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Restoration and Creation

Wetlands Restoration andCreation:A Look at the Study, Process,and Design of Rehabilitatedand New Wetlands

Claire Tomkins, Dan Barrientos, Brandy Stewart


Introduction

I. Why restore and create wetlands?

II. Approaches to restoration and creation of wetlands

III. Criteria for measuring success“Improving the Success of Wetland Creation and Restorationwith Know-How, Time, and Self-Design”

IV. Restoring hydrologic conditions and hydrologicequivalence in wetlands“The Need to Define Hydrologic Equivalence at the LandscapeScale for Freshwater Wetland Mitigation”

Part 1.

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Introduction

V. Visiting the Everglades: a look at Florida’s southernWetlands

VI. Case Study: Kissimmee River Restoration Project

VII.“The design of ecological models for Evergladesrestoration”

VIII. Group design projects and presentations

IX. Conclusions

Part 2.


Why restore and create wetlands?• Current estimates suggest between 4 to 6 % of Earth’s landsurface is wetlands: 7 to 9 million km2

•Estimates of wetland loss: perhaps as much as 50% of originalwetlands on Earth’s surface

• Documented cases: New Zealand about 90% and the U.S. about50%

• Europe: >90% and China about 60%

• Peat harvesting in Europe, drainage for agricultural use

•U.S. Swamp Land Act of 1849, encouraging wetland drainage(transferred federal wetlands to states for draining)

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Why restore and create wetlands?

Twenty-two states have lost at least 50% of their original wetlands since the 1780s. Seven states—including California have lost over 80%.

This loss can be primarily attributed to agricultural and urban development.


Why restore and create wetlands?• To prevent further deterioration of existing wetlands and toprovide needed habitat, as we’ll see in the Everglades

• To mitigate the loss of fisheries

• To enhance water quality

• Flood control

• Coastal enhancement and protection

• Laws and regulations: U.S. “no net loss” policy

• Societal values or perhaps “existence value”

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Why restore and create wetlands?Terminology:

“Mitigation wetland:” a constructed wetland intended to replace awetland “function” lost due to development, etc.

“Replacement wetland:” more appropriate terminology for above

“Mitigation ratio:” a ratio of 2:1 indicates that 2 ha. of wetlands willbe restored or created for every 1 ha. Destroyed

“Mitigation banks:” a mitigation strategy by which wetlands areestablished prior to development in an area and “wetlands credits”can be purchased by those about to incur wetland loss, for example62 existing in Florida


Approaches to wetlands restorationand creationThe process is intricately connected to the type of wetland beingcreated or restored. Examples include the following:

• Pothole marshes in agricultural tracts where “farm ponds” arebuilt, created by flooding shallow hollows to provide drinkingwater for cows, etc.

• “Cropped wetlands” restored on farmer’s land, which servewetlands functions when crops are not being grown

• Mississippi River alluvial valley reforestation with bottomlandhardwood species, tracking basal area, although forested wetlandsare generally slower to become established

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Approaches to wetlands restorationand creationConsider the goal of the restoration project, which may be any of

the following:

1) Flood control

2) Wastewater treatment

3) Stormwater or nonpoint source pollution control

4) Ambient water quality improvement

5) Coastal restoration

6) Wildlife enhancement

7) Fisheries enhancement

8) Replacement of similar habitat

9) Research wetland Mitsch and Gosselink 669


Approaches to wetlands restorationand creationSite Selection:

• Wetland restoration is generally more feasible than wetland creation

• Take into account the surrounding land use and future plans for land use

• Undertake a detailed hydrologic study of the site (surface water, ground water,precipitation, ET, etc.)

• Find a site where natural inundation is frequent

• Inspect and characterize the soils in some detail to determine their permeability,texture, and stratigraphy

• Determine the chemistry of the soils, groundwater, surface flows, floodingstreams and rivers, and tides that may influence the site water quality

Mitsch and Gosselink 672-73

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Approaches to wetlands restorationand creationSite Selection:

• Evaluate on-site and nearby seed banks to ascertain their viability and response tohydrologic conditions

• Ascertain the availability of necessary fill material, seed, and plant stocks and access toinfrastructure (e.g. roads, electricity)

• Determine the ownership of the land and, hence, the price

• For wildlife and fisheries enhancement, determine if the wetland site is along ecologicalcorridors such a migratory flyways or spawning runs

• Assess site access

• Ensure that an adequate amount of land is available to meet the objectives

• Evaluate the position of the proposed wetland in the landscapeMitsch and Gosselink 672-73


Approaches to wetlands restorationand creationOptions for a Riverine Environment

• “Natural design” of riverine wetland, where the wetland is fedprimarily by a flooding stream of river, allows for seasonalflooding of of the river to deposit sediments and chemicals in thewetland

• The wetland design could allow for flood waters to be slowlyreleased back to the river or to be retained through use of flapgates

• Advantage of using a pump to feed the riverine wetland: a morehighly predictable environment than, say, an instream system; maynot suit every purpose or objective of wetland function

Mitsch and Gosselink 670-72

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Criteria for Measuring Success“Improving the Success of Wetland Creation and Restoration withKnow-How, Time, and Self-Design” by Mitsch et al.

What are some problems with past of current approachesto “judging wetland success?”

