Constructed or Natural: What is a More Suitable

Wetland?

Phillip K. Adasczik

Geography Department,

The Pennsylvania State University, State College, PA 16801, USA

Abstract

A field experiment was performed to evaluate the similarities and or differences between two local

wetlands; Shaver’s Creek (a natural wetland) and Emerick wetland (a constructed wetland).

Wetlands can be defined as areas where the ground is inundated or saturated throughout a

majority of the year. They are normally classified through the observation of hydrology, vegetation,

and soil presence. Wetlands are of extreme importance to environments as they control water flow,

erosion, flooding, and offer shelter for various plant and animal species. Wetlands filter out

abundances’ of sediments and or nutrients through filtration thus improving water quality at a

much earlier cycle stage. A major influence of wetlands are simply other flows of water that reach

these wetlands, however the influence in alteration from human development; such as urban and

agricultural means has gradually redefined these wetlands. For both the natural and constructed

wetland locations, microtopography was recorded by utilizing a tripod transit and stadia rod. This

allotted for the reading of elevations in the study areas. The differentiation between the two study

areas were implementations of surface depressions. The natural wetland had depressions, whereas

the constructed did not.

Introduction

What exactly is a wetland? The US Fish and Wildlife Service (USFWS) states wetlands are “Lands

transitional between terrestrial and aquatic systems where the water table is usually at or near the

surface or the land is covered by shallow water. A wetland’s classification must have one or more of

three attributes: 1) at least periodically, the land supports predominantly hydrophytes; 2) the

substrate is predominantly un-drained hydric soil; 3)the substrate is non-soil and is saturated with

water or covered by shallow water at some time during the growing season of the year” (Rocco,

2013). The US Army Corps of engineers (USCOE) defines a wetland as “Areas that are inundated or

saturated by surface or ground water at a frequency and duration sufficient to support, and that

under normal circumstances do support, a prevalence of vegetation typically adapted for life in

saturated soil conditions” (Rocco, 2013).

A wetland is simply classified by its present characteristics in regards to hydrology, vegetation

and soil. Hydrology is the presence of water within an area, thus determining the driving factors

that compose a wetland. In the instance that water is of absence, then hydrophytes would struggle

to grow or establish within the wetland. This would also result in the absence of reduced soils

(Rocco, 2013)

There are various wetland types and these types are classified in correlation to how water is

delivered to the wetland. The saturation rate and frequency of hydrological processes are all taken

into consideration, hence dictating the hydrophyte and soil establishment in these areas (Rocco,

2013). Ultimately, wetlands are dependent upon the hydrology factors. In Pennsylvania, the

different wetland types are as follows: Headwater Floodplain, Mainstream Floodplain, Isolated

Depression, Riparian Depression, Fringing, and Slope wetlands. Just like wetlands in other regions,

Pennsylvania’s wetlands are dependent on the geographic structure of the land. The topography

also has an effect on the micro topography in wetlands, which influences the variance in elevation.

Variance in a wetland can range from one centimeter to one meter and the change in variance

implements micro topography heterogeneity and floristic diversity (Vivian-Smith 1997). Micro

topographic heterogeneity is considered to be a major determinant and its coexistence is thought to

be facilitated in heterogeneous environments due to interspecific differences in habitat preference.

Micro topographic heterogeneity is a major factor structuring natural freshwater wetland

communities and is thought to influence diversity (Vivian-Smith 1997).

Wetland vegetation is highly constructed of plants that are adaptive and tolerant to both inundated

and saturated soils. The vegetation dynamics and species diversity of many plant communities are

thought to be strongly influenced by soil nutrient heterogeneity. Microtopographic variation has

been strongly correlated with plant distribution and performance, for individual plant species and

for plant communities in wetlands (Vivian-Smith 1997). Explanations for such patterns include

deferential seed accumulation variation in species germination requirements; and differences in

growth and mortality at different microtopographic positions (Vivian-Smith 1997). These adaptive

and tolerant plants to inundated and saturated soils are known as hydrophytes (Rocco 2013).

