Floating Wetlands King County, Washington

Who we are Nancy Rottle - Director, University of Washington

Green Futures Research and Design Lab Mason Bowles - Senior Ecologist, Ecological Restoration

and Engineering Services Section, WLRD Matt MacDonald - Student, UW Masters of Landscape

Architecture Program; Staff Member, UW Green Futures Lab

Sally Abella – Senior Engineer, Freshwater Assessment

Group, Science and Technical Support Section, WLRD

Floating Wetlands presentation outline

•  What are floating wetlands?

•  Why do they matter?

•  How do they work?

•  Where are they already?

•  How is King County involved?

•  Where else could they be used?

What are floating wetlands? Constructed ecosystems that mimic naturally occurring wetlands

biomatrixwater.com naturalhighsafaris.com

In some cases, they are naturally occurring wetlands, e.g. bogs

Evans Creek, Redmond

What are floating wetlands? Constructed ecosystems that mimic naturally occurring wetlands

Floating Island International

British Library

Hicklin Lake, West Sea0le

Photo: Matt MacDonald

Floating frame or foam mat

Growing media

Native wetland plants

Andrea Haynes

•  Sequester carbon •  Improve water

quality

•  Create habitat

•  Tolerate fluctuating water levels

•  Can be configured to existing aquatic urban environments

Andrea Haynes

Why are floating wetlands an important new technology?

•  Improves water quality and provides habitat

•  Scalable and cost effective with minimal maintenance

•  Can be configured to existing urban and rural aquatic environments

•  Increases wetland area without requiring additional land

Why are floating wetlands an important new technology?

•  Improves stormwater pond polishing efficiencies

•  Not compromised by water level fluctuation

•  Relies upon biotic processes to manage pollutants (biofilms)

•  An innovative BMP gaining broader acceptance

Spiral Island 1, Joyxee, Mexico

What are the shortcomings of floating wetlands?

•  Lower dissolved oxygen (DO) may occur underneath mats

•  Sizing criteria still being refined

•  Organic litter needs to be removed if managing for nutrients

•  May attract waterfowl

•  More frequent stormwater pond sediment removal

What are the immediate benefits of floating wetlands?

•  Increases aquatic shading •  Traps sediments •  Competes for nutrients •  Mitigates metals and toxicants •  May control temperatures •  Contributes to food chain •  Provides habitat complexity

What are the long-term benefits of floating wetlands?

•  Shoreline protection

•  Habitat restoration

•  Beautification

•  Water quality improvement

•  Climate adaptation and mitigation

Water Quality Improvement


Biofiltration: Water Quality Improvement

Floating wetlands: •  Reduce total suspended solids (turbidity) •  Reduce total phosphorous •  Reduce ammonia •  Reduce total nitrogen •  Reduce bio-chemical oxygen demand (BOD) •  Remove heavy metals

References- tinyurl.com/FloatingWetlandsSeattle

Plant and Insect Habitat

pichost.me/1620939/

Fish Habitat


Wildlife Habitat


Shoreline Protection


Climate Adaptation and Mitigation


Beautification

Turenscape

Shade & Cover

Turenscape

BioMatrix

Shoreline Restoration

Installed

Mature

How do floating wetlands work?

tinyurl.com/FloatingWetlandsSeattle

Some Literature Reports

What do floating wetlands cost?*

•  Port of Vancouver, WA $0.85 sq. ft. •  KCDOT Lower Stensland Creek $1-14 sq. ft. •  Phytolinks $20 sq. ft. •  Biomatrix $32 sq. ft. •  Biohaven $40+ sq. ft.

*not including costs of design, permitting,

maintenance, and monitoring

Where are floating wetlands already in use?

Worldwide Distribution

Yingri Lake, Jinan, China


Queensland, Australia

SPEL Environmental

Louisiana Gulf Coast


Baltimore Harbor

The Waterfront Partnership, photo by Adam Lindquist

Baltimore Harbor Proposal

San Francisco

Andrea Haynes

Opportunities Study

Andrea Haynes

Pacific Northwest

Port of Vancouver, WA (2015)

Matt Graves

Hicklin Lake, West Seattle (2013)

Photo: Matt MacDonald

Floa>ng water quality islands in Hicklin Lake, White Center

Sally Bartley Abella Science and Technical Support Section King County Water and Land Resources Division

Where is Hicklin Lake and its islands?

|

A brief(!) history of Hicklin (Hicks, Garre0) Lake: •  Open water wetland dredged for storage capacity for golf course in the 1930s.

