COG’s Round 8.2 Cooperative Forecast &
Regional Wastewater Flow Projections
COG staff - Presentation to WRTC
September 6, 2013
Overview
 COG’s Wastewater Treatment Plants
 Focus on Major Plants (defined as => 2 mgd)
 20 – Including both Dale Service Corp plants
 Service Area (SA) maps – being confirmed/updated
 SAs shown for Majors, though ‘Other’ still being refined
 COG’s Regional Cooperative Forecast Process
 Round 8.2 – recently adopted by COG Board
 COG’s Regional Wastewater Flow Forecast Model (RWFFM)
 Basic assumptions
 Demographic trends for Majors
 Flow projections – Unadjusted & Adjusted
 Remaining regional capacity
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COG’s Regional
Cooperative Forecast Process
 Round 8.2 Cooperative Forecast adopted by COG
Board on July 10, 2013
 Demographic projections are based on Jurisdictions’
forecasts and are within 3 percent of the
econometric model projections
 Population, employment, and households
 Demographic information is allocated from
Transportation Analysis Zones (TAZs) to the
appropriate wastewater service areas (i.e.,
sewersheds and sub-sewersheds)
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COG’s RWFFM – Basic Assumptions
 Regional model grown from original Blue Plains work
 Wastewater projections derived employment & households
and Flow Factors (not population)
 Black & Veatch updated Base Year Flows (BYF) & flow factors
for Blue Plains in 2010
 2009 BYFs are actual annual average flows
 I/I rate of 44% of incremental sanitary flow remained the same
 Used Ffx #’s for VA plants & WSSC #’s for MD plants
Table ES-2 – 2009 Approved Flow Factors
Category
Household
(gpd/unit)
Employment
(gpd/employee)
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Fairfax
County
150
WSSC
District
180
Loudoun
Water
185
30
170
Dulles
VA
NA
Vienna
VA
170
28
25
25
48
21-50
9/6/13
Demographic Projections for COG Region Served by Major WWTPs (=> 2 mgd)
Round 8.2
Significance to Bay
7.00
Chesapeake Bay overall
population – 17.5 Million
6.00
COG population
approximately 30%
COG Total
5 million
5.00
4.72
Millions
4.00
4.41
4.94
5.18
5.38
5.56
5.72
Household
4.59
Employment (includes
industrial, office, retail, &
others)
3.00
2.00
Population
1.00
0.00
2009
2010
2015
2013
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2020
Years
2025
2030
2035
2040
2033 / 20-year planning period
9/6/13
COG Major WWTPs &
‘Unadjusted’ Flow Projections (Draft)
UNADJUSTED FLOWS (mgd)
WWTP
ALEXANDRIA
ARLINGTON
BALLENGER CREEK
BLUE PLAINS
BOWIE
2009
2015
2020
2025
2030
2035
2040
36.23
37.99
40.22
42.95
45.43
47.78
49.92
26.03
26.58
29.55
32.65
34.89
36.6
37.84
39.56
5.11
5.26
5.31
5.47
5.68
5.95
6.19
6.39
298.96
315.58
332.25
348.22
362.51
375.26
388.37
2.01
2.07
2.09
2.11
2.13
2.17
2.22
3.62
3.85
3.94
3.96
3.97
3.98
3.99
3.61
5.72
5.77
6.05
6.3
6.54
6.78
7.03
7.27
0.67
0.7
0.71
0.72
0.76
0.8
0.81
0.82
6.20
6.6
6.69
6.94
7.38
8.04
8.35
8.7
13.08
13.37
15.59
17.7
19.62
21.31
22.79
24.04
2.50
2.51
2.67
2.83
2.99
3.07
3.15
3.22
5.06
5.17
5.46
5.92
6.3
6.59
6.82
6.99
10.97
10.96
11.03
11.12
11.25
11.37
11.53
11.58
40.95
42.6
44.31
46.13
47.71
49.15
50.51
296.55
2.01
