“All I can say is Gulp!” Stormwater Management Planning at the Port of Longview, WA

Outline

► Overview of Port

■ Property

■ Industrial Stormwater General Permits (ISGP)

■ Corrective Actions - Treatment

► Stormwater Management Plan

■ Treatment Design - Long-term Vision and LID

■ Modeling

■ Gulp!

ISGP Sampling – 5 Sample Points

ISGP Corrective Actions

► Quarterly Stormwater Samples & Benchmarks

■ Turbidity

■ pH

■ Oil Sheen

■ Total Copper

■ Total Zinc

► Number of Exceedances

by Calendar Year

► Level 1 - Operational

Level 2 - Structural

Level 3 - Treatment (by Sept. 30 the next year)

Port’s Current Corrective Action Status

► In 2013 the Port triggered:

■ Level 3 for Turbidity

■ Level 3 for Zinc

► Port requested a Permit Modification to Extend the Deadlines to 2017

► Status of Treatment:

■ Designing for Sample Point 5

■ Analyzing for Sample Point 1

■ Anticipating for Sample Point 4

Level of Treatment Required?

Sample Point Basin Area

(Approx. Acres) Turbidity (NTU) Zinc (ug/L)

Benchmark Concentration(Goal): 25 117

Sample Results (to 2013): Maximum Conc’n -

(Percentage Reduction)

Maximum Conc’n -

(Percentage Reduction)

SP1 73 94 - (73 %) 316 - (63 %)

SP4 64 31 - (19 %) 105 - (none!)

SP5 9 736 - (97 %) 1320 - (91 %)

What about SP2 & SP3?

► Sample Points 2 and 3 have Treatment Installed and are Meeting Benchmarks

► Proprietary Media Filtration

■ Quick Solution and Pilot Test

■ Treat 1.2 acres and 0.4 acres

Port’s Treatment Design Goals

► Assume source control fully implemented

► LID – Green Port

► Reasonable Cost

■ Gravity-based, passive systems

■ Integrate with existing conveyance

■ Bioretention/Biofiltration, Wetlands

► Accommodate and adapt to tenants and other owners.

► An ongoing, long-term process …

Modeling a Complex Stormwater System

► Multiple Data Sources, Survey Dates, Datums

► Many Unknowns & Assumptions

► Flat Level Terrain, Low Grades, Backwater and Tailwater

► How to Model?

Modeling a Complex Stormwater System

► CAD

► ESRI ArcGIS

► Autodesk Storm and Sanitary Analysis

► And so on…

Treatment Area #5

► Drainage to SP5 from Berth 8, and Warehouse 8 Area

■ Log handling, bulk materials

► Use Existing Swale and Basin

► Gravity flow, Infiltration

► Outfall to Finger Slough Pond

Biofiltration versus Bioretention

► Bioretention

■ Engineered Rain Garden

■ No liner, no underdrain

■ Recharges groundwater

■ Feasibility: soils and groundwater

► Biofiltration

■ Engineered Media Filtration

■ Underdrain piping

■ Drains to surface water

■ Very Effective!

Treatment Area #5 - Bioretention

► Water Quality Diversion

► Pretreatment Basin

► Infiltration Basin

► Blend Bioretention Soil Mix Onsite

► Overflow Piping to Finger Slough

► Conceptual Cost Estimate: $320,000 (+50/-30%), ~$18,000 / Acre Treated

► Now At 30% Design – Infiltration okay, groundwater is close…

Google Maps Image

Know Your Site History Before You Infiltrate

► 1957 – Long Bell Lumber Company

13.0”/hr

3.3” /hr

Treatment Area #4A

► Drainage from Open Laydown Area Berths 5 and 6

► Existing CB and Pipes

► Relatively Clean Runoff

► Bioretention Candidate

► Conceptual Cost: $420,000 (+50/-30%)

■ ~$18,500 per acre treated

Ports, Expect the Unexpected

► Haven Energy Liquefied Propane Gas Terminal

■ Will design their own system.

■ Obtain their own ISGP coverage.

■ Meet the Port’s standards.

■ Pervious surfaces and grassed swales

■ Use Area 4A?

Treatment Area #4

► Drainage to SP4 from Berths 5, 6 and 7

► Requires pumping from Berths.

► Treatment by gravity, high groundwater.

► Discharge to the Finger Slough

► Subsurface Flow Constructed Wetland

Treatment Area #4

► Proposed Wye Track Wetland

■ Excavation, Soil Amendments, Planting

■ Inlet / Outlet Structures

► Conceptual Cost: $1,130,000 (+50/-30%)

■ ~$33,000 per acre treated

► Collection, Conveyance & Pumping from Berths 6 and 7

■ Design Complete (Almost!)

■ Estimated Cost: $2.4 million

Google Maps Image

Treatment Area #1

► 78 Acres to SP1 and the West Perimeter Ditch.

► Restricted land area and other property owners.

► Contaminated soil, poor infiltration.

► Minimal hydraulic head.

► Oldest stormwater system.

Treatment Area #1

► Evaluation of Alternatives Continues…

■ Distributed LID

■ Subsurface Flow Wetlands

■ Pump Station(s)

■ Source Control

■ Operational Changes?

► Estimated Cost: $2.3M - $5M

Treatment Area #1 - Alternatives to LID

► Potential smaller footprint and more control

■ Proprietary packaged systems

■ Engineered wastewater treatment systems

► Estimated Total Cost: $6 - $12 million

■ Plus higher O&M

► What about AKART?

Probable Cost Summary (Gulp!)

Treatment Area Acres Conceptual

Treatment Option Probable Cost

Area #1 78 To be determined… $ 2,300,000 - $ 5,000,000

Area #4A 24 Bioretention/Infiltration $ 290,000 - $ 630,000

Area #4 34 Wetland $ 790,000 - $ 1,700,000

Area #5 18 Bioretention/Infiltration $ 220,000 - $ 480,000

All Treated Area 154 Passive / Green $3,600,000 - $7,810,000

All Treated Area 154 Active / Pump & Treat $11,000,000 - $23,000,000

Questions??

AlanFlemming@KennedyJenks.com

Kennedy/Jenks Stormwater Blog