EPA 600/R-08/055 I January 2008 I www.epa.gov/ada
United States
Environmental Protection
Agency
Effectiveness of Restored
Wetlands for the Treatment of
Agricultural Runoff
Office of Research and Development
National Risk Management Research Laboratory, Ada, Oklahoma 74820
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Effectiveness of Restored
Wetlands for the
Treatment of Agricultural Runoff
Mark A. Biddle, Robin M. Tyler
Thomas G. Barthelmeh
Delaware Department of Natural Resources and
Environmental Control
Timothy J. Canfield
Project Officer, Robert S. Kerr Environmental
Research Center
Office of Research and Development
National Risk Management Research Laboratory, Ada, Oklahoma 74820
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Notice
The U.S. Environmental Protection Agency through its Office of Research
and Development managed the research described here under EPA Coop-
erative agreement Contract No. R-831245 to Delaware Department of Natural
Resources and Environmental Control (DNREC), through funds provided by the
U.S. Environmental Protection Agency's Office of Research and Development,
National Risk Management Research Laboratory, Ada, Oklahoma, and U.S.
Environmental Protection Agency - Region 3 as part of the Regional Applied
Research Effort (RARE). It has been subjected to the Agency's peer and ad-
ministrative review and has been approved for publication as an EPA document.
Mention of trade names or commercial products does not constitute endorse-
ment or recommendation for use.
All research projects making conclusions or recommendations based on
environmental data and funded by the U.S. Environmental Protection Agency
are required to participate in the Agency Quality Assurance Program. This proj-
ect was conducted under an approved Quality Assurance Plan. Information on
the plan and documentation of the quality assurance activities and results are
available from the lead author.
Reference as: Biddle, M.A., R.M.Tyler, T.G. Barthelmeh, and T.J. Canfield.
Effectiveness of Restored Wetlands for the Treatment of Agricultural Runoff.
Delaware Department of Natural Resources and Environmental Control, Dover,
Delaware. 2007.
Mark A. Biddle, Robin M. Tyler, and Thomas G. Barthelmeh
Delaware Department of Natural Resources and Environmental Control
89 Kings Highway
Dover, Delaware 19901
Timothy J. Canfield, Project Officer
U.S. Environmental Protection Agency
Office of Research and Development
National Risk Management Research Laboratory
Ada, Oklahoma 74820
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Foreword
The U.S. Environmental Protection Agency is charged by Congress with protecting the Nation's land, air, and water
resources. Under a mandate of national environmental laws, the Agency strives to formulate and implement actions
leading to a compatible balance between human activities and the ability of natural systems to support and nurture
life. To meet this mandate, EPA's research program is providing data and technical support for solving environmental
problems today and building a science knowledge base necessary to manage our ecological resources wisely,
understand how pollutants affect our health, and prevent or reduce environmental risks in the future.
The National Risk Management Research Laboratory is the Agency's center for investigation of technological
and management approaches for preventing and reducing risks from pollution that threatens human health and the
environment. The focus of the Laboratory's research program is on methods and their cost-effectiveness for prevention
and control of pollution to air, land, water, and subsurface resources; protection of water quality in public water
systems; remediation of contaminated sites, sediments and ground water; prevention and control of indoor air pollution;
and restoration of ecosystems. NRMRL collaborates with both public and private sector partners to foster technologies
that reduce the cost of compliance and to anticipate emerging problems. NRMRL's research provides solutions
to environmental problems by: developing and promoting technologies that protect and improve the environment;
advancing scientific and engineering information to support regulatory and policy decisions; and providing the technical
support and information transfer to ensure implementation of environmental regulations and strategies at the national,
state, and community levels.
The goal of this report is to provide information on the effectiveness of restoring small wetlands in agricultural areas
to intercept surface water runoff and attenuate nutrients and suspended sediments in these surface waters. This report
describes the history of drainage practices in the State of Delaware, the relatively recent practices of wetland and stream
corridor restorations in Delaware, and the projected benefits of these restorations practices on the waters of Delaware.
Due to the ability of wetlands to sequester and process nutrients and sediments, they are being implemented more
frequently as a means of restoring lost ecosystem services such as water quality and water quantity. Although this
report provides some valuable information regarding performance of these small wetland systems, climatic conditions
limited the amount of data that could be collected and prevented a full assessment of how effective these systems might
attenuate nutrients and sediments. Identifying specific cause-effect relationships was not possible with the limited data
collected, but general trends in some of these relations is presented. This report does provide a solid foundation and
a jumping off point for additional work to evaluate the effectiveness of these small wetland systems across a broader
array of agricultural landscapes, with the goal of filling in the data gaps that still exist which limit the use of these
systems in a comprehensive watershed management program.
Stepbien G. Schmelling, Director
Ground Water and Ecosystems/Resforation Division
National Risk Management Rpseapch Laboratory
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Contents
Synopsis xiii
Executive Summary xiii
Background Information 1
Historical Summary of Delaware Drainage Practices 1
Wetland Restoration in Marginal Agricultural Fields 2
Stream Corridor Restoration 2
Benefits of Ecological Restoration 3
Methods 5
Sampling Sites 5
Sampling Approach 5
Statistical Analysis 7
Results 9
Overall Concentration Observations 9
Sampling Event and Sampling Site Effects 9
Individual Cells and Perennial Stream 9
Collective Inflows and Outflows 9
Discussion and Conclusion 13
References 17
Appendices 19
Appendix 1 19
Appendix 2 21
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Figures
1. Photos:
a. Aerial photo of the Haines Farm site (Kent County, Delaware) prior to construction. 1997 .... 6
b. Aerial photo of the Haines Farm site (Kent County, Delaware) during construction of the
restored stream. 2002 6
c. Aerial photo of the Haines Farm site (Kent County, Delaware) after all construction and
during sampling. 2004 7
2. Means plots with Tukey HSD 95% intervals 10
3. Box plots for TP, SRP, TN, NO3+NO2, NH3, and TSS 11
4. Bar graphs with concentrations of TP, SRP, TN, NO3+NO2, NH3, and TSS 12
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Tables
1. Water quality variables analyzed for the RARE exploratory restored wetland
monitoring project 14
2. Comparisons of Inflow vs. Outflow concentrations for selected species and total
suspended solids 14
3. Concentration comparisons between Inflow and Outflow for selected nutrients and
total suspended solids 15
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Acknowledgment
We would like to thank N. Kemble, B. Perkins, and S. Turley for their constructive comments on the manuscript.
M. Williams for developing the layout and design of this report into the EPA publishing format. Cover Photos were
provided by T. Barthelmeh. The U.S. Environmental Protection Agency-Region 3 funded this research effort, as part of
the Regional Applied Research Effort (RARE) program. The U.S. EPA Office of Research and Development, National
Risk Management Research Laboratory, Ada, Oklahoma, managed the research effort described within this report
through collaboration with the Delaware Department of Natural Resources and Environmental Control (DNREC). It
has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA
document.
