UERLA Report: Understanding the Effects of Tree Removal in Soapstone Valley Using i-Tree Software

Oliver, Lily

i-Tree Hydro modelling is used to predict the effects of tree removal, one element of a planned sewer rehabilitation project, on the total flow, pervious runoff, and total suspended solids in the Soapstone Valley satellite park of Rock Creek Park and in the Soapstone Valley watershed. These factors are important to understand given the specific concerns of flooding and erosion in Rock Creek Park. i-Tree Canopy is used to calculate the land cover percentages for the i-Tree Hydro cover classes, while literature searches, a site visit to Soapstone Valley, and consultation with i-Tree experts also informed model inputs. The different land cover cases modelled include the current land cover prior to tree removal, predicted land cover after tree removal, and a possible revegetation scenario. Each of these cases are modelled during 3 representative years (average precipitation, a wet year, and a dry year) from the last 10 years. Additionally, a short-term, high intensity storm event and a long duration, low intensity storm event are modelled to understand the impacts of these two extremes. It appears that this project will have very little effect on both the Soapstone Valley watershed and Soapstone Valley Park scales. Further alterations to the inputs, including design, artificially created to have a specific intensity, duration, and frequency, storm events and consideration of erosion and sediment control measures, would be useful directions for future research.