Innovative Strategies & Adaptive Restoration Approaches ... · Innovative Strategies & Adaptive Restoration Approaches for Tidal and Nontidal Areas Given Changing Coastal Conditions

Innovative Strategies & Adaptive Restoration Approaches

for Tidal and Nontidal Areas Given Changing Coastal Conditions

reduce vulnerability, rethink management, resilient approaches

Darcy Turner & Joe Berg Biohabitats, Inc.

[email protected]

Envision a world where the earth’s complex living systems are intricately linked and delicately balanced with their surroundings. Where your actions conserve critical habitat; where your project restores ecological processes; or where your footprint regenerates natural systems.

Ecological Restoration Regenerative Design Conservation Planning

Core practice areas

SCIENCES aquatic ecologists terrestrial ecologists restoration ecologists conservation biologists geologists hydrogeologists fluvial geomorphologists foresters soil scientists

Biohabitats’ team

ENGINEERING ecological engineers civil engineers water resource engineers Chemical engineers

DESIGN landscape architects natural resource planners

SUPPORT GIS Technicians CAD Technicians construction inspectors

Biohabitats’ whereabouts

reduce vulnerability, rethink management, resilient approaches

Context: Anne Arundel County, Maryland

Chesapeake Bay Watershed

530 miles of shoreline

Eastern Continental Shelf

(subsidence, post glacial readjustment)

reduce vulnerability

Vulnerability Assessment: (Sea Level Rise Strategic Plan Anne Arundel County, 2011)

vulnerability = susceptibility to flooding (storm surges) and inundation from sea level rise

adverse impact = increased groundwater elevations (sewers, storm drains, wells and septic systems

Scenario 1 0-2 ft inundation

2,193 acres vulnerable 62% are woodlands and wetlands

water lines 26,684 feet sewer lines 89, 092 feet

storm drain pipes 22,880 feet septic systems 5,206

private wells 4,718


6,905 acres vulnerable 56% are woodlands and wetlands

water lines 53,729 feet sewer lines 306,865 feet

storm drain pipes 66,212 feet septic systems 7,238

private wells 7,633


Relevant Key Issues:

(Sea Level Rise Strategic Plan Anne Arundel County, 2011)

Loss of Ecologically Significant Land Shoreline Erosion

Impaired Public Infrastructure Private Well and Septic


1,600 acres of loss of ecologically significant land

Result: increase in shoreline erosion

loss of protection against storm surges increased coastal flooding


4,500 acres of loss of ecologically significant land

Result: increase in shoreline erosion

loss of protection against storm surges increased coastal flooding


Development Potential of Vulnerable Areas:


Chesapeake Bay Critical Area Regulations FEMA Regulations

49,450 acres in Critical Area


2,079 acres of 2.193 acres in critical area 4% of total critical area is vulnerable 94% of inundation acreage is within

FEMA AE Zone (tidal and non-tidal 100-year floodzone)


6,585 acres of 6,905 acres in critical area 13% of total critical area is vulnerable

94% of inundation acreage is within FEMA AE Zone

(tidal and non-tidal 100-year floodzone)


Protection of Coastal Ecosystems: (Sea Level Rise Strategic Plan Anne Arundel County, 2011)

Protection and restoration of high priority shoreline

Acquire lands with program open space or other preservation funds

Target areas for wetland forest mitigation projects

(off-site mitigation for private developers)

Promote conservation easements (resource protection through tax incentives)

rethink management

Reduce Sea Level Rise Impacts:


Revise regulation to discourage the granting of variances and modifications to stream and wetland impacts

Revise the County’s development regulations to increase

stream and wetland setbacks (State Critical Area Commission Regulations)

Evaluate regulatory and non-regulatory recommendations that

could be incorporated into development plan review and approval

rethink management

Living Shoreline Act 2008

CWA MS4 Credits

Annual Shoreline Management Credits* Runoff Reduction Practice Credits**

Regenerative Stormwater Conveyance**

*(MS4 load reductions, MDE approved, under consideration by CBP) **(MS4 load reduction and impervious area treatment credits, adopted by CBP)

resilient approaches (“Adaptive” restoration techniques)

Green Infrastructure - Regenerative Stormwater Conveyance

(stormwater collection and conveyance – ephemeral conditions)

