Every flood can be different as far as the spawn is affected goes, below is a post from Crappie Pappy from a while back which I think sums it up pretty well. Also there is a biologist report about flooding and the effects on the spawn though it is based on a different type of fish there is similarities.
https://www.crappie.com/crappie/main...fect-spawning/
Here's a good summary of the impact of high flows during spawning season from the Maryland DNR website. Although this is about the upper Potomac, it should apply generally to any river or stream smallmouth habitat.
Fisheries biologist John Mullican sent us some insight into how heavy river flows can affect smallmouth bass spawning success. There are many factors that come into play that can determine the success of each years spawn. River environments are less stable than lakes or impoundments and, as a result, year class strength can be highly variable from one year to the next. River smallmouth bass produce the strongest year classes during springs with average, relatively stable flows. Although bass can adapt and change nesting areas under low or high water flows, average, stable flows usually offer a greater abundance of spawning habitat.
High water events during May and June have the most impact on the spawning success of smallmouth bass. Extremely high flows (right now) will cause bass to abandon nests to seek refuge from the current and the current's scouring action can destroy nest/eggs. Many smallmouth were actively spawning when this most recent high water event occurred. Some of these bass will attempt to renest during May when conditions become more favorable. Similar flooding conditions in June can result in high mortality of the young fry. I my opinion, based on the current conditions in the Potomac, the early spawning smallmouth will be largely unsuccessful. If the later spawning bass are successful, I expect young-of-year smallmouth this summer to be below average in size.
The year class strength of Potomac River smallmouth bass has been monitored annually since 1975. Using a 30' seine nearly 100 hauls are taken at a dozen or more sites from Cumberland to Seneca during July. The abundance of young smallmouth is expressed as the geometric mean per haul. The Potomac had very stable flows during 2007 and the river produced the largest hatch ever recorded during the 33 years of monitoring. However, during the spring of 2008 a high water event occurred on May 15. The bass were smaller than average during our survey and the overall hatch was slightly below average. I expect a below average hatch this spring as well.