Urban Stream Assessment Procedure (USAP): A Framework for Assessing Stream Health in the Urban Environment

Various multi-scale hierarchical river health approaches and assessments have been developed and implemented with a variety of scientific and management purposes. Although many existing biological and geomorphological assessments offer insights into stream function, none were developed for or exclusively capture the totality of function of streams in the urban environment. Quantitative aspects of existing screening tools are limited in urban streams due to the unique combination of hydrogeomorphic and anthropogenic factors in the urban environment. Analyzing the physical, biological, and social drivers within the concept of the urban stream syndrome coupled with recent advances in stream assessments connects the health of urban streams with past, present, and future impacts. The Urban Stream Assessment Procedure (USAP) provides an innovative framework and conceptual model to comprehensively assess stream functions in the urban environment and quantify their health at multiple scales. The framework focuses on integrating the objectives of ecological quality, geomorphic stability, hydrologic continuity, and social/community uses of streams in the urban environment. The specific aim is to identify the highest function and lowest maintenance "version" of an urban stream that is achievable given the context - varying hydrologic regimes, geomorphic conditions, ecological diversity, social contexts, and community goals. The USAP framework builds on existing and recent advances in hydrological, geomorphological, and ecological assessments. It is designed to classify urban stream reaches and corridors according to their hydrological, geomorphological, vegetation characteristics using site specific data and to support identification of those stream reaches that might be candidates for rehabilitation. Employing a multi-scale framework yields greater success in assessing stream function, diagnosing watershed-wide drivers, and implementing specific strategies to enhance streams in the urban environment. Furthermore, the USAP framework assists water resources managers in assessing and managing health specific to urban streams through applicable spatial and relevant parameters and metrics.