-------
I4OO
I3OO
1200
1100
1000
900
— 800
as
. 70O
O) 600
soo
4OO
300
2OO
IOO
O
70,
60
50
«t 40
en
I
O 30
20
10
FLOW
BOD
07 03 09 10 II 12 13 14 IS 16 17 IB
7-J3-J9 I
Time '
70
60
SO
40
D
ac
30
2O
10
2.8
2.4
JC
.£
2.0 ~-
1.6
<
tr
,8
J 0
PERTINENT DATA
RUNOFF PERIOD' 07OO HRS
TO 1800 HRS 7-23- 69
TOTAL RUNOFF =
9.30 AC FT
0.097 |N
RAINFALL PERIOD' 0630 HRS
(AT R.6. No.5) TO 0745 HRS
TOTAL RAINFALL* 0.69 In
VOLUMETRIC COEFFICIENT OF
RUNOFF = 0.141
ANALYZED RUNOFF: 5.9O AC FT
(64% OF TOTAL)
RUNOFF SAMPLES5 3 GRABS
(I) O725 HRS= BOD = 37.5 mg/l
TSS =588 mg/I
(2) 0815 HRS= BOD = 36.0 mg/l
TSS ^808 mg/l
(3) 0850 HRS = BOD = 23.1 mg/l
CO
100
ao
70
60
40
U.
O
3°
20
10
VOLUMETRIC RELATIONSHIP
BOD & TSS vs. FLOW
BOD
TSS
TSS =356 mg/l
O 10 20 30 4O SO 60 TO BO 90 IOO
% OF TOTAL RUNOFF
RUNOFF CHARACTERISTICS
STATION 0-11
20th Street Storm Sewer
Figure 30 Runoff characteristics.
99
-------
"X
INTENSITY
RAINFALL
100
»0
w 80
* 70
oS
§ «
CO
_J SO
O *0
S 30
85 20
10
O
.60
.50
.40
.30
.20
.10
TIME
VOLUMETRIC RELATIONSHIP
BOD & TSS vs. FLOW
TSS
BOD
PERTINENT DATA
RUNOFF PERIOD: ITOO MRS. 5-7-69
TO 0400 MRS. 5-0-69
TOTAL RUNOFF '.
19.29 AC FT
0.171 IN
O IO 20 30 4O SO 6O 7O BO 9O IOO
% OF TOTAL RUNOFF
RAINFALL PERIOD'. 1650 HRS 5-7-69
(ATR.G. No.5) TO 2240 HRS 5-7-69
TOTAL RAINFALL= 1.14 IN
VOLUMETRIC COEFFICIENT OF
RUNOFF-0.150
ANALYZED RUNOFF! 18.75 AC FT
(97.4 OF TOTAL)
COMPOSITE PERIOD: I700HRS-
2300 HRS 5-7-69
COMPOSITE BOD = 44.8 mg/l
TSS =343 mg/l
RUNOFF CHARACTERISTICS
STATION 0-8
Ingersoll Run Overflow at Outlet
Figure 30. Runoff characteristics. (Continued)
100
-------
EOOO
1900 •
iaoo
JTOO
1600
I50O
I40O
1300
12OO
_ II OO
o>
^ IOOO
-I
u
=3 90°
oo
TOO
60O
soo
40O
3OO
ZOO
IOO
0
IOO)
9OJ
8O
7O
Q
§ 50
4O
10
20
IO
O
6.O
5.0
4.O
3.O U.
U.
O
QC
z.o
I.O
ZO 22 24 O2 04 OS 03 10 12 14 16 18 2O
I -15-69
I - 16 - 69
Time
PERTINEIMT DATA
RUNOFF PERIOD : 1800 HRS I- 15-69
TO 1800 HRS I-16-69
PRECIPITATION : NONE - SNOW MELT
COMPOSITE PERIOD : SAME AS ABOVE
COMPOSITE
BOD = 31 mg/l
TSS = 302 mg/l
CL~= 100 mg/l
RUNOFF CHARACTERISTICS
STATION S- 3
Cummins ParkwayStorm Sewer
Figure 30. Runoff characteristics.
101
-------
Studies in Seattle, Washington in 1971 also generated information on com-
bined sewer overflow pollutant concentrations versus time. (59) A plot of these
data with flow and rainfall intensity is shown in Figures 31 and 32. These
show that solids concentrations increase to a peak subsequent to the flow peak
"Ml
o
si 'aaoavHasia sanosivioi
o.
a
C
a.
ui
ui
1
•a
to
O
LL
a
to
_c
.a
o
O
fi C
fO
50
K ""
5 en
o o
o J«
II
•- y.
"
-------
qi 'paBjeqosia dOO 'QOB I8*0!
a
Z
t
e
a
a.
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w
a
I
S 01
II
IS IS
so
e ID
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OZ
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sp'MOld
experienced while COD and BOD peak very early and diminish with increasing
flow—a condition consistent with the first-flush phenomenon. It should be
recognized that these data, however, are for an overflow and do not as such,
indicate flows and pollutant strengths during the first hour of rainfall
where first-flush characteristics may be better defined.
103
-------
Detailed tabulation of the characteristics of the first flush phenomenon
are also found in the literature on combined sewer overflow investigations.
Results of a monitoring program for the District of Columbia are plotted in
Figure 33 and shown in Table 51. (60) As shown in the table, the sampling
occurred at relatively small time steps, the data clearly demonstrated the
gradual changes in concentrations of each of the contaminants.
• BOD
O COD
m Total Solids
Suspended Solids
0 Flow
(75,000)
4732 l/*ec
(70,000)
4416
(65,000)
4101
(60,000)
3784
(55,000)
3470
(50,000)
3154
(45,000)
2839
(40,000)
2524
(35,000)
2208
(30,000)
1893
(25,000)
' 1577
(20,000)
• 1262
(15,000)
• 946
(10,000)
' 631
, (5000)
315
20 40 60 80 100
120
140
160
Figure 33 Flow, BOD, COD, Total Solids, Suspended Solids
Source: Roy F. Watson, Inc., "Combined Sewer Overflow Abatement Alternatives, Washington, D.C.," USEPA Report
No, 1024EXFO8/70 (NTIS No. PB 203 680), August, 1970.
An analysis of the mass emission (not shown) indicates that after 30
minutes the rate of discharge of the key pollutants is minimal.
104
-------
TABLE 51. CHARACTERISTICS OF COMBINED SEWER OVERFLOWS IN
SEWER DISTRICT GOOD HOPE RUN, DISTRICT OF COLUMBIA
Location of Sampling Site - 17 Minn, and 16 S.E.
Date
July 28
July 28
August 2
Storm
Total Sampling
Rainfall Interval
Time in cm min
1:20-2:00 p.m. 1.6 4.1 5
5
5
5
5
5
5
5
5
5
5
5
10
10
10
10
35
10
10
10
30
5:00-5:30 p.m. 0.20 0.5 10
10
10
10
10
10
10
10
8: 17-9:30 p.m. 2.9 7.4 10
10
10
10
10
10
10
10
10
" 10
10
Elapsed
Time
min
0
5
10
15
20
25
30
35
40
45
50
55
60
70
80
90
100
135
145
155
165
195
0
10
20
30
40
50
60
•70
80
0
10
20
30
40
50
60
70
80
90
100
110
Flow pH
gpm I/sec
21,000
65,600
75,000
67,900
47,700
43,300
57,900
15,400
12,500
10,200
7,900
6,090
4,570
5,000
3,740
3,620
4,770
2,020
2,625
2,190
3,180
1,140
2,020
2,500
4,010
2,640
3,600
4,200
3,090
1,640
2,020
34,400
16,800
10,100
5,660
4,400
3,520
2,470
1,960
1,995
1,601
1,410
1,340
1,325 6.2
4,140 6.2
7,730 6.1
3,655 6.0
3,010 6.1
2,730 6.0
3,655 6.0
970 6.2
790 6.2
645 6.3
500 6.2
385 6.3
290 6.4
315 6.3
235 6.6
230 6.8
300 6.9
130 7.0
165 6.3
140 7.0
200 7.0
70 7.1
130 7.0
160
255 6.9
165 7.0
230 7.1
265 7.1
195 7.1
105 7.2
130 7.1
2,170 6.3
1,060 6.3
640 6.2
360 6.2
280 6.5
220 6.6
155 6.8
125 6.9
125 7.0
100 7.0
90 7.0
85 7.1
COD
mg/l
430
400
280
170
310
300
370
240
230
210
210
230
150
120
140
120
53
48
67
77
67
29
58
96
77
77
48
106
86
77
38
400
259
210
140
184
119
108
140
129
65
86
54
BOD
mg/l
13
15
11
16
15
15
5
8
13
15
16
4
15
17
14
14
12
4
4
5
8
3
4
6
7
5
5
5
5
4
3
16
12
36
16
36
17
12
31
13
40
14
17
Total
Solids
mg/l
14,600
12,560
6,638
5,830
10,002
10,682
10,242
8,676
7,198
6,092
4,898
4,598
3,908
2,898
2.310
1,670
1,454
1,140
770
944
776
778
578
488
446
539
1.070
1,842
1,580
1,984
1,240
10,346
6,626
4,290
3,318
2,478
1,838
1,090
1,290
1,342
680
1,130
910
Total
Volatile
Solids
mg/l
912
996
278
268
600
484
512
488
460
390
288
378
284
228
200
110
136
136
138
136
76
142
90
90
151
96
120
136
84
12
106
538
368
250
226
188
180
40
184
178
164
200
72
Suspended
Solids
mg/l
9,600
11,200
6,050
5,520
9,020
10,010
9,170
8,150'
5,560
5,900
4,620
3,920
3,140
2,160
1,920
1,020
1,160
640
480
720
480
520
380
320
300
340
920
1,500
1,300
1,740
980
9,568
6,560
4,210
2,610
1,200
1,550
1,278
910
840
200
548
416
Volatile
Suspended
Solids
mg/l
880
860
60
40
430
370
380
410
460
210
180
280
300
180
200
50
100
120
100
120
-
100
100
100
120
100
120
180
160
180
140
524
210
250
50
70
80
232
60 .
20
0
40
12
Settleable
Solids
mg/l
6,756
7.640
3,330
2,660
6,528
6,906
5,702
6,662
2.912
2,332
2,530
3,616
2,792
1.016
1.036
360
524
-
—
396
280
200
248
144
192
157
472
812
708
984
496
5,353
4,700
2,370
1,290
710
1,060
480
662
,. 700
40
400
268
Total P
mg/l
4.5
2.8
1.5
1.8
2.4
2.0
2.6
1.6
1.8
2.2
2.0
1.6
1.6
1.5
1.4
2.1
1.0
1.0
0.5
1.0
1.0
0.4
0.3
0.4
0.4
1.8
1.0
0.8
0.4
0.2
0.2
2.0
1.8
1.5
1.0
1.0
1.0
1.0
1.0
1.4
0.4
0.2
0.4
Total N
mg/l
4.0
2.8
2.5
2.5
4.0
2.5
3.0
2.5
2.0
3.2
3.0
2.0
2.2
1.8
2.0
2.0
1.6
1.4
1.5
2.4
1.2
1.6
2.0
1.6
1.4
3.4
1.2
1.2
1.2
1.2
1.0
4.0
4.0
2.5
2.0
2.0
1.5
2.0
1.6
1.0
1.0
1.0
0.6
Roy F. W.tion. Inc., "Comblnix) Sowir Ov.rilow A0«tom«nt Alurnstlvot. Wllhlngton, D.C.." USEPA Roport No. 1024EXF08/70 (NTIS No. PB 203 680). Augutt. 1970.
-------
A summary of data from a study of urban freeway drainage is presented in
Table 52. ,(59) This shows that a first flush effect occurs at the beginning
of storm runoff. Relatively high concentrations of contaminants, particularly
suspended solids, COD, and settleable solids can be observed early in the run-
off, then diminishes rapidly after 15 to 30 minutes.
TABLE 52. URBAN FREEWAY DRAINAGE WATER QUALITY
(Seattle)
D»te
3.2-70
36.70
Tims Since
Last Rain
12 days
3 days
Time After
Start of
Runoff
0-15 min.
15-30 min.
30-40 min.
0-20 min.
4hrs.
8hrs.
12hrs.
Suspended
Solids
mg/l
1494
25
11
504
177
228
141
Settleable
Solids
mg/l
31.0
<0.1
<0.1
1.1
0.2
0.7
0.2
COD
mg/l
1617
909
893
222
185
150
103
BOD
mg/l
198
181
162
22
21
9
12
NO2 + NO3
Nitrogen
mgN/l
2.52
2.50
2.45
0.58
1.00
0.38
0.51
Total
P04
Soluble
mgP/l
.37
.18
.16
.33
.28
.20
.16
Free
NH3
mg N/l
.01
.01
.01
.18
.20
.09
.11
Oil
mg/l
55.0
16.0
18.0
55.0
47.0
27.0
30.0
Source: Municipality of Metropolitan Seattle "Maximizing Storage in Combined Sewer Systems," US EPA Report 11022ELK12/71
(NTIS No. PB209861), December, 1971.
Comparisons of the quality characteristics from a first-flush and an extended
overflow period, are also reported on in a study of the existing combined sewer
system in the City of Milwaukee, Wisconsin. The findings are shown in Table 53.
TABLE 53. COMPARISON OF
QUALITY CHARACTERISTICS FROM FIRST-FLUSH AND
EXTENDED, COMBINED-OVERFLOW DATA
Concentration
During First Flush1
Concentration of
Extended Overflow2
Analysis
COD
BOD
Total Solids
Total Volatile Solids
Suspended Solids
Volatile Suspended Solids
Total Nitrogen
Ortho-Phosphate
PH
Coliform Density per ml
(x 103/ml)
Data represent 12 overflows at 95 percent confidence level range.
2 Data represent 44 overflows at 95 percent confidence level range.
Source: Rex Chainbelt, Inc., "Screening/Flotation Treatment of Combined
Sewer Overflows," USEPA Report No. 11020FDC01/72 (NTIS No.
PB215 695), January, 1972
106
581 ± 92
1 86 ± 40
861 ±117
489 ± 83
522+150
308 ± 83
17.6 + 3.1
2.7 + 1.0
7.0 ±0.1
142 ± 108 x 103
161 ±19
49+ 10
378 ± 46
185 + 23
1 66 ± 26
90 ±14
5.5 ± 0.8
—
7.2 + 0.1
62.5 ± 27 x 103
-------
As may be expected, the quality of the combined sewer overflow changed
rapidly after the end of the first flush period. According to the findings, the
period persisted for about 20 to 70 minutes after the storm runoff began. (61)
The first-flush effect can also be disclosed by the efficiency of pollutant
removal in a wastewater treatment unit process. Tables 54 and 55
present the results of the operation of a demonstration unit in the treatment
system. Removal of BOD, COD, suspended solids, and volatile suspended solids
TABLE 54. COMBINED SEWER OVERFLOW POLLUTANT
REMOVAL BY SCREENING
SCREEN MESH 50 (297^)
Removal During Removal During
Pollutant First Flushing %l Extended Overflows %2
COD
BOD5
Suspended Solids
Volatile Suspended Solids
39 ±15
33 ±17
36 ±16
37 ±18
26 ±5
27 ±5
27 ±5
34±5
Represents 8 overflows
2
Represents 46 overflows
Data at 95 percent confidence level
Source: Rex Chainbelt, Inc., "Screening/Flotation Treatment of Combined Sewer
Overflows," USEPA Report No. 11020FDC01/72 (NTIS No. PB 215695),
January, 1972.
TABLE 55. COMBINED SEWER OVERFLOW
POLLUTANT REMOVALS BY SCREENING/FLOTATION
Removal During Extended Overflows — %2
Without Chemical With Chemical With Chemical
Pollutant
COD
BODg
Suspended Solids
Volatile Suspended Solids
Total Nitrogen
During First
Flushes %1
64 + 6
55 ±8
72 + 6
75 ±6
46 ±7
Flocculants
(1969-1 970 Data)
41 ±8
35 ±8
43 ±7
48 ±11
29 ±14
Flocculants
{1969 Data)3
40 ±14
46 ±17
59±11
58 ±10
19±11
Flocculants
(1970 Data)4
57 ±11
60 ±11
71 ±9
71 ±9
24 ±9
All data at 95 percent confidence level
Overflow Rate ~190 I/m2/min {2.5 gpm/ft2)
Represents 12 overflows
Represents 38 overflows
32.5 — 3.5 mg/l C31 Dow Polyelectrolyte, 6 rog/l Clay
43-6 mg/l C31, 20-25 mg/l FeCI3
Source:
Rex Chainbelt, Inc., "Screening/Flotation Treatment of Combined Sewer Overflows," USEPA Report No. 11020FDC01 /72
(NTIS No. PB 215 697), January, 1972.
107
-------
in the screening operation during the first-flush were in the range of 30 to
40 percent. During the extended overflows period, removal efficiencies drop-
ped to the 20 to 30 percent level. In the operation of the screening flotation
system, the percentage removal of contaminants during the first-flush period
was generally higher than during extended overflows, except during use of
chemical flocculants in 1970 (61) due to the operating characteristics of
the treatment method.
First-flush occurences appear to be related to the length of time between
overflows. The study conducted in the City of Milwaukee demonstrates the
effects of the length of time between overflows on the concentrations of con-
taminants in combined sewer overflows. The results of the study are shown in
Tables 56 and 57.
TABLE 56. FIRST-FLUSH EVALUATIONS
Days Since COD (mg/l)
Last Overflow Mean a
0
1
2
3
4
5
6
8
11
17
19
178.1
122.5
139.0
164.9
78.0
221.5
316.0
716.0
301.3
267.0
353.0
39.9
57.2
43.4
62.1
—
198.7
224.7
288.5
301.2
26.9
26.9
N
8
10
6
7
1
2
3
2
3
2
2
BOD (mg/l)
Mean a N
50.1
26.8
45.3
51.0
12.0
101.0
60.0
170.0
135.3
113
134.5
21.3
15.3
20.3
29.5
—
—
41.5
14.1
168.6
—
14.8
7
8
4
3
1
1
3
2
3
1
2
SS (mg/l)
Mean a
192.5
119.4
127.7
150.7
208.0
364.0
295.3
805.5
470.4
214.5
297.5
99.6
43.3
23.1
86.8
—
186.7
232.4
529.6
431.0
70.0
166.2
N
8
9
6
7
1
2
3
2
5
2
2
VSS (mg/l)
Mean a
100.6
68.4
63.8
95.6
66.0
196.0
178.7
462.5
131.0
140.5
205.5
44.9
17.8
46.2
—
80.6
130.1
304.8
140.1
33.2
95.5
N
8
10
6
7
1
2
3
2
3
2
2
a - standard deviation
N ™ number of samples
Source:
Rex Choinbolt, Inc., "Screen/Flotation Treatment of Combined Sewer Overflows," USEPA Report No. 11020FDC01/72
(NTIS No. PB 215 695), January, 1972.
TABLE 57. COMPARISON OF RAW COMBINED SEWER OVERFLOW QUALITY
Interval shorter than four days
COD BOD SS VSS
(mg/l) (mg/l) (mg/l) (mg/l)
Mean
a
N
149.6
54.6
31
39.6
22.1
23
149.8
73.4
31
81.5
38.8
32
Interval longer than four days
COD BOD SS VSS
(mg/l) (mg/l) (mg/l) (mg/l)
404.0
230.5
22
132.1
77.8
19
388.9
246.7
21
227.7
140.1
21
0* " standard deviation
N ™ number of samples
Source:
Rex Chalnbelt, Inc., "Screen/Flotation Treatment of Combined Sewer Overflows," USEPA Report No. 11020FDC01/72
(NTIS No. PB 21 5 695), January, 1972.
108
-------
As shown in Table 56, there is an obvious jump in potential strength
between the time intervals of four and five days for all the listed combined
sewer overflow characteristics. Table 57 compares data between time and
intervals of less than and over four days. According to these investigations,
four-day antecedent dry periods will produce a significant first-flush. (61)
Variables that influence the occurrence of the first-flush phenomenon
may include: the length of time between overflows, dry-weather flow variations,
the intensity of rainfall and runoff, area of the catchment, population.density,
sewer network configuration, land use, and the sewer system interceptor
capacity. (61)
In the Halifax, Nova Scotia study, the characteristics of the combined
wastewater flow were found to depend upon the relative proportions of sewage,
surface runoff, roof runoff, catch basin contents, and sewer solids included
in the flow. If surface runoff and roof runoff were the only significant
contributions to wet weather combined sewage flow, it could be expected that
as the rate of flow due to contribution of runoff increased, combined sewage
quality would approach the pollutant concentrations of surface runoff. As
storms continued, lower concentrations in surface runoff would result in
lower combined sewer concentrations. (55)
If the contributions from street and building sewers and catch basins are
significant, a first-flush of organic solids should result from a small flow
increase at the beginning of a runoff event. Thus, a higher concentration
would be experienced at the first occurrence of a given flow than would be
experienced with subsequent occurrences of a similar flow during the same
event. (55)
Each of these effects is depicted to some degree, as shown in Figure 34.
Subsequent solids peaks are associated with the contributions of surface
runoff, and are due to high relative runoff rates and their consequent removal
of pollutants within the drainage area.
A further analysis based on the ratio of volatile suspended solids to
total suspended solids showed that values of 0.75 were experienced during
flushing periods. This value was compared to a value of 0.8 for dry weather
flow, 0.3 for surface runoff and catch basin flows, and values of 0.75 to 0.8
for solids flushed from sewers at velocities from 0.46 to 1.5 m/sec (1.5 to
5 ft/sec). These comparisons suggest that in Halifax, the first-flush origi-
nates primarily from organic solids depositions within the sewer system, and
that other effects may often be masked by these contributions.
Other studies have noted the existence of a first-flush. A study of
surface runoff from an estate with separate sewers in Oxney, England, showed
BOD's up to 100 mg/1 and suspended solid concentrations up to 204 mg/1. It
was found that BOD's tended to increase with the length of dry weather prior
to a runoff event. After about 10 days, little change occurred. (62)
109
-------
1200
1300
1400
150O
1600
2000
Total and
Volatile
Suspended
Solids
JJj^p-^--
1000
1200
1300
AUGUST 4
1400 '1500
Time
'-1600
1700
1700
Total and 1000
Votatila
Suipandod
Solids
rng/l
1000
-=t±r
"•2
Rainfall
Intansity
1300
Total and
Volatile
Suspondod
Solids
mo/I
1000
0800
. .2
_,4 Rainfall
Intensity
-.6 in/hr
.8
1400
1400
1500
1600
'700
Rainfall
AUGUST 1O
150O 1600
Time
1700
1300
0900
10OO
1100
1200
AUGUST 21
HKQi
0800
0900
1000
110O
Time
1200
1800
1300
1300
The dashed line joins the time at which runoff started at the surface runoff samplers
to the time of collection of the first combined sewage sample.
Figure 34. First flush effects in combined sewage flows.
(Halifax, Nova Scotia)
Sourca: Waller, H. D., "Pollution Attributable to Surface Runoff and Overflows from Combinoc) Sowar Systems " Atlantic
Industrial Research Institute, Halifax, Nova Scotia, April, 1971.
110
-------
Stormwater samples from Seattle street gutters contained BOD's of about
10 mg/1; coliforms of up to 16,000 MPN's/100 ml; organic nitrogen of up to
9.0 mg/1; nitrate nitrogen up to 2.8 mg/1; and phosphorus up to 784 mg/1
soluble and to 1,400 mg/1 total, as phosphorus. The highest concentrations
usually were found when the rainfall was low and there was little detention
time in the system before sampling.
A study performed in Durham, North Carolina, on the characterization of
urban land runoff in separate sewer systems, generally corroborated the Nova
Scotia combined sewer experience. (64) Figure 35, portrays higher concentra-
tions of total suspended and volatile solids during the rising limb of the
hydrograph, with subsequent diminution of these concentrations until the next
peak on the hydrograph is approached. This tends to indicate the existence
of a first-flush effect and the later effects of higher subsequent rates of
runoff. One of the major findings of the study, however, indicated that the
significant independent variables found as a result of a regression analysis
of pollutant concentrations determined from 36 storm events were the discharge
rate and the time from the start of the storm event. The elapsed time from
the last storm was not found to be an important consideration in this analysis,
nor was the elapsed time from the last storm peak discharge of major signi-
ficance. These items must be considered in relation to the physical features
of Durham which differ from Halifax in such major items as percent pervious
area and type of sewer system.
These results tend to suggest little or no early influence on solids due
to solids accumulation within the basin itself. It seems likely therefore
that the major part of first-flushing effects are due to depositions and
erosion within the natural channel drainage collection system itself. In
the Halifax study, the few values for suspended solids concentrations in
surface runoff greater than 400 mg/1 that did occur coincided with higher
discharges later in the storm events studied. This showed that surfaces ac-
cumulations and surface runoff solids may not account for much of the first-
flush effect experienced in many drainage areas. (55)
It is likely, therefore, that a first-flush effect exists in combined and
even in separate storm systems, to some degree. The major source of this first
flush is the solids depositions within the collection system, as opposed to
the pollutants accumulated on the drainage basin itself. Contributions for
the latter source appear to be more important during subsequent discharge
peaks. In combined sewer collection systems, this is reflected by the rela-
tive diminution in volatile suspended solids concentration with time. It is
also likely that first-flush effects may be less apparent in large drainage
areas than in small ones. In large basins, first-flush contributions from
individual upstream sewer areas may be diluted by flows from downstream areas
where first-flushes have already been discharged. Thus, the apparent net
effect of total system first-flush contributions may be moderated due to
their relative distribution over time. (55).
Ill
-------
2200
2000
1800
1600
1400
1200
1000
800
600
400
200
Total Solids
Total Suspended Solids
Total Volatile Solids
Volatile Suspended Solids
500 r
400 -
300 -
200 -
100 -
T 1 1 —I 1 ! 1 1 T
1700 1800 1900 2000 2100 2200 2300 2400 0100
TIME (hrs)
Figure 35, Pollutant variation with flow and time for storm event no. 13.
Source: Colston, N.V., "Characteristics and Treatment of Urban Land Runoff," USBPA Report No. EPA-670/2-74-096
(NTIS No. PB 202865), December, 1974.
112
-------
STREET SURFACE POLLUTION POTENTIALS
Much of the pollutional load borne in urban stormwater has been assumed
to be largely due to the washing away of pollutants deposited on urban streets,
The street network of an urban area serves as a depository for the materials
that result from activities on and around city streets. Where urban streets
function as an extension of the runoff collection system, the assumption of
significant street pollutional contributions would appear to hold—particular-
ly for rainfall events that minimize the relative contributions from other
pollutant sources. Street surface accumulations, therefore, and the pollutant
potentials of their constituent fractions may represent an important aspect
of urban runoff discharge pollution.
Street Surface Accumulation Sources
Street surface accumulation sources are as diverse as the urban environ-
ments that produce them. Some of these may be characterized as: street
surfacing materials; grass clippings, street trees, and yard refuse; air
pollution emission sources; local soils; truck spillage; illicit dumping;
construction site wastes; adjacent vacant lots; the products of transportation
activities, including both vehicle-produced and vehicle-transported materials;
roof surfaces; parking lots and other impervious surfaces; and materials
applied for specific purposes, such as chemicals and abrasives for snow and
ice control purposes, or fertilizers, persticides and herbicides. A more
detailed evaluation of some of these varied sources appears in previous
portions of this section.
Major Street Surface Accumulation Components
The components of urban street surface accumulation have been roughly
classified on the basis of materials type as: rock, metal, paper, vegetation,
wood, glass, and dust and dirt. The distribution of street surface accumula-
tions into these categories are shown in Figure 36. At most of the sites
included in this figure, the largest and most stable component identified
was the dirt and dust fraction.
Another approach to the classification of street accumulation components
used in recent studies of street surface pollution categorized these materials
on the basis of particle size. Major components have been defined as the
litter, dust and dirt, and flush fractions. Litter is the largest fraction
and has been generally defined as the portion retained on a U.S. No. 6 sieve,
3.35 mm (0.013 in) mesh. (15) Dust and dirt is the fraction, passing the same
size screens. Dust and dirt has been called that part of urban street litter
"having the greatest pollution causing effect." (15) The flush fraction
represents that part of the pavement surface contaminants that can only be re-
moved by a flush of water after complete sweeping and vacuuming.
113
-------
LEGEND
Rock
Metal
Paper
Dirt
= Vegetation
nnBin 3 Wood
HUVVi = Glass
100
90
80.
70.
X
2 60.
UJ
ffl 50
H
U
cc 40.
30.
20 _
10-
34567
TEST AREA NUMBER
10 13 14 15 16 17
TEST AREA NUMBER
18
19
20
Figure 36. Average components of street litter, Chicago.
Source: American Public Works Association. "Water Pollution Aspects of Urban Runoff," USEPA Report
No. 11030DNS01/69 (NTIS No, PB 215 532), January, 1969.
-------
Street Accumulation Sampling Efforts
A number of studies have been performed to determine the pollutional po-
tentials of street surface accumulations. One of these studies was conducted
by the APWA on street accumulation samples collected in Chicago. (15) Another
study, performed by the URS Research Company, sampled various sites in a
number of cities across the country. (43) The latest study, by Shaheen, col-
lected samples in Washington, B.C. to evaluate the pollutional contributions
of transportation activities. (6) Still another survey was conducted in Omaha,
Nebraska during the summer of 1974 by the U.S. Army Corps of Engineers District.
(65) The detailed results of this latter study unfortunately, were not availa-
ble at the time of this writing. The data accumulated under this investigation
will be used for local sturm planning studies.
The sampling methods employed in each of these studies proved to be some-
what varied. This variation involved the size of the area sampled, sampling
technicques, the types of samples collected, the handling of samples for test-
ing purposes, and the laboratory tests performed. A summary of sampling
techniques are shown in Table 58. The variability of methods applied, is the
reason in part, for the degree of variation experienced in the comparison of
test results reported in a later portion of this section.
Sampling methods were tested in the case of the Shaheen study, (6) using
a simulated material made up of particles passing the U.S. No. 6 sieve
(3.35 mm (0.013 in)). Vacuum sweeping was found to satisfactorily recover
virtually all of the simulant on various types of surfaces with reputable
results.
Laboratory Analysis of Street Accumulation Samples
A number of laboratory analyses were performed on collected samples in
each of the major studies. A summary of the types of analyses performed are
shown in Table 59. As might be expected, one of the greatest problems en-
countered in performing laboratory analyses on collected dry solid samples
concerns their handling and processing to assure analytical results comparable
with the pollutional parameters and test procedures routinely employed for
water analyses.
The general practices employed for some of these solids analyses used
aqueous suspensions of mixed or homogenized dry samples. Homogenization in
itself may be assumed to change the physical characteristics of the street
surface materials in a way that may not occur through normal street activities
or runoff transport. It would appear to impose inaccuracies as a general
method except where it may be required by specific analytical testing procedures.
The aqueous suspensions in themselves may not represent the dissolved and col-
loidal pollutant fractions experienced in an actual runoff. In addition, they
may not represent actual runoff particulate concentrations that can exert an
influence on some of the analytical tests exercised—BOCg, COD, and other
constituents. It seems likely, therefore, that the measured values for some
street surface pollutants may be estimates of soluble and colloidal constituents
adulerated by the contributions of particulates resulting from physical sample
alterations due to processing procedures.
115
-------
TABLE 58. SAMPLING METHODS FOR MEASURING
STREET SURFACE ACCUMULATIONS
Sampling
Programs
Sample
Area
Land Uses
APWA"
Length :
Full block frontage
from building line
parallel to curb
Width: Gutter
Residential
Commercial
Industrial
URSb
Research
Co.
Length: 12-15 m
(40-50 ft)
parallel to curb
Width: 7.6m (25ft)i
to curb
74-93 m2 (800-1 ,000 ft2)
Residential
Commercial
Industrial
Biospherics0
Inc.
Length: 18-31 m
(60- 100 ft) or more
parallel to curb
Width: Gutter,
1.2 m (4 ft) 1
to curb
Isolated from
land use to the
degree possible to
reflect roadway
contribution
Some commercial
Omahad
District
U.S. Corps
of Engineers
Length: 1.5 m
(5 ft) parallel
to curb
Width: Gutter,
1.2m (4ft)lto
curb
Primarily
Residential
Sampling A. Hand Sweeping
Techniques B, Vacuum Sweeping
Sampling
Techniques
Most Often
Employed
Samples
Taken
Samples
Tested
Dry Samples
A. HandSweeping
B, Vacuum Sweeping
C. Flushing of hand
swept areas
D. Simulated rainfall
on unswept street
E. Simulated rainfall
on swept street
A on each site
C on occasion
Dry Samples
Liquid Samples
A. Hand Sweeping A. Hand Sweeping
B. Vacuum Sweeping
C. Flushing
A,B,C on
each site
Dry Samples
Liquid Samples
A on each
each site
Dry Samples
Dry Samples
passing the 0.3 cm
(0.18 in) mesh
pulverized with
subsequent screening
by U.S. No. 40 sieve
[0.00375cm (0.0015
Homogenized dry samples Dry litter samples Dry samples passing
and liquid samples
composited on the
basis of land use
in)]
retained on U.S.
No. 6 sieve
[0.03 cm
(0.012 in)]
Liquid samples
(flush fraction)
the U.S. No. 10
sieve
[0.02cm (0.008 in)]
Sourcei: 'American Public Work* Association. "Water Pollution Aspects of Urban Runoff," USEPA Report No
11030DNS01/69 !NTIS No. PB 215 532), January, 1969.
^Sartor, J.D.and G.B. Boyd, "Water Pollution Aspects of Street Surface Contaminants," USEPA Report No.
EPA-R2-72-081 {NTIS No. PB 214 408), November, 1962.
Shannon, D.B., "Contributions of Urban Roadway Usage to Water Pollution," USEPA Report No. EPA-600/
2-75-004 (NTIS No. PB 245 854), April, 1975.
Information on U.S. Corps of Engineers survey program was determined by telephone conversation with
Mr. Jack Rose, the project engineer for the Omaha District in March, 1975.
116
-------
Sampling
Program APWAa
TABLE 59. LABORATORY ANALYSES OF
STREET ACCUMULATION SAMPLES
URSb Omaha District11
Research Biosphericsc U. S. Army Corps
Company Inc. of Engineers
Samples Dry
Pollutant
Analyses Volume
Dry Weight
Water Sol. Fraction
Vol. Water Sol. Fraction
BODg
COD
N03
-
Kjeldahl N
So P04
-
-
-
..
,.
~
-
~
-
..
,.
-
-
-
Liquid-Dry
Composite
-
Dry Weight
(total solids
dry & liquid)
-
--
BODC
3
COD
N03
--
Kjeldahl N
~
Total PO4
-
-
-
-
~
-
Cadium
Nickel
Lead
Zinc
Copper
Chromium
Mercury
Litter (dry)
Dust-Dirt (dry)
Flush (liquid)
Dry Volume
Dry Weights
(total solids
liquid)
-
Vol. Solids
BODK
Q
COD
N03
N02
Kjeldahl N
Total PO4
Ortho-PO4
Chlorides
Asbestos
Rubber
Petroleum
n-paraffins
Cadium
Nickel
Lead
Zinc
Copper
Chromium
--
Dry
-
Dry Weight
--
--
BOD5
COD
-
--
Kjeldahl N
-
,,
-
-
-
--
-"
-
--
Nickel
Lead
Zinc
--
Chromium
Mercury
Chlorinated Hydro- Chlorinated Hydro-
carbons carbons
PCB's PCB's
Organic Phosphates
Cyanides
Hexavalent Chromium
Total Coliform
Fecal Enterococcus
Total Coliform
Fecal Coliform
Total Coliform
Total Coliform
Fecal Coliform
Fecal Streptococcus
* Note: Information on the Corps of Engineers analyses is incomplete as of this writing
Sources: aAmerican Public Works Association, "Water Pollution Aspects of Urban Runoff," USEPA Report No.
11O30DNS01/69 (NTIS No. PB 21 5 532)', January, 1969.
Sartor, J.D. and G.B. Boyd, "Water Pollution Aspects of Street Surface Contaminants," USEPA
Report No. EPA-R2-72-081 (NTIS No. PB 214 408), November, 1972.
cShaheen, D.B., "Contributions of Urban Roadway Usage to Water Pollution," USEPA Report No.
EPA-600/2-75-004 SNTIS No. PB 245 854), April, 1975.
Information on U.S. Corps of Engineers survey program was determined by telephone conversation
with Mr. Jack Rose, the project engineer for the Omaha District in March, 1976.
117
-------
Insofar as the effects of runoff transport mechanisms are not reflected
in these values, street surface pollutant measures provide one valid estimate
of urban pollution potentials, although the relationship of these potentials
to the actual pollution experienced in any runoff event may remain somewhat
unclear .
Street Surface Material Accumulation
The interaction of diverse urban environmental processes are generally
assumed to account for the accumulation of street surface materials . Pat-
terns of urban development, physical drainage area characteristics, local
climatology, construction practices, public works operations and maintenance,
transportation patterns, and human, social, economic and behavioral character-
istics represent some of these variables. Collectively, they prove too com-
plex to analyze readily. Thus, more generalized parameters have been used to
characterize street surface pollutants.
The most consistently used of these is gross land use. Street surface
materials are generally characterized by their accumulation and pollutional
composition in residential, commercial, and industrial areas. Other indepen-
dent variables that have been used for characterization purposes are: Climate,
landscaping, or land treatment adjacent to the paved streets, and street
surfacing materials. (43) Traffic volumes have also been used to characterize
the pollutional contributions associated with street traffic. (6)
The physical mechanisms by which street surface materials accumulate is
not wholly understood. Some theoretical generalizations have been suggested
by Sartor, et al. (43) and Shaheen et al. (6) These may be readily under-
stood from the standpoint of the following simplified conceptual mass balance:
where :
A-,-An reflects the net change in the storage of material accumula-
tions on the street surface where AQ is a base line accumula-
tion entrapped within the street surface and AI is the exist-
ing accumulation susceptible to ready removal.
D are airborne depositions including air pollutants, vegetative
a products, litter, trash, and other wind-blown wastes.
D are water-borne depositions of sediment from other pervious and
W impervious surfaces, and ground water constituents where sump
pumps may be used.
Dt are vehicle-produced materials such as exhaust emissions,
the products of vehicular wear, the products of street surface
abrasion and wear; and also include vehicle-transported materi-
als such as undercarriage deposits and spillage of transported
materials.
118
-------
R
are depositions from miscellaneous sources such as snow and ice
control chemicals and materials, litter, trash, dead animals,
animal wastes^and yard wastes,
are material removals by the wind erosion processes.
are removals due to runoff in all forms—rainfall, snow melt,
irrigation surpluses, and other water sources.
are transportation-related material removals due to traffic
generated blowoffs or through the pickup and transport of
materials on individual vehicles.
are intentional removals effected by public works operations
and programs such as street cleaning and flushing, solid waste
collection and disposal; and street maintenance activities.
The foregoing suggests the major mechanisms involved in the accumulation of
street surface materials. It has been hypothesized that the accumulation of
street materials would take the form of the curve represented in Figure 37.
ta
z
5
3
0
TIME
Figure 37. Accumulation of contaminants — typical case
(natural build-up with periodic sweeping and intermittent rainfall)
Source: Sartor, J.D., and Q.B. Boyd, "Water Pollution Aspects of Street Surface Contaminants,"
USEPA Report No. EPA-R2-72-081 (NTIS No. PB 214408), November, 1972.
This approach considers the sum of the contributions of all deposition pro-
cesses at a constant rate. The net effects of the various removal processes,
with the exception of runoff and street cleaning, result in an accumulation
function that was essentially linear in its early time steps and subsequently
asymptotic to a maximum accumulation value as the time interval became long,
and constant rate depositions were balanced by removal processes.
A genera] expression for this theoretical approach, (6) assuming a
clear1 street at the outset is:
L = C (1 - e-Kt),
K
where:
(15)
119
-------
Lfc is the street accumulation at time t, Ib/curb-mi
C is a constant average deposition rate, Ib/curb-mi/d
K is an overall average removal constant
t is time step, in days.