Regenerative Design - Regenerative Gully & Stream Restoration

Living Shorelines

Ecological Engineering

Biomimicry

Provisioning services

Regulating services

Supporting services

Cultural services

ecosystem services water

food (seafood and game), crops, wild foods, and spices energy (hydropower, biomass fuels)

carbon sequestration and climate regulation waste decomposition and detoxification

purification of water and air flood attenuation

crop pollination pest and disease control

nutrient dispersal and cycling seed dispersal

primary production cultural, intellectual and spiritual inspiration

recreational experiences (including ecotourism) Resilient Approaches

Green Infrastructure uses vegetation, soils, and natural processes to manage water and create healthier urban

environments. USEPA

Nature can be harnessed to provide critical services for communities, protecting them against flooding or excessive heat,

or helping to improve air and water quality, which underpin human and environmental health. When nature is harnessed by

people and used as an infrastructural system it's called “green infrastructure.” ASLA

Resilient Approaches

Regenerative Stormwater Conveyance Road-side ‘losing streams’ instead of pipes


Green Infrastructure


Holladay Park Anne Arundel County, Maryland Jabez Branch (receiving stream)

From piped drainage to conveyance that treats and reduces runoff

STORMWATER MANAGEMENT SUMMARY TABLE PHASE 1

Criteria

Volume Required

(cubic-feet)

Volume Provided

(cubic-feet)

Net Difference (cubic-feet)

Water Quality Volume (WQv) 8053 31032 22979

Reccharge Volume (Rev) 2336 24673 22337

Channel Protection Storage Volume (Cpv) 18295 47652 29357


Green Infrastructure Regenerative Stormwater Conveyance

Holladay Park (RSC instead of piped drainage) Jabez Branch (receiving stream)

From piped drainage to runoff treatment and reduction

0

10

20

30

40

50

60

70

10 11 12 13 14 15 16 17 18 19 20

Dis

char

ge (c

fs)

Time (hours)

Existing Runoff versus RSC Outflow during 100-year Event

Existing

RSC Outflow

RSC Outflow minus Exfiltration

Event Existing RSC Outflow RSC Outflow Minus Exfiltration

(cfs) (cfs) (cfs) 1-yr 0.81 0 0.35 5-yr 10.1 1.87 6.06 10-yr 18.35 8.73 13.94 25-yr 33.4 22.86 29.85 100-yr 66.14 55.14 64.24



From piped drainage to runoff treatment and reduction

P has e 1-Orig inal Des ig n C urrent C os ts

P ipe L F G rading/E xcess $248,750.0015" 1453 S WM P ond $80,131.0018" 408 P ipe $23,194.0021" 48 R isers/s tructures/headwalls $30,000.0024" 517 24" P ipe $8,420.0027" 470 S andstone Weirs $14,360.0030" 52312" x14" 50 T otal $404,855.00Total L F 3469

C os tsS WM P ond 216,710.00$ R C P 592,158.75$ S WM Ac c es s R d 8,900.00$ F enc es for S WM P ond 10,700.00$

T otal 828,468.75$

L ayout $44,934.00S ediment C ontrols $21,971.00

Holladay P ark- C os t C omparis on




Reduced costs



Regenerative Stormwater Conveyance


Benefits to receiving streams – reduction of flashy flows, improved water quality and improved baseflow

Regenerative Design – Moving Beyond Sustainability

Design approach based on the value of living within the limits of available renewable resources without environmental degradation. John Lyle

In a sustainable system, lost ecological systems are not returned to existence. In a regenerative system, those lost systems can ultimately

begin "regenerating" back into existence. Not attributed

A design paradigm where human activities are deeply integrated with living systems, continuously building biological diversity, resilience

and community spirit. Not attributed


Carriage Hills Pre-restoration Anne Arundel County, Maryland


Green Infrastructure & Regenerative Design Regenerative Stormwater Conveyance

Piped Drainage & Ephemeral Gully Restoration

Watershed: Severn River Physiographic Province: Coastal Plain

Drainage Area: 11 acres

Land Use: Suburban land use, public

easement and HOA property

Project Area: 11 acres, 425 linear feet of stream (intermittent along downstream)

Slope: 10 -15%, with 22-ft incised, having an adverse effect on shallow groundwater and downstream flows



Carriage Hills Pre-restoration Stormdrain Removal & Ephemeral Gully Restoration

Piped drainage & gully to wetland complex

Green Infrastructure & Regenerative Design




Sand bed overlain with riffles and pools Green Infrastructure & Regenerative Design


