The Probable Maximum Precipitation (PMP) is theoretically the greatest depth of rainfall for a given duration that is physically possible over a given size storm area at a particular geographic location. As a small-size, high-hazard dam, Dam 3 is required to pass a minimum 75% of the PMF according to State criteria. However, Dam 3 is only able to pass 26.5% of the PMF classifying it as hydraulically inadequate.
As a result, the city initiated design of improvements in 2015 to bring the dam into TCEQ compliance. The proposed modifications include: removing various trees from the embankment, installing a 90-ft wide concrete emergency spillway along the left (east) end of the dam, armoring both sides of the inlet and discharge channel of the dam with rock riprap, and installing a 3-ft wide drainage swale along the left abutment of the emergency spillway to divert localized drainage into Oyster Creek.