Dynamic Coupling of the Water Cycle and Patterns of Urban Growth

The objective of this project is to link an urban growth model (SLEUTH) with a fully-coupled, physically-based three-dimensional hydrologic model (PARFLOW-CLM) to evaluate the effects of growth on water availability and limits to water supply using the Baltimore metropolitan region as a case study. The urban growth modeling will consist of a rigorous and fully validated implementation of the SLEUTH model coupled with a spatial statistical model of urban suitability and demographic data. In addition to providing a platform where both landscape characteristics and socio-economic variables can be integrated, this model will provide the opportunity to test and quantify the influence of each of these variables in either attracting or resisting development. Because the model will have a better representation of the landscape in terms of where development is more or less likely to occur, the models performance will be improved. Implementation of the hydrologic component of the project will include intensive field studies on a single highly urbanized watershed, which is the primary study watershed of the Baltimore Ecosystem Study LTER research site. Combining a physically-based regional hydrologic model with an urban growth model will allow an assessment of the coupled feedbacks between growth projections (and the socio-economic variables that affect growth) and surface and subsurface water resources. Changes in stream baseflow and groundwater availability may in turn influence regulatory decisions on development permits in exurban areas. This project will link smaller-scale, process-based studies to a larger scale regional understanding of how the water cycle operates. This project will also advance several long-term goals for urban land cover modeling. Most significantly will be an opportunity to develop the links between urbanization and hydrologic systems in a spatially explicit context. The importance of water resource management to serve the public interest is a topic of growing importance globally because of stresses induced by patterns of growth, but the tools and data currently available to support decision-making are inadequate. This research will help to close that gap. This effort is also of interest to the Chesapeake Bay program, in its work to address questions about critical thresholds and sustainability.Interaction with state and local agency personnel will be carried out in order to incorporate their questions and policy concerns into modeling scenarios and to discuss the implications of the findings from this project.