Project SD2005-12 ultimately facilitated the application of paleoflood techniques for site investigations along Spring Creek and French Creek, both sites chosen to demonstrate the quality of high-resolution flood chronologies that are obtainable within suitable environments. Extensive reconnaissance efforts prior to the in-depth site surveys ascertained that the same investigative potential exists within many other applicable stream reaches. Again, the detailed stratigraphic analysis of deposits found at these 2 sites, which represent a common environment in Paleozoic carbonate rocks around the periphery of the Black Hills, would allow for interpretation and dating of flood-deposit sequences that could provide long-term chronologies of large flood events with fairly high levels of confidence. Additionally, various other forms of paleoflood evidence might also be collected at the same time to contribute supporting information for many candidate locations. Application of paleoflood techniques on a broader scale would also warrant inclusion of comprehensive hydraulic and statistical analyses. This would require detailed surveys of channel geometry throughout appropriate stream reaches with good slackwater deposits to support in-depth hydraulic analyses necessary for estimating discharges of previous large flood events. Finally, the use of appropriate statistical analytical procedures incorporating infrequent large flood events would be required for the development of new, robust flood-frequency estimates.
Reconnaissance site investigations would provide the most information on the size and frequency of large-scale flows, particularly if focused on the larger Black Hills drainages similar to the Spring Creek and French Creek sites. Most if not all of these larger drainages have candidate sites with high potential for paleoflood analysis. Results using these approaches would be most meaningful for assessing hazards for the majority of populated areas and infrastructure concentrated along the flanks of the Black Hills. Investigations of higher-elevation and smaller drainages would provide important information regarding flood generation processes and controlling factors such as elevation, topography, and geology. Smaller drainages in the higher elevations generally have few flood deposits preserved, but again, reconnaissance during Project SD2005-12 indicated several possible sites for which detailed investigations probably would provide supporting information on flood-frequency and magnitude. Such information would contribute to site-specific flood-frequency analyses as well as frequency analyses on a regional basis.