•  King County purchased in the 1940s and created Lakewood Park, including swim beach and fishing dock.

•  Combined sewer system split into two systems in late 1950s – old lines used for storm water and rerouted into Hicklin Lake.

•  High bacterial counts found in the 1960s beach closed recurrently; becoming permanent in 1991.

•  Flooding during winter storm events. Pump installed to control water levels; water goes to Puget Sound.

•  WDFW fish stocking ended in 1992. Dock dismantled 2012.

•  Nuisance and toxic algae concerns result in first alum treatment in 2005, followed by a second treatment in 2011. Floa>ng islands in 2013.

Floa>ng islands project – the dry details: •  Friends of Hicklin Lake asks for floa>ng islands as an alterna>ve to future alum treatments.

•  Island suitability was inves>gated: water quality benefits, habitat enhancement, costs, maintenance.

•  Funding leveraging a WDOE algae control grant with supplementary King County project funding, affording two islands of 600 a2 each and WQ monitoring for two years.

•  Biomatrix Water / Herrera Environmental selected to provide pladorms and direct installa>on in July 2013.

•  Plan>ng design by King County staff, combining sedges, rushes, and bulrush with willows and na>ve ornamentals such as Nootka Rose, Ninebark and red-‐twig dogwood. (FOHL request : make them pre0y!)

Installa>on: a community event •  King County staff and contractors, •  Washington Conserva>on Corps team, •  KC Youth Source interns, and •  University of Washington students

The lake level was LOW! Note lack of emergent vegeta>on around shoreline.

Installa>on: anchoring in place

Maintenance and lessons learned: •  Annual weeding in late spring sufficient; check-‐back in fall. •  Mortality less than 10%, mostly small sedges planted high. •  The shrubs will need to be pruned regularly. •  Blown-‐in weeds can establish quickly. •  As the plants grow, it’s harder to maintain the plants … need chest waders to get on the islands.

•  Ducks deterred by fencing, but do rest on the edges. •  Kids throw rocks! Center placement helps.

Water quality monitoring: Important dates: April 2005 first alum; May 2011 second alum; July 2013 floa>ng islands

Dynamic media columns: •  Inert material to create underwater surface area like root

systems. •  Can remove and squeeze material off to measure N and P content. •  One column from each island, June and September in 2014. •  Measurements from one column in Fall 2013 produced similar

values. •  NOTE: Observa>on of large root systems at the edges suggest

that more biofilm may be on living roots than on the columns.

Total N Total PEast island 6/10/2014 11.85 1.67

9/16/2014 66.56 10.24Increase % 562 613

West island 6/10/2014 9.94 1.379/16/2014 54.75 8.71Increase % 551 635

Total mg / media column

Metals and water quality standards:

exceeds or could exceed acute standardexceeds or could exceed chronic standard

0.50 red, bold font indicates <MDL

A745-‐1m Element 5/14/13 6/11/13 7/8/13 8/20/13 9/17/13 10/15/132013 hardness 20.3 21.4 22.1 20.8 21.2 18.5

pH 6.58 6.82 7.6 9.29 6.72 6.74 2013Deg-‐C 18.4 20.8 24.0 22.8 19.5 12.0 > chronic > acute median

Arsenic As 1.36 1.75 2.31 3.03 2.63 1.53 0% 0% 2.31Cadmium Cd 0.05 0.05 0.05 0.05 0.05 0.05 0% 0% 0.05Chromium Cr 0.38 0.34 0.37 0.31 0.40 0.44 0% 0% 0.37

Copper Cu 4.17 3.03 3.97 3.05 3.92 4.29 60% 40% 3.92Lead Pb 2.63 2.83 2.82 3.04 2.8 2.17 100% 0% 2.82

Nickel Ni 0.92 0.88 1.25 0.82 0.99 0.98 0% 0% 0.98Selenium Se 0.50 0.50 0.50 0.50 0.50 0.50 0% 0% 0.5

Silver Ag 0.04 0.04 0.04 0.04 0.04 0.04 0% 0% 0.04Zinc Zn 24.1 21.1 27.6 6.74 21.6 25.7 20% 0% 21.6

Element 5/13/14 6/10/14 7/15/14 8/19/14 9/16/14 10/14/142014 hardness 21 21.5 22.6 22.3 21.4 20.7

pH 7.79 7.31 7.24 9.26 7.38 6.18

Deg-‐C 17.8 21.4 25.4 23.4 18.6 16.1 > chronic > acute median change

Arsenic As 0.847 1.16 1.72 2.14 2.18 1.83 0% 0% 1.83 <Cadmium Cd 0.05 0.05 0.05 0.05 0.05 0.05 0% 0% 0.05