Hydrophytes exhibit morphological, physiological, and reproductive adaptations. Examples of these

would include exposed roots on the surface, tree trunks, and viable seeds. To be classified as a

wetland, an area must be dominated by these hydrophytes; which would contain a minimum of

50% facultative wetland (FACW), and Obligate wetland (OBL) (Rocco 2013).

The last factor in wetland classification is soil. Soils that are established with wetlands are normally

hydric soils. Hydric soils are substrates providing reducing conditions as a result of temporary or

permanent inundation or saturation. Essentially, hydric is associated with the presence or living or

deceased organic material within the soil. All other hydric soils are mineral soils with duration of

inundation, largely determining classification (Finlayson and van der Valk 1995). Hydric soils are

often affiliated with anaerobic conditions because porous structures of the soil reduce the diffusion

of oxygen. The reduction process of removing oxygen is known as “Reducing Environment”, which

is the reduction or oxidation of electrons within the soils. Reduction is the gain of electrons in the

soil; whereas oxidation is the loss of electrons in the soil. Processes of Oxidation normally resemble

a red or brown soil color, which is a result from iron in the soil. Soils that endure processes from

reduction are usually represented by a blue or gray hue. The lowering of soil potential is the last

step in the Environment Reduction process, resulting in further decomposition elements such as

sulfur (Semeniuk and Semeniuk 1995). With high variance in soil composition, it is recommended

to utilize a Munsell Soil Color Chart to correlate which soils are closely related and or present in an

area.

The overall objective of the wetlands project was to determine if a natural wetland is a more

sustainable habitat as opposed to a wetland constructed by human beings. Is there substantial

evidence that characteristics’ of a constructed wetland could be placed in any location or does it

need support from various soil types to thrive in a particular location? Lastly, could the micro

topography of a natural wetland be replicated by a constructed wetland?

Methods

Study Area. --- The study was conducted at Shaver’s Creek in Huntington County, Pennsylvania

near Petersburg, PA. Coordinates in decimal degrees for the site are as follows: 40.66599, -

77.907852. The observed study area was located within close proximity to both Shaver’s Creek and

Lake Perez. Shaver’s creek is facilitated on the eastern slope of Tussey Mountain, which is located

just north of Route 26 (Huntington County). Shaver’s creek drains a significant portion of the Penn

State Stone Valley forest (Rocco, 2013). We can classify this wetland as a “Slope” wetland; the slope

gradient was 10 degrees and the drainage basin was 6.95 square miles. The average elevation is

412m and the average temperature is 56 0F. Vegetation covers roughly 95% of the area and the

present soil types in the location were Atkins Silt Loam (Aw) and this covered roughly 47% of the

area.

The Emerick wetland is in Cambria County, Pennsylvania in Cambria Township. Coordinates in

decimal degrees for the site are as follows: 40.5256, - 78.7718. The Emerick wetlands are also

roughly 250 meters away from Scout Dam Road, which is a part of the Williams Run Reservoir. The

slope gradient for this location was six degrees and the drainage basin was 0.08 square miles. The

average elevation is 680m and the average temperature is 550F. Present soil types in the location

were Wharton silt loam, Laidig Loam; slopes of 3-8 degrees and 8-15 degrees, Hazelton Channery

Loam; slopes of 3-8 degrees and 8-15 degrees, Ernest, and Cookport loam. Cookport and Ernest

were the dominant soils of the area at about 40% coverage. All of these soils correlate to various

slope gradients.

