BioCatchment Design Challenge
Better water. Better fit. Beautiful design.
2026 - 2027 SCHOOL YEAR
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The Problem(s)
The Problem(s)
Rain barrels are a cheap and effective way to catch rainwater that can be used anytime to water plants. BUT! Rain barrels are unsuitable for many urban residential settings for at least 3 reasons (listed below).
1. Too Little Space
1. Too Little Space
A standard 55-gallon barrel has a 2' x 2' footprint that would obstruct walkways - that's neither safe nor convenient!
2. Poor Water Quality
2. Poor Water Quality
Rooftops can be pretty dirty- asphalt roofs can release Polycyclic Aromatic Hydrocarbons; heavy metals like zinc, copper, lead, and iron; and other harmful pollutants. Rain collected from roof runoff should only be used to water non-edible plants. But what if a catchment system could naturally filter that water to make it safer?
3. Aesthetics
3. Aesthetics
A repurposed barrel to catch and store rain is a wonderful way to keep its plastic out of the landfill and environment, but many people don't want to display plastic barrels on their property.
Could there be a way to design something that:
1. Fits in tight spaces
2. Improves the water quality
3. Looks beautiful
The Challenge: Design & Build a Better System
The Challenge: Design & Build a Better System
The ultimate goal of this challenge is for participants to put forth their best fully built biofiltration catchment system that can be perfected by professional engineers to scale and install at homes across the watershed.
Draw Inspiration from Existing Designs
At Right: The wooden planter boxes are "Storm GUARDens" designed and built by some very inventive people in Wisconsin! Slimline form, natural filtration, and beautiful aesthetics make this design a great example!
Below: A cross section of a Grattix box designed to naturally filter stormwater runoff. Images are from the Lower Columbia Estuary Partnership. Do any of the images inspire the designer in you?
If this design challenge sounds like something you and your class, friends, or group is interested in, please fill out the form below and be sure to read the details on the Design Parameters webpage.
Note: funding as of 10/13/2025 is not available though we are seeking sponsors to support materials procurement, workshops, and prizes. Rainwater@hawaiigreengrowth.org
Resources
Whether you're looking to learn about the basics of how rain catchment works, building a rain barrel, or designing a nature-based passive water filter, we have a collection of resources to help you get started here.
FAQs
What format should my submission be in? Submissions should be a complete, fully built rain catchment system with biofiltration properties.
When are submissions due? Submissions are due by April 22, 2026 for testing and demonstration. Winners will be chosen by the end of the spring 2026 semester.
Do I need a supervisor to assist me with the project? Yes, each participating team must have a sponsor (e.g., a teacher or parent volunteer) to help them safely use equipment when assembling projects.
Is funding available for materials? We are currently seeking funding to support participants' budgets.
Who will judge my system? Experts from engineering, water quality, landscape design, and manufacturing will score projects based on the rubric.
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