ABSTRACT
Urbanization reduces the cumulative volume of water storage provided by soils and vegetation, increases the fraction of rainfall that becomes surface runoff during storms, creates structures to hasten the movement of runoff to streams, reduces evaporation, and increases watershed yield. Protecting the hydrology and water quality of streams in newly urbanizing basins requires comprehensive implementation of structural and nonstructural mitigation including but not limited to retention of natural vegetation, minimization of impervious surfaces, low impact site design, rain gardens, detention and infiltration facilities, and water quality treatment. The maximum possible extent of urbanization that can be accommodated while protecting local streams is uncertain.