Upon arrival of the wetland near Shaver’s creek, the first objective was to establish a suitable area

for our transit setup. In doing so we had to factor in that the transit should be set up on the upland

side of the wetland. Setting the transit up on the upland side of the wetland eliminates error when

siting the stadia rod. Considering our group was fairly large (about 6-7 people) , half of the group

finished setting up and leveling the transit; while the others measured a 50m distance across the

swamp. This distance was measured from the center of the transit to the 50m position marked

across the swamp. Once this was done, we had to clarify that the line of sight from the transit to the

50m mark was clear from all vegetation, debris, etc. to complete the setup process. It was necessary

to leave the measuring tape laid out across the swamp because we would need reference to record

other data, such as elevation. The next step was to record elevations using the stadia rod by

transitioning it in 0.5 m until we reached the 50m designation. In doing so we would have data

collections for 100 points. Elevation recordings were conducted by glancing through the transit and

identifying the measurements on the stadia rod by referencing the center stadia line. In

collaboration with the Geo313 technician holding the stadia rod, another technician recorded

observations of ground characteristics for every 0.5m increment within the 50m baseline. These

characteristic observations included ground saturation (wet or dry), and whether there was

herbaceous or non-woody vegetation, woody vegetation, coarse or fine woody debris, and barren

or denuded soil, no vegetation present.

Half of the group that was not partaking in the elevation data inquiry began to excavate two soil pits

on both the upland terrain and on the lower wetland terrain. Each pit had to be at least 20cm deep

to register an accurate reading and identification of not only dry or saturated soils; but non-hydric

and hydric soils as well. In order to establish true soil characteristics via the Munsell Soil Color

Chart, samples were taken at both 5 and 20cm depths within the pit. This would further determine

what soils were present in each soil pit.

Upon completion of soil sampling, it was apparent that the group collecting elevation data points

still had some work to do. The Geo313 technicians that recently took the soil samples took it upon

themselves to continue the lab by identifying and recording fallen debris such as trees, branches,

and ground depressions along the 50m baseline. Fallen branch measurements ranged from (1-

12cm in length), trees from (12-40cm in length), and large trees from (40cm or > in length). This

was simply conducted by walking the baseline and recording the data while walking. The

recordings were assigned to predetermined data sets in the lab as displayed in Tables 1 and 2.

Depression recordings were also broken down into predetermined data sets as displayed in Table

3. Depression count was recorded into various size classes. After the data observations were

complete for the area within the 50m baseline, each group member was responsible for repairing

the disturbed land as a result from the lab processes to the best capability.

Results

The natural wetland for Shaver’s Creek produced some prevailing evidence in correlation to

floodplain characteristics. Considering the total of one hundred observations; there were various

categories that entailed the physical characteristics of micro topographic indices. Documentation of

hydrology and vegetation at each rod location was necessary. Points were marked in order of

saturation followed immediately by vegetation cover. Saturation classifications were Dry substrate

(D), Saturated; substrate is moist but not inundated (S), Inundated; surface is covered by water (I).

While vegetation cover was classified as Herbaceous or non – woody vegetation (Vh), Woody

Vegetation (Vw), Coarse or fin woody debris (CFWD), and Barren or denuded soil, no vegetation

(B). Herbaceous or non-woody vegetation (Vh) accounted for a total of 36 points with a frequency

of 0.36% out of the total 100 points. Woody vegetation accounted for just 3 points or 0.03%, while

Coarse or fine woody debris (CFWD) contained 57 points at a frequency of 0.57%. Barren or

denuded soil, no vegetation (B) was just 4 points or 0.04% of the overall 1oo points. The total

depressions accounted for was 61 with an average depression depth was -2.6 cm. The upland soil

pit contained both silty loam and silty clay loam; silty loam at the 5cm depth and silty clay loam at

the 20cm depth. The inland soil pit contained silty loam at both the 5 and 20cm depth. There were a

total of 11 depressions along the 50m baseline that averaged a depth of 0-15cm. Concluding the

Shaver’s creek data were 4 saplings (1-12cm) and 1 tree(12-40cm). The overall soil descriptions for

the Shaver’s Creek pit are as follows: in the 5cm depths; 10YR4/3- 0-10 in, dark brown silt loam;

weak fine granular structure; friable; 10% coarse fragments; very strongly acid; abrupt smooth

boundary. In the 20cm depths;10YR5/6- 10-19 in, yellowish brown silty clay loam; weak fine and

medium block structure; slightly sticky, non-plastic; coarse fragments at 10%; very strongly acid;

gradual wavy boundary.

