Assessments and Forecasts of the Ecological Health of the Upper Mississippi River System Floodplain Reaches

Status Gauges For a grading system to be of the greatest value to the river community, it must be brief, understandable, objective, and relevant. The system of gauges used in Table 16-1 visually describes the ecological health of the four floodplain reaches of the UMRS. The notations in Figure 16-1 are used to evaluate each river reach. In addition to pointing to current status, the gauges (Figure 16-1; Table 16-1) indicate whether the conditions are believed to be stable, improving, or declining. The term “stable,” as it applies to floodplain river ecological health, refers to conditions assessed over multiple years (optimally 5–10 years). It disregards seasonal or year-to-year changes that are associated strictly with short-term hydrologic regimes. The criteria of recovery from disturbance and sustainability are by nature intimately tied to changes defined over relatively long time intervals. Our knowledge of the ecology of Upper Mississippi River System (UMRS) floodplain reaches is extensive, as demonstrated in previous chapters. That knowledge, however, is rarely complete for a selected habitat, species, or biological process. Although many historical data gaps cannot be filled, the Long Term Resource Monitoring Program (LTRMP) has made major strides in initiating and maintaining the consistent standard observations necessary to assess important ecological trends. A well-designed monitoring system is the first step toward being able to improve and sustain the ecological quality of the UMRS floodplain reaches. The next step is to assist the river community in the creation of an objective, functional grading system to measure the acceptability of ecological conditions within each reach and clarify what management actions are the most urgent. In this chapter we compare the river health criteria described in Chapter 2 with the UMRS observations presented in Chapters 4 through 15. This comparison is an initial assessment step within an evolving adaptive river management strategy