Justin Lennon, PE 3 Rivers Wet W eather Stream Sem inar June 22, - - PowerPoint PPT Presentation

Justin Lennon, PE 3 Rivers Wet W eather Stream Sem inar June 22, 20 18

— WSP Water & Environm ent

— Baltim ore, MD

— National Technical Leader

— Stream & Ecosystem Restoration — River and Bridge H ydraulics — Sustainability & Clim ate Change

— 1 6-Years of experience — Over 20 m iles of stream restoration design

—Maryland, Delaw are, New York, Virginia, Pennsylvania, North Carolina, Florida, Washington, and Haw aii

— Over $1 2 m illion of restoration designs under construction in 20 1 8

Justin Lennon, PE

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Understanding streams

— What is a stable channel?

— Sustainability — Sedim ent balance — Floodplain connectivity

Source: Rosgen, D. (1 996) Applied River Morphology, Wildland Hydrology.

Stream Classification

— Most w idely used system for defining stream condition and function — Defines a range of stable and unstable stream types — Bankfull based classification system

— Bankfull discharge ~ channel form ing flow

— Differentiates stream types based upon geom orphic characteristics

— Bankfull w idth, depth, entrenchm ent, sinuosity, and slope

Source: Rosgen, D. (1 996) Applied River Morphology, Wildland Hydrology.

Stream impairm ent and evolution

— What happens w hen a channel destabilizes?

— Schum m evolution m odel (1984)

— Loss of bed level control

— Incision / entrenchm ent

— Widening

— Bank erosion & m ass w asting — General w idening versus m eandering

— Quazi-equilibrium

Source: Rosgen, D. (2006) Watershed Assessm ent

• f River Stability and Sedim ent Supply (WARSSS),

Wildland Hydrology

.

Rosgen Stream Evolution Models

Source: Rosgen, D. (20 0 6) Watershed Assessm ent of River Stability and Sedim ent Supply (WARSSS), Wildland Hydrology .

W hy are our stream s im paired?

— Changing hydrology

— Developm ent im pacts

• n stream flow s

— Loss of balance between sedim ent m obility and Channel form

— Man-m ade alteration

— Straightening — Floodplain fill — Levees

— Legacy sedim ent

— Colonial era m ill dam s

Western Run, Baltim ore, MD Im age Source: Google Earth

Pre-Industrial Mill Dams

— Research pioneered by Merritts and Walter (F&M College) — ~1 ,70 0 m ill dam s by 1 840

— Allegheny, Beaver, Butler, Westm oreland, Fayette, Greene, and Washington Counties

Density of w ater-pow ered m ill in eastern U.S. by 1 840 . Source: Walter, R. and Merritts, D. (20 08) “Natural Stream s and the Legacy of Water-Pow ered Mills”, Science

Mill Dam influence on River Valleys

Left: Typical m ill dam w ith sedim entation patterns. Low er: Lancaster County m ill dam location m ap (1 840 ). Source: Walter, R. and Merritts, D. (20 0 8) “Natural Stream s and the Legacy of Water-Powered Mills”, Science

What happened to the m ill dam s?

Upper: Profile of Little Conestoga Creek and West Branch w ith Mill Dam locations. Lower: Conceptual m odel of legacy sedim ent stratified stream . Source: Walter, R. and Merritts, D. (20 0 8) “Natural Stream s and the Legacy of Water- Pow ered Mills”, Science

Legacy Sediment Stream Valleys

— Stabilization

— broadly defined as any activity targeted at protection / hardening

• f stream banks / bed

— Restoration

— stream construction activity targeted at achieving one or m ore levels of functional uplift

W hat are our options?

Functional uplift

— Stream function pyram id — Developed by RiverMechanics and USFWS — Basis for defining functional uplift

Source: Harm an, W., Starr, R. et al (20 1 2) “A Function-based Fram ew ork for Stream Assessm ent and Restoration Projects”, US EPA

Hydrologic Uplift

— Processes that transport w ater from the w atershed to the channel — Base of the pyram id as it strongly effects higher level functions — Without surface flow there w ould be no aquatic ecosystem

Param eter Channel-form ing discharges Rainfall/Runoff relationship Flood frequency Flow duration

Hydraulic Uplift

— Transport of w ater in the channel, on the floodplain and through the ground — Supported by hydrologic function — Closely related to geom orphologic functions

Parameter Metric Floodplain connectivity Bank height ratio Entrenchm ent ratio Flow dynam ics Stream velocity Shear stress Groundw ater / surface w ater interchange GW level Hyporheic interaction

Geom orphic Uplift

Param eter Metric Sedim ent Com petency Mobility of bedload and riffle arm or Sedim ent Transport Capacity Transport supply versus capacity Bank Migration / Lateral Stability BANCS Surveys Riparian Vegetation Buffer w idth and com position Bed Form Diversity Percentage of riffles and pools Bed Material Stability Riffle arm or stability

— The transport of sedim ent to create and m aintain diverse bed form s — Dynam ic equilibrium — Direct support of upper level functions

— Habitat diversity — Creation and transport of w ater quality contam inants

Physio-chem ical Uplift

Param eter Metric Water Quality Tem perature, DO, pH, Turbidity Nutrients TN, TP Organic Carbon

— Water quality — Designs targeted at Level 3 –geom orphology in order to provide Level 4 uplift

Biological Uplift

Param eter Microbial Com m unities Macrophyte Com m unities Benthic Macroinvertebrate Com m unities Fish Com m unities Landscape Connectivity

