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Delridge Wetland and Stewardship Project

The Delridge Wetland, located on 23rd Ave SW and SW Findlay St, is a project spearheaded by DNDA to protect, restore, preserve and expand the existing wetland to improve water quality in Longfellow Creek, meanwhile developing the space as a public park for all to enjoy. Beside wetland restoration, other plans for the park include the creation of an urban garden, community orchard, as well as developing the space as an outdoor classroom for local students and the community to learn hands-on environmental science and wetland stewardship.

Updated wetlands drawing plan

Designing the Delridge Wetland Park

Kicking off the design process, our partners at Pomegranate Center began developing the first draft of their master plan in May 2017. This process relied heavily on input from the project’s partners and included two day-long design forums as well as a third forum with local educators. Partners of the Delridge Wetlands and Stewardship Project include Seattle Green Spaces Coalition, Seattle City LightSeattle Public UtilitiesLouisa Boren STEM K-8Duwamish Alive CoalitionNational Park ServiceTilth AllianceCity Fruit, and Solid Ground.

Strengthening DNDA’s relationship with local educators, Pomegranate Center created a curriculum that would enable students at Louisa Boren STEM K-8 to contribute to the Wetlands design plan through science experiments, art projects and presenting their projects at school. A class of both fifth and third graders studied wetland water function by testing water quality and different substrates, while two other third grade classes focused on studying plants, animal habitats and human activity. These topics included science experiments such as using a homemade clinometer to measure tree heights, testing soil quality, studying plant biofiltration capacity by observing water uptake in celery stalks, and researching specific needs for local wildlife habitats.


After conducting their experiments, students continued to create their personal vision of the Delridge Wetlands through clay models. Students were given a map of what the Delridge Wetlands currently looks like and used clay to redesign the space using their new knowledge of water features, plants and habitats.


Wrapping up the experiments and activities, students were able to share their findings at Louisa Boren K-8’s school-wide Project Based Learning Night. Meanwhile, DNDA was also tabling at the event to showcase the students’ findings, provide information about the Delridge Wetlands and invite families to the community-wide design open house that took place at DNDA’s Youngstown Cultural Arts Center on June 15, 2017. This open house provided Delridge Wetlands partners with valuable community feedback in response to Pomegranate Center’s initial designs that consisted of 3 alternative plans. This essential community feedback, combined with input from local students and educators, will allow our design team to create a master plan for the Delridge Wetlands that encompasses all of our collective visions.

We are pleased to have so many community members already planning to contribute their time and energy volunteering to help clean up the site, to participate in sheet mulching the site and to participate in removal of invasive species on the perimeter of the proposed park site.  To connect to the project and to volunteer for work parties please contact Caroline Borsenik, DNDA’s Environmental Programs Director.

Construction and Restoration Progress


The large cottonwood trees in the middle of the wetland were removed to clear space for native wetland plants. Cottonwoods do not occur naturally in wetland areas, so in order to fully restore our wetland, we cut down the trees and girdled the stumps to prevent regrowth. Volunteers helped us remove invasive blackberry and Canadian thistle, and we installed several native evergreens.




Over 7,000 square feet of invasive plant removal and mulching was done in the wetland. 8 Western red cedar trees, 33 native shrubs, 120 native ferns and 2,010 native emergent plants were planted throughout the year. To improve the hydrology of the wetland, a watering system was implemented over the summer and coir logs were placed at the inlet and outlet of the wetland to help trap and filter out debris in the water passing through.






Volunteers and students planted 180 emergent and 70 groundcover plants, mulched 1,525 square feet of planting space, and cleared 4,756 square feet of invasive species such as Himalayan blackberry, reed canary grass and bindweed. Our partner classrooms from Louisa Boren STEM K-8 spent 994 hours in the classroom and 884 hours in the wetland creating planting plans, building experimental wetland planters, making mosaic signs, installing plants, and studying topics such as wetland science, wetland soils and chemical monitoring. 300 people attended our six Wetland Workshops, 175 of which were students. The workshops included two block parties, a Wetland Birds & Habitat seminar, two wetland health monitoring workshops and an environmental career day for students.

The chain-link fence surrounding the entry and the inlet of the wetland park was removed to clear up space for us to remove the old, inefficient watering system. We are currently installing a storage shed and a trellis in its place.



Community Building

Restoring the wetland isn’t just about making our local environment healthier by reducing flooding, improving water quality and enhancing wildlife habitat. In addition to engaging local schools and getting youth involved with environmental stewardship and hands-on science, a key aspect of our mission for the Delridge Wetland Park is to create a welcoming place for you to connect with your community. By installing edible native plants and creating a community food garden, we will increase access to healthy food in the neighborhood. The gathering space will also be ideal for socializing with friends and neighbors, or for simply enjoying the beauty of nature.

Our weekly wetland restoration work parties serve to bring people together under a common cause. Working together to make our neighborhood a healthier place to live can help strengthen our community ties and relationships.

Creating an Outdoor Classroom

We are creating a strong connection with our local area schools. Our work with schools focuses on classroom visits to the site. Staff of DNDA and our contractors have gone into the classrooms and presented information on the project, the role of wetlands in the watershed and how water moves throughout the region. Outdoor Classroom Design has worked directly with teachers to develop Lesson Plans, developed activities for the site visits to expand upon classroom instruction, and together Outdoor Classroom Design and DNDA have supported specific projects with the students that have been unveiled at Project Based Learning Night at STEM.

Our Louisa Boren STEM students participate in and monitor different aspects of the Delridge Wetland Park’s ecological restoration. Each grade has a different curricular goal illustrating wetland function and recovery.

  • Our 3rd graders explore what conditions make a wetland and how plants and water interact to make a unique ecosystem.
  • Our 4th graders explore erosion and storm water dynamics on a watershed scale as they are relevant to salmon and the health of our wetland.
  • Our 5th graders monitor and interpret the progress of ecosystem restoration at the wetland, share this information with other students, community and future classes.

Examples of student work:

3rd Grade Infiltration Experiment
3rd Grade Infiltration Experiment
Topographic Model - Project Based Learning Night 2018
Topographic Model - Project Based Learning Night 2018
5th Grade Water Quality Monitoring
5th Grade Water Quality Monitoring
4th Grade Planting
4th Grade Planting
4th Grade Wetland Ethnobotany Activity
4th Grade Wetland Ethnobotany Activity
3rd Grade Art Activity
3rd Grade Art Activity

Our 5th graders at Louisa Boren STEM have been a part of rebuilding the Delridge Wetland Park for the past three years. Their research projects can be found here.

Follow the Delridge Wetland Park on Instagram to see how local students are using the Delridge Wetland Park as an outdoor classroom for hands-on environmental science lessons.

Community Health Profile

Developed in partnership with the National Park Service, this community health profile examines existing health indicators and needs of residents living in the Delridge corridor, a planning zone along Delridge Way SW. It considers both community health and the built environment. It contains information about the potential impacts of the future Delridge Wetland Park on the health of Delridge residents and makes recommendations for its planning and design, programming, and monitoring and evaluation.

This document is a result of research on existing plans related to health in Delridge, as well as input from a team of local community leaders and organizations that have come together as thinking partners to make decisions on the wetland park. A big thank you to all who contributed their insights to this community health profile!

Wetlands Project Partners

Wetlands Project Funders