BROAD RUN
DALE CITY (#1 + #8)
FORT DETRICK
FREDERICK
MOONEY
LA PLATA
LEESBURG
MATTAWOMAN
2010
36.11
NOMAN COLE
40.79
6.27
6.35
7.01
7.1
7.24
7.36
7.45
7.5
PARKWAY
22.41
22.33
23.42
24.3
25.02
25.38
25.69
26.21
PISCATAWAY
15.56
15.76
16.93
18.06
19.9
22.12
23.73
24.4
SENECA
30.33
30.71
33.81
37.08
40.05
42.71
45.1
47.29
UPPER OCCOQUAN
20.02
20.17
21.17
22.06
23.03
24.29
25.7
27.35
WESTERN BRANCH
Total Flow - Unadjusted 549.00 554.01 587.49 621.06 654.02 684.12 710.52 736.33
Total Flow - Adjusted 549.00 554.01 587.49 621.06 654.02 684.12 710.52 718.15
% Capacity (After
adjustments made)
71%
71%
76%
80%
84%
88%
92%
93%
776.1
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776.1
776.1
776.1
776.1
776.1
776.1
776.1
2040
Projected
Remaining
Remaining
Flow
Flows - After Capacity - After
CAPACITY Capacity Diversions
Adj. Made
Adj. Made
54
40
7
370
3.3
11
9.2
2
8
24
2.5
10
20
67
7.5
30
26
54
30.6
776.10
4.08
0.44
0.61
-18.37
1.08
7.01
1.93
1.18
-0.7
-0.04
-0.72
3.01
8.42
16.49
0
3.79
1.6
6.71
3.25
39.77
49.92
39.56
6.39
-40.808
9.093
15.751
347.562
Comments/Rationale
4.08
0.44
0.61
Total flow diversion per BPSA
study - District reductions part of
this figure, as well as Ffx &
22.438 Loudoun diversions
1.08 Adjusted flow assumes all
13.083
7.27
0.82
8.7
24.04
3.22
6.99
11.58
Loudoun diversions away from
BP are all routed to Broad Run in
-2.083 2040
1.93
1.18
-0.7
-0.04
-0.72
3.01
8.42
66.261
7.5
26.21
24.4
47.29
27.35
Adjusted flow assumes all Fairfax
diversions away from BP are all
0.739 routed to Noman Cole in 2040
0
3.79
1.6
6.71
3.25
718.146
55.734
93%
18.18
Unadjusted flows reflect only impact of demographic trends
Net Diff. between Total Adjust &
Unadj Regional Flows (2%)
reflects District's flow reduction
efforts at Blue Plains
9/6/13
COG Major WWTPs &
‘Unadjusted’ Flow Projections (Draft)
Total Regional Capacity
(for Majors) – 776 mgd
Unadjusted flows reflect only impact of demographic trends
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COG Major WWTPs &
‘Adjusted’ Flow Projections (Draft)
Total Regional Capacity
(for Majors) – 776 mgd
718 mgd
= 93% of
Total
Capacity
Adjusted flows reflect impact of (significant) flow reductions & flow diversions
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COG’s Region
Forward and Economy
Forward initiatives
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Next Steps
 Continue to verify with WWTP operators:
 WWTP service area maps
 Flow projections/assumptions
 Refine maps re: septic/distributed systems vs. non-
sewered areas
 Present overall/regional findings to CBPC (9/20/13)
 Region Forward
 Report on ‘percent wastewater capacity’ findings
 Overall RAC’s on WWTP Service Areas
 Flow vs. Load Capacity Analysis
 Outgrowth of work being done for Blue Plains Users
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Wrap-up
 Questions?
 Ideas?
 Additional presentations:
 COG’s Cooperative Forecast process
 COG’s RWFFM
 CBP’s use to characterize/project growth
 Many thanks for teamed effort – Mukhtar Ibrahim, Nasser
Ameen, & Lana Sindler
 Contact: Tanya Spano (202) 962-3776 / tspano@mwcog.org
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