No worsening is not a thing

Abstract

In Queensland, there is no Statutory Law specifically managing discharge of urban stormwater. Rights and responsibilities relating to stormwater discharge are largely managed through Common Law. Under Common Law, the lawfulness or otherwise of discharge is assessed by considering whether or not the discharge has the potential to create nuisance. And Courts interpret “nuisance” to be something substantive having quantifiable costs. The Queensland Urban Drainage Manual (QUDM) is the “bible” for stormwater design in Queensland (and in other parts of Australia and internationally). Although not a statutory document, QUDM is referenced in most Local Authority Planning Schemes. Early editions of QUDM introduced the concept of “Lawful Point of Discharge”. However, LPOD was often misinterpreted as requiring “no worsening” (post-development stormwater discharge characteristics compared to existing). Many approving authorities add insult to injury by applying very pedantic interpretations of “no worsening”, effectively requiring no change in post-development runoff behaviour compared to predevelopment. “No worsening” is a substantially more onerous requirement than the general requirement in law for “no nuisance”. The real situation in law is that changes to runoff behaviour are acceptable provided that the changes do not result in nuisance. The recently released QUDM 4th edition includes an extensive re-write of the section on lawful discharge and nuisance to remove the misinterpretation and incorrect reliance on “no worsening” of runoff behaviour when considering development proposals. The re-write better explains concepts of nuisance and clearly notes that the “Lawful Point of Discharge” test is satisfied if a proposal does not create nuisance on downstream properties or infrastructure. In managing urban sprawl, it is important that the land bank is used efficiently.

Applying no worsening (ie no change) requirements to post-development discharge complicates, delays, adds unnecessary costs to, or results in refusal of, otherwise acceptable development proposals. Correctly applying nuisance criteria for lawful discharge removes an unnecessary impediment to development. This paper shows, using specific project examples, that development runoff changes (ie “worsening”) can be entirely acceptable