1. Potomac Ridge Stormwater Management Project
Millions have lived without love. No one has lived without water.
Turkish businessman, 1998
October 7, 2013 Public Meeting
Montgomery County Department of Environmental Protection
Watershed Management Division

2. Today’s Agenda Introductions
Paul Bogle – Senior Engineer, Montgomery County DEP
Darian Copiz – Watershed Planner; Montgomery County DEP
Doug Streaker – Project Engineer; Biohabitats
Jeff Blass – Project Designer; Charles P. Johnson Engineering
Background Information – Why County is Doing This
Potomac Ridge Stormwater Management Overview
Project Objectives
Project Costs and Benefits
Design and Permitting Timeline
What to Expect During Construction

3. Sources of Water About 97% is salt water About 2% is frozen
Only 1% is available for drinking water
95% from groundwater across the Country
32% from groundwater, 68% from surface water in Maryland
Potential for greater impacts from runoff in Maryland
Drinking water protection and urban nonpoint source pollution. Materials on page 50 and 51 of the Resource Packet.
About 97% is salt water on the earth. 2% is in the ice caps. Only the remaining 1% is available for drinking water. Of this 1%, groundwater accounts for about 95% of the nation's freshwater resources, eventually flow into surface water bodies. It can bubble out of the ground as a spring or it can be pumped from wells.
In Maryland, about 68% of the population is served from surface sources, the remainder from wells, either individual or community systems.
Do you know where your household drinking water comes from?
Rivers, lakes, reservoirs, springs, and groundwater wells.
Aquifers: underground rivers of water formed from water that seeps from the land surface through the soil layers and becomes trapped between rock formations.

4. Montgomery County, MD 500 sq. miles 1,000,000 people
11/2/2011
Montgomery County, MD
500 sq. miles
1,000,000 people
Second only to Baltimore City within Maryland in average people per square mile
184 languages spoken
About 12% impervious surface overall
About the size of Washington DC
Over 1,500 miles of streams
Two major river basins:
Potomac
Patuxent
Eight local watersheds
District of Columbia
Brief history and tidbits about MoCo.
EXPLAIN impervious
Potomac 88% of MC
Patuxent 12% of MC
Of the 184 languages spoken the top 5 non English spoken are: Spanish, Chinese (Mandarin), Korean, Vietnamese, Amharic (Ethiopia)
Impervious: Not allowing water to soak through the ground.

5. What is a Watershed?
A watershed is an area from which the water above and below ground drains to the same place.
Different scales of watersheds:
Chesapeake Bay
Eight local watersheds
Neighborhood (to a storm drain)

6. Volume/Timing of Runoff
11/2/2011
What is Runoff?
Water that does not soak into the ground becomes surface runoff. This runoff flows over hard surfaces like rooftops, driveways and parking lots collecting potential contaminants and flows:
Directly into streams
Into storm drain pipes, eventually leading to streams
Into stormwater management facilities, then streams
Brief history and tidbits about MoCo.
EXPLAIN impervious
Stormwater is water that originates from storms… becomes runoff
Two Major Issues:
Volume/Timing of Runoff
Water Quality

7. What is the County doing to protect our Streams?
11/2/2011
What is the County doing to protect our Streams?
Must meet regulatory requirements
Federal Clean Water Act permit program
MS4 = Municipal Separate Storm Sewer System
Applies to all large and medium Maryland jurisdictions
County programs
Restore our streams and watersheds
Add runoff management
Meet water quality protection goals
Reduce pollutants getting into our streams
Educate and engage all stakeholders
Individual actions make a difference
Focus on watersheds showing greatest impacts
Federal Clean Water Act NPDES: National Pollutant Discharge Elimination System MS4: Municipal Separate Storm Sewer System Permit
MS4 Permit sets priorities for all Watershed 7

8. MS4 permit, what is it? Montgomery County is responsible for:
What goes into our storm drain pipes
What comes out of them
What flows into the streams
Requires additional stormwater management for 20 percent of impervious surfaces (4,292 acres = 6.7 square miles). That’s about three times the size of Takoma Park.
That’s equivalent to 3,307 football fields!

9. Project Selection Ponds constructed in early 1980s
Located in a key watersheds (Muddy Branch, Watts Branch) for pond retrofits
Ponds are at or near the end of service life
Meet current safety and design standards
Opportunity for water quality treatment and ecological benefits

10. Project Location
Potomac
Ridge

11. Rich Branch (Muddy Branch)
Potomac Ridge
10876
Rich Branch (Muddy Branch)
10887
10891
Can add own photo for your own projects.
10847
Sandy Branch
(Watts Branch)

12. Project Objectives STORMWATER MANAGEMENT STREAM PROTECTION MAINTENANCE
Add permanent pool for water quality where feasible
STREAM PROTECTION
Modify outlet works to better regulate pond discharge and protect Sandy Branch and Rich Branch streams
MAINTENANCE
Replace existing risers with water-tight structures
Replace dam embankment or install impervious liner
Install internal drain in downstream embankments
AESTHETICS/ENVIRONMENT
Landscape the pond to improve aquatic habitat and aesthetics
Augment existing environmental features such as forest and wetlands where possible
Can add own photo for your own projects.

