Can we please revisit the assumptions in the additional storage routines.
In a world where everyone has access to accurate property location data, via customer seed points and subcatchments can be any shape or size. The distances between properties and sewers can be much more accurately determined in the calculation than is currently the case, based on the existing A/4L.
The calculation also makes no allowance for private inspection chambers, which in many instances would provide more volume than the pipe.
Two versions of the equation driven by a new field in the subcatchment would also be better allowing lateral connections as now, and section 24 connections, derived from the distance between the furthest property from the receiving manhole.
