SI-4B (3/15/05 version)
Watershed-Based Options To Address Stream Integrity Impairment: Stream Reach Assessments
As noted in the overview, once a stream integrity problem is identified, steps 3 through 5 in recommending potential solutions are to evaluate the system at the stream reach scale. During this step of the evaluation process, available indicator data, collected during steps 1 and 2, is evaluated to determine the types of and locations where future disturbances to the stream channel and biology are likely to occur and predict the responses of both without intervention.
Several options to conduct this evaluation are outlined below.
- Designate Erosion Potential Areas
Once the stream classification and stage of evolution has been determined, it is possible to delineate areas projected to be eroded by stream meander migration within certain time frames (e.g. over 10 years, 20, 25 and 50 years. This option may be useful where channel recovery from unstable to stable is rapid, where lateral migration is prevalent, or simply where bank erosion is an issue. Examples of this approach are available at the following links:
- Sacramento River Conservation Area Forum Handbook;
- Riverine Erosion Hazard Areas Mapping Feasibility Study, Executive Summary;
- Riverine Erosion Hazard Areas Mapping Feasibility Study, Full Report.
- Long-term Stream Morphology Monitoring Sites
Establish sites where baseline measurements of key channel stability indicators are taken and channel conditions are monitored and re-surveyed over a period of years. Much of channel assessment is a "snap shot" of a dynamic process. Monitoring the morphology of a site allows assessment of channel process and change. Priority monitoring sites include high quality channels, impacted channels, and restored or naturalized channels. Methods to establish the monitoring site locations, baseline conditions, and changes over time may include establishing benchmarks, monumenting site for cross sectional measurements, and placing erosion pins and/or scour chains.
- Reference Sites
Become familiar with and quantify characteristics of "stable" channels with high biological/habitat quality. Use them as clues for determining the recovery/restoration potential of impacted channels. An online guide to conducting a reference reach analysis is available. An online spreadsheet and instructions (reference reach spreadsheet v4.0) is also available to organize data, once collected.
- Local Watershed Action Plans
Land uses, demographic trends, and local zoning and ordinances are addressed in local watershed action plans. This data may be useful in predicting how local land uses will affect stream integrity over time. More details on the status and content of local watershed action plans is available at the following links: