We're studying the feasibility of restoring aquatic habitat to a 1.2 km (4,000 ft) length of river pool on the Upper Ohio River. Restoration may include adding large river substrate, terracing the river bank, adding perched wetlands, etc. We were wondering if there exists any habitat evaluation model/procedure that would allow us to assess potential benefits holistically, i.e., in a linked, perhaps synergistic fashion. Our evaluation alternatives, at this point, are to use something like time-worn HSI models (e.g., for Smallmouth Bass).
I might go off on a tangent here, but from my experience (or better: from German/European experiences from the last 30+ years) I would say that things linke adding large substrate and terracing the banks are neither necessary nor advisable. They are usually quite expensive and after a larger flood event or two none of it will remain (or it has to be maintained which costs even more money). In Germany the authorities now like to apply an approach that allows for a self-reinforced development of the river morphology. This include removing the bank fixation and often (where necessary) the removal of parts of the topsoil (in order to decrease the height difference between the water level and the floodplain). In many cases large woody debris (or boulders) is also fixated in the riverbed in order to guide the current and promote bank erosion. These combined measures usually do not cost more than 150€/m, while more traditional restoration measures (riverbed modelling, planting of riparian trees, 5-years maintenance and so on) add up to usually up to 2000€/m.
My PhD focused on the evaluation of two such self-reinforced restoration measures with a special focus on the riverbed morhphology and the macrozoobenthos and the results show that these simple measures are very effective in enabling a more natural substrate and habitat dynamic, especially if flood event speed up the process.