Balancing Wetland and Balancing Wetland and Stream Preservation with Stream Preservation with

Stormwater Management: A Stormwater Management: A Case StudyCase Study

Presentation forNational Association of Environmental Professionals 39th Annual Conference

St. Petersburg, Florida

April 8, 2014

Andrew T. Der & Associates, LLCEnvironmental Consulting

1000 Fell Street | Baltimore, MD 21231

1.410.491.2808 | AndrewTDer@comcast.net

Habitat Avoidance – can be - Habitat Avoidance – can be - InsufficientInsufficient

What HappensWhat Happens

Secondary Impacts = New Secondary Impacts = New Construction SWM criteriaConstruction SWM criteria

Disturbance to Surface water resources

• State nontidal waters and wetlands including 100 year floodplain and water quality criteria

• State tidal waters and wetlands

• Federally regulated waters of the United States

Disturbance to Land (nonpoint source pollution)

• State stormwater management regulations – includes delegated point and nonpoint source federal criteria

• State and local erosion and sediment control criteria

• Special state tidal water criteria

Classification of State Waters in Classification of State Waters in MarylandMaryland

• Use I & I-P: Water Contact Recreation and Protection of Aquatic Life

• Use II: Shellfish Harvesting Waters

• Use III & III-P: Natural Trout Waters

• Use IV & IV-P: Recreational Trout Waters

State Water Quality StandardsState Water Quality Standards

Numerical

• Dissolved Oxygen, Temperature, pH, Turbidity, Fecal Coliform, Toxics

Narrative include CWA

•...Protection of Aquatic Life ...Fishable ...Swimmable...Includes EPA Anti-Degradation Policy (ADP):

“...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...”

What is a Best Management What is a Best Management Practice (BMP)?Practice (BMP)?

BMPs are policies, practices, procedures, or structures (engineered practices) implemented to mitigate the adverse environmental effects on surface water quality resulting from rain water runoff. BMPs are categorized as structural or non-structural.

• Early Planning/ Avoidance

• “Low Impact Development”, or “Better Site Design”, or “Environmental Site Design”

• Local stream buffers and setbacks

• Minimize or disconnect impervious surfaces sheet flow, open section pavement

• Devices or engineered practices (ponds, bioretention, etc.)Most significant factor affecting performance is construction and

maintenance

Hierarchy of Engineered Hierarchy of Engineered PracticesPractices

Smaller Volumes“First Flush”Preferred and most compatiblewith ESD at-source and/orpretreatment 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 VolumesWhen preferred is

Insufficient for quantity and quality

• Stormwater Ponds– wet pond– wet ED pond– dry ED pond (for cold

water w/ pre-treatment)– multiple pond system

• Stormwater Wetlands– shallow marsh– ED shallow wetland– pond/wetland systems

Location of Example Project Location of Example Project AreaArea

Location of Project AreaLocation of Project Area

Watershed and Initial Watershed and Initial Development at Low PointDevelopment at Low Point

Initial Permit Review StepsInitial Permit Review Steps

• Higher Quality Use I-P Water

• Purpose and Need

• Avoidance and Minimization of Waters of the U. S. from Roads, Utilities, and Other Disturbances

• Nonpoint Source Pollution Management: Quality

• Stormwater Management (SWM): Quantity

• Coordination with Local Authorities, NGOs, and Stakeholders

• How to Address ADP and SWM

Apply Hierarchy of SWM Apply Hierarchy of SWM Preferences to Site CharacterPreferences to Site Character

• Vegetative buffers, disconnects, open section pavement

• Infiltration Practices if Soils Allow

• Bioretention, Swales, Wetland Filtering

• Retention or Extended Detention Pond with Wetlands (to include quantity management)

Proposed Proposed Site-specificSite-specific Mitigation and BMP’sMitigation and BMP’s

• Stream/wetland impacts limited to necessary roads/utilities

• In-stream 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

BMPs and Mitigation – Forest BMPs and Mitigation – Forest and Wetlands – Work with Siteand Wetlands – Work with Site

