Transcript Agenda - Welcome - Sewer Authority Mid

Wet Weather Flow
Management Program
Overview
Sewer Authority Mid-Coastside
Board Meeting
January 22, 2007
sam599i1.ppt
Presentation Outline
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History of Wet Weather Management Program
Recommended projects
Completed projects
Current activity
System
Model
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Constructed using EPA
SWMM 5
Models sewer basins,
pump stations, force
mains, gravity sewer,
storage basins
Calibrated to
measured flows using
measured rainfall
Used to project design
storm flows
Wet Weather Management
Program - Timeline
1997
Program
Initiated
Capacity
Study
2002
1998
Flow
Monitoring
Study
1999
Facility
Plan Study
2000
Peer
Review
2001
Improvements to
Member Agency
Collection Systems
Updated
Facility
Overflow at
Plan
Montara 12/29/03
2003
2004
2005
Value Engineering Session
for Portola Pump Station
2006
Flow
Portola Pump
Improvements Montara Pump
to Member Station/Storage Monitoring Station Storage
03/04
Alternatives
Basin
Agency
Evaluated
Completed
Collection
Systems
sam107ws1.ppt
2007
Parallel
Forcemain
Evaluation
Previous Studies
1. Intertie Pipeline System Capacity Evaluation - Phase I
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Preliminary Evaluation of Existing Facility
Assumed Wet Weather Flows
2. Intertie Pipeline System Capacity Evaluation - Phase II
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Measured Actual Flows
Estimated Design Flows for 5 Year Storm
3. Wet Weather Flow Management Program Facility Plan
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sam107ws1.ppt
Develop Capital Improvements Program
Estimate Costs
How Wet Weather Flows
Can Enter a Sanitary Sewer
Infiltration
and Inflow
Inflow
Dry Weather Flow
Sewer Lateral
Flow
Average Dry Weather Flow
Infiltration
Groundwater
sam599i1.ppt
0
1
2
3
4
5
days
Historical Overflow Locations
Montara
Pump
Station
Montara
Sanitary
District
Vallemar
Pump
Station
El Granada
Sanitary
District
Pacific
Portola
Pump
Station
Ocean
Princeton
Pump
Station
Junction
Structure
No. 1
Junction
Structure
No. 2
Half
Moon
Legend
Force Main
Gravity Pipeline
Reported Overflows
(1997-1998)
Bay
SAM WWTP
Half Moon
Bay Input
Half
Moon Bay
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Overflow Locations
Portola Pump Station –
Lowest Manholes
Surfer’s Beach
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Montara Pump Station
Recommended Alternative
for Control of 5-Year Storm
Montara Pump Station
4
To Storage
3
(Existing
Walker Tank)
4.6
1.7
0
PWWF
4.6
1.7
Flow
Capacity
PDWF
ADWF
MDWF
0.53
1.7
0.27
1.7
0.05
1.7
0.9
Vallemar Pump Station
5
3.3
4
3
El Granada
Sanitary
District
0.48
0
Flow
Capacity
PWWF
PDWF
ADWF
MDWF
3.3
0.9
0.58
0.9
0.28
0.9
0.06
0.9
Pacific
1.6
0.14
4.2
Junction
Structure
No. 1
Princeton Pump Station
Peak Hourly Flow (mgd)
3.1
4
PDWF
ADWF
MDWF
4.3
N/A
0.95
N/A
0.50
N/A
0.10
N/A
4.3
8
6
4
2
0
Flow
Capacity
8.5
PWWF
PDWF
ADWF
MDWF
8.5
8.5
2.75
8.5
1.38
8.5
0.28
8.5
3
To Storage
2
1
PWWF
Flow
Capacity
3.1
1.6
PDWF
ADWF
MDWF
0.69
1.6
0.33
1.6
0.07
1.6
Moon
Bay
