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 detention pond temporarily stores stormwater runoff and slowly releases it through a specially designed outlet or control structure. Detention ponds typically are designed to drain completely within a few hours or days.