As our cities and towns increase in both extent and density there is a continuing increase in hard, impervious surfaces and subsequent loss of green spaces.  If left unmanaged, this increase in urbanisation can result in worsened flood levels due to increases in peak runoff and runoff volumes. Additionally, it can result in worsening water quality in our waterways through the transportation of additional total suspended solids, nitrogens and phosphorous which can silt up the rivers and result in algae blooms and other undesirable effects in our natural systems.

Due to these problems government agencies are now routinely looking at ways to improve the health of the systems they manage and require appropriate management of these issues by land developers.