13. Stormwater Pond Drainage Areas
60.4 Acres
58.8 Acres
25% Impervious
16% Impervious
Pond 10876
Pond 10891
7.9 Acres
47.3 Acres
22% Impervious
20% Impervious
Can add own photo for your own projects.

14. Pond 10847 Stormwater Management Dry Pond 8’ High Earth Embankment Dam
Adjacent residential properties
Does not meet current SWM requirements to achieve any MS4 credit.
Long drainage swale inflow to north end.
Existing Metal Outlet Structures
Large Outlet Control Orifice
Embankment Dam
Can add own photo for your own projects.
Concrete Inflow Channels

15. Pond 10847 Can add own photo for your own projects.
Proposed Pond Access
Re-build Existing Embankment
Can add own photo for your own projects.
Improve Existing Swale

16. Pond 10876 Stormwater Management Dry Pond 7’ High Earth Embankment Dam
Metal riser structure is not in compliance with current standards
Stormwater Management Dry Pond
7’ High Earth Embankment Dam
Adjacent to County Road
Does not meet current SWM requirements to achieve any MS4 credit.
Erosion at Outfall
Can add own photo for your own projects.
Facility is undersized for drainage area

17. Pond 10876 Can add own photo for your own projects.
Install Infiltration Basin
Re-build Embankment
Can add own photo for your own projects.
Access from Dufief Mill Road

18. Pond 10887 Stormwater Management Dry Pond
Metal riser structure is not in compliance with current standards
Stormwater Management Dry Pond
10’ High Earth Embankment Dam
Existing Pedestrian Path Across Embankment
Does not meet current SWM requirements to achieve any MS4 credit.
Concrete Channels Prevent Facility from Operating Properly per Current Standards
Can add own photo for your own projects.
Access from Grey Colt Drive

19. Pond 10887 Can add own photo for your own projects.
Remove Existing Inlet/Outlet Structure and Provide Additional SWM Treatment
Access from Grey Colt Drive
Can add own photo for your own projects.
Convert Downstream End of Facility to Wet Pond
Re-build Embankment

20. Metal riser structure is not in compliance with current standards
Pond 10891
Metal riser structure is not in compliance with current standards
Stormwater Management Dry Pond
8’ High Earth Embankment Dam
Does not meet current SWM requirements to achieve any MS4 credit.
Available room for wet pond and potential bioretention terraces
Can add own photo for your own projects.
Concrete Channels Prevent Facility from Operating Properly per Current Standards

21. Pond 10891 Can add own photo for your own projects.
Potential for Terraced Bioretention along sides of facility
Access from Appaloosa Way
Re-build Embankment
Can add own photo for your own projects.
Convert Downstream End of Facility to Wet Pond

22. Project Objectives - SWM
All ponds - 24-hour detention for stream channel protection
Ponds 10887, Permanent Wet Pool
Pond – Dry Pond
Pond Convert to Infiltration area/Dry Pond Combination
Pond – Install bioswale in-lieu of inlet/outlet structure at Northeast inflow point.
Pond – Potential bioretention terraces
Can add own photo for your own projects.

23. Project Objectives - Streams
Stream protection
Modify outlet works to better regulate pond discharge and protect Rich Branch and Sandy Branch
Achieve partial to full channel protection volume requirement (depending on pond)
Can add own photo for your own projects.

24. Project Objectives - Maintenance
Replace existing risers with water-tight structures
Install impervious liner on dam embankments
Install internal drain in downstream embankments
Can add own photo for your own projects.

25. Project Objectives - Aesthetics
Landscape all facilities with native vegetation to improve aquatic habitat and aesthetics
Can add own photo for your own projects.

26. Project Costs
Financial – estimated cost of $2.3M financed through MCDEP CIP Program using funds generated through the Water Quality Protection Charge
Recreational – temporary construction impacts to pedestrian path on top of embankments at Pond
Forest – tree clearing for to comply with state dam safety laws along the downstream toe of the dam.
Traffic – construction traffic enter and exit roadways Monday – Friday, 7AM to 4PM
Neighborhood – construction traffic and noise will typically occur Monday – Friday, 7AM to 4PM
Can add own photo for your own projects.

27. Project Benefits
Water – improved water quality and stream water temperature through better management of runoff
Environmental – reduced downstream discharge allows for natural self-repair of stream channel. Increased aquatic and riparian habitat through landscaping and reforestation.
Recreational – increased aesthetic appeal of ponds
Maintenance – safer operating structure that will require minimal structural maintenance in future.
Can add own photo for your own projects.

28. Estimated Design and Permitting Timeline
Design – September 2013 – March 2014
Approvals – March/April 2014
Permits – April 2014
Bidding –May 2014
Construction – June - August2014
Can add own photo for your own projects.

29. What to expect during construction
Duration
Approximately 3 months
Construction Hours
Monday through Friday, 7AM – 4PM
Safety
Open sides of site will be fenced with orange construction safety fence to separate construction from residents.
Traffic
Minor impacts to traffic from entering and exiting construction traffic and contractor parking during the day.
Noise
Contractor is required to comply with Montgomery County Noise Ordinance – site elevation will help alleviate noise pollution.
Sediment
Contractor will be required to comply with Montgomery County Sediment Control Permit and not track dirt onto roads
Can add own photo for your own projects.

30. Questions? For more information:
Doug Streaker, ,