Garden Koi Pond with Bio-Filtration System - Introduction

This garden scale koi pond was built at The Occidental Arts and Ecology Center during our two-week Permaculture Design course in March of 2007. Unlike conventionally built ponds, this design utilizes a solar powered bio-filter to maintain water clarity.

This project was conceived of with several goals in mind:

• To create a beautiful water feature
• To enhance the soundscape with the sounds of water in motion
• To create a habitat feature and attract a diverse array of species
• To demonstrate a user-friendly design that utilizes solar photovoltaic panels to power a bio-filtration system that greatly enhances water quality.
• To provide a hands-on learning opportunity for students of our Permaculture Design course

This bio-filter emulates the ecological process that occurs between bodies of water and their associated wetlands. Inspired by Gaia and the work of John and Nancy Todd, Michael Ogden and Michael Littlewood, this design utilizes biological processes to ensure the optimal water quality level to support life.

The lava rock in this filter design plays an important role in maintaining the water quality of this system. It provides a large amount of surface area to volume upon which the nitrogen destroying organisms can grow. These organisms are denitrifying the fish wastes that would otherwise build up in toxic concentrations and make this pond uninhabitable to them. This system takes advantage of this by-product and turns “waste into food” for the nitrogen loving aquatic plants and other associated microorganisms. This eliminates the need to use a wide array of chemical inputs commonly associated with maintaining water quality in small garden ponds.

This design is unique in that the bio-filter is placed at the same elevation and immediately adjacent to the pond itself. This unifies the system visually and mechanically. It requires fewer materials overall to build and greatly increases the biological performance and overall aesthetic beauty.

The following pages describe the design and construction process in detail.  If you like what you read here, please consider making a donation to the WATER Institute.