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 Compile Info Analysis ID Drivers Recommendations

Surveys Answer ered ed Supplied Da Data Loa Loaded i in Database Thurston and Whatcom County submitted surveys

Survey Highlights

Catch Basin Inspection Schedules Uncommon Less Frequent 100% Cleaning Standard Circuit

Catch Basin Definitions

Data Analysis

https://creativecommons.org/licenses/by-nd/2.0/legalcode Photo Credit: Oregon DOT Photo: Dhs Commtech at English Wikimedia Kalama, WA Photo Credit: NoDerivs 2.0 Generic Photo Credit: Joe Mabel License://creativecommons.org/licenses/by-nd/2.0/legalcode

Grate • Sump dimensions Inlet • Contributing areas • GIS delineation • Land acreage Outlet Invert – Outlet Pipe Top of Solids SUMP Bottom of Sump

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

Steps Detour Compile Info Analysis ID Drivers Recommendations

Data Quality Issues CB Z C Y •

Things that make you go hmmm….. 150 130 110 90 % of Sump 70 Everett 50 King County Tacoma 30 10 -10 0 500 1000 1500 2000 2500 -30 -50 Days

120 100 80 Percent Full 60 Each color is different CB 40 20 0 Jan-10 Aug-10 Feb-11 Sep-11 Apr-12 Oct-12 May-13 Nov-13 Jun-14 Inspection Dates

Confidence Tiers Low – less confidence CB Z High – more confidence C Y •

Percent of CBs Failing Within 2 Years: Low Confidence Tier Data 0 5 10 15 20 25 30 35 40 High Confidence Everett 5% Tacoma Kent 51% 7.5% King County 18% King County 9.2% SPU MS4 14% Everett 9.7% SPU CSO 4% 0 10 20 30 40 50 60 Tacoma 34% WSDOT 22%

Clarifications on Alternative Schedules CB Z C Y •

Definition of a Circuit Less Frequent and 100% Cleaning Circuit Approach CB W CB X • • CB Z CB X CB Y CB Z CB Y CB Z • •

Less Frequent • No Ecology approval necessary • Documentation of proposed schedule based on 2 x # years CB X CB W • • CB Z • Circuits based on land use, traffic density, etc…similar maintenance needs CB Z • Marysville Circuits

Recommendations to Permittees • 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 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 Technical Advisory Committee SAM Coordinator Blair Scott Angela Gallardo (Kitsap County) Brandi Lubliner Mark Preszler Laura Haren (City of Kent) Nick Hetrick Grant Moen (City of Everett) Brent Dhoore Kate Rhoads (City of Seattle) Doug Navetski Cardno Osborn Consulting Inc. Jonathan Ambrose Diana Hasegan Laura Ruppert

160 140 140 120 120 100 100 Everett % Sump Full Everett 80 King County % Sump Full 80 King County Tacoma Tacoma Log. (Everett) 60 Log. (Everett) 60 Log. (King County) Log. (King County) Log. (Tacoma) 40 Log. (Tacoma) 40 20 20 0 0 0 500 1000 1500 2000 2500 0 500 1000 1500 2000 Days Since Cleaning -20 Days Since Cleaning