The flows in the accompanying files were corrected after the Little Conestoga Creek Act 167 Storm Water Management Plan was published. There was an error in the "GeoGuide" Arc Macro Language (AML) program for Arc/Info that was used to create the TR20 input files. GeoGuide was created by Innovative System Developers, Inc. of Columbia Maryland, and is no longer available. The AML was encrypted, so there was no way of analyzing the program to determine how the error ocurred.

The programming error resulted in the accumulated flow being routed through the longest channel in each subarea, regardless of whether it was the main channel or not. For example, if the main channel cut across the the corner of a subarea for a distance of 200', but there was another minor channel through the subarea with a length of 1,000', the GeoGuide AML assumed that the main channel was 1,000 feet long. This resulted in an error where the stream storage was too high. Since TR20 routes the flows through each stream reach to account for the storage volume in the stream, the resulting flows were too low.

The published flows are lower than the corrected flows, because of the extra storage volume incorrectly calcualted in the stream reaches. The entire Little Conestoga Creek watershed is scheduled to be redone in approximately 2008 or 2009.