answers from Chicago on. Very tiny bugs coming up the drain that hop a little are probably springtales...I goggled tiny little bugs that hop when I first encountered them and that's what came up.
Detention basin. A detention basin or retarding basin is an excavated area installed on, or adjacent to, tributaries of rivers, streams, lakes or bays to protect against flooding and, in some cases, downstream erosion by storing water for a limited period of time.
The difference in the maximum and retention elevations in the pond is the detention volume. With this method, the detention volume is stacked on the retention volume. Both wet and dry ponds can be configured in this way.