'IKE WAI + SUMIDA FARM PARTNERSHIP

By Emi Suzuki

Sumida Farm has always understood the secret to our world class watercress is the perfect combination of fresh, clean spring water and abundant sun that shines over our little 10 acres of leased Kamehameha Schools land. One of the primary reasons first generation Sumida Farm managers, Makiyo and Moriichi Sumida, chose to grow watercress on this land was the fact that it could be grown year round due to these unique conditions, nourishing the islands consistently across the year. 

Over the last decade, we began to notice a sharp decline in watercress production beginning in July, which marked the start of Hawai’i’s hotter, more humid, and longer summer season. We started to plan for what has now become a reliable enemy to the farm--the “summer decline” brought on by long days with relentless heat and humidity and limited trade winds to cool the islands at night. A phenomenon known as “King Tides” that includes exceptionally high tides and is exacerbated by global warming has made the water on the makai side of the farm slightly salty, which is not good for our fresh water watercress varietal. 

Through all of these challenges, we were fortunate to be selected as a case study for the ‘Ike Wai Project, in partnership with UH, which seeks to better understand through cross-discipline research how the effects of urbanization and climate change are impacting local agriculture and the islands' fresh water sources, and provide data to support future decision making.

Some key findings of the study were the data backed validation that the Kalauao Springs that feed our farm are clean and pure, with no detectable traces of contaminates typically seen in water runoff in urban areas. This research indicates “the Kalauao Spring’s source has been geologically isolated from human pollutants.” They found our watercress provides vital bioreactive nitrogen removal in the midst of a concrete desert, helping to provide important water quality protection for the surrounding community. Through community and family interviews and extensive research looking at mo’olelos from the Hawaiian Language Newspaper Repository, the researchers concluded there is social and cultural value to the farm, as a peaceful green landscape that connects the community with a sense of place and heritage. 

The research also provided evidence that rising sea levels are causing our water to become saltier and through a 25 year retrospective analysis of crop data, concluded that sustained heat leads to sharp declines in watercress production. As the effects of global warming continue to escalate, our farm will have to adapt and evolve to survive unprecedented environmental growing conditions. 

Our Sumida Farm family thanks the ‘Ike Wai team for allowing us to participate in this vital research. Their work has helped us plan for the future to ensure we continue to nourish the islands for future generations. Join us in helping to protect our islands’ natural resources by learning more about this important research and doing your part to help conserve and preserve our planet's limited fresh water resources.