Stream Restoration: Planning & Site Selection, Crediting and - - PowerPoint PPT Presentation

Kelly Lennon, P.E 3 Rivers W et W eather Stream Symposium

June 22, 20 1 8

Stream Restoration: Planning & Site Selection, Crediting and Implementation

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§ Identifying Potential Stream Restoration Sites

§ Watershed Planning Process § Site Selection Process

§ Prioritizing Sites § Determ ining Credit

§ Chesapeake Bay Expert Panel Protocols

§ Project Im plem entation

Agenda

Identifying Potential Stream Restoration Sites

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— Review existing w atershed plans / PRPs

— Start by review ing existing data — Determ ine what data is available, particularly related to stream stability and riparian buffers — If stream stability assessm ents have not been com pleted, start with GIS desktop analyses to identify stream segm ents with highest potential

— Develop new w atershed plans

— Look for partners — Watersheds do not follow m unicipal boundaries — Co-jurisdictional watershed plans will be m ost beneficial for im proving w ater quality

— Review citizen/agency com plaints

How do you start identifying potential projects?

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— Hydrologically defined & geographically focused — Involves all stakeholders — Strategically addresses priority w ater resource goals — Involves assessm ent and prioritization of area’s w ater quality concerns defined by w atersheds — Design and Im plem entation of Best Managem ent Practices (BMPs) to treat and im prove w ater quality.

A W atershed Approach –Key For Success

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1 . Place-based focus

• 2. Stakeholder involvem ent
• 3. Environm ental goals
• 4. Problem identification and prioritization
• 5. Integration of actions

Watershed Approach –5 Guiding Principles

http://www.epa.gov/owow/nps/watershed_handbook/

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— Identification of the causes and sources of pollution — Estim ates of pollutant load reductions of proposed BMPs — Description of the BMPs — Estim ates of technical and financial assistance needs — Public outreach & participation — Schedule of im plem entation — Description of interim m ilestones — Developm ent of perform ance criteria — Monitoring of BMPs effectiveness

Elements of A Watershed Plan US EPA A through I Criteria

Watershed Scale

SCALE DESCRIPTION SIZE EXAMPLE

Basin Large river, estuary, lake systems > 1,000 sq mi Chesapeake Bay Sub-basin State-defined, 6-digit sub-basins > 100 sq mi Patapsco/Back River Watershed State-defined, 8-digit watersheds 20 – 100 sq mi Jones Falls Subwatershed Specific/named streams, 3rd order or smaller ≤ 11 sq mi Western Run

— Desktop analysis; rapid assessm ent and detailed field evaluations; — Upland assessm ents;

— Includes stream stability, neighborhood, pervious area and institutional assessm ents

— Storm w ater hot spots; — Natural resources inventories; — Pollutant loading estim ation –m odeling, m onitoring and TMDL baselining

Conducting Watershed Assessment

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Potential Sources for Identification of Potential Stream Restoration Sites

— GIS Data Models — Aerial Im agery — Field Assessm ents — Municipal/County/State Coordination — Watershed Reports — Citizen Com plaints

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Desktop Analysis –Looking Stream Restoration Potential

— Aerial im ages — GIS Layers

— Pasture land — 30 3d/Im paired stream s — Contours — Land use — Tree cover/canopy — Stream buffers — Soil erodibility — Parcel layers/property

• w nership

— Aerial im ages — Species of State Concern

— Review of Previous Studies

— Reasons to exclude potential sites based on desktop analysis

— Restoration already com plete — No stream channel show ing — Difficult access — Stream reach too short — Heavily forested — Stream m ay not be perennial — Drains to reservoir — Property ow ner denied access — Appears to be a drainage ditch (sw ale) — Proxim ity to utilities and/or railway (CSX) — SWM pond onsite

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Field Assessm ents –Stream Stability Assessm ents

— Rapid stream assessm ents

— ~1 m ile per day

— Key param eters:

— Fish blockages — Bank erosion — Outfalls — Channel alterations — Flood or infrastructure concerns — Potential for habitat enhancem ent

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Site Considerations that May Im pact Stream Restoration Potential

— Pros

— Moderate to severe bank erosion — Lim ited riparian buffer — Minim al or no utilities — 0 to 2nd order stream — Local TMDLs

— Cons

— High quality forest present — Lim ited access — Steep slopes — Minim al sedim ent and nutrient loading — Wetland creation

• pportunity

— Site planted/in forest conservation — Utility/infrastructure constraints — 3rd order stream , too large — Reservoir dow nstream

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— TMDL Potential — Constructability — Watershed Characteristics — Other Considerations

Site Prioritization: Key Weighting Param eters

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— Bank Erodibility Potential –Are there active headcuts or high potential for new headcut m igration? High channel incision? — Stream Bank Erosion Potential Percentage –Higher percentage of bank erosion provides greatest pollutant

• reductions. Need to look at both banks.

