Abstract

Climate, land use and land cover changes can have a substantial impact on the hydrologic cycle. Additionally, it is predicted that climate change will bring a rise in temperatures leading to periods of drought and increasing the risk of wildfire incidence.There is a need to evaluate how these disturbances will alter downstream water quality and quantity with respect to biodiversity. In particular, wildland-urban interfaces (WUI) and urban watersheds may be especially vulnerable to these pressures, which can lead to disturbances of ecological habitats, concerns about public health, and disportionate impacts to marginalized communities. This research will focus on landscape changes within southern California (United States), and more particularly on the Arroyo Seco watershed within the Angeles National Forest. The goal of this research is to better understand the anthropogenic effects on wildlands and biodiversity utilizing a physically-based hydrologic model, the Loading Simulation Program C++ (LSPC). We will establish a suite of streamflow metrics and water quality parameters for a baseline or pre-disturbance condition from which we will assess changes to the hydrologic cycle. The alterations in streamflow metrics that characterize aquatic habitat such as depth of water or temperature, will be used to evaluate ecological sensitivity. Using spatio-temporal data, we will simulate various scenarios due to fluctuations in climate and changes in land cover and soil type, allowing for comparative studies of disturbances caused by natural and anthropogenic sources. Hydro-ecological response relationships can be developed and studied to understand the underlying interactions between communities, landscape, water quality, soil variations and ecosystems at a regional scale. This research is part of a pilot study that is seeking to create a comprehensive approach to environmental watershed management for planners and land managers. This framework can be used to assess riverine conditions and provide guidance for planning, rehabilitating and preserving streams and rivers while leading to the protection of biodiversity within the region. Additionally this framework will provide a quantitative risk assessment that can be used to identify priority areas for conservation and rehabilitation.