Outfall Repairs (P509948)

  • Category: Conservation of Natural Resources
  • Sub Category: Storm Drains
  • Administering Agency: Transportation (AAGE30)
  • Planning Area: Countywide
  • Date Last Modified: 12/23/13
  • Required Adequate Public Facility: No
  • Relocation Impact: None
  • Status: Ongoing




This project provides for the repair of existing storm drain outfalls into stream valleys. Design of corrective measures is included when inkind replacement of original outfall structures is not feasible. Candidate outfall repairs are selected from citizen and public agency requests. The Department of Environmental Protection's (DEP) Miscellaneous Stream Valley Improvements project generates and assists in rating the outfalls, which are identified as that project expands into additional watersheds.

Cost Change

Increase due to the addition of FY19-20 to this on-going level of effort project


Collapsed storm drain pipe sections, undermined endwalls, and eroded outfall channels create hazardous conditions throughout the County. The course of drainage could be altered endangering private property or public roads and speeding the erosion of stream channels. Erosion from damaged outfalls results in heavy sediment load being carried downstream that can severely impact aquatic ecosystems and exacerbate existing downstream channel erosion. As part of its watershed restoration inventories, DEP identifies storm drain outfalls that are in need of repair in County stream valleys and respective watersheds. As this program expands to include additional watersheds, each outfall is categorized and, where damaged, rated. A functional rating and evaluation process is used to prioritize each outfall.


The number of outfall locations being repaired per year varies based on the severity of the erosion and damage, the complexity of the design, and the complexity of the needed restorative construction work. Completed outfalls in FY12-13: Emory Grove Road, Bluehaven Court, Circle Drive at Spring Drive, Prathertown Road, Marseille Drive, Wayne Avenue at Sligo Creek Parkway. Scheduled for repairs (FY14 - beyond): 11101 Schuykill Road, 10668 Maple Leaf Drive, 20232 Maple Leaf Court, 1301 Dilston Place, 9112 Falls Bridge Lane.

Fiscal Note

Funding source changed from General Obligation Bonds to Water Quality Protection Charge (FY15 and FY16) and Water Quality Protection Bonds (FY17-20).


A pedestrian impact analysis has been completed for this project.

Expenditures will continue indefinitely.


Department of Environmental Protection, Maryland-National Capital Park and Planning Commission, Maryland Department of the Environment, United States Army Corps of Engineers, Montgomery County Department of Permitting Services, Utility Companies, Miscellaneous Stream Valley Improvements