— Sediment Storage / Nutrient Treatment Potential – includes treatm ent of upstream sources, floodplain storage and/or nutrient treatm ent potential — Potential to incorporate other BMP strategies – strategies could include reforestation, w etland creation, trash rem oval, outfall restoration, upland BMPs

TMDL Potential

1 . Streambank Erosion % Options: 75-1 0 0 % 50-74% 25-49% 0 -24% Rationale: Targeting sites w ith high stream bank erosion w ill decrease large am ounts of nutrients and sedim ent from being transported dow nstream to the Bay.

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— Stream Length (LF) –longer stream lengths are typically m ore cost effective and result in increased nutrient/sedim ent reductions — Drainage area –sm aller drainage areas (< 1 square m ile) have higher probability for success. — Stream order –1

st order system s are optim al

— % Impervious –optim al is < 1 0 % im pervious, how ever m any urban system s fall in suboptim al category of 1 0 -29% — Biologic Uplift –look for stream s that have potential for biologic uplift or habitat im provem ents in addition to stabilization

W atershed Characteristics

Category: Optim al Suboptimal Marginal Poor 1 . Stream Length Options: >2,0 0 0 LF 1 ,50 0 to 2,0 0 0 LF 1 ,0 0 0 to 1 ,50 0 LF <1 ,0 0 0 LF Rationale: Target longer stream lengths, which are m ore cost effective and result in increased nutrient and sedim ent reductions.

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— Access –Optim al — Forest / Tree Cover — Utilities (Visible) — Constraints — Proxim ity to State/County Road — Bank Erodibility Potential

Constructability

1 . Access Options: Adjacent, Unrestricted Minor Constraints Moderate Constraints Significant Constraints Description: Access is relatively flat,

• pen, dry,

w ithin 1 0 0 ft of a public road. Access is relatively flat,

• pen, dry,

w ithin 1 0 0 - 50 0 ft of a public road, m ay require special construction road treatm ents. Som e steep slopes, som e vegetation clearing, som e w et areas, between 500 - 1 ,0 0 0 ft of a public road, m ay require special construction road treatm ents. Steep slopes, heavily vegetated, wet areas, over 1 ,0 0 0 ft from a public road, m ay require special construction road treatm ents. Rationale: Unrestricted access increases the constructability of site, reducing

• verall project costs and im pacts to existing resources

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— Property Ow nership

— Working on public land is typically easier than pursuing private properties — Agencies need to decide if they can work on private property and if they are w illing to pay for easem ents/access — Higher num ber of property ow ners typically increases the am ount of tim e in the planning and design process

— County/Watershed Group Coordination

— Perm itting agencies typically favor projects that

— Cost

Other Key Considerations

Chesapeake Bay Expert Panel Crediting

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Expert Panel Stream Restoration Crediting Opportunities

Protocol # 5 –Alternate Headw ater and Outfall Channel Protocol, is currently under review by the Urban Storm w ater Work Group

• 0 & 1

st Order Channels

• Quantifies potential

sedim ent loss prevented

• Converted to Annual

Load reduction

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Edge of Stream Interim Approved Removal Rates per Linear Foot of Qualifying Stream Restoration (lb/ft/yr)

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— Watershed Based Approach for Prioritizing and Screening — Stream reach > 1 00 lf and still actively enlarging/degrading — Most located on 1

st to 3rd order stream s

— Com prehensive approach to stream restoration including addressing long term stability of channel, banks and floodplain — Special consideration given to projects designed to reconnect channel w ith floodplain — Project not designed solely to protect public infrastructure by bank arm ouring or riprap (these do not qualify)

Basic Qualifying Conditions for Stream Projects

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— Com ply w ith all state and federal perm itting requirem ents including 40 4 and 40 1 perm its — May require pre- and post-construction m onitoring — Project m ust include one or m ore of the follow ing: — Before credits are granted, projects w ill need to m eet post-construction m onitoring requirem ents, exhibit successful vegetative establishm ent and have undergone initial project m aintenance.

Environmental Considerations

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Protocol 1 : Credit for Prevented Sediment during Storm Flow

— “Protocol provides an annual m ass nutrient credit and sedim ent reduction credit for qualifying stream restoration practices that prevent channel or bank erosion that w ould

• therw ise be delivered

dow nstream from an actively enlarging or incising urban stream ” — Most com m only used protocol for stream restoration projects

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Protocol 2: Credit for Instream and Riparian Nutrient Processing during Baseflow

— “Protocol provides an annual m ass nitrogen reduction credit for qualifying projects that include design features to prom ote denitrification during base flow ” — Nitrogen rem oval credit

• nly

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Protocol 3: Credit for Floodplain Reconnection Volum e

— “Protocol provides an annual m ass and nutrient credit for qualifying projects that reconnect stream channels to their floodplain over a w ide range of storm events” — Although a goal of m any stream restoration projects, the protocol does not typically yield high credit am ounts. — Therefore, not frequently used. — Research currently being conducted to im prove quantification of credit that is observed in practice

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— “Protocol provides an annual nutrient and sedim ent reduction rate for the contributing drainage area to a qualifying dry channel RSC project” — Works w ell for outfall and headw ater channels — May have difficulty perm itting in perennial stream s

Protocol 4: Credit for Dry Channel RSC as an Upland Storm water Retrofit

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Protocol 5: Alternate Headwater and Outfall Channel Protocol –CURRENTLY UNDER REVIEW

