Presentation for Center for Watershed Protection 2021 National Watershed Stormwater Conference

1. Balancing Nonpoint Source Water
Quality Management with Wetland and
Stream Preservation: Lessons Learned
Presentation for
Center for Watershed Protection 2021 National
Watershed Stormwater Conference
Virtual
Andrew T. Der, C.E.P.
Thursday April 15, 2021
Andrew T. Der & Associates, LLC
Environmental Consulting
1000 Fell Street | Baltimore, MD 21231
410.491.2808 | AndrewTDer@comcast.net

2. Contents
- Past and Current Maryland Water Resource Regulation
- Past and Current Maryland Stormwater Management
(SWM) Principles
- Initial Project Site Description
- Agency Review Process
- Proposed Past and Current Best Management Practices
and Mitigation
- Past Water Quality Conditions from Public Interest
Process – and Current Outcomes

3. Summary of Maryland
Water Resource
Regulation

4. Surface Water Regulation
Past and Present
• 1948 Federal Water Pollution Control Act with 1972
amendments - Clean Water Act (CWA) - most influential
environmental law in history by catalyzing other ancillary state
and local programs
• Established the basis for regulating pollutants/discharges into
the Waters of the U. S. (WUS) giving the U.S. EPA authority to
implement pollution control programs directly or by delegation
or general permit to other agencies or states
• Emphasizes “…restore and maintain the chemical, physical,
and biological integrity of the Nation’s waters…” – “…make all
U.S. waters fishable and swimmable…”
• Gradually transitioned from point source strategies to
nonpoint source – this is key

5. Surface Water Regulation
Past and Present
• The CWA Sections most affecting nonpoint source water
management and WUS, including wetlands, at the time of the first
of numerous projects (1990 into 2015) were:
– Section 404 requiring a federal permit from the U. S. Army
Corps of Engineers (COE) to discharge material
– Section 401 state Water Quality Certification (WQC) from the
Maryland Department of the Environment (MDE) requiring the
state certify that a 404 permit will not violate Maryland’s water
quality standards
• Stormwater Management (SWM) of the nature required today were in
their infancy - the above were the only true processes in place then
• The EPA Antidegradation policy (ADP) via the 401 WQC process
was the primary water quality management instrument for on-site SWM
at that time but only when WUS impacted – stating: “…to accomplish
the objective of maintaining existing water quality…nonpoint sources
shall achieve all cost effective and reasonable best management
practices for nonpoint source control…”

6. Surface Water Regulation
Past and Present
• Other CWA Sections in play today (but not back then)
include:
–- Section 402 National Pollutant Discharge Elimination System
(NPDES) through Phase I and II implementation regulating pre-
existing and new construction point and nonpoint source pollution
by EPA “delegation” to states through General Permits
– New construction is authorized under a Notice of Intent (NOI)
process concurrent with MDE SWM plan approval
– Existing pre-regulation and older municipal discharges are
authorized by issued Municipal Separate Storm Sewer System
(MS4) programmatic permits with retrofit, restoration, and
remediation conditions – and is the only formal permitting to
remediate legacy water quality impairments

7. Surface Water Regulation
Past and Present
• Other CWA Sections in play today (but not back
then) include:
– Section 303 requires states to list impaired waters
and develop Total Maximum Daily Loads (TMDL)
for these waterbodies to establish the maximum
amount of a pollutant allowed as a starting point and
planning tool for restoring water quality.
– The largest TMDL is for the entire Chesapeake
Bay, setting the framework today for compliance and
processes through local MDE-approved Watershed
Implementation Plans (WIP) along with any
permitting processes

8. Regulatory Process Project
Timeline
• 1990 – The project permittee applies for a COE Section 404
nationwide general permit along with a Section 401 WQC from
MDE for very minor impacts to WUS – these were the only
authorities in place at the time grandfathering the project from future
new regulatory processes
• Mid-1990s – MDE implements state Nontidal Wetlands and
Waterways (WWP) permitting process regulating nontidal waters
waters via a joint permitting application (JPA) combining it with the
COE 404/401 WQC process - MDE additionally regulates the 100-
year floodplain, the 25.0 foot nontidal wetland buffer, wetland
vegetation clearing, and isolated wetlands not regulated by the COE
• Mid-1990s - COE issues to MDE first Maryland State
Programmatic General Permit (MDSPGP) authorizing impacts to
the state when meeting criteria which, in effect, allows MDE to
authorize many projects on the COE's behalf with federal conditions

