On November 1, 2017, graduate student Emily Kindervater successfully defended her Master’s thesis, titled “Phosphorus Retention in West Michigan Two-stage Agricultural Ditches”. Her thesis committee members included Dr. Alan Steinman, Dr. Mark Luttenton, and Dr. Rick Rediske of AWRI as well as Dr. Jennifer Tank from the University of Notre Dame.
Emily conducted her research in the Macatawa watershed of Holland and Zeeland, Michigan. The goal of her thesis was to better understand the phosphorus retention potential of two-stage ditches constructed for Project Clarity. Two-stage ditches have two floodplain benches excavated out of the traditional steep ditch banks and are intended to reduce erosion and nutrient export. She analyzed water quality, sediment and soil, vegetation, and algae in two separate two-stage systems to determine where phosphorus was bound and if the two-stage reaches were effectively reducing phosphorus export compared to reference reaches that remained in the traditional, trapezoidal shape. The majority of the phosphorus that was bound within the sediment and soil was within stable chemically bound fractions. The phosphorus bound in the two-stage was less likely to be released back into the water column compared to the traditional reference ditch reaches. There was no significant difference in phosphorus content of the vegetation and algae between the two-stage and reference reaches. One of the two-stage systems did not have significantly different water phosphorus concentrations, but did reduce turbidity. The other two-stage system had water flowing across the benches as well as the channel for most of the summer and had little vegetation on the benches which increased irradiance. This increased sediment-water contact area as well as increased algal mat growth and significantly reduced baseflow total phosphorus and the more bioavailable soluble reactive phosphorus, despite an increase in turbidity. Both systems are less than three years old and will become more stable with age. These results are preliminary and longitudinal studies should be conducted to understand how these systems change over time. Future two-stage research should focus on the sediment/soil within these systems as the largest and most stable sink for phosphorus.
Emily hopes to combine her research backgrounds in birds and aquatic systems to continue working in research, or to work with community members and students to get more people excited about science.