Sand seepage bedding used as haul road Regenerative Stormwater Conveyance


Carriage Hills During Construction Stormdrain Removal & Ephemeral Gully Restoration

Riffle Grade Controls


Regenerative Stormwater Conveyance During Construction - built downstream up


Carriage Hills During Construction Stormdrain Removal & Ephemeral Gully Restoration


Carriage Hills Post-restoration Stormdrain Removal & Ephemeral Gully Restoration

Regenerative Stormwater Conveyance Post Restoration

Stormwater is now conveyed in a non-erosive fashion into a series of broad and flat (in cross section) and vertically undulating (in profile) riffles and pools, and converted to

groundwater through natural percolation through soils and converted into groundwater


Source: Solange Filoso, University of Maryland


Runoff Reduction Regenerative Stormwater Conveyance



Progression of Stream Restoration From Conveyance to Integrated Stream and Floodplain Techniques

Time

Func

tiona

l Val

ue

Pipe – Bury Headwater Streams

Conveyance/Concrete Channels

Integrated Stream and Floodplain Techniques

Next ?

Natural Channel Design

Rip-Rap, Gabion, Bank and Bed Treatments

Regenerative Design

Conveyance of Flows

Stream Restoration for Bay TMDLs/NPDES Credits

Next ?

Protection/Promotion of Built Environment

Aquatic Habitat Enhancement

Water Quality Improvements

Improved Channel Form

Func

tiona

l Val

ue

Time

Regenerative Design Drivers of Stream Restoration From Conveyance to Integrated Stream and Floodplain Techniques

incised groundwater

Floodplain Reconnection Approach Integrated Stream and Floodplain Techniques

Regenerative Design

Floodplain Elevation

Incised Channel Bottom

Riffle Grade Control

Regenerative Design Floodplain Reconnection Approach

Towson Run Tributary Watershed: Jones Falls, Patapsco River

Physiographic Province: Northern Piedmont Plateau

Drainage Area: 444 acres Project Area: 15 acres, 4,000 linear feet of stream

Description

Area (acres)

Percentage

Institutional 117.3 26% Low Density Residential 3.9 1%

Medium Density Residential 53.4 12% High Density Residential 171.3 39%

Commercial 50.1 11% Woods 48.4 11%

TOTAL AREA 444.4 100%

Floodplain Reconnection Approach Regenerative Design

Pre-restoration


Desired Outcomes & Goals Outcomes

Increase Canopy Recharge Groundwater Extend Base Flows Slow Flow/Velocity Wetland Hydrology

Increase Contact with Benthos Increase and Retain Carbon Inputs

Towson Run Tributary Baltimore County, Maryland

Goals establish long-term, stable

channel geometry reduce sediment yield improve water quality

capitalize on opportunities for aquatic and riparian habitat

enhancement

Effects on Downstream Hydrology & Channel Hydraulics

reduce peak discharges across a range of smaller storms

reduce depth increase roughness wetted perimeter

shear stress and velocities

Peak Discharges 10-year - 671 cfs (HydroCAD) 2-year - 330 cfs (HydroCAD) Discharge -3.6 inch runoff

event - 44 and 74 cfs


Desired Outcomes & Goals

Hydraulics – transport of water in the channel, on the floodplain and through sediments

reduce peak discharges across a range of storms reduce depth increase roughness increase wetted perimeter hydraulic radius reduce ear stress and velocities

Biology – biodiversity and the life histories of aquatic and riparian life

Velocity/depth diversity – 89% slow and shallow 11% fast and shallow, and slow and deep

Velocity/depth diversity – 67% slow and shallow 29% slow and deep 2% fast and shallow 1% fast and deep

MBSS Stream Habitat Assessment

Existing Conditions Towson Run, Baltimore County, MD

Proposed Conditions Towson Run, Baltimore County, MD

MBSS Stream Habitat Assessment

increased groundwater elevations maintenance of baseflow velocity/depth diversity

Reduce Vulnerability

Rethink Management


What are your lessons learned and thoughts on ways forward?

Documents

Innovative Strategies & Adaptive Restoration Approaches ... · Innovative Strategies & Adaptive Restoration Approaches for Tidal and Nontidal Areas Given Changing Coastal Conditions