HNA Summary Report
Habitat Needs

The EMP Habitat Needs Assessment defines habitat "needs" as the difference between "existing conditions" and "desired future conditions." To calculate "need," a system-wide accounting of existing, predicted, and desired habitat conditions was thus developed. This effort revealed some clear differences among river reaches. For example, land cover analysis clearly documents an abundance of certain valuable habitat types in northern river reaches, versus a scarcity of those habitats in southern river reaches. The differences are largely related to the amount and distribution of public land, the degree of floodplain development, the geomorphic form of the river, and effects of impoundment for navigation. In addition, analysis of geomorphic changes indicates that some changes (such as loss of backwaters) are systemic, while other changes (such as island dissection) are more localized. Understanding these differences can help identify what types of restoration efforts are most appropriate for each river reach.

Though differences among reaches are significant, resource managers have generally concluded that habitats are currently degraded and expected to get worse. The factors responsible for degradation (e.g., sedimentation, impoundment, channelization, levees, etc.) also suggest the most promising avenues for ecological restoration.

Quantitative assessments of need are obviously difficult and thus do not provide precise estimates of change or need. Nor do the gross quantitative estimates suggest precisely where on the river changes are needed. Nevertheless this initial assessment, based on input from resource managers and scientists, identifies which types of geomorphic areas need emphasis in various river reaches and pools to achieve the broad restoration objectives.