Stream Restoration: Planning & Site Selection, Crediting and Implementation Kelly Lennon, P.E 3 Rivers W et W eather Stream Symposium June 22, 20 1 8
Agenda § Identifying Potential Stream Restoration Sites § Watershed Planning Process § Site Selection Process § Prioritizing Sites 2 § Determ ining Credit § Chesapeake Bay Expert Panel Protocols § Project Im plem entation
Identifying Potential Stream Restoration Sites
How do you start identifying potential projects? — 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 4 — 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
A W atershed Approach –Key For Success — 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 5 Practices (BMPs) to treat and im prove w ater quality.
Watershed Approach –5 Guiding Principles 1 . Place-based focus 2. Stakeholder involvem ent 3. Environm ental goals 4. Problem identification and prioritization 5. Integration of actions 6 http://www.epa.gov/owow/nps/watershed_handbook/
Elements of A Watershed Plan US EPA A through I Criteria — 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 7 — Schedule of im plem entation — Description of interim m ilestones — Developm ent of perform ance criteria — Monitoring of BMPs effectiveness
SCALE DESCRIPTION SIZE EXAMPLE Basin Large river, estuary, lake > 1,000 sq mi Chesapeake Bay systems Watershed Sub-basin State-defined, > 100 sq mi Patapsco/Back River Scale 6-digit sub-basins Watershed State-defined, 20 – 100 sq mi Jones Falls 8-digit watersheds ≤ 11 sq mi Subwatershed Specific/named streams, Western Run 3 rd order or smaller
Conducting Watershed Assessment — 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
Potential Sources for Identification of Potential Stream Restoration Sites — GIS Data Models — Aerial Im agery — Field Assessm ents — Municipal/County/State 1 0 Coordination — Watershed Reports — Citizen Com plaints
Desktop Analysis –Looking Stream Restoration Potential — Reasons to exclude — Aerial im ages potential sites based on — GIS Layers desktop analysis — Pasture land — Restoration already com plete — No stream channel show ing — 30 3d/Im paired stream s — Difficult access — Contours — Stream reach too short 1 1 — Land use — Heavily forested — Stream m ay not be perennial — Tree cover/canopy — Drains to reservoir — Stream buffers — Property ow ner denied access — Soil erodibility — Appears to be a drainage ditch (sw ale) — Parcel layers/property — Proxim ity to utilities and/or ow nership railway (CSX) — SWM pond onsite — Aerial im ages — Species of State Concern — Review of Previous Studies
Field Assessm ents –Stream Stability Assessm ents — Rapid stream assessm ents — ~1 m ile per day — Key param eters: — Fish blockages 1 2 — Bank erosion — Outfalls — Channel alterations — Flood or infrastructure concerns — Potential for habitat enhancem ent
Site Considerations that May Im pact Stream Restoration Potential — Cons — Pros — High quality forest present — Moderate to severe bank — Lim ited access erosion — Steep slopes — Lim ited riparian buffer — Minim al sedim ent and — Minim al or no utilities nutrient loading — 0 to 2 nd order stream 1 3 — Wetland creation — Local TMDLs opportunity — Site planted/in forest conservation — Utility/infrastructure constraints — 3rd order stream , too large — Reservoir dow nstream
Site Prioritization: Key Weighting Param eters — TMDL Potential — Constructability — Watershed Characteristics — Other Considerations 1 4
TMDL Potential — 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 1 5 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 1 . Streambank Erosion % Options: 75-1 0 0 % 50-74% 25-49% 0 -24% Targeting sites w ith high stream bank erosion w ill decrease large Rationale: am ounts of nutrients and sedim ent from being transported dow nstream to the Bay.
W atershed Characteristics — 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. st order system s are optim al — Stream order –1 1 6 — % 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 Category: Optim al Suboptimal Marginal Poor 1 . Stream Length >2,0 0 0 LF 1 ,50 0 to 2,0 0 0 1 ,0 0 0 to 1 ,50 0 <1 ,0 0 0 LF Options: LF LF Target longer stream lengths, which are m ore cost effective and Rationale: result in increased nutrient and sedim ent reductions.
Constructability — Access –Optim al — Forest / Tree Cover — Utilities (Visible) 1 . Access Adjacent, Minor Moderate Significant Options: — Constraints Unrestricted Constraints Constraints Constraints Access is Access is Som e steep Steep slopes, 1 7 — Proxim ity to relatively flat, relatively flat, slopes, som e heavily open, dry, open, dry, vegetation vegetated, wet State/County w ithin 1 0 0 ft of w ithin 1 0 0 - clearing, som e areas, over a public road. 50 0 ft of a w et areas, 1 ,0 0 0 ft from a Road public road, between 500 - public road, Description: m ay require 1 ,0 0 0 ft of a m ay require — Bank Erodibility special public road, special construction m ay require construction Potential road special road treatm ents. construction treatm ents. road treatm ents. Unrestricted access increases the constructability of site, reducing Rationale: overall project costs and im pacts to existing resources
Other Key Considerations — 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 1 8 — County/Watershed Group Coordination — Perm itting agencies typically favor projects that — Cost
Chesapeake Bay Expert Panel Crediting
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 20 st Order Channels • 0 & 1 • Quantifies potential sedim ent loss prevented • Converted to Annual Load reduction
Edge of Stream Interim Approved Removal Rates per Linear Foot of Qualifying Stream Restoration (lb/ft/yr) 21
Basic Qualifying Conditions for Stream Projects — Watershed Based Approach for Prioritizing and Screening — Stream reach > 1 00 lf and still actively enlarging/degrading st to 3 rd order stream s — Most located on 1 — Com prehensive approach to stream restoration including addressing long term stability of channel, banks and 22 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)
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