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Executive Summary
Synopsis
1. Current water management and drainage activities in Delaware afford opportunities to implement site-specific,
ecologically beneficial projects which can be incorporated into comprehensive watershed management plans.
2. These projects apply construction techniques intended to improve degraded water quality in watersheds throughout
Delaware.
3. Current research indicates that multiple management practices including vegetated riparian buffers, wetland
restoration, and stream channel restoration can retain and assimilate nutrients (nitrogen and phosphorus) and retain
suspended solids from agricultural runoff.
Executive Summary
Throughout the Delmarva Peninsula drainage activities that commenced during colonial times and intensified during
the 20th century have resulted in the creation of extensive ditch systems through the generally flat, alluvial soils for the
purpose of rapidly removing water in order to support agriculture and human habitation. Ditching frequently involved
extending surface water systems (ditches) into areas that were naturally perennial or seasonal wetlands, resulting in the
drainage of these forested wetlands and the lowering of the local water table. The straight configuration of the ditches
and the straightening, widening, and deepening of some perennial nontidal stream channels expedited flow downstream
and accommodated the larger volumes of storm flow coming from the watershed which were no longer being retained
by wetlands. The large decrease in storm water residence time on the land and the larger volumes resulted in greatly
elevated loadings of sediments and nutrients to downstream lower energy waters (i.e., lakes/ponds, tidal rivers,
estuaries). The ensuing shallowing and occurrences of algal blooms triggered by nutrient enrichment in these low
energy "receiving" waters have impacted both human economic activities and ecological health to varying extent which
in some cases has been catastrophic.
In Delaware since the 1990's there has been substantial and increasing effort to reestablish some of the wetland acreage
that has been lost over the past 300 years. Such restoration is part of a broader strategy to develop comprehensive
watershed management plans as part of TMDL driven Pollution Control Strategies. The objective of this work has
been to enhance the sediment/nutrient retention capability within watersheds, with an ultimate goal of achieving
improvement in economic and ecological condition in areas that have been impacted by the reduction or elimination
of the buffering functions afforded by wetlands. This exploratory project represents the first concerted effort by the
State of Delaware to obtain some water quality data from a restored wetland and adjacent riparian corridor in order to
examine the interception and retention of sediments and nutrients transported in overland runoff from agricultural fields.
The main element of this project involved water sampling during five rain events large enough to generate overland
runoff from corn and soybean fields on a farm in west-central Kent County, Delaware. Samples were collected from
the inflows and outflows of three restored wetland cells and a perennially flowing ditch (Iron Mine Prong) above and
below the area into which the wetlands discharge. Concentrations of sediments (measured as total suspended solids -
TSS), total nitrogen (TN), total phosphorus (TP), and dissolved inorganic fractions thereof including nitrate + nitrite
(NO3 + NO2), ammonia (NH3), and soluble reactive phosphorus (SRP) were determined. The conclusions of the current
study are limited due to insufficient resources to quantify fluxes and, due to the small dataset. We recommend that the
results be interpreted cautiously despite some statistically significant differences between sampling events and sites.
It was understood entering the study that TSS and nutrient concentrations can vary substantially over the course of a
storm hydrograph and that the results from samples grabbed at some unknown point in the hydrograph curve are of
limited usefulness. However, it also seemed reasonable that the sampling of multiple storm events might improve the
understanding regarding the range of nutrient levels that occur in storm water runoff from a typical Delaware farm
field under known agricultural activity. This may allow some patterns to be developed that would be beneficial to the
planning of more comprehensive studies that do involve flux determination.
Among all four wetland inflows (one of the wetlands had two inflows) and across all five storm sampling events, ranges
for constituents in mg I'1 were as follows: TSS (7 - 58), TN (1.06 - 4.77), NO3 + NO2 (0.018 - 2.33), NH3 (0.011 -
1.01), TP (0.65 - 5.36), SPJ3 (0.55 - 4.14). Among all three wetland outflows and across all five storm sampling events,
ranges for constituents in mg I'1 were as follows: TSS (5 - 78), TN (0.90 - 3.76), NO3 + NO2 (0.017 - 1.92), NH3 (0.017
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- 0.70), TP (0.55 - 3.13), SRP (0.38 - 3.18). In Iron Mine Prong, concentrations did not differ between the two sites for
any constituents and were generally lower than wetland inflows and outflows, particularly on the high end of the range.
The highest levels measured at the Iron Mine Prong site below the wetland discharge were as follows for TSS (59), TN
(1.89), NO3 + NO2 (0.86), NH3 (0.37), TP (0.53), SRP (0.35). This difference on the higher end of the ranges between
Iron Mine Prong and the wetlands shows that at this level of sampling the volume of runoff entering the stream from the
wetlands was relatively small with a sediment/nutrient load insufficient to have measurable impact on the much higher
volume of water flowing in from higher in the watershed. This difference in volume between the wetland outflows and
Iron Mine Prong was apparent visually at the time samples were collected. For Iron Mine Prong, TSS, TP and SRP
levels were about an order of magnitude more during storm events than during baseflow. Differences between baseflow
and stormflow were not apparent for any nitrogen constituents.
The findings of this study indicate a need to conduct future work which is particularly focused on P dynamics
associated with wetland cells, shapes and sizes of wetlands cells, retention time, flow volumes and concentration
variability over storm hydrographs.
Keywords: agriculture, Clean Water Act, nitrogen, nutrients, phosphorous, retention, riparian, runoff, watershed, water
quality, wetlands.
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1.0
Background Information
Historical Summary of Delaware
Drainage Practices
Delaware is located on the Delmarva Peninsula between
Chesapeake Bay and Delaware Bay with 91% of the
geomorphic classification being coastal plain (Maxted
1995). This alluvial, generally flat land is characterized
as well to poorly drained with loamy or sandy soils and
loamy to clayey subsoil (Tiner 1985). Approximately
37% of Delaware is overlain by poorly drained soils,
with a high water table during most of the year (DNREC
2004). Average rainfall in Delaware usually exceeds
plant needs and evaporation rates (DNREC 2004). This
combination of topography, soil and climate conditions
has posed a drainage problem since colonial settlement
to farmers who have cleared most of the native forest for
agricultural use.