Another similar approach to the same problem provides a general recursive
expression in the form: (6)
Lt = (Lt_! + C) (1- X) (16)
where L, C and t are as defined above and X is the removal constant.
This expression simply says that the street loading at tiue t is given
by the loading at time t-1, plus what is deposited, minus what is removed
during the interval [t-1, t]. It can be shown inductively that this
recursive expression is a polynomial of degree t in X , i.e., -
t
Lt = C £ (1- X )i (16a)
A graphical comparison of both expressions for various overall removal
constants, K and X » is shown in Figure 38. Attempts to verify this theo-
retical approach with data collection on street surface accumulations and
antecedent times, based on actual street cleaning and rainfall intervals,
have proved inconclusive to date.
Support for the concept of maximum levels of street surface accumulations
and non-linear overall accumulation rates, however, was developed in the Bio-
spherics study in Washington, D.C. (6) Amounts of street surface materials
were found to level off after three to four days of accumulation. Average .
ratios of single to multiple— day measurements indicated that overall accumula-
tion rates were non-linear.
In the Washington study (6) two processes were suggested as influencing
removal rates — the mechanical break-up of deposited particles to smaller sizes,
and the removal of particles by vehicular traffic through blow-off or physical
pick-up and transport.
The simplified mass balance previously described suggests some of the
difficulties involved in defining the complex processes of street surface
material accumulations. An insufficiency of real field data limits a more
complete analysis of these processes.
120
-------
K = 0.5
O
CO
g
LU
Q
u.
O
I-
Ul
O
cc
111
Q.
»
O
U
u
180 _
160 _
140 _
120
100
K = 0.6
I
8 9 10
TIME, DAYS
11 12 13
Figure 38. Theoretical street accumulations at various time intervals and overall
removal constants, k & X.
121
-------
Street Surface Accumulation Measurements
The majority of street surface accumulation measurements are reported as
average daily accumulations, as opposed to rate-defined accumulations as pre-
viously discussed. These data are based on actual street measurements and the
units most often reported are kg/curb-km/day (Ib/curb-mi/day).
Mean values from the Chicago study (15) for both total street refuse and
dust and dirt are reported in Table 60.
TABLE 60. AMOUNT OF TOTAL REFUSE AND DUST AND DIRT BY LAND USE
Amount of Total Litter Amount of Dust and Dirt1
By Land Use By Land Use
Land Use kg/curb-km/day Ib/curb-mi/day kg/curb-km/day Ib/curb-mi/day
Single Family
Residential
Multiple Family
Residential
Commercial
Industrial
30
52
80
113
105.6
184.8
285.1
401.3
10
34
49
68
37.0
121.4
174.2
242.9
• Whore total litter was all material swept up and Dust and Dirt was fraction passing 0.31 cm (0,125 in) screen.
Soyrco: American Public Works Association, "Water Pollution Aspects of Urban Runoff," USEPA Report No.
11030DNS01/69 (NTIS No. PB 215 532), January, 1969.
Similar information is reported in the results of a later multi-city
sampling project by the URS Research Company. (43) A summary of these
results appears in Table 61.
TABLE 61. MEAN VALUES OF
STREET SOLIDS ACCUMULATION
BY LAND USE
Accumulations of Street Solids
Land Use
Residential
Commercial
Industrial
kg/curb-km/day
166
51
395
Ib/curb-mi/day
590
180
1,400
Source: Sartor, J.D., and G.B. Boyd, "Water Pollution Aspects
of Street Surface Contaminants," USEPA Report No.
EPA-R2-72-081 (NTIS No. PB 214 408), November,
1972.
122
-------
The street accumulation measurements enforced in Washington, D.C. (6)
generally do not provide data on measurement relationships to land use. These
observations were made to evaluate traffic-related pollutional contributions.
Sampling sites were selected to minimize influence of all but traffic on
street surface contaminants. Two commercial sites were sampled, however,
where land-use influences were considered likely. A tabluation of mean
accumulation values for these sites is given in Table 62. These values have
been reported in a three-component format, indicating the mean amounts of
street litter, dust and dirt, and flush fractions as defined in the study. (67)
TABLE 62. MEAN STREET SURFACE ACCUMULATIONS FOR COMMERCIAL LOCATIONS
(WASHINGTON, D.C.)
Litter Fraction1 Dust and Dirt2 Flush Fraction3
Site Ib/curb-mi/day kg/curb-km/day Ib/curb-mi/day kg/curb-km/day Ib/curb-mi/day kg/curb-km/day
CAMP Station
Street Samples
Mean
Range
Shopping Center
Parking Lot
Samples
Mean
Range
Overal
Mean
Range
53
19.5-99.2
7.4
2.1-13.9
27.6
2.1-99.2
15
5-28
2
1-4
11
1-28
174.7
55.2-365.3
60.2
35.3-108.8
134.7
35.3-365.3
49
16-103
17
10-31
38
10-103
9.3
4-18.8
—
9.3
4-18.8
3
1-5
—
—
3
1-5
Litter Fraction: that portion of the participates retained by a U.S.A. No. 6 sieve, greater than 3.35 mm in diameter.
o
Dust and Dirt: participates smaller than 3.35 mm in diameter (U.S.A. No 6 sieve).
Flush Fraction: components of the dust and dirt fraction which were not picked up at high efficiencies by the sweeping and vacuuming
techniques.
Source: Shaheen, D.B.,"Contributions of Urban Roadway Usage to Water Pollution," USEPA Report No. EPA-600/2-75-004 (NTIS
No. PB 245 854), April, 1975.
123
-------
Samples collected by the U.S. Corps of Engineers in Omaha, Nebraska, (65)
by hand-sweeping methods resulted in composite street solids accumulation
values for older residential areas of 29 kg/curb-km/day (103 Ib/curb-mi/day).
Of this amount, the dust and dirt fraction was 21 kg kg/curb-km/day (75 Ib/
curb-mi/day). In newer residential areas, the total debris was 6 kg/curb-
km/day (14 Ib/curb-mi-day). The major focus of this sampling effort was
directed to residential land uses since most of the commercial and industrial
streets in the area were uncurbed.
Street surface measurement information supplemented by mass discharge
data developed from runoff discharge information uncovered by the existing
literature, was compiled and statistically analyzed by the URS Research
Company. (5) The result of this analysis provided the street solids ac-
cumulation values indicated in Table 63.
TABLE 63. STREET SOLIDS ACCUMULATION
LOADING RESULTING FROM THE ANALYSIS
OF EXISTING DATA
Street Surface Loadings
Land Use
Residential
Commericial
Light Industry
Heavy Industry
Open Space
All Uses
Ib/curb-mi/day
149
74
389
203
12
156
kg/curb-km/day
42
21
110
57
3
44
Source: Amy G., "Water Quality Management Planning for Urban
Runoff, USEPA Report No. EPA-440/9-75-004 (NTIS No.
PB 241 689), December, 1974.
A comparative summary of reported values for dust and dirt or its closest
equivalent is shown in Table 64. The values indicated in this table are
averages of field measurements performed using somewhat different methods and
subject to varying definitions of similar characteristics. Some of these
variations were previously mentioned. Ready comparisons of these data should
124
-------
TABLE 64. COMPARATIVE SUMMARY OF REPORTED VALUES
FOR STREET SURFACE SOLID ACCUMULATION LOADINGS
BY LAND USE
{Dust and Dirt Fractions)
ReportedValues in kg/curb-km/day
(Values in Ib/curb-mi/day)
Land Use
Residential
Single Family
Multi-Family
Commercial
Industrial
Light
Heavy
Open Space
All Uses
APWA1
— —
10
(37)
34
(121)
49
(174)
68
(243)
—
—
—
—
URS2
Research
Company
1972
166
(590)
—
__
51
(180)
395
(1,400)
—
« —
—
—
Omaha4
District
Biospherics3 U.S. Corps
Inc. of Engineers
4-21
(13-75)
— —
—
49
(175)
— —
— —
— —
— —
49
URS5
Research
Company
1974
42
(149)
21
(74)
110
(389)
57
(203)
3
(12)
44
(175)
(156)
Source: American Public Works Association, "Water Pollution Aspects of Urban Runoff,"
USEPA Report No. 11030DNSO1/69 (NTIS No. PB 215 532), January, 1969.
Sartor, J.D., and G.B. Boyd, "Water Pollution Aspects of Street Surface
Contaminants," USEPA Report No. EPA-R2-72-081 SNTIS No. PB 214 408),
November, 1972.
Shaheen, D.G., "Contributions of Urban Roadway Usage to Water Pollution,"
USEPA Report No. EPA-6OO/2-75-004 (NTIS No. PB 245 854), April, 1975.
4
Telephone conversation; Omaha District Corps of Engineers, 1975.
Amy, G., "Water Quality Management Planning for Urban Runoff," USEPA
Report No. EPA-440/9-75-004 (NTIS No. PB 241 689), December, 1974.
be somewhat suspect on this basis. However, all the street measurement data
show a relative compatibility as to magnitude, with the possible exception
of the URS Research Company data, (5) This is two or more times other re-
ported values, with the exception of the commerical land use, and is con-
sistently higher in all cases due to variations in measurement practices.
•125
-------
Street Surface Material Deposition Characteristics
The distribution of surface materials on paved streets varies due to
street geometry, traffic patterns, vehicular parking practices, and type of
pavement. The results of a sampling program conducted in a number of cities
are presented in Table 65.
TABLE 65. AVERAGE PERCENT
TOT ALSO LIDS LOAD
ACROSS STREET WIDTH
Cumulative
Distance From Percentage of
Curb Face Total Loading
0.5 ft (0.15m) . 78
1.0 ft (0.3m) 88
3.5 ft (1.1m) 97
8.0 ft (2.4 m) 98
to street centerline 100
Source: Sartor, J.D., and G.B. Boyd, "Water Pollution Aspects
of Street Surface Contaminants," USEPA Report No.
EPA-R2-72-081 (NTIS No. PB 214 408), November,
1972.
The table shows that the majority of street surface solids will accumu-
late within 15 cm (6 in) of the curb face and virtually all accumulations
may be accounted for within 1.1 m (3.2 ft). Little accumulation occurs with-
in the traveled lanes, although greases and other automotive fluids that may
bond to the street surface, may be found along the centerlines of traffic
and parking lanes. Vehicular movement tends to blow particulates out of the
traffic lanes, the cross-sectional slope of the street downward to the curb
enhances particulate movement to the curb by gravity, and the curb face usual-
ly provides trapped area for some of the moving solids. Parked vehicles also
add to the accumulation through the entrapment of moving material, and be-
cause they interfere with the planned removal of street accumulation by
street cleaning.
It has also been found that street surface materials are not uniformly
accumulated longitudinally along streets. This is due to variations in street
geometry. Intersections, bus stops, driveways, deceleration lanes, turning
lanes, etc. were all found to produce major variations in the distribution of
street surface accumulations. Intersections were found to be one-third as
heavy in accumulations than the other street portion and driveways were
found to be 30 percent less than curbed street sections. (5) Assuming that
these estimates are valid, a theoretical block distribution of 0.5 blocks/ha
(128 blocks/mi2) each block being 200 m by 100 m (660 ft by 330 ft) from
right-of-way centerline, would result in only seven to thirteen percent over-
all reduction in accumulations (assuming fully curbed sections in a single-
family residential area with off street parking) due to variations in geometry
alone. For commercial areas the reduction would be somewhat less.
The relative effects of curb height on measured accumulations of street
surface materials were studied in Washington, B.C. The results are shown in
Figure 39.
126
-------
E
^f
•e
I
300
(85)
1 200
| (56)
,0
CA
£
z*
o 100
< (28)
D
D
O
10
25
20
50
30
75
40
100
50 in
125 cm
BARRIER HEIGHT
Figure 39. Accumulation of litter and dust and dirt with barrier height.
Source: Shaheen, D.G., "Contributions of Urban Roadway Usage to Water Pollution,"
USEPA Report No. EPA-600/2-75-004 (NTIS No. PB 245 854), April, 1975.
The variation in average total accumulation values for six sampling lo-
cations compared to the height of the curb or barrier are shown along with a
regression line for the reported data. Both litter and dust and dirt fractions
generally increase with increasing curb height. Thus, shifting patterns due
to traffic-generated or natural winds would be inhibited by curb height with
greater amounts of materials captured on streets as a function of increasing
curb height. The implications of this particle capture phenomenon on street
development policies is immediately apparent. A strategy directed to the
removal or entrapment of street surface particulates might require a revision
of street standards. This would be the case whether removal and entrapment
was by street cleaning and materials disposal or through the elimination of
curbing and the use of strategically located plantings or vegetation.
An analysis of available sampling data collected in Washington (6) in-
dicated the effects of pavement surface type and changes in the relative dis-
tribution of street accumulation components over time. The data was grouped
on the basis of sampling time'intervals and pavement surface type. It was
assumed that initial or first samples taken at the beginning of the sampling
periods, represent valid estimates of street surface accumulation characteris-
tics. The composition of collected street surface accumulation samples at
various collection frequencies is shown in Table 66. This information shows
that a disparity among sample components exists for each pavement surface
type for one and three-day frequency samples.
127
-------
TABLE 66. PERCENTAGE OF TOTAL STREET SOLIDS ACCUMULATION
FOR DEFINED SAMPLE COMPONENTS FOR ALL SITES
AT VARIOUS COLLECTION FREQUENCIES
Sample Components (%of Total Accumulation)
Sample Litter Fraction Dust-Dirt Fraction Flush Fraction
Collection Concrete Asphalt Concrete Asphalt Concrete Asphalt
Freauenev. davs Pavement Pavement Pavement Pavement Pavement Pavement
1
3
3.6
Many days
5.1
7.5
--
43.0
32.0
--
31.4
45.0
92.2
91.4
--
55.3
67.6
-
60.9
52.1
1.8
1.1
..
1.7
0.4
--
7.7
2.9
Sourca: Shaheen D.G., "Contributions of Urban Roadway Usage to Water Pollution," USEPA Report
No. EPA-600/2-75-004 (NTIS No. PB 245854), April, 1975.
Similarity exists in the distribution of components among the many day (or
initial) samples. The time-related changes in the composition of accumulations
are similar for each type of pavement. In each case, the relative proportion
of dust and dirt diminishes with time due to the weathering of accumulated ma-
terials and their removal by runoff and other climatic effects. Precipitation
data were unavailable to make any estimates of specific wash-off event charac-
teristics.
Comparisons of litter and dust and dirt components on concrete and
asphalt surfaces also showed some notable variation. Although the sum,of
percentages of litter and dust and dirt fractions were similar for each pave-
ment, litter material was found to be a greater proportion of the total ac-
cumulation for asphalt surfaces while dust and dirt was greater for concrete
pavement. Pavement surface type and the definition of the litter and dust
and dirt fractions are probably responsible for much of this difference.
Paving surface materials, depending on their type, age, wear and weathering
characteristics, could contribute to either litter or dust and dirt when
classification is based on the U.S. No. 6 sieve, 3.35 mm (0.012 in). In
view of the general characteristics of these paving materials, asphaltic
concrete wear or weathering products would probably contribute more to the
litter fraction, while Portland cement concrete would produce, more dust and
dirt sized materials. An annual pavement thickness reduction of 0.32 cm
(0.125 in) on a 10.9 m (36 ft) wide roadway could produce from 56 to 110 kg/
curb-km/day (200 to 400 Ib/curb-mi/day) if everything was captured on the
roadway, depending on the surfacing material. On the assumption that all
surficial materials on concrete pavements will be added to the dust and
dirt sized fraction (
-------
It has been noted that debris accumulations on asphaltlc surfaces have
been found to be about 80 percent heavier than on all concrete streets, while
mixed concrete and asphalt surfaces are about 65 percent heavier. (43) This
general observiation was verified by other sampling programs, (64)
Thus, the distribution and magnitude of deposited street surface materials
are subject to a number of considerations. Street geometry, curb height, and
pavement type are merely a few. Climatic effects, topography, and prevalent
soil types among other factors, also contribute to street accumulation depo-
sition characteristics, and they may explain some of the variance experienced
in field sampling these materials.
Physical Characteristics of Street Surface Contaminants
The particle size distribution of street surface accumulations is one of
their most important characteristics. The association of relative pollutant
concentrations with particle size bears not only on the movement of pollutants
to receiving waters but also on some of the methods that may be employed to
control these pollutants. Physical wastewater treatment processes are also
dependent upon particle size distributions as are street cleaning operations.
Particle size distributions have been studied in each of the major street
sampling activities to date. The Chicago study analyzed large particle sizes
(15), the results of which are shown in Table 67.
TABLE 67. SIEVE ANALYSES OF
SELECTED STREET SOLIDS SAMPLES
AVERAGE AND RANGE (CHICAGO, ILLINOIS)
Particle Size Commercial Industrial
(microns) Site Site
>2,000 5.8% 3.4%
2.5-12.4%
1,190-2,000 7.8% 7.0%
5.2-12.4%
840-1,190 5.2% 6.4%
4.1- 6.9%
590-840 6.6% 12.8%
5.0- 8.4%
< 590 74.6% 70.4%
58.8-82,5%
Source: American Public Works Association, "Water Pollu-
tion Aspects of Urban Runoff," US EPA Report
No. 11030DNS01/69 (NTIS No. PB 215 532),
January, 1969.
The greatest percentage by weight of the materials are below 590 microns
(0.023 in). Insofar as coarse sand may be described as from 420 to 2000
microns (0.0165 to 0.0786 in) in size, the majority of the street materials
samples appear comparable in size to find sand 74 to 2000 microns (0.0029
to 0.0786 in), silt 5 to 74 microns (0.002 to 0.0029 in) and clay soils, less
than 5 microns (0.002 in) in size.
A more detailed analysis of street surface material samples was performed
in connection with a later study. The results of the analysis are shown in
Table 68.
129
-------
TABLE 68. PARTICLE SIZE DISTRIBUTION
OF STREET SOLIDS
SELECTED CITY COMPOSITES - PERCENT
Size
Ranges
Microns
> 4,800
2,000-4,800
840-2,000
246-840
104-246
43-104
30-43
14-30
4-14
<4
Milwaukee
12,0
12.1
40.8
20.4
5.5
1.3
4.2
2.0
1.2
0.5
Bucvrus
—
10.1
7.3
20.9
15.5
20.3
13.3
7.9
4.7
-
Baltimore
17.4
4,6
6.0
22.3
20.3
11,5
10.1
4.4
2,6
0.9
Atlanta
_
14.8
6.6
30.9
29.5
10.1
5.1
1.8
0.9
0.3
Tulsa
-.
37.1
9.4
16.7
17.1
12.0
3.7
3.0
0.9
0.1
Source: Sartor, J.D., ond Q.B. Boyd, "Water Pollution Aspects of
Street Surface Contaminants," USEPA Report No.
EPA-R2-72-081 (NTiS No. PB 214 408), November,
1972.
Similar analyses performed on the samples collected in Washington, B.C.,
are shown in Table 69.
TABLE 69. PARTICLE SIZE ANALYSIS IN PERCENT FOR STREET SOLID SAMPLES
COLLECTED FROM SPECIFIC SITES
(WASHINGTON, D.C.)
Site
3,350-1,700
Particle Size Ranges, microns
1,700-850 850-420 420-250 250-150
150-75
75-45
Interstate Highway
Unused Interstate
5.4
4.1-10.6
4.6
8.0'.
5.2-14.0
6.2'
16.2
11-21.5
6.6
22.2
16.9-26.6
11.8
19.4
16.2-20.9
16.1
17.8'
11.2-23.0
24.5
714
2-15.2
15.7
3.6
0.9-6.0
14.5
Highway
Arterial Roadway
Arterial Roadway
Urban Highway
Shopping Center
Commercial Street
11.8
5.9-31.5
3.2
1.7-4.6
8.7
5.3-11.2
1.8
0.3-2.8
5.5
4.1-9.0
13.2
8.5-17.
7.1
3,6-11.
9.6
7.7-10.
6.3
4.0-9.0
8.0
5.7-9.8
9
8
8
22.4
16.2-29.1
19.4
16.1-22.4
14.4
13.4-15.7
19.7
6.6-25.6
18.6
17.6-20.4
23.8
15.1-29,
25.2
20.2-31,
14.3
13.2-16
25.4
20.4-31,
23.0
19.9-27.
.6
.5
.5
,6
14.8
9-17.5
19,1
15.4-23
12.3
10.4-14
15.4
11.8-18
16.3
.6
.1
.9
14.8-17.7
9.5
6.4-13.6
17.6
10.1-22.
17.2
13.5-19.
16.4
10.3-20.
17.0
12.4-19.
8
2
1
9
3.0
1.2-8.7
7.6
2.6-10
13.4
11.2-15.6
10.8
6.3-18.2
10.6
2.8-16.3
1.6
0.2-3.6
0.6
0.3-1.5
10.0
8.3-12.8
4.3'
0.6-6.8
1.0
0.3-1.7
Sou re*:
Shahoon, D.Q., "Contributions of Urban Roadway Usage to Water Pollution," USEPA Report
No. EPA-600/2-7S-004 (NTiS No. PB 245 854!, April, 1975.
130
-------
On the assumption that there is compatibility between the analytical
methods employed, a comparison of findings from all three studies is pre-
sented in Table 70.
TABLE 70. COMPARISON OF STREET SOLID
PARTICLE SIZE DISTRIBUTION
ANALYSIS RESULTS
Comparable Ranges of Particle Sizes, microns
Location
Chicago 'al
Commercial
Industrial
Milwaukee(b)
Bucyrus"3'
Baltimore(b>
At!anta
2.000-850
13.0%
13.4%
40.8*
7.3*
6.0 *
6.6*
9.4*
850-250
_
..
20.4
20.9
22.3
30.9
16.7
250-45
-
_
6.8
35.8
31.8
39,6
29.1
<45
--
—
7.9
25.9
18.0
8.1
7.7
Washington^0'
Interstate Highway --- 38.4 44.6 3.6
Unused Interstate
Highway -- 18.4 56.3 14.5
Arterial Roadway - 46.1 27.3 1.6
Arterial Roadway - 44.6 44.3 0.6
Urban Highway -- 28.7 42.9 10.0
Shopping Center - 45.1 42.6 4.3
Commercial Street - 41.6 43.9 1.0
"Actual particle size ranges reported are 84O-2,QGQjLi,
840-246/U. 246-43jU and less than or equal to 43/Lt
Sources: (a) American Public Works Association, "Water Pollution
Aspects of Urban Runoff," USEPA Report No.
1103ODNSO1/69 (NTIS No. PB 215 532), January,
1969.
(b)Sartor, J.D.,and G.B. Boyd, "Water Pollution Aspects
of Street Surface Contaminants," USEPA Report No.
EPA-R2-72-081 (NTIS No. PB 214 408), November,
1972.
(c) Shaheen, D.G., "Contributions of Urban Roadway
Usage to Water Pollution," USEPA Report No,
EPA-600/2-75-OO4 (NTIS No. PB 245 854), April,
1975.
The overall comparisons indicate that some similarities exist among the
sample sites analyzed. In most cases, the major fraction of street surface
accumulations is from 850 to 45 microns (0.033 to 0.0018 in). This would
be equivalent to a material range of coarse sand to medium silt. In individual
cases, the coarser or finer fractions may be relatively greater. This is most
likely due, however, to the make-up of local soils. (43) A prevalence of
local soils composed of silts or clays could result in greater small-particle
fractions while local gravels or coarse sands could make large-particle
fractions more significant.
131
-------
An analysis of the specific gravity of selected samples was performed in
connection with the Chicago study. The resulting ranges of specific gravity
for the fractions of individual samples tested are shown in Table 71.
TABLE 71. SPECIFIC GRAVITY
ANALYSIS OF VARIOUS FRACTIONS
OF SELECTED STREET
DUST AND DIRT SAMPLES
(CHICAGO, ILLINOIS)
Specific Gravity
Land Use Range of Test Findings
Commercial 2.588-3.027
Commercial 2.295-2.578
Commercial 2.197-2.484
Industrial 2.488-2.652
Source: American Public Works Association; "Water
Pollution Aspects of Urban Runoff," USEPA
Report No. 11030DNS01/69 (NTIS No. PB 215
532), January, 1969.
Most local soils in the Chicago area may be characterized as having a
specific gravity of from 2.6 to 2.7. Thus, most of the values shown indicate
the presence of non-mineral constituents including organics. The highest
specific gravity noted was probably due to the metallic contributions added
from an overhead rapid transit railway at the sampling site.
Pollutional Potentials of Street Surface Contaminants
The pollutional potentials of street surface accumulations have been
found dependent on the particle size distribution of these materials. The dis-
tribution of solids has been previously considered. A summary of the findings
associated with field observations made in a number of cities is given in
Table 72.
TABLE 72. FRACTION OF POLLUTANT ASSOCIATED WITH
EACH PARTICLE SIZE RANGE
(% By Weight)
Particle Size (micron)
> 2.000 840-2,000 246-840104-24643-104 <43
Total Solids
Volatile Solids
BOD5
COD
Kjeldahl Nitrogen
Nitrates
Phosphates
24.4
11,0
7,4
2.4
9.9
8.6
0
7.6
17.4
20.1
4.5
11.6
6.5
0.9
24.6
12.0
15.7
13.0
20.0
7.9
6.9
27.8
16.1
15.2
12.4
20.2
16.7
6.4
9.7
17.9
17,3
45,0
19,6
28.4
29.6
5.9
25.6
24,3
22.7
18.7
31.9
56.2
Source: Sartor, J.D.; and G.B, Boyd, "Water Pollution Aspects of Street Surface
Contaminants," USEPA Report No. EPA-R2-72-081 (NTIS No. PB 214
408), November, 1972.
132
-------
The table provides a summary tabulation of solids content, oxygen de-
mand, and some of the nutrients that may exist in runoff flow. Interestingly,
the fraction of the total solids of 246 microns (0.0097 in) or less, while
less than 50 percent of the total accumulation by weight, accounts for the
majority of all pollutants reported. More than a quarter of the volatile
solids, nitrates, and phosphates are associated with the fraction of 43 microns
(9.0017 in) or less. Thus, the management of small particles may assume a
relatively high degree of importance in street runoff quality control.
A more detailed analysis of the organic constituents contained in com-
posited samples was performed to identify tannins and lignins having their
source in vegetation; carbohydrates from food wastes, methylene blue active
substances from anionic detergents, organic acids, and grease and oil. The
results of this analysis are shown in Table 73.
TABLE 73. ORGANIC ANALYSIS OF SELECTED
STREET SOLID SAMPLES
% of Total Assumed Loading
Assumed Loading Associated With Particle Size
Constituent Ib/curb-mi kg/curb-km > 246 microns <246 microns
Tannins and Lignins
Carbohydrates
Organic Acids
MB AS
Grease and Oil
0.17
1.06
—
0.07
18.0
0.05
0.30
—
0.02
5.07
44.3
61.5
—
64.9
52.6
55.7
38.5
—
35.1
47.4
Source: Pitt, R.,and G. Amy, "Toxic Materials Analysis of Street Surface Contaminants," USEPA
Report No. EPA-R2-73-283 (NTIS No. PB 224 677/AS), August, 1973.
The major amounts of carbohydrates, methylene blue active substances, and
grease and oil are associated with the small particle fraction below 246
microns (0.0097 in). Vegetative debris, as represented by the analysis of
tannins and lignins are apparently associated with the fraction above 246
microns.
An analysis of the pollutants associated with various particle size
ranges was conducted on samples collected in Washington, B.C. The results
are shown in Table 74. The values reported are based on the dust and dirt
fraction rather than on a total solids fraction made up of a composite of
litter, dust and dirt, and flush materials. The findings generally corro-
borate those reported in the previous table (based on composite solids).
Those pollutant percentages associated with the 250 micron (0.0098 in) or less
size account for a significant amount of the total pollutant load. Visual
comparison of the data suggests that the pollutant percentages are similar
for all size ranges, with the exception of the largest and smallest fractions.
133
-------
TABLE 74. PERCENTAGE OF
POLLUTANT POTENTIAL ASSOCIATED WITH
VARIOUS RANGES OF STREET SOLIDS
PARTICLE SIZE
{WASHINGTON, D.C.)
Pollutant Ranges of Particle Size, microns
Dust and Dirt 3,350-850 850-420 420-250 250-75
Commercial Street
Shopping Center
Isolated Roadways
Volatile Solids
Commercial Street
Shopping Center
Isolated Roadways
BOD
Commercial Street
Shopping Center
Isolated Roadways
COD
Commercial Street
Shopping Center
Isolated Roadways
Total PO4-P
Commercial Street
Shopping Center
Isolated Roadways
Commercial Street
Shopping Center
Isolated Roadways
NO2-IM
Commercial Street
Shopping Center
Isolated Roadways
Total Kjcldahl N
Commercial Street
Shopping Center
18.8
8.7
13.2
25.1
9.4
16.4
20,8
11.3
11.9
21.2
6.4
10.7
11.9
4.2
12.2
17.1
14.4
9.3
52.8
5.3
15.3
31.5
8.6
20.4
22.8
16,2
17.0
17.3
10.2
19.0
16.7
14.5
16.0
13.7
10.6
14.5
12.5
14.0
14.1
13.5
12.2
11.2
13.9
15.8
28.8
29.6
27.6
23.0
21.1
17.1
10.4
11.7
24.5
21.0
15.0
18.2
13.1
12.7
18.3
22.4
17.2
18.7
12.2
16.1
0.0
17.6
11.7
18.5
17.6
30.1
28.7
35.2
34.0
29.9
36.0
28.6
26.0
33.7
37.0
33.8
39.6
47.5
28.7
37.6
40.9
32.0
35.4
16.9
17.3
31.2
18.9
25,8
<75
3.1
16.8
14.3
6.8
33.0
25.7
7.1
25.0
24.9
7.6
33.0
26.4
7.8
32.2
19.0
9.2
27.9
27.0
19.1
45.9
26.0
2.4
18.4
Isolated Roadways 20.2 19.5 16.5 26.9 16.9
Source: Shaheen, D.G., "Contributions of Urban Roadway Usage to Water
Pollution," USEPA Report No. EPA-600/2-75-004 (NTIS No. PB
245 854J, April, 1975.
134
-------
A similar analysis of other pollutants by size range was also conducted
on the Washington, B.C. samples. These appear in Table 75.
TABLE 75. PERCENTAGES OF POLLUTANT
POTENTIALS ASSOCIATED WITH VARIOUS
PARTICLE SIZES OF STREET SOLIDS
(WASHINGTON, D.C.)
(microns)
Pollutant 3,380-850 850-420 420-250 2BO-75
Grease
Petroleum
n-Paraffin
Asbestos
Rubber
Chlorides
Fecal Streptococcus
11.6
10,8
10.2
13.0
3.0
13.5
5.4
10.3
9.1
9.0
15.5
5.4
17.0
1.2
12.5
12.5
11.6
20.5
11.3
16.6
2.6
40.1
39.9
40.7
39.6
37.8
33.6
63.6
25.5
27.7
28.5
11.4
42.5
21.6
27.2
Source: Shaheen, D.G., "Contributions of Urban Roadway Usage to Water
Pollution," USEPA Report No. EPA-600/2-75-004 (NTIS No. PB
245 854), April, 1975.
The majority of all of these pollutants is associated with the smaller
particle size ranges, fhese findings generally agree with those previously
indicated for grease and oil.
A summary of the precentages of elemental heavy metals in various
particle size ranges is presented in Tables 76 and 77. The distribution of
pollutants to particle size ranges in both tables shows fair agreement for
the same metals. The table indicates that cadmium is most frequently as-
sociated with the fraction of 246 microns (0.0097 in) or less, while iron,
manganese, and nickel are more related to the fraction above 246 microns
(0.0097 in).
TABLE 76. PERCENT OF HEAVY METALS IN
VARIOUS STREET SOLIDS PARTICLE
SIZE RANGES
(microns)
Average Of Four
Cities: . Tulsa,
Baltimore, San
Jose II. Seattle
Zinc
Copper
Lead
Iron
Cadmium
Chromium
Manganese
Nickel
Strontium
<104
20
26
14
11
36
20
16
23
34
104
to
246
26
33
28
21
52
24
20
17
12
246
to
495
21
15
35
21
12
17
20
31
15
>495
33
26
23
47
0
39
44
29
39
Source: Pitt, R., and Q. Amy, "Toxic Materials Analysis of Street
Surface Contaminants," USEPA Report No. EPA-R2-73-283
(NTIS No. PB 224 677/AS), August, 1973.
135
-------
TABLE 77. PERCENTAGES OF ELEMENTAL
HEAVY METAL POLLUTANTS ASSOCIATED
WITH VARIOUS STREET SOLIDS PARTICLE
SIZE RANGES
(WASHINGTON, D.G.)
Ranges of Particle Size, microns
Pollutant 3.380-8BO 850-420 420-250 250-75
-------
TABLE 79. THE PERCENTAGE OF TOTAL POLLUTANT LOADS ASSOCIATED WITH
THE MAJOR FRACTIONS OF STREET ACCUMULATIONS AND PAVEMENT TYPES
Sample
Collection Total Volatile
Frequency Sample Accumulation BOD5 ' COD Solids
Days Fraction
1
3
3.6
Many
Days
Litter
Dust/Dirt-Flush
Litter
Dust/Dirt-Flush
Litter
Dust/Dirt-Flush
Litter
Dust/Dirt-Flush
32
68
-
--
31.4
68.6
45.0
55.0
5.1
94.9
7.5
92.5
-
--
43
57
61.3
38.7
--
--
63.5
36.5
70.7
29.3
27.7
72.3
29.7
70.3
-
-
79.9
20.1
59.1
40.9
—
-
89.9
10.1
88.3
11.7
12.9
87.1
27.8
72.2
..
--
85.7
14.3
88
12
„
--
75.5
24.5
87.3
12.7
33.2
66.8
9.4
90.6
__
-
58.5
41.5
Source: Shaheen, D.G., "Contributions of Urban Roadway Usage to Water Pollution," USEPA Report No. EPA-600/2-75-004 (NTIS
No. PB 245 854), April, 1975.
of the contaminant loading related to each. The pattern of each is somewhat
different for each pavement type. The asphalt litter or approximately 32
percent of the total accumulation, accounts for 61.3 percent of the total
BODc while only the concrete litter, or 5.1 percent of the total accumulation
produces 27.7 percent of the total BOD^. A fair degree of consistency in
the proportions of pollutants attributable to each litter fraction over time
for unweathered samples occurs for totalaccumulations, and BOD^ and volatile
solids on asphaltic surfaces and for total accumulations, and BOD^ on Portland
cement surfaces. Among weathered samples, the distribution of fractions and
pollutants appear relatively the same for most pavement type comparisons.
A reasonable degree of linear association appears to exist for the per-
centage of the total BOD,- and COD, compared to street accumulation fraction
percentages, when data from both street surfacing types are commingled. Al-
though the data are limited and, therefore, suspect, this tends to suggest that
some consistency may be assumed in the distribution of pollutants compared to
mass accumulations for some pollutants.
The foregoing indicates that the effect of rainfall and the removal of the
dust and dirt and flush sized accumulations by runoff can be identified through
net changes in their composition over time. This is evidenced by the greater
relative influence due to the litter fraction with weathering of the accumula-
tion regardless of pavement surfacing. A higher relative proportion of the dust
and dirt and flush particles and pollutants will probably be removed from con-
crete than asphalt surfaces. This would be due to the large relative propor-
tion of street materials in these size ranges on concrete surfaces.
A tabulation of average dust and dirt accumulations and related pol-
lutant concentrations is shown in Table 80. The table shows mean values of
137
-------
TABLE 80. AVERAGE DAILY DUST AND DIRT ACCUMULATION AND RELATED
POLLUTANT CONCENTRATIONS FOR SELECT FIELD OBSERVATIONS
Pollutant
Land Use Categories
Dust and Dirt
Accumulation
Ib/curb-mi/day
kg/curb-km/diy
Chicago'1'
Washington {z'
Multi-City'31
.
All Data
BOD mg/kg
COD mg/kg
Total N-N
(mg/kg)
Kfeldahi N
(mg/kgl
N03
(mg/kg)
N02-N
(mg/kg)
Total PO4
(mg/kg)
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs.
Mean
Range
No. of Obs
Single Family
Residential
35(10)
19-96(5-27)
60
,.
-•
-
182(51)
3-950(1-268)
14
62(17)
3-950(1-268)
74
5,260
1,720-9,430
59
39,250
18,300-72,800
59
460
325-525
59
-
-
..
Multiple Family
Residential
109(31)
62-153(17-43)
93
157(44)
8-770(2-217)
8
113(32)
8-770(2-217)
101
3.370
2.030-6320
93
41,970
24,600-61,300
93
550
356-961
93
,.
Commercial
181(51)
71-326(80-151)
126
134(38)
35-365(10-103)
12
45(13)
3-260(1-73)
10
116(47)
3-365(1-103)
158
7,190
1,280-14,540
102
61,730
24,800-498,410
102
420
323-480
80
640
230-1,790
22
24
10-35
21
0
0
15
170
90-340
21
Industrial
325(92)
284-536(80-151)
55
288(81)
4-1,500(1-423)
12
319(90!
4-1,500(1-423)
67
2,920
2.820-2,950
56
25,080
23,000-31,800
38
430
410-431
38
All Data
158(44)
19-536(5-15)
334
134(38)
35-365(10-103)
22
175(49)
3-1,500(1-423)
44
159(451
3-1,500(1-423)
400
5,030
1,288-14,540
292
46,120
18,300-498,410
292
480
323-480
270
640
230-1,790
22
24
10-35
21
15
0
15
170
90-340
21
138
-------
TABLE 80 (cont'd)
Pollutant"
Land Use Categories
P04-P
(mg/kg)
Chlorides
(mg/kg)
Asbestos
fibers/lb
(fibers/kg!
Ag
(mg/kg)
As
(mg/kg)
Ba
(mg/kg I
CD
(mg/kg)
Cr
(mg/kg)
Cu
(mg/kg)
Fe
(mg/kg)
Hg
(mg/kg)
Mn
(mg/kg)
Ni
(mg/kg)
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No, of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Gbs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Single Family
Residential
49
20-109
59
-
Multiple Family
Residential Commercial
58
20-73
93
-
-
60
0-142
101
220
100-370
22
57,2x1 (^(^exIO6)
Industrial
26
14-30
38
-
-
0-172.5x108(0-380x106) -
-
„
3.3
0-8.8
14
200
1 1 1 -325
14
91
33-150
14
21.280
11,000-48,000
14
450
250-700
14
38
0-120
14
--
..
2.7
0.3-6.0
8
180
75-325
8
73
34-170
8
18,500
11,000-25,000
8
-
340
230-450
8
18
0-80
8
16
200
0-600
3
0
0
3
38
0-80
8
2.9
0-9.3
22
140
10-430
30
95
25-810
30
21,580
5,000-44,000
10
0.02
0-0.1
6
380
160-540
10
94
6-170
30
-
-
-
-•
3.6
0.3-11.0
13
240
159-335
13
87
32-170
13
22,540
14,000-43,000
13
430
240-620
13
44
1-120
13
All Data
53
0-142
291
220
100-370
22
57,2x106(126x106)
0-172.5x106(0-380x106)
16
200
0-600
. 3
0
0
3
38
0-80
8
3.1
0-11.0
57
180
10-430
65
90
25-810
65
21,220
5,000-48,000
45
0.02
0-0.1
6
410
160-700
45
62
1-170
65
139
-------
TABLE 80 (cont'd)
Pollutant
Land Use Categories
Single Family Multiple Family
Residential Residential Commercial Industrial
All Data
Pb
Imf/kj}
Sb
(mfl/kjl
So
{ms/kg!
Sn
(mg/kg)
Sr
(mf/kg)
Zn
fmfl/kg}
Fecal Strep
HaJgrm
Fecjl Coli
No./gram
Total Coli
No^gram
Mean 1,570
Range 220-5,700
No. of Obs 14
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean
Range
No. of Obs
Mean 32
Range 5-110
No. of Obs 14
Mean 310
Range 110-810
No. of Obs 14
Geo. Mean
Range
No. of Obs
Geo. Mean 82,500
Range 26-130,000
No. of Obs 65
Geo. Mean 891,000
Range 25,000-3,000,000
No. of Obs 65
1,980
470-3,700
8
..
