ERE graduate student Emily Stephan has received a Research Assistantship Program award from the Mianus River Gorge Preserve (MRGP) to study the influence of land use and management on nutrient cycling in watersheds. Her research will focus on nutrient cycling in the Mianus River watershed, which has an area of approximately 42 square miles and spans the towns of Bedford, North Castle and Pound Ridge in New York, as well as Greenwich and Stamford in Connecticut. Emily will be doing water chemistry analysis, specifically focusing on nitrogen and phosphorus species, at various points within the Mianus River watershed, choosing locations which drain areas of varying land use.


Figure 1 – Map of 2006 land cover for the Mianus River watershed

Emily’s sampling efforts will help to inform the development of a new nutrient routine for nitrogen and phosphorus which she will develop for i-Tree Hydro, a tool developed by the teams of Dr. Ted Endreny and Dr. Chuck Kroll at SUNY ESF in collaboration with the USDA Forest Service. The current water quality estimates of i-Tree Hydro are based on proven event mean concentration algorithms advocated by the US Environmental Protection Agency (EPA) and used in many watershed models, including the US EPA Stormwater Management Model (SWMM). While the event mean concentration algorithms are based on empirical data and are able to predict stormwater nitrogen loads in i-Tree, i-Tree does not have the next-step algorithm that simulates how vegetation can intercept and filter nitrogen from the stormwater. Through Emily’s research, we hope to be able to model the effects of such efforts as stormwater management structures as well as the effect of increasing tree cover and reducing connected impervious area.


Figure 2 – A forested piece of the Mianus River, near the Mianus River Gorge Preserve office in Bedford, NY

Recent research suggests that human influence may well be the driving factor behind urban biogeochemical cycling. Therefore, there have been several studies examining the effects of human decision on nutrient loading in urban watersheds. Carey et al. 2013 suggest that it will be important to monitor turfgrass, pet waste, and septic systems as potential significant sources of nutrient loading in urbanizing/urbanized watersheds. Emily hopes to utilize the connections between the Mianus River watershed communities and the Mianus River Gorge Preserve to develop surveys that will lead to a spatial distribution of where these sources of nutrients lie within the watershed, and how their harmful effects can be mitigated with land management decisions.


Figure 3 – Emily discusses the goals of her project with MRGP Executive Director Rod Christie, MRGP Director of Research & Land Management Chris Nagy, and MRGP undergraduate interns Chris and Alex

Stay tuned for more updates regarding Emily’s work down in the Mianus River watershed!