9. Regulatory Process Project
Timeline
• Mid-1990s - Maryland Department of Natural Resources (DNR)
implements Forest Conservation Act regulating forests including
mitigation and first programmatic stream buffer setback requirements
• Mid-1990s - MDE implements CWA Section 402, NPDES Phase I and II
programmatically via General Permits
• Mid-1990s to 2007 - MDE refines their SWM program, their SWM
Manual, and implements the 2007 SWM Act integrating ecology with
engineering incorporating Best Management Practices (BMP) by reference
- formalizes Environmental Site Design (ESD) to the Maximum Extent
Practicable (MEP) - compliance is achieved by channel stability and post-
development conditions replicating, to the receiving stream, “woods in good
condition”
• 1992 to early 2000s – the initial project is completed along with first
watershed BMP monitoring effort (was a diver for new state/county
criteria currently in place) followed by subsequent ancillary build-out of
other contiguous properties into 2015 up-drainage in separate phases

10. Other Resource Regulatory
Processes
Just as FYI, disturbance to tidal waters and
land regulated then but did not apply
• Tidal Waters Including Wetlands:
MDE regulates tidally-influenced open and navigable water
and their wetlands through separate process and the COE
via the Section 404 process
• Critical Area Commission for The Chesapeake & Atlantic
Coastal Bays:
The DNR regulates land and impacts including water buffer
setbacks within 1,000 feet landward from Mean High Water
through a delegated local planning overlay process

11. Summary of Maryland
Stormwater Management
Principles

12. Habitat Avoidance Alone is
Insufficient

13. What Happens

14. How SWM is Applied at the
Project Level
Current BMPs were in infancy during first project which drove future
design - BMPs are policies, practices, procedures, or structures that
mitigate the potential effects of stormwater runoff prior to release
into a water. BMPs can be structural or non-structural
- Early planning
- Local stream buffers and setbacks
- Minimize or disconnect impervious surfaces
- Maximize sheet flow and open section pavement
- Then BMP devices (most significant factor affecting
performance is construction and maintenance!)

15. Structural BMPs
Smaller Volumes - try
first
“First Flush” is preferred and most
compatible with ESD at-source
and/or pretreatment quality
control
• Infiltration
– trench/basin
• Filtering
– sand filter/bioretention
• Hydrodynamic Devices above
or underground
– Curb & gutter vortex/filter
basin
• “Newer” Technology
– pervious surfaces/green
roofs
Larger Volumes – if
needed
When preferred is Insufficient
for both quantity and quality
• Stormwater Ponds
– wet pond
– wet ED pond
– dry ED pond (w/pre-
treatment)
– multiple pond system
• Stormwater Wetlands
– shallow marsh
– ED shallow wetland
– pond/wetland systems

16. Water Quality Standards
• Can be numeric and narrative, and basis for sensitive water
requirements
• Needs to maintain the designated uses (e.g. recreation, aquatic
habitat, drinking water)
• Can impose a construction time-of-year restriction in a permit
• Numeric – Dissolved Oxygen, Temperature, pH, turbidity, bacteria,
toxics, etc.
• Narrative - Protection of aquatic life...fishable…swimmable
• Includes Antidegradation (ADP) policy from EPA:
“…To accomplish the objective of maintaining existing water
quality…nonpoint sources shall achieve all cost effective and
reasonable best management practices for nonpoint source control…”
(this was de facto onsite stormwater quality management at that time!)

17. Classification of Maryland
Waters
• Use I & I-P: contact recreation and protection of
aquatic life waters
• Use II: shellfish harvesting waters
• Use III & III-P: natural reproducing trout waters
• Use IV & IV-P: recreational (put and take) trout
waters
• Time of year restriction for instream work

18. Summary of Project Site

19. Location of Project Area

20. Location of Project Area

21. Initial Project at Watershed Low
Point

22. Summary of Agency
Review Process

23. Initial MDE/COE Permit Steps
• County review based mostly on quantity SWM and
completed prior to JPA
• Determined to be higher quality Use I-P water
• Purpose and need documentation
• Avoidance and minimization of WUS from roads, utilities,
and other disturbances
• On-site quality SWM via MDE ADP and WQC required
• Coordination with local authorities, NGOs, and
stakeholders

