wetlands test

What is a wetland?

land that is saturated with water, either permanently or seasonally, such that it takes on the characteristics of a distinct ecosystem

Cowardin wetland definition

Lands transitional between terrestrial and aquatic systems where the water table is usually at or near surface or the land is covered by shallow water.

What is riverine?

‘related to or situated on a river or riverbank; riparian

Three part evaluation standard is

Vegetation (hydrophytes), soil (undrained hydric soil), hydrology (water during growing season)

Marine and Estuarine sytstems

mean low low water

Riverine and lacustrine =

2 m below low water

Cowardin classifications systems

Marine, estuarine, riverine, lacustrine, palustrine

Marine

saline > 30 ppt, go from continental shelf to open ocean terrestrial shores

Estuarine

mixed salinity down to 0.5 ppt, lying within enclosure of river, bays, and sounds up to terrestrial uplands

Riverine

< 0.5 ppt, lying within channel banks, usually has some flowing water

Lacustrine

< 0.5 ppt, lying within topographic depression or dammed channel, not more than 30% cover of vegetation, must be > 8 ha in size

Palustrine

< 0.5 ppt areas with vegetation, but tidal; also includes non-vegetated areas with no active shorelines, water depth must be < 2 m, and area must be < 8 ha; typically used to include anything that does not fit in the other systems

The value of wetlands?

habitat for migratory birds, 95% fish use marshes, richest carbon stores

Why are we losing wetlands?

Dredge and fill, development, agriculture, Channelization, diking, damming, alteration of hydrological flow Shoreline protection, removal of vegetation, mowing, grooming, Dropping/raising water level in soil, Relative sea level rise

Rivers and Harbors Act 1899

First major US environmental law; no dumping or unauthorized alteration of “navigable waters” – regulated by United States Army Corps of Engineers

Clean Water Act - Section 404

Can not dredge or fill a wetland. Need permit. No net loss of wetlands - lose an acre build an acre - mitigation

US vs. Riverside Bayview Homes

Adjacent wetlands included, with some hydrological connection to navigable waters

Rapanos vs. United States

Isolated wetlands not included, must have a “significant nexus” to navigable water; actually a split decision, no definite guidance for regulations to USACE 

Sackett vs. EPA

Limited definition of jurisdictional wetlands to those with continuous connection to navigable water; intermittent connections not included

The three types of wetland laws?

1. Statutory law (US Congress, e.g. CWA)

2. Regulatory law (federal agency, published in the Federal Register, e.g. major procedures to implement statutory law)

3. Administrative law (rules created within federal agency, e.g. published manuals)

The USACE permit system is

a way to achieve ‘no net loss’ objective of Section 404

regulated by USACE

sets up compensatory mitigation req

Preference of permit system

1 avoid 2 minimize 3 mitigate

Types of mitigation

-Off-site mitigation or on-site

-Simple or in-advance mitigation banking

-Self banking or using In-Lieu Fee (ILF) program

Mitigation Banking

 organized buying and selling of wetland restoration/conservation credits

the organized buying and selling of liability and responsibility to maintain wetland function into the future

-ILF mitigation banks are now the preferred option

Benefits of mitigation banking

The wetlands are replaced/constructed by a company that is in the business of restoration

When mitigation banking you have to consider

-Proximity of restoration to altered site is important

-Type of restoration is important (In-kind vs. Out-of-kind)

-Mitigation ratio: 1:1? 1:20? Are constructed wetlands as good

as natural wetlands? What are the rules for banking?

Wetland deliniation definition

defining the boundaries of a wetland, for compensatory mitigation

What is a “jurisdictional wetland” by USACE standards?

An area that exhibits hydrophytic vegetation, hydric soils, and wetland hydrology

HGM hydrogeomorphic method is better because

it allows wetlands to be compared based on functional equivalence

HGM steps

A. Classify the wetland

B. Find a reference site wetland, to use as a target

C. Identify the functional indices that will be used

D. Assess them

Reference site

a location or piece of land that is used as a benchmark to gauge the desired outcome of your restoration project, a model

Monitoring

Measuring and assessing the restoration project as it progresses over time

Types of monitoring

-pre-construction monitoring

-post-construction monitoring

-major grousing that it is an afterthought

Wetland hydrology

inundated either permanently, or semi-permanently and the soil is saturated at some time during the growing season of the prevalent vegetation

