The Frederick City Watershed: Forecasting Climate Change Impacts

Abstract

This report serves to assist The City of Frederick in making future planning decisions about the Frederick City Watershed, a 7,000 acre, forested property just west of the city. Specifically, this report will address the question of how the Frederick City Watershed will be impacted by anticipated shifts in precipitation and extreme weather events due to climate change. To assess the potential impacts that climate change may have on the Frederick City Watershed, climate models were applied to the watershed area and a forecast of several climate variables such as temperature, precipitation, snowfall, runoff, evapotranspiration and wind speed were evaluated. The data used for forecasting climate change impacts was taken from the Downscaled CMIP3 and CMIP5 Climate and Hydrology Projections website (Maurer et al, 2007; Reclamation, 2014). The datasets aim to provide a set of high resolution, bias-corrected climate change projections. These can be used to evaluate climate change impacts on processes that are sensitive to finer-scale climate gradients and the effects of local topography on climate conditions. Two scenarios were projected: the RCP 4.5 business-as-usual trajectory, and RCP 8.5 worst case emissions scenario. In addition to the climate modeling, an extensive literature review of potential climate factors on ecosystem services was conducted. Under both modeling scenarios, temperatures are predicted to increase significantly across seasons and over the course of the century. Precipitation will remain fairly constant, but the greatest increase will occur in winter and spring; more of the precipitation will fall as rain rather than as snow. Runoff and soil moisture is expected to increase slightly during the winter and spring for both emissions scenarios, while evapotranspiration is expected to see significant increases in the spring, summer and fall. The models project no change in wind speed. Overall, the results demonstrate a significant increase in temperature, which would seasonally affect the duration and type of precipitation, evapotranspiration, soil moisture and runoff. Changes in these variables translate to specific implications for the Frederick City Watershed ecosystem, including decreased water quality due to increased storm water runoff, an increased spread of invasive plant species, and a rise in plant diseases. In order to effectively manage The City of Frederick’s drinking water supply, the city should prepare for anticipated changes in climatic variables. Given the model projections, The City of Frederick should consider the following management techniques for the City of Frederick Watershed: commit to creating a Frederick City Watershed water balance model; incorporate regional water management and storage strategies; implement storm water management techniques; monitor water quality; and prepare for increased pest outbreaks. These suggested management measures will strengthen the city’s resilience and ensure that The City of Frederick will be able to continually provide adequate supplies under both current and potential future climate change conditions.

Notes

Final project for CONS670 Conservation Biology (Fall 2014). Sustainable Development and Conservation Biology, University of Maryland, College Park.

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