24. MDE Applies Own SWM
Preferences
• Vegetative buffers, disconnects, open section
pavement
• Infiltration practices if soils allow
• Bioretention, swales, wetland filtering
• Retention or extended detention pond (to satisfy
quantity management requirement) with
wetlands, habitat, and forebays

25. MDE Accepted Site-specific
Mitigation and BMP’s
• Stream/wetland impacts limited to necessary roads/utilities
• In-waters SWM in marginal/poor areas only
• Minimum stream buffer of 100‘ (30.5 meters)
• Wetland mitigation and replanting in cropped riparian buffer areas
• “First flush” stormwater quality management in uplands
• Infiltration/filtration where feasible (permeable soils and depth)
• Primary quantity stormwater management in “horseshoe” pond
• Water pooling areas planted with wetland vegetation

26. Public & NGO Involvement
• MDE Public Notice
• Waters may have Use III or IV trout water potential
• EPA ADP may apply
• Temperature and ponds potential concern
• Implemented trout stocking and sampling
• Findings - no Use III or IV potential but a high quality
Use I

27. Summary of Proposed
BMPs and Mitigation
(foundation for current
principles)

28. Work with Forest and Wetlands

29. Utilize Site Character

30. Stormwater and Wetland
Management

31. Impact Avoidance and SWM

32. Temperature Sensitive Resources

33. Transition Pond Habitat

34. SWM & Landscaping

35. SWM and Landscaping

36. Commercial Areas

37. Small Spaces

38. More Small Spaces

39. A First Stream Stabilization and
Restoration
• One of first then
• Can be effective
watershed
sediment control
practice
• Can be local
approval
requirement
• Can be a traded
credit
• Can be out-of-
kind wetland
mitigation

40. Additional Water Quality
Conditions from Public
Interest – and Outcome

41. Additional Mitigation and SWM
• Water quality monitoring plan
• Stream reach temperature model
• Maximum 20% diversion base flow to ponded
areas
• Shade planting of open stormwater conveyance
areas
• Toe drain pipes under embankment fill for
increased cooler groundwater contribution

42. Stream and Water Quality
Monitoring
One of first then – basis for
County Special Protection Area
Can be used for state
Watershed Compliance
Preconstruction, construction
and post-construction essential
Can be used for DNR stream
data
Included Macroinvertebrate
studies
Chemistry, Geomorphology

43. Primary Monitoring Component

44. Historic Rapid Bioassessment
Data
Rapid Bioassessment Metric Comparisons to Pre-Construction
Year ST2 ST6 ST10
1993 Non Impaired ** Non Impaired **
1994 Non to Mod. Impaired Non Impaired Non Imp
1995 Non to Mod. Impaired Non to Mod. Impaired Non Imp
1996 Non to Mod. Impaired Moderately Impaired Non to M
1997 Non to Mod. Impaired Non to Mod. Impaired Modera
1998 Moderately Impaired Non to M
1999 Moderately Impaired Moderately Impaired Modera
2000 Moderately Impaired Non to Mod. Impaired
2001 Non to Severely Impaired Moderately Impaired Non Imp
2002 Non to Mod. Impaired Mod. to Severely Impaired

45. Historic Dissolved Oxygen Data
Piney Branch Mean Dissolved Oxygen Levels for Stations 2, 6 and 10
0
2
4
6
8
10
12
14
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Year
mg/l
ST. 2 Mean D.O. ST. 6 Mean D.O. ST. 10 Mean D.O. Use I Min. D.O.

46. Historic Temperature Data
Piney Branch Instream Peak Temperatures
Stations 2, 6 and 10
0
5
10
15
20
25
30
35
1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002
Year
Temperature
(oC)
ST. 2 ST. 6 ST. 10

47. Lessons Learned
• Contributed to “how we do it now”
• Final watershed buildout under current criteria occurred up grade of
example project completed in 2010 – 2015 – and show a net gain over pre-
existing conditions
• Contributed to MD SWM Manual and onsite “first flush” Environmental Site
Design (ESD) to the Maximum Extent Practicable (MEP) principles
• Contributed to “cold water” SWM and BMP strategies when waters,
including wetlands, permits are required
• Contributed to the first ever innovative County-level Special Protection
Area legislation
• Basis for future evolving local, state, federal coordinating and public
processes
• Contributed to initial County reporting requirements to MDE to comply with
first CWA Section 402 Phase I MS4 NPDES MS4 Permit to the County