Wastewater Treatment Plant
Legend
Force Main
Gravity Pipeline
Hydraulic Capacity (mgd)
Flow (mgd)
MDWF =Minimum Dry Weather Flow
ADWF = Average Dry Weather Flow
PDWF = Peak Dry Weather Flow
PWWF =Peak Wet Weather Flow
(5 yr, 6 hr storm)
Storage Basin (vol in MG)
1.4
4.6
Projected Peak Flows (mgd)
Peak Hourly Flow (mgd)
20
15
2.8
0.35
10
5
0
Flow
Capacity
PWWF
PDWF
17.8
15
5.5
15
ADWF
2.75
15
MDWF
0.55
15
10
SAM WWTP
To Storage
15
Half Moon Bay
Junction
Structure
No. 2
Half
0
sam107ws1.ppt
PWWF
Portola Pump Station
Ocean
5
1
10
(New
Storage)
1
2
Flow
Capacity
To Storage
2
3
0
Montara
Sanitary
District
2.6
2.4
4
Peak Hourly Flow (mgd)
Peak Hourly Flow (mgd)
Part of El Granada
5
Phase I Improvements
Phase II Improvements
0.51
1
Peak Hourly Flow (mgd)
2
Peak Hourly Flow (mgd)
Peak Hourly Flow (mgd)
5
9.3
8
6
4
2
0
Half
Moon Bay
Flow
Capacity
PWWF
PDWF
ADWF
MDWF
9.3
N/A
2.75
N/A
1.38
N/A
0.28
N/A
Recommended Project
Modify Existing
Storage Basin at MSD
Upgrade Montara
Pump Station
Montara
Pump Station
Vallemar
Pump Station
(add VDF's)
Construct New
Storage Basin and
Pump Station
(location to be determined)
Construct New
Storage Basin and
Pump Station
Upgrade Portola
Pump Station
Princeton
Pump Station
(add VDF's)
Portola
Pump Station
Junction
Structure No. 1
(Upgraded)
Junction
Structure No. 2
(Upgraded)
Scale 1”=3200 ft
Legend
Construct New
Parallel Force Main
Existing
Force Main
Gravity Pipeline
Pump Station
Phase I Improvements
Upgraded Pump Station
Upgraded Junction Structure
New Storage Basin and Wet Weather
Pump Station (Phase II)
Phase II Improvements
Upgraded Pump Station
New Storage Basin and Wet Weather
Pump Station (Phase II)
sam107ws1.ppt
SAM WWTP
Modify Primary
Clarifier No. 4 and
Aeration Basin
No. 4 for Storage
Phase I Improvements
IMPROVEMENT
Storage Basin
 • Montara
(Walker Tank)

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BENEFIT
• Reduce overflows at
Montara Pump Station
• Portola Pump Station
and Forcemain Expansion
• Eliminate overflows at Portola
Pump Station up to 5-yr storm
• SAM WWTP Storage Basin
(Primary Clarifier #4,
Aeration Basin #4)
• Eliminate overflow at
WWTP from Half Moon Bay
up to 5-yr storm
• Vallemar and Princeton
Pump Station Upgrades
(VFD’s only)
• Increase efficiency of both
pump stations, provide smooth
operation of intertie pipeline
system
• Monitor wet weather flows
• Possible reduction in Phase II
Improvements
Phase II Improvements
IMPROVEMENT
BENEFIT
• Upgrade Montara Pumps
• Eliminate overflows at
• Storage and wet weather
• Eliminate potential future
• Storage and wet weather
• Eliminate potential future
pump station at Vallemar
Pump Station
pump at Princeton Pump
Station
sam107ws1.ppt
Montara Pump Station up
to the 5-yr storm
overflows at Vallemar Pump
Station up to the 5-yr storm
overflows at Princeton Pump
Station up to the 5-yr storm
Montara Pump
Station Improvements
Montara Pump Station
Pumps
Abandoned Walker Tank to Be Used
for Wet Weather Flow Storage
sam107ws1.ppt
Montara Pump
Station Site Plan
Pump
Station
Storage
Basin
Pump
Station
Storage
Basin
Influent Flow to P.S.
Effluent Flow from P.S.