In Delaware, there are community and private drainage
systems dating back to the 1700's. These drainage
ditch systems are inland extensions of natural perennial
stream channels. These ditches were constructed
to manage soil and water resources for agricultural
purposes, and to provide flood protection. Without an
effective drainage system, poorly-drained soils become
saturated or flooded, thereby diminishing or eliminating
agricultural productivity and creating problems for
residential landuse. Several decades ago, the Delaware
General Assembly enacted the 1951 Drainage Law to
establish, finance and maintain drainage organizations
(i.e. tax ditch organizations - referred to hereafter as
"organization/s). Formation of an organization can
only be initiated by landowners who petition Superior
Court to resolve drainage or flooding concerns. This
petition results in the Conservation District requesting
an investigation by the Delaware Department of Natural
Resources (DNREC) Division of Soil and Water
Conservation (DSWC) to ".. .determine whether the
formation of an organization and construction of a tax
ditch system is practicable and feasible, and is in the
interest of the public health, safety and welfare." If so
determined, the Conservation District files the petition in
Superior Court, and the Board of Ditch Commissioners
(as directed by the resident judge) prepares a report on
the proposed tax ditch.
Thus, these community drainage systems (tax ditches)
are governmental subdivisions of the State and are
watershed-based landowner organizations formed
by a prescribed legal process in Superior Court. An
organization is comprised of all landowners (also
referred to as Taxables) in a particular watershed
(drainage area) or sub-watershed. The operations of
an organization are overseen by ditch managers and
a secretary/treasurer who are landowners within the
watershed. These "officers" are elected at an annual
meeting by the Taxables. To date, 228 organizations
exist statewide which manage more than 2000 miles of
ditches (channels) that serve more than 100,000 residents
and over half of the state-maintained roads. The 2000
miles of ditches, with the help of approximately another
2000 miles of private (on farm) drainage systems,
provide water management service for more than
350,000 acres (~ 1/3) of land in Delaware. System
drainage areas range in size from 2 acres to 56,000 acres,
while ditches range in size from 6 to 80 feet wide and 2
to 14 feet deep. Ditch dimension is dependent upon the
acreage being drained and topography.
The DSWC assists by planning, implementing, and
administering the Water Management Program, which
includes tax ditches. Once a tax ditch plan is approved
the system is ready to be constructed. Construction
is usually done by the Conservation District, utilizing
equipment and operators in the respective County.
Historically, these operators utilized construction
methods that achieved the singular goal of rapidly
removing excess water from the land without
ecological consideration. Around 1990 efforts began
to educate and train these planners and operators to
develop and construct drainage projects in ecologically
sensitive ways. Since then the DNREC has focused
on constructing ecologically sensitive drainage/water
management projects. This shift in focus has resulted in
the development of numerous practices that have been
demonstrated to reduce ecological impacts resulting
from the initial construction and subsequent maintenance
of tax ditches. In addition to performing on-site
management practices to reduce direct impact, the water
management program has instituted measures to mitigate
for these impacts and go further by implementing
practices that enhance, create and restore habitats along
these ditch corridors. These practices are supported by
a requirement from former Governor Castle's Executive
Order No. 56 (1988) that mandates state agencies to
achieve no-net wetland loss with their projects (Gov.
Castle EO-56 1988).
The following list of practices has evolved into the
Delaware Tax Ditch Best Management Practices manual.
Some of the more prominent best management practices
(BMP/s) include:
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• minimizing clearing widths through forested areas;
• relocating channels around sensitive habitat or
wetland areas;
• installing structures to control water levels in the
channels;
• performing one-sided construction;
• saving trees within the construction zone;
• minimizing construction of downstream outlets;
• installing a berm along the channel with an inlet
pipe to maintain the historical water level in adjacent
wetlands
• blocking off old channels that drain only wetland
areas.
Recent Water Management Program efforts have also
included the construction of wetland restoration "cells"
adjacent to active agricultural fields. The "cells"
intercept agricultural runoff before it enters an adjacent
ditch or natural stream channel. In other instances
wetland cells are established in-line and upstream of
restored channels, with surface water flow generated
from field run-off. While these projects are primarily
designed to function as wildlife habitat, they can also
provide water quality benefit by sequestering suspended
sediments and nutrients. Additionally, a few of these
projects have instituted stream corridor restoration of
highly degraded streams and adjacent floodplains to
natural stream morphology.
To ensure BMPs implementation, the DNREC routinely
provides wetland/ environmental training sessions for
both technical and administrative staff members. The
DNREC has constructed several projects incorporating
BMPs to test their effectiveness. These projects have
resulted in the establishment of sites which demonstrate
that economically necessary drainage and ecological
quality can be mutually beneficial.
Wetland Restoration in Marginal
Agricultural Fields
Throughout Delaware, agricultural operations are
performed on a variety of fields with varying soil types,
shapes, and sizes. Opportunities for ecologically-
focused wetland restoration or creation are particularly
strong where an area of marginally productive,
poorly drained soil overlaps with an area that has a
configuration that complicates tillage such as a point
or corner. Historically, most poorly-drained portions
of fields were forested wetlands. The reestablishment
of wetlands in these areas results in ecological benefits
which include creation/enhancement of wildlife habitat,
increased biodiversity, and reduction in the rate at which
stormwater runoff is discharged to contiguous streams.
The reductions in water volume and nutrients represent
measurable indicators which may be used to demonstrate
improvements in water quality and overall stream
character. Examples of potential benefits to farming
operations from such wetland restoration efforts include
(1) the removal from production of portions of marginal
and non-productive fields and (2) the opportunity to
re-contour the remainder of the field in a manner that
further enhances crop production while the equipment is
onsite.
Until recently wetland restoration technique was limited
largely to the construction of open-water ponds, which
exhibit relatively low plant and animal diversity. Recent
efforts have focused on a variety of techniques that
encourage a high diversity of plant and animal species.
These techniques include the construction of micro-
topography (humps and bumps), addition of organic
matter, placing coarse woody debris, relocation of trees
and shrubs, and creation of irregular shapes. These
detailed techniques have proven to "jump-start" initial
macroinvertebrate and amphibian establishment in
restoration projects (Alsfeld et al. 2005) and result in
projects that closely replicate natural wetlands (DNREC
2004).
Much of the construction is performed using relatively
small equipment. AD-6 dozer, used in conjunction
with medium sized backhoes and excavators, is all that
is needed to accomplish the water management and
restoration goals for each project. Using this small
equipment and the operators from the local Conservation
Districts has kept overall project costs down. For
example, the cost of constructing a one-acre wetland
typically ranges between 2,500 and $4,500, including
excavation, spreading of soils, lining with clay soil
layers, replacement of top spoil, planting of trees/shrubs/
emergent vegetation, relocation of large trees, addition
of course woody debris, addition of organic material,
seeding, and any needed pipe/s or outlet structure/s.
Stream Corridor Restoration
Activities such as agriculture, road-building, residential
and commercial development and drainage have resulted
in the degradation of much of Delaware's nontidal
stream and riparian (the area interfacing and fringing
a stream) habitat. These activities have altered the
state's aquatic habitats, water-dependent species and
surrounding upland environments. The DNREC has
estimated that 90 percent of Delaware's streams and
rivers have been modified.
