (ADWP). F0r
R-"va1ue5f0r the f1r5tf1u5h10ad 0f p011utant5 a5 a funct10n0f max1mumra1nfa111nten51ty/f10wand 5t0rm durat10n f0r the 6reat Harw00d data (w1th0ut ADWP) L0AD~ a5 f(~) F0rm 0f e4uat10n A115t0rm5 5ummer 5t0rm5 W1nter 5t0rm5 RF1N7m~, 57DURN (11near) 0.31 0.18 0.48 RF1N7m~, 57DURN (109 tran5f0rm) 0.27 0.20 0.40 Q1NN~, 57DURN (11near) 0.35 0.20 0.59 Q1N~, $7DURN (109 tran5f0rm) 0.31 0.22 0.56
7a61e 5.
1251
F1r5t f1u5h 1n c0m61ned 5ewer f10w5 L0ADff =0.922 RF1N7max exp(0.93) 57DURN exp(0.73) ADWP exp (0.14) 2000 1800 --- 1 6 0 0 .-.. 1 4 0 0
1200 •0¢- 1000 800 LE
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5mm~ date []
5r5t11u5h 10ad 0 f 7 5 5 (k9) 065erved
•
pred1cted 5r5tf1u5h 10ad (k9)
L0ADff =103.43 Q1Nrrax exp(1.74) 57DURN exp(0.68) ADWP exp (0.12)
2000.00 ,.., 1800.130 1600.(30 v 1400.00 "0 1203.00 •0e- 1000.00 = 800.00 = = 600.00
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5t0rm date D 5r5tf1u5h 10ad 0 f 7 5 5 (k9)
• pred1cted 11r5tf1u5h10ad (k9)
065erved F19. 4. E4uat10n5 app11ed t0 C1ayt0n-1e-M00r5 51te data.
5ummer 5t0rm5, 1.e. th05e c0mm0n1y u5ed 1n ur6an dra1na9e de519n pract1Ce the 51te 5pec1f1C re9re5510na1 re1at10n5h1p5 def1ned were a5 f0110w5:
L 0 A D n = 1.35(57DURN)°~65(RF1N7m~x) °68 ( A D W P ) °••-8
At 6 r e a t Harw00d:
At C1ayt0n-1e-M00r5:
5UMMER 570RM5:
5UMMER 570RM5:
(R-• = 0.65).
(9)
1252
Kap11 6upta and Adr1an J. 5au1
L 0 A D ~ = 0.92(57DURN)° 73(RF1N7m, x)°~93 (A0WP)
7M
(R-• = 0.71).
Dan15h Hydrau11c 1n5t1tute (1992) Reference manua1, (10)
7 h e c0eff1c1ent5 0f the e4uat10n5 are 51te 5pec1f1c and are a funct10n 0f the catchment and 5ewer 5y5tem character15t1c5. W1th further 51m11ar ana1y515 0f data fr0m d1fferent catchment5 1t may 6e p055161e t0 e5ta6115h 5tandard c0eff1c1ent5 f0r app11cat10n t0 made t0 a ran9e 0f catchment5 and 5ewer 5y5tem5. 7he u5efu1ne55 0f the re9re5510n m0de15 wa5 a55e55ed 6y c0mpar1n9 the re5u1t5 fr0m the m0de1 w1th 065erved f1r5t f1u5h 10ad5 f0r 5evera11ndependent 5t0rm5 n0t u5ed 1n the m0de1 ca116rat10n. Rea50na61e a9reement wa5 065erved 6ut d1fference5 0f upt0 20% were 065erved. 1t wa5 c0nc1uded theref0re, that w1th1n the 11m1tat10n5 0f the re9re5510na1 appr0ach ad0pted, the p011utant 10ad 1n the f1r5t f1u5h may 6e pred1cted w1th rea50na61e c0nf1dence u51n9 the der1ved re1at10n5h1p5 6etween the t0ta1 5t0rm durat10n, the peak 1nf10w 0f the 5t0rm and the A D W P . Hence, the der1ved e4uat10n5, wh1ch at th15 5ta9e are 51te 5pec1f1c, may 6e u5ed t0 e5ta6115h a 4u1ck e5t1mate 0f the p011utant 10ad 1n the f1r5t f1u5h 0f a c0m61ned 5ewer f10w f0r a 91ven 5t0rm durat10n, peak ra1nfa11 1nten51ty 0r f10wrate and the antecedent dry weather per10d. Further w0rk 15 re4u1red t0 addre55 the 1mp0rtance 0f catchment and 5ewer 5y5tem character15t1c5 and 5uch that the meth0d0109y may 6e made m0re 9enera1. Ackn0w1ed9ement--0ne 0f the auth0r5 (K6) ackn0w1ed9e5
the rece1pt 0f a 5tudent5h1p fr0m the Un1ver51ty 0f 5heff1e1d. REFERENCE5
Acker5 P., Harr150n A. J. M. and 8rewer A. J. (1968) 7he hydrau11c de519n 0f 5t0rm 5ewa9e 0verf10w51nc0rp0rat1n9 5t0ra9e. J, 1n5t. Mun1c1pa1 En9r5 95, 31-37. A7V (1992) R1cht11n1en f11r d1e 8eme55un9 und 9e5ta1tun9 v0n Re9enent1a5tun9en 1n M15chwa55erkana115at10nen, Ar6e1t561att A128 der A7V (6u1de11ne5 A128 f0r C50 c0ntr01 de519n--6erman A550c1at10n 0f wa5tewater d15p05a1). 5t Au9u5t1n, 6FR. Cra6tree R., 6ar5da1 H., 6ent R., Mark 0. and D6r9e (1994) M 0 U 5 E 7 R A P - - a determ1n15t1c 5ewer f10w 4ua11ty m0de1. Wat. 5c1. 7echn01. 30, 107-116.