BMPs and Mitigation - BMPs and Mitigation - Maximize Site CharacterMaximize Site Character

BMPs and Mitigation - Pond BMPs and Mitigation - Pond and Wetlands Managementand Wetlands Management

BMPs and Mitigation – Impact BMPs and Mitigation – Impact Avoidance and Wetland Avoidance and Wetland FiltrationFiltration

BMPs and Mitigation - BMPs and Mitigation - Sensitive ResourcesSensitive Resources

BMPs and Mitigation - BMPs and Mitigation - Transition HabitatTransition Habitat

BMPs and Mitigation - SWM & BMPs and Mitigation - SWM & LandscapingLandscaping

BMPs and Mitigation – SWM BMPs and Mitigation – SWM and Landscapingand Landscaping

BMPs and Mitigation – Urban BMPs and Mitigation – Urban AreasAreas

BMPs and Mitigation – Urban BMPs and Mitigation – Urban AreasAreas

BMPs and Mitigation – Urban BMPs and Mitigation – Urban AreasAreas

BMPs and Mitigation - Stream BMPs and Mitigation - Stream Stabilization and RestorationStabilization and Restoration

• Can be effective watershed sediment control practice

• Can be local approval

requirement

• Can be a traded credit

• Can be out-of-kind wetland mitigation

Public & NGO InvolvementPublic & NGO Involvement• Public Notice

• Waters may have Use III or IV (higher quality trout water) potential

• Temperature and ponds potential concern

• EPA Antidegradation Policy may apply

• Implemented stream Rapid Bioassessment

• Findings - no Use III or IV standards but higher quality Use I

Additional Mitigation and Additional Mitigation and Water Quality Management Water Quality Management PracticesPractices

• Water Quality Monitoring Plan

• Stream Reach Temperature Model and Percent Contribution of “QED” 2, 10 year event to Stream Flow

• Maximum 20% Diversion Base Flow

• Shade Planting of SW Conveyance and Management Areas

•Toe Drain Pipes Under Embankment Fill

Stream and Water Quality Stream and Water Quality MonitoringMonitoring

Can be used for state Watershed Compliance

Can be used for state natural resource studies

Preconstruction, construction and post-construction

Macroinvertebrate studies(more common examples are WWTP & mining requirements)

Chemistry

Geomorphology

Groundwater

Primary Monitoring Primary Monitoring ComponentComponent

Historic Bioassessment DataHistoric Bioassessment Data

Rapid Bioassessment Metric Comparisons to Pre-Construction ScoresYear ST2 ST6 ST101993 Non Impaired ** Non Impaired **1994 Non to Mod. Impaired Non Impaired Non Impaired **1995 Non to Mod. Impaired Non to Mod. Impaired Non Impaired1996 Non to Mod. Impaired Moderately Impaired Non to Mod. Impaired1997 Non to Mod. Impaired Non to Mod. Impaired Moderately Impaired1998 Moderately Impaired Non to Mod. Impaired1999 Moderately Impaired Moderately Impaired Moderately Impaired2000 Moderately Impaired Non to Mod. Impaired2001 Non to Severely Impaired Moderately Impaired Non Impaired2002 Non to Mod. Impaired Mod. to Severely Impaired

** Non Impaired value is given to the first (reference) date for comparison purposes;

the streams on those dates are not necessarily truly non-impaired.

Historic Dissolved Oxygen Historic Dissolved Oxygen DataData

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.

Historic Temperature DataHistoric Temperature Data

Piney Branch Instream Peak TemperaturesStations 2, 6 and 10

0

5

10

15

20

25

30

35

1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002

Year

Tem

pera

ture

(o

C)

ST. 2 ST. 6 ST. 10

Lessons LearnedLessons Learned

• Basis for “how we do it now”

• Basis for groundbreaking county Special Protection Area legislation

• Basis for local, state, federal coordinating committees and public processes

• Basis for initial findings for CWA Section 402 Phase I MS4 NPDES Municipal Permit Compliance