To address these concerns the DNREC has initiated an
effort to restore stream corridor habitats. The overarch-
ing goal of stream corridor restoration projects is to re-
store highly disturbed and/or degraded streams and their
surrounding riparian areas to natural, stable stream chan-
nels with high ecological functionality. Specific objec-
tives include: 1) restoration of degraded stream channels
to a more natural morphology; 2) re-establishment of
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biological diversity; 3) reduction in surface water pollut-
ants; 4) increase in wildlife habitat; and 5) protection and
improvement in water quality.
Presently, stream corridor restoration efforts are
implemented when private landowners request
restoration projects or when DNREC personnel have
located potential sites on state-owned lands. The
restoration projects completed have been successful
in restoring wetland and upland habitat, and providing
natural stream channel stability.
Recent projects have focused on using geomorphic
approaches to convert ditches that are straight, exhibit
rapid water discharge, and are steep-sided with minimum
riparian vegetation to channels that are sinuous, exhibit
reduced flow rates, and have wider, naturally vegetated
flood plains. Other efforts have focused on restoring
degraded natural streams to provide long-term physical
stability and improve ecological value.
Benefits of Ecological Restoration
• Increase and enhance aquatic habitat and wildlife
habitat
• Retention and uptake of nutrients and sediments to
improve water quality
• Promote the establishment of native plant species and
control invasive species
• Protect rare and endangered species
• Increase recreational opportunities - bird watching
and hunting
• Stream bank stabilization
• Aesthetics and education
• Ground-water recharge, water storage and flood
control
It appears that greater success may be achieved by
creating wetlands in many smaller cells in strategic
places rather than constructing fewer large systems.
Landowners are more agreeable to selectively
constructing small cells in areas that are problematic
for farming. Additionally, the cost effectiveness of
strategically placing many smaller cells better allows
for concentration on specific areas which contribute
disproportionately to stream degradation, in essence
potentially having a more positive effect on adjacent and
downstream water quality than by creating a very large
wetland in one area.
The creation and positioning of small wetland cells
between agricultural fields and surface water streams
to intercept some proportion of the nutrient load being
discharged from the fields during storm events would
seem to have potential for widespread application as
an alternative for water quality protection, remediation,
or enhancement. The objective of this exploratory
project was to obtain some baseline data to examine
differences in concentrations of suspended sediments
(total suspended solids) and nutrients (nitrogen and
phosphorus) between stormwater runoff flowing into
and out of three small, constructed wetland cells. Due
to nutrients and habitat degradation being primary issues
Delaware is currently implementing Total Maximum
Daily Loads (TMDL's) in many watersheds (DNREC
2006). This baseline data is considered important to the
future development of a larger, more comprehensive
study to quantify loadings of such variables and thereby
better understand the extent to which man-made
wetlands function as buffers against eutrophication and
sedimentation in downstream waters.
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2.0
Methods
Sampling Sites
The restored wetlands evaluated during this exploratory
project were constructed to replicate natural wetland
systems. They are not simply "pond/open water"
systems. Rather, the "cells" contain the following
natural features which enhance ecological functioning.
A primary feature is "microtopography" which promotes
diversity in plant and animal communities. Additionally,
organic matter (e.g., straw) and coarse woody-debris
are added to facilitate biological activity and provide
habitat. Relocated live trees further enhance nutrient
assimilation. The ages of the cells are approximately 4
to 5 years. In addition to the initial plantings they are
vegetating naturally through succession.
For this project, the DNREC reviewed over 200 potential
sites and along with the USEPA visited approximately
30 of the more promising sites. A total of 12 sites were
then preliminarily selected: nine sites were wetlands that
were restored within the past 2 to 8 years; three sites
were constructed specifically for this project. Based
on limited resources, three farms, Haines, Pratt, and
Kolakowski were selected for sampling. However,
because of prolonged drought conditions and insufficient
amounts of runoff at Pratt and Kolakowski, only the
Haines site was sampled (see note).
(Note: The Kolakowski site has two wetland cells
which both outlet into the same hedgerow ditch with a
watershed drainage area of approximately 8 acres total
with cell sizes of .5 acre and .7 acre. The Pratt site has
two cells in-line which empty into a restored stream
similar to Haines. Watershed drainage area at Pratt is
10.5 acres with cell sizes of 1.6 acres and 1.3 acres.)
Figure la-c shows the Haines site (a) prior to
construction, (b) following addition of meanders to
the channel of Iron Mine Prong, a perennially flowing
ditch, and (c) following completion of the wetland cells.
Runoff of stormwater from the fields is routed into three
independent wetland cells which discharge to Iron Mine
Prong (Figure Ic). Approximately 12 acres of fields
drain into Wetland Cell 2, while Wetland Cells 1 and
3 have approximately 4 acres each of field drainage.
Wetland Cells 1 and 3 have a single inflow whereas
Cell 2 has two inflows. Each wetland cell has a single
outflow. Individual cell sizes were: Cell 1 = .25 acre;
Cell 2 = .45 acre; and Cell 3 = .5 acre. Drainage area
upstream of the project site is approximately 1260 acres.
The crop fields at the Haines site are in typical
continuous corn/wheat/soybean rotation. Fertilizer
rates for these crop fields are unknown although they
are assumed to be current Delaware Department of
Agriculture application recommendations from year
to year. Precipitation events and their magnitude
which coincided with sampling dates can be found in
Appendix 2.
Sampling Approach
Field sampling and laboratory analysis were conducted
by the DNREC Environmental Laboratory Section,
which is an EPA certified lab, according to EPA
approved methods and the State of Delaware (2004).
Monitoring began in early-April 2005. Seven sampling
events occurred, two under baseflow conditions and five
under stormflow conditions. Events 1, 2, and 5 occurred
during October and November, Event 3 occurred
during late-June, and Event 4 occurred during early
September. During the baseflow events, sampling was
limited to the Iron Mine Prong along which two sites
were sampled (Figure Ic). These sites, S-l and S-2,
were upstream (inflow) and downstream (outflow) of the
wetland discharge area, respectively. Sampling during
the stormflow events included Iron Mine Prong plus the
inflow and outflow sites for each of the three wetland
cells (Figure Ic). Outflow samples were collected from
the discharge pipe of each wetland cell whereas inflow
samples were collected from swales or shallow ditches
cut into the field to direct runoff.
During each sampling event a single grab sample
was taken from each site and subsequently tested for
nutrients (phosphorus and nitrogen), total suspended
solids and pH (Table 1). Samples were placed
on ice in the field and processed in the laboratory
according to procedures provided in Table 1. There
was no determination of water flow, thus variability in
concentration over the respective storm hydrographs
and fluxes is unknown. Analysis was done for total
phosphorus (TP) and total nitrogen (TN) because those
variables are primary eutrophication targets for Delaware
TMDLs, and for dissolved fractions thereof including
soluble reactive phosphorus (SRP), nitrate + nitrite
nitrogen (NO3 + NO2) and ammonia (NH3) due to the
direct response potential of these constituents for fueling
aquatic plant growth. Total suspended solid (TSS) was
sampled as a surrogate for suspended sediments in the
water. The data for all variables tested is provided in
Appendix 1.