18
12-24
8
280
210-490
8
38,800
1,500-1,000,000
96
1,900,000
2,330
0-7,600
29
54
50-60
3
0
0
3
17
0-50
3
17
7-38
10
690
90-3,040
30
370
44-2,420
17
36,900
140-970,000
84
1,000,000
80,000-5,600,000 18,000-3,500,000
97
85
1,590
260-3,500
13
13
0-24
13
280
140-450
13
30.700
67-530,000
42
419.000
27,000-2.600,000
43
1,970
0-7,600
64
54
50-60
3
0
0
3
17
0-50
3
21
0-110
45
470
90-3,040
65
370
44-2,420
17
94,700
26-1,000,000
287
1,070,000
18,000-5,600,000
290
Source: 'American Public Works Association, "Water Pollution Aspects of Urban Runoff," USEPA Report No.
U030DNSOI/69 (NTIS No. PB 215 532), January, 1969.
2Shaheen, D.G., "Contributions of Urban Roadway Usage to Water Pollution," USEPA Report No,
EPA-600/2-7S-004 (NTIS No. PB 245 8S4), April, 1975.
3Sartor, J.D., and G. B. Boyd, "Water Pollution of Street Surface Contaminants," USEPA Report No.
EPA-R2-081 (NTIS No. PB 214 408), November, 1972.
''Amy, G., "Water Quality Management Planning for Urban Runoff," USEPA
Report No. EPA-440/9-7S-004, (NTIS No. PB 241 689), December, 1974.
Note: Data for this table has had the flush fraction and some URS Data edited out - this data represents sweeping values
only. Tables 60 ond 64 reflect the flush fraction and thus differ from Table 80.
daily values of all reported samples collected by mechanical and pneumatic
methods, but not flushing. All the data included in these values were defined
in terms of a specific sampling location. Although the preponderance of the
reported data included in this tabulation was taken on asphaltic pavements (in
many cases with a concrete gutter)» a few samples were collected on concrete
pavement. In these few cases, dust and dirt accumulations were uniformly
lower in magnitude than those measured on asphalt. A more detailed description
of street measurements is given in Appendix B, Data Management for Street
Surface Solids Accumulation Samples.
140
-------
Although the table does not reflect accumulations measured by flush
sampling methods, some detailed investigations were conducted in the Washington
study (6) of the significance of flush samples. As it is normally used, flush-
ing with limited amounts of water is accomplished subsequent to mechanical and
pneumatic sampling. Flush sample data, therefore, indicate some of the parti-
culate and soluble accumulations that are not readily removed from a pavement
surface by high efficiency mechanical and pneumatic cleaning. Rainfall simula-
tion studies have shown that approximately a 90 percent capture of settleable
materials took about one-half hour of simulated rainfall at a rate of 2 cm/hr
(0.8 in/hr) on new asphalt and concrete. Dissolved, colloidal and suspended
materials required about an hour at the same simulated rainfall rate. (43)
Thus, it is not clear that flushing with limited water quantities, even though
under pressure, is wholly representative of residual materials to be found on
street pavements. Flushing is important, however, as an indication of some
pollutants that do occur in high percentages in this fraction. A relative
distribution of the percentages of pollutants associated with the flush com-
ponent of dust and dirt plus flush samples, is shown in Table 81.
TABLE 81. PERCENTAGE OF POLLUTANTS FOUND IN
DUST AND DIRT AND FLUSH SAMPLES ATTRIBUTABLE
TO THE FLUSH FRACTION
Pollutant
Accumulation
(dry weight)
Volatile Solids
BOD
COD
Total PO4-P
P04-P
NO3-N
NO2-N
Kjeldahl N
Chlorides
Asbestos
Lead
Chromium
Copper
Nickel
Zinc
F. Strep
F. Co!i
Number Of
Observations
82
82
82
82
82
82
82
82
82
82
68
10
10
10
10
10
82
82
Average Percentage
In Flush Fraction
7
20
36
16
15
43
69
97
33
43
13
4
17
5
5
2
44
76
Range Of Flush
Fraction Percentages *
5.2-8.8
17.1-22.9
31.1-40.9
13.3-18.7
11.7-18.3
33.7-52.3
63.7-74.3
95.4-98.6
27.9-38.1
35.7-50.3
5.4-20.6
2.5-5.5
5.7-28.3
2.0-8.0
3.5-6.5
1.2-2.8
35.3-52.7
67.1-84.9
* Ranges inferred at 95% confidence interval
Source: Shaheen, D.G., "Contributions of Urban Roadway Usage to Water Pollution/
USEPA Report No. EPA600/2-75-004 (NTIS No. PB 245 854), April, 1975.
141
-------
The table clearly shows that, although the flush sample contributes
relatively little to the street accumulation by weight, it does influence
BCtt>5, phosphate and nitrate, Kjeldahl nitrogen, chlorides, and bacteriologi-
cal indicators. In addition, it accounts for virtually all of the nitrates
measured. This suggests that significant amounts of these pollutants are
associated with street accumulations that are incapable of capture with pre-
sent mechanicial and pneumatic street cleaning methods.
Application of Street Surface Contaminant Data
The previous discussions have related the results of field measurements
of street surface contaminants from a number of urban sites across the
country. The values related provide an indication of the magnitude of po-
tential pollutants to be expected from a variety of urban land uses. They
also form the basis for analytical techniques and models employed to esti-
mate urban runoff pollutional contributions; evaluate alternative control
and abatement methods; project the influence of land use changes on runoff
quality; and perform other analytical functions.
As noted in Appendix B, available data on street surface contaminants are
relatively limited, and subject to some variation due to sampling and ana-
lytical procedures. Thus, this body of data does not provide universal
answers to pollutional loadings from street surface contaminants. Verfifica-
tion of the results obtained from using this data in applicable models is
therefore desirable. Verification involves the collection of runoff discharge
data from representative urban drainage basins. These data preferably should
include precipitation information, runoff quantities over time, and an array
of related discrete samples taken in a manner representative of average condi-
tions of flow quality. Verification in this case takes the form of comparisons
of measured and estimated results for the same runoff event within the defined
drainage basin.
Another approach to the application of measurements of runoff discharge
was employed by the University of Florida in the STOKM and SWMM modelling as
reported in Volume II, Section ?.
Measuredand Calibrated Results
This calibration effort was limited to street accumulation values only.
Non-point runoff estimating methods such as the Universal Soil Loss Equation
or estimations of contributions from other sources such as roof runoff, catch
basins and first flush effects, were not employed for calibration purposes.
In spite of this fact, the potentials of model calibration as a means to more
effectively reflect local variations in input due to climate, region, local
development, soils, and other factors are clearly of value. Adjustments to
the given street surface accumulation values cited within this section with
locally obtained data on pollutant concentrations or mass emissions can result
in more accurate analytical tools for the evaluation of urban runoff as well
as new insights into the problems of prevention, abatement, and control.
142
-------
STREET SURFACE ACCUMULATION REMOVAL MECHANISMS
Street surface accumulations are removed from streets by a number of
methods—both planned and unplanned. Planned removal mechanisms involve the
various street cleaning methods that may be used in any urban area. Unplan-
ned removals include those accomplished by wind erosion processes; surface
runoff including rainfall, snow melt and irrigation surpluses; and, transpor-
tation-related removals due to traffic-generated blow-off, or by the pick-up
and transport of materials on or attached to individual vehicles. The most
significant of these removal processes are those attributable to street clean-
ing and surface runoff.
Street Cleaning Practice
Some of the pollutants that are accumulated on urban streets are removed
by street cleaning operations. The amount of material removed by street clean-
ing will vary according to local practice in terms of the frequency of clean-
ing, cleaning methods, and the effectiveness of these methods. Thus, street
cleaning activities affect the amounts of materials removed and, more im-
portantly, the effect street cleaning has on the accumulation of pollutants on
streets.
Street cleaning operations usually employ abrasive (mechanical) or abrasive
and pneumatic machinery and, in some cases, water flushing equipment. Abrasive
street cleaning equipment employs brooms to impart sufficient energy to street
accumulation particles for their collection. Two types of brooms are generally
used—the gutter broom to remove material from the gutter area and make it
accessible to the main or pick-up broom and the pick-up broom which moves the
material to a conveyor and collection bin. Brooms may be made up ,pf a number
of materials—natural fiber, steel filaments, and synthetic fibers.
In tests performed in Pomona, California using a simulant material [NO.
16 Sand, 0.12 cm (0.049 in)] , on a 0.9 m by 91 m (3 ft by 300 ft) strip, a
four-wheel abrasive sweeper operated with pick-up efficiencies of from 80
to 98 percent at broom pattern widths of 17.8 and 22.9 cm (7 and 9 in). A
three-wheeled abrasive sweeper produced similar results. Vacuum sweepers
resulted in pick-up efficiencies in the range of 97 to 99.5 percent. (15)
This range of efficiency is higher than that experienced in actual practice
because the conditions of the tests were ideal for equipment performance.
A study of sweeper performance in connection with radiological decontamina-
tion described abrasive sweeper effectiveness by the following genral ex-
ression: (69)
M = M* + (MQ - M*)e~KE (17)
where:
M = the mass remaining after sweeping (g/ft^)
M = the initial mass before sweeping (g/ft )
M* = an irreducible mass remaining after any amount of sweeping
(and dependent upon the type of sweeper, the surface, and
particle size)
143
-------
e = 2.718
K = a dlmensionless empirical constant dependent upon the sweeper
characteristics
E = the amount of sweeping effort involved (equipment min/
1000 ft2 swept)
A comparison of removal effectiveness between abrasive and vacuum sweeping
was made as part of the same study. (69) The results are shown in Table 82.
TABLE 82. COMPARISON OF REMOVAL EFFECTIVENESS
FOR ABRASIVE AND VACUUM SWEEPING
Machine
Type
Abrasive
Vacuum
Abrasive
Vacuum
Relative
Effort (E)
min/1.000ft2
2.17
2.88
4.32
5.83
20 g/ft2
177-300/j
(%)
92.5
95.0
94.5
98.5
100 g/ft2
71-177/j
(%)
58.0
94.5
—
—
600 g/ft2
74-1 77 n
(%)
46.0
89.5
62.6
91.4
NOTE: Tests conducted on asphaltic concrete. Results are for 1 pass in 2nd gear and
1 pass in 3rd gear.
g/ft2 = Initial mass level
fj. = Particle size range of simulant
% = Removal effectiveness = (Mo-M*)/Mo x 100
s.g. = 2.65
Source: Sartor, J.D. and G.B. Boyd, "Water Pollution Aspects of Street Surface
Contaminants," USEPA Report No. EPA-R2-72-08I (NTIS No. PB 214 408),
November, 1972.
This shows pick-up effectiveness for various particle size ranges deter-
mined as a result of strip tests. Thus, removal effectiveness would be some-
what higher than might be experienced under actual cleaning conditions. In
any case, vacuum cleaning apparently operates at a higher removal effectiveness
than abrasive cleaning for smaller particle size ranges.
The results of street tests to determine the effectiveness of street
cleaning in a number of cities in terms of percent removal are shown in
Table 83.
144
-------
TABLE 83. SUMMARY OF STREET CLEANING EFFECTIVENESS TESTS1
A.
1
2
3
4
5
6
City
Milwaukee
Baltimore
Scottsdale
Atlanta
Tulsa
Phoenix
Test
No.
Mi-3
Ba-7
SC-1
At-9
Tu-6
PII-2
Pick-Up
Street Equipment
Type Condition Type Condition
Concrete
Asphaltic
Asphaltic
Asphaltic
Concrete
Asphaltic
Good
Fair
Good
Good
Good
Poor
Wayne 94.5
Wayne 945
Wayne 985
Elgin Pelican
Elgin Pelican
Mobile TE-3
Fair
New
Worn (50%)
Fair
Worn (50%)
Fair
Broom
Speed
(rpm)
2,000
2,000
—
n.a.
n.a.
1,700
Strike
cm in.
20.3 8
14.0 5%
12.7 5
15.2 6
1.0.2 4
12.7 5
Vehicle Speed
Gear km/hr mph
3rd
2nd
2nd
2nd
2nd
2nd
8.8
6.4
8.8
5.5
6.6
8.8
5.5
4.0
5.5
3.4
4.1
5.5
3.
1
2
3
4
5
6
Test
No.
Mi-3
Ba-7
SC-1
At-9
Tu-6
PII-2
Initial Loading
g/m2 lb/1,000 ft2
18.2 3.72
53.1 10.86
36.2 7.40
27.8 5.68
64.5 13.24
108.0 22.09
Residual Loading
g/m2 lb/1,000 ft2
9.6
47.0
16.0
18.8
41.9
40.7
1.96
9.62
3.28
3.85
8.57
8.32
Removal
Effectiveness
47
11
56
32
35
62
1.
n.a.
All units, abrasive type
= not available
Source: Sartor, J.D., and G.B. Boyd, "Water Pollution Aspects of Street Surface
Contaminants," USEPA Report No. EPA-R2-72-081 (NTIS No. PB 214 408),
November, 1972.
These results show a range of overall removal effectiveness for abrasive
cleaning equipment of from 11 to 62 percent. Overall average removal effective-
ness was found to be 50 percent. The effectiveness of removal varies with
particle size. The concentration of pollutants in street solids also varies
with particle size. The effectiveness of abrasive street sweeping equipment
decreases with a decrease in particle size, as shown in Table 84, the concentra-
tion of pollutants in street solids increases with a decrease in particle size.
It is noted, for example, that the particles of less than 43 microns represent
only 5.9 percent of the total solids while they are 24.3 percent of the total
BOD.
145
-------
TABLE 84. ABRASIVE SWEEPER EFFICIENCY
WITH RESPECT TO PARTICLE SIZE
Sweeper
Particle Size Efficiency
(Microns) *%}
> 2,000 79
840 - 2,000 66
246 - 840 60
104- 246 48
43- 104 20
< 43 15
Overall 50
Source Sifter, J.D., and G.B. Boyd, "Water Pollution Aspects of Street Surface Contaminants," USEPA
Report No. GPA-R2-72-081 (NTIS No. PB 214 408), November, 1972.
From the foregoing it is apparent that removal effectiveness should
be determined in terms of equipment type and its related efficiency in
removing particles of various sizes. As is apparent, the relative interval
between street cleaning may have a strong bearing on the amount of potential
pollution available to runoff on urban streets. An indication of current
practice as to street cleaning intervals is shown in Table 85. As might be
predicted, the shortest cleaning intervals are used in central business
areas. The data shown do not reflect the methods of cleaning employed.
TABLE 85. STREET CLEANING INTERVALS (DAYS)
FOR VARIOUS POPULATION RANGES
AND LAND USES
Population
Range
10,000
to
50,000
50,000
to
100,000
100,000
to
250,000
250,000
to
1,000,000
AN
Data
Days Between Sweeping Events
Residential Commercial Industrial
Low Medium High Central Local
Density Density Density Business Business
Mean 64.8
a 15.2
n 47
Mean 60.7
a 9.4
n 32
Mean 55.3
0 12.1
n 25
Mean 41.5
a 13.5
n 19
Mean 58.9
a 13,7
51.0
12.2
49
49.8
7.5
32
50.0
9.9
23
44.1
13.5
18
48.1
11.4
36.0
11.6
37
37.6
5.4
31
47.5
11.0
23
39.0
6.4
18
38.1 .
9.0
5.5
1.3
50
9.7
17.6
33
5.8
1.6
26
7.4
2.7
16
6.8
8.9
11.6
3.8
48
15.2
17.2
30
9.4
3.3
22
10.3
4.1
18
11.5
9.3
32.0
12.6
29
36.5
19.5
25
19.5
3.9
18
23.0
15.5
18
29.3
16.0
n 127 126 113 128 121 93
Note: O is defined as the correlation coefficient
N is defined as number of responses
Sourc*: 1973.APWA Survev of Street Cleaning, Catch Basin Cleaning and Snow and Ice Removal Practice.
146
-------
An alternative or supplementary approach to street cleaning Involves the
use of flushing with water. In some jurisdictions flushing is employed to
supplement other street cleaning activities. An investigation of street
flushing performed in connection with radiological decontamination using a
synthetic test material—industrially processed clay loam, produced some
results of interest. Simulant materials applied at levels of approximately
0.1, 0.4 and 1.1 kg/m2 (22, 72.7 and 220 lb/1,000 ft2)(70), were removed by
manual hose flushing and mechanized flushing. Manual flushing operations were
performed with a hose at a nozzle pressure of from 5.27 to 5.62 kg/cm (75 to
80 psi) with a 1.5 cm (0.6 in) nozzle orifice on a standard 3.7 cm (1.5 in)
fire hose. Mechanized flushing was accomplished with two different equipment
units. One was a conventional 11,340 1 (3,000 gal) flushing unit with three
nozzles, operating at a nozzle pressure of 3.87 kg/cm (55 psi), a nozzle
orifice of 0.16 cm (0.06 in) and a spray direction of 60° to the line of
travel. The other unit employed a 2.6 m (8.5 ft) long spreader of a 5 cm
(2 in) diameter of 5.98 kg/cm2 (85 psi) an angle of application with the pave-
ment of 30° and a spray direction of 60° to the line of travel.
The findings of various field measurements were characterized in the form:
„ 1/3
M = M* + (Mo - M*) e~J ° (18)
In which M* = M*0(l + e'^)
1/3
where M - M*Q(1 + e" aMo) + [MQ - M*o C1 + e" *Mo)le"3K°E
9
M = Residual street loading after flushing, g/ft
M* = Residual street loading remaining after an infinite
flushing effort, g/ft2
MO = Initial street loading, g/ft2
M*0 = A constant limiting upper value for M* for each pave-
ment and cleaning method, g/ft2
a = Loading spreading coefficient dependent on pavement
surface, cleaning method, loading particle size and
density
K = Efficiency constant
f
E ~ Flushing effort, equip. min/103ft'
147
-------
Values for some of the factors defined in the previous equation are
shown in Table 86.
TABLE 86. REPRESENTATIVE VALUES FOR
VARIOUS FACTORS IN DETERMINING EFFICIENCY
OF STREET FLUSHING
Asphalt Pavement
Concrete Pavement
Flushing Method
3-nozzle flusher
14 flat jet nozzles
firehose
d
0.0081
0.0081
0.0081
K
o
1.05
1.05
0.42
M
2.
2.
2.
#
o
0
0
0
d
0.0064
0.0064
0.0064
Ko
1.05
1.05
0.42
M
1.
1.
1.
*
o
0
0
0
Source: Owen, W.L., etal., "Stoneman II Test of Reclamation Performance:
Volume II, Performance Characteristics of Wet Decontamination
Procedures," USNRDL-TR-325, U.S. Naval Radiological Defense
Laboratory, San Francisco, California, July, I960.
Some of the results of this study are shown in Figures 40, 41 and 42.
3 7
5=
•8
E, flushing effort
equip, min/103 ft2
10 20 30 40 50 6O 70 80 9O 100
Mo, Initial street loading (g/ft2)
Source: Owen, W.L., et el., "Stoneman II Test of Reclamation Performance:
'Volume II. Performance Characterisitcs of Wet Decontamination
Procedures," USNRDL-TR-325 (NTIS No. AP 248 069/LK), U.S.
Naval Radiological Defense Laboratory, San Francisco, California,
July, 1960.
Figure 40. Residual mass as a function of initial mass loading
for various levels of flushing effort on concrete surfaces,
mechanized flushing.
148
-------
s 6
01
,E 5
"1
4* 4
_ 3
(8
3
13
'vt «
w 2
e
E, flushing effort
equip, min/103 ft
I
I
i
I
10
20
30
40
SO
60
70
80
90 100
MQ, Initial Street Loading (g/ft2)
Figure 41. Residual mass as a function of initial mass loading for various
levels of flushing effort on asphalt surfaces, mechanized flushing.
E, flushing effort
equip, min/10 ft2
10
20
100
M0, Initial Street Loading (g/ft2 )
Source:
Figure 42. Residual mass as a function of initial mass loading for various
levels of flushing effort on asphalt and concrete surfaces, firehose
flushing.
Owen, W.L., et al., "Stoneman II Test of Reclamation Performance: Volume II,
Performance Characteristics of Wet Decontamination Procedures," USNRDL-TR-32S
(NTIS No. AP 248 069/LK), U.S, Naval Radiological Defense Laboratory, San
Francisco, California, July, 1960.
149
-------
The relative effectiveness of the three flushing methods is shown in
Figure 43. This comparison was based on an initial street loading of 1.08
kg/ra2 (0.22 lb/ft2).
FIREHOSING - ASPHALTIC OR PORTLAND CEMENT CONCRETE
MOTORIZED FLUSHING - ASPHALTIC CONCRETE~
MOTORIZED FLUSHING - PORTLAND CEMENT CONCRETE
I I I I I I
I I I
I I I
I I I I I
20
30 40 5O
E,eq. min/103ft2
60
70
Source: Owan, W.L., ot al., "Stoneman II Test of Reclamation Performance: Volume II,
Porformnnca Chnroctorlstlcs of Wet Decontamination Procedures," USNRDL-TR-325
(NTIS No. AP 248 069/LK), U.S. Naval Radiological Defense Laboratory, San
Francisco, California, July, 1960.
Figure 43. Comparative effectiveness of motorized flushing and
firehosing on pavement.
Uncontrolled Removal
Uncontrolled removals are accomplished through wind erosion processes,
transportation-related removals due to traffic generated blow-off or the
pick—up and transport of accumulations on and by means of vehicles and through
removals due to runoff in all forms. Of these, surface runoff constitutes
the most significant removal process in terms of receiving water pollution.
An indication of general wind erosion processes for lands adjacent to
roadways was discussed in the previous section on airborne contributions to
urban runoff pollution. In addition, vehicular emissions for unpaved roads
was also discussed. Studies in Washington State (72) produced traffic dust
emission estimates shown in Table 87. This information indicates particu-
late emission factors in Ib per vehicle-mi for a number of road types at
specific vehicular speeds.
150
-------
TABLE 87. TRAFFIC DUST EMISSION FACTORS
Speed
km/hr
16.7
33,3
50.0
33.3
mph
10
20
30
20
Type of Road
And
Test Site
Weight/Vehicle Distance
Total Below
Particulates
kg/veh-km
Ib/veh-tni
10 Microns
kg/veh-km
Ib/veh-mi
Below
2 Microns
kg/veh-km
Ib/veh-mi
Percent
Below
10 Microns
Number
of
Tests
Gravel Road, Duwamish Valley
10th Ave. S. from
Same
Same
Dusty Pave Road •
S. 92nd to S. 96th
- No Curbs
0.95
1.91
.6:05
3.5
7.0
22,2
0.16
0.54
2,53
0.58
1.9
9.0
0.028
0.067
0,22
0.10
0,24
0.77
16.7
27.4
40.4
1
17
1
S. Kenyon-7th Ave. S. — S. Chicago
8th Ave. S. Duwamish Valley 0.23 0.83 0.047 0.17
33.3 20 Paved Road With Curbs - Flushed Weekly
Swept Biweekly* — 6th Ave. S. Between
S. Alaska and S. Lander 0.04 0.14 0.001B O.OOE
33.3 20 Gravel Road East of Redmond
N.E. 40th Between 260th Ave. N.E,
and 272nd Ave. N,E. 1.99 7.3 0,56 2.0
0.006
0.022
20.3
3.82 1
27.1
* The standard deviation of the average grains per actual cubic foot (g/acf) of 17 samples at mph on 10th Ave, S, is 0.010. In 95% of the cases the true average would He between
0.133 g/acf+0,010 x 1.96 which would give a 6.0 Ib/veh-mi to 8.1 Ib/veh-mi emission factor.
Source:
Roberts, John Warren, "The Measurements, Cost and Control of Air Pollution From Unpovod Roads and Parking Lots in Seattle's Duwamish Valley," A thesis submitted
In partial fulfillment of the requirements for the degree of Master of Science In Engineering, University of Washington, 1973.
Every 14 days (per phone call 4/25/75 John Roberts)
-------
Another study resulted in estimates of the surface deposition fraction
that is resuspended with each passing vehicle. (71) This study employed a
phosphorescent tracer (specific gravity = 4.1) with a mass median diameter
of approximately 5 mm (0.2 in). From this study the following can be said:
Resuspension factor
airborne concentration/rar
surface concentration/m^
Resuspension factors of the trace material were found to increase with
the square of vehicle speed and ranged from 10" to 10
"^
The resuspension
due vehicles travelling in an adjacent lane to the trace material was ap-
proximately one order of magnitude less.
The variation in resuspended particulates with vehicular speed is shown
in Figure 44.
O
cc
UJ
I
S
o
cc
u.
Q
tu
Q
10 ~2 -
10
-3
Ul U
d>
1s
CC Q.
<
Q.
a.
O
Z
O
O
<
cc
u.
10
-s
11 1
Car Driven-Through
Tracer
Truck Driven-Through
Trace
Car Driven-By —
Tracer
1
1.6
10 100 mph
16 160 km/hr
VEHICLE SPEED
Sou re o: Sahmel, G.A., "Particle Resuspension from an Asphalt Road Caused by Car and Truck
Traffic, Atmospheric Environment, ParBamon Press, Vol. 7 (291-309), Great Britain,
1973,
Figure 44. Particle resuspension rates from an asphalt road
caused by vehicle passage.
152
-------
The effects of particle weathering were found to decrease resuspension
rapidly with time. Weathering effects are demonstrated in Figure 45.
Car Speed
6 50 mph (80 km/hr)
SOmph (48 km/hr)
.1.1.1.1
I
10 20 30 40 50 60 70 80
WEATHERING TIME. DAYS
Source: Sehmel, G.A., "Particle Resuspension from an Asphalt Road Caused by Car and Truck
Traffic," Atmospheric Environment, Pergarnon Press, Vol. 7 (291-309J, Great Britain,
1973.
Figure 45. Particle resuspension rates from an asphalt road as a function of weathering
(car driven through tracer).
Estimates of traffic related accumulation removal rates, as defined by
the general equation first discussed in an earlier section, were developed
in the Washington, D.C. study. (6)
L = C (1 - e-KT)
K
(19)
where:
L = roadway pollutant loading, Ib/mi
C = per axle deposition rate, Ib/axle/mi
e = 2.718
K = fractional traffic related removal rate /axle
T = total traffic in axles
The resulting estimated values for K were from 1 x 10"^ to 3 x 10~ per
axle. These values, however, were computed on the basis of dust and dirt load-
ing that was attributable to traffic contributions only.
As to the problem of vehicular pick-up and transport of street accumula-
tions, the study in Washington State (72) reported that material deposits on a
passenger car were found to be as much as 36.4 kg (80 Ib) after the vehicle was
153
-------
driven on country roads. This was supported by another direct measurement of
materials collected on a passenger car driven through the farmlands of Illinois,
that showed approximately 27.3 kg (60 Ib) of transported materials. (6)
The most significant uncontrolled street surface accumulation removal mecha-
nism is surface runoff. The wash-off of street surface accumulations has been
characterized as:
where:
Po(l-eKrt)
(20)
PQ is the initial street accumulation loading in Ib
P is the street accumulation remaining at time interval t,
after removal at runoff rate, r
r is the average runoff in in./hr
K is a constant dependent on street surface characteristics
t is the time interval
e - 2.718
Studies of the wash— off of contaminants on streets, using a rainfall simula-
tor device, showed that the above mathematical expression accurately describes
this phenomenon. (43) Some of the results of these studies are presented in
Figure 46. Values of the constant K were found to be dependent on street sur-
face characteristics. Unfortunately, representative values for K for various
street surface types were not reported. Although values for K are critical, '
general practice to date has been to assume a 90 percent removal of the initial
street accumulation with a uniform runoff of 1.2 cm/hr (0.5 in/hr) .
I I I I I I
104- 246 fl
44-104M
246 - 840 M
840 — 2,000 (I
~> 2,000 ]J.
1.00
1 2
FLUSHING TIME (hr)
104- 246 p
44- 104 (J.
246 — 840 H
840 - 2,000 y.
> 2,000 U.
1 2
FLUSHING TIME (hr)
a. Concrete, Rainfall 0.8 in./hr
b. New Asphalt, Rainfall 0.2 in./hr
Figure 46. Particle transport across street surfaces by type of pavement and rainfall i
intensity.
154
-------
KT 1-00 *=
44- 104 (JL
104- 246 (I
246 - 840 H
> 2,000 fl
840 - 2,000 H
\ I I I I
FLUSHING TIME (hr)
c. New Asphalt, Rainfall 0.8 in./hr
10.00
KEY FOR D & E
t = in./hr
Concrete
Concrete
Aged Asphalt
New Asphalt
New Asphalt
FLUSHING TIME ftir)
1 2
FLUSHING TIME (hr)
d. Transport of Total
Settleable Matter
e. Transport of Dissolved and
Colloidal Suspended Matter
Source:
Figure 46. Particle transport across street surfaces by type of
pavement and rainfall intensity.
Sartor, J.D., and G.B. Boyd, "Water Pollution Aspects of Street Surface Contaminants,"
USEPA Report No. EPA-R2-72-081 (NTIS No. PB 214 4O8), November, 1972.
The foregoing discussion has described both controlled and uncontrolled street
accumulation removal processes. The major focus of these procedures has been
in the area of discharge sources of receiving water quality impairment. Other
non-point sources of runoff pollution have been discussed at length earlier
in this section.
155
-------
INDIRECT RUNOFF POLLUTION SOURCES - SANITARY WASTEWATER FLOWS
The foregoing portions of this section have been devoted to identifying
the major apparent sources of pollution accessible to surface runoff. These
sources contribute to runoff pollution that enters receiving waters as point
discharges from separate storm sewer systemsand as general surface runoff.
They also contribute to the pollutional loads associated with discharges or
overflows due to the planned or unplanned addition of surface runoff to other
wastewater flows. While these may result from uncontrolled runoff inflow into
sanitary systems, the more general case is the overflow of combined sanitary
and storm sewage due to hydraulic overloading. From the standpoint of rela-
tive pollutional contributions, sanitary wastewater assumes an overall signifi-
cance because of its relative pollutional strength, and may be an additional
source of pollution in storm overflows.
Some reported values for the concentrations of various constituents within
raw domestic sewage are shown in Table 88. The values shown are average values.
The ranges shown reflect daily averages and not diurnal variations.
TABLE 88. REPORTED POLLUTANT
CONCENTRATIONS FOR RAW DOMESTIC
SANITARY WASTEWATER FLOWS (mg/I)
Pollutant . Average Concentration Range
Total Solids
Total Volatile Solids
Total Suspended Solids
Total Dissolved Solids
BOD5
COD
Total Nitrogen-N
1MO3-N
ISIH4-N
Total Phosphorus-P
Chlorides
Lead
Zinc
CoIiforrreMMPN/IQQml)
860
300
160
680
150
320
30
21
8
50
34
7
106 -
700-
100-
500-
100-
200-
24-
17-
6-
1,014
—
220
854
235
523
40
25
10
—
—
—
_
Sources: Pound, C.E.,and R.W. Crites, "Wastewater Treatment and Reuse by
Land Application: Volume I," USEPA Report No. EPA-660/2-
73-0060 (NTiS No, PB 225 940), May, 1973.
Cornell, Howland, Hayes and Merryfleld, Clalr A. Hill and
Associates, "Wastewater Treatment Study, Montgomery County,
Maryland," Reston, Virginia, November, 1972.
Thomas, R.E., et al., "Feasibility of Overland Flow for Treatment
of Raw Domestic Wastewater," USEPA Report No. EPA-660/2-
74-087 (NTIS No. PB 238 926/AS), December, 1974.
156
-------
In the same vein, some reported values for various levels of treatment of
domestic sanitary wastewater flows are shown in Tables 89, 90, and 91. These
values are presented to indicate the quality characteristics of raw and treated
wastewater flows. As such, they should be considered as informative but
suspect, insofar as they may not compare favorably with locally acquired data.
TABLE 89. REPORTED POLLUTANT
CONCENTRATIONS FOR PRIMARY
TREATED DOMESTIC SANITARY
WASTEWATER FLOW
(mg/l)
Pollutant
Average Concentration Range
66
48
115
9
23 172
23 102
71 158
5 18
TABLE 90. REPORTED POLLUTANT
CONCENTRATIONS FOR SECONDARY
TREATED DOMESTIC SANITARY
WASTEWATER FLOWS
(mg/l)
Pollutant Average Concentration Range
Total Solids 425
Total Volatile Solids
Total Suspended Solids 25
Total Dissolved Solids 400
BOD 25
Cod 70
Total Nitroyen-N 20
N03-N 8.2
NH4-N 9.8
Total Phosphorus-P 10
Chlorides 72 45 -TOO
Sulfate 125
Boron 0.8 0.7- 1.0
Sodium 50
Potassium 14
Calcium 24
Vlagnesium 0.2
iron 0.1
Lead 0.1
Mercury 5 mg/l
Nickel 0.2
Zinc 0.2
Sources Pound, C fc ., ana R.W. Crites, "Wasteweter Treatment and
Reuse bv Land Application: Volume I," USEPA Report
No. EPA 660/2 730060 (NTIS No. PB 225 940), May,
1973.
Reed. S.C.. et al., "Wastewater Management by Disposal
on the Land." Report 171, Corps of Engineers, Hanover,
New Hampshire. May, 1972.
TABLE 91. REPORTED POLLUTANT CONCENTRATIONS
FOR RAW WASTEWATERS AND ADVANCED TREATED DOMESTIC
SANITARY WASTEWATER FLOWS EMPLOYING CHEMICAL
COAGULATION, FILTRATION, AND ACTIVATED CARBON ABSORPTION
Total Solids
Total Volatile Solids
Total Suspended Solids
Total Dissolved Solids
BODrj
COD
Total Nitroyen-N
NO3-N
Total Phosphorus-P
Chlorides
4.4
3.4
1.4
2.3
12.9
5.9
Source Thomas R .6 ., et a I., "F-easibilitv of Overland f lew tor
Treatment of Raw Domestic Wastewater," USEPA Report
No. EPA 660/2 74087 (NTIS No. PB 238 926/AS).
December. 1974
Raw Wastewater
Average
Pollutant
Total Suspended Solids
BOD
COD
Total Phosphorus
Concentration
160
68
362
8
Tertiary
Average
(Range) Concentration (Range)
(100
(100
(200
(5.4
- 220)
- 235)
-523)
- 10)
6
10
27
0.4
(0
(1
(2
(0.1
- 13)
- 24)
-50)
- 1.0)
Treatment
Source Cornell, HowlantJ, Haves arid Merryfield, Clair A Hill and Associates, "Wastewater Treatf
Study, Montgomery County, Maryland," Reston, Virginia, November. 1972.
157
-------
Wet-weather combined sewer flows are often characterized in terms of the
admixing of dry-weather flow and surface runoff. However, a number of opinions
have been expressed concerning combined sewage. One viewpoint describes the
mixing of sanitary wastewater and storm runoff in terms of an initial period
in which dry-weather flows are pushed ahead of storm runoff; a subsequent
period in which the scouring of sewer depositions occur; and a third period
in which flows are an admixture of sanitary sewage and surface runoff. (73)
Overflows occur when the hydraulic capacity of the collection system, inter-
ceptor line or the dry-weather treatment facility is exceeded. Values for
interceptor sewer capacity have been reported as peak to average
dry-weather flow ratios in the range of 1.0 to 8.0, with a median of 4.0. In
terms of dry-weather treatment capacity, these values have been reported as
0.80 on an annual basis, with a range of from 0.5 to 1.50. (74) However, the
values that are reported above for dry-weather treatment capacity, are not
very representative of short-term runoff. There are studies that have produced
evidence of a strong correlation between the strength of sewage or surface run-
off and rate of discharge.
DIRECT AND INDIRECT RUNOFF DISCHARGE POLLUTION
One source of information on direct and indirect urban runoff pollution is
available through past studies of runoff discharges and combined sewer over-
flows from drainage basins in various parts of the country. A number of pub-
lished references were reviewed to determine the extent and adequacy of exist-
ing data sources. The following discussion relates the results of this in-
vestigation for both direct and indirect runoff. The emphasis, to the degree
an emphasis exists, will be on direct runoff. However, quality of combined
sewer overflows may be more accurately reflected by local conditions such as
the collection and interception system, and treatment plant hydraulic capacity.
Sampling Activities
The most realistic indications of direct and indirect runoff quality contri-
butions from a given drainage basin are those determined by direct measurement.
The selection of the sampling methods employed is an important determinant in
the quality of the collected data. In the review of published sources, sampling
activities were found to vary considerably. Composite samples have generally
been taken most often. These were usually obtained by automatic devices or
by manual grab sampling. Related flow measurements were made in only a few
instances. Similarly, flow-related discrete samples were collected rarely,
although discrete manual grab samples were often used in conjunction with
automatically collected composite samples.
Sampling site location also plays an important role in defining sampling
results. As an example, it is likely that combined sewer sampling generally
occurs within or at the discharge of a piped collection system in order to
reflect the quality of the flow to receiving waters. Separate system sampling
may occur at locations within the collection system or at the receiving water.
Very often, the separate system may take the form of earthen channels in whole
of in part. Sampling downstream of earthen channel sections add solid components
158
-------
and other pollutants during a meaningful runoff event due to gully and channel
erosion and other direct contributions. This condition would not be experienced
to the same degree in a combined sewer system. Thus, sampling from non-piped
or lined channels should be viewed with caution when considering solids content.
The sampling of urban runoff, and combined sewer overflows with all their
fluctuations and different characteristics, requires a high degree of monitor-
ing. Wide variations in the quality and quantity of direct and indirect run-
off, and the unpredictability of rainfall complicate monitoring activities.
Thus, it is difficult to obtain good information on the quality and quantity
of these flows.
Direct and indirect runoff sampling requires the measurement of both flow
and quality parameters throughout a storm event. This may be especially true
when first-flush quality and flow characteristics may be important. Automatic
sampling equipment is a desirable tool in runoff measurement. Unfortunately,
few automatic monitoring stations measure both flow and collect samples for
quality determinations. Although many samplers are actuated by floats, static
head transducers, and pressure switches; standard flow measuring devices such
as weirs and flumes are generally problematical in both sewered and channelized
collection systems due to the cost involved and difficulties in calibration.
Samples, collected either manually or with automatic equipment, may be
classified as discrete or composite samples. Discrete samples are collected
at selected intervals where each sample is retained for separate analysis.
As such, they represent water quality at a particular instant in time.
Discrete sampling and flow measurements taken at a sufficient frequency
during a flow"event provides"one of the most effective representations of run-
off quality variations with time and flow. Data collected on this basis can
provide useful information in the form of mass emission rates, and the
characterization of local first-flush effects.
Of discrete sampling, random grab samples are the easiest and most econo-
mical, but they are also least reliable in terms of representing quality flow
time characteristics unlessthese latter element are measured as well. An in-
dication of some of the problems associated with random grab samples is shown
in Figure 47.
Storm discharges vary in flow with respect to time and also in constituent
strength. Grab samples taken at the points of the hydrograph shown are rela-
tively unique. Mean values of pollutant concentrations taken on this basis
may not be very descriptive of the runoff or combined sewer overflow being
sampled. A more effective use of grab samples would be to verify samples
collected with an automatic sampling device.
159
-------
<
cc
i
ii
DENOTES COLLECTION OF
SAMPLES OF DIFFERENT
VOLUMES AT RANDOM TIMES
TIME
Source: Wullsehleger, Richard E., ET AL., "Recommended Methodology for the Study of Urban Storm Generated Pollution
and Control," USEPA Report No. EPA-600/2-76-145, Envirex, Inc., August 1976.
Figure 47. The problem of timing discrete grab samples
with respect to a runoff event.
Simple composite samples, are made up of a series of smaller samples of
constant volume that are collected and combined in a single container. Composite
sampling is an attempt to synthesize a sample which will represent the average
discharge characteristics over a period of time. Composite samplers may draw
a series of discrete portions into individual containers which are then added
together manually. As an alternative they may be drawn as a series of discrete
samples that are mixed automatically in a single container to make up the
composite sample.