For the constructed Emerick wetland, 9% of the 50m baseline was dry, 26% was saturated and

54% was inundated. The baseline was composed of 30% barren land (B), 2% was coarse fine

woody debris (CFWD), 8% woody vegetation (Vw), and 60% herbaceous vegetation (Vh). The

average depression depth was -3.1 cm with an average mound height of 3.6cm out of a total 56

depression count. The Emerick pits contained both silty loam and silty clay loam at the 5cm and

20cm depths. There were a recorded 5 branches and or saplings and 0 depressions along the 50m

baseline. The overall soil descriptions’ for the Emerick wetland are as follows: In the 5cm depth

10YR4/1- 0-4 in; dark gray silt loam; weak fine granular structure; slightly plastic; many roots;

strongly acid; clear smooth boundary .In the 20cm depth; 10YR6/1- 9-46 in; gray clay loam;

common medium distinct brown and strong brown mottles(7.5YR5/6); moderate medium

prismatic structure; firm, very sticky, very plastic; many small pores; very strongly acid; gradual

wavy boundary.

Discussion

In terms of differences between the study wetland; and that of the constructed wetland micro

topography, they were actually quite subtle. Noticeable data from the soil samples was the concrete

evidence amongst the two site locations. The soil samples taken from Shavers Creek area displayed

both gleying and redox soils. Both of these soils are indicators of inundation amongst soils for a

substantial amount of time (Ricardo and Fennessy, 2002). Water accumulation at the bottom of the

wetland pit is also an indicator of hydric soils, as mentioned earlier. Also, the presence of

hydrophytic vegetation at both Shaver’s Creek and Emerick wetlands only suggest that there is

hydric soils because this type of vegetation thrives of this particular soil contrast and it is necessary

for them to establish in an area (Werner and Zedler, 2002) . So the characteristics in hydrology,

vegetation, and soil were relatively similar as discussed earlier and the only speculation I could

distinguish was landform depressions. There was a considerable amount of landform depressions

present within the natural wetland, whereas the constructed wetland had none. We can speculate

that the depressions amongst the natural wetland are present, simply because of the fact that the

land was not disturbed in any man made processes. The constructed wetland utilized

organizational processes from machinery that most likely led to a similar and or more leveled

surface area throughout this wetland.

In fact, the average mound height for the Emerick constructed wetland was 3.2cm; while the

depression depth average was -2.9cm. This would again imply that the mounds in the wetland are a

result from the machine based disturbances. As a Wetland Constructor, I would attempt to replicate

micro topography observed in natural wetlands by simply altering the processes of machine work.

Considering the land is tilled, we could either alter the process or change how the land is regulated

all together. This altering would yield higher variance throughout the wetland, hence more

accurately replicating micro topography in natural wetlands.

References

Werner, K. J. and Zedler, J.B, 2002. How sedge Meadow Soils, Microtopography, and Vegetation

Respond to Sedimentation., No. 3, September 2002, pp. 451–466

Semeniuk, A and Semeniuk V., 1995. A Geomorphic Approach to Global Classification for Inland

Wetlands. Classification and Inventory of the World’s Wetlands, No. ½ June 1995, pp. 103-124

William M.J, and Renee W.F, 1996. Improving the Success of Wetland Creation and Restoration with

Know-How, Time, and Self-Design, No. 1, February 1996, pp. 77-83

Ricardo L.D. and Fennessy M.S. 2002. Testing the Floristic Quality Assessment Index as an Indicator

of Wetland Condition, No. 2, April 2002, pp. 487-497

Finlayson M.C. and Van der Valk G.A. 1995. Wetland Classification and Inventory of the World’s

Wetlands: A Summary, No. ½, June 1995, pp. 185-192

Vivian-Smith, G. Microtopographic Heterogeneity and Floristic Diversity in Experimental Wetland

Communities. 1997. The Journal of Ecology, Vol. 85, No. 1. (Feb., 1997), pp. 71-82.