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mm
Figure la. Aerial photo of the Haines Farm site prior to construction of wetland cells and stream restoration of Iron
Mine Prong. 1997. (North is top of photo).
Figure Ib. Aerial photo of Haines Farm site during construction of the stream restoration of Iron Mine Prong and
prior to wetland cell construction. 2002 (North is top of photo).
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Figure Ic. Aerial photo of Haines Farm site (Kent Co., Delaware) with labeled sample locations 2004. (North is
bottom of photo).
Statistical Analysis
All statistical testing was done using STATGRAPHICS
PLUS Version 5.0. The significance level selected for
rejection of the null hypothesis is a = 0.05.
Two major factors expected to affect variable
concentrations included sampling event and sampling
site. Their effects were tested using a mixed model Two-
Way ANOVA without replication, with sampling event
as the random factor and sampling site as the fixed factor
(Zar 1999).
Differences between inflow and outflow concentrations
for the individual wetland cells (n = 5 per site) and
Iron Mine Prong (n = 7 per site) were tested using the
nonparametric Wilcoxon paired-sample test (Zar 1999).
For Cell 2, the inflows were not averaged because the
influence of each upon the outflow was unknown due to
the lack of flow data. Tests were one-tailed because it
was expected that outflows would be lower than inflows
due to the retention function of the wetlands.
Differences in concentrations between the outflows and
differences between the inflows were tested using the
nonparametric Friedman's test (Zar 1999) for block
designs. The nonparametric tests were used primarily
because the small data sets frequently violated the equal
variance requirement for using parametric tests.
The testing processes for differences between (1)
sampling events, (2) inflow and outflow for the wetland
cells and Iron Mine Prong, and (3) the differences
between inflows and between outflows each involved
the running of several consecutive tests. Such repetition
increases the chance for making a Type 1 error. To
protect against committing a Type 1 error a conservative
approach to the analysis is to divide a by n (Holm 1979).
Thus, for (1), six tests were run (n = 6 variables). The
adjusted significance level is P = 0.008 (0.05 / 6). For
(2), for each variable there were five comparisons (n
tests) run; C-l I vs. O, C-2 I2a vs. O, C-2 I2b vs. O, Cell
3 I vs. O, and Stream I vs. O. The adjusted significance
level is P = 0.01 (0.05 / 5). For (3), for each variable
there were two tests run thus the adjusted significance
level is 0.025. P values < 0.05 are recognized in the
analysis but are regarded as suggestive rather than
significant.
-------
-------
3.0
Results
Overall Concentration Observations
Among all four wetland inflows and across all five storm
sampling events, ranges for constituents in mg I'1 were
as follows; TSS (7 - 58), TN (1.06 - 4.77), NO3 + NO2
(0.018 - 2.33), NH3 (0.011 - 1.01), TP (0.65 - 5.36),
SRP (0.55-4.14). Among all three wetland outflows
and across all five storm sampling events, ranges for
constituents in mg I'1 were as follows; TSS (5 - 78), TN
(0.90 - 3.76), NO3 + NO2 (0.017 - 1.92), NH3 (0.017 -
0.70), TP (0.55 - 3.13), SRP (0.38 - 3.18). InlronMine
Prong, concentrations did not differ between the two
sites for any constituents and were generally lower than
wetland inflows and outflows, particularly on the high
end of the range. The constituents likely were broken
down through natural processes, plant uptake, or had
traveled downstream in suspension (i.e. phosphorous).
The highest levels measured at the Iron Mine Prong
site below the wetland discharge were as follows for
TSS (59), TN (1.89), NO3 + NO2 (0.86), NH3 (0.37), TP
(0.53), SRP (0.35).
Sampling Event and Sampling Site
Effects
When all nine sites were included in the Two-Way
ANOVA, the random factor, Event, had a highly
significant effect on TN, NO3 + NO2, NH3 and TSS
(P < 0.01). An approaching significant effect was
obtained for TP (P = 0.046) while SRP was insignificant
(P = 0.286). Concentration means for each of the
variables were generally highest after Event 3 (Figure 2).
This was the only sampling event that occurred during
the peak growing season. No other Event patterns were
evident. When the model was run separately for the
combined wetland cell inflows (four sites) and combined
outflows (three sites), Event was no longer significant
forTP.
The fixed factor, Site, had a highly significant effect
on TP, SRP, and TN (P < 0.01) but no significant effect
on NO3 + NO2, NH3, and TSS (P = 0.05). When the
model was run separately for the combined inflows and
combined outflows, TN was only significant for the
outflows (P = 0.015). Site differences are identified
below.
Individual Wetland Cells and Iron Mine
Prong
Comparison of Inflow vs. Outflow concentrations show
that TP and SRP concentration were significantly greater
in the inflows of Cells 1 and 3 than in the outflows
(Table 2, Figure 3), and that TN concentrations were
significantly higher in Iron Mine Prong above the
wetland cells than below the cells (Table 2). For TN,
Figure 4 shows that while the paired above vs. below
differences were small, they were consistent. For
concentrations of all other variables, inflow vs. outflow
comparisons were not significant at P = 0.05 (Table 2).
Collective Wetland Inflows and
Outflows
Differences between wetland cell inflows and between
outflows were significant for TP and SRP at P = 0.05
(Table 3, Figure 3). Differences between NO3 + NO2
among the outflows were also significant at P = 0.05
(Table 3, Figure 3). For all other variables inflow and
outflow comparisons were not significant at P = 0.05
(Table 3, Figure 3). Once again, the data analysis
process involved running several consecutive similar
tests therefore the significant results for SRP inflow and
NO3 + NO2 outflow should be considered cautiously.
-------
z
1-
4
3
2
1
n
: I
I
I
I
I !
1.3
1
ff 0.7
z 0.4
0.1
-0.2
CO
0.74
0.54
0.34
0.14
n nc
~
-
! I
I
I
I
-
-
•
I \
50
40
CO 30
CO
"~ 20
10
0
2.4
2.1
1.8
1.5
1.2
0.9
0.6
LO
in
CV
ID
CM
CV
CD
CO
CD
co csl co
CM O ,-
CD 5> ^
2.1
1.8
0. 1.5
o:
W 1.2
0.9
0.6
: :
-
-
~
-
'
-
-
t
~
-
in m CD CD co
o fa o o g
in cv CD Si co
CM C\l CM £3 T-
o ^ co 55 ^
Figure 2: Means plots with Tukey HSD 95 % intervals for Total Nitrogen (TN), Nitrate + Nitrite Nitrogen (NO3
+ NO2), Dissolved Ammonia (NH3), Total Suspended Solids (TSS), Total Phosphorus (TP) and Soluble
Reactive Phosphorus (SPJ3) inclusive of all storm sampling events for nine sites (wetland inflows,
outflows and perennial receiving stream) located on the Haines Farm, Kent County, Delaware. All units
are milligrams per liter. See Figure 1 for site locations.
