Runoff after property development on previously undeveloped land should be at least similar in volume and quality after the site has been developed.  Runoff from redevelopment sites should be no worse than previously existing and should, when possible decrease in volume and increase in quality.
	This figure shows the runoff hydrographs before and after traditional development.  Flow (in cubic feet per second) is on the vertical axis and time is on the horizontal axis.  Q is discharge or flow. Qb is the peak discharge before development. The peak discharge occurs at time Tb.  On this graphic, the discharge after typical development is shown as Qa.  Notice that the peak occurs more quickly (Ta is less than Tb) and the peak flow itself is much higher, meaning an earlier, higher discharge volume. This is due to the fact that after traditional development there is usually increased impervious surface and stormwater runoff has been channeled or directed to flow more quickly off site.
	The goal of Principle Five is to design the stormwater management for the site so that the peak discharge after development is closer to the peak discharge before (Qb = Qa).
	Note: Storm water regulations may now be in place that were not there when the property was developed originally.  The Phase II storm water regulations call for implementation of post-development runoff controls.