Comprehensive evaluations that consider all the important aspects of stream health are the foundation for understanding existing ecological conditions and the environmental impacts of proposed actions. A wide variety of assessment methodologies appear in the scientific literature, regulatory processes, and in common practice. Some approaches focus on aquatic species habitat, while others focus on water quality, riparian function, or geomorphological processes. While well-established methods are available to practitioners engaged in assessments of specific aspects of river and stream conditions, fewer structures exist for completing and communicating more holistic characterizations best suited for informing management actions.
Multifaceted approaches that integrate a suite of evaluation methodologies, while requiring more effort, are more adept at predicting secondary impacts and identifying key limiting factors that may not be recognized by assessment approaches that rely on narrowly focused methods. For example, some environmental flow assessments focus on trout habitat needs by employing simple models like R2Cross. While useful in their own right, management recommendations based solely on these assessments may neglect important connections between peak flows, sediment dynamics, water quality and other conditions that may limit habitat quality and aquatic life health in a more profound manner than low flows. Practitioners are more likely to identify such synergistic impacts and/or key limiting factors when assessment methods consider conditions across an array of river sub-disciplines. Integrated and comprehensive evaluations are better suited to couching ecological assessment results in terms that encourage a shared understanding of river conditions and directly inform the development and prioritization of management actions that protect or improve those conditions.
A comprehensive evaluation of stream health is the basis for informed management decisions in which stakeholders can understand both existing ecological conditions and the environmental ramifications of proposed actions. The Colorado River Health Assessment Framework (CoRHAF) is a high-level, scale-independent organization framework that accommodates diverse assessment methodologies, allowing flexibility in planning and data-gathering exercises based on specific planning objectives, data limitations, organizational capacity, and available expertise. By defining a common language for organizing and reporting river health assessment efforts, the CoRHAF makes it possible to compare conditions among interrelated drivers of ecological condition, between adjacent stream segments in a watershed, and at a given location across time.
Aside from providing a level of standardization to river health assessments in Colorado and a big head start on developing and implementing one for your river, this guidance aims to simplify the development of Requests for Proposals (RFPs) and Scopes of Work (SOWs) for future stream health assessment and planning efforts. It should also prompt practitioners to design and implement more comprehensive and practicable assessments of stream and river health. The the many examples of health assessments available on the Colorado SMP webpage provide case-studies that demonstrate how to carry out an assessment of river health.
This User Guide is intended for the practitioner, technical team, or organization charged with implementation of a CoRHAF assessment. The guide is presented in three sections that correspond the the sequence of planning and assessment activities expected in most locations. Supplementary material supporting implementation is provided on the Resources page.
Section 1: Pre-Assessment Activities
This section outlines the numerous steps necessary for ensuring project success. This includes strategies and guidance for securing funding, supporting your assessment with technical expertise, and appropriately scoping your assessment activities within the context of a larger planning effort.
Section 2: The CoRHAF Protocol
This section begins by diving into the core structure of CoRHAF and opportunities for customization, going on to explain the development, adoption or modification of Grading Guidelines that describe the conditions. Guidance on selecting methods used to assess functional conditions is presented, along with advice for assessment implementation. Finally, this section discusses strategies for aggregating river health grades to aid in results communication.
Section 3: Post-Assessment Activities
This section discusses strategies for communicating results results with diverse audiences, integrating river health assessment findings into broader strategic planning documents, and preserving river health assessment data and records.
