Part II.B.4.e.(9), proposes that waste containers be closed during precipitation events and at the end of the business day, or implementation of similarly effective practices...

While this is an excellent pollution prevention concept and we do not intend to oppose it, it fails, in practice, when we try to implement such practices for large, roll-off dumpsters (e.g., 20- or 30-yard dumpsters), as the waste management industry does not, currently, have the ability to supply covers for these waste containers.  

In the past, when we have attempted similar measures, such as tarps, we've found that following a precipitation event of multiple-inches of rain or heavy, wet snow, the tarps fall into the roll-offs and are unretrieveable without dispensing the stormwater within the dumpsters.

In order to meet this requirement, the construction industry will need explicit guidance on how to meet the second half of this proposed requirement: "...or implementing other similarly effective practices.  Minimization of exposure is not required in cases where the exposure to precipitation will not result in a discharge of pollutants...".   In such a case, and simply as an example, would roll-off dumpsters positioned, without cover, in a sloped area that has containment berms along its lower three sides (the upper side utilized for access by the vendor) be sufficient to meet the "cases where the exposure to precipitation will not result in a discharge of pollutants", particuarly in those cases of dumpster sizes that are unable to be supplied with covers?