Presentation on theme: "Ecological Systems Maintaining and Enhancing Natural Features and Minimizing Adverse Impacts of Infrastructure Projects Module 6 Restoring Ecological."— Presentation transcript:
1Ecological Systems Maintaining and Enhancing Natural Features and Minimizing Adverse Impacts of Infrastructure Projects Module 6 Restoring Ecological Function
2Emily Mitchell Ayers, Ph.D. The Low Impact Development Center, Inc.
3Learning Outcomes Understand the value of ecological restoration Learn to focus on restoring ecological function rather than appearanceBecome familiar with techniques employed in a variety of restoration contexts
4Ecologically-Sensitive Design Process Know where you areAvoid sensitive areasMinimize infrastructure impactsMitigate unavoidable lossesImprove ecological function where possible
5Mitigation BankingWhen damage to a wetland, stream, or aquatic resource is unavoidable, impacts may be offset by restoring or preserving an equivalent resource off-siteMitigation Banks are areas set aside to create large-scale, intact ecosystemsEPA
6Advantages of Mitigation Banking Wetlands in mitigation banks are restored prior to the destruction of existing wetlands on-site, which allows verification of equivalent functionLarger intact ecosystems are more stable than smaller, fragmented systems, and can support larger wildlife
7CaveatsMitigation banking is well-established only for wetlands; other ecosystems, especially upland ecosystems are not includedSome small wetlands, such as vernal pools, are critically important for amphibian breeding and migratory birds
8Ecologically-Sensitive Design Process Know where you areAvoid sensitive areasMinimize infrastructure impactsMitigate unavoidable lossesImprove ecological function where possible
9Basic Principles of Ecological Restoration Consult with expertsRemove barriers to ecological functionEstablish key species to jump-start self- organizationProvide connectivity to existing habitatBe patient!
10Consult with ExpertsEcological restoration is a discipline in its own rightA growing number of specialists around the country have expertise and experience with restoration projectsIncluding experts on your team can help to ensure success and avoid unintended consequences
11Remove Barriers to Ecological Function Energetic barriersAltered hydrologyMaterial barriersExcessive nutrient inputsAltered sediment deposition (too much or too little)ContaminationSpecies-specific barriersNoise, light pollution, habitat requirements, connectivity
12Install Key SpeciesUsually, this involves establishing an appropriate plant communityThe plant community provides a backbone for the ecosystem, allowing colonization by animals
13Provide Connectivity to Existing Habitat This promotes colonization by species adapted to site conditions as they disperse from adjacent habitats
14Using Succession and Self-Organization It is impossible to physically reconstruct a functioning ecosystem, as you would build a carCreating appropriate conditions, and providing as much biodiversity as possible will allow the ecosystem to self-organize
15PatienceSome ecological processes take place over very long time periods (e.g. topsoil development, peat bog formation)It may or may not be possible to hurry these processes along to meet human timetablesOnce energy and material flows are restored, ecological processes will take over, and will eventually establish a functioning, complex, ecosystem
16If you build it, they will come (provided they can get there)
17Restoring Hydrology in Streams Stream geomorphology (the size and shape of the stream bed and banks) is a direct response to the size of storm flows
19Morphological Changes Due to Urbanization Disconnection from floodplainNorthern Virginia Soil and Water Conservation District
20Incised StreamNorthern Virginia Soil and Water Conservation District
21Match Morphology to Hydrology If in-stream structure and meanders are rebuilt without addressing underlying hydrologic issues, there is a strong likelihood that restoration efforts will failRestored stream morphology must match the current energy signature
22Options to Restore Hydrology BEST OPTION: restore watershed hydrology, then rebuild in-stream physical features Unfortunately, watershed hydrology is the cumulative result of actions on multiple sites, so this is not generally possible in the context of a single infrastructure project
23Restoring Stream Hydrology ALTERNATE STRATEGY:If possible, use floodplain to detain and infiltrate stormwater runoffInstall energy dissipating structures to reduce erosive power of storm flows
24Energy Dissipating Structures Rock weirsPrevent scouringDissipate energyDirect flows away from banksNorthern Virginia Soil and Water Conservation District
25Bank StabilizationWhere flow velocities permit, banks can be stabilized with vegetationBiodegradable reinforcements can be used while vegetation becomes establishedIn highly erosive conditions, stone may be necessary
26Restoring In-stream Habitat Tree trunks with root wads can be used to slow and direct flows and provide habitatTrunks must be firmly anchored in stabilized banksBLM
27Reducing Nutrient Inputs OPTIONS:Reduce fertilizer application in watershedCapture and treat runoff close to the sourceCapture and treat runoff at the point where it is discharged to the water body (end-of- pipe)
28Removing Nutrients Close to the Source Wastewater Treatment: Tertiary treatment to remove nitrogen and phosphorusAgriculture: Use vegetated buffers between fields and surface watersStormwater: Remove nutrients using Low Impact Development BMPs such as bioretention
30Reducing Sedimentation Install erosion control structures, either in-stream or within watershedLive fascinesand coir blanketFWS
31Restoring Wetland Hydrology Wetland hydrology is all about flooding depth and frequencyThese two parameters must be correct for a wetland restoration project to be successfulFWS
32The Importance of Wetland Hydrology Wetland plants are primarily responsible for maintaining wetland structure and functionThese plants have very specific hydrologic requirementsNRCS
33Restoring Sedimentation Remove dams and levees where possibleInstall energy dissipating structures to reduce erosion and promote settlingInstall sediment diversion structuresTrucking in sediment is a short-term fix, but may fail in the long run if erosive forces and subsidence are not balanced by ongoing deposition
35Lake and Pond Restoration Lake and pond deterioration is usually a result of excess nutrient loadingIn addition to methods previously discussed, nutrients can be removed usingAlgal turf scrubbers, andFloating islands.
