About Software

Software supports the Mesohabitat Simulation approach (MesoHABSIM); a set of tools addressing the assessment needs for watershed-based management of running waters (Parasiewicz 2008). This physical habitat simulation model describes the utility of instream habitat conditions for aquatic fauna, allowing the user to simulate change in habitat quality and quantity in response to alterations of flows or river morphology.

SIM-Stream Software manages two key elements of the model: physical data and biological data. The physical instream habitat data stem from field mapping surveys, which are entered as polygons and point data into a geographic information system. The polygons of mesohabitat types are defined by their hydromorphologic units (called HMUs, e.g., pools, riffles, and rapids), and by their hydraulic and cover characteristics.

Since the distribution of HMUs changes as a function of flow, the mesohabitats are mapped under multiple flow conditions at representative stretches of the river. The independent biological data (e.g., fish observations) are collected in selected mesohabitats, and are imported to SIM-Stream Software where the relationship between fish and habitat distribution is calculated with multivariate statistics.

The software applies these functions to compute habitat suitability in areas that have not been biologically sampled. The wetted area suitable for a species is determined for all surveyed flows and interpolated for unmeasured conditions. The software also performs habitat time series analyses that describe temporal habitat patterns necessary to support selected fauna.