Grant Witheridge is the principal of Catchments & Creeks, and a leading authority in Hydraulics, Stormwater Management, Waterway Management, and construction site Erosion & Sediment Control.

Grant Witheridge is a retired civil engineer with both Bachelor and Masters degrees from the University of NSW (UNSW). He has over 40 years experience in the fields of hydraulics, stormwater management, creek engineering, and erosion & sediment control, during which time he has worked for a variety of federal, state and local government bodies, and private organisations.

Grant commenced his career at the UNSW Water Research Laboratory operating physical flood models of river floodplains. He later worked for Brisbane City Council on creek engineering and stormwater management issues. He currently works (at his leisure) through his business trading name of ‘Catchments & Creeks’.

Grant is the principal editor of the revised Queensland Urban Drainage Manual (2007, 2013 & 2017), Brisbane City Council’s Natural Channel Design and Creek Erosion guidelines; the IECA (2008) Best Practice Erosion & Sediment Control documents, and the 2002 engineering guidelines on the Fish Passage Requirements for Waterway Crossings.

During the period 1995 to 2017, Grant conducted 590 training courses on various topics attended by some 9,800 participants. In 2009 Grant was presented with the inaugural ‘Neville Gibson Award’ for services to the stormwater industry by the Queensland Branch of the Stormwater Industry Association. In 2010 Grant was honoured with the ‘Sustained Contributor Award’ for 2009 by the International Erosion Control Association (USA).​