36Algal Turf Scrubber™ (ATS) Water is pumped down a chute seeded with filamentous algaeAlgae grows, taking up excess nutrientsAlgae is harvested periodically, preventing eutrophication related to die-offUniversity of Maryland – NEED PERMISSION
37Floating Islands Floating treatment wetlands Wetland plants are suspended on floating matsRemove excess nutrients from the water columnFloating Islands InternationalNEED PERMISSION
38NW3.4 Maintain Wetland and Surface Water Functions 3 points: Enhance one ecosystem function6 points: Enhance two ecosystem functions9 points: Enhance three ecosystem functions15 points: Enhance four ecosystem functions19 points: Restore full ecosystem function
39NW3.4 Maintain Wetland and Surface Water Functions (cont’d) Enhance hydrologic connectionsReconnect rivers to their floodplainsRestore wetland hydrologyEnhance water qualityDisconnect surface water dischargesUse BMPs to infiltrate runoffEnhance habitatRestore riffles, pools, shorelinePlant appropriate speciesEnhance sediment transportRemove dams and other impediments
40Restoring Disturbed Lands Areas connected to intact habitat will tend to regenerate following disturbanceNatural successional processes may take decadesInvasive and exotic species may need to be controlled
41Fire-Dependent Ecosystems Controlled burns can help to restore fire- dependent ecosystemsManual removal of underbrush may be an acceptable substitute where burning is infeasible, but some functions of fire are difficult to replicateSome seeds require high temperatures in order to trigger germination
42Soil RestorationSoils are an essential component of terrestrial ecosystemsSoil restoration involves:Removal of contaminantsReversing soil compactionIncreasing soil organic matterRestoring soil ecological function
43NW3.3 Restore Disturbed Soils 8 points: Restore all soils disturbed during construction in the site’s vegetated area10 points: Restore all soils disturbed as a result of previous development
44NW3.3 Restore Disturbed Soils (cont’d) Prior to development, topsoil should be removed and stockpiledAfter development, topsoil is replaced on unpaved disturbed areas, and quickly vegetated to minimize erosionRestoring soils disturbed as a result of previous development may require amending and aerating soils
46Bioremediation Use of bacteria to break down or transform contaminants Involves creation of environmental conditions conducive to bacterial functionMay require bioaugmentation with specialized bacteria or catalystsLawrence Berkeley National Laboratory
47Phytoremediation Use of plants to bind or break down contaminants Hyperaccumulators translocate metals from soil into plant tissues, which can be harvestedHybrid poplars detoxify organic solventsNIH
48Reducing Light Pollution Limit nighttime lighting to only what is necessary for safetyUse lights that cast light downward rather than upwardNPS
49Reducing Noise Pollution Plant trees to dampen noiseConstruct noise barriers around highwaysFHWA
50Discussion QuestionsWhat issues might you encounter if you attempted to restore an abandoned farm to its predevelopment condition?
51Discussion QuestionsHow is it possible to restore streams, lakes, and wetlands if you have no control over what is happening in the watershed?
52Review Mitigate unavoidable ecosystem losses Restore ecological function wherever possibleConsult with expertsRemove barriers to ecological functionEstablish key species to jump-start self-organizationProvide connectivity to existing habitatBe patient!
53Recommended Resources Society of Wetland Scientists. SWS Position Paper: Wetland Mitigation Banking.Society for Ecological Restoration, SER Primer on Ecological Restoration.NRCS Stream Restoration Portal.NRCS, Engineering Field Handbook, Chapter 18: Soil Bioengineering for Upland Slope Protection and Erosion Reduction ftp://ftp-nhq.sc.egov.usda.gov/NHQ/pub/outgoing/jbernard/CED- Directives/efh/EFH-Ch18.pdfUSEPA. Principles for the Ecological Restoration of Aquatic Resources.