Photo Credit: WSDOT Catch Basin Effectiveness Study Jene Colton, - - PowerPoint PPT Presentation

Photo Credit: WSDOT

Catch Basin Effectiveness Study

Jenée Colton, King County Stormwater Work Group meeting November 14, 2018

How can we use WW catch basin I&M records to inform inspection frequency needs?

Steps

Recommendations ID Drivers Analysis Compile Info

Surveys Answer ered ed Supplied Da Data

Thurston and Whatcom County submitted surveys

Loa Loaded i in Database

Survey Highlights

Less Frequent Circuit 100% Cleaning Standard

Catch Basin Inspection Schedules

Uncommon

Catch Basin Definitions

Data Analysis

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Kalama, WA Photo Credit: Joe Mabel

• Sump dimensions
• Contributing areas
• GIS delineation
• Land acreage

Grate Inlet

Outlet

Invert – Outlet Pipe Top of Solids Bottom of Sump

SUMP

Drainage Area for CB 1 Drainage Area for CB 2 Drainage Area for CB 3

Steps

Recommendations ID Drivers Analysis Compile Info

Detour

CB Z

Data Quality Issues

• C Y

Things that make you go hmmm…..

• 50
• 30
• 10

10 30 50 70 90 110 130 150 500 1000 1500 2000 2500

% of Sump

Days

Everett King County Tacoma

20 40 60 80 100 120 Jan-10 Aug-10 Feb-11 Sep-11 Apr-12 Oct-12 May-13 Nov-13 Jun-14

Percent Full

Inspection Dates

Each color is different CB

CB Z

Confidence Tiers Low – less confidence High – more confidence

• C Y

5% 7.5% 18% 14% 4% 34% 22% Everett Kent King County SPU MS4 SPU CSO Tacoma WSDOT

5 10 15 20 25 30 35 40

9.7% 9.2% 51%

10 20 30 40 50 60

Everett King County Tacoma

Percent of CBs Failing Within 2 Years: Low Confidence Tier Data

High Confidence

CB Z

Clarifications on Alternative Schedules

• C Y

CB Z

Definition of a Circuit

• CB Y
• CB Z
• CB X
• CB W

100% Cleaning Less Frequent and Circuit Approach

CB Z CB Y CB X

CB Z

Less Frequent

• CB Z
• CB X
• CB W
• No Ecology approval necessary
• Documentation of proposed schedule

based on 2 x # years

• Circuits based on land use, traffic density,

etc…similar maintenance needs

Marysville Circuits

• Implement/tighten data quality control (QC) protocols

Recommendations to Permittees

• Implement/tighten data quality control (QC) protocols
• Migrate data collection and management to integrated digital system.

Recommendations to Permittees

• Implement/tighten data quality control (QC) protocols
• Migrate data collection and management to integrated digital system.
• Consider less frequent inspection schedule with own data.

Recommendations to Permittees

• Implement/tighten data quality control (QC) protocols
• Migrate data collection and management to integrated digital system.
• Consider less frequent inspection schedule with inspection data.
• Revisit the definitions of a circuit.

Recommendations to Permittees

Recommendations to Ecology and SWG

• Standardize the definition of a catch basin to improve use of

inspection data.

Recommendations to Ecology and SWG

• Standardize the definition of a catch basin to improve use of

inspection data.

• Conduct field study of CB dynamics to allow for long-term, science-

based prediction of CB sediment accumulation.

Acknowledgements

King County Blair Scott Mark Preszler Nick Hetrick Brent Dhoore Doug Navetski Osborn Consulting Inc. Diana Hasegan Laura Ruppert

Technical Advisory Committee Angela Gallardo (Kitsap County) Laura Haren (City of Kent) Grant Moen (City of Everett) Kate Rhoads (City of Seattle) Cardno Jonathan Ambrose SAM Coordinator Brandi Lubliner

• 20

20 40 60 80 100 120 140 160 500 1000 1500 2000

% Sump Full Days Since Cleaning

Everett King County Tacoma

• Log. (Everett)
• Log. (King County)
• Log. (Tacoma)

20 40 60 80 100 120 140 500 1000 1500 2000 2500

% Sump Full Days Since Cleaning

Everett King County Tacoma

• Log. (Everett)
• Log. (King County)
• Log. (Tacoma)