Proportional flow composite samples are those collected in relation to flow
volumes to represent average constituents strength during the sampling period.
One approach to proportional flow composites is to collect equally sized samples
at a frequency that is inversely proportional to the volume of flow. As the
flow volume increases, the time interval between samples is reduced. The
samples are, thus, representative of constant flow volume increments. This
theoretical rainfall event is shown in Figure 48.
Another approach to the collection of flow proportioned composite samples
can be accomplished by increasing sample volumes in proportion to the flow,
but keeping the sampling frequency constant. -Figure 49, shows such a sampling
scheme with respect to a theoretical runoff hydrography.
160
-------
6 I-
D
O
1
Si 3
3
U
t = VARIABLE
DENOTES SAMPLES OF EQUAL VOLUME (SAME LENGTH ARROWS)
AT CONST ANT FLOW INCREMENTS (VARIABLE TIME)
TIME
Figure 48. Method of compositing equal volume samples at equal flow increments.
I
DENOTES COLLECTION OF A SAMPLE WHERE VOLUME
IS PROPORTIONAL TO THE RATE OF FLOW.
THE INDIVIDUAL SAMPLES ARE COMPOSITED INTO
ONE CONTAINER.
TIME
Figure 49. Method of compositing variable volume samples at fixed intervals.
Source: Wullschleger, Richard E., ET AL., "Recommended Methodology for the Study of Urban Storm Generated Pollution
and Control," USEPA Report No. EPA-600/2-76-I4S, Envirex, Inc., August 1976.
161
-------
The differences between constant flow volume and constant time composite
sampling techniques are relatively small and in most cases, both procedures
approach true average values. Interestingly, smaller time or volume incre-
ments between samples, will represent greater accuracy as to true runoff or
overflow conditions. The logical extreme of reducing these increments is
equivalent to an array of discrete grab samples at known values of flow and
time.
Sequential composite sampling is accomplished by taking composite samples
representative of a short period, with each being held in a separate container.
An example of sequential sampling may be taken as 24 one-hour composites that
may be used to represent daily quality characteristics. As previously noted
the accuracy of this sampling approach depends upon the length of the time
intervals selected with shorter intervals producing results closer to actual
conditions. It should be noted that sequential composites should also be
related to some average flow level to provide the most meaningful results;
but unfortunately this is not always the case in actual practice.
A recent study on sampling methods and equipment identified some of the most
desirable characteristics for a general sampling device. (75) These were:
1. Ability to take a sequentially timed series of discrete
samples. It should be possible to use an external signal
to allow sample volumes to be taken proportional to flow
rate or increments of flow. Five minutes should be the
minimum sampling interval.
2. Four different sample containers should be filled at each
sampling: (a) for solids and BOD testing to hold no pre-
servatives; (b) for metals and TOD analysis acid added to
preserve sample; (c) for nitrogen and phosphorus, HgCl2
added; and (d) sterilized containers used for bacterial
analysis. The fourth set of containers could also be used
for grease and oil, pesticides, or other tests.
3. Capability of using 1 to 3 liter sample containers so that
individual discrete sample analyses can be made.
4. Capability of programming the time interval at which samples
are taken, so the sampling interval can be short during the
early stages of the storm with longer intervals automatically
used as the storm continues.
5. Facilities hold 96 sample containers - this would allow samp-
ling every 10 minutes for four hours.
6. Refrigeration capabilities to hold samples at 4°C (39°F)
7. Capability of lifting samples 7.6 m (25ft) or more without
affecting sample size.
162
-------
8. Availability of a self-contained power source.
9. Capable of being automatically activated to indicate samp-
ling at beginning of storm.
10. Inlet line to be sufficiently large to eliminate problems
of plugging.
11. Inlet sampling velocity to be sufficiently high to keep heavy
particles in suspension throughout their flow to the sample
container.
12. Inlet device of such a configuration to allow obtaining a
representative sample throughout the depth of the stream
flow. Light floating material and heavy bottom sludge should
be included in each sample.
13. Inlet device should not plug easily and should be self-
cleaning. Sample lines should be purged so that the next
sample is not contaminated by any of the previously taken
samples,
The ideal sampling mechanism does not now exist, however, improved samp-
lers are being developed. In recognition of the problems in sampling and the
use of automatic samplers, the USEPA has developed a number of sampler design
goals similar in intent to the previously described characteristics. (76)
The success of a sampling program depends on the selection of the sample
site and the point at which samples are collected. Recent work in Durham,
North Carolina, showed that variations in results may be expected at differ-
ing depths within a runoff flow. (64) The selection of sampling methods
should be determined on the basis of the objectives to be served. If average
values for constituent concentrations over a number of events will suffice,
then composite sampling may produce sufficiently accurate results
If more definitive determinations of specific occurences related to flow
during an event are important, composite sampling may suffice if the flow or
time increment which activate sampling frequency are sufficiently short. As
the needs for accuracy increase, discrete sampling with related flow and time
measurements at a sufficiently high collection frequency may be required.
During a runoff event the composition and rate of flow may change contin-
uously. No single grab sample can adequately represent the flow and pollutant
concentration variations that may be experienced. An example of this variation
is shown in Figure 50. A large number of samples is required to characterize
the results of a given storm event. Thus, careful selection of the sampling
objectives to be served and the methods and procedures to be used, is necessary.
used, is necessary.
163
-------
140
2300
2330
2400 0030
O
O
O
Q
O
BJ
400
300
200
100
COD
BODB
2300
2330
2400
0030
2300 2330 2400 0030
TIME
Source! University of Cincinnati, "Urban Runoff Characteristics,"
USEPA Report No. 11024DQU1O/70 (NTIS No. PB 2O2
865), October, 1970.
Figure 50. Indirect runoff quantity and quality data.
Bloody Run Sewer Watershed.
164
-------
Direct (Storm) and Indirect(Combined) Runoff Discharge Characteristics
Some overall indications of the quality of direct and indirect runoff
discharges can be determined from the published reports of studies performed
in various locales. These locales have often been urban or urbanizing. On
occasion, discharge quality and quantity have been related to basin character-
istics and given rainfall events. Inconsistencies exist within this body of
information, however, due to variability in the research objectives being ad-
dressed, the pollutants evaluated, the sampling technique employed, and the
measurements performed. The majority of existing direct and indirect runoff
discharge quality information appears in the form of mean pollutant concentra-
tions or averages of sample results from one or more runoff events. These
average results are at times taken without regard to rainfall-runoff relation-
ships and other variations in time.
Some overall indications of the quality of direct surface runoff dis-
charges are given in Table 92. Similarly, mean concentrations of various pol-
lutants found in measured combined sewer overflows are depicted in Table 93.
This form of data provides an estimate of average quality characteristics.
Time-related effects such as the "first-flush" are not reflected in these values.
A simple evaluation of these flows indicates that direct runoff generally
has solids concentrations equal to or greater than untreated sanitary sewage.
BOD5 concentrations are approximately those of secondary effluents. Bacterial
contamination of separate storm wastewater is about two to four orders of
magnitude less than untreated sewage. Combined sewer overflows and sanitary by-
passes generally average less than half the strength of untreated sewage, but
are important because of their volumetric magnitude. A rainfall intensity of
2.5 cm/hr (1 in/hr) may produce flows up to 100 times normal dry-weather flows.(77)
Discharge quality, time and runoff flow data have been published in only a
few locales. Foremost among these is a published study from Durham, North Caro-
lina (64) that studied a separate storm runoff collection system in terms of
the quality of surface runoff with respect or runoff quantity during a number
of rainfall events.
The Durham study represents perhaps the most advanced approach to the
characterization of runoff quality to date, insofar as it proceeds from real
discrete data taken with careful attention to runoff and basin characteristics.
A summary of further findings from this study is shown in Table 94. It should
be remembered that these findings are basin specific and as such, reflect the
characteristics of the catchment studied. Therefore, the transferability of
these findings to other basins may well be limited.
As to the quality characterization of runoff discharges, it is apparent
from the foregoing that the available discharge information leaves much to be
desired. The original objective for the majority of this information was
obviously to produce order-of-magnitude estimates of the pollution represented
by runoff discharges. In fulfilling this end, the reported average data is
successful. Realistic discharge quality data, however, requires considerably
more. Thus, further research in this area of investigation is indicated.
165
-------
TABLE 92. MEAN DISCHARGE QUALITY DATA FOR SEPARATE STORM SYSTEMS
CTs
ON
Location
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Tulsa, Okla.{l)
Tulsa, Okla.
Tulsa, Okla.
Tulsa, Okia.
Tulsa, Okla.
Tulsa, Okla.
Tulsa, Okla.
Tulsa, Okla
Tulsa, Okla.
Tulsa, Okla.
Tulsa, Okla.
Tulsa, Okla.
Tulsa, Okla.
Tulsa, Okla.
Tulsa, Okla.
Washington, DC*2'
Madison, WisJ3)
Atlanta, GaJ4'
Atlanta, Ga.
Atlanta, Ga.
Seattle, WashJs)
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Roanoke, Va. (e)
Roanoke, Va.
Roanoke, Va.
Minneapolis, Minn.'7'
Cincinnati, Ohio'8'
No. Runoff
Events
14
16
16
15
13
10
18
8
11
11
11
11
10
5
8
„
..
-
.,
„
,.
-
..
-
_,
4
-
No. of
Samples
36
23
48
46
50
15
60
13
16
34
26
27
30
18
22
64
.»
„
-
.,
..
_
„
..
-
..
84
_
Total
Solids
mg/1
2,242
275
680
616
271
346
413
382
417
431
575
199
469
592
273
2.166
280
-
„
—
-
--
„
460
514
937
..
--
Susp.
Solids
mq/l
2,052
169
280
340
136
195
84
240
260
300
401
89
332
445
183
.*
,.
„
—
168
34
305
54
--
..
„
-
227
BODg
mg/l
13
8
8
14
18
12
8
15
10
11
14
8
15
11
10
19
..
7
20
26
27
42
6
10
18
20
26
26
17
COD
mg/l
110
45
65
103
138
90
48
115
117
107
116
45
88
58
41
321
„
28
84
67
266
96
76
57
-
--
—
164
111
Total
Organic
Carbon
mg/l
43
22
22
42
48
34
15
37
35
28
33
26
35
29
34
...
'..
..
--
..
-
• --
--
„
-
-
-.
_
-
Organic
Kjeldahl
N03 Nitrogen
ma/I mg/l
-- 1.11
-- 0.95
-- 1.48
- 0.97
- 0.72
- 0.65
- 0.80
- 0.60
- 0.67
-- 0.88
- 0.66
- 0.39
-- 1.46
- 0.06
-- 0.36
..
- 3.5
..
..
„
0.58 --
0.33 --
0.66 --
0.51 --
_
-
—
-
..
Soluble
Nas Total On the
NH3 N P04 P04
ma/I mg/l mg/I mg/l
.. 3.49
- 0.35
1.92
- 1.05
-- 0.87
~ 0.86
- 0.67
- 1.15
1.02
.. 0,70
,. 1.11
0.54
1.13
- 0.39
- 0.31
- 2.1 1.3 --
- 0.98 --
- 0.4
-- 0.3
-- 1.6 --
1.87 -- -- 2.38
0.38 -- - 0.55
0.18 -- - 0.35
0.18 -- -- 0.20
..
- 3.1 1.1 -
Total
P Chloride
mg/l mg/l
- 11
-- 10
- 13
- 19
3
9
- 49
- 10
5
- 10
6
4
- 15
-- 13
2
..
..
„
--
_
..
_
..
..
-
--
..
0.62 -
--
-------
TABLE 93. MEAN DISCHARGE QUALITY DATA FOR COMBINED SEWER OVERFLOWS
Total Susp.
No. Runoff No. of Solids Solids
Location Events Samples mg/l mq/l
1
3
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
*3C
nfi
Washington. DC*9' 25
Washington, DC 4
Washington, DC 2
Washington, DC
Portland, Ore.'10'
Philadelphia, Penn.(n) 44
Milwaukee, Wis.'12> 26
Chippewa Falls, Wis.{13'
Atlanta, Ga.'14'
Atlanta, Ga.
Atlanta, Ga.
Seattle. Wash.'15'
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
Seattle, Wash.
San Francisco, Cal.'16' 50
Detroit, Mich.'17'
Cleveland, Ohio'18'
Cincinnati, Ohio'19' 4
Bucyrus, Ohio'20'
Bucyrus
Bucyrus
^Arramrmfn f*ll '^t| c
rnlumhin:'2*) -30
94 883
574
103 •- " 106
178
150 378 166
360 - 287
..
..
340
212
1,464
53
64
280
96
207
200
194
777
317
192
245
93
286
209 68
60± •• 634
177 590 234
33 1,073
-- 1,647
863
916
1R 1R1
I Q I Q I
Udd 1 1A
B000
mg/I
71
1 "31
U I
137
~j~l
1 I
49
49
170
210
84
133
27
62
68
34
51
148
27
49
15
33
235
66
19
66
39
42
49
72
92
210
170
107
168
on 7
£\}t
in1?
COD
mg/l
381
242
161
442
164
286
266
196
353
371
288
736
100
210
160
250
817
211
200
272
124
165
155
308
438
372
476
391
OA1
NO3
mg/l
-
..
--
0.27
0.34
0.51
0.54
0.54
1.52
0.84
0.44
0.21
0.22
0.33
0.82
-
0.42
0.87
1.11
_
—
„
4.54
3.79
3.89
N as Total
NH3 N PO4
mq/l mg/l mg/l
1.5 3.5 3.0
- 3.5 1.0
-- 5.5
-• - 6.5
-- -- 1.7
-- - 2.3
0.23 --
1.98 -
5.08 --
0.78 -•
1.36 -
1.34 --
0.36 -•
2.18 --
0.91 --
2.75 --
3.0 --
2.5 -
1.38 -
6.25 -
2.05 -
1.26 -
_
- 4.5 --
.,
3.13 --
1.08 ••
2.7
Total
P Chlorides
mg/l mg/I
--
..
-
..
..
..
-
..
..
..
..
..
..
..
..
..
..
...
1.45 --
- 203
-- 120
- 147
SOURCES FOR TABLES 92 AND 93
1 American Public Works Association, "Water Pollution Aspects of Urban Runoff," USEPA Report No.
11030DNS01/69 {NTIS No. PB 215 532), January, 1969.
2American Public Works Association, "Combined Sewer Regulation and Management," USEPA Report No.
110220MU08/70 (NTIS" No. PB 195 676), July, 1970.
""Lager, J.A.,and W.G. Smith, "Urban Stormwater Management and Technology an Assessment," USEPA Report
No. EPA-670/2-74-040 (NTIS No. PB 240687/LK) May, 1974.
167
-------
4Waller, D.H., "Pollution Attributable to Surface Runoff and Overflows From Combined Systems," Atlantic
Industrial Research Institute, Halifax, Nova Scotia, April, 1971.
5 Burgess and Niple, Ltd., "Stream Pollution and Abatement from Combined Sewer Overflows, Bucyrus, Ohio,"
USEPA Report No. 11024FKN11/69 (NTIS No. PB 1B5 162), November, 1969.
6Davis, P.L.and F. Borchardt, "Combined Sewer Overflow Abatement Plan, Des Moines, Iowa," USEPA Report
No. EPA-R2-73-170 (NTIS No. PB 234 183), April, 1974.
'Municipality of Metropolitan Seattle, "Maximizing Storage in Combined Sewer Systems," USEPA Report No.
11022ELK12/71 (NTIS No. PB 209 861), December, 1971.
8 Roy F. Weston, Inc., "Combined Sewer Overflow Abatement Alternatives, Washington, D.C.," USEPA Report
No. 11024EXF08/70 (NTIS No. PB 203 680), August, 1970.
9
Municipality of Metropolitan Seattle, Op. Cit.
10
Ibid.
11 Rex Chainbelt, Inc., "Screening/Flotation Treatment of Combined Sewer Overflows," USEPA Report No.
11020FOC01/72 (NTIS No. PB 215 695), January, 1972.
12
'.Lager, J.A., and W.C. Smith, Op. Cit.
13 Rex Chainbelt, Inc., Op. Cit.
Mlbid.
lslbid.
"Waller, D.H., Op. Cit.
17 Ibid
1'Wilkinson, R-, "The Quality of Rainfall Runoff Water from a Housing Estate "Journal of the Institute of Public
Health Engineers, 1962.
1'Sylvester, R.O., "An Engineering and Ecological Study for the Rehabilitation of Green Lake," University of
Washington, Seattle, Washington, 1960.
20iColston, N.V.,"Characteristics and Treatment of Urban Land Runoff," USEPA Report No. EPA-670/2-74-096
(NTIS No. PB 202 86B), December, 1974.
11 Waller, D.H., Op. Cit.
"Ibid.
168
-------
TABLE 94. REGRESSION EQUATIONS PREDICTING POLLUTANT CONCENTRATION
(mg/I) IN URBAN LAND RUNOFF IN A NATURAL CHANNEL
CORRECTED TO FLOW AT MID-DEPTH
Pollutant
mg/I
COD
TOC
TS
TVS
TSS
VSS
Kjel, N.
Total P.
A!**
Ca
Co**
Cr
Cu**
Fe
Pb
Mg
Mn
Ni**
Zn
113. CFS0-11 TFSS-°'2a
32. CFS°'° TFSS-'28
420. CFS0-14 TFSS-'18
130. CFS0-09 TFSS-'11
222. CFS0'23 TFSS-'16
44. CFS0-18 TFSS-'17
0.85 CFS0-87 TFSS--29
0.80 CFS0-03 TFSS"-29
10. CFS0-05 TFSS~-15
12.5 CFS"-4 TFSS"'09
0.07 CFS0-18 TFSS*'13
0.18 CFS""'04 TFSS*'06
0.08 CFS0"10 TFSS*-08
4.6 CFS0'24 TFSS-'18
0.27 CFS0-125 TFSS-'29
10. CFS"'02 TFSS--16
0.45 CFS0'11 TFSS-'27
0.12CFS0-03 TFSS--01
0.22 CFS0-10 TFSS-22
•CFS = Cubic Feet Per Sacond
* TFSS = Time from Storm Start (Hours)
* "Mid-Depth Correction Assumed as 0.9
Source: Colston, N.V., "Characterization and Treatment of Urban Land Runoff," USEPA Report No. 670/2-74-096
(NTIS No. PB 2O2 865), December, 1974.
169
-------
COMPARISON OF WET AND DRY WEATHER FLOWS
A number of the characteristics of runoff pollution have been discussed
at some length in this section. These have included consideration of a number
of the sources of direct runoff pollution—transportation activities, vegeta-
tive debris, air pollution depositions, erosion products, catch basin depositions,
roof drainage, animal wastes, and first flush contributions. In addition, street
surface potentials were also considered as a direct runoff pollutional source.
While not wholly definitive, this review of the sources of pollution, pro-
vies a number of insights into the current state of the art of source assessment.
In addition, it provides a concept of the multiplicity of contributing sources
and suggests areas for further research.
Another area of review concerned the characterization of direct runoff pol-
lution from the viewpoint of runoff dicharge measurements. For the most part,
existing data collection in this area have been for the purposes of gross run-
off characterization. These reported results have been presented most often
as average values for various measures of pollution. A more detailed character-
ization of discharge pollution, however, is also available but in a limited
form. This considers the magnitude and nature of various pollutional concentra-
tions in terms of flow and time, as determined from the detailed analysis of a
single basin in Durham, North Carolina. (64)
In view of the variety of potential contributions to runoff pollution, a
number of questions must arise as to their relative effects and relationships.
The following discussion evaluates these issues from the standpoint of a hypo-
thetical case study, in terms of existing assessment methods. It is anticipated
that this case study evaluation will provide approximate estimates of the magni-
tudes of pollution to be contributed from these various sources, based on
available data and existing analytical methods. In addition, some estimates
of other pollutional contributions from other wastewater flows will be developed
for the purposes of comparison.
Since information on sources of pollution are derived from a variety of
published reports, a hypothetical approach will serve as a practical illustra-
tive mechanism to demonstrate estimates of source contributions. It will also
show those contributing elements for which little or no data now exists.
Finally, it will point out the relative magnitudes of contributions from
various wastewater flows for similar time periods.
Hypothetical Case Comparisons
The hypothetical case considered in the following analysis is based on an
urban area of approximately 260 krn^ (100 mi^) and an overall population density
of 21.25 persons/ha (8.6 persons/ac). The distribution of land use within this
area was assumed to be as shown in Table 95.
170
-------
TABLE 95. HYPOTHETICAL LAND-USE
DISTRIBUTION
Land Use Percent of Area
Residential 65
Commercial 6
Industrial 12
Park/Undeveloped 17
100
Source: Land-use distribution as derived from data for
the City of Denver, Colorado.
The general configuration of the hypothetical urban area is assumed to
be approximately square, and it is tributary to a receiving stream with a main
channel length of 16.1 km (10 mi) and a gradient of 0.25 percent.
Precipitation data from two individual storm events produced hydrographs
for descriptive purposes as shown in Figure 51. The hydrographs show esti-
mates of total flows for the rainfall distribution indicated. The two rain-
fall events selected were used to demonstrate conditions where runoff from
pervious areas would or would not be contributed to the overall runoff from
the area. Pervious contributions were estimated for the second rainfall event
only.
A generalized rainfall distribution was assumed to fall over the entire
basin; this condition is unlikely to occur in reality, but it proves helpful
in the analysis. The hydrographs are broken into their components for flows
attributable to street imperviousness, non-street imperviousness, and pervious
areas where they occur. Flows from non-street impervious areas are assumed
to contribute wholly to total flows although, in reality, roof drainage may
be discharged to pervious areas on occasion.
Estimates of total and street imperviousness were determined from the
generalized expressions which were developed and are described in Section 4,
Data Development for Application of the STORM Model in 50 Urbanized Areas.
Percent Total Imperviousness = 104.95 - 81.27(0.974)PD
Percent Street Imperviousness = 17.06 - 14.56(0.839)PD
where: PD = population density, persons/ha (persons/ac)
Application of these empirical expressions resulted in an estimated over-
all total imperviousness of 39.9 percent. Imperviousness attributable to
street paving was estimated to be 13.8 percent, and non-street imperviousness
was thus assumed to be 26.0 percent, more or less.
171
-------
113 4,000
85 3.000
57 2,000
28 1,000
in/min cm/min
0 Runoff Hyetograph
0.25 0.8 Event No 1
0.50 1.2
9 10 11 12 13 14
in/min cm/min
Runoff Hyetograph
Event No 2
Figure 51. Hypothetical Runoff Hydrographs
172
-------
Direct Runoff Pollution
Direct runoff pollution contributions were estimated in terms of those
parts of the urban environment that contribute to the overall runoff and the
pollutants that these different parts are likely to contribute. The major
limitation associated with this approach was the availability of data on the
pollutional characteristics of these runoff sources.
The major sources of contribution considered were those associated with
rainfall, street surface areas, impervious rooftops, parking lots, sidewalks
and other areas, and pervious areas such as lawns and undeveloped sites. The
pollutional contributions associated with rainfall itself were based upon
contaminant levels measured in Cincinnati, Ohio. (78) On the basis of the run-
off estimated from street and non-street impervious areas, rainfall pollutional
contributions could be those presented in Table 96.
TABLE 96. POTENTIAL POLLUTIONAL CONTRIBUTIONS ADDED BY RAINFALL
Pollutant
Suspended Solids
Volatile Sol'rds
Inorganic Nitrogen
Hydrolyzable Phosphates
BOD=
Event
Ib,
46,860
13,410
2,440
850
Unknown
No. 1
kg.
20,820
S.088
1,108
386
Event
Ib.
104,550
30,860
5,B50
1,930
Unknown
No. 2
kg.
47,466
13,874
2,520
876
Mass Emission Rate
Ib/ac-in kg/ha-cm
74,000
21,600
3,930
1,370
Unknown
33,067
9,652
1,756
612
Source; Derived from data reported In "Urban Land Runoff as a Factor m Stream Pollution," Weibel, S.R., Anderson, R.J.,
Woodward, R.L., Journal Water Pollution Control Federation, Vol. 36, No. 7, July, 1964.
The pollutional contributions for street surface areas were derived from
the general tabulation of street surface contaminants discussed previously.
A composite value for the dust and dirt accumulation based on the percent of
each land use and the relative road density attributable to each was computed
to be 33.7 kg/curb-km/day (119.6 Ib/curb-mi/day). The dust and dirt values
and related potential pollutant concentrations employed are shown in Table 97.
173
-------
TABLE 97. DUST AND DIRT AND POTENTIAL POLLUTANT
CONCENTRATIONS USED WITH EVENTS 1 AND 2
Pollutant Concentration
Dust and Dirt 32.6 kg/curb-km/day (119.6 Ib/curb-mi/day)
BOD5 5,030 mg/kg
COD 46,120 mg/kg
Kjeldahl Nitrogen 640 mg/kg
Total PO4 170 mg/kg
Ortho PO4 53 mg/kg
Cadmium 3.1 mg/kg
Lead 1,970 mg/kg
Zinc 470 mg/kg
Average street cleaning frequencies were also composited to produce a value
for 43 days between cleanings for all land uses. (52)
The accumulation period of street surface contaminants was determined
through comparison of composite street cleaning frequencies and the analysis
of average probable rainfall frequencies based on Chicago rainfall data. (15)
This analysis was selected since the Chicago data in total simulated the
annual national average precipitation. The findings of this analysis defined
the average probable rainfall occurrence period as approximately four days for
events of 0.1 cm (0.04 in) or more, and 20.5 days for precipitation events of
1.2 cm (0.5 in) or more. On this basis, it was assumed that the average range
of accumulation period would vary from 4 to 20.5 days. In this hypothetical
case, street surface accumulations were considered to start with clean street
conditions.
The total solids accumulated over this accumulation period and removed
by the runoff from the described precipitation events, is shown in Table 98,
The related contributions for select conservative and non-conservative
pollutants are also shown in this tabulation for both of the rainfall events.
In addition to solids measures, these include amounts of oxygen demand,
nutrients, and some metals. The BOD values shown were derived from standard
analyses techniques and as such, are only theoretical estimates. They repre-
sent possible minimum values. BOD values, so determined, have been proposed
to be questionable due to the toxic constituents in runoff and other inherent
factors, and their inhibitive effect on biological activity. (64)
174
-------
TABLE 98. ESTIMATED TOTAL SOLIDS AND POLLUTANT CONTRIBUTIONS
COMPUTED FOR EVENTS 1 AND 2
Pollutant
Total Solids
BODB
COD
Kjeldahl Nitrogen
Total PO4
Ortho PO4
Cadmium
Lead
Zinc
Event
Ib
1,797,000-9,209,500
9,040-46,320
82,880-424,740
1,150-1,570
210-1,570
100-490
6-29
3,540-18,140
840-4,330
No. 1
kg
815,838-4,181,113
4,104-21,029
37,628-192,832
522-2,674
95-713
45-222
3-13
1,607-8,235
381-1,966
Event No.
Ib
1,897,000-9,722,100
9,540-48,900
87,490-448,380
1,210-6,220
320-1,650
100-620
6-30
3,740-19,150
890-4,570
2
kg
861,238-4,413,833
4,331-22,200
39,720-203,564
549-2,824
145-749
45-236
3-14
1 ,698-8,694
404-2,075
The pollutlonal contributions associated with non-street impervious areas
were also computed for the two defined runoff events. Unfortunately, the
data available for estimation purposes were limited to suspended solids and
metals such as cadmium, lead, and zinc. For the purposes of computation the
same accumulation period as employed for street surface accumulations was used
in connection with the basic dustfall information, and are shown in Table 99.
TABLE 99. DUSTFALL AND POLLUTANT POTENTIALS
USED WITH EVENTS 1 AND 2
Land Use
Residential
Commercial
Industrial
Dustfall
kg/ha/day
(Ib/ac/day)
120
(107)
208
(185)
269
(240)
Cadmium
kg/ha/day
(Ib/ac/day)
1.27x 1Q'5
(1.13x 10'5)
2.07 x 10~6
(1.85x10"s)
2.42 x 10'5
(2.16 x 10'5)
Lead
kg/ha/day
(Ib/ac/day)
1,73x 10'3
(1,54x 10~3)
4.15 x 10'3
(3.70 x 10'3)
3.23 x 10'3
(2.88 x 1Q-3)
Zinc
kg/ha/day
(Ib/ac/day)
1.84x 10~3
(1.64x 10'3)
3.1 x 10'3
(2.77 x 10"3)
4.15 x 10'3
(3.70 x 1Q-3)
Source:
Hunt, W.F,,.at al., "A Study of Trace Element Pollution of Air in 77 Midwestern Cities," Paper presented at the Fourth
Annual Conference on Trace Substances in Environmental Health, University of Missouri, June, 1970.
The computed data obtained from this estimating process are shown in
Table 100.
175
-------
TABLE 100. ESTIMATED SUSPENDED SOLIDS AND POLLUTANT CONTRIBUTIONS
FROM DUSTFALL FOR EVENTS 1 AND 2
Pollutant
Suspended Solids
Volatile Suspended Solids*
BOD6'
Cadmium
Lead
Zinc
Event
Maximum
kg
(Ib)
16,802,742
(37,043,900)
5,040,822
(11,113,170)
4,672
(10,300)
1.8
(4.1)
263
(580)
281
(620)
No. 1
Minimum
kg
Ob)
3,278,593
(7,228,100)
983,578
(2,168,430)
4,672
(10,300)
0.4
(0.8)
52
(114)
54
(120)
Event
Maximum
kg
(Ib)
17,737,909
(39,105,600)
5,321,372
(11,731,680)
10,696
(23,580)
1.9
(4.3)
276
(610)
300
(660)
No. 2
Minimum
kg
(Ib)
3,461,073
(7,630,400
1,038,322
(2,289,120)
10,696
(23,580)
0.4
(0.8)
54
(120)
59
(130)
'Volotito Sujpondod Solids estimated at 30 percent of suspended solids and an average median BODg value of 4.6 mg/l from
W«ll*r, D.H., "Pollution Attirutable to Surface Runoff and Overflows from Combined Sewer Systems," Atlantic Industrial
Rouurch I nit I tu to, Halifax, Nova Scotia, April, 1971.
As previously noted, the foregoing summary does not reflect all of the
pollutants involved in non-street impervious runoff. However, it provides an
estimate of contributions for which some data are available. The dustfall data
used to estimate non-street impervious runoff applies most appropriately to roof
runoff as opposed to parking lot or sidewalk runoff.
The pollutional contributions due to pervious area runoff were estimated for
the second event only. Under the assumptions made in this analysis, pervious
area runoff was estimated for this event and not for the initial event. The
pollutional contributions in this analysis were limited to sediment (total
solids) as estimated by the Universal Soil Loss Equation, and nitrogen and phos-
phorus, computed as a function of sediment. (14) It should be noted that the
Universal Soil Loss Equation and other estimating methods are used for annual
estimates. In the analysis proposed in this section, these are assumed to apply
as well for the short-term events studied.
The results of this analysis are shown in Table 101. The results shown are
limited to only 3 pollutants due to the limited availability of data.
TABLE 101, ESTIMATED SOLIDS AND POLLUTANTS
CONTRIBUTIONS FROM PERVIOUS AREAS
FOR EVENT 2
Event No. 2
Pollutant
Total Solids
Total Nitrogent
Phosphorus (P2OS)
Ib
12,371,100
1,410,300
427,000
kg
5,616,479
640,276
19,386
176
-------
A summary of the findings of the foregoing analysis are compiled in
Table 102. The data shown within this tabulation are low estimates for all
pollutants, with the exception of total solids and suspended solids. Similar-
ly, a summary of results for the second rainfall event is shown in Table 103.
TABLE 102. SUMMARY OF ESTIMATED DIRECT POLLUTIONAL CONTRIBUTIONS FROM
VARIOUS SOURCES FOR EVENT 1
Source
Rainfall
Streets
Non-Street
Imperviousness
Pervious
Totals
(Range)
Total Solids
kg (Ib)
20,820
(45,900)
Win. 815,101
(1,797,000)
Max. 4,177,337
(9,209,500)
Win. 3,862,818
(8,516,100)°
Max. 19,130,204
(42,175,100)
0
Min. 4,698,739
(10,359,000)
Max. 23,328,361
(51,430,500)
Suspended Solids
kg (Ib)
20,900
(45,900)
630,853
(1,390,800)"
•3,285,352
(7,243.000)
3,270,594
(7,228,100)
16.802,743
(37,043,900)
0
3,930,267
(8,664,800)
20,108,915
(44,332,800)
BOD 5
kg (Ib)
link.
4,082
(9,000)
21.001
(46,300)
4,672
(10,300)
0
8,754
(19,300)B
25,673
(56.600)
COD
kg (Ib)
Unk.
37,603
(82,900)
7,192,640
(424,700)
Unk.
0
37,600
(82,900)b
192,640
(424,700)
PO4 Cadmium
kg (Ib) kg (Ib)
386
(850)
141
(310)
712
(1,570)
Unk.
0
526
(1,160)b
1,098
(2,420)
Unk.
3
(6)
14
(30)
0.5
(1)
1.8
(4)
0
3
(7)D
15
(34)
Lead
kg (Ib)
Unk.
1,588
(3,500)
78,210
(18,100)
45
(100)
272
(600)
0
1.633
(3.600)"
78.482
(18,700)
Zinc
kg (Ib)
Unk.
363
(800)
1,950
(4,300)
45
(100)
272
(600)
0
7.408
(900)°
2.223
(4.900)
Estimated fron
i estimating function in the form suspended solids - 0.79 (Total Solids) - 22, in mg/l derived from moan discharge data.
Low estimates due to incomplete available data.
TABLE 103. SUMMARY OF ESTIMATED DIRECT POLLUTION CONTRIBUTIONS FROM
VARIOUS SOURCES FOR EVENT 2
Source
Rainfall
Streets
Non-Street
Imperviousness
Pervious
Total Solids
kg (Ib)
47,446
(104,600)
Min. 860,460
(1.897,000)
Max. 4,432,527
(9,722,100)
Min. 4,277,671
(9,430,700)
Max. 20,394,903
(44,963,300
5,611,407
(12,371,100)
Min. 10,796,984
(23,803,400)
Max. 30,463,603
(67,161,100)
Suspended Solids
kg (Ib)
47,446
(104,600)
650,902
(1, 435,000) '
3,453,997
(7,614,800)
3,461.073
(7.630,400).
17,737,909
(39,105,600)
4,418,012
(9,740,100)1
8,577.432
(18,910,100)
25,657.364
(56,565,100)
BOD5
kg (Ib)
Unk.
4,309
(9,500)
722,226
(49,000)
10,705
(23,600)
Unk.
15,014
(33.100)2
32,931
(72,600)
COD
kg (Ib)
Unk.
39,689
(87,500)
203,390
(448,400)
Unk.
•v.
Unk.
39,689
(87.500)2
203,390
(448,400)
PO4 Cadmium Lead
kg (Ib) kg (Ib) kg (Ib)
7,875
(1,930)
145
(320)
740
(1,650)
Unk.
Unk.
1,021
(2.250)2
1,624
(3,580)
Unk.
3
(6)
14
(30)
0.5
(1)
2
(4)
Unk.
3
(7)2
15
(34)
Unk.
1,678
(3,700)
78,709
(19,200)
54
(120)
277
(610)
Unk.
1,733
(3.820)2
8,986
(19.810)2
Zinc
kg (Ib)
Unk.
408
(900)
2,087
(4,600)
59
(130)
299
(660)
Unk.
467
(1,030)z
2,386
(2.386)
NOTES:
1
Estimated value from an estimating function in the form suspended solids (mg/l) = 0.79 (Total Solids, mg/l) — 22 derived from available mean discharge data.
Low animates due to incomplete data.
177
-------
This event reflects sediment contributions from pervious areas in addition
to the other sources previously described. For this event, sediment estimates
represented from 18 to 52 percent of the solids contributed.
An alternative approach to the estimation of direct pollutional contribu-
tions was employed for the first event, using the discharge characterization
equations developed in Durham, North Carolina. (64) The results of this compu-
tation appear in Table 104, This characterization was performed on an urbanizing
basin and represent the response of that basin to experienced rainfall events.
As such, the magnitude of the solids estimated by this method are considerably
less than, those previously identified in Table 102. The other pollutants iden-
tified, however, generally fall within the range of previously estimated values,
with the exception of lead which is somewhat less.
TABLE 104. ESTIMATED DIRECT POLLUTION
CONTRIBUTIONS FOR EVENT 1 COMPUTED FROM THE
DURHAM, NORTH CAROLINA, CHARACTERIZATION
DATA
Event No. 1
Pollutant
Suspended Solids
COD
Lead
Zinc
Ib
3,445,200
555,000
1,450
1,200
kg
1,564,121
251,970
638
545
Other Wastewater Flows
Other wastewater flows for the hypothetical community might include raw
domestic sanitary sewage, primary treatment domestic wastes effluents, secondary
treatment domestic wastes effluents, and those domestic wastes effluents that
result from advanced treatment processes. An average daily per capita flow of
515 1 (136 gal) and the general characterization of these flows designated as
resulting from indirect runoff pollution sources as previously discussed, were
applied to hypothetical case conditions to prepare the estimated contributions
shown in Table 105. These estimates apply to the period of flow encompassed by
the runoff period.
178
-------
TABLE 105. ESTIMATED POLLUTIONAL CONTRIBUTIONS FROM OTHER
WASTEWATER FLOWS DURING EVENT 1 AND 2
Pollutant
Total Solids
Suspended Solids
BOD
COD
Lead Zinc
Raw
kg Ib
137,108
24,515
23,926
51,030
5,403
1,135
302,000
56,200
52,700
112,400
11,900
2,500
Primary
kg ib
—
10,533
7,673
18,342
—
—
23,200
16,900
40,400
—
—
Secondary
kg Ib
67,737
3,995
3,995
11,168
16
32
149,200
8,800
8,800
24,600
35
32
Advanced
kg Ib
—
953
1,589
4,313
—
—
—
2,100
3,500
9,500
—
Comparison of Waste Contributions
On the basis of the foregoing estimates, some simple comparisons of rela-
tive contributions may be made for the period covered by the selected short-
term runoff events. The comparison for both events is shown in Table 106.
TABLE 106. COMPARISON OF WASTE CONTRIBUTIONS FOR EVENTS 1 AND 2
Source
Direct Runoff
Event 1
Event 2
Raw Domestic
Sanitary
Primary Treated
Domestic Sanitary
Effluent
Secondary Treated
Domestic Sanitary
Effluent
Advanced Treatment
Domestic Sanitary
Effluent
Total Solids
kg (Ib)
4,698,739
(10,359,000)
1 0,796,984
(23,803,400)
136,984
(302,000)
—
—
67,676
(149,200)
—
—
Suspended Solids
kg (Ib)
3,930,267
(8,664,800)
8,577,432
(18,910,100)
24,492
(56,200)
10,523
(23,200)
3,992
(8,800)
953
(2,100)
BOD
kg (Ib)
8,754
(19,300)
15,014
(33,100)
23,904
(52,700)
7,666
(16,900)
3,992
(8,800)
1,588
(3,500)
COD
kg (Ib)
37,603
(82,900)
39,689
(87,500)
50,984
(112,400)
18,325
(40,400)
11,158
(24,600)
4,309
(9,500)
Lead
kg (Ib)
1,633
(3,600)
1,724
(3,800)
5,398
(11,900)
—
—
16
(35)
—
—
Zinc
kg (Ib)
408
(900)
454
(1,000)
1,134
(2,500)
—
—
32
(70)
—
—
On the basis of these estimates, direct runoff contributions of solids
materially exceed those associated with domestic sanitary wastewater flows at
any level of treatment. Domestic sanitary flows represent two percent or
less of the total estimated solids loadings. Estimated BOD contributions
from direct runoff are greater than those from secondary and advanced treat-
ment domestic wastewater effluents. However, these contributions are less
179
-------
than for raw wastewater, and about the same as primary treatment effluents,
for the events evaluated. Similar comparisons also exist for COD contribu-
tions, except for primary treated domestic sanitary effluents. In this
instance, direct runoff contributions exceed those of primary treatment
effluents.