— Dependent on all underlying functions

— Im pairm ent at any level w ill im pair Level 5

— Biodiversity of aquatic and riparian organism s

— Natural Channel Design — Valley Restoration / Legacy Sedim ent Design — Regenerative Storm w ater Conveyance (RSC) — Hybrid Design Approaches

Stream Restoration Design m ethods

— Pioneered by Dave Rosgen — Bankfull discharge based design technique — Reference reach / natural analog based design

— Channel sizing based on bankfull scaling of reference reach

— Reference reach identified as an undisturbed naturally sustainable system — Sedim ent transport evaluations based upon non- dim ensionalized curves

Natural Channel Design

— Pros:

— Widely accepted / perm ittable m ethodology — Track record of successful projects across the Country

— Cons:

— Difficulty in identifying appropriate reference reach — Methodology is too focused on a singular discharge — Methodology is too cook-book, m ay not be w ell understood by practitioners — May not properly address the source of im pairm ent — Degree of riparian root zone reconnection is m ore lim ited than

• ther options

Natural Channel Design

— Method pioneered based upon research and observation into the role of colonial era developm ent

• n valley landform s and attendant

stream interaction — Mill dam s, legacy sedim ents and stream evolution — Design approach generally involves excavation and rem oval

• f legacy sedim ents from valley

bottom — Channel sizing target is << bankfull — Channel sizing largely based upon threshold transport of historic gravels

Valley Restoration / Legacy Sediment Design

— Pros:

— Addressed the source of im pairm ent — Greatly decreases in-channel velocity and erosive stresses — Highest degree of phreatic zone connection — Highest degree of floodplain connection

— Cons:

— Very high per LF project cost — May have significant natural resource im pacts — May have bedload transport lim itations in high yield system s

Legacy Sediment Design

Im age source: w ww .landstudies.com

— Coastal plain outfalls or regenerative step pool storm conveyance — Developed in Anne Arundle County, MD — Channel and pool sizing driven to capture up to the 1 0 -year flow in pool areas for infiltration — Sandfilter or bio m edia sub-base along channel

Regenerative Storm water Conveyance

Source: Anne Arundel County (20 1 2) “Design Guidelines for Step Pool Storm Conveyance”.

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— Pros

— Hydrologic function uplift — Water quality treatm ent — Can w ork w ith im paired landscape

— Cons

— Lim ited applicability — Space lim itations m ay lim it treatm ent effectiveness — Specialized construction m aterials

—Sandstone

Regenerative Stormwater Conveyance

Im age source: Anne Arundel County (20 1 2) “Design Guidelines for Step Pool Storm Conveyance”.

— Borrow concepts from other m ethodologies to adapt to context of any situation — Generally m ore heavily reliant on sedim ent transport role in the design of the channel — Frequently sub-bankfull design, but not exclusively so — Design typically considers a w ide range of flow conditions

Hybrid Design Approaches

— Developed by Dave Rosgen (1 997) — Sim ple descriptive classification system for restoration approaches — Priority levels 1 through 4

Priority levels of Restoration

Im age Source: North Carolina Stream Restoration Institute; Stream Restoration –A Natural Channel Design Handbook

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Priority 1

— Construct channel to reconnect to the upper terrace floodplain — Preserves natural resources — Floodplain Im pacts

— CLOMR?

— Net fill

Peachwood Park Tributary

— BEFORE — AFTER

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Priority 2 & 3

— Balanced construction, raising of channel bed / grading of in-set floodplain benches — Potential for cut / fill balance

— Not likely though

— Priority 2 vs 3 — Balance or im prove floodplain m anagem ent

Foster Branch

— Before — After

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Priority 4

— Hardening of stream banks in situ — Stream stabilization — No reconnection of riparian root zone — High m aterial costs — Highest expected m aintenance needs

Western Run

— Im bricated Rock Wall — Constructed Riffle & Rock Sill

Design Process

Watershed assessm ent / Site Selection Visual assessm ent / project lim its and goals Geom orphic survey & natural resources Classification & characterization Horizontal and vertical alignm ent Channel design / sizing Sedim ent transport evaluation Hydraulic evaluation Site grading In-stream structure designs Material selection Project delivery

Dead Run Stream Restoration Catonsville, MD

— Baltim ore County Dept. Environm ental Protection and Sustainability — 4,70 0 lf of 1

st and 2nd order stream channel

— Included an off-line wet pond SWM facility

— Channel system ically im paired

— Entrenched F Type channel

— Priority 2 / 3 Restoration Design — Hybrid design approach — $2.2 Million Low Bid — Environm ental Quality Resources LLC — 6 m onth in-stream construction period

Dead Run Stream Restoration

Construction Com pleted

• Dec. 201

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May 27, 20 1 8 –3pm to 6pm

Ellicott City, MD Left Im age Source: Washington Post Right Source: National Weather Service

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Dead Run - May 27, 20 1 8

— Gauge failed at 3:30 pm — Gauge is located 1 ,50 0 l.f. dow nstream of project area

Dead Run May 28, 20 1 8

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Not perfect, but not bad…

— Rosgen - Wildland Hydrology

— Short Courses, Applied River Morphology, and Watershed Assessm ent of River Stability and Sedim ent Supply (WARSSS)

— NRCS Stream Restoration Handbook (NEH 654) — Regenerative Step Pool Conveyance –Design Guidelines

— Anne Arundel County, MD

— A Function-based Fram ew ork for Stream Assessm ent & Restoration Projects (EPA 843-K-1 2-0 0 6)

Design Resources

QUESTIONS?

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Justin Lennon, PE Justin.Lennon@w sp.com (410 )-752-9632