Influent/Effluent Flow in Storage Basin
sam107ws1.ppt
Project Results
Additional Analysis of Alternative 1A
Wet Weather Flow Management Plan Facility Plan Update
Sewer Authority Mid-Coastside
Board Meeting
January 24, 2005
SAM304i1-6851.ppt / 15
Rainfall Statistics
Design
Design Storm 6-Hour
Storm
Probability
Rainfall
Recurrence
In Any
Volume
Interval (Yrs) One Year
(inches)
6-Hour
Peak
Intensity
(in/hr)
24-Hour
Rainfall
Volume
(inches)
24-Hour
Peak
Intensity
(in/hr)
12/29/03
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1.62
0.35
2.96
0.50
1
99%
1.25
0.54
2.35
0.61
2
50%
1.60
0.69
3.00
0.78
5
20%
2.00
0.86
4.00
1.04
10
10%
2.40
1.03
4.50
1.17
25
4%
2.80
1.20
5.50
1.44
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SIMILAR PEAK, BUT SMALLER VOLUME
Alternatives Analysis
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Two Alternatives Modeled
10-year, 6-Hour Design Storm Used
Alternatives included:
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sam107ws1.ppt
Alternative 3A: New Storage Basin at Portola
Alternative 3B: New Parallel Force Main from
Portola
Alternative 3A:
10-Year, 6-Hour
Rainfall Event
Montara
Sanitary
District
Montara
PS &
Storage
Basin
2.3
2.3
0.5 (storage volume used - MG)
1.9
1.0
Vallemar
PS
Princeton
PS
2.2
El Granada
Sanitary
District
1.5
3.7
3.1
• Storage at Portola PS
2.1
0.6
Portola
PS &
Storage
Basin
MG Storage Needed
4.5
Half Moon
Bay
14.6
WWTP
10.3
(Flows enter at 4 locations)
sam107ws1.ppt
Alternative 3A:
Storage
Hydrographs
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sam107ws1.ppt
10-Year, 6-Hour
Storm
Fully utilizing Storage
at Montara PS
0.6 MG Storage
Needed at Portola
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Preliminary Cost Comparison of
Wet Weather Flow Storage
Alternatives – Portola Pump Station
Item
Total Construction Cost
Engineering, Legal, and Administration
Reserve for Change Orders
Project Subtotal
Land Acquisition
Total Project Cost
sam107ws1.ppt
Alternative 1A
0.2 MG Buried
Storage Tank
$1,074,000
Alternative 3A-1 Alternative 3A-2
0.6 MG Rectangular 0.6 MG- Circular
Storage Tank
Storage Tank
$2,782,000
$2,870,000
193,000
54,000
501,000
139,000
517,000
144,000
$1,321,000
$3,422,000
200,000
$200,000
$3,531,000
200,000
$1,521,000
$3,622,000
$3,731,000
sam107ws1.ppt
Alternative 3B Model Results
sam107ws1.ppt
Alternative 3B:
10-Year, 6-Hour
Rainfall Event
Montara
Sanitary
District
Montara
PS &
Storage
Basin
2.8
2.3
0.5 (storage volume used - MG)
2.3
1.0
Vallemar
PS
Princeton
PS
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Storage at Portola
New Parallel 14”
Force Main
Storage at WWTP
2.4
El Granada
Sanitary
District
1.5
3.9
3.8
0.7
Portola
PS &
Storage
Basin
0.03 MG Storage Needed
7.4
New 14” Force
Main
0.10 MG Storage Needed
1.3
15.0
WWTP
10.3
Half Moon
Bay
(Flows enter at 4 locations)
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Alternative 3B:
Storage
Hydrographs
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sam107ws1.ppt
10-Year, 24-Hour
Storm
Fully utilizing Storage
at Montara PS
0.03 MG Storage
Needed at Portola
0.10 MG Storage
Needed at WWTP
Proposed Forcemain Location
Coronado & Highway 1
Looking South
Junction Box 2
sam107ws1.ppt
Looking South along Highway 1
Existing Wet Weather
Facilities at SAM WWTP
Oversized Secondary Clarifiers to Handle
Peak Wet Weather Flow to 15 mgd
Expanded Influent Pump Station
SAM WWTP Improvements
sam107ws1.ppt
SAM WWTP Improvements –
Wet Weather Storage Basins
Conversion of Primary Clarifier No. 4
Conversion of Aeration Basin 4