Sediment Risk Index (SRI) Stream Crossing Surveys - ARSN

The Alabama Rivers and Streams Netowrk (ARSN) Sediment Risk Index (SRI) was developed as a model for prioritizing stream crossings (SCs) in the Choctawhatchee watershed within southeast Alabama from 2006 to 2007. Over seventy-three variables were collected from SCs including information on waterway conditions, crossing structures, road approaches, and roadside soil erosion features that promote sediment delivery. These findings were summarized into a 12-metric index (the SRI), modeled after Karr’s Index of Biotic Integrity (IBI) for fish and other assemblages (Karr, 1981). The goal of condensing SC data into an index was to reduce the time and manpower investment of collecting data. Each metric of the SRI is standardized with scores 1 (most-impacted), 3 (moderately-impacted), or 5 (least-impacted) (Stewart et al., 2006). The scores for the 12 metrics are summed into a single SRI value ranging from 12 to 60, which is used for determining site rank and condition.