Rocco G.L., Lecture, GEOG313: Field Geography, 2013

United State Geological Survey Stream Stat Application for Pennsylvania.

http://streamstats.usgs.gov/pennsylvania.html

United States Department of Agriculture Natural Resources Conservation Service Web Soil Survey

Tool. http://websoilsurvey.nrcs.usda.gov/app/HomePage.htm

Figure 1: This diagram depicts the different types of wetlands and where they normally are

located geographically. This diagram displays not only the occurrences of where wetlands

occur, but also the processes involved.

Figure 2: Study area of the natural wetland near Shaver’s Creek, Barre Twn. PA. Location of

microtpography experiment collaborated by the Geo313 technicians’ on October 11, 2013. This map

was constructed on October 25, 2013.

Figure 3: Depiction of the constructed Emerick wetland in Cambria Township, PA. Both microtopography

and data were collected in this location. This map was constructed on October 25, 2013.

Figure 4: The Shaver’s Creek Wetland drainage basin; constructed by utilizing the USGS stream

stat tool. This depicts the water flow amounts into the basin. The figure was created on

October 25, 2013.

Figure 5: The Emerick wetland drainage basin; constructed by utilizing the USGS stream stat

stool. This depicts the water flow amounts into the basin. The figure was created on October

25, 2013.

Figure 6: Soil map for Shaver’s Creek natural wetland accompanied by the Huntington County,

Pennsylvania soil types for this location. Figure was created by utilizing the United States

Department of Agriculture Natural Resource Conservation Service website; created on October

25th, 2013

Figure 7: Using the web soil survey on the United States Department of Agriculture Natural Resource

Conservation Service website the image displays the Emerick wetland; created on October 25th, 2013.

Figure 8: The microtopography of the natural wetland near Shaver’s Creek was created by using

Microsoft Excel and it depicts the Field Observations vs. the Predicted Microtopography of the wetland

location. This graph was created on November 3, 2013

Figure 9: The microtopography of the Emerick wetland data that was previously collected in 2007, that

was later implemented in an Excel spreadsheet . This graph depicts the microtopography of both the

predicted and field observations for this wetland. This graph was created on November 3, 2013

0

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1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88 91 94 97 100

FieldObs.

0

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1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88 91 94 97 100

FieldObs.

Table 1: The different sizes of woody debris and how many times a specific size class of tree

was observed along the 50 meters of wetland that the Geog313 group I participated in; was

measuring during the lab in the natural wetland near Shaver’s Creek on October 12, 2012.

Table 2: Dedifferentiation amongst woody debris and how many times a specific size class of tree was observed along the 50 meters of the Emerick wetland. The data was collected in August 6, 2007.

Size Class Midpoint Count Total

Branches and Fallen Saplings

(1-12 cm)

6 cm (2.3in) 5

Trees ( >12-40 cm) 26 cm (10.1in) 0

Large Trees ( >40 cm) N/A 0

Table 3: Counts of micro topographic depressions to see how many dips were present in the 50 m section of the wetland being observed by the Geog313 group I was in during the lab period on October 12, 2012.

Depth Class (cm) Count Total

0-15 11

15-30 0

30-45 0

>45 0

Size Class Midpoint Count Total

Branches and Fallen Saplings (1-12cm)

6 cm (2.3 in) 4

Trees (>12-40cm) 26 cm (10.1 in) 1

Large Trees (>40cm) N/A 0