— Protocol provides an annual nutrient and sedim ent reduction rate based on the difference betw een actual site conditions and a stable equilibrium condition — Developed by the Maryland Departm ent

• f Transportation’s

State H ighw ay Adm inistration — Alternate to Protocol 1 — Applies to headw ater channels w here vertical incision is a dom inant m echanism for erosion

• f system

— Credit is for prevention

• f future sedim ent loss,

not loss experienced to date

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1 . Estim ate stream sedim ent erosion rates and annual sedim ent loadings

a) Monitoring –cross sections, bank pins, repeat topographic surveys b) BANCS m ethod –involves assessm ent of BEHIs and Near Bank Shear stress c) Alternative m odeling approach – BSTEM (Bank Stability and Toe Erosion Model developed by USDA- ARS)

• 2. Convert erosion rates to nitrogen

and phosphorus loadings

• 3. Estim ate stream restoration

efficiency

a) Typically use 50 % efficient unless m onitoring data show s otherwise

Protocol 1 , Sediment Prevention: Three Step Process

Above Com putation requires Bulk Density sam ples –site specific Recom m end site specific nitrogen/phosphorus sam ples

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Protocol 2, Hyporheic Zone:

1 . Determ ine the total post construction stream length that has been reconnected using a bank height ratio of 1 .0 or less

• 2. Determ ine the

dim ensions of the hyporeic box

• 3. Multiply hyporeic box

m ass by the unit denitrification rate

• 4. Check to m ake sure

w atershed cap is not exceeded (40 % cap)

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Protocol 3, Floodplain Reconnection:

1 . Estim ate the floodplain connection volum e

• 2. Estim ate the

nitrogen/phosphorus rem oval rate attributable to floodplain reconnection

• 3. Com pute annual N, P

and TSS loads

• 4. Multiple pollutant load

by the project rem oval rate to define the reduction credit — Typically provides sm all credit values — MDOT SHA not routinely com puting for projects since results are so sm all proportionately to Protocol 1 and 2

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— Maxim um recom m ended duration for rem oval credits is 5 years (MD requires triennial verification of alternate BMPs)

— Typically have 1 year to correct any deficiencies found during inspections or need to reduce claim ed credit

— Credit can be renew ed indefinitely based on field perform ance that project is operating as designed — Initial verification of perform ance: typically provided by designer, inspector or state perm it authority — Restoration reporting required to appropriate state agency

Duration of Stream Restoration Rem oval Credit

Implem enting Stream Restoration Projects

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— Planning Process

— 6 to 12 m onths

— Design Process (for Traditional Design Bid Build Projects)

— 18 to 24 m onths — Can be longer if com plex right of w ay and/or land use

— Construction Process

— Account for your agency’s procurem ent tim efram e — Once contractor receives NTP

—Tim e for m aterials and other m unicipal approvals, access road set up (1 to 3 m onths) —In stream construction w indow (assum e up to 20 0 lf of instream w ork per w eek, new contractors m ay be m uch slow er) —Last phase is planting and site clean up (1 to 3 m onths)

Sample Project Implementation Timelines

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Property Access –Critical Path Item !

— Right of W ay Acquisition

— Easem ents — Purchase in Fee

— Pros

— Provides protection of site in perpetuity — Restricts property ow ners ability to use site

— Cons

— Often requires paym ent to property owner — Adds tim e to design process

— Right of Entry

— Tem porary access for construction of project

— Pros

— Easier to obtain — Low er or no fees

— Cons

— Property owner still ow ns parcel — No restrictions about future use and/or developm ent

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— Account for your Agency’s procurem ent tim efram e — Once Contractor Receives NTP — Consider any tim e of year restrictions for instream w ork

— If these occur during your construction w indow , allow extra tim e for contractor

— Consider sensitive habitat/constraints — Construction Process

— Initial Setup –m aterial approvals, site inspections/walk throughs, access road set up (1 to 3 m onths) — Instream Construction –varies due to com plexity of job and experience of contractor (~20 0 lf of instream w ork per w eek on average) — Planting and site cleanup/acceptance (1 to 3 m onths)

Sample Project Implementation - Construction

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— Im portant to have ow ner representative fam iliar w ith the stream restoration design on-site during construction

— Ideally stream restoration designer w ho designed project — Do not need full-tim e, recom m end 2-3 days/week on average — Only during the instream w ork period — This is in addition to typical construction inspection staff who m anage day to day activities

— Consider requiring contractor to have their ow n stream restoration specialist on-site if you’re unable to prequalify contractors — Prepare as-built draw ings or at least m arked up plan set to docum ent any field changes

Construction Phase

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Alternate Delivery Techniques

— Design Build

— Shifts risks to contractor — Allow s for innovation in design, particularly in challenging locations — Provide potential bidders w ith sites — Best value

— Full Delivery

— Offer provides com plete range of services — Identify sites — Obtain perm its — Secure Right of Way — Conduct m onitoring — Turn over to Agency at com pletion of m onitoring phase — Can be used for stream s, w etlands and reforestation

Questions?

Kelly Lennon, PE Kelly.Lennon@w sp.com (410 )-385-4162