Designing Sustainable Farming Methods: Clam Gardens

The industrial revolution’s farm harvesting technology improvements have seen the rise of large scale industrial farming in the past century. Any individual who has driven on Interstate 5 in California, or flown over the “fly-over states”of the Midwest have noticed these vast stretches of land farmed with resource intensive, mono-culture cultivation practices. Farming accounts for 70% of the world’s use of potable water (World Wildlife 2022). The heavy water use, single crop planting, and Genetically Modified Organism (GMO) plants are an unsustainable form of cultivating food. We are starting to see the biological and chemical effects of this method through the destruction of soil structure and chemical pollution to both humans and wildlife (Farm Management 2022). Increased knowledge of water runoff, soil design, and holistic design strategies for a more integrated agricultural management by Landscape Architects would be beneficial to creating more sustainable food production methods (Peterson 2016).

Agriculture is unsustainable because the methods do not take advantage of existing ecosystems, so the soil is dependent upon human intervention to provide fertilizer and pesticides (Friedemann, 2017). In a more integrated management system, the elements of the cycle can benefit each other on a more consistent basis.  The rise of aquaculture management practices have gained considerable attention with the NY project of reintroducing bivalves to the Hudson bay. An important side effect of this reintroduction was the bivalves' ability to clean the water as they filter feed, thus increasing suitability of the environment to other plants and animals. Reintroducing bivalves provided habitats for additional organisms and decreased land degradation. (NOAA Fisheries, 2020)

Aquaculture methods have been gaining increased attention in the Pacific Northwest due to climate change’s noticeable impact on clam species. Rising sea temperatures has decreased the amount of algae that clams depend on and has made the ocean more acidic, causing a population decline. Clams that are good for human consumption, specifically butter clams or little neck clams, have a very specific depth (.5-2 m at intertidal height)  that provide optimal growing conditions. Fewer clams are readily dug out of the ground every year where once a bucket was filled within the first few minutes (O’Neil 2019). Finding the same amount of clams now takes easily an hour or more. Commercial clam farming is not a viable solution to solving the decreasing clam population, as it also creates a mono-culture growing problem. Tide land cleared for these purposes does not support the surrounding ecosystem, and is incredibly labor intensive. Anthropologists have looked to historic landscape aquacultural methods to solve a growing problem of clam species dying out.

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Remains of organized rock walls can be viewed all along the coasts of British Columbia. Site observations and oral history accounts from local tribal elders reveal that Native American tribes designed and built sea gardens that would increase the amount of surface area at a certain elevation to encourage clams to grow. These gardens were built by utilizing rocks within the tidal beds and creating structures that were visible only at the low tide mark. The sediment built up against these walls and created a gentle slope for the beach that was the ideal tidal depth for clams to grow in, additionally, it moderated the water temperature by creating cooler temperatures in the summer, and warmer temperatures in the winter (Moliere 2022). Continued maintenance of these rock gardens included removing rocks and unearthing the breathing holes of the clams by removing excess seaweed (clam garden.com) (Selkirk 2022) In the last two decades, a coalition of researchers, First Nations, and National Parks have re-introduced this practice to key areas along the Pacific Northwest Islands. In a study of shellfish production by Groesbeck et. al, it was found that the clam gardens increased productivity by 150-300% as well as increased the size of butterclams, cockles, littleneck, and manila clams in comparison to unwalled beaches (Clam Garden Network) (Groesbeck et. al 2014). Biologists have observed how the human made rock wall re-introduces a reef to the area, supporting other forms of wildlife such as octopuses, sea cucumbers, and whelks who thrive in protected areas. This “wild” form of aquaculture is in harmony with the land and allows the First Nations people to only take what they need, and leave the rest to nature.

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From a landscape design perspective, one of the most critical but intangible aspects of this practice is the stewardship mentality that is a key aspect of First Nation culture. The collection of these clams carries economic, social, and cultural importance to the first nation peoples as it is a place to gather, show gratitude to the environment and ancestors, and a source of fresh food. The community and cultural events that surround digging clams extend not just to the act itself but through plays, songs, and artwork that celebrate a gratitude towards the land to provide food (Clam Garden Network). This is a marked difference from the modern agricultural ideology, which is dependent upon creating as much yield as possible for both economic and psychological reasons within the food market. It demonstrates that in order to redesign sustainable methods, designers will need to account for paradigm shifts. Hopefully more landscape architects can subtly change society’s concept of food by shaping the world around us.

Native tribes enacted landscape design solutions that provided sustainable and an almost symbiotic relationship to the land. By creating water gardens that took advantage of natural systems, they created a steady food production system they could control. Through minute understandings of the land, remains of sea gardens with multiple other functions have been found, such as salmon traps, octopus houses, and many more that take advantage of the tides and knowledge of animal behaviors (Pacific Sea Garden Collective 2022).

By drawing from the intimate knowledge, previous practice of working the land, and working with communities, landscape architects are in a good position to facilitate future strategies to help combat climate change. Design strategies would improve biodiversity by providing solutions that take into account water drainage/ use and “cultural interpretations of the land” - both past and future - on a large scale (Peterson 2016). Integrating community values and action is critical to the continued success of more resilient land management practices.

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