1. CITY OF PORTLAND -
COMBINED SEWER OVERFLOW
MONITORING AND REPORTING
USING FME TO PROCESS RAINFALL DATA TO ASSESS SYSTEM
PERFORMANCE AND VERIFY COMPLIANCE WITH REGULATORY
REQUIREMENTS

2. PORTLAND’S
CSO SYSTEM
Treatmen
t Plant
Collection
System
Collection
System
Collection
System
Collection
System
CSO
System
• Collection system conveys
combined flow to major
trunks & interceptors
• Diversion structures allow
excess flow to enter the CSO
Control System (drop shafts,
tunnels, and pump stations)
• Both systems are managed
by WWTP Operators to safely
convey flow to the WWTP
where it is treated and
discharged.
• Flow that exceeds system
capacity is discharged to the
Willamette River and/or
Columbia Slough

3. NPDES REQUIREMENTS
• OVERFLOWS ARE ALLOWED IF – AND ONLY IF – RAINFALL AMOUNTS EXCEED A DEFINED STANDARD
• COLUMBIA SLOUGH: 5-YEAR WINTER, 10-YEAR SUMMER
• WILLAMETTE RIVER: 4-PER-WINTER, 3-YEAR SUMMER
• SEASONAL DEFINITIONS
• WINTER: NOV – APRIL
• SUMMER: MAY – OCTOBER
• SEASONAL STORM DIFFERENCES ARE SET TO MINIMIZE HUMAN CONTACT (E.G. PEOPLE ARE MORE LIKELY TO BE IN
OR AROUND THE WATER IN SUMMER MONTHS)
• COLUMBIA SLOUGH STANDARDS ARE MORE STRICT DUE TO THE ENVIRONMENTAL SENSITIVITY OF THE SLOUGH
SYSTEM
15 min 30 min 1 h 2 h 3 h 6 h 12 h 24 h 48 h
4-Per-Winter
Storm 0.10 0.15 0.24 0.34 0.44 0.65 0.89 1.19 1.53
3-Year Summer
Storm 0.23 0.30 0.40 0.52 0.60 0.85 1.10 1.41 2.12
15 min 30 min 1 h 2 h 3 h 6 h 12 h 24 h 48 h
5-Year Winter 0.36 0.47 0.43 0.62 0.8 1.21 1.81 2.51 3.26
10-Year Summer
Storm 0.30 0.40 0.51 0.70 0.85 1.25 1.68 2.06 3.15
Willamette River Design Storms
Columbia Slough Design Storms

4. INTRO TO ANALYSIS
• PORTLAND HAS OVER 40 RAIN GAUGE STATIONS INSTALLED ACROSS THE
METRO AREA, PARTICULARLY THE CSO SYSTEM BASIN
• DYNAMIC NATURE OF PNW STORMS CAN SOMETIMES MEAN THAT RAINFALL
INTENSITY IS NOT UNIFORM THROUGHOUT THE CSO SYSTEM BASIN
• NPDES PERMIT COMPLIANCE IS BASED ON THE AVERAGE RAINFALL THAT FALLS
OVER THE BASIN
• SOMETIMES RAIN GAUGES ARE MOVED, TEMPORARILY OFFLINE, OR ARE
REPORTING INCORRECT DATA. THIS PROCESS NEEDS TO SEAMLESSLY ACCOUNT
FOR THAT.
• THE OBJECTIVE OF THIS ANALYSIS IS TO RELIABLY DETERMINE THE AVERAGE
RAINFALL IN THE CSO SYSTEM BASIN

5. STORM EVENT ANALYSIS REQUIREMENTS
• DATA
REQUIREMENTS
• RAIN GAUGES
• THIESSEN
POLYGONS
• BASIN
BOUNDARIES
• STORED
PROCEDURE
• LOG FILE

6. WILLAMETTE CSO BASIN

7. COLUMBIA SLOUGH CSO BASIN

8. FME WORKSPACE INTRO
Insert Mandatory Super-Complex FME Workbench Here

9. NEAREST RAIN
GAUGES
BOOKMARK
• LOAD RAIN GAUGES
• FILTER FOR ACTIVE RGS
• REMOVE UNNEEDED ATTRIBUTES
• USE [NEIGHBORFINDER] TO GET
THE NEAREST 3 RGS & ADD THEM
TO A LIST
• EXPLODE THE LIST TO CREATE 3
ATTRIBUTES (FIRST_RG,
SECOND_RG, THIRD_RG)

10. SQL BOOKMARK
LOTS GOING ON HERE
• START WITH [CREATOR]
• GET THE CURRENT TIME AND SET IT TO BE THE PROCESS STOPTIME
• READ INTO THE LOG FILE (MORE LATER) FOR THE PROCESS START
TIME
• USE [FEATUREMERGER] TO COMBINE THE START AND STOP
ATTRIBUTES
• USE [ATTRIBUTEMANAGER] TO CONVERT THE TIMESTAMP INTO
SOMETHING SQL SERVER CAN READ
• USE [SQLEXECUTOR] TO CALL ON A STORED PROCEDURE THAT
RETRIEVES 15 MINUTE RAIN DATA FOR ALL RAIN GAUGES IN THE
CITY
• 2 PART PROCESS: CONTINUE PROCESSING & MANAGE LOG FILE
• LOG FILE:
• GET THE MAX DATE FROM THE OUTPUT, FORMAT IT, THEN
UPDATE THE LOG FILE
• MAIN PROCESS
• [ATTRIBUREMANAGER] TO CLEAN NAMES UP,
[DATEFORMATTER] TO GET IT TO AN EXCEL-FRIENDLY
FORMAT
• [TESTER] TO FILTER FOR RGS THAT ARE DOWN OR DO NOT
HAVE A SENSOR PRESENT
• [ATTRIBUTEMANAGER] TO GET ATTRIBUTES NAMED
CONSISTENTLY

