Master Plan Development - City of Boca Raton

City of Boca Raton Stormwater Management Master PlanDrainage BasinC-15 WatershedA portion of the City is within the SFWMD C-15 Basin. The drainage areas discharging into theL-40, L-41, and L-42 Canals west of Military Trail, or that discharge directly into the C-15 Canalupstream of the S-40 structure are within the C-15 Basin.Hillsboro WatershedThe Hillsboro Watershed within the City is that area that ultimately drains to the freshwaterportion of the Hillsboro Canal (upstream of the G-56 Structure). This area is in the west centralarea of the City and discharges to the Hillsboro Canal via the LWDD E-2 Canal outside the Citylimits (not shown).Figure 5 provides the graphic representation of the delineated watersheds. Please note that thewatersheds extend beyond the City limits, but were only reviewed and revised within the Citylimits.Once the five major watersheds were delineated, a comparison was made to previous/otherdelineations (SFWMD, NPDES, and DEP). Figure 6 shows the five major basins, overlaid withthe previous basin delineations. The two areas where the SFWMD drainage basin delineationdiffers most notably are: between Military Trail and Dixie Highway, north of Yamato Road; and,west of Dixie Highway, south of Glades Road. The area most notably difference from theNPDES basin delineation is the area west of Dixie Highway, south of Glades Road. Finally, themost notable difference from the DEP delineation is the north-south boundary between theICWW and E-4 basins and the C-15 and E-3 basins.The DEP uses their basin delineations in the water quality modeling that is conducted as part ofthe TMDL program. Therefore, we recommend that the City provide the updated watersheddelineations for DEP’s consideration in the very near future.B. Major OutfallsA requirement of the City’s MS4 NPDES permit is the identification of major outfalls to Watersof the State and their associated drainage areas. A major outfall is defined as a discharge pipe of36" or larger, or a discharge pipe that serves a drainage area 50 acres or larger in size. The City’smajor outfalls were determined by first identifying the pipes within the City’s stormwaternetwork that are 36" or larger. Following this, drainage areas that discharge to Waters of theState were delineated. There were no drainage areas of 50 acres or larger discharging from a pipeless than 36” in size. There are 23 major outfalls within the City; shown on Figure 7. Eight ofthe 23 outfalls discharge stormwater from only PBC roadways; however, they have been includedbecause the City’s stormwater network information identifies the City as the owner of the outfallstructures. The identification number shown for each outfall basin in Figure 7 corresponds tothe entries in Table 3. This table provides a summary of the outfall basin information.L/bocaswmp/a6016.01/InterimReport 11-27-07/r02Page 10MOCK•ROOS