-------
Inflow
Outflow
co
O
2
1
0
5
4
3
2
1
0
2.4
2
1.6
1.2
0.8
0.4
0
1.2
1
0.8
0.6
0.4
0.2
0
80
60
CO
CO 40
20
CO
X
I
i
1
2a
2b
6
5
4
& 3
2
•|
5
4
£ 3
CO 9
5
4
Z 3
I—
2
1
2.4
2
co 1-8
0 1.2
0.8
0.4
Q
1.2
1
CO0'8
|0,
0.4
0.2
0
80
60
CO
W 40
20
n
- T ;
-i
D
— =~~ "~ ;
a :
" T ' '
.
i i
' I , :
- ' ' - ± ;
D
T -
~r | |
.' _L ' J. _L .
•
•
•
D
D
T | 1
I 1
.
Site
1
Figure 3: Box plots for Total Phosphorus (TP), Soluble Reactive Phosphorus (SRP) Total Nitrogen (TN), Nitrate +
Nitrite Nitrogen (NO3 + NO2), Dissolved Ammonia (NH3), and Total Suspended Solids (TSS), inclusive
of five storm sampling events for wetland cell inflows and outflows on the Haines Farm, Kent County,
Delaware. All units are milligrams per liter. See Figure 1 for site locations.
-------
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
3.00
2.50
2.00
1.50
1.00
0.50
0.00
0.40
0.35
0.30
0.25
'0.20
0.15
0.10
0.05
0.00
I
1.00
0.90
0.80
0.70
0.60
0.50
0.40
0.30
0.20
0.10
0.00
3.00
IfllJ
II
2.50
2.00
CM
O
+ 1.50
CO
1.00
0.50
0.00
70
60
50
40
0
- 30
20
10
0
BBfllmB
1
Figure 4: Concentrations of Total Phosphorus (TP), Soluble Reactive Phosphorus (SRP) Total Nitrogen (TN),
Nitrate + Nitrite Nitrogen (NO3 + NO2), Dissolved Ammonia (NH3), and Total Suspended Solids (TSS),
inclusive of 2 base flow (4/06/05 and 10/24/05) and five storm sampling events for a perennial coastal
plain stream which flows through the Haines Farm, Kent County, Delaware. White bars represent farm
inflow (above wetland cells). Black bars represent farm outflow (below wetland cells). All sampling was
done in the perennial stream. All units are milligrams per liter. See Figure 1 for site locations.
-------
4.0
Discussion and Conclusions
New techniques in water management in Delaware are
resulting in opportunities for environmentally sensitive
construction which includes wetlands restoration/
creation and stream restoration. Developing beneficial
watershed management plans which include BMPs and
pollution control strategies (from TMDLs) may prove to
be important in achieving improvement in overall water
quality. As part of a watershed management plan, it is
anticipated that the creation and restoration of many
small wetlands and the restoration of stream channels
in combination with the restoration of riparian buffers
may have a cumulative and measurable effect on water
quality. Each of these actions can be done quickly,
efficiently and at low-cost.
Buffers are widely recognized as helpful in sequestering
nutrients before they enter downstream waters.
Generally, and vegetation type dependent, narrow
buffering (<15m) removes some nitrogen while wider
buffers of greater than 50 m perform more consistently
and remove larger amounts of nitrogen (Mayer et al.
2006). By positioning many small wetland cells within
buffered areas which receive agricultural runoff, perhaps
a higher level of nitrogen and phosphorus uptake and
removal may be achieved. Restoring a straightened
ditch configuration to a natural and, to varying extent,
sinuous stream channel slows water flow and increases
the interaction with vegetation in the adjacent restored
floodplain, thus facilitating further nutrient uptake and
sediment trapping. Wildlife benefits from both wetland
and stream restoration actions include enhancement
of habitats for feeding, nesting, reproduction, loafing/
resting and protection from predators.
An objective of creating wetlands on the Haines Farm
and similar sites elsewhere is that they may function
as buffers by filtering nutrients and other paniculate
matter that would otherwise be mobilized from the
land directly into waterways during storm events. The
intent is that such filtration will ultimately contribute
to water quality improvement within receiving waters.
Although the results from the exploratory sampling
of the present study do not definitively show how the
Haines wetland cells function with respect to filtering
stormwater runoff, there existed a number of occasions
where inflow-outflow comparisons showed a decrease
in nutrients and suspended solids. While many of these
relations are not statistically significant and therefore
may be just part of the random variability of the system,
it is indicative of these wetlands potentially providing
a nutrient and sediment reduction effect. This apparent
lack of discriminatory ability based on these data is
probably an artifact of the study design, which does not
account for the high variability that is known to occur
in nutrient concentrations over the course of a storm
hydrograph. For example, it is difficult to know if the
higher nutrient concentrations associated with Event
3 are due to seasonal variation in crop management
or simply the timing of sample collection within that
particular storm hydrograph. Furthermore, it also could
be that the overall lack of spatial and temporal patterns
in N concentrations is due to the retention capacity of
the wetlands being simply overwhelmed by the volume
of runoff generated by large storm events. A better
understanding of nutrient and sediment retention in
these wetlands is not possible without implementing a
study which carefully quantifies the flux over multiple
storm events. Although the importance of quantifying
constituent loads was known entering the present study,
there were insufficient resources available to support that
level of effort.
The findings of this exploratory study indicate that
planning for future work may best be focused on
P dynamics. It seems worthwhile to examine why
the outflows of Cells 1 and 3 had TP and SRP that
were consistently and considerably lower than their
respective inflows. Also, it would be useful to identify
any differences in watershed dynamics or wetland cell
configuration that caused Cell 2 to have the appearance
of having no P retention. Although it would be desirable
to better understand N dynamics in the wetland cells, the
N data from this study provide no obvious directional
guidance for future work. It does appear that large
storms may create sufficient runoff and volume to result
in a flow-through condition for at least N and TSS.
However, runoff generated by normal and more frequent
smaller storms which do not overwhelm the retention
capacity of these thin, small-volume lenses of water may
indeed be filtered significantly. This would result in a
reduced impact on water quality in receiving streams,
such as the perennial ditch flowing through the Haines
Farm. It is notable that the Pratt and Kolakowski sites
were not observed to deliver any runoff from the wetland
cells into downstream surface waters even though they
received similar rain events. It was determined during
the study that the watershed area of these two sites
was also much smaller than Haines, thus inadvertently
underscoring the importance of sizing created wetlands
to the size of their respective watershed.