The key hydrological feature

- water has an overriding influence on soils and vegetation due to anaerobic and reducing soil

indicators of wetland hydrology

1. Stream or tidal gauge

2. Inundation or soil saturation

3. Watermarks

4. Driftlines - water floats junk far out

5. Sediment deposits

6. Drainage patterns

7. Crab holes/crawfish

3 hydrologic pathways to get water to your wetland

Groundwater-surface flow- precipitation

much of texas is -

surface flow

How can you manage hydrology

 put water in and take it out

Hydrological Management Example:

Pterocarpus swamp forest in Humacao, Puerto Rico Problem: Pterocarpus forest dying due to salinity (canal opening and sea level rise), and lack of freshwater inflow (diking and draining)

-sugar cane plantations - land recovers - plantations abandoned and now lagoons - channel to drain water = turned to mangrove

Hydrological management:

1. Upstream inflow

2. Canals and diversions

3. Dikes and levees

4. Draining

5. Weirs

6. Subaqueous barriers

Hydrological Restoration:

removal or modification of anthropogenic barriers to flow; typically, a very cost- efficient method

Hydric soil

 formed while saturated, flooded, or ponded during the growing season, with anaerobic microbial activity that depletes oxygen, causing reduced conditions

How does reduction happen?

1. Water saturation results in anoxia (no oxygen)

2. Anaerobic microbes that live in anoxic conditions generate their energy through a different metabolic pathway (fermentation) than aerobic microbes.

3. This pathway turns Fe3+ into Fe2+, and then Mn4+ to Mn2+, and finally S042- to H2S

4. Reduction refers to low soil redox potential, or reduction-oxidation potential (measured in mV)

5. Reduction increases plant stress by making it more difficult to acquire nutrients

indicators of hydric soil

1. Organic matter accumulation

2. Sulfur smell

3. Gleyed layers

4. Mottling or streaking

5. Concretions - small iron or magnesium masses, often generally spherical

A big problem for the restoration of wetland function:

good soil takes a long time to form. ~20-50 years to reach relatively similar carbon densities in the root zone (say around 15 cm of depth). ~1000 years or more to really be the same in the full profile.

So, how to restore and manage wetland sediments?

1. Promote vertical accretion at your site - Organic and autochthonous (by increasing plant productivity)

2. Promote (or inhibit) mineral sediment deposition by taking advantage of currents and transport patterns horizontally or from upstream

3. Get and move sediment for free when you can! - Beneficial Use’ of dredge spoil.

4. Follow the law and be a good neighbor when managing sediments – if dredging or digging, contain your sediment spoil with a boom and curtain – and, use sediment fencing or temporary diking to avoid runoff into the watershed or terrestrial areas

5. Protect the shoreline if there is wave or current erosion -Get the soil type as cohesive as possible

If the energy is substantial, protect using a living shoreline

(reef balls, shells, rock, shingle/old roots, geotubes, hard structures if needed)

Don’t worry about the vegetation for wave erosion

worry about the soils

Hydrophytic vegetation:

prevalent vegetation is composed of macrophytes that are adapted to inundation or saturation and thus anaerobic soil conditions

indicators of hydrophytic vegetation

A. Plant species

B. Morphological, physiological, or reproductive adaptations

A. Plant species

-more than 50% of dominant species are OBL, FACW, or FAC -Obligate (OBL), almost always in wetlands, > 99% of time -Facultative Wetland (FACW), usually in wetlands, > 67% of time -Facultative (FAC), about equal probability of being in wetland or not -Facultative Upland (FACU), < 33% of time in wetlands -Obligate Upland (UPL), <1% of time in wetlands

B. Morphological, physiological, or reproductive adaptations

pneumataphores

buttressed trunks

shallow or adventitious roots

floating leaves

floating seeds

how to restore and manage wetland vegetation?

1. Select your target vegetation mix -often primarily based on elevation relative to water level or water table -wetland vegetation communities are typically strongly zonated based on the hydrology

2. Decide whether to plant in an organized pattern or allow ‘self-organization’ to happen? –usually a combo is used

3. Draw up the planting plan (density and locations)

4. Buy the seed or transplants, or propagate them yourself from cuttings or rhizomes -most wetland plants work using cuttings/rhizomes, don’t even need rooting agent

5. Irrigate or fertilize -these are rarely-used for wetlands

6. Remove/manage invasive species -mechanical -chemical -fire -flood them out, etc

Integrated Solutions

1. biostabilization of rivers/shoreline banks

2. ecosystems as barriers to energy

3. ecosystems to ‘engineer’ the geomorphology of landscapes

4. integration of green and civil construction materials science

The key to shorelines that are ‘alive’ is not the structures, but rather

the ecological processes