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Environmental Analysis

Research Presentation Video

Click to watch Nathaniel Yale '14 discuss his research project.

Filtration of heavy metals in stormwater by bioswales in Portland, OR

Na'ama Schweitzer (2013); Additional Collaborator(s): Alan Yeakley*; Mentor(s): Robert Gaines
*Portland State University

Abstract: Bioswales are a sustainable solution for urban stormwater management, intended to capture stormwater accumulating on roads and infiltrate it back into the soil, thus preventing stream pollution and recharging groundwater. Understanding the effectiveness of bioswales in improving water quality is essential with respect to implications for groundwater recharge and the sustainability of the facilities over time. This project used simulated storms relying on the accumulation of pollutants on streets in dry weather periods to test the heavy metal retention efficiency of some of these facilities. Five two-hour tests were conducted at three different sites; samples were taken every nine minutes from the inlet of the facility and an outlet of a perforated pipe running through the bottom of the bioswale. Water flowed from a hydrant down approximately 200 ft of the curb, with flow rates modeled on a hydrograph typical for storms in the area. Instantaneous concentrations and composite loads of Cd, Cr, Cu, Ni, Pb, and Zn were compared between the inlet and outlet of each site, and retention and centroid lag times were plotted over time for each simulated event. Preliminary data analysis suggests a significant drop in concentration between the initial inlet sample and the initial outlet sample, indicating high retention efficiency of the facilities, and implying effective reduction of heavy metal loading in street runoff.
Funding Provided by: Schulz Fund for Environmental Studies; ULTRA grant; Pomona College Environmental Analysis Program

Economic and Carbon Sequestration Potential of Pyrolysis Biochar Systems

Ryan Higgins (2014); Mentor(s): Richard Hazlett

Abstract: Destructive agriculture and irresponsible use of fossil fuels have caused an excess of atmospheric carbon paired with a lack of soil carbon, threatening both climate stability and food security at once. The use of biomass to create sustainable energy and healthier soils through Pyrolysis Biochar Systems could prove integral to resolving this issue. Pyrolysis is thermal decomposition of biomass resulting in the creation of charcoal, which is known through scientific experimentation and ancient cultural knowledge to have agricultural value, along with the byproducts of syngas and bio-oil, both valuable sources of renewable energy. Biochar is incredibly porous and its addition improves soil properties; greater surface area, higher cation exchange capacity, better air flow, greater water retention, and lower bulk density are all observed benefits. Biochar also has a “coral reef” effect in soils, encouraging the growth of beneficial microorganisms, and therefore vegetation as well (Bates, 2010). The development of a farming system which implements biochar would allow farmers to increase soil fertility and decrease fertilizer use, while simultaneously sequestering carbon in their land in the form of highly recalcitrant charcoal (Lehmann et al., 2009). This report is an assessment of the economic potential of Pyrolysis Biochar Systems, and of the significance of opportunities for the advancement of biochar technologies and systems with the help of carbon finance.
Funding Provided by: New Zealand Biochar Research Center, Massey University; Pomona College Environmental Analysis Program

Changing Agriculture and Food Security on the Big Island of Hawaii

Nathaniel W. Yale (2014); Mentor(s): Richard Hazlett

Abstract: After the downfall of plantation agriculture in the mid-20th century, Hawaii faces intense food insecurity combined with natural resource and biodiversity loss. Put in sharp relief especially by the isolation immediately following the 9/11 attacks, these problems are now beginning to get addressed through government action as well as budding local food movements. A look into the current food production culture on the Big Island of Hawaii has revealed that organic farms and the proliferation of farmer’s markets have an immense potential to help build Hawaii’s food security in a sustainable manner. While this is already occurring in certain cases, the state still has far to go in allocating land for polycultural production and weaning itself off of mainland imports. The movement to build food security in Hawaii can serve as a template for developing agricultural sustainability nationwide in coming decades, especially as pressures mount against synthetic fertilizer and pesticide production, and environmental impacts clearly become more serious.
Funding Provided by: Schulz Fund for Environmental Studies

Sustainable Fisheries: Considering Community-Based Management

Charlotte Dohrn (2013); Mentor(s): Nina Karnovsky

Abstract: The purpose of this research was to understand the sustainable management of U.S. fisheries on the west coast. I conducted 26 interviews in Alaska, Washington and Oregon of scientists, policy makers, commercial fishermen and stakeholders to determine how people interact with fisheries management and understand sustainability. I learned how stock assessments are made to establish annual catch limits for fishery management plans. I visited organizations within fishing communities including Port Orford, Oregon, and Sitka, Alaska and learned about the impacts of access and allocation policies. These communities have worked to maintain their local fishing industries under changing management while also supporting clean fishing practices and designating geographically specific conservation areas. I found that community-based fisheries management with federal and state oversight has a unique opportunity, through localized knowledge and regulation, to demonstrate a model of biological, social and economic sustainability for small-scale fisheries.
Funding Provided by: Schulz Fund for Environmental Studies

Research at Pomona