Direct runoff contributions represent at least 44 percent of the total
pollutional load on an annual basis. In the category of metal contributions,
direct runoff produced higher levels of lead and zinc for treated effluents,
but not for raw domestic wastes. These contributions may be on the order
of at least 24 and 28 percent per annum, respectively, of the total lead and
zinc contributions.
The foregoing comparison indicates that the relative contributions of
pollutants associated with direct runoff can be significant during a runoff
event. The estimations shown do not encompass all pollutants from all direct
runoff sources. As such, they represent relatively conservative estimates;
and the comparisons suggested tend to minimize the contributions of direct
runoff.
The relative contributions of direct runoff will be found to diminish as
the time intervals investigated become longer. The investigation of longer
term comparative contributions will be considered in Section V of this report
for a number of individual urbanized areas across the country, and finally
for all urbanized areas. These evaluations will provide some comparative
results that will be helpful in better identifying these time-increment effects.
180
-------
SECTION IV
URBAN DATA DEVELOPMENT TO ASSIST
MODELLING ACTIVITIES
One of the key elements of this study has been the analysis of 50 urban
areas through the use of models and other analytical devices. The results
of this analytical activity were to provide base-line estimates from which
the nationwide characterization of pollutional loads and impacts, and the
costs of alternative control strategies could be developed. This section ad-
dresses the basic assumptions and methods employed to prepare some of the data
desirable for use of models and other analytical tools in this application.
Runoff quality and quantity analysis require data concerning features
such as lengths of steets and roads, population density, and types of land
use. The absence of such data has hindered the use of a modelling as only
general approximations could be used or considerable site specific data
gathered.
The data developed by the APWA presented in this section is based upon
a detailed analysis of 50 urban areas. Such a broad base of information should
be particularly helpful in adjusting models where site specific data is not
available and should encourage the development of models which more accurately
relate to land use and population density considerations.
The estimation of runoff quality by existing models depend upon the as-
sumption that pollutants accumulate over time on street surfaces. Models do
not accommodate accumulation of pollutants on non-street impervious areas as
outlined in Section III. Nor do models provide for pollutant contributions
from pervious urban areas for runoff events when these contributions from pervi-
ous urban areas for runoff events when these contributions may be expected to
occur. The basic assumption of street surface accumulation would seem to best
apply in well developed urban environments where drainage patterns are con-
sistent with street networks and impervious surfaces may be expected to entrap
many of the pollutional products of the area. In an urban setting, basic model-
ling philosophies hypothesize that the quality of urban runoff may be estimated
from runoff quantity computations based on given hydrologic and physical basic
characteristics; the computed transport of the potential pollutants contained in
accumulated street litter by the runoff; and the calculation of the related pol-
lutional loading based on its relationship to the transported solids. The fore-
going assumes, of course, that the mechanisms of runoff solids transport and the
pollutant-to-solid estimation processes within the model are accurate representa-
tions of the real physical processes involved.
181
-------
As the modelling effort for this study was directed to an evaluation of
50 urban areas, certain assumptions were made to accommodate its operation on
this relative scale. Some of these assumptions are as follows;
• Urban areas may be assumed to be the Urbanized Areas as defined by
the Bureau of Census.
* Average daily street solids accumulations are assumed to be a
representative indication of the accumulation of many pollutants
within an urban area. It is further assumed that the STOBM model
will adequately estimate the total solids transported in a runoff
flow for a given event. As pollutant concentrations are estimated
directly with the solids so estimated, it is also assumed that only
those pollutants that bear some reasonable level of linear correla-
tion with solids can be estimated through the modelling process.
Those that do not, should not be estimated in the modelling effort.
* The distribution of urban land use may be characterized in terms
of population density, on the basis of central city land-use
characteristics taken with respect to the entire Urbanized Area.
This assumption originates in the fact that little comparable
land-use-data could be found for full urbanized areas.
• Estimates of imperviousness and specific curb length, in terms
of unit of curb length per unit area, may be made through their
relationship with population density.
It is apparent that the assumptions made must be carefully considered with
respect to the accuracy assigned to the results of this evaluation effort. The
mechanism proposed, however, is one that may be improved upon as better data
becomes available. On this basis, it represents a prototype assessment methodo-
logy that may afford even better results as knowledge of runoff phenomenon im-
proves .
URBAN AREAS
Urban areas in this study have been taken as the Urbanized Areas defined
by the Bureau of the Census of the U.S. Department of Commerce in the 1970
census. (81) A total of 252 urbanized areas were defined in 1970; they are
generally characterized as having:
• A central city or urban core of 50,000 or more inhabitants.
* Closely inhabited surroundings, consisting of incorporated places
of 100 housing units or more; and small unincorporated parcels with
population densities of 1,000 inhabitants per 2.59 km2(l mi2) or more.
* Other small unincorporated areas that may eliminate enclaves, square
up the geometry of the urbanized area or provide a linkage to other
enumeration districts fulfilling the overall criteria within 2.5 km
(1.5 mi) of the main body of the urbanized area. (82)
182
-------
The distribution of urbanized areas across the United States is shown in
Figure 52.
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Figure 53, Distribution of urbanized areas sample with respect to
water resource and USEPA regions.
Source: U.S. Watar Resources Council, "Coordination Director for Planning Studies and Reports,"
August 1971,(as amended).
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Figure 53 (cont'd)
USEPA
Region I
Region II
Region III
Region IV
Region V
KEY TO USEPA REGIONS, SAMPLE URBANIZED AREAS
Core City
Hartford
Portland
Boston
Providence
Albany
Wilmington
Richmond
Charleston
District of Columbia
Birmingham
Jacksonville
Miami
Atlanta
Lexington
Jackson
Raleigh
Columbia
Knoxville
Nashville
Indianapolis
Detroit
Minneapolis
St. Paul
Cleveland
Madison
Milwaukee
State
Connecticut
Maryland
Massachusetts
Rhode Island
New York
Delaware
Virginia
West Virginia
Alabama
Florida
Florida
Georgia
Kentucky
Mississippi
North Carolina
South Carolina
Tennessee
Tennessee
Indiana
Michigan
Minnesota
Minnesota
Ohio
Wisconsin
Wisconsin
Region VI
Region VIII
Region IX
Region X
Core City
Little Rock
Topeka
St. Louis
Lincoln
State
Arkansas
Kansas
Missouri
Nebraska
Denver Colorado
Great Falls Montana
Fargo-Moorhead North Dakota
Sioux Falls South Dakota
Salt Lake City Utah
Phoenix
Tuscon
Oakland
Sacramento
San Francisco
Reno
Arizona
Arizona
California
California
California
Nevada
Boise Idaho
Portland Oregon
Seattle-Everett Washington
The Water Resources Region represents the major basins within the United
States as defined by the U.S. Water Resources Council. (83) The populations
reflected in the sample of urbanized areas appears in Table 107.
TABLE 107.
POPULATION DISTRIBUTION OF THE
SAMPLE OF URBANIZED AREAS
Population
Range
50,000 < Pop. < 1 00,000
100,000 < Pop. < 250,000
250,000 < Pop. < 500,000
500,000 < Pop. < 1 ,000,000
1, 000,000 < Pop.
Number of
Urbanized Areas
7
12
11
7
13
185
-------
MAJOR URBAN RUNOFF CATCHMENTS
The major urban runoff drainage areas were determined for each of the
urbanized areas selected for detailed study. These drainage areas were defined
In terms of the major catchments or receiving waters draining each urbanized
area, as shown in Table 108. This table shows the major catchments identified,
and the percent of the urbanized area contributing to each. These catchment
areas have been used to provide a basis for determining many of the urban area
parameters necessary for the broader evaluation effort.
TABLE 108. URBANIZED AREA RUNOFF CATCHMENTS
1.
2.
3i.
b.
c.
4.
5*.
b.
c.
6.
7.
8.
9.
10.
11.
12.
13.
14«.
b.
c.
d.
IS.
16.
17.
18.
19.
20.
21.
22.
23*.
b.
24.
25.
26a.
b.
c.
27.
28,
29.
3O.
31.
32.
33.
34.
35.
36.
37.
38.
390.
b.
Urbanized Area
Albsny-Schonectady
Troy, N.Y.
Albuquerque, N.M.
Atlanta, Ga.
Baton Rouga, La.
Birmingham, Al.
Bolie, Id.
Boston, Ma.
Charleston, W. Va.
Cleveland, Oh.
Columbia, S.C.
Dallas, Tx.
Denver, Co.
Dot Momes, la.
Detroit, Mi.
El Paso, Tx.
Fargo— Moorehead, N.D.
Groat Falls, Mt.
Hartford, Ct.
Indianapolis, In.
Jackson, Ms.
Jacksonville, Fl.
Knoxville, Tn.
Lexington, Ky.
Lincoln, No.
Little Rock— North
Little Rock, Ar.
Madison, Wi.
Manchester, N.H.
Miami, FI.
Milwaukee, Wi.
MInn»apoIIs— St. Paul, Mn.
Monroe, La.
N«thvillB— Davidson, Tn.
Phoonlx, Az.
Portland, Me.
Portland, Or.
Provldanco— Pawtucket—
Warwick, R.I.
Raleigh, N.C.
Reno, Nv.
Richmond, Va.
Total
ac
96,640
72,960
25,430
63,250
189,720
54,400
32,350
39,790
71 ,860
18,860
424,960
39,680
413,440
65,920
431 ,360
187,520
69,760
75,170
9,030
146,130
327,750
76,160
15,360
14,080
83,840
243,840
46,080
224,640
55,040
17,050
8,550
33,280
60,800
10,620
15,250
18,290
24,960
165,760
292,480
461 ,440
26,600
220,160
248,320
35,840
1 70,880
156,160
45,440
24,320
24,580
S8.220
Area
ha
39,110
29,530
10,290
25,590
76,780
22,020
13,090
16,100
29,080
7,510
171,980
16,060
167,310
26,680
1 74,570
75,890
28,230
30,420
3,650
59.14O
132,640
3O.82O
6,220
5,700
33,930
98,680
18,650
90,910
22,270
6,910
3,450
13,470
24,600
4,300
6,170
7,400
10,100
67,080
118,360
186,740
10,360
89,100
100,490
14,500
69,150
63,20O
18,390
9,840
9,950
27,610
Percent of
Urbanized
Area
100
100
9
23
68
100
22
28
50
100
100
100
100
100
100
100
100
13
2
26
59
100
100
100
100
100
100
100
100
67
33
100
10O
24
34
42
100
100
100
100
100
100
100
100
100
100
100
100
26
74
Major Catchment
Hudson River
Rio Grande River
Flint River
South River
Chattahoochee River
Mississippi River
Village Creek
Valley Creek
Cahaba River
Boise River
Massachusetts Bay
Kanawha River
Lake Erie
Congaree River
Trinity River
South Plane River
Des Moines River
Lake St. Clair
Lake Erie
Clinton River
Detroit River
Rio Grande River
Red River
Missouri River
Connecticut River
White River
Pearl River
St. Johns River
Tennessee River
Elkhorn Creek System
Hick man Creek System
Salt Creek
Arkansas River
Lake Waubesa
Lake Monona
Lake Mendota
Merrimac River
Biscayne Bay/ Atlantic Ocean
Lake Michigan
Mississippi River
Ouachita River
Cumberland River
Salt River
Fore River/Portland Harbor
Williamette/Columbia Rivers
Providence River/
Narragansett Bay
Walnut Creek
Truckee River
Chickahorniny River
James River
186
-------
TABLE 108 (cont'd)
40.
41.
42,
43a,
b.
C-
44.
45.
46.
47.
4Sa.
b.
49.
50.
Urbanized Area
Sacramento, Ca.
Salt Lake City, Ut.
San Francisco— Oakland, Ca.
Seattle— Everett, Wa.
Sioux Falls, S.D.
St. Louis, Mo.
Topeka, Ks.
Tucson, Az.
Tulsa, Ok.
Washington, D.C.
Wilmington, De.
Total
ac
156,160
117,760
435,840
17,870
93,390
153,050
17,280
295,040
33,920
6 7.20O
63,480
61 ,704
316,300
7O.400
Area
ha
63,200
47,660
1 76,380
7,230
37,800
61 ,940
6,990
119,400
13,730
27,200
25,690
20,930
128,200
28,490
Percent of
Urbanized
Area
100
100
100
7
35
58
100
100
100
1OO
100
100
Major Catchment
Sacramento River
Great Salt Lake
San Francisco Bay /Pacific Ocean
tSammamish Lake
Lake Washington
Puget Sound
Big Sioux River
Mississippi River
Kansas River
Santa Cruz River
Verdigres Rivor
Arkansas River
Potomac River
Delaware River
URBAN PHYSICAL DEVELOPMENT AND DEMOGRAPHIC CHARACTERISTICS
There are few sources of standardized data,covering the physical develop-
ment characteristics of urbanized areas. The evaluation of urban runoff im-
pacts requires definition of some of these characteristics. Urban land use
patterns, the level of surface imperviousness, street density and improvement
standards, and other development-related parameters are all basic building
blocks within the evaluation process. While data on physical development
characteristics are generally available locally in individual jurisdictions,
the scope of this overall evaluation effort did not envision an on-site sur-
vey of prospective urbanized area modelling sites. Thus, other methods for
estimating these parameters were necessary.
The most important source of urban demographic data in the U.S. Bureau of
the Census. The 1970 Census provides a wealth of standardized information ac-
cumulated in a land-area classification system that is compatible with the
purposes of this evaluation effort. The choice of the "urbanized area" as a
basic unit for the definition of urban runoff contributions has already been
discussed. One additional unit of areal definition was also adopted for the
purposes of the overall evaluation effort—the census tract. These units of
area and demographic data accumulation were selected as the smallest manage-
able units of area to be used. By definition, census tracts are relatively
uniform, stable area units in terms of population characteristics, economic
status and living conditions; they generally average about 4,000 residents. (86)
187
-------
The estimation of urban physical development characteristics for the 50
study areas has been preapred from census tract area measurements and demo-
graphic data. The key demographic parameter employed for this purpose is gross
population density. (85) This parameter was used to characterize land use,
imperviousness, street density, street cleaning frequencies, and other model
input requirements.
The data source used to characterize urbanized areas in terms of their
respective population densities was made available through the National Plan-
ning Data Corporation. This data source provided census tract population, area
and related population densities. Additional data on land use were also pro-
vided for some land-use types. Land use will be discussed in more detail in
the following portions of this section.
Urbanized areas and drainage catchments were characterized through develop-
ment of population density profiles. These profiles were developed by identify-
ing and ranking census tracts in ascending order by gross population density.
The ranked census tracts so determined were grouped into five categories,
designated on the basis of area. These categories were arbitrarily chosen as
one, approximately one-third sized part, and for, approximately one-sixth parts
of the total catchment area. The one-third sized area category represents the
most sparsely populated census tracts within the catchment.
The results of the population density profiling process are shown in
Figures 54a thru 54g, for various population groups by section of the country.
These figures demonstrate the cumulative gross population densities reported
over each urbanized area, as fitted to a geometric regression line. As these
lines show, the overall gross population densities indicated at the 100 per-
cent level vary from those shown at other percentage levels for each urbanized
area. Variations may also be noted among the gross population density pro-
files reported for individual urbanized areas. The gross population density
profiles, thus, suggest the level of variation that exists in the demographic
and physical development characteristics of the urbanized areas selected for
detailed study. This data in a modified form was used in the cost assessment
reported in Volume II,
188
-------
20.
Denver
Portland, Or.
Seattle
Lincoln
Sioux Falls
Topeka
Great Falls
Boise
Equation
41.9x-°-M
y = 40.2 x ~°'53
y = 36.2 x -°-51
y = 35.6 x -°'50
y = 26.7 x ~0>46
= 24.5x-°-46
y=22.8x-°'37
y = 15.2 x ~°'31
100 90
20 10
Average Percent of Urbanized Area
Figure 54a. Population density profiles for urbanized areas—Pacific Northwest—Missouri.
20
e
o
t/t
&
| 10
Z Q
UJ
Q
Z 8
O
? 6
Urbanized
Area
San Francisco-
Oakland
Sacramento
Equation
y=101.Sx
y = 31.0x
-0.67
-0.50
J I
J_
I
J
100 90 80 70 60 50
40
30
20 10
Average Percent of Urbanized Area
Figure 54b. Population density profiles for urbanized areas—California.
189
-------
El Paso
Phoenix
Dallas
Salt Lake City
Tucson
Reno
Albuquerque
10
Equation
y = 45.9 x -°'58
y = 36.4x-°-58
y = 43.8 x ~°-66
y = 36.2 x -°'54
y = 22.4 x -°'47
y = 25.3 x -°-47
y = 24.8 x
-0.44
40 30 20
Average Percent of Urbanized Area
Figure 54c. Population density profile for urbanized areas—Arkansas—Lower Colorado
Upper Colorado—Great Basin—Rio Grande—Texas Gulf.
1
Urbanized
Area
Equation
Miami
Baton Rouge
Jackson
Atlanta
Birmingham
Columbia
Knoxville
Raleigh
Jacksonville
Little Rock
Monroe
30 20 10
Average Percent of Urbanized Area
: 54d. Population density profiles for urbanized areas—South Atlantic Gulf-Upper Mississippi.
190
y =
y =
y =
y =
y =
y-
Y =
y =
y =
y =
v-
50.6
29.9
28.6
23.4
21.2
20.1
20.6
21.6
31.2
12.6
12.4
x-0.48
x-0.47
x-0.48
x-0.48
x-0.43
x-0.43
x-0.45
x-0.48
x-0.65
x-0.33
x-0.32
-------
20
10
9
8
7
2 6
ill
Q
I 5
Q.
O
Q.
2
100
Equation
y = 66.4 x
y = 56.3 x
y = 38.8 x
y = 35.7 x
y = 38.6 x
y = 45.2 x
-0.54
-0.61
-0.50
-0.44
-0.55
-0.64
32.4x"°-53
y = 27.2 x
-0.65
90 80 70 60 50 40
Figure 54e. Population density profiles for urbanized areas—Mid Atlantic—Ohio.
30 ^0 10
Average Percent of Urbanized Area
20-
Urbanized
Area
8
Equation
Detroit
St Louis
Cleveland
Madison
y = 58.6x-°'57
y = 58.9x-°-55
y = 85.2x-°-72
y = 44.6x-°-55
Minneapolis-St Paul y = 49.0 x~°'83
Fargo y = 23.7 x"0'38
Des Moines y = 30.0 x~°'52
Milwaukee. y = 13.0 x~°'35
100 90 80 70 60 50 40 30 20 10
Average Percent of Urbanized Area
Figure 54f. Population density profiles for urbanized areas—Great Lakes—Upper Mississippi.
191
-------
20
10
u
Jf
0
S 8
D.
ui 6
Q
Z
o
Is
a.
9 4
Boston
Hartford
Providence
Manchester
Portland, Me.
y = 92.2 x -°-71
y = 53.9 x -°-57
y = 54.3 x -°-60
y = 54.9 x -°-57
y = 43.4x-°-68
j_
100 90 80 70 60
50 40 30 20 10
Average Percent of Urbanized Area
Figure 54g. Population density profiles for urbanized areas—New England
LAND USE CHARACTERIZATION
A key ingredient of the evaluation effort is urban land use. Pollution
potentials, physical development characteristics, and public works operations
practices have been characterized in terms of urban land use. Land use,
however, is seldom defined for entire urbanized areas—particularly where
portions of an urbanized area may fall into different political jurisdictions.
As stated, one of the sources of land-use data employed in this project
was the population density files created by the National Planning Data
Corporation. These files were developed from 1970 census data and the map-
ping available through the Metropolitan Map Series available from the U.S.
Department of Commerce. These maps were electronically planimetered and the
192
-------
and the areas determined were grouped into four major categories: Total
census tract areas; water surface areas; apparent non-residential land-use
areas; and areas containing special institutional population concentrations. (86)
Data from 48 of the 106 cities reported representing central cities as
opposed to suburban communities and were complete enough to use in the develop-
ment of a land-use estimating method. A regression analysis compared gross
land utilization rates determined from mid-1960fs land-use area data with
overall population density determined from the reported cities. The results
are represented in Figure 55.
0.11
y = Residential LU = 0.1007 (0.9366)
y = Commercial LU =
0.0171
„ 0.3413
y = Industrial LU = 0.0110 (0.9607)"
r = 0,44
y = Park LU = 0.0157 (0.9426)*
r = 0.53
0.01-
20
30 40 50 60 70 80
X, POPULATION DENSITY, persons/acre
90
100
110
Figure 55. Land utilitzation rates for various cumulative
population densities — nationwide.
193
-------
The figure shows residential, industrial, commercial and park land utiliza-
tion rates from the data uncovered on a nationwide basis. Relatively low cor-
relations were indicated for commerical, park and industrial land uses. Regional
analysis of land-use data was performed on tha available central city informa-
tion for the water resource regions shown in Figure 56. On this basis, a
theoretical construct of land use for each of the Water Resources Regions or
aggregates of regions where data proved limited was created for land use
estimating purposes. The results of this analysis is plotted in Figures 57
thru 60. Thus, two alternatives are posed for land use estimating within
urbanized areas — nationally and more specifically for water resource regions
where possible.
Generally, this information shows that better correlations can be expected
for data sets representing a broad span of population density. On a regional
basis, better comparisons would have been possible with larger data sets for
each region that represented a broad range of population density. Insofar as
better or more inclusive data was not uncovered, the functions developed on
the basis of the regional analysis of 48 cities were used as estimators of
land use in the nationwide analysis.
The total census tract areas and water surface areas are considered the
most accurate values available. The commerical and industrial land use areas
contained within the files are viewed as low values because map measurements
for these areas were performed on 1:24,000 scale maps and, as such, were limited
to obvious or large-size parcels in these use categories. The residential
land-use areas from the data files also appeared less accurate. Residential
land-use areas are residual areas not otherwise classified in other use cate-
gories. As such, they are generally considered as high values since they also
contain the land areas that may be suitable for future residential development. (86)
The National Data Planning Corporation data files were used to define
land use in those parts of urban catchments where population densities were high.
It was assumed that high population densities indicate relatively complete
development and that with complete development, the data files would provide
relatively accurate information.
The basic land-use estimating methods employed in the study were derived
from data developed in past work by Bartholomew (87) and Manvel. (88) The land
used data identified from these sources did not prove as up-to-date as might
be desired. Of the two, the latter source provided more current data on land
use as of the middle 1960's. A total of 106 cities was surveyed and all
were of 100,000 population or more. All of the cities reported were central
cities or cities representing some part of an urbanized area.
A more detailed analysis of how the above methods were used is presented
in Volume II, Section 3, Description of the Urbanized Areas.
194
-------
VO
U1
J 7--ci
FIGURE 56, LAND-USE REGIONS
-------
I
I
£
CO
1
Pacific Northwest — Missouri y = 0.1098 x °-1704
0.2964 0.12
0.2470 0.10
0.1976 0.08
0.1482 0.06
Arkansas — White — Red — Lower Colorado
Upper Colorado — Great Basin y = (0.4582) x ~0-'704
S. Atlantic Gulf — Lower Mississippi y = 0.1125 (0.9401 )x
.California y = 0.0845 (0.952)x
Great Lakes — Uppar Mississippi y = 0.1259 (0.9227*
Mid Atlantic — Ohio y = 0.0959 (0.9383!*
New England y a 0.06 — 0.001 Sx
0.0988 0.04
0.0494 0.02
40 50 60 70 80 90 100
x Population Density — Persons per Acre
Figure 58. Commercial land utilization rates for various water resources regions.
0.0988 0.04-
0.0741 0.03
0.0494 0.02 -
0.0247 0.01
N«w England v = 0.0078 + O.OO07X
Mid Atlantic — Ohio y = 0.0188 (0.926)
'Pacific Northwest — Missouri y = 0.0108 (0.946)x
Great Lakes — Upper Mississippi y = 0.0168 x '•3323
f
South Atlantic Gulf — Lower Mississippi
V = O.O213 X
-O.4374
.3968
T.x..Gu,fv- o.oossxO-3763 10 20 30 40 50 60 70 80 90 100
x Population Density — Persons Per Acre
Figure 57. Residential land utilization rates for various water resources regions.
196
-------
0.0741 0.03
0.0494 0.02 •
0.0247 0.01
-Texas Gulf y = 0.0517 (0.6242)x
-New England v = 0.0127 — O.OOOSx
California v = 0.0187 x ~°'538
I Great Lakes — Upper Mississippi y = 0.0358 x ~°'6782
• Mid Atlantic - Ohio y = 0.0151 (0.961 )x
,South Atlantic Gulf — Lower Mississippi y = 0.0132 (0.8933)x
, Arkansas — White — Red — Lower Colorado
Upper Colorado — Great Basin v = 0.0057 + 0.0012x
10 20 30 40 50 60 70 80 90
x Population density—persons/acre
Figure 59. Industrial land utilization rates for various water resources regions.
i
0.0741 0.03
0.0494 0.02
0.0147 0.01
.Arkansas — White — Red — Lower Colorado
Upper Colorado — Great Basin y = 0.035 — 0.0039x
• Mid Atlantic - Ohio y = 0.0235 (0.9108)x
New England y = 0.0236 — O.OOOSx
Pacific NW - Missouri y = 0.0336 (0.8479)
Texas Gulf y = 0.0122 — 0.0004x
Great Lakes — Upper Mississippi y = 0.0633 x
^» California y = 0.0155x
S. Atlantic Gulf — Lower Mississippi y = 0.0114(0.8975)'
-0.8013
-0.3433
10 20 30 40 50 60 70 80 90
x Population density—persons/acre
Figure 60. Park land utilization rates for various water resources regions.
197
-------
RUNOFF QUALITY CHARACTERIZATION
The estimation of runoff quality by the use of the STORM model depends
upon the accumulation of pollutants within a drainage basin over time. The
urban street cross-section is considered a logical repository for pollutants
carried by wind and water from their places of origin, and a depository for
the pollutant products of street and related activities. Based on this assump-
tion, the model estimates runoff quality in terms of the amounts of pollutants
that will accumulate in urban streets and be washed off during a rainfall
event.
On this basis, the model deals with runoff pollutants in terms of their
relationship to urban street litter. Proceeding from the average daily
accumulations of litter, the model estimates the quantity of soluble pollutants
picked up by a give street runoff. (80) For the purposes of this evaluation,
it was assumed that STORM will adequately estimate the quantity of solids re-
moved by a particular rainfall event. The materials so transported were
assumed to constitute the total solids load contributed by the street litter.
Pollutant loads were estimated on the basis of their relationship to the
amounts of total solids so removed.
Three studies funded by the USEPA represent the source of the majority
of the existing information on dally street litter accumulation and street
litter pollutional potentials. The first of these was performed by the
American Public Works Association in the City of Chicago. (15) The URS
Research Company performed another study that sampled street litter in a
number of cities across the country. (43) The remaining study was completed
by Biospherics, Incorporated based on street litter samples collected in
Washington, D.C. (6)
Some of the findings of the sampling programs conducted for these studies
are summarized In Table 109. The data shown reflects mean values for all
reported data, regardless of the method of sampling or other differences in
samples. These values are, therefore, somewhat different from those reported
in other sections of this report; but were used as beginning values for
modelling computations. Statistical comparisons of the means among land use
types and overall estimates indicated that average values for residential,
industrial and park land uses were significant enough to differentiate these
values from the overall mean, while the value for commercial land use was not.
Thus, the mean value for commercial data was taken as the estimated population
mean. Similarly, comparisons of daily street solids were prepared on a regional
basis. The results of these comparisons are shown in Table 110. These data
are inconsistent with those cited In Section III in so far as they are early
estimates of these values.
198
-------
TABLE 109. AVERAGE DAILY ACCUMULATIONS OF STREET SOLIDS
Land Use
APWAa
Ib/curb-mi/day
(kg/curb-km/clay)
URS Research Co.b
Ib/curb-mi/day
(kg/cu rb-km/day)
Biospherics, Inc.0
Ib/curb-mi/day
(kg/curb-km/day)
Overall
Ib/curb-mi/day
(kg/curb-km/day)
Residential
Mean
Range
80
(23)
1i-153
(5-43)
153
229
(64)
3-2,700
(0.8-761)
42
71
(20)
7-378
(2-107)
58
103
(29)
3-2,700
(0.8-761)
253
Commercial
Mean
Range
n
181
(51)
71-326
(20-92)
126
46
(13)
3-260
(0.8-73)
17
126
(36)
17-712
(4-201)
22
160
(45)
3-712
(0.8-201)
165
Industrial
Mean
Ranp
n
325
(92)
283-536
(80-151)
55
292
(82)
4-1,850
(1-521)
20
316
(89)
4-1,850
(1-521)
75
All Uses
Mean
Range
158
(45)
19-536
(5-151)
334
206
(58)
3-2,700
(0.8-761)
79
86
(24)
7-712
(2-201)
80
154
(43)
3-2,700
(0.8-761)
493
Sourcss; aAmerican Public Works Association, "Watar Pollution Aspects of Urban Runoff." USEPA Report No.
1103QDNS01/69 (NTIS No. PB 215 532), January, 1969.
Sartor, J.O., and G.B. Boyd, "Water Pollution Aspects of Street Surface Contaminants," USEPA Report No.
EPA-R2-72-031 (NTIS No. PB 214408), November, 1972.
cShahean, D.G., "Contributions of Urban Roadway Usage to Water Pollution," USEPA Report No. EPA-600/
2-75-004 JNTIS No. PB 245 854), April, 1975,
199
-------
TABLE 110. REGIONAL DAILY STREET SOLIDS ACCUMULATION VALUES
Residential Commercial Industrial Open Space
Water Rtiource
Region
Ark«nsas-White-Red
Lower Colorado
Mean
Range
a
n
Great Lakes
Mean
Range
a
n
MM Atlantic-Ohio
Mean
Ranp
a
n
California
Mean
Range
a
n
S. Atlantic-Gulf
Mean
Range
a
n
Pacific Northwest
Mean
Range
a
n
T«xa$ Gulf
Mean
Range
a
n
New England
Mean
Range
a
n
Nationwide
Mean
Range
a
n
Ib/curb-mi/day
(kg/curb- km/day)
C1I
51 (14)
6-238 (2-87)
12
84(24)
19-770(5-217)
157
0
0
(2)
178(50)
31-2i5 (9-83)
4
(i)
30 {8)
12-15 (3-13)
4
0
0
103 (29)
3-2.700 SO.8-761
205 (58)
253
Ib/curb-mi/day Ib/curb-mi/day
(kg/curb-km/day) (kg/curb-Ian/day)
(1) (t)
21 (6! 58 (16)
3-53(0.8-15) 4-130(1-37)
20.4 (6) 54 (15)
0
181 (51)
6-326 (2-92)
128
(2) 0
57 (16)
4-168(1-47)
77 (22)
4 4
111
18 (5) 104 !29)
3-26 (0.8-7) 19-204 (5-57)
4
0 0
0 0
0 0
0 0
~-
154(43} 316(89)
4-1,850(1-521)
207.3 (58) 272.6 (77)
493 75
Ib/curb-mi/day
(kg/curb-km/day)
0
0
0
0
0
0
0
0
O " standard deviation
n • number of observations
!1) denotes a difference from the nationwide estimate of the population mean at a level of
significance of 0.1.
(2) denotes a difference from the nationwide estimate of the population mean at a level of
significance of from 0.1 to 0.2
Source: American Public Works Association, "Water Pollution Aspects of Urban Runoff," USEPA
Report No. 11030DNSO1/B9 (NTIS No. PB 215 532), January, 1969.
Sartor, J.D., and G.B. Boyd, "Water Pollution Aspects of Street Surface Contaminants,"
USEPA Report No. 72-031 (NTIS No. PB 214408), November, 1972.
Shaheen, D.G. "Contributions of Urban Roadway Usage to Water Pollution," USEPA
Report No, EPA-60O/2-7S-OO4 (NTIS No. PB 245 854), April, 1975.
200
-------
On the basis of these street solids accumulation values, population
density values and land utilization rates previously defined, composite
accumulation values were determined for various population densities. The
composite values were computed from the general equation:
where:
s _ P(2 SL
R
So Ro
(21)
Ro
S - Composite daily solids accumulation
P = Population density
Sj - Daily solids accumulation for each given land use
LU, - Land utilization rate for each given land use
Li
TL.
Ju
Relative road density expected within each given land use
So = Daily solids accumulation for undeveloped land
Ro = Relative road density expected within undeveloped areas
All of the elements contained within the compositing expression may be
defined from the foregoing with the exception of the relative road density
expected within each given land use. Some values for relative road density
are shown in Table 111.
TABLE 111. RELATIVE ROAD DENSITY VALUES
Land Use
Average Specific
Curb Length
mi/ac km/ha
Range of Specific
Curb Length
mi/ac
km/ha
Residential
Commercial
Industrial
Park
Undeveloped
All land uses
0.076
0
0
0
0
0
.082
.041
.042
.016
.069
0.302
0.
0.
0,
0,
0,
,326
,163
,167
.064
,274
0.051
0.054
0.033
—
—
0.053
-0
-0
-0
—
—
-0
.115
.127
.064
,127
0.
0.
0.
0
,203
.215
.131
—
—
.131
- 0.457
-0
-0
—
—
-0
.505
.245
.505
Source:
AVCO Economic Systems Corporation, "Storm Water Pollution From Urban Land Activity,"
USEPA Report No. 1 1 034 F K L/07-70 (NTIS No. PB 195 281), July, 1970.
201
-------
The resulting composite street solids accumulation values related to
population density and land use for all but park and undeveloped area
contributions are shown in Figure 61. These values are dependent upon the
assumptions that national land utilization factors are applicable as esti-
mates of land use. Related estimations of suspended solids and BOD 5 are
also shown for those street surface contributions for the indicated land
uses. Values for park and undeveloped areas were found to be unavailable
from existing data sources. Assumed values for these land values were
taken as 13.6 kg/curb-km/day (16 Ib/curb-mi/day) for the purposes of the
modelling analysis.
Ill
>
O
24.3 901—
21.6 80
O 19.0 70
ss
O £ 16.3 60
D O 13.6 50
g
-------
Statistical comparisons of the pollutant concentrations for individual
land uses with overall concentrations for the pollutant data sets selected
in the array of concentrations is shown in Table 112, This table shows
overall concentrations of the various pollutants, as well as those concentra-
tions specific to given land uses. These specific concentrations are shown
where a difference of means at a level of significance of at least 0.2 is
indicated.
The values for BODj. are given in both rag/kg and mg/1 formats due to
their low correlation with solids. Organic nitrogen is also reported as
mg/1 since its correlation to total solids (discharge) proved to be
negligible. The values reported for asbestos, cadmium, chromium, copper,
iron, lead, manganese, nickel, strontium and zinc are all derived from
street surface accumulation data in view of the fact that virtually no
information was available from the discharge data for comparative purposes.
As such, these values may prove somewhat low if the relative comparisons for
the other pollutants are also applicable to metals.
TABLE 112. RELATIVE POLLUTANT LOADS
Open
Pollutant
Suspended
Solids
Mean
Range
0
n
Volatile
Solids
Mean
Ranp
0
n
BODS
Mean
Range
0
n
BODS
Mean
Range
a
n
COD
Mean
Range
0
n
Residential
mg/kg
0
0
(1)
29,840
7,890-66,400
15,330
18
0
(2)
207,600
57,000-509,000
125,000
14
Commercial industrial
mg/kg mg/kg
0 0
0 0
(1) 0
83,600
25,500-175,000
51,970
10
0 0
(2) 0
393,200
101,000-690,900
200,200
11
Space Overall
mg/kg mg/kg
0
576,000
154,800-915,200
192,100
42
0
332,300
108,400-652,000
142,110
22
0
k
53,180
5,800-250,000
52,610
52
0
24 mg/i
3-126mg/I
24.5
43
0
288,700
49,100-880,600
190,700
41
203
-------
TABLET 12 (cont'd)
Residential
Pollutant mg/kg
TOC 0
Mean
Range
a
n
HO3 0
Mean
Range
a
n
Organic N 0
Mean
Range
a
n
Sol, Ortho-
Phosphate 0
Mean
Range
CT
n
Total PO4 0
Mean
Range
a
n
Chlorides 0
Mean
Range
a
n *
Asbestos 0
Mean
Range
a
n
Cadmium (1)
Mean 3
Range 0-8.8
o 2.4
n 44
Open
Commercial Industrial Space Overall
mg/kg mg/kg mg/kg mg/kg
0 00
32 mg/l
15-48 mg/l
9.5 mg/l
17
0 00
0.8 mg/l
0.1 -0.5 mg/l
0.5 mg/l
9
0 00
1.32 mg/l
0.39-3.5 mg/l
0.96
23
(1) 0 0
3,150 1,860
170-6,670 170-7,100
2,270 1,833
10 40
0 00
1.3 mg/l
0.3-0.5 mg/l
1.1 9 mg/l
14
0 00
18.8 mg/l
2-74 mg/l
20.7 mg/l
19
0 00
12.3x10* fibers/kg
2.4x1 06 -13.9x10*
fibers/kg
7.1x10* fibers/kg
6
0 00
3
0-25
3.5
78
204
-------
TABLE 112{cont'd)
Pollutant
Chromium
Mean
Range
a
n
Copper
Mean
Range
a
n
Iron
Mean
Range
a
n
Lead
Mean
Range
a
n
Maganese
Mean
Range
o
n
Nickel
Mean
Range
a
n
Strontium
Mean
Range
a
n
Zinc
Mean
Range
a
n •
T. Coli
Mean
F. Coli
Mean
Notes: (1)
(2)
Al!
Residential
mg/kg
(1)
183
49-390
77
48
0
0
(2)
1,580
220-5,700
1,230
43
0
0
0
0
0
0
denotes a difference
denotes a difference
Commercial
mg/kg
0
162
25-810
195
15
0
(1)
3,000
0-10,000
2,460
17
0
(2)
52
6-170
50
17
0
515
190-1,100
241
17
0
0
from the overall estimate
from the overall estimate
Industrial
mg/kg
(1)
284
74-760
168
17
0
(2)
26,200
8,100-72,000
14,490
21
0
(1)
540
180-1,600
880
20
0
0
0
0
0
of population mean at
of population mean at
Open
Space Overall
tug/kg mg/kg
0
213
49-760
113
82
0
117
33-810
95
78
0
22,860
5,000-72,000
11,300
81
0
2,080
0-10,000
1,930
81
0
400
100-1,600
206
80
0
36
0-170
37
82
0
21
0-110
20
80
0
390
110-1,100
200
82
0
20.7x1 0s /kg
0
2.9x106/kg
a level of significance of 0.1 or less.
a level of significance of from O.2 to 0.1
units are in mg/kg unless otherwise noted.
205
-------
CHARACTERIZATION OF STREET CLEANING OPERATIONS AND OTHER PHYSICAL DEVELOP-
MENT FACTORS
The characterization of street cleaning operations, imperviousness and
curb length per unit area also were important inputs to the modelling effort.
Street cleaning operations involve street cleaning frequency or the period
between cleanings in days, and street cleaning efficiency or the percent of
street litter picked up by cleaning operations.
The basic source of street cleaning data was from the 1973 APWA Survey
of Street Cleaning, Catch Basin Cleaning and Snow and Ice Removal Practice
the results of which were given in Table 85.
Street cleaning effectiveness has been found to vary with the particle
size distribution of street surface accumulations; accumulation loadings
and the loading distribution on the street surface; the street surface
type and condition; the type of cleaning equipment used and its characteris-
tics; number of passes of the cleaning equipment; and the equipment operator's
ability. Overall sweeping effectiveness for conventional street sweepers
has been found to be about 50 percent. (43) Improved removal effectiveness
has been found for vacuumized sweepers, but data for this equipment is not
generally available. A review of some of the data from the 1973 APWA Survey
of Street Cleaning, Catch Basin Cleaning and Snow and Ice Removal Practice,
however, indicates that of 363 respondent municipal jurisdictions, only 27
had purchased any vacuumized equipment and then in only limited quantities.
