Dam Breach Analysis of Ponds in series

[Ekenny_G]

I am tasked with performing dam breach analysis of two ponds in series. That is, the ponds are nested together, right next to each other. The upstream dam outlets directly into the downstream pond.
if the upstream dam fails, the water will spill down to the downstream pond before being released slowly thru a riser structure.
How do I model this condition? Can I use TR-20 to evaluate the PMF (20.7 in-24hr) assuming upstream dam failure results in the upstream watershed contributing to the downstream pond?
Would this be a conservative approach compared to other methods?

 

[cvg]

[ul]
[li]assume full US reservoir[/li]
[li]perform a dam breach analysis of the US dam[/li]
[li]route that hydrograph through the DS reservoir (assuming a full reservoir starting condition in the DS dam)[/li]
[/ul]