Chromium Cr 0.33 0.29 0.23 0.23 0.33 0.32 0% 0% 0.29 <Copper Cu 3.65 3.08 2.86 3.53 3.13 3.10 60% 0% 3.10 <Lead Pb 1.23 1.3 1.31 1.24 1.95 1.69 100% 0% 1.31 <Nickel Ni 0.804 0.78 0.66 0.67 0.62 0.765 0% 0% 0.67 <Selenium Se 0.50 0.50 0.50 0.50 0.50 0.50 0% 0% 0.5Silver Ag 0.04 0.04 0.04 0.04 0.04 0.04 0% 0% 0.04

Zinc Zn 25.9 7.6 10.8 8.43 9.83 9.27 0% 0% 9.27 <

% above standardJune-‐October

June-‐October% above standard

Future of the project and the islands: •  Recently catalogued as a KC stormwater facility. •  Remove tenacious reed canary grass plant: drowning and black

plas>c? •  Monitor water quality into the near future to clarify direc>onal

changes from year-‐to-‐year variability. •  Follow biofilm nutrient sequestra>on on dynamic media columns. •  Sample root mass for biofilm nutrients? •  Evaluate planted species for ul>mate size, growth rate, and ease

of maintenance. •  Evaluate island structural components for longevity and durability. •  Add to our Frisbee and rock collec>ons.

KCDOT Novelty Hill Road Improvement Project

Lower Stensland Creek Wetland Mitigation

•  Created 2,912 linear feet of stream channel and 3.45 acres of riverine wetlands

•  Installed 3.3 acres of native riparian and wetland buffer vegetation

•  Created 0.25 acres of permanent open water •  Deployed 1800 sq. ft. of floating wetlands

(.04 acres)

Lower Stensland Creek, Redmond, WA

Stensland Pond Preliminary Temperature AnalysisJuly 11, 2007

00:00:00 06:00:00 12:00:00 18:00:00 00:00:00

TEM

PE

RA

TUR

E (o C

)

14

16

18

20

22

24

26

28

30

32Stensland CreekWest Pond UpperWest Pond LowerModel - No shade Model - 25% Shade Model - 50% Shade

QUAL2K Temperature Model

•  Model predicted that project with no shade would increase downstream temperatures by 4.3 oC at the outlet of the pond network for daily average temperatures

•  With 25% shade, model predicted increases of 0.8oC •  With 50% shade, model predicted decreases of 3.1oC

MacDonald Floating Wetlands Thesis, Redmond, WA

(in progress)

Thesis Goals sampler

•  Design floating wetlands to mimic a greater array of wetland conditions and habitats

•  Test Pacific Northwest plants for suitability

•  Design FWs for lasting nutrient and carbon storage

First Prototype

Matt MacDonald

Shoreline Edge

Matt MacDonald

Emergent Vegetation

Matt MacDonald

Fully Submerged

Matt MacDonald

Fully Submerged

Matt MacDonald

Fully Submerged

Matt MacDonald

Overhanging Canopy

Matt MacDonald

Overhanging Canopy

Matt MacDonald

Overhanging Canopy

Matt MacDonald

PNW Plant Species

Matt MacDonald

~30 species used to date

Lasting Nutrient Storage

Matt MacDonald

harties.za.org

Lasting Nutrient Storage

Matt MacDonald

Open Water (Oxygen Exchange)

Matt MacDonald

How is the University of Washington involved with

floating wetlands?

Green Futures Lab

Urban Shorelines

Past Present Future

Matt MacDonald

Where might King County use floating wetlands?

•  Detention ponds and water quality treatment •  Urbanized wetlands •  Hardened shorelines •  Levies (trees no longer permitted)

Matt MacDonald

depts.washington.edu/wet/

Why do floating wetlands matter?

•  Provide wetland functions, structures and processes

•  Can be configured to existing aquatic environments

•  Scalable and cost effective

“The best way to predict your future is to create it.”

-Abraham Lincoln

Questions?

Mason Bowles Professional Wetland Scientist [email protected] Sally Abella Senior Engineer, Limnologist [email protected] Nancy Rottle Assoc. Professor, Director of Green Futures Lab [email protected] Matt MacDonald floating wetlands enthusiast and designer [email protected]

tinyurl.com/FloatingWetlandsSeattle (lots of links and other goodies!)

Matt MacDonald

Matt MacDonald

Overhanging Canopy

Matt MacDonald