As of that time, the relative impact of vacuum equipment on cleaning effective-
ness had not been felt to any great degree. It is, therefore, assumed that
the main effort in street cleaning operations is still being performed by
conventional street sweepers, although a trend to vacuumized equipment may
be underway.
Physical development relationships, such as imperviousness and specific
curb length, have been estimated from the functions indicated in Figures 62
and 63. These estimating curves were developed on the basis of the original
Washington, D.C. data on imperviousness, curb length and population density,
first developed by Graham, Costello and Malion. (89) This information was
extended by the addition of reported values from other cities in the nation
and regression lines were developed. The distribution of the cities from
which data were evolved for this analysis were: Durham, N.C.; Roanoke, Va.;
District of Columbia; Bucyrus, Ohio; Milwaukee, Wis.; Tulsa, Ok.; and San
Francisco, Calif.
Other Data Requirements
The foregoing discussions have identified estimates and estimating
methods for a number of the data requirements necessary for the analysis
of the 50 urbanized areas selected. In general, these have covered urban
development and runoff quality data needs. Other data needs, such as
pollution control and abatement data, are developed in other sections of
the report. Rainfall data have been obtained from the U.S. Weather
Service. Control and abatement information is developed in Volume II of
this report.
206
-------
100
90
80-
70
I60
K
I 50'
40
30
20
Impennoutness = 104,95-81.27 (0.974)PD
where PD it the population density (persons/act
10 20 30 40 50 60 70 80 90 100 pop/ac
25 50 75 100 125 150 175 200 225 250 pop/ha
GROSS POPULATION DENSITY
Figure 62. Imperviousness vs. population/density — nationwide, 1974.
x
o
m
IT
3
o
ft/ac m/h«
400 122.
350 107.
300 91.4.
2SO 76,2 -
200
150 46
100
50
30.5
15.2
Curb Length = 413.11-1352.66) <0.839)PD
whore PD is population (tensity (personi/ae)
30 40 50 60 70 80 90 100 pop/ac
75 100 125 150 175 200 225 250 pop/ha
GROSS POPULATION DENSITY
Figure 63. Specific curb length vs. population density
nationwide, 1974.
207
-------
SECTION V
RECEIVING WATER IMPACTS OF URBAN RUNOFF
Receiving waters are those water bodies—lakes, streams, estuaries, bays,
and oceans—that are the recipients of wastewater flows. The value of these
water resources is beyond realistic assessment. The degradation of their
quality influences their use as water supplies for home, farm, or factory and
for aesthetic and recreational enjoyment. Quality impairment may also upset
and even destroy the diverse and complex biological systems inhabiting and
dependent upon these water bodies.
Water quality impairment is most often the product of pollutional con-
taminants in wastewater flows. Municipal and industrial wastewaters, and the
introduction of contaminants through the direct and indirect contributions of
runoff, all add to the problems of maintaining water quality. Initiatives
undertaken to alleviate the pollution associated with municipal and industrial
wastewater effluents have lightened the burden of insuring receiving water
quality.
The pollutional problems associated with runoff, however, remain to be
resolved. It has been estimated that from 40 to 80 percent of the annual total
of oxygen-demanding contaminants are contributed from sewer overflows, storm-
sewers, uncontrolled runoff and bypasses in urban areas where municipal and
industrial wastewater effluents have received secondary treatment. (90)
Some of the toxic contaminants yielded in runoff are also significant. A
modestly sized city may discharge from 45.5 to 114 MT/yr (50 to 125 t/yr)
of lead and from 2.7 to 13.6 MT/yr (3 to 15 t/yr) of mercury annually in its
runoff. Similarly, from 70 to 90 percent of the annual suspended solids load-
ing may be attributed to urban runoff. (90) Most significantly, these con-
taminants may occur as shock loadings on the receiving water as a result of
individual rainfall events,
The net effects of these and other wastewater contaminants on the sensitive
balance of a receiving water may be disastrous. The introduction of solids,
oxygen consuming contaminants, nutrients and toxic materials that exceed a
water body's natural assimilation capacity, can provide major changes in its
character. Combined sewer overflow discharges from Bucyrus, Ohio to the San-
dusky River resulted in distinct symptoms of gross pollution. Sections of the
river were devoid of dissolved oxygen; sludge deposits and extensive algal
growth were apparent; and in some of its reaches, the river was completely
devoid of life. (57) Similarly, frequent fish kills in Sugar Creek in Illinois
were traced to combined sewer overflows from Springfield following rainstorms. (91)
208
-------
Other, more subtle effects on receiving water quality may also be dis-
cerned. Certain organic chemicals used as insecticides and herbicides, when
introduced into a receiving body, may accumulate in various fish and snail
species in concentrations higher than those found in the water itself. (92)
Similarly, the methylation of mercury and its accumulation in fish is detri-
mental to natural stream fauna and the predators that may rely upon this
source of food. (93)
Thus, the relative impacts of wastewater flows may bear significantly
on receiving water quality, with a resulting impairment of its value. Al-
though all of the processes involved are not clearly understood, some in-
sights are possible through a summary of some of the past efforts under-
taken to study the phenomena involved.
RECEIVING WATER ASSIMILATION CAPACITY (94)
The impacts resulting from the addition of wastewater contaminants to a
receiving water are largely determined by the assimilative capacities of the
water body. Assimilation refers to the transformation and incorporation of
these materials by the aquatic system. Assimilative capacity is determined
by the interaction of complex physical, chemical, and biological aquatic sub-
systems. A number of factors, such as the velocity and volume of flow, water
body bottom contours, rate of water exchange, currents, depth of flow, light
penetration, temperature, pH, hardness, alkalinity and nutrients, all contri-
bute to relative assimilation capacity. The introduction of contaminants to
a receiving water in amounts that exceed the ability of the water body to
recover, or the addition of toxic materials or those that may accumulate to
undesirable levels, will result in the impairment of receiving water quality.
The addition of a given pollutant will tend, over time, to reach a steady
state condition within a water body that is determined by its rate of addition,
the rate of its removal or dilution by circulation, and the rate of its decom-
position or removal by biological, chemical, or physical processes. A straight-
forward conceptual model of the processes involved is shown in Figure 64 •
It is apparent that receiving water capacity is determined largely by
the nature and characteristics of the water body. Dilution in a stream may be
determined from the rate of contaminant addition and the stream's volume of
flow. This does not hold for lakes and estuaries where long average retention
times may allow the accumulation of conventional contaminants. Some representa-
tive estimates for average retention times are shown in Table 113 . The dilu-
tion and circulation characteristics of receiving waters are most important for
conventional pollutants—solids, heavy metals, etc. Other non-persistent con-
taminants, such as decomposable organic, are also subject to the rate of their
decomposition as part of the definition of their relative impact. Some of
the products of this decomposition are persistent contaminants that may also
accumulate to produce long-term water quality impacts.
209
-------
Pollutant
Diluted and
Dispersed By
Turbulent
Mixing
Marine
Environment
Ocean
Currents
Exchange
With
Atmosphere
Transported
By
Ocean
Currents
Concentrated
By
Uptake
By
Fish
Biological
Processes
1
Uptake
By Phyto-
plankton
V
Uptake
By
Seaweeds
Invertebrate
Brenthos
\
Sorption
Zooplankton
\7
Fish and
Mammals
Migrating
Organisms
Gravity
(Sinking)
Chemical and
Physical
Processes
Precipitation
Accumulation
on the Bottom
Ion
Exchange
Figure 64. Processes that determine the fate and distribution of a pollutant
added to the marine environment.
Sourc*: Kajcham, B.H., "Man's Resources in the Marine Ecology, " Pollution and Marine Ecology,
IntarsciflncB Publishers, New York, 1967.
210
-------
TABLE 113. AVERAGE DETENTION TIMES AND HALF-
IN THE GREAT LAKES AND IN VARIOUS ESTUARIES
LIVES FOR RIVER WATER
AND COASTAL REGIONS
Lake Superior
Lake Michigan
Lake Huron
Lake Erie
Lake Ontario
Capes Cod to Hatteras
to 1,000 ft contour
New York Bight
Bay of Fundy
Delaware Bay
high flow
Raritan Bay
high flow
Long Island Sound
Surface
Area
mi2
31,820
22,420
23,010
9,930
7,520
29,000
483—662
3,300
—
45
930
km2
82,870
58,390
59,920
25,860
19,580
75,520
1,260-1,720
8,590
—
120
2,420
Theoretical
Mean Retention
Time
183 years
100 years
30 years
2. 8 years
8 years
1 .6 - 2.0 years
6-7.4 days
76 days
48 -126 days
15-30 days
36 days
Half Life
128 years
69 years
21 years
1 .9 years
5.6 years
1.1 — 1 .4 years
4.1 - 5.05 days
52 days
33 - 87 days
10 - 21 days
25 days
Sources: Beaton, A.M., "Changes In the Environment and Biota of tha Great Lakes," Entmphication: Causes, Consequences,
Correctives, National Academy of Sclencas, Washington, D.C., 1969.
Ketchum, B.H., and D, J. Keen, "The Exchanges of Fresh and Salt Waters in the Bay of Fundy and in Passamaquoddy
Bay," Journal of Fisheries Research Board of Canada, 10(3): 97— 124.
Ketchum, 8.H., and D.J. Keen, "The Accumulation of River Water Over the Continental Shelf Between Cape Code and
Chesapeak Bay," Marine Biology and Oceanography, London, pp. 346-357.
Ketchum, B.H., "The Flushing of Tidal Estuaries," Sewage and Industrial Wastes, 23 (2): 198-208.
Riley, G.A., "Hydrography of the Long Island and Block Island Sounds," Bulletin Bingham Oceanographic Collection,
Yale University, 8: 5-39.
211
-------
Thus, the Impacts of wastewater contaminants on a receiving water may be
characterized in terms of the following factors:
» The makeup of the contaminants
* The degree of discharge quality enhancement achieved
through treatment
• The amounts of pollutants entering a receiving water
• The response of the ecosystem
These factors suggest that impact assessment and reasonable receiving
water quality requirements should be the product of the detailed analysis of
each receiving water body performed in the light of real data and realistic
objectives. Historically, however, water quality criteria have taken a
number of forms. The major form of criteria has been an array of allowable
limits organized on the basis of specific public health and other needs,
associated with subsequent beneficial water uses. Select general water
quality criteria developed on this basis are shown in Table 114. These types
of criteria are extremely useful, insofar as they may be related to the
deleterious effects of using poor quality receiving waters for specified
purposes. They are also limiting, however, because they are overall criteria
and may not reflect the impact of contamination on receiving waters of varying
characteristics and sensitivities. These impacts may be determined only
through the type of analysis previously suggested.
Other approaches to the definition of water quality criteria have dealt
with one or more of the impact factors outlined above. These include effluent
criteria, implied standards of treatment, and, in some cases, effluent limita-
tions imposed as a result of existing or potentially undesirable conditions
with a receiving water.
212
-------
TABLE 114. WATER QUALITY CRITERIA FOR VARIOUS
SUBSEQUENT BENEFICIAL USES
Intended Use
Quality
Limit
ABS (detergent) mg/l
Aluminum, mg/t
Ammonia— N, mg/l
Arsenic, mg/l
Barium, mg/l
Berylium, mg/l
Boron, mg/I
Cadmium, mg/l
Carbon Absorbable
Organ ics
Carbon Chloroform
extract mg/l
Carbon alcohol
extract mg/l-
Chlorides, mg/l
Chromium, mg/l
Coliform
Fecal/1 00 ml
Total/100 ml
Color, Standard
Cobalt Scale Units
Coblat, mg/l
Copper, mg/l
Cyanide, mg/l
Electrical Conductivity
# m h os/cm
Emulsified Oil and
Grease mg/l
Floatable Oil and
Grease mg/l
Fluorides, mg/l
50-54°F (10-12°C)
55"58°F(13-14°C)
59"64°F(15-18°C)
65-7 ff <19-22°C)
72-79°F (23-26°C)
80-9 1°F (27-33°C)
Iron, mg/l
Lead, mg/l
Lithuim, mg/l
Maganese, mg/l
Mercury, mg/l
Molybdenum, mg/l
Drinking
Water Livestock
Maximum Recommended
Permissible Maximum
Concentrations Concentration
0,8
5
0.5
0.5 0.2
1.0
—
5.0
0,01 50 mg/l
0.2
1.5
250
0.05 1.0
2.000
20,000
75
1.0
1.0 0.5
0,02
— —
0
0
2.4
2.2
2.0 2.0
1.8
1.6
1.4
0.3
0.05 0.1
— —
0.05 10 mg/l
0.002
— —
Irrigation
Limiting or
Recommended Maximum
Concentration
—
5
—
0.1
—
0.1
0.75
0.01
—
—
350
0.1
1,000
—
—
.05
0.2
—
2,250
—
—
1.0
5,0
5.0
2.5
0.2
0,2
0.01
Water Boating &
Contact Aesthetics
Limiting Limiting
Threshold Threshold
2.0 5.0
— —
— , —
— —
— —
—
— —
— —
—
— —
— —
— —
— —
— —
100 100
— —
— —
— —
— —
20 50
5 10
— —
— —
— —
— —
— —
— —
Note:
The foregoing values are a mix of most stringent limits as cited in the sources defined. It should be recognized that the values shoyvn
are from existing standards and do not reflect the "national interim primary regulations" or "secondary regulations" to b*
published by the USEPA under the Safe Drinking Water Act of 1974.
213
-------
TABLE 114 (continued)
Nitrata-N, mg/I
Nitrate-N, mg/I
Drinking
Water
Maximum
Permissible
Concentrations
10
1
Livestock
Recommended
Maximum
Concentration
—
Irrigation
Limiting or
Recommended Maximum
Concentration
—
Water
Contact
Limiting
Threshold
—
Boating &
Aesthetics
Limiting
Threshold
::
Nickel, mg/I —
Phenols 1 mg/I
Pesticides
Chlorinated Hydrocarbon
Insecticides mg/I
AWin 0.001
Chlordane 0.003
DDT 0.05
Dieldrin 0.001
Ertdrin 0.0005
Heptachlor 0.0001
Heptachlor Epoxide 0.0001
Lindane 0.005
Methoxychlor 1.0
Toxaphene 0.005
Carbonate and
Grganophosphorus
Pesticides, mg/I 0.1
Chlorophenoxy
Herbicides, mg/I
2,4-D 0.02
2,4,5-TP(SiIvex) 0.03
2.4.5-T 0.002
Range of pH 5.9-S.O
Salenium, mg/I 0.01
Silver 0.05
Sodium Absorption
Ratio, SAR
Sulfate, mg/I 250
Suspended Solids, mg/I —
Soluble Salts, mg/I —
Threshold Odor Number —
Total Dissolved Solids 500
Transparency,
Secehe Disk, ft —
Turdidity, silica
scale units —
Vanadium, mg/I —
Visible Sewage Solids None
Zinc, mg/I 5
Residual Sodium
Carbonate (meq) —
0.2
0.001
0.003
0.05
0.001
0.0005
0.0001
0.0001
0.005
1.0
0.005
0.02
0.03
0.002
0.05
4.5-9.0
0.02
6.5-8.3 6.0-10.0
3,000
0.1
25
15,0
1,000
500-5,000
0.1
2.0
2.5
100 100
256 256
20
50
None None
Soureas: Chan, C.W., "Management of Urban Strom Runoff," American Society of Civil Engineers, Urban Water Resources Research
Program, Technical Memorandum No. 24, New York, 1974.
National Acadomy of Scienca—National Academy of Engineering Committee on Water Quality Criteria, Water Quality Criteria,
1972, USEPA Report No. EPA-R3-73-O33 (NTIS No. PB 236 199/AS), March, 1973.
214
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POLLUTIONAL SOURCES
Impacts on receiving waters are generated by the contribution of pol-
lutants from both urban and non-urban sources» Treated and untreated munici-
pal and industrial wastewater effluents are important contributions. The
direct and indirect additions of pollution due to stortnwater runoff are
also important. Direct contributions may take the form of runoff discharges
and unsewered runoff. Indirect runoff contributions may involve combined
sewer overflows or sanitary sewer bypasses that result from excessive inflow
or infiltration, or other sources of excessive flows.
Non-urban sources include agricultural, silvicultural, and mining land
uses. In addition, the non-point contributions due to erosion from construction
activity may be included as both an urban and non-urban source of pollution.
A major pollutant in non-sewered runoff contributions for both urban and
non-urban land uses is sediment. It has been estimated that 3.6 billion MT
(4 billion tons) of sediment are produced annually through the processes of
erosion. (43) An indication of the relative magnitudes of sediment generation
from non-urban land uses is shown in Table 115.
TABLE 115. REPRESENTATIVE RATES OF EROSION
FROM VARIOUS LAND USES AND
PERCENT OF NON-URBAN PRODUCTION ATTRIBUTABLE TO EACH
Non-Urban
Land Use
Forest
Grassland
Abandoned Surface Mines
Cropland
Harvested Forest
Active Surface Mines
Construction
Ton/mi2/yr
24
240
2,400
4,800
12,000
48,000
48,000
Metric Ton/km2 /yr
8
84
840
1,670
4,180
16,720
16,720
% of Total
Sediment Production
Nationwide
0.5
6.0
84.0
6.0
1.0
1.0
3.0
' Source: United States Environmental Protection Agency — Office of Water Programs, "Methods for Identifying and
Evaluating the Nature and Extent of Non-Point Sources of Pollution," USEPA Report No. EPA-430/9-73-014,
October, 1973.
Although the greatest rates of sediment production are associated with
construction and active surface mining, they represent a relatively low per-
centage of national production on a mass basis. The greatest percentage is
that associated with crop lands. An indication of the pollutional contri-
butions attributable to some non-urban land uses is shown in Table 116.
215
-------
TABLE 116. ANNUAL MASS DISCHARGES FROM SOME RURAL AREAS
Annual Average Load, Ib/ac/yr (kg/ha/yr)
Corn
Wheat
Apple Orchard
Suspended
Solids
13,200
(14,790)
1,730
(1 ,i40)
185
BOD5
120
(134)
15.5
(17.4)
3.7
COD
1,300
{1,460)
170
(190)
27.8
N
237
(266!
31
(35)
0.8
P04
27.7
(31)
3.6
(4.0)
3.9
(207) (4.1) (31.2) (0.9) (4.4)
Sourco: Woldnar, R.B., et al., "Rural Runoff as a Factor in Stream Pollution," Journal of the Water Pollution Control
Federation, 41 S3): 377,1969,
An appropriate measure of the relative strength of direct urban runoff
discharges was shown in Table 92. A similar array of data for combined sewer
overflows is shown in Table 93.
A more meaningful relative comparison of various contaminant contributions
from sources in Des Moines, Iowa appears in Table 117. This estimates the
relative distribution of BOD^, nitrates, and ortho-phosphates from the apparent
sources of these contaminants—treatment plant effluent, bypasses, combined
sewer overflows and urban runoff. Interestingly, approximately 64 percent of the
BODj, 43 percent of the nitrates, and 44 percent of the ortho-phosphates, on an
annual basis, are attributable to controlled and uncontrolled wet-weather sources.
Of these, combined sewer overflows direct runoff represents around 25 percent of the
BOD^, 8 percent of the nitrates, and 2 percent of the ortho-phosphates.
A similar analysis of data collected in Durham, North Carolina, produced
the estimates shown in Table 118, The data are based on a separate system and
attributes about 99 percent of the annual yield of suspended solids, 88 percent
of the ultimate BOD, and 91 percent of the COD to urban runoff alone, with
secondary treatment of sanitary wastewaters. The relative impact of secondary
treatment on the overall annual suspended solids, ultimate BOD and COD delivered
to the receiving water, amounts to only 4 percent, 46 percent, and 48 percent,
respectively. During approximately 20 percent of the year, downstream water
quality is controlled by runoff. (58)
2L6
-------
Condition
WWTP Effluent
Dry Weather
'Wet' Weather
Subtotal
'Wet' Dry Weather Overflow
Wet' Weather Combined
Sewer Overflows
2.72 in. Rain (6.9cm)
1.50 in. Rain (3.8cm)
0.75 in. Rain (1.9cm)
0.375 in. Rain (1.0cm)
0.175 in. Rain (0.4 cm)
Subtotal
Urban Storm Water
2.72 in. Rain (6.9 cm)
1.50 in. Rain (3.8cm)
0.75 in. Rain (1.9cm)
0.375 in. Rain (1.0cm)
0.175 in. Rain (0.4cm)
Subtotal
Total Annual Discharge
TABLE 117
SUMMARY OF PRESENT ANNUAL METRO AREA DISCHARGES
BOD NO3 O.PO4
Days Ib kg Ib kg Ib
kg
257
108
365
108
1
5
12
18
20
56
1
5
12
18
20
56
365
4,060,600
2,246,400
6,307,000
2,235,600
40,500
101,500
32,500
0
0
174,500
292,000
765,000
966,000
495,200
149,800
2,668,000
11,385,100
1,845,700
1,021,100
2,866,800
1,016,200
18,400
46,100
14,800
0
0
79,300
132,700
347,700
439,100
225,100
68,100
1,212,700
5,175,000
400,900
237,600
638,500
9,700
240
680
220
0
0
1,140
6,800
15,300
19,300
9,900
3,000
54,300
703,640
182,200
108,000
290,200
4,400
110
310
100
0
0
520
3,100
6,950
8,770
4,500
1,360
24,680
319,800
1,737,300
1,036,800
2,774,100
263,500
6,350
12,200
3,250
0
0
21,800
3,900
9,200
12,000
6,200
1,900
33,200
3,092,600
789,700
471,300
1,261,000
119,800
2,890
5,540
1,490
0
0
9,910
1,770
4,180
5,450
2,820
860
15,090
1,405,800
Source: Davis, P.L., and F. Borohardt, "Combined Sewer Overflow Abatement Plan, Des Moines, Iowa," EPA-R2-73-170, NTtS PB 234 183, April 1974.
-------
TABLE 118
TOTAL ANNUAL YIELD OF POLLUTANTS FROM
MUNICIPAL AND URBAN RUNOFF WASTES DURING 1972
Suspended
Solids 335
Ultimate BOD 685
COD 1,027
Municipal
Raw
Sanitary Percent
Ibs/ac/yr kg/ha/yr Removal*
Percent
Urban Total Overall
Effluent Runoff Yield Removal
lb»/ac/yr kg/ha/yr Ibs/ac/yr kg/ha/yr Ibs/ac/yr kg/ha/yr Efficiency
375
768
1,151
85
91
91
50
61
92
56
68
103
6,690
470
938
7,497
527
1,051
6,740
531
1,030
7,553
595
1.155
4
46
48
Attum«d
Souroo: Colston, N.V., "Characterization and Treatment of Urban Land Runoff," USEPA Report EPA-670/2-74-096,
Decambar, 1974.
Perhaps a better indication of wet weather effects is shown in Table 119.
Suspended
Solids
TABLE 119
TOTAL YIELD OF POLLUTANTS DURING STORM PERIODS
FROM URBAN RUNOFF AND MUNICIPAL WASTES
Municipal
Raw
Sanitary Percent
Ibs/ac/yr kg/ha/yr Removal*
64
Effluent
Ibs/ac/yr kg/ha/yr
Urban
Runoff
Ibs/ac/yr kg/ha/yr
Percent
Total Overall
Yield Removal
Ibs/ac/yr kg/ha/yr Efficiency
72
146
218
85
91
91
10
12
18
11
13
20
6,617
447
895
7,415
601
1,003
6,627
459
913
7,426
514
1,023
1
20
16
Ultimate BOD 130
COD 195
Source: Colston, N.V., "Characterization and Treatment of Urban Land Runoff," USEPA Report iPA-670/2-74-096,
Decambar, 1974.
During the "wet" weather periods of the year the direct contributions from
runoff are significantly greater than those of wastewater effluents and even
raw sanitary wastes.. In addition, the relative overall removal efficiency can
be estimated to control only one percent of the suspended solids, 20 percent of
the ultimate BOD, and 16 percent of the COD production in the basin. This
represents around one-quarter, somewhat less than one-half, and one-third
respectively, of the overall efficiencies computed for these pollutants on
an annual basis. It is apparent that the relative overall effect of sanitary
wastewater treatment would be even less for individual high intensity rainfall
events.
218
-------
Since non-urban land uses occupy 97 percent of the land area of the United
States, it seems apparent that the largest quantitites of uncontrolled pollutants
originate from these areas, as opposed to urban sources, on an annual discharge
basis. Indeed, the impact of rural contributions on receiving water quality
can be significant. Results from a study in Des Moines, Iowa are shown in
Table 120. This table shows that the majority of organic loadings found in
the Des Moines River originated in upstream rural areas. Only urban ortho-
phosphate contributions were found to approach those from rural areas. The
control and abatement of the contributions of the Des Moines community were
considered insignificant compared to the receiving water demands imposed by up-
stream pollutant sources. (58) Although the annual pollutional discharges from
rural areas are significantly greater than those of urban areas, this does not
dismiss the relative impact or importance of urban pollution sources.
TABLE 120
ESTIMATES OF ANNUAL POLLUTANT CONTRIBUTIONS
FROM URBAN AND NON-URBAN SOURCES, DES MOINES
Parameter
Low Water Year
Ib kg
High Water Year
Ib kg
Average Water Year
Ib kg
BODS
Incoming
Metro Area
NO3
Incoming
Metro Area
O.PO4
Incoming
Metro Area
1 5,549,000
11,385,100
2,431,000
703,640
593,000
3,092,600
7,067,700
5,175,000
1,105,000
319,800
269,500
1,405,700
100,070,000
11,385,100
60,032,000
703,640
7,292,000
3,092,600
45,486,400
5,175,000
27,287,300
319,800
3,314,500
1,405,700
65,225,000
11,385,100
22,222,000
703,640
2,940,000
3,092,600
29,647,700
5,175,000
10,100,900
319,800
1 ,336,400
1 ,405,700
Source:
Davis, P.L.,, and F. Borchardt, "Combined Sewer Overflow Abatement Plan, Des Moines, Iowa," USEPA Report
EPA-R2-73-17O, NTIS PB 234 183, April, 1974.
In urbanized areas, the regrading of land surfaces, the construction of
structures and facilities that result in greater basin imperviousness, and the
installation of drainage structures, all add to higher runoff rates and shorter
times of runoff concentration. This factor, and the array of pollutants, in-
cluding heavy metals, from urban areas, all contribute meaningfully to receiving
water impacts. The significance of land use is shown in Figure 65. In this
219
-------
14:00
ALTERNATIVE LAND USE
(Multiple Residential)
EXISTING LAND USE
(Park)
14:00
10:00
11:00
12:00
13:00
14:00
CLOCK TIME
Figure 65. Effect of changed land use on characteristics of subcatchment runoff from
Shelby Street Watershed, San Francisco
Sourco:
Roesnor, L.A., et al.,
Resources Research
,
, "A Model for Evaluating Runoff Quality in Metropolitan Master Planning,"
Program Technical Memorandum No. 23, New York, N.Y., April, 1974.
ASCE Urban Water
220
-------
figure, the modelling effects of changing land use, from a park use to a multiple
residential use, resulted in higher runoff discharges and generally higher pol-
lutional load from that area by more than 10 times. (80) Thus, although urban
areas represent only three percent of the nation's land area, the relative pol-
lutional contributions and receiving water impacts associated with urban areas
are disproportionate to their size and must be dealt with in order to insure
receiving water quality.
RECEIVING WATER IMPACT
Receiving water impacts are generally the time-related effects of pollution
on the water body. Thus, in a flowing stream, river or estuary, some of the
impact of pollutant contributions may be realized at locations far downstream
from the point of discharge. In addition, certain pollutant additions may pro-
duce depositions that exert long term effects on the aquatic system. In lakes and
other water bodies with long term flow retention capabilities, the most widely
noted impact is eutrophication or the changes due to excessive nutrient enrich-
ment.
Receiving water impacts have been evaluated in a number of ways. These gener-
ally involve the assessment of individual water quality parameters through the
estimation of the mass balance of pollutant loadings in successive segments of the
water body. Of particular interest is the analysis of biological oxygen demand
to assess the effects of biodegradable organic contaminants on dissolved oxygen
levels in a receiving stream. With the advent of the computer, more complex
evaluations of impact have become possible. These may include the modelling of
receiving water hydrodynamics, chemical, and biological pollutant transformations
and their ecological effects on various biota. (97) They may also involve the
impact of specific pollutants on specific biological groupings. (98)
Dissolved Oxygen
Dissolved oxygen concentrations are often considered the most important
indicator of surface water quality. Low concentrations result in poor environ-
mental conditions for fish and other aquatic life. Complete or major oxygen
depletion creates or threatens to provide septic conditions. Aquatic dissolved
oxygen is primarily from atmospheric sources and is also produced by aquatic
plant life. The decomposition of organic pollution by oxygen consuming micro-
organisms may cause large decreases in surface water dissolved oxygen concentra-
tions. Biological oxygen demand, BOD, is a measure of the potential oxygen
depletion associated with the biological decomposition of organic material over
a given time interval and temperature. Decreases in dissolved oxygen depend
upon the amount of BOD in the receiving water, the exertion rate of the BOD,
and also the dissolved oxygen content and the reaeration characteristics of the
water body. (99)
221
-------
Various hypothetical case studies have been developed to indicate the
relative impacts of direct urban runoff and combined sewer overflow contri-
butions on dissolved oxygen levels in receiving waters. One such analysis
involved the estimation of the effects of direct urban runoff on a receiving
stream. (100) The hypothetical city was of 100,000 population and a drainage
area of 50 km2 (19.3 mi2). In addition, the city has 1,368 km (850 mi) of
streets, a street surface contaminant loading of 42 kg/eurb-km/day (150 Ib/curb-
mi/day), and a sanitary wastewater flow of 0.52 m^/sec (12 mgd). Further, an
uncontaminated receiving water of 2.8 m^/sec (100 cfs) and a critical rainfall
event of 6.4 nun (0.25 in) were also assumed. The results of this analysis
produced the discharges shown in Table 121.
TABLE 121
COMPARISON OF STORMWATER AND SANITARY
WASTEWATER DISCHARGES FOR CASE STUDY
Metric Ton/Yr*
Discharge
Raw Storm Water
Raw Sewage
Treated Sewage
(secondary)
Storm Water as
Percent of Storm-
water and
Raw Sewage
Storm Water as
Percent of Storm-
water and
Treated Sewage
Total
Solids
17,000
5,200
520
77
97
COD
2400
4800
480
33
83
Total
BODLPhosphates
1200
4400
440
21
73
50
200
10
20
83
Kjeldahl
Nitrogen
50
800
80
Lead
31
Zinc
6
39
Metric Ton » 1,000 kg = 1.1 tons
Source: Pitt, R.E.. and Field R,, "Water Quality Effects from Urban Runoff," a paper presented at the 1974
American Water Works Association Conference, Boston, Massachusetts.
222
-------
As this table indicates, the major contributions of pollutants would be
attributable to direct runoff when secondary treatment of sanitary sewage was
provided for all contaminants but Kjeldahl Nitrogen. Figure 66 depicts the
projected stream impacts of these contributions on dissolved oxygen levels for
steady state conditions. The analytical approach employed is based on the
assumption that pollutants accumulate in urban drainage basins. The degree
of accumulation is projected in this case to reflect varying effects on the
receiving water.
10-
z
§ «'
TREATED SANITARY WASTEWATER + 16,000 kg
(36,000 Ibl BOOL IN URBAN RUNOFF (5 days accumulation!
345 7
DAYS OF TRAVEL FROM DISCHARGE
10
Figure 66, Oxygen sag curves for case study.
Source: Pitt, R.E., and Field R., "Water Quality Effects from Urban Runoff," Paper presented at the 1974
American Water Works Association Conference, Boston, Massachusetts.
223
-------
Assuming a desirable dissolved oxygen level of 5 mg/1, the level attri~
butable to the effect of treated sanitary effluents is well above this criterion.
The contributions of runoff reflecting the contaminant removals from every one
day's accumulation will force the dissolved oxygen level below the 5 rag/1 limit,
and septic conditions will be realized in the receiving water from the runoff
contributions estimated from five day's pollutant accumulation.
Another steady state analysis was performed on a similar hypothetical city
to suggest the impacts attributable to combined sewer overflows, but not direct
runoff or sources other than sanitary sewage. (101) Although the case study
involved the same population, in this case the drainage area was taken as
81 fcn^ (31 mi^), a. dry-weather flow of 0.55 m3/sec (12.5 mgd) was assumed and
the receiving stream was taken to have a discharge of 56 m^/sec (2,000 cfs).
Data from Bucyrus, Ohio,(57) on overflow quality and a rainfall event with a
recurrence interval of one year produced the results in Table 122 . This table
indicates sag-point dissolved oxygen concentrations and the number of days
during which dissolved oxygen is below a 4.0 mg/1 level for various degrees of
treatment of sanitary sewage and combined sewer overflows. In each case, dry
weather flows alone produced conditions above the 4.0 mg/1 criterion for all
levels of treatment. The net effects of degree of treatment on sanitary effluents
and combined sewer overflows are indicated in both minimum dissolved oxygen levels
and the number of days below standard. The greatest relative beneficial effects
of stream impacts are associated with primary treatment of overflows.
TABLE 122
SAG-POINT DISSOLVED OXYGEN LEVELS
AND THE RELATED NUMBER OF DAYS BELOW CRITERIA
Minimum
Plant Dissolved
Overflows Oxygen, mg/1
Untreated
Primary
Treatment
1.0
2.8
Days
Below
Standard
5
3
Minimum
Dissolved
Oxygen, mg/I
1,8
3.5
Days
Below
Standard
4
3
Minimum
Dissolved
Oxygen, mg/1
2.5
3.9
Days
Below
Standard
4
1
Source: Untltlod paper prepared by Robert Crim, USEPA, Washington, D.C.
The foregoing hypothetical examples, while illustrative, do not reflect
the myriads of other influences that also contribute to receiving water impacts,
Although desirable, few receiving streams can be assumed to be uncontaminated.
Few receiving waters can be considered free of the effects of other sources of
pollution or the residual effects of past rainfall events. The analytical
methods for determining BOD exertion rates for runoff (64) and the methods of
224
-------
assessing receiving water reaeration (102) may be suspect. Even the method
by which discharges are introduced into the receiving water (103) and the
resulting dispersion of discharges in the aquatic environment (104) have an
important bearing on resulting impacts.
A real world theoretical analysis of organic pollutant of storm and
receiving stream was developed in connection with a study of storm and com-
bined sewer pollution in Atlanta, Georgia, and its effects on the South
River. (95) The results of the analysis are shown in Figure 67. The average
annual dissolved oxygen deficits for dry-weather flows are shown, as well as
the projected impacts of a two-week storm confined to the headwaters of the
drainage areas. Average dissolved oxygen concentrations for dry weather flow
amounted to 3.9 mg/1, although minima of 1.9 mg/1 were experienced. Annual
average B"OD loads from separate storm areas were found to be approximately
55 percent of the loads from combined sewer areas.
The impact of direct and indirect runoff contributions are also demon-
strated in the figure for various exertion constants and treatment conditions.
As indicated, the relative influence of storm runoff and combined sewer
overflows are significant for the assumed conditions. It was suggested that
the impacts of combined sewer overflows were due not only to the increased
volume of biodegradable organic materials contributed, but also to higher
deoxygenation rates due to the percentage of sanitary sewage.
Another steady state analysis of receiving water dissolved oxygen concen-
trations on the urbanized Third Fork Creek Basin in Durham, North Carolina,
produced the results shown in Table 123. In this table, the impacts of treated
sanitary effluents and direct runoff contributions were analyzed. Deoxygena-
tion rates in this analysis were determined by the laboratory analysis of
representative runoff samples by COD analysis over time, which were taken to
provide an estimate of ultimate BOD exertion rates. The impact of small
rainfall events was found to be negligible for the assumed conditions. In
addition, treated sanitary effluents exerted no effect on dissolved oxygen
levels. For larger storm events the impact of the various parts of the run-
off hydrograph—the "first flush," hydrograph peak, the falling limb tail—
were evaluated. For each of the larger storms the "first flush" and hydro-
graph peak contributions exert a greater effect on dissolved oxygen than the
remainder of the runoff. This indicates the relative effects of the earlier
components of the runoff event and the significance of the "first flush."
In comparison to a tentative criterion of 5 mg/1 dissolved oxygen, the runoff
pollutional contributions associated with a one to two-year return period
storm or greater, could produce subcritical dissolved oxygen levels in the
receiving water. The enhancement of dissolved oxygen by various levels of
treatment is also shown.
225
-------
J1JKMII. I
mi!«tD IX I
NtJk;*t;i*i
Q- Mil §»lf—«-|
DISTANCE {ft x 10*1
NJ
NJ
ON
60
1
80
f
90
1
i too
i i
SATURHTIOS 0.0. C3HCc:iTB*TION » 8.25 ng/1
J
NOTE:
-CRY WEATHER FLOW--
OiSERVED D.O. PROFILE
A. »LL tmiTP FLOW TREATED; STORM DRAINAGE K, = 0.05
B. ALL WTP FLOW 8T-PASSED; STORM OMiNASE K, =0,05
C. ILL SMTP FLOW TREATED; STORM CRAJNAEE K, =0.10
THEORETICAL D,0. PROFILES
FOR TfO-WEEK STORM
Figure 67. Theoretical annual average dissolved oxygen profiles in South River for two-week storm.
Source: Black, Crow and Eidsness, Inc., "Storm and Combined Sowar Pollution Sources and Abatement," USEPA Report
No. 11024ELB01/71 SNTIS No. PB 201 725), January, 1971.
-------
TABLE 123. RESULTS OF OXYGEN-SAG COMPUTATIONS FOR STUDY WATERSHED
Rain-
fall Du ra-
in tion
Storm Type (cm) (hr)
Small Storm 0.1 1
(0.25)
Small Storm 0.1 3
(0.25)
1-2 year Storm 1.0 5
(2.54)
Is?
"xl
5-year Storm 3.3 5
(8.4)
7-day, 10-year — —
Return
Period Storm
(yr) Component
- Total
Storm
- Total
Storm
1 to 2 First
Flush
Peak
Falling
Limb
Tail
5 First
Flush
Peak
Falling
Limb
Tail
Storm Regeneration Ultimate
Flow Coefficient BOD
(efs) (day:1:) (mg/l)
40
20
200
315
200
75
500
1,100
800
300
0.3
4.00
5.70
1.25
0.86
1.25
2.75
0.58
0.32
0.40
0.90
0.13
40
31
75
62
47
37
85
70
54
42
15
Flow
Deoxygena- Time
tion to Sag
Coefficient Point
(day'1) (day)
0.12
0.12
0.12
Q.12
0.12
0.12
0.12
0.12
0.12
0.12
0.12
0
0
2.0
2.6
1.9
0.8
3.4
4.8
4.2
2.4
6.0
DO
Deficit
at Sag
Point
(mg/l)
0
0
5.6
6.3
3.5
1.4
11.7
14.7
9.7
4.1
11.9
D.O.
at
Sag
Point
(mg/l)
10.0
10.0
4.5
3.8
6.5
8.7
0*
0*
0.3
5.9
0*
no
Point
BOD
St<
20%
_
5.6
5.0
7.2
8.9
0.7
0*
2.3
6.8
0*
(mg/l) at Sag
: With Stated
Removal from
armwater
40%
:
—
6.7
6.3
7.9
9.1
3.0
1.2
4.2
7.6
0*
60%
_
7.8
7.5
8.6
10.0
5.3
4.1
6.1
8.4
0*
Low Flow
•Anaerobic
9
Notes:
1 Treatment Plant Pararntetars for all Cases: Flow = 5.1 cfs
BOD = 27 mg/l
D.O. = 3,3 mg/l
2. Water temperature assumed to be 60°F,
3. Initial stormwatar D.O. estimated at 9.5 mg/l based on watershed observations.
Source: Colston, N.V., "Characteristics and Treatment of Urban Land Runoff," USEPA Report No. EPA-670/2-74-096 (NTIS No. PB 202
865), December, 1974.