-------
Future research should be a much more focused study
which utilizes automated, flow-triggered sampling
devices, and weirs which would allow the calculation
of flow and loadings. It would need to understand the
filtering dynamics within man-made wetlands associated
with small and large storms alike. This next step should
also include a closer attention to wetland cell/watershed
size, and shallow groundwater input.
Table 1: Water quality variables analyzed for the RARE exploratory man-made wetland monitoring project during
2005 and 2006 at nine sites on the Haines Farm, west of Dover, Delaware. EPA method reference can be
found online at www.epa.gov.
Variable
Method Reference
(EPA)
Reporting Level
Container
Preservation
Holding
Time
Water Column Nutrients
Total Phosphorus
(TP)
Soluble Ortho-
phosphorus (SRP)
Total Nitrogen (TN)
Nitrate+Nitrite N
(N03 + N02)
Ammonia Nitrogen
(NH3)
Total Suspended
Solids (TSS)
pH- Field
EPA365.1M
EPA365.1
SM 4500 NC
EPA353.2
EPA350.1
EPA160.2
EPA150.1
0.005 mg/1 P
0.005 mg/1 P
0.08 mg/1 N
0.005 mg/1 N
0.005 mg/1 N
2 mg/1
0.2 pH units
HPDE 2L
HPDE 2L
HPDE 2L
HPDE 2L
HPDE 2L
HPDE 2L
NA
Cool to <6°C, dark,
digest within 7 days
Filter, Cool to <6°C,
dark
Cool to <6°C, dark,
digest within 7 days
Cool to <6°C, dark,
H2SO4 to pH < 2
Cool to <6°C, dark,
H2SO4 to pH < 2
Cool to <6°C, dark
NA
28 days
48 hours
28 days
28 days
28 days
7 days
NA
Table 2: Comparisons of Inflow vs. Outflow concentrations (mg 1-1) for selected nutrient species and total
suspended solids for the RARE exploratory man-made wetland monitoring project on the Haines Farm,
west of Dover, Delaware during 2005 and 2006. Wetland cell 3 had two inflows. Iron Mine Prong
(Ditch) results based on n = 7 per site, wetland cells based on n = 5 per site. Statistically significant
results at a = 0.05 are bolded. Wilcoxon paired-sample test of the median.
TP
SRP
TN
NO3 + NO2
NH3
TSS
Ditch
S-l vs. S-2
0.500
0.664
0.038
0.277
0.075
0.223
Wetland Cell 1
I vs. O
0.030
0.030
0.500
0.860
0.209
0.208
Wetland Cell 2
lavs. O
0.030
0.030
0.658
0.791
0.606
1.00
Wetland Cell 2
Ibvs. O
0.030
0.053
0.053
0.295
0.140
0.295
Wetland Cell 3
I vs. O
0.500
0.394
0.130
0.705
0.394
0.209
-------
Table 3: Concentration (mg 1-1) comparisons between Inflows and between Outflows for selected nutrient species
and total suspended solids for the RARE exploratory man-made wetland monitoring project on the
Haines Farm, west of Dover, Delaware during 2005 and 2006. Statistically significant results at a = 0.05
are bolded. Friedman's test of the median for block designs.
TP
SRP
TN
NO3 + NO2
NH3
TSS
Inflows
P
0.003
0.048
0.373
0.137
0.696
0.455
Differences
l,2a>2b, 3
l,2a>2b, 3
Outflows
P
0.007
0.007
0.613
0.040
0.247
0.143
Differences
1>2, 3
1>2, 3
1<2, 3
-------
-------
5.0
References
Alsfeld, A.J., J.L. Bowman, A.D. Jacobs. 2005. The
Effects of Construction Amendments on the Biotic
Community of Constructed Depression Wetlands.
University of Delaware, Newark, Delaware 19971.
Castle, M.N., Governor. 1988. State of Delaware
Executive Order #56. Executive Department, Dover,
Delaware.
Delaware Department of Agriculture (DDA). 2007.
What Does the Department of Agriculture Do for You?
Information for Farmers. Publication. Dover, Delaware
19901.
State of Delaware. 2002. Quality Assurance
Management Plan for Laboratory and Field Operations.
DNREC, Environmental Laboratory Section,. 89 Kings
Highway, Dover, DE 19901.
Delaware Department of Natural Resources and
Environmental Control (DNREC). 2004. Drainage and
Water Management: Promoting Drainage, Agriculture
and Ecological Restoration Practices in Delaware.
Brochure. Dover, Delaware 19901.
Delaware Department of Natural Resources and
Environmental Control (DNREC). 2006. State of
Delaware 2006 Watershed Assessment Report (305(b)).
Dover, Delaware 19904.
Holm, S. 1979. A simple sequentially rejective multiple
test procedure. Scandinavian Journal of Statistics
6:65-70.
Maxted, J.R., E.L. Dickey, G.M. Mitchell. 1995. The
Water Quality Effects of Channelization in Coastal Plain
Streams of Delaware. Delaware Department of Natural
Resources and Environmental Control, Division of Water
Resources, Dover, Delaware 19901.
Mayer, P.M., S.K. Reynolds, M.D. McCutchen, and
T.J. Canfield. Riparian buffer width, vegetative cover,
and nitrogen removal effectiveness: A review of current
science and regulations. EPA/600/R-05/118. Cincinnati,
OH, U.S. Environmental Protection Agency, 2006.
Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish
and Wildlife Service, National Wetlands Inventory,
Newton Corner, MA. and Delaware Department of
Natural Resources and Environmental Control, Wetlands
Section, Dover, DE. Cooperative publication. 77pp.
Zar, J.H. 1999. Biostatistical Analysis. Fourth Edition,
Prentice Hall.
-------
-------
6.0
Appendices
Appendix 1 All nutrients and TSS (mg/L), pH in Standard Units. (TP=Total Phosphorous; SRP=Soluble Reactive
Phosphorous; TN=Total Nitrogen; NO3+NO2=Nitrate+Nitrite; NH3=Dissolved Ammonia; TSS=Total
Suspended Solids; ND=No Data; C=Wetland Cell; In=Inflow; Out=Outflow). No samples collected at
any wetland cells on April 6, 2005, and October 24, 2005.