M1KE 11, DH1, Denmark.
De560rde5 M. and 5ervat E. (1984) 5011d5 1n ur6an run0ff: 5tat15t1ca1 ana1y515 0f French exper1menta1 data. Pr0c. 111 1nt. C0nf. 0n Ur6an 5t0rm Dra1na9e (Ed1ted 6y 8a1mer P., Ma1m4v15t P.A. and 5j06er9 A.), pp. 947-956. Cha1mer5 Un1ver51ty, 60te60r9, 5weden Dr1ver N. E. and 7r0utman (1989) Re9re5510n m0de15 f0r e5t1mat1n9 ur6an 5t0rm-run0ff 4ua11ty and 4uant1ty 1n the Un1ted 5tate5. J. Hydr01. 109, 221-236. 6e19er W. F. (1987) F1u5h1n9 Effect5 1n C0m61ned 5ewer 5y5tem5. Pr0c. F0urth 1nt. C0nf. 0n Ur6an 5t0rm Dra1na9e, Lau5anne, pp. 40~6. Hed1ey 6. and K1n9 M. V. (1971) 5u99e5ted c0rre1at10n 6etween 5t0rm 5ewa9e character15t1c5 and 5t0rm 0verf10w perf0rmance. Pr0c. 1CE 48, 399-411. H091and W., 8erndt550n R. and Lar50n M. (1984) E5t1mat10n 0f 4ua11ty and p011ut10n 10ad 0f c0m61ned 5ewer 0verf10w d15char9e. Pr0c. 111 1nt. C0nf. 0n Ur6an 5t0rm Dra1na9e, 66te60r9, 5weden, pp. 841-850. Le55ard P., 8er0n P. and 8r1ere F (1982) E5t1mat10n 0f water 4ua11ty 1n c0m61ned 5ewer5: the M0ntrea1 exper1ence. F1r5t 1nt. 5em1nar 0n Ur6an Dra1na9e 5y5tem5, pp. 367-375. NERC (1975) Natura1 Env1r0nment Re5earch C0unc11, F100d 5tud1e5 Rep0rt, U K . 0560rne M. P. and Hutch1n95 C. J. (1990) Data re4u1rement5 f0r ur6an water 4ua11ty m0de111n9 and 11m1tat10n5 0f the ex15t1n9 UK data6a5e. Pr0c. V 1nt. C0nf. 0n Ur6an 5t0rm Dra1na9e, 05aka, Japan, pp. 357-364. Pear50n L. 6., 7h0rnt0n R. C., 5au1 A. J. and H0ward K. (1986) An 1ntr0duct0ry ana1y515 0f the fact0r5 affect1n9 the c0ncentrat10n 0f p011utant5 1n the f1r5t f0u1 f1u5h 0f a c0m61ned 5t0rm 5ewer 5y5tem. Pr0c. 1nt. C0nf. 0n Ur6an 5t0rmwater Qua11ty and Effect5 Up0n Rece1v1n9 Water5,
Wa9en1n9en, pp. 93-102. 5au1 A. J. and 7h0rnt0n R. C. (1989) Hydrau11c perf0rmance and c0ntr01 0f p011utant5 d15char9ed fr0m a c0m61ned 5ewer 5t0ra9e 0verf10w. 1•Vat. 5c1. 7eehn01.21, 747-756. 5t0t2 6. and Krauth K. L. (1984) Fact0r5 affect1n9 f1r5t f1u5he5 1n c0m61ned 5ewer5. Pr0c. 111 1nt. C0nf. 0n Ur6an 5t0rm dra1na9e, 60te60r9, 5weden, pp. 86%878. 7h0rnt0n R. C. and 5au1 A, J. (1986) 50me 4ua11ty character15t1c5 0f c0m61ned 5ewer f10w5. Pu61. H1th En9r 14, 35-38. Ur6an P011ut10n Mana9ement Manua1 (1994) F0undat10n f0r Water Re5earch, U.K. Ver6anck M. A., A5h1ey R. M. and 8ach0c A. (1994) 1nternat10na1 W0rk5h0p 0n the 0r191n, 0ccurrence and 6ehav10ur 0f 5ed1ment5 1n 5ewer 5y5tem5: 5ummary 0f c0nc1u510n5. Wat. Re5. 28, 187-194. WRC 5ewer Qua11ty Arch1ve (1987) WRc, 5w1nd0n.