• “Easily measured parameters for monitoring: plant lists, animalswitnessed, and percentage vegetation” and not for instancehydrologic conditions

•No continuity to monitoring: once or twice annual visits

• Time scales: the importance of allowing, say 15-20 years,to look at “wetland success” rather than the minimal 5 yearperiod


•Criteria for MeasuringSuccess

What’s the most common method used to “monitor the progress”of mitigation or replacement wetlands?

• Observing vegetation. An oversimplified criterion fromMassachusetts: if over 75% is covered, the wetlands is billed asuccess, regardless of vegetation type (function)

Does anyone remember what a Jacard similarity coefficientis?

• JSC=C/(A+B-C)*100, where A=number of species in anexisting community, B=number of species in respectivecommunity or on species reference list, and C=number ofspecies common to A and B; if JSC=100 it indicates that bothspecies lists are the same

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•Criteria for MeasuringSuccess“Know-How”

• Wetland hydrology: the “fundamental forcing functionof wetlands”

• Distinguish between “empiricism” and science, wheretypical approaches tend to “learn as we go”

• Consider the use of models, for instance

• Common problem: “flashy” streams and a highergroundwater table, which is a critical feature of thewetland



“Give the System Time”

• Again emphasizes moving away from a 5-year time framefor monitoring and appraisal

• Example: freshwater tidal marsh in Virginia, constructed in1974-75, seemed to be a success in the first 4 years ofmonitoring, but four years later the dikes breached

• Argue that long-term success is less dependent on initialconditions

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“Give the System Time”

• Again emphasizes moving away from a 5-year time framefor monitoring and appraisal

• Example: freshwater tidal marsh in Virginia, constructed in1974-75, seemed to be a success in the first 4 years ofmonitoring, but four years later the dikes breached

• Argue that long-term success is less dependent on initialconditions



“Self-design”

What are the two design approaches Mitschidentifies (think fashion!)?

• “Designer” wetlands, in which species are introduced andcultivated (much like a large garden) vs. “self-design” wetlandsin which a host of species are introduced and left to their owndesigns

• Why self-design? What survives will more likely thrive andencourages a response to hydrologic conditions; in some cases,diversity and richness increase with age

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Restoring Hydrologic Conditionsand Hydrologic Equivalence inWetlands

“The Need to Define Hydrologic Equivalence at the LandscapeScale for Freshwater Wetland Mitigation” by Barbara L. Bedford

• Emphasis on the need for understanding of wetland hydrology(Mitsch)

What is “hydrologic equivalence,” as Bedford defines it?

“…at the scale of landscapes in terms of the kinds, numbers,relative abundances, and spatial distribution of wetlandtemplates.”



Concepts discussed in the paper:

• Landscape management policy : an approach to wetlands restorationthat recognizes that the wetland is situated in broader landscape, withwhich it interacts

• Hydrology is most important factor: “Replacement wetlands cannotbe considered equivalent to lost wetlands unless their hydrologicfeatures are equivalent”

• Templates for wetland development: emphasizes hydrogeologicsetting and differentiating properties of sites and types of wetlands

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Templates

• Climate drives the entire system (precipitation, evaporation, andtemperature)

• Topographic controls: Depressions, land slope

• Substrate: permeability and geologic characteristics

• Key hydrologic variables: water sources (%), water chemistry, spatialand temporal dynamics

•Diversity: “geological heterogeneities” effecting species and hydrology



Landscape Approach

• “Profile development:” a way of understanding hydrogeology of the areaas well as long-term hydrologic variables

• Pragmatic or spatial delineation of a “landscape” by identifyingecoregions based on soil, land-surface form, and other factors

• Goals within the region:

1) Self-maintaining wetlands in mitigation sites

2) Maintenance of biodiversity

3) Short-term vs. long-term plans re species preservation/reintroduction

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Group Design Projects

ÜJust what you have all been waiting for . . . . .Your own chance to look at a wetlandsrestoration and creation project . . .


Group Design Projects - Plan

1) Read over Part II of the scenario

2) What is required?

3) Each group will have 45 minutes to complete the“mini - project”

4) 10 minute presentation by each group

5) Wrap Up

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Group Design Projects - what toinclude?

1) Each group should choose a site for their wetland2) Perform a water balance3) Create a hydroperiod for the wetland from the information

provided and by taking vegetation into account4) Following the mathematical work please take the criteria on

the following two slides as well as any your group hasdeveloped into account in your project


Recap: Measuring Success of YourCreation or Restoration ProjectWe’ve already mentioned a few considerations for measuringsuccess (Mitsch et al.):

• What time scale and monitoring plan will you use?

• What specific factors would you use? Vegetation cover? AJacard similarity coefficient? Hydrologic monitoring?

• How will you seed and cultivate your wetland, and how doesthat choice influence its “success?”

• Pretend you have to present an evaluation to a state Board,what arguments would you present?

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Recap: Measuring Success of YourCreation or Restoration ProjectClean Water Act Section 404 (also Federal PollutionControl Act)

• A permit to dredge or fill “waters of the U.S.” isrequired

• Mitigation ratio determines the area of wetlands thatmust be constructed or restored to mitigate the loss

• Criteria for judging the wetland a success must bepresented at the outset

Have Fun!

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