TP
SRP
TN
NO3+NO2
NH3
Date
4/6/05
10/24/05
10/25/05
11/22/05
6/26/06
9/2/06
11/13/06
4/6/05
10/24/05
10/25/05
11/22/05
6/26/06
9/2/06
11/13/06
4/6/05
10/24/05
10/25/05
11/22/05
6/26/06
9/2/06
11/13/06
4/6/05
10/24/05
10/25/05
11/22/05
6/26/06
9/2/06
11/13/06
4/6/05
S-Hn
0.030
0.069
0.400
0.424
0.930
0.516
0.328
0.012
0.029
0.290
0.256
0.087
0.357
0.156
2.55
1.29
1.32
2.14
2.42
1.40
1.45
1.930
0.695
0.722
0.711
0.824
0.389
0.567
0.063
S-2 Out
0.033
0.066
0.411
0.360
0.216
0.531
0.354
0.011
0.027
0.297
0.244
0.187
0.348
0.185
2.05
1.15
1.40
1.58
1.89
1.20
1.46
1.840
0.702
0.645
0.753
0.862
0.364
0.555
0.055
C-Hn
2.013
1.700
4.151
5.363
5.090
1.560
1.720
4.140
3.420
3.680
1.06
1.09
3.10
2.90
1.32
0.499
0.252
0.318
0.101
0.034
C-l
Out
1.144
1.513
3.130
2.414
2.320
0.914
1.680
3.180
2.030
1.910
1.14
1.33
3.12
2.35
1.19
0.383
0.361
0.534
0.237
0.025
C-2a In
2.409
2.337
3.401
2.564
3.630
2.080
2.290
3.200
2.130
2.780
2.05
2.14
2.83
2.58
2.01
1.050
0.533
0.288
0.184
0.030
C-2b In
1.962
1.259
1.033
1.849
1.720
1.740
1.310
0.956
1.120
0.558
3.71
1.97
4.58
4.04
1.64
2.330
0.546
2.160
0.267
0.027
C-2 Out
0.903
0.704
0.553
0.918
0.972
0.670
0.580
0.384
0.728
0.716
2.08
2.11
3.76
2.64
1.03
0.668
0.599
1.920
0.302
0.025
C-3In
1.280
0.645
0.898
1.518
1.010
1.080
0.549
0.741
2.390
0.787
2.43
2.63
2.13
4.77
0.96
1.290
0.517
0.360
0.206
0.018
C-3 Out
0.957
1.016
0.793
1.422
1.110
0.771
1.090
0.649
1.000
0.987
1.55
1.53
3.09
2.07
0.90
0.357
0.583
0.992
0.241
0.017
-------
TSS
pH
Date
10/24/05
10/25/05
11/22/05
6/26/06
9/2/06
11/13/06
4/6/05
10/24/05
10/25/05
11/22/05
6/26/06
9/2/06
11/13/06
4/6/05
10/24/05
10/25/05
11/22/05
6/26/06
9/2/06
11/13/06
S-Hn
0.083
0.070
0.125
0.332
0.021
0.062
o
6
2
12
66
32
15
32
6.03
7.49
7.77
6.68
6.88
6.70
ND
S-2 Out
0.047
0.055
0.005
0.367
0.015
0.046
11
2
10
59
33
13
17
6.09
8.07
7.02
6.71
6.94
6.64
ND
C-Hn
0.051
0.011
0.468
0.093
0.045
23
39
17
13
12
7.28
6.64
6.91
6.89
ND
C-l
Out
0.051
0.026
0.377
0.023
0.033
13
20
29
6
5
7.23
6.70
6.95
6.67
ND
C-2a In
0.174
0.017
0.406
0.021
0.019
34
24
26
7
19
7.07
6.60
6.75
6.77
ND
C-2b In
0.098
0.046
1.010
0.022
0.077
7
9
58
33
41
6.93
6.85
7.03
6.75
ND
C-2 Out
0.075
0.098
0.701
0.020
0.017
5
24
78
10
9
8.05
6.94
7.08
6.70
ND
C-3In
0.171
0.130
0.048
0.146
0.014
9
26
27
39
8
7.61
6.90
6.89
6.69
ND
C-3 Out
0.030
0.025
0.555
0.019
0.020
5
8
33
8
8
6.94
6.84
7.35
ND
-------
PRECIPITATION EVENTS AT HAINES FARM SITE DURING SAMPLING EVENTS
(Sandtown, Delaware -- CSWMC. Station ID - DSND.)
Appendix 2 Weather data from and around the dates of sampling at the Haines site. The Sandtown weather station
is approximately 1.2 miles from the Haines site. Data is from the Delaware Environmental Observation
System webpage (www.deos.udel.edu).
Sample
Date
4/6/2005
10/24/2005
10/25/2005
11/22/2005
6/26/2006
9/2/2006
11/13/2006
Date
4/5/2005
4/6/2005
4/7/2005
4/8/2005
10/22/2005
10/23/2005
10/24/2005
10/25/2005
10/26/2005
11/20/2005
11/21/2005
11/22/2005
11/23/2005
6/23/2006
6/24/2006
6/25/2006
6/26/2006
6/27/2006
8/31/2006
9/1/2006
9/2/2006
9/3/2006
11/11/2006
11/12/2006
11/13/2006
11/14/2006
Max Temp
(°F)
68.1
81.7
74.1
61.3
63.1
60.6
56.3
53
56.5
59.3
52.7
48.8
38.3
85.6
83.8
78.7
78.4
82.3
72.6
67
70.3
73.8
77.3
61.5
61
61.8
Min Temp
(°F)
34.8
48.5
59
42.9
52.1
41.9
40.2
41.5
40.8
31.3
40.1
36.8
30.9
68.9
68.5
68.4
71.8
73.7
65.1
62.2
60.3
57.9
51.3
51.9
53.5
53.9
Avg. Wind
(mph)
2.1
3.5
5
2.9
4.4
3.5
4.7
3.1
3.9
1.3
2.1
5.1
4.4
2
2.3
1.5
2.5
3.8
6
9.7
2.8
0.4
3
3.7
3.3
8.4
Avg. Wind
Dir. (°)
61
59.3
57.8
296.7
201.2
95.3
259.2
56.5
95.3
54.7
333.2
58.6
74.3
45.1
39.7
342.2
10
9.7
251.5
254.8
36
25.9
36.6
277.4
290
95.2
Peak Gust
(mph)
34
34
62.6
32.2
39.4
48.3
48.3
34
50.1
23.3
50.1
55.5
44.7
16.1
14.9
14.3
15.5
27.4
23.2
45.2
47.6
7.6
17.6
27.7
25.3
12.8
Precipitation
(in)
0
0
0.69
1.95
0.96
0
0.74
0.75
0.04
0
1.12
0.84
0
0.15
1.13
1.54
1.1
0.12
0
1.39
0.07
0.01
0
0.48
0.22
0.01
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United States
Environmental Protection
Agency
PRESORTED STANDARD
POSTAGES FEES PAID
EPA
PERMIT NO. G-35
Office of Research and Development (8101R)
Washington, DC 20460
Official Business
Penalty for Private Use
$300
Recycled/Recyclable
Printed with vegetable-based ink on
paper that contains a minimum of
50% post-consumer fiber content
processed chlorine free
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