11. BAD RG DATA
BOOKMARK
• FROM THE [TESTER], USE
[FEATUREMERGER] TO ADD THE
NEAREST 3 RGS TO THE BAD RG
RECORDS
• THEN USE [FEATUREMERGER]
AGAIN TO TRY AND GET GOOD
RAIN DATA FROM THE NEAREST
RG
• IF DATA IS GOOD (THERE IS A
MATCH) THEN MOVE THIS RECORD
BACK INTO THE ‘GOOD’ RG DATA
STREAM
• OTHERWISE REPEAT THIS PROCESS
2X WITH THE SECOND AND THIRD
RGS

12. CALCULATE AREAL WEIGHTS
BOOKMARKS
• LOAD THE THIESSEN POLYGONS AND THE SEWER BASINS.
• THIESSEN: CALCULATE AREA
• BASINS: [TESTFILTER] TO SELECT THE BASINS THAT CONTRIBUTE TO EACH SERVICE AREA
• [AGGREGATOR] DISSOLVES THE BASINS TO CREATE A SINGLE FEATURE
• [AREACALCULATOR] GETS THE TOTAL SERVICE AREA
• [CLIPPER] CLIPS THE THIESSEN POLYGONS TO THE TOTAL SERVICE AREA
• [AREACALCULATOR] THEN CALCULATES THE NEW, CLIPPED AREA CONTRIBUTION EACH RG HAS TO THE
SERVICE AREA
• [EXPRESSIONEVALUATOR] CALCULATES THE % CONTRIBUTION EACH RG HAS TO THE SERVICE AREA
• [ATTRIBUTEMANAGER] DOES CLEANUP BEFORE MOVING ON

13. CALCULATE WEIGHTED AVERAGE RAIN BOOKMARKS
• [FEATUREMERGER] COMBINES THE GOOD RAIN DATA, BAD (BUT FIXED) RAIN DATA, AND THE
THIESSEN % DATA INTO ONE RECORD FOR CALCULATION
• [EXPRESSIONEVALUATOR] MULTIPLIES THE RAIN DATA X {PCT_NET_RG_AREA} TO GET
AREAL_WEIGHT_RAIN
• [AGGREGATOR] ACCUMULATES RECORDS BASED ON TIMESTAMP TO A SINGLE WEIGHTED RAIN
RECORD
• [ATTRIBUTEREMOVER] DOES CLEANUP
• [SORTER] GETS THE DATA READY FOR EXCEL
• [FEATUREMERGER] IS USED WITH A LOOKUP TABLE TO GET THE XLSX_ROW_ID VALUE NEEDED TO
UPDATE THE DATA IN THE DESTINATION EXCEL FILE

14. OUTPUT
• WRITE TO 2 EXCEL WORKSHEETS;
ONE FOR EACH SERVICE AREA
(BECAUSE THEY HAVE DIFFERENT
EVENTS & DESIGN STORM
REQUIREMENTS)
• USE THE XLSX_ROW_ID AS THE ROW
NUMBER ATTRIBUTE.
• CONCLUSION
• WORKBENCH GETS RAIN DATA FROM
THE SERVER AND CALCULATES THE
WEIGHTED AVERAGE RAINFALL
• LOG FILE FACILITATES FASTER
PROCESS TIME BY ONLY GETTING
THE DATA SINCE THE LAST UPDATE.
A FULL YEAR OF DATA TAKES 2+
HOURS TO PROCESS (42 RGS AT 15
MINUTE INTERVALS = ~1.5M
RECORDS). THIS NOW TAKES 2-4
MINUTES.

15. EXCEL STORM
EVENT COUNTER
• NEED TO MOVE PROCESSING OVER TO
EXCEL BECAUSE THERE IS A
SIGNIFICANT AMOUNT OF DYNAMIC
INTER-RECORD ANALYSIS THAT NEEDS
TO OCCUR.
• FME DOES HAVE MULTIPLE FEATURE
ATTRIBUTE CAPABILITIES BUT THE
NUMBER OF FEATURES IS FIXED. WE
NEED IT TO BE DYNAMIC
• THE WORKSHEETS THAT FME WRITES
RAIN DATA TO ARE FORMATTED WITH
COLUMNS AND FORMULAS THAT HELP
DEFINE WHEN A STORM STARTS AND
STOPS
• IT IS KIND OF A COMPLEX AND PERMIT-
DRIVEN PROCESS THAT IS USED TO SET
THIS DEFINITION.
• THIS TABLE IS REFERENCED BY THE
MAIN STORM COUNTER WORKSHEET

16. EXCEL LOGIC PROCESS