-------
An evaluation of the Milwaukee River Watershed (99) in Wisconsin led to
the findings indicated in Table 124 . This table shows estimates of dissolved
TABLE 124. POTENTIAL EFFECT OF COMBINED SEWER OVERFLOWS
ON THE WATER QUALITY OF THE MILWAUKEE RIVER
ABOVE THE NORTH AVENUE DAM3
RIVER CONDITION IN AUGUST WITH AVERAGE FLOW (170cfs)c
WITHOUT OVERFLOW
Rimf.ll
Runoff
Otpth
In,
(cm)
0-0.05
(0-0.13)
0,05-0.10
(0.13-0.25)
0.10-0.30
(0.25-0.76)
0.30-0.60
(0,76.1.5)
0.60-1-00
(1.5 -2.5)
1,00-2,00
(2.5 -5.1 >
4.0O-5.00
(10,2 -12.7)
Volume of
Combined
Sewer
Overflows'1
Annual Number ac-ft
of Runoff
EvurrtJ
16
8
15
3
3,25
1.32
0.12
(ha-ra)
Per E»ent
4.4
(0.54)
13.2
( 1.6)
35
( 4.3)
78
( 9.6)
140
(17.2)
.260
(32.0)
700
(86.3!
BOD Per Voluma/Day
Event*
Ib (kg)
1,800
(816.5)
5,400
(2449.4)
14,000
(6350.3)
32,000
(14515.0)
58.000
(26308.0)
108,000
(48987.7)
287,000
(130180.3)
ac-ft
(ha-m)
340
(42)
340
(42)
340
(42)
340
(42)
340
(42)
340
(42)
340
(42)
BCD/Day
Ib (kg)
4,600
(2,087!
4,600
(2.087)
4.600
(2,087)
4,600
(2,087)
4,600
(2,087)
4,600
(2,087)
4,600
(2,087)
DO
Ib/gal
fms/l!
42
(5.0)
42
(5.0)
42
(5.0)
42
(5.0)
42
(5.0!
42
(5.0)
42
(5.0!
WITH COMBINED SEWER OVERFLOW
Volume/Day
ac-ft (ha-m)
344
(42!
353
(44)
375
(46!
418
(52)
480
(59)
600
(74)
1,040
(128)
BOD'
Ib (kg)
6,400
(2,903)
10,000
(4,536)
18,600
(8,437)
36,600
(16,601)
62,600
(28,395)
112,600
(51,074)
291,000
(132,267)
Ib/gal
(rng/l)
58
(7)
83
(10!
150
(18!
267
(32)
401
(481
576
(69)
860
(103)
DOd
24 Hour
After
Overflow
Ib/pl (mg/l)
33
(3.93)
26
(3.07)
3.0
(0.35)
0
0
0
0
*far purpotat of thli computation, »»ch overflow evem it aftyrned to mix with the volume of river flow for one day.
blm*rc«otOf iew*r capacity atiumad to be 1.0 DWF, contributing area equals 2,100 ac (850 ha).
cAvir»e* Aufluit river flow bated on 16 yean of record (1949-1964) for Ettabrook Park gsuga. Average 5-dav 20°C BOD of river and combined «ewer overflow.
(*Q;!ia!v*a> o*vSr»rt concentration *t wmmar water temperature of 77°F (25°C3.
'ffeetuancy an§*yi!t b««d on 16 v«*ff of record (1949-19641 in tne Chicago metropolitan »r*«.
'AvarcQ* 5
-------
oxygen concentrations in the river for both dry and wet-weather conditions.
All wet-wether contributions have been assumed to take the form of combined
sewer overflows, with a BOD .concentration of 150 mg/1. The comparison of dis-
solved oxygen concentrations for dry and wet-weather conditions suggests the
relative impact of combined sewer overflows estimated to annually contribute
about 10 percent of the average BOD arriving at the North Avenue impoundment
during an average year. In an average year the remaining 90 percent of annual
BOD originates in upstream flows and is due to industrial discharges, non-
sewered runoff, stormsewer discharges, and sanitary sewer system bypasses.
It should be noted, in addition, that the dissolved oxygen concentrations cited
do not reflect sag point conditions, but rather conditions 24 hours after the
overflow.
An analysis of the impacts of organic loadings on the Upper Potomac Estuary
in Washington was performed to evaluate their effects on dissolved oxygen levels
in various reaches of the receiving water. (106) A plan of the Potomac Estuary
and the major receiving water quality problems identified in this water body
are depicted in Figure 68. As an estuary, the receiving water is subject to
tidal influences. The new outflow velocities experienced in the estuary due
to these influences are shown in Table 125. As part of the overall analysis,
data from two separate years were evaluated. One year, 1966, represented a low
annual flow within the estuary while the second year, 1971, was one with an
average annual flow.
A BODe profile of the estuary appears in Figure 69. This figure indicates
both acutal data and modelled estimates of BODc concentrations. Definite BODc
peaks can be discerned from this profile. These were due to pollutional contri-
butions from the discharges of Rock Creek, the Anacostia River and the treated
effluents of the Blue Plains Wastewater Treatment Plant. The peaks at Rock
Creek and the Anacostia River were not as discernible in the dry-weather BODc
profiles for the average flow year, 1971. A related low flow dissolved oxygen
concentration profile is shown in Figure 70. This indicates the modelled and
actual dissolved oxygen responses to the organic loadings represented for low-
flow conditions. Both modelled and actual profiles depict substandard levels
in various parts of the estuary. One of the major contributions to low dis-
solved oxygen levels is the treated effluents discharged from the Blue Plains
Treatment Plant.
The effects of a storm event on the estuary are shown in Figure 71. Pre-
storm conditions show a small peak due to Rock Creek contributions and significant
additions due to the effluent from the Blue Plains Treatment Plant. Under storm
conditions the contributions from direct and indirect runoff are apparent. The
additions from Rock Creek are significant for the assumed storm conditions.
Over time, the peak can be seen to proceed downstream.
An indication of the effects of dry-weather flow treatment is indicated in
Figure 72. These data demonstrate the depression of dissolved oxygen levels
associated with storm runoff and combined sewer overflows, over time, even though
higher quality effluents are being discharged from the treatment facility. Thus,
storm runoff and combined sewer overflows may exert a significant impact on
receiving water bodies, and this must be considered in the analysis of receiving
water quality.
229
-------
Periodically
High Bacterial
Densities
Periodically High
Bacterial Densities
and Low Dissolved
Oxygen Levels
Periodically Moderate
Bacterial Densities
Low Dissolved
Oxygen Levels and
Beginnin of
Algal Blooms
Pronounced
Nuisance Algal
Growths
Brackish
Waters
Sourc»:
Figure 68. The Potomac estuary and its major pollution problems.
Matcalf and Eddy Engineers and Water Resources Engineers, Inc., "Reconnaissance Study of Combined Sewer
Overflows and Storm Sewer Discharges," a report prepared for the Department of Environmental Services,
District of Columbia, Washington, D.C., March, 1973.
230
-------
TABLE 125. TIDAL AND NET RIVER VELOCITIES
Downstream
24-HOUR VELOCITY, mi/day (km/day)
Upstream
Net
Location
Potomac River
1. Roosevelt
Island
2. Just below
Blue Plains
Plant
3. Hallowing
Point
1966
1.21
(2.02)
5.16
(8.60)
5.86
(9.77)
1971
3.27
(B.45)
5.91
(9.85)
5.80
(9.67)
1966
0.46
(0.76)
4.43
(7.38)
5.54
(9.23)
1971
0
(0)
3.36
(5,60)
4.90
(8.17)
1966
0.75
(1.25)
0.73
(1.22)
0.32
(0.53)
1971
3.27
(5.45)
2.55
(4.25)
0.90
(1.50)
Anacostia River
1. Main River at 1.22 1.47 1.11 0.81 0.11 0.66
Upper End of (2.03) (2.45) (1.85) (1.35) (0.18) (1.10)
Kingman Lake
2. Between 0.90 0.90 0.89 0.80 0.1 0.02
Douglas & (1.50) (1.50) (1.48) (1.48) (0.16) (0.03)
11th Street
Bridges
Source: Metcalf and Eddy Engineers and Water Resources Engineers, Inc., "Reconnaisanee Study of Combined Sower
Overflows and Storm Sewer Discharges," a report prepared for the Department of Environmental Services,
District of Columbia, Washington, D.C.. March, 1973.
231
-------
(Major outfall)
(Tributaries)
(Major outfall)
(Tributaries)
(Plant effluent)
(Major outfall)
12H
A Chain Bridge
B Mouth of Rock Cr.
C 14th St. Bridge
D Mouth of the Anacostia River
E Blue Plains Plant
F Ft. Washington
Case: Dry Weather Flow
Year 1966
Flow 880 cfs (25.3 m3/sec)
Temp. 80.6° F {27°C>
Actual Data
Model Data •
\
29 mi
48.1 km
Source:
DISTANCE FROM CHAIN BRIDGE
Figure 69. BOD5 in the Potomac estuary,
1966 dry weather.
Metcalf and Eddy Engineers and Water Resources Engineers, Inc., "Reconnaissance Study of Combined Sew®r
Overflows and Storm Sewer Discharges," a report prepared for the Department of Environmental Services,
District of Columbia, Washington, D.C., March, 1973.
232
-------
MAIN RIVER
(Major outfall) A Chain Bridge
(Tributaries) B Mouth of Rock Cr.
(Major outfall) C 14th St. Bridge
(Tributaries) D Mouth of the Anacostia River
(Plant effluent) E Blue Plains Plant
(Major outfall) F Ft, Washington
Case; Dry Weather Flow
Year 1966
Flow 880 cfs (25.3 m3/sec)
Temp. 80.6° F (27° C)
Standard '
Actual Data —
Model Data
10-
A
8 -
1
o
Q
x
ifiiiiiiiuiiif iiiiiiniiiiiiiiiiiiiiiiii
T—
5
8.3
I I 1—
10 15 20
16.6 24.9 33.2
DISTANCE FROM CHAIN BRIDGE
25
41.5
29 mi
48.1 km
Figure 70. Dissolved oxygen in the Potomac estuary.
1966 dry weather.
Source: Metealf and Eddy Engineers and Water Resources Engineers, Inc., "Reconnaissance Study of Combined Sewer
Overflows and Storm Sewer Discharges," a report prepared for the Department of Environmental Services,
District of Columbia, Washington, D.C., March, 1973.
233
-------
(Major outfall) A Chain Bridge
(Tributaries) B Mouth of Rock Cr.
(Major outfall) C 14th St. Bridge
(Tributaries) D Mouth of the Anacostia River
(Plant effluent) E Blue Plains Plant
(Major outfall) F Ft. Washington
Case: Simulated Storm, August 27,1971
Year 1971 Background
Flow 4,761 cfs (135.2 m3/sec)
Actual Data
Model Data
Pre Storm
Storm 1
Storm 2
T
29
48.1
ml 0 5 10 15 20 25
km 8.3 16.6 24.9 33.2 41.5
DISTANCE FROM CHAIN BRIDGE
Figure 71. BOD5 in the Potomac estuary.
1971 storm condition.
Source: Motcalf and Eddy Engineers and Wator Resources Engineers, Inc., "Reconnaissance Study of Combined Sewer
Overflows and Storm Sewar Discharges," a report prepared for the Department of Environmental Services,
District of Columbia, Washington, D.C., March, 1973.
234
-------
(Major outfall) A Chain bridge
{Tributaries) B Mouth of Rock Cr.
(Major outfall) C 14th St. Bridge
(Tributaries) D Mouth of the Anacostia River
(Plant effluent) E Blue Plains Plant
(Major outfall) F Ft. Washington
Case: Dry Weather Flow
Year 1966
Flow 890 cfs (25.3 m3/sec)
Temp, 80.6° F (27° C)
Standard
Actual Data
Model Data
B
I
C
I
D
I
E
i
8-
o
Q
AFTER UPGRADING
4-
2-
iiiiiiiiiiiiiiniiiii
iiiiiiiiimn
MAIN RIVER
BEFORE UPGRADING
-r
-I-
mi
km
5
8.3
10 16 20
16.6 24.9 33,2
DISTANCE FROM CHAIN BRIDGE
25
41.5
29
48.1
Figure 72. Dissolved oxygen in the Potomac estuary due to dry-weather
flow treatment enehaneement.
Source:
Lager, John A,, P.E., Vice President, Metcal and Eddy, Inc., "Application of Simplified Math Models for
Combined System Impact Analysis," Palo Alto, California.
235
-------
An assessment of a lake response to the contribution of oxygen-consuming
contaminants was performed as part of the study of Onondaga Lake in New York.
(105) In this analysis, the total oxygen demand was estimated to reflect the
contributed effects of both carbonaceous and nitrogenous oxygen demand. Suf-
ficient nitrifying bacteria were found in the lake waters, on the basis of
20-day oxygen demand tests, to indicate a significant impact.
An evaluation of lake hydrodynamics based on the structure of the lake
and water currents produced the "stabilization zone" depicted in Figure 73 .
The "stabilization zone" is defined as that volume of the lake that will ef-
fectively stabilize the major sources of total oxygen demand under critical
conditions of minimal lake water currents. Estimates of total oxygen demand
for a number of sources were used in the analysis. These included waste dis-
charges, air pollutants, benthic demand and the total oxygen demand produced
within the lake itself.
Air pollution contributions were defined from a country-wide air pollution
study, benthic demands were estimated from core samples and waste discharge
contributions were determined from a detailed waste discharge survey of tribu-
tary streams. The lake stabilization depicted is a response to the average daily
additions of total oxygen demand from each of these sources. Assumed variations
in total oxygen demands to the receiving waters resulted in the curve shown in
Figure 74 . This curve relates the percentage of dissolved oxygen saturation at
17.4°C (63.3°F) for various levels of total oxygen demand contributions to the
lake. A comparison of estimated existing loadings and projected loadings due to
new sewage treatment facilities are shown in Table 126.
The indicated values are average daily loadings, based on a grab sampling
program, with the exception of combined sewer overflows. Overflow quality esti-
mates were taken as a percentage of the BOD tributary to the Metro Treatment
Plant. These estimated loading values in Figure 74, indicate that septic
conditions would be experienced with existing daily loadings and that approximate-
ly 50 percent of the saturated dissolved oxygen level (4.7 mg/1) could be realized
by improvements to treated wastewater effluents. In this analysis, combined
sewer overflows were considered relatively insignificant. The values assigned,
however, were based on average conditions and as such, may not reflect the im-
mediate impacts of direct runoff contributions throughout the tributary area
other than overflows on select tributaries. These might be expected to produce
greater short-term effects than shown.
The previous analyses have centered primarily on the impact of the apparent
direct pollutional contributions of storm runoff and combined sewer overflows.
The effects of shock loadings of biodegradable organic materials due to indivi-
dual rainfall events, may appear to represent relatively transient conditions
which, while undesirable, will dissipate over relatively short periods of time.
Longer-term impacts may also result from these and other pollutional contribu-
tions to the receiving water body.
A study of receiving water impacts on the Menomonee and Milwaukee Rivers in
Milwaukee, Wisconsin, disclosed some of these longer-term impacts. (99) This study
was conducted to evaluate a combined sewer overflow detention tank and its effects
236
-------
KJ
LO
,LAKE STABILIZATION ZONE
Based on Critical Conditions
AIR POLLUTION
950 Ib/day (431 kg/day)
I
LAKE OUTLET
NINE MILE CREEK
1,902 Ib/day
(864 kg/day)
HARBOR BROOK
1,647 Ib/day
(748 kg/day)
ONONDAGA CREEK
4,562 Ib/day
(2,071 kg/day)
BENTHIC DEPOSITS
LEY CREEK
67,891 Ib/day
(30,823 kg/day)
THERMOCLINE
29.5-39.4 ft (9-12 m)
\
\
\
\
\
Ib/day — Present daily average discharge of TOD5,
unless otherwise noted
LCSTP — Ley Creek Sewage Treatment Plant
MSTP — Metro Sewage Treatment Plant
PRESENTLY BEING
PUMPED TO MSTP
Figure 73. Onondaga Lake stabilization zone.
Source: O'Brien and Gere Consulting Engineers, "Onondaga Lake Study," USEPA Report No. 11060FAE4/71 (NTIS
No. PB 206 472), April, 1971.
-------
804-
70--
ui 6°--
5
2
O
<
OS
3
O
Q
50--
40--
30-_
20--
10--
140
120
BASIS OF CALCULATION:
Critical Conditions
Lake Temperature
DO in Lake (OLDO)
BOD5 in Lake {OLBOD5j
Deoxygenation Rate (K^)
DO Saturation
TOD5 Input (TULBS)
63.3° F (17.4°C)
0.66 mg/l
6.41 mg/I
0-18/day
9.46 mg/l
126,000 Ib/day
(57,567 kg/day)
Note: Projection curve accounts for
nitrogeneous oxygen demand,
NOD = 0.28 BOD
60
50
40
40 | 20
15
Ib x 103
kg/103
TOD5 INPUT TO LAKE
Figure 74. Lake dissolved oxygen versus BOD input.
Source: O'Briari and Gere Consulting Engineers, "Onondaga Lake Study," USEPA Report No. 11060FAE4/71 {NTIS No,
PB 206 472). April. 1971.
TABLE 126. EXISTING AND PREDICTED LOADINGS
TO ONONDAGA LAKE
Existing Loadings Existing Future Loadings
TODS
Ib/day kg/day Ib/day kg/day
Metro Plant Effluent
Ley Creek Plant Effluent
Lay Creek
Onondaga Creek
Harbor Brook
Combined Sewer Overflows
Nine Mile Creek
Steel Mill
Air Pollution
Benthic Demand
48,791
67,891
4,562
1,647
10,750
1,902
945
950
100
22,200
30,860
2,070
750
4,890
860
430
430
45
8,100
13,381
4,562
1,647
10,750
1,902
945
950
100
3,690
6,080
2,070
750
4,890
860
430
430
45
Total
137,538
62,500
43,337
19,700
Sourco: O'Brien and Gere Consulting Engineers, "Onondaga Lake Study," USEPA Report No, 11060FAE4/71
(NTIS No. PB 206 472), April, 1971.
238
-------
on receiving water quality. Benthai deposits in the Milwaukee River were found
to demonstrate a marked capacity to degrade water quality as measured by dis-
solved oxygen. An indication of this effect at two monitoring stations is
shown in Figure 75. This figure shows that from 0,8 to 2.0 mg/1 of dissolved
Model Verification
Model Without Benthal
Oxygen Demand
0 = 0900 5/17/72
12
10
O)
o
X
o
0
111
>
o
%
ST. PAULAVE
Station 52
0 10 30 50 70 90 110 13O 150 17O 190
5/17 ' 5/18 ' 5/19 I 5/20 I 5/21 1 5/22 I 5/23 I 5/24 I 5/25
Wed Thu Fri Sat Sun Mon Tue Wed Thu
TIME (hrs)
M
O
WATER ST
Station 59
i
O 10
30
50
70
90
5/17
Wed
110
'
130 150
170 190
' 5/18 I 5/19 I 5/20 I 5/21 ' 5/22 ' 5/23 I 5/24 I 5/25
Thu Fri Sat Sat Sun Tue Wed Thu
TIME (hrs)
Figure 75. Oxygen demand effects of benthal deposits on dissolved oxygen levels.
Source: Consoer, Townsend and Associates, "Detention Tank for Combined Sewer Overflow, Milwaukee, Wisconsin,"
Demonstration Project prepared for the Milwaukee Department of Public Works, Wisconsin Bureau of Engineers, USEPA
No. EPA-600/2-75-071 (NTS No. PB 250 427), December, 197S.
239
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OKygen variation was due to these deposits. The variation in these benthal
effects, with respect to increasing flows in the Milwaukee River, appear in
Figure 76. This figure shows a reduction in dissolved oxygen deficits due to
benthal deposits with increasing flow, as would be appropriate for a finite
pollutant source. Thus, in mature streams and in other water bodies where
sedimentation processes may occur, the deposition of contaminants may be ex-
pected to contribute to longer-term quality impairment. The resuspension of
these contaminants caused by the flushing effects of large quantities of run-
off can also magnify the impact of these events on water quality.
te I
Ul —
CC H
Si
§ O
3 a
WATER STREET
BOTTOM DEMAND = 4gm/m2-day
Survey I
Survey 111
Survey IV
100
200 300 400 500
MILWAUKEE RIVER FLOW (cfs)
HUWIBOLDT AVENUE
600
700
Figure 76. Dissolved oxygen deficit due to benthal oxygen demand.
Source: Consocr, Townscnd and Associates, "Detention Tank for Combined Sewer Overflow, Milwaukee, Wisconsin,"
Demonstration Project prepared for the Milwaukee Department of Public Works, Wisconsin Bureau of Engineers, USEPA
No. EPA-600/2-7 5-071 (NTS No. PB 250 427), December, 197S,
240
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Nutrients
Abundant contributions of nutrients to a receiving water can produce
nuisance conditions due to the growth of algae and aquatic plants, the pro-
duction of highly organic sediments, and radical variations in dissolved oxygen
concentrations due to the photosynthetic activity of these algae and plants.
In lakes, nutrient enrichment can be a critical consideration in L'he benefi-
cial uses of the water bodies. The effects of nutrient enrichment have been
defined as:
• A steady decrease in the dissolved oxygen content of the hypolimnion
when measured prior to the fall overturn.
• An increase in anaerobic areas in the lower portions of the hypolimnion
• An increase in dissolved materials, especially nutrients such as nitro-
gen, phosphorus, and simple carbohydrates
» An increase in suspended solids, especially organic materials
• A shift in aquatic organism community structure, involving changes
in species types and the abundance of species and biomass
• A steady decrease in light penetration
• An increase in organic materials and nutrients, particularly phos-
phorus, in bottom deposits
• Increases in total phosphorus in the spring of the year. (94)
Few simple generalizations can be expressed covering nutrient loadings,
concentrations, and the production of aquatic biota due to a number of physical
influences such as receiving water depth, shore line extent, flow-through and
detention time. (75) An indication of specific loading level guidelines are
shown in Table 127.
TABLE 127. PERMISSIBLE LOADING LEVELS FOR TOTAL
NITROGEN AND PHOSPHORUS
Ib/yd2/yr(gr/m2/yr)
Mean Depth
Up To:
ft m
16.4
32.8
164.0
328.1
492.1
656.2
5
10
50
100
150
200
Permissible Loading, Up To:
N P
1.0
1.5
4.0
6.0
7.5
9.0
(0.54)
(0.8 S
(2.2 )
(3.3 }
(4.1 )
(5.0 )
0.07
0,10
0.25
0.40
0.50
0.60
(0.04)
(0.05)
(0.14)
(0.22)
(0.27)
(0.33)
Dangerous Loading in Excess Of:
N P
2.0
3.0
8.0
12.0
15.0
18.0
(1.1)
(1.6)
(4.3)
(6.5)
(8.15
(9.7)
0.13
0.20
0.50.
0.80
1.00
1.20
(0.07)
(0.11)
(0.27)
(0.43)
(0.54)
(0.65)
Source: Bartsch, A.F., "Rote of Phosphorus in Eutrophication," US6PA Report No. EPA-R-3-72-001 ENTIS No. PB 228
•>£>?! Aunii«t 1Q7?
292), August, 1972.
241
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The addition of nutrients to receiving waters is an extremely complex pro-
cess that must take into account transport mechanisms involving groundwater,
point source discharges, overland flow, precipitation, atmospheric and dustfall
contributions, and other source contributions such as nutrient enrichment due
to resident flora and fauna. (35) It is generally considered that the effects
of nutrient enrichment can be best controlled in the light of available treat-
ment technologies by limiting the amount of phosphorus contributed to receiving
waters. (29)
An estimated nutrient balance for the Milwaukee River Watershed is shown
in Table 128. In this tabulation, the major contributions of phosphorus are
due to rural and agricultural runoff. Urban runoff, although significant on a
per-unit basis, is relatively unimportant from the standpoint of the percentage
of the basin attributable to urban land uses. Some of the effects of this
nutrient and aquatic plant-rich river environment on diurnal dissolved oxygen
levels are shown in Figure 77. The data demonstrates the variations in dis-
solved oxygen concentrations that may occur as a result of the photosynthetic
activities of aquatic life. These variations range from 1.5 to 10 mg/1 in a
single day.
As might be expected, radical diurnal changes in dissolved oxygen levels
within a receiving water can cause a severe upset to the aquatic system and
endanger various species of resident biota. Although the Milwaukee River water-
shed is primarily non-urban in character, the loading rates suggested indicate
the potentials of the nutrient enrichment from urban receiving waters. A study
of 52 lakes in the Minneapolis-St. Paul, Minnesota, area (96) showed that the
quality of storm runoff was generally inferior to lake quality. Total coliform
levels were 35 times greater, total phosphorus was six times greater, total
Kjeldahl nitrogen was four times greater, and chloride levels were three times
greater, on the average, than the assumed threshold concentration of 100 ppb
that may produce eutrophication and poor aesthetic quality. Of the 52 lakes
surveyed, 25 percent had phosphorus concentrations larger than this threshold
value. This was generally attributable, in part, to storm runoff since all
other identified wastewater effluents are discharged to the river system in the
area.
Nutrient enrichment is an important consideration in evaluation of receiving
water impacts. Enrichment can produce nuisance aquatic plant life that, in
turn, can create environmental conditions deleterious to other receiving water
biota, as well as an impairment to receiving water aesthetics. Urban runoff is
a rich source of nutrients that can upset the balance of urban receiving waters.
Interestingly, it has been found that although low concentrations of phosphate will
slow algal growth rates, total algae production is dependent on the degree of
phosphate replenishment from available sources, (107) Thus, even though advanced
wastewater treatment may provide effective phosphorus control for domestic and
industrial sanitary waste flows, untreated urban runoff may provide a consistent
source of phosphate replenishment.
242
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TABLE 128. MAJOR SOURCES OF PHOSPHORUS
IN THE MILWAUKEE RIVER WATERSHED
UNDER 1967 CONDITIONS
(Ib/yrx0.45 = kg/yr)
Source*
Unit
Amount of Phosphorus
Above At
West Bend North Branch
Ib Percent Ib Percent
At Milwaukee At Milwaukee River
County Line North Avenue Bay North Branch Cedar Creek
Ib Percent Ib Percent Ib Percent Ib Percent
N3
W
Urban Runoff
Rural and Agricultural
Runoff
Sewage Treatment Plant
Effluent
Private Sewage
Disposal Systems
Sanitary Sewer
Overflows
Combined Sewer
Overflows
460lb/m2/yr
60lb/m2/yr
1.9 Ib/capita/yr
0.2 Ib/capita/yr
b
c
800
12,500
6,000
1,000
b
H c
5
61
30
5
—
—
2,600
16,000
29.000
2.000
b
C
5
32
59
4
—
7,200
37,000
60,000
7,000
b
c
7
33
54
6
—
—
29,400
37,000
60,000
7,000
168,000
30,000
5
11
18
2
51
9
1,000
9,000
2,000
1,000
b
c
8 1,300
69 8,000
15 13,000
8 1,000
b
c
6
34
86
4
__
—
Total
20,300 100 49,600 100 111,200 100 331,400 100 13,000 100 23,300 100
Contributions from precipitation onto water surfaces and from industries were considered neglibible.
Contributions considered negligible in upstream areas. The volume of overflow that takes place annually in Milwaukee County upstream irom the North Avenue Dam was estimated to be
2.73G million gallons with phosphorus concentration as P equal to 2/3 of 10.7 rng/l (strength of bypassed influent Jones Island Sewage Treatment Plant).
cthere are no combined sower service areas in the Milwaukee River watershed upstream from Milwaukee County. The volume of overflow that takes place annually upstream from the North
Avenue Dam was estimated to be 745 mg with phosphorus concentrations as P equal to 45 percent of 10.7 mg/l.
Source: Southeastern Wisconsin Regional Planning Commission, "A Comprehensive PJan for the Milwaukee River Watershed: Inventory, Findings and Forecasts, Regional Planning Commission,
Waukesha, Wisconsin, December, 1970.
-------
— 18
oi
O
16
3 Day Average, July 29-31, 1968
Mid-Afternoon DO
Early Morning DO
Average Temperature 73.4° F (23°C)
DO Saturation at 23°C - 8.4 mg/l
Mid-Afternoon
16
18
64
107
62
103
60
100
58
97
56
93
54
90
52
87
50
83
48
80
46
77
ml
km
DISTANCE DOWNSTREAM FROM WOOLEN MILLS DAM
Figure 77. Measured dissolved oxygen profile.
West Bend-Waubeka reach of the Milwaukee River,
summer 1968.
Sourcn: Southeastern Wisconsin Regional Planning Commission, "A Comprehensive Plan for the Milwaukee
River Watershed: Inventory, Findings and Forecasts," Waukesha, Wisconsin, December, 1970.
Miscellaneous Receiving Water Impacts
The foregoing discussion has emphasized the impacts of biodegradable
organic contaminants and nutrients on receiving waters. Other important re-
ceiving water impacts may be attributable to such other factors as tempera-
ture changes, chlorides, pesticides, heavy metals, and other toxic materials.
Temperature effects can be attributed to deforestation activities, stream
channelization, and the impoundment of flowing water. (94) It has been found
that average temperature elevations about 4°C (7°F) above ambient summer
temperatures in a marine environment caused almost barren conditions where few
animals and almost no micro-algae or seagrasses existed, between 3 and 4°C
(5.4 and 7°F), serious depletion occurred in the biota, and between 2 and 3°C
(3.6 and 5.4°F), damage to the summer biota occurred. (108)
244
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In Minneapolis-St. Paul, higher runoff chloride concentrations due to winter
snow and ice control activities were noted. Mean winter concentrations were
found to be around 300 mg/1 while summer runoff concentrations were approximately
24 mg/1. Annual contributions to the lake system amounted to 5.1 mg/1. It was
found that high chloride concentrations provided a stimulus to the growth of
blue-green algae, a major local lake nuisance. High level lake concentrations
also cause an incomplete turnover of domestic lakes that prevent the oxygen
rejuvenation of deep lake water. (96)
Runoff has been found to be the major transport mode for various herbicides
(109) and pesticides. (110) The soil insecticides such as dieldrin, and herbicide
Trifluralin, have been found to accumulate in fish and snails in concentrations
above those found in the water. (92) A representation of the pesticide residues
found in a number of water bodies is shown in Table 129.
TABLE 129. PESTICIDE RESIDUES MEASURED IN
VARIOUS RECEIVING WATER BODIES
Concentration in mg/l
Location Dieldrin Endrin DDT DDE ODD Heptachler BHC
Great Lakes Region*
St. Lawrence River: ND ND ND .002 ND ND ND
Massena, N.Y.
Lake Erie: Buffalo ND ND ND ND ND ND ND
N.Y.
Detroit River: Detroit ND ND ND ND ND ND ND
Michigan
St. Mary's River: Sault ND ND ND ND P ND ND
Ste. Marie, Michigan
Lake Superior: ND 0.022 0.026 P rO.005 ND ND
Duluth, Minn.
Lake Michigan: ND ND ND ND ND ND ND
Milwaukee, Wis.
Maumee River: Toledo ND ND ND ND 0.006 ND ND
Ohio
St. Joseph River: P 0.29 ND ND 0.013 ND 0.003
Benton Harbor, Mich.
Grand River: Grand P ND ND ND 0.009 ND ND
Haven, Mich.
Detroit River, Grosse ND ND ND ND 0.012 ND ND
Ponte, Mich.
Fox River: Green ND .007 ND ND0.007 ND ND
Bay, Wis.
ND — indicates none detected.
P — Indicates presumptive. Data are reported as presumptive in instances where the results of chromatography were
highly indicative but meet all requirements for positive identification and quantification.
•Agricultural Pollution of the Great Lakes Basin, Combined Report by Canada and the United States, July 1, 1971.
245
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Polychlorinated biphenyls were also found to accumulate in snails and
fish increasingly as the number of chlorine substituents increased. (92)
Many of these materials show some toxic effects on various receiving water
biota at sustained low-level concentrations.
The effects of heavy metals buildup in receiving waters are not well
understood. Their toxicity is well established and their unabated discharge
is a cause for concern. (90) Dangerously high lead concentrations have been
measured in snow melt runoff (96) as well as urban storm runoff. (Ill) Other
significant metals have been noted, as well.
Receiving Water Components
Various analyses have been performed to assess the impact of runoff on
receiving water bodies, both hypothetical and based on actual data. The results
of these analyses on the transient and longer-term effects of biodegradable
contaminants and their effects on dissolved oxygen levels, nutrients and
nutrient impacts, and miscellaneous contaminants, point to an array of consistent
conclusions:
• Direct and indirect urban runoff contributions can be a significant
source of pollution. *
• The pollutant percent loadings in sewers and in non-sewered urban
runoff provides one estimate of the annual distribution of various
pollutants in major wastewater flows across the country, as shown
in Table 130.
TABLE 130. POLLUTANT PERCENT LOADINGS IN SEWERS
AND IN NON-SEWERED URBAN RUNOFF
PERCENTAGES OF INDIVIDUAL COMPONENTS IN EACH STREAM
Combined Sanitary Storm Non-Sewered
Sewers Sewers Sewers Urban Runoff
BODS
COD
SS
N
P
Inorg. DS
28.6
27.7
26.3
29.3
28.1
29.4
61.2
48.0
28.6
63.2
61.2
70.6
4.5
10.8
20.1
3.3
4.8
0
5.6
13.5
25.1
4.2
5.9
0
% Coliforms/yr
Total MPN Coliforms 29.2 70.1 0.3 0.4
Sourco: Boition, H.E., "The Relative Magnitudes of Municipal Water Pollution Problems," an unpublished
EPA paper, September, 1974.
246
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This table shows that approximately 40 percent of the BOD, 50 percent of
the COD, and 60 percent of the suspended solids are associated with combined
sewers, storm sewers, and non-sewered urban runoff flows.
* Under given wet-weather conditions, direct and indirect storm
runoff can govern the quality of receiving waters because of
their shock impact characteristics.
* High levels of dry-weather treatment may not insure receiving
water quality under wet weather conditions.
» The abatement of runoff-related pollution may be more cost-
effective than providing higher levels of dry-weather flow in
many circumstances.
Hence, direct and indirect runoff should not be casually dismissed if
effective means of insuring receiving water quality are to be achieved.
Urban runoff in its many forms is an important aspect of urban wastewater
pollution and it warrants careful consideration as a necessary added dimen-
sion in local, regional, and national water resources planning.
247
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SECTION VI
DATA NEEDS
One of the essential features of the study has been the development
of an analytical framework that provides the quality and quantity charac-
terization of direct stormwater runoff pollution. The informational outputs
from this type of activity can reveal not only the total magnitude of
pollutional loads entering receiving waters but also holds the key to iden-
tifying the relative effects and relationships of the various existing
pollutional sources. Based on this knowledge of relative pollutional con-
tributions from the many sources, alternative plans for abatement and control
can be identified and evaluated in terms of program costs and related
benefits. Such an analysis will provide a basis for the reduction of the
pollutional impact on receiving waters in an efficient fashion.
To accomplish these objectives it is necessary to bring into use various
analytical tools. Such, tools are necessary due to the extremely complex
nature of the component parts of the many physical processes that constitute
runoff phenomenon and the high level of interaction between these processes.
In view of this complexity it is extremely difficult, if not impossible, to
provide meaningful information regarding the above objectives without taking
advantage of various analytical techniques that are available.
The state of the art methodology for providing the needed informational
outputs requires a large amount of data. This section of the report will
present a critical review of existing data and discuss the data requirements
for using and validating the tools at our disposal that can provide the re-
sults necessary for the evaluation of stormwater runoff pollution.
EXISTING DATA
The existing data sources have been reviewed in detail in the foregoing
sections. These data can best be described as:
• Collected for purposes that are extremely different from one
data set to the next,
• Collected for types of pollutants that are inconsistent from
test to test,
• Collected with sampling devices that are not comparable with
one another,
• Collected under physical conditions that are quite dissimilar, and
» Collected using measurement and sampling techniques that are
incommens urab1e.
248
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Other generalizations concerning existing data can be made. For the
most part the data results are reported in terms of (arithmetic) average
values. However, the wide range of values reported and relatively large
standard deviations suggests that average and mean values may not be reliable
measures of central tendency. Other measures of central tendency such as
the mode, median, or geometric mean should be considered in these instances.
Much of the data that reports pollutional loadings by land use types,
geography, city, etc., uses the overall average value for a complete data
set when individual average values do not differ "significantly" from the
overall values. This can be very misleading, since "significance" is as
much dependent on the discriminating power of the statistical test being
used as well as the real difference in the average values being tested.
This high level of variability represents an underlying weakness of the
existing body of information. The inconsistencies, variation and diversity
in the data impose limitations on its usefulness and as such should be used
with caution. Although this weakness is present, the data discussed and used
in this report are the best available at this time.
DATA REQUIREMENTS
Before specific gaps in existing data can be addressed, the issue of
consistency must'be considered. Adding to the available voluminous data, more
data than is collected in a piecemeal, uncoordinated manner will only compound
current problems. Future efforts at data acquisition must be carefully planned
and executed in terms of the uses to which the data are to be applied.
Since the problem is basically one of national scope, any solution at-
tempted at other governmental levels will fall short of the goal of insuring
that the data sets collected in the future are not only commensurable with one
another, but also that the scope of other data collected is adequate for the
state-of-the-art analysis techniques. USEPA has just published a report which
establishes a handbook of accepted standards and specifications for data ac-
_quisition for urban stormwater discharges. (7.5)
Physical-Geographic Data
1. Validation of the assumption (the estimating function) that
land use distribution may be estimated by population density.
2. Validation of the techniques for estimating the percentages
of pervious and impervious area in an urban area as well as the
validation of the technique for decomposing the impervious areas
into street and non-street impervious area.
3. Validation of the methods used for estimating total curb or
gutter length.
An alternative to validating these three estimating techniques would be
to develop in each urban area of concern actual data for the three variables
being estimated. These variables are of such a nature, however, to make this
a burdensome, time consuming task, a task that would be open ended, with a
real possibility that the end results would be incomparable. Thus it appears
249
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that validation and refinement, is necessary, if the estimating techniques
would be the logical choice.
These validations should take the form of a carefully planned experi-
mental design that would take into account possible underlying influencing
parameters such as climatology, legal restrictions, and possibly terrain.
Based on this design, selected urban areas would then have the actual values
of these variables measured and compared, statistically, to the values
produced by the estimating techniques. This comparison will result in
either a validated estimating technique or guidelines for refining the
method.
Pollutional Loadings by Source
1. Streets
As reported in Section III, Application of Street Surface Contaminant
Data, calibration factors have been prepared that produced reasonable esti-
mates for individual runoff events, but only for selected pollutant types.
This calibration process applied measured annual average runoff discharge
pollutant concentrations to reported pollutant to solids relationships and
on this basis adjusted the dust and dirt (solids) values on the street.
This approach, however, neglects the possibility of error in the
analytical tool that "transports" the loadings from the street to the point
of measurement. If this tool underestimates the transport mechanism, and
loadings from other sources, such as rooftops, are also underestimated or
even ignored, then application of this calibration procedure will allocate
a disproportionate share of the pollutant loading to the street source.
This has the obvious result of placing too strong an emphasis on streets
as a point of control,
It would appear more logical to develop a standard "in-situ" method for
measuring street pollutional loadings, since once the pollutants have entered
the collection system the loadings from the different sources are mixed to-
gether. Thus, no matter how accurately the runoff pollution is measured, the
results will not trace the pollutants back to the respective source. This
method would have to be fairly simple and not require more time than local
jurisdictional people would be willing or able to give.
2. Non-Street Impervious (Rooftops, Sidewalks, Parking Lots, etc.)
The only data that have been used for estimating pollutional loadings
for this source has been the reported dustfall data. Dustfall data is not
representative of other than rooftop surfaces, and does not address possible
pollutants on these surfaces from other than dustfall sources, such as
animal droppings, decomposition of debris, etc. In light of the fact that
non-street impervious areas have been shown to be significant contributors
to the total runoff pollutant discharge it is warranted to establish
quantitatively the pollutional loadings for this source. This would pre-
ferably be done by land use categories with consideration given to where the
runoff from these sources is directed, i.e., storm or sanitary sewers, open
culverts, etc.
250
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3. Pervious Areas (Soil Loss)
By applying the Universal Soil Loss Equations to individual events, per-
vious areas have been shown to be potentially significant contributors of
sediment and other nutrients such as nitrogen and phosphorus. The use of
these equations to estimate soil loss for short term events needs to be
validated for use with small urban parcels ,or other methods should be develop-
ed.
Controlled Removal Effects
The effects of controlled removal are crucial to the evaluation of storm-
water runoff. This is especially true with the increased use of vacuum and
combined brush-vacuum street cleaning systems, as this equipment has been
demonstrated to be very efficient in removal of the finer particles that
contain most of the pollutant loadings. Thus, the equipment efficiency com-
bined with the frequency of cleaning can drastically reduce the pollutant
loadings in a given urban area.
Some street cleaning frequency data, stratified by population ranges
and climatic zones, is available. The data is sparse in some places and
additional data are needed. Data on equipment efficiency, however, is very
much lacking. This is exhibited by the wide range of values reported in the
available test data. This wide range of values is mostly caused by the fact
that efficiency is almost totally dependent on equipment conditions and
operation. Additional data will not improve this situation unless some ef-
fort is made to maintain equipment at specified minimum levels and to
standardize optimum equipment operation.
Rainfall Events
Analytical efforts to date have assumed uniform rainfall distribution
over an entire area. This assumption needs to be tested by performing
sensitivity analysis on the evaluation tools being used. This could be
done by selecting a number of areas and in each area measure the actual rain-
fall in enough locations to accurately reflect the true rainfall distribution
and scale the hypothetical statistical analysis of rainfall density by the true
rainfall pattern. If the analysis tools are in fact sensitive to the true
rainfall distributions then the methodology must be modified.
Transport Mechanism (Pollutant Removal)
Negative exponential decay functions have been used very successfully
to describe the street pollutant removal phenomenon. The function contains
a critical parameter that is dependent on the street surface characteristics.
The function has been well tested and documented.
This same function has been used to describe the non-street impervious
runoff. This is a logical application of the function since both processes
are physically analogous. However, representative values for the type sur-
face parameter are not available. Thus, the application of the function
251
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needs to be validated and from this process determine the necessary para-
metric values for rooftop surfaces.
Direct MeasuresAt Receiving Water Sites
This data will be used to verify directly several components of the
modelling effort that evaluates the stonnwater runoff phenomenon. It in-
cludes measuring runoff quantities continuously over the time period of
various types of rainfall events combined with an adequate number and type
of individual samples. The sampling plan for extracting these individual
samples must be such that the relationship between flow quantity and pol-
lutant loadings can be established. Since technology does not exist for
continuous sampling of pollutants in runoff flow, this continuity must be
approximated by judiciously selecting discrete points over the life of the
rainfall event at which to procure a sample.
252
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1. Akerlinch, G.» "The Quality of Storm Water Flow," Nordisk Hygienish
Tidskrift, 31, 1, 1950.
2. Palmer, C.L., "The Pollutional Effects of Storm Water Overflows from
Combined Sewers," Sewage and IndustrialWastes, 22, 2, 154, February, 1950.
3. "Pollutional Effects of Stormwater and Overflows from Combined Sewer
Systems - A Preliminary Appraisal," U.S. Public Health Service,
November, 1964.
4. Wischmeier, W.H., and D.D. Smith, "Predicting Rainfall-Erosion Losses
from Cropland East of the Rocky Mountains," Agricultural Handbook No. 282,
Agricultrual Research Service, U.S. Department of Agriculture, May, 1965.
5. Amy, G., "Water Quality Management Planning for Urban Runoff," USEPA
Report No. EPA-440/9-75-004, (NTIS No. PB 241 689), December, 1974.
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250), December, 1972.
8. J.L. Richards and Associates, Ltd., and Labrecque, Vezlna and Associates,
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9. Schranfuagel, P.M., "Chlorides," Commission on Water Pollution, Madison,
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10. Edison Water Quality Lab., "Environmental Impact of Highway De-Icing,"
USEPA Report No. 11040Gkk06/71 (NTIS No. PB 203 493), June, 1971.
11. Field, R.,. ET AL., "Water Pollution and Associated Effects from Street
Salting," USEPA Report No. EPA-R2-73-257 (NTIS No. PB 222 795), May,
1973.
12. "Use and Effects of Highway De-icing Salts," Legislative Research Council
Report, Commonwealth of Massachusetts, January, 1965.
13. O'Brien, J.P., ET AL., "Chemical Impact of Snow Dumping Practices,"
USEPA Report No. EPA-670/2-74-086 (NTIS No. PB 238 764), February, 1974.
253
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14. Mcllroy, A.D. ,ET AL., "Loading Functions for Assessment of Water Pollution
From Non-Point Sources," USEPA Report No. 600/2-76-151, May, 1976.
15. American Public Works Association, "Water Pollution Aspects of Urban
Runoff," USEPA Report No. 11030DNS01/69(NTSI No. PB 215 532), January,
1969.
16. "De-Icing Salts as a Source of Water Pollution," Ontario Water Resources
Commission, February, 1971.
17. Habitat School of Environment, "De-Icing Salts and the Environment,"
Massachusetts and National Audubon Societies, Lincoln, Massachusetts,
February, 1972.
18. Judd, J.H., "Lake Stratification Caused by Runoff from Street De-icing,"
Street Salting Urban Water Quality Workshop, SUNY Water Resources
Center, Syracuse University, Syracuse, N.Y., May, 1971.
19. "Runoff of De-icing Salt: Effect on Irondequiot Bay, Rochester, New
York," Bubeck, R.C., et. al., Science, (NTIS No. COM 72 10015/LK),
Vol. 1971, 1972.
20. Hunt, W.F., ET AL. , "A Study of Trace Element Pollution of Air in
77 Midwestern Cities," Paper Presented at the Fourth Annual Confer-
ence on Trace Substances in Environmental Health, University of
Missouri, June, 1970.
21. Stone, R., and H. Smallwood, "Intermedia Aspects of Air and Water
Pollution Control," USEPA Report No. EPA-600/5-74-003(NTIS lo. PB
224 814, August, 1973.
22. Dixon, J.P., "Air Conservation," Air Cpnservation Commission, APAS,
Washington, B.C., 1965.
23. Weiss, H.V., M. Korde and E. Goldberg, "Mercury in the Greenland
Ice Sheet: Evidence of Recent Input by Man," unpublished manuscript
referenced in a draft of a preliminary report of the Task Group on
Major Ocean Pollutants, for the IDOE Maine Environment Quarterly Study,
Washington, D.C., 1965.
24. Mills, A.L.j "Lead in the Environment," Chemistry in Britain, Vol. 7,
No. 14, 1972, pp. 160-162.
25. Zeeman, N., "Everyman's Garden of Pesticides," Environmental Quality,
Vol. 3, No. 2, 1972, pp. 29-33.
26. Woodruff, N.P., and F.H. Siddoway, "A Wind Erosion Equation," Soil
Science Society of America Proceedings, Vol. 29, No. 5, September-
October, 1965, pp. 602-608.
254
-------
27, Cowherd, C., ET AL.» "Development of Emission Factors for Fugitive
Dust Sources," USEPA Report No. EPA-450/3-74-037 (OTIS No. PB 238 262)
June, 1974.
28. Williford, J.W., and D.R. Garden, "Possibility of Reducing Nitrogen in
Drainage Water by on-Farm Practices," USEPA Report No. 13030ELY05/72
(NTIS No. PB 221 482), June, 1972.
29. Bartsch, A.F., "Role of Phosphorus in Eutrophication," USEPA Report
No. EPA-R3-72-001 (NTIS No. PB 228 292), August, 1972.
30. Vollenweider, R.A., "Scientific Fundamentals of the Eutrophication of
Lakes and Flowing Waters, with Particular Reference to Nitrogen and
Phosphorus as Factors in Eutrophication," OECD, DAS/C51/68-27, 1968.
31. Whitehead, H.C., and J.H. Feth, "Chemical Character of Rain, Dry
Fallout and Bulk Precipitation at Menlo Park, California, 1957 - 1959,"
Geophysical Research, Vol. 69, No. 16, pp. 3319-3333.
32. Matheson, D.H., "Inorganic Nitrogen in Precipitation and Atmospheric
Sediments," Canadian Journal of Technology, Vol. 29, pp. 406-412.
33. Schraufnagel, F.H., "Excess Water Fertilization Report," Working Group
on Control Techniques, Water Subcommittee of Natural Resources,
Committee of State Agencies, Madison, Wisconsin, 1967.
34. Stidharan, N., Ph.D., "Aqueous Environmental Chemistry of Phosphorus
in Lower Green Bay, Wisconsin," Thesis Water Chemistry Department,
University of Wisconsin, Madison, Wisconsin, 1972.
35. Uttormark, P.O., ET AL., "Estimating Nutrient Loadings of Lakes
from Non-Point Sources," USEPA Report No. EPA-660/3-74-020 (NTIS
No. PB 238 355), August, 1974.
36. Gorham, E., and J.R. Bray, "Litter Production in Forests of the World,"
Advances inEcological Research, Vol.2, 1964.
37. Heyward, F., and R.M. Barnette, "Field Characteristics and Partial
Chemical Analyses of the Humus Layer of Longleaf Pine Forest Soils,"
Bulletin of Florida Agricultural Experiment Station, Vol. 302, 1936.
38. Slack, K.V., and H.R. Feltz, "Tree Leaf Control on Low Flow Water
Quality in Small Virginia Streams," Environmental Science and Tech-
nology. Vol. 2, 1968.
39. Corle, T.S., "Composition of the Leaf Litter of Forest Trees," J. Elisha
Mitchell Science Society, Vol. 52, 1936.
40. Chase, E.S., and A.F. Ferullo, "Oxygen Demand of Leaves in Water,"
Water and Sewage Works, Vol. 105, No. 5, 1958.
255
-------
41. Ruelke, O.C., and G.M. Prime, "Preliminary Evaluation of Yield and
Protein Content of Six Hybrid Bermuda Grasses, Pensacola Behia Grass
and Pengola Grass under Three. Fertilization Regimes in North Central
Florida," Soiland CropScience Society of Florida, Vol. 28, 1968.
42. Chandler, R.F., "The Amount and Mineral Nutrient Content of Freshly
Fallen Leaf Litter in the Hardwoods Forests of Central New York,"
Journals of the American Society ofAgronomy, p. 33, 10, 1941.
43. Sartor, J.D., and G.B. Boyd, "Water Pollution Aspects of Street
Surface Contaminants," USEPA Report No. EPA-R2-72-081 (NTIS No. PB
214 408), November, 1972.
44. Kanerva, R.A., "An Overview of Maryland's Sediment Control Program,"
Maryland Water Resources Administration. ASCI National Meeting on
Water Resources Engineering, Washington, D.C., January, 1973.
45. "Methods and Practices for Controlling Water Pollution from Agricul-
tural Non-Point Sources," USEPA Report No. EPA-43Q/9-73-Q15, October,
1973.
46. Wischmeier, W.H., and D.D. Smith, "Predicting Rainfall-Erosion Losses
from Cropland East of the Rocky Mountains," Agricultural Handbook
No. 282, ARS-U.S. Department of Agriculture, May, 1965.
47. Williams, J.R., and H.D. Berndt, "Sediment Yield Computed with Univer-
sal Equation," Journal of Hydraulics Division Proceedingst ASCE,
No. 9426., p. 2087, December, 1972.
48. Renfrom, G.W., "Use of Erosion Equations and Sediment Delivery Ratios
for Predicting Sediment Yield," Paper presented at the Sediment Yield
Workshop, Oxford, Mississippi, November, 1972.
49. Vites, F.G., "Fertilizer Use in Relation to Surface and Groundwater
Pollution," Fertilizer Technologyand Use, Soil Science Society of
America, Madison, Wisconsin, 1971 (second edition).
50. Stratfull, R.F., ET AL., "Further Evaluation of De-Icing Chemicals,"
State of California Department of Transportation, Division of High-
ways, Presented at the 53rd annual meeting of the Highway Research
Board, January, 1974.
51. CONSAD Research Corporation, "A Study of the National Scope of Urban
Pesticide Runoff," A Draft Report prepared under USEPA Contract
No. 68-01-2225, November, 1974.
52. American Public Works Association, "1973 APWA Survey of Street Clean-
ing, Catch Basin Cleaning and Snow and Ice Removal Practice," Chicago,
Illinois, 1973 (unpublished).
53. Lager, J.A., ET AL., "Catch Basin Technology Overview and Assess-
ment," Report prepared under USEPA, Contract No. 68-03-0274, January,
1974.
256
-------
54. Untitled and unpublished paper prepared by William J. Murphy, American
Public Works Association, 1974.
55. Waller, D.H., "Pollution Attributable to Surface Runoff and Overflows
from Combined Systems," Atlantic Industrial Research Institute, Halifax,
Nova Scotia, April, 1971.
56. Lager, J.A., and W.G. Smith, "Urban Stormwater Management and Technology:
An Assessment," USEPA Report No. EPA-670/2-74-040 (NTIS No. PB 240 687),
May, 1974.
57. Burgess and Niple, Ltd., "Stream Pollution and Abatement from Combined
Sewer Overflows, Bucyrus, Ohio," USEPA Report No. 11024FKN11/69 (NTIS No.
PB 195 162), November, 1969.
58. Davis, P.L., and F, Borchardt, "Combined Sewer Overflow Abatement Plan,
Des Molnes, Iowa," USEPA Report No. EPA-R2-73-170 (NTIS No. PB 234 183),
April, 1974.
59. Municipality of Metropolitan Seattle, "Maximizing Storage in Combined
Sewer Systems," USEPA Report No. 11022ELK12/71 (NTIS No. PB 209 861),
December, 1971.
60. Roy F. Weston, Inc., "Combined Sewer Overflow Abatement Alternatives,
Washington, D.C." USEPA Report No. 11024EXF08/70 (NTIS No. PB 203 680),
August, 1970.
61. Rex Chalnbelt, Inc., "Screening/Flotation Treatment of Combined Sewer
Overflows," USEPA Report No. 11020FDC01/72 (NTIS No. PB 215 695),
January, 1972.
62. Wilkinson, R., "The Quality of Rainfall Runoff Water from a Housing
Estate," Journal of the Institute of Public Health Engineers, 1962.
63. Sylvester, R.O., "An Engineering and Ecological Study for the Rehabilita-
tion of Green Lake," University of Washington, Seattle, Washington, 1960.
64. Colston, N.V., "Characterization and Treatment of Urban Land Runoff>"
USEPA Report No. EPA-670/2-74-096 (NTIS No. PB 240 978), December, 1974.
65. Information on the U.S. Army Corps of Engineers survey program was
determined by a telephone conversation with Mr. Jack Rose, project
engineer for the Omaha District, in March, 1975.
66. Hinkle, G.J., "Street Cleaning Effectiveness Model," American Public
Works Association. An unpublished paper.
67. See the previous section on Street Surface Accumulation Sampling
Methods.
257
-------
68. The data reported under the 1974 URS Research Company study also include
discharge mass emission information in addition to street measurements.
69, Lee, H., ET AL., "Stoneman II Tests of Reclamation Performance, Volume
III: Performance Characteristics of Dry Decontamination Procedures,"
USNRDL-TR-336 (NTIS No. AD 228 966), U.S. Naval Radiological Defense
Laboratory, San Francisco, California, June, 1959.
70. Owen, W.L., ET AL., "Stoneman II Test of Reclamation Performance:
Volume II, Performance Characteristics of Wet Decontamination Proce-
dures," USNRDL-TR-325 (NTIS. No. AP 248 069), U.S. Naval Radiological
Defense Laboratory, San Francisco, California, July, 1960.
71. Sehmel, G.A., "Particle Resuspension from an Asphalt Road Caused "by
Car and Truck Traffic," Atmospheric Environment, Pergamon Press, Vol. 7,
(NTIS No. BNWL SA 4175 (Rev.)), Great Britain, 1973, pp. 291-309.
72. Roberts, J.W., "The Measurement, Cost and Control of Air Pollution from
Unpaved Roads and Parking Lots in Seattle's Duwamish Valley," a thesis
submitted in partial fulfillment of the requirements for the degree of
Master of Science in Engineering, University of Washington, 1973.
73. Engineering Science, Inc., "Characterization and Treatment of Combined
Sewer Overflows," USEPA Report No. EPA-670/2-750054 (NTIS No. PB 24f
299), November, 1967.
74. American Public Works Association, "Problems of Combined Sewer Facilities
and Overflows-1967," USEPA Report No. 1102012/67 (NTIS No. PB 214 469),
December, 1967.
75. Wullschleger, Richard E., ET AL., "Recommended Methodology for the
Study of Urban Storm Generated Pollution and Control," USEPA Report
No. EPA-600/2-76-145 (NTIS No. PB 258 743), Envirex, Inc., August, 1976,
76. "Urban Runoff-Quantity and Quality," ASCE, Conference at Franklin Pierce
College, Rindge, New Hampshire, August 11-16, 1974.
77. Field, R., and J.A. Lager, "Countermeasures for Pollution from Overflows:
The State-of-the-Art," USEPA Report No. EPA-670/2-74-090 (NTIS No. PB
240 498), December, 1974.
78. Weibel, S.R., R.J. Anderson, and R.L. Woodward, "Urban Land Runoff as
a Factor in Stream Pollution," Journal Water Pollution Control Federa-
tion. Vol. 36, No. 7, July, 1964.
79. Composite value for street cleaning frequency was computed on the basis
of mean data from the "1973 APWA Survey of Street Cleaning Catch Basin
Cleaning and Snow and Ice Control Practice," as reported in a previous
section of this report.
80. Roesner, L.A., ET AL., "A Model for Evaluating Runoff Quality in Metro-
politan Master Planning," Technical Manual No. 23, ASCE Urban Water
Resources Program (NTIS No. PB 234 312), April, 1974.
258
-------
81. "1970 Census Geography: Concepts, Products and Programs," Data Access
Descriptions, U.S. Department of Commerce, DAD No. 33 Series CG-3,
Washington, D.C., August, 1973.
82. "Characteristics of the Population: Number of Inhabitants," 1970 Census
of Population, U.S. Department of Commerce, Volume 1, Part A, Washington,
D.C., May, 1972.
83. "Coordination Directory for Planning Studies and Reports," U.S. Water
Resources Council, Washington, D.C., August, 1971 (as amended).
84. County and City Data Book, 1972., Social and Economic Statistics Admin-
istration, Bureau of the Census, U.S. Department of Commerce, U.S.
Government Printing Office, Washington, D.C., 1973.
85. Gross population data may be defined as the population per unit area,
where the area specified includes rights-of-way and all forms of land
use.
86. Francese, P.K., and K. Deschere, "Development of New Data Files for 1970
Census Tracts: Population Density, 1960 Comparisons Population Updates,"
Public Data Use, Vol. 1, Number 4, October, 1973.
87. Bartholomew, H., Land Uses in American Cities, Harvard University Press,
Cambridge, Massachusetts, 1955.
88. Manvel, A.D., R.H. Gustafson, and R.B. Welch, "Three Land Research
Studies," National Commission on Urban Problems, Research Report 12,
(NTIS No. PB 196 883/LK), Washington, D.C., 1968.
89. Graham, P.M., L.S. Costello, and H.J. Mallon, "Estimating of Impervious-
ness and Specific Curb Length for Forecasting Stormwater Quality and
Quantity," Journal ofthe Water Pollution ControlFederation, 47, 4,
717, April, 1974.
90. Vitale, A.M., and P.M. Sprey, "Total Urban Water Pollution Loads: The
Impact of Stormwater," Council on Environmental Quality, USGPO,
Washington, D.C., (NTIS No. PB 231 730/LK), October, 1974.
91. Springfield Sanitary District, "Retention Basin Control of Combined
Sewer Overflows," USEPA Report No. 11023-08/70 (NTIS No. PB 200 828),
August, 1970.
92. Sanborn, J.R., "The Fate of Select Pesticides in the Aquatic Environ-
ment," USEPA Report No. EPA-660/3-74-025 (NTIS No. PB 239 749),
December, 1974.
93. Holm, H.W., and M.F. Cox, "Mercury in Aquatic Systems: Methylation,
Oxidation-Reduction and Bio-accumulation," USEPA' Report No. EPA-660/3-
74-021 (NTIS No. PB 239 329), August, 1974.
259
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94. Generally abstracted from: WaterQuality Criteria, 1972, National
Academy of Science-National Academy of Engineering Committee on Water
Quality Criteria, USEPA Report No. EPA-R3-73-033 (NTIS No. PB 236
199), October, 1973.
95. Black, Crow and Eidsness, Inc., "Storm and Combined Sewer Pollution
Sources and Abatement," USEPA Report No. 11024ELB01/71 (NTIS No. PB
201 725), January, 1971.
96. Eugene A. Hickok and Associates, "Stormwater Impact Investigation for
Metropolitan Council," Minneapolis-St. Paul, Minnesota, November, 1972.
97. "Management of Urban Storm Runoff," Water Resources Engineers and
Hydrologic Engineering Center, Corps of Engineers, ASCE Urban Water
Resources Research Program Technical Memorandum No. 24, New York,
New York (NTIS No. 234 316), May, 1974.
98. Thomann, R.V., ET AT., "Mathematical Modelling of Phytoplankton in Lake
Ontario," USEPA Report No. EPA-660/3-75-005 (NTIS No. PB 241 046),
March, 1975.
Q_ Consoer, Townsend and Associates, "Detention Tank for Combined Sewer Over-
flow, Milwaukee, Wisconsin," Demonstration Project prepared for the Milwaukee
Department of Public Works, Wisconsin Bureau of Engineers, USEPA No. EPA 600/
2-75-071 (NTIS No. PB 250 427), December, 1975.
100. Field, R., and R.E. Pitt, "Water Quality Effects from Urban Runoff,"
A Paper Presented at the 1974 American Water Works Association Con-
ference, Boston, Massachusetts.
101. Untitiled and unpublished paper prepared by Robert Grim, USEPA, Wash-
ington, D.C.
102. Tsivoglov, E.G., and J.R. Wallace, "Characterisation of Stream Reaeration
Capacity," USEPA Report No. EPA-R3-72-012 (NTIS No. PB 214 649),
October, 1972.
103. Roesner, L.A., "Impact of Stormwater Runoff on Receiving Water Quality,"
Water Resources Engineers, Walnut Creek, California, June, 1973.
104. Brooks, N.H., "Dispersion in Hydrologic and Coastal Environments,"
USEPA Report No. EPA-660/3-73-010 (NTIS No. PB 226 890), August, 1973.
105. O'Brien and Gere Consulting Engineers, "Onondaga Lake Study," USEPA
Report No. 11060FAE4/71 (NTIS No. PB 206 472), April, 1971.
106. Metcalf and Eddy Engineers and Water Resources Engineers, Inc., "Recon-
naissance Study of Combined Sewer Overflows and Storm Sewer Discharges,"
Report Prepared for the Department of Environmental Service, District of
Columbia, Washington, D.C., March, 1973.
107. College of Agriculture and Life Sciences, Cornell University, "Management
of Nutrients on Agricultural Land for Improved Water Quality," USEPA
Report No. 13030DP.B (NTIS No. PB 239 328), Ithaca, N.Y., August, 1971.
260
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108. Roessler, M.A., and D.C. Tabb, "Studies of Effects of Thermal Pollu-
tion in Biscayne Bay, Florida," USEPA Reort No. EPA-660/3-74-Q14
(OTIS No. PB 239 328), August, 1974.
109. Bailey, G.W., ET AT., "Herbicide Runoff from Four Coastal Plain Soil
Types," USEPA Report No. EPA-660/2-74-017 (NTIS No. PB 235 571),
April, 1974.
110. Paris, D.F., ET AL., "Microbial Degradation and Accumulation of Pesti-
cide in Aquatic Systems," USEPA Report No. EPA-660/3-75-007 (NTIS No.
PB 241 293), March, 1975.
111. Byan, E.H., "Concentrations of Lead in Urban Stormwater," Journal of
the Water Pollution ControlFederation, Vol. 46, October, 1974,
pp. 2419-2421.
261
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APPENDIX
DATA MANAGEMENT FOR STREET SURFACE ^OLIDS ACCUMULATIONS
Three sources of data on street surface accumulations exist. These
are the results of studies by APWA for Chicago, (15) by URS Research
Company in various cities across the country (43) and by Biospherics, Inc.
for Washington, D.C. (6) Each of these studies explored the pollutional
potentials of street surface accumulations. Land-use was acknowledged
as a means of classifying and characterizing the results of field measure-
ments except in the case of the studies in Washington, B.C., where the
contribution from vehicular traffic was investigated in some detail. The
selection of sampling sites was based on the assumption that land-use effects
could be minimized. Even so, two sites in commercial areas were acknowledged
in this study as having strong land-use influences.
Some variation in field measurement technique occurred in each study.
The largest and most susceptible component to the effects of runoff was
taken to be the dust and dirt fraction of the total street accumulation.
In one case, this was defined as the fraction passing a 3.2 mm (0.125 in)
screen, (15) in another, it was assumed to be the fraction passing the
U.S. No. 6 sieve (43) and in the last, it was defined as being less than
6.35 mm (0.25 in) in size. (6)
Field measurements were generally taken by sweeping, in some instances
they were obtained by a combination of sweeping and vacuuming, and in other
cases they represented a combination of sweeping, vacuuming and flushing
with water. As may be expected, each of these sample collection methods
could yield somewhat different tresults. The most significant of these
relates to the use of flush samples.
An array of the types of samples collected in each of the aforementioned
studies is shown in Table A-l.
The most consistent sampling accomplished to date has been through
sweeping and, in some instances, vacuuming. Measurements taken on this
basis account for 90 percent of available samples collected at identified
land use sites, while 10 percent included flush sampling components.
The geographical distribution of the field observations of dust and
dirt accumulations is presented in Table A-2.
262
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TABLE A-1. DISTRIBUTION OF AVAILABLE LAND USE
RELATED SAMPLES BY MAJOR SAMPLING CHARACTERISTICS
Sample
Location
Chicago
Many Cities
Washington
Total
Sample
Type
Sweeping
Flush
Sweeping
Flush
Sweeping
Vacuuming
Flush
Sweeping
(Vacuuming)
Flush
Single-
Residential
60
—
13
8
—
— .
73
7
Multiple-
Residential
93
—
8
6
—
—
101
6
Commercial
126
—
10
7
221
141
158
21
Industrial
55
;
12
8
—
—
67
8
Total
334
—
43
28
22
14
399
42
80
' Data available in separate dust and dirt and flush fractions.
107
179
75
TABLE A-2. DISTRIBUTION OF AVAILABLE LAND USE
RELATED DUST AND DIRT SAMPLES BY GEOGRAPHICAL AREAS
441
Location
Great Lakes-
Upper Mississippi
Chicago, III..
Milwaukee, Wis.
New England-
Mid Atlantic— Ohio
Bucyrus, Oh.
Washington, D.C,
Single-
Family
Residential
62
(60)
(2)
3
(3)
(0)
Multiple-
Family
Residential
95
(93)
(2)
0
(0)
(0)
Commercial
128
(126)
(2)
22
(0)
(22)
Industrial
57
(55)
(2)
2
(2)
(0)
Total
342
(334)
(8)
27
(5)
(22)
S. Atlantic Gulf—
Lower Mississippi
Arkansas—White—Red
Texas Gulf
California—Great Basin
Upper Colorado—Lower
Colorado—Rio Grande
San Jose, Calif.
Phoenix, Az,
Pacific NW—Missouri Basin
Totals
8
(4)
(4)
0
73
6
(2)
(4)
0_
101
8
(4)
(4)
0_
158
8
(4)
(4)
0
67
30
(14)
(16)
399
263
-------
The major geographical categories shown are cited in terms of the water
resources regions identified by the Water Resources Council. Individual
cities included within the data set are also identified. The majority of
all samples have been collected in the Great Lakes area, in Chicago, Illinois,
and Milwaukee, Wisconsin. The remainder of the identified regions are
represented by considerably less field observation data. Although statistical
comparisons of aggregated data for some of the regions are possible, few
land use-related comparisons could be reasonably accomplished due to small
sample sizes or non-existent data. The addition of flush sample data would
not alter this circumstance meaningfully. Reaggregation of the data into
four major regions — Northwest, Southwest, Northeast and Southeast — would
still result in an inadequacy of data for the Northwes.t and Southeast regions.
Thus, it appears that specific comparisons on a regional basis, are not
warranted.
264
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GLOSSARY
BOD /removal efficiency: Measurement of the BOD data is used in sizing of
waste treatment facilities and for measuring the efficiency of some
treatment processes. The rate at which dissolved oxygen will be
required can also be calculated from BOD data.
catch basin: A chamber or well, usually built below grade at the curb
line of a stre'et, for the admission of surface water or drainage to
a sewer or subdrain, having at its base a sediment sump designed to
retain grit and sediment below the point of overflow.
combined sewer: A sewer receiving both intercepted surface runoff and
municipal sewage.
combined sewer overflow: Flow from a combined sewer in excess of the
interceptor or regulator (preset diversion) capacity that is discharged
into a receiving water.
confidence interval: Provides a method of stating both how close the value
of a single term is likely to be to the value of a parameter and the
chances of its being that close.
core city (central city): The major jurisdiction of 50,000 inhabitants or
more within the SMSA. In addition to the county or counties containing
such a city or cities, contiguous counties are included in an SMSA if,
according to certain criteria, they are socially and economically
integrated with the central city.
demographic: Science of the condition, general movement and progress of
population in civilized countries. The dynamic balance of a population,
expecially with regard to density and capacity for expansion or decline.
depression storage: Watershed capacity to retain water in puddles, ditches,
depressions and on foliage.
detention time: The theoretical time required to displace the contents of
a tank or unit at a given rate of discharge (theoretically defined as
volume divided by rate of discharge).
direct pollution: The processes by which urban runoff that may be accumu-
lated and collected into a separate storm sewer collection system and
may suffer impairments in its quality.
265
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direct runoff: The runoff that enters stream channels promptly by flow over
the ground surface or through the ground without entering the main water
table, or that portion of the runoff which is directly associated with
causative rainfall or snow melt.
dissolved oxygen: Usually designated as D.O. The oxygen dissolved in
sewage water or other liquid usually expressed in mg/1 or percent of
saturation.
D.O. deficit: The difference between the actual oxygen content of the water
and the saturation content at the water temperature. The process of
reoxygenation and deoxygenation go on simultaneously. If deoxygenation
is more rapid than reoxygenation, an oxygen deficit results. The amount
of dissolved oxygen at any time can be determined if the rates of re-
oxygenation and deoxygenation are known.
D.O. sag: A graphical representation of the decreasing dissolved oxygen
concentration against distance downstream. This curve is attributed
to active biological decomposition which begins immeidately after dis-
charge. This decomposition utilizes oxygen. Finally, the critical
dissolved-oxygen point, at which the rate of oxygen utilized for waste
decomposition equals the rate of atmosphere reaeration, is reached on.
this curve. Downstream from this point, the rate of reaeration is
greater than the rate of utilization and dissolved oxygen begins to
increase.
dominant soil characteristics: The following soil properties are of the
most significance: 1) sheer strength, 2) density, 3) compressibility,
4) permeability, 5) color, 6) composition (grain size, shape, plasti-
city, mineralogy), 7) structure of soil.
dry-weather flow: The flows in a combined sewer that result from domestic
sewage discharges with no significant contribution by stormwater runoff.
dust and dirt: The portion of street refuse which is smaller than 0.32 cm
(0.125 in).
erosion: (1) The wearing away of the land surface by running water, wind,
ice, or other geological agents, including such processes as gravita-
tional creep. (2) Detachment and movement of soil or rock fragments
by water, wind, ice, or gravity. (3) The spattering of small soil
particles caused by the impact of raindrops on wet soils. The loosened
and spattered particles may or may not be subsequently removed by
surface runoff.
evapotranspiration: The unit amount of water used on a given area in
transpiration, building of plant tissue, and evaporated from adjacent
soil, snow, or intercepted precipitation in any specified time.
266
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first flush: The condition, often occurring in storm sewer discharges and
combined sewer overflows, in which a disproportionately high pollu-
tional load is carried in the first portion of the discharge or over-
flow.
frequency of storm (design storm frequency): The anticipated period in
some time frame (ex. yrs.)» which will elapse, based on average proba-
bility of storms in the design region, before a storm of given intensity
and/or total volume will recur; thus, a 10 year storm can be expected
to occur on the average once every 10 years. Sewers designed to handle
flows which occur under such storm conditions would be expected to be
surcharged by any storms of greater amount or intensity.
hydrograph: A graphical representation of liquid flow versus time with
time on the horizontal axis.
hyetrograph: An intensity-time graph for rainfall derived from direct
measurements.
impervious: Not allowing or allowing only with great difficulty, the move-
ment of water. Impermeable. Waterproof.
indirect pollution: Refers to runoff as a diluent to other wastewater flows.
infiltration: The water entering a sewer system and service connections
from the ground, through such means as, but not limited to, defective
pipes, pipe joints, connections, or manhole walls. Infiltration does
not include, and is distinguished from, inflow.
interevent time: The period between points of time or events.
land use: Differentiating the spatial arrangements and activity patterns
of the urban area. From a variety of research studies it became clear
that quantityt and quality of runoff could be related to the intensity
and spatial separations of land use.
litter: Material which can be removed by sweeping street surface.
non-point discharge: Flow from an area from which pollutants are exported
in a manner not compatible with practical means of pollutant removal.
(example: croplands)
nutrients: A nutritious substance or component. A chemical element or in-
organic compound (as a nitrate) taken in by a green plant and used in
organic synthesis.
overflow: (1) The flow discharging from a sewer resulting from combined
sewage, storm wastewater, or extraneous flows and normal flows that
exceed the sewer capacity. (2) The location at which such flows leave
the sewer.
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permeability: The flowrate in gpm - cp/ft^ promoted through a granular
bed by a differential pressure equal to one foot of liquid head per
foot of bed thickness. (cp = viscosity in centipoise)
pervious: Allowing movement of water.
point discharges: Flows from a location at which pollutants are released
in quantity and concentration compatible with practical means of
pollutant removal. (example: sewage affluent)
pollutograph: A time-concentration or time-mass emission graph of a
particular pollutant carried by urban runoff.
reaeration: The process entraining air in liquids such as wastewater
effluents, streams, etc. Reaeration is proportional to the dissolved
oxygen deficit; its rate will increase with increasing deficit.
runoff: That portion of the precipitation on a drainage area that is
discharged from the area in stream channels. Types include surface
runoff, groundwater runoff, or seepage.
runoff coeffient: The fraction of the flow calculated to have reached the
ground from rain gauge data which reaches some arbitrarily chosen
downstream point. The coefficient may be measured from actual data
or estimated from the topography of the drainage area.
runoff event: A particular occurrence at which runoff occurred.
separate sanitary sewer: A sewer that carries liquid and water-carried wastes
from residences, commercial buildings, industrial plants and institu-
tions, together with minor quantitites of ground, storm and surface
waters that are not admitted intentionally.
separate storm sexier: A sewer that carries stormwater and surface water,
street wash and other wash waters, or drainage, but excludes domestic
wastewater and industrial wastes. Also called storm drain.
SMSA: Except in the New England states, a SMSA (standard metropolitan
statistical area) is a county or group of contiguous counties which
contain at least one city of 50,000 inhabitants. In the New England
states, SMSA's consist of towns and cities instead of counties. The
complete title of an SMSA identifies the central city or cities. For
a detailed description of the criteria used in defining SMSA's; see
the Bureau of Budget, Standard Metropolitan Statistical Areas: 1967,
U.S. Government Printing Office, Washington, D.C. 20402.
SWMM: Storm Water Management Model: A model developed by the EPA speci-
fically for simulation of urban quantity and quality processes.
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tertiary treatment: A third stage of treatment of sewage and other wastes,
following primary and secondary treatment, for the purpose of further
improving the quality of the treated waters by the removal or modifi-
cation of constituents which have not been removed or modified by
previous treatment steps.
universal soil loss equation: ^Predicts the short-term rates of soil loss
for localized areas. This equation takes into account the influence
of the total rainfall energy for a specific area rather than rainfall
amount. The universal equation is as follows: A = RKLSCP where A is
the average annual soil loss in tons/acre, R is the rainfall factor,
K is a soil-erodibility factor, LS is a slope length and steepness
factor, C is a cropping and management factor, and P is the supporting
conservation practice, such as terracing, strip cropping, and contouring.
urban/urbanizing: The area included within and adjacent to a municipality
or other urban place of 5,000 or more population.
wet-weather flow: A combination of storm flow as well as infiltration/
inflow which occurs as a result of a storm with or without sanitary
industrial flow. This total flow, in older or poorly constructed systems,
can be many times the dry-weather flow.
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TECHNICAL REPORT DATA
(Please read lustnictions on she reverse before completing)
t.RIPORTNO. 2.
EPA-600/2-77-064c
4. TITLE AND SUBTITLE NATIONWIDE EVALUATION OF COMBINED
SEWER OVERFLOWS AND URBAN STORMWATER DISCHARGES
Volume III : Characterization of Discharges
7, AUTHOR(S)
Manning, Martin J. , Sullivan, Richard H. ,
and Kipp, Timothy M.
9. PERFORMING ORGANIZATION NAME AND ADDRESS
American Public Works Association
Research Foundation
1313 East 60th Street
Chicago, Illinois 60637
12, SPONSORING AGENCY NAME AND ADDRESS
Municipal Environmental Res(
Office of Research and !
U.S. Environmental Prote(
Cincinnati, Ohio
2arch Labor atory ~i5 **
)evelopment
:tion Agency
45268
3. RECIPIENT'S ACCESSION-NO.
5. REPORT DATE
August 1977 (Issuing Date)
6. PERFORMING ORGANIZATION CODE
8. PERFORMING ORGANIZATION REPORT NO.
10. PROGRAM ELEMENT NO.
1BC611
1 1 . CONTRACT/O4MAM: NO.
68-03-0283
13. TYPE OF REPORT AND PERIOD COVERED
FINAL
14. SPONSORING AGENCY CODE
EPA/ 600/1 4
is. SUPPLEMENTARY NOTES Project Of ficer: , Richard Field, (201) 321-6674, (8-340-6674).
See also EPA-600/2-77-064a, Volume I, "Executive Summary," and EPA-600/2-77-064[b] ,
Volume 11, "Cost Assessment and Impacts."
IS. ABSTRACT
An analysis was made of existing data to charaterize the pollutional strength of
urban stormwater runoff and combined sewer overflows. Published and unpublished data
were evaluated.
Extensive evaluation was made of census track data to develop data concerning
land use and population densities in urban areas to assist modelling of urban storm-
water discharge.
Utilizing the developed data, an analysis of receiving water impacts was made.
It was found that much of the available data was developed with consideration
of the quantity of flow at the time quality was being considered. A wide variety of
methods used to sample flows further complicates the use of much reported data.
The estimated runoff pollutional contributions were found to exceed any contri-
buitions of treated sanitary flows at the time of a storm event. Thus, runoff pol-
lution can govern the quality of receiving water due to the shock effect and long
term buildup of solids.
This report is submitted in partial fulfillment of EPA Contract 68-03-0283 by
the American Public Works Association.
i
17. KEY WORDS AND DOCUMENT ANALYSIS
t. DESCRIPTORS
Water pollution, Combined sewers
18. DISTRIBUTION STATEMENT
RELEASE TO PUBLIC
b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group
Separated sewers, Urban drainage,
Urban runoff, Water pollution 13B
control, Water pollution effects,
Pollution sources, Urban storm-
water runoff, Storm sewer
discharges, Combined sewer over-
flows, Receiving water impacts
19. SECURITY CLASS (This Report) 21. NO. OF PAGES
UNCLASSIFIED 290
2O. SECURITY CLASS (This page) 22. PRICE
UNCLASSIFIED
EPA Form 2220-1 (9-73)
270
4 U.S. COYBWUDiT PRISTIHG WTO 197*-7 57-140/1319
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