Office of Research and Development

National Risk Management Research Laboratory, Ada, Oklahoma 74820

Effectiveness of Restored 

Wetlands for the Treatment of 

Agricultural Runoff

EPA 600/R-08/055 | January 2008 | www.epa.gov/ada

Office of Research and Development

National Risk Management Research Laboratory, Ada, Oklahoma 74820

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
ii

Notice

The U.S. Environmental Protection Agency through its Office of Research 

and Development managed the research described here under EPA Cooperative 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 administrative review and has been approved for publication as an EPA document. 

Mention of trade names or commercial products does not constitute endorsement 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 project 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
iii

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. 

Stephen G. Schmelling, Director

 Ground Water and Ecosystems Restoration Division

National Risk Management Research Laboratory

v

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

vii

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

ix

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

xi

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.

xiii

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 l-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 l-1 were as follows: TSS (5 – 78), TN (0.90 – 3.76), NO3 + NO2 (0.017 – 1.92), NH3 (0.017 
xiv

– 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.
1

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: 
2

• 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 ecologicallyfocused 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 microtopography (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. A D-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 overarching goal of stream corridor restoration projects is to restore highly disturbed and/or degraded streams and their 

surrounding riparian areas to natural, stable stream channels with high ecological functionality. Specific objectives include: 1) restoration of degraded stream channels 

to a more natural morphology; 2) re-establishment of 
3

biological diversity; 3) reduction in surface water pollutants; 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. 

5

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 1a-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 1c). 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 1c). These sites, S-1 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 1c). 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. 
6

Figure 1a. 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 1b. 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).
7

Figure 1c. 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 α = 0.05.

Two major factors expected to affect variable 

concentrations included sampling event and sampling 

site. Their effects were tested using a mixed model TwoWay 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 α 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-1 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. 
 
9

Overall Concentration Observations

Among all four wetland inflows and across all five storm 

sampling events, ranges for constituents in mg l-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 l-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). 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 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 

for TP. 

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. 

3.0

Results
10

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 (SRP) 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.
11

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.
12

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.
13

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 particulate 

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. 
14

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) EPA365.1 M 0.005 mg/l P HPDE 2L Cool to ≤6°C, dark, digest within 7 days 28 days 

Soluble Orthophosphorus (SRP) EPA365.1 0.005 mg/l P HPDE 2L Filter, Cool to ≤6°C, 

dark 48 hours 

Total Nitrogen (TN) SM 4500 NC 0.08 mg/l N HPDE 2L Cool to ≤6°C, dark, 

digest within 7 days 28 days 

Nitrate+Nitrite N 

(NO3 + NO2) EPA353.2 0.005 mg/l N HPDE 2L Cool to ≤6°C, dark, H2SO4 to pH < 2 28 days

Ammonia Nitrogen 

(NH3) EPA350.1 0.005 mg/l N HPDE 2L Cool to ≤6°C, dark, H2SO4 to pH < 2 28 days 

Total Suspended 

Solids (TSS) EPA160.2 2 mg/l HPDE 2L Cool to ≤6°C, dark 7 days 

pH – Field EPA150.1 0.2 pH units NA NA NA

Table 2: Comparisons of Inflow vs. Outflow concentrations (mg l-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 α = 0.05 are bolded. Wilcoxon paired-sample test of the median. 

Ditch

S-1 vs. S-2

Wetland Cell 1

I vs. O

Wetland Cell 2

Ia vs. O

Wetland Cell 2

Ib vs. O

Wetland Cell 3

I vs. O

TP 0.500 0.030 0.030 0.030 0.500

SRP 0.664 0.030 0.030 0.053 0.394

TN 0.038 0.500 0.658 0.053 0.130

NO3 + NO2 0.277 0.860 0.791 0.295 0.705

NH3 0.075 0.209 0.606 0.140 0.394

TSS 0.223 0.208 1.00 0.295 0.209
15

Table 3: Concentration (mg l-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 α = 0.05 

are bolded. Friedman’s test of the median for block designs. 

Inflows Outflows

P Differences P Differences

TP 0.003 1, 2a > 2b, 3 0.007 1 > 2, 3

SRP 0.048 1, 2a > 2b, 3 0.007 1 > 2, 3

TN 0.373 0.613

NO3 + NO2 0.137 0.040 1 < 2, 3

NH3 0.696 0.247

TSS 0.455 0.143

17

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.

19

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.

Date S-1 In S-2 Out C-1 In C-1 

Out C-2a In C-2b In C-2 Out C-3 In C-3 Out

TP 4/6/05 0.030 0.033

10/24/05 0.069 0.066

10/25/05 0.400 0.411 2.013 1.144 2.409 1.962 0.903 1.280 0.957

11/22/05 0.424 0.360 1.700 1.513 2.337 1.259 0.704 0.645 1.016

6/26/06 0.930 0.216 4.151 3.130 3.401 1.033 0.553 0.898 0.793

9/2/06 0.516 0.531 5.363 2.414 2.564 1.849 0.918 1.518 1.422

11/13/06 0.328 0.354 5.090 2.320 3.630 1.720 0.972 1.010 1.110

SRP 4/6/05 0.012 0.011

10/24/05 0.029 0.027

10/25/05 0.290 0.297 1.560 0.914 2.080 1.740 0.670 1.080 0.771

11/22/05 0.256 0.244 1.720 1.680 2.290 1.310 0.580 0.549 1.090

6/26/06 0.087 0.187 4.140 3.180 3.200 0.956 0.384 0.741 0.649

9/2/06 0.357 0.348 3.420 2.030 2.130 1.120 0.728 2.390 1.000

11/13/06 0.156 0.185 3.680 1.910 2.780 0.558 0.716 0.787 0.987

TN 4/6/05 2.55 2.05

10/24/05 1.29 1.15

10/25/05 1.32 1.40 1.06 1.14 2.05 3.71 2.08 2.43 1.55

11/22/05 2.14 1.58 1.09 1.33 2.14 1.97 2.11 2.63 1.53

6/26/06 2.42 1.89 3.10 3.12 2.83 4.58 3.76 2.13 3.09

9/2/06 1.40 1.20 2.90 2.35 2.58 4.04 2.64 4.77 2.07

11/13/06 1.45 1.46 1.32 1.19 2.01 1.64 1.03 0.96 0.90

NO3+NO2 4/6/05 1.930 1.840

10/24/05 0.695 0.702

10/25/05 0.722 0.645 0.499 0.383 1.050 2.330 0.668 1.290 0.357

11/22/05 0.711 0.753 0.252 0.361 0.533 0.546 0.599 0.517 0.583

6/26/06 0.824 0.862 0.318 0.534 0.288 2.160 1.920 0.360 0.992

9/2/06 0.389 0.364 0.101 0.237 0.184 0.267 0.302 0.206 0.241

11/13/06 0.567 0.555 0.034 0.025 0.030 0.027 0.025 0.018 0.017

NH3 4/6/05 0.063 0.055
20

Date S-1 In S-2 Out C-1 In C-1 

Out C-2a In C-2b In C-2 Out C-3 In C-3 Out

10/24/05 0.083 0.047

10/25/05 0.070 0.055 0.051 0.051 0.174 0.098 0.075 0.171 0.030

11/22/05 0.125 0.005 0.011 0.026 0.017 0.046 0.098 0.130 0.025

6/26/06 0.332 0.367 0.468 0.377 0.406 1.010 0.701 0.048 0.555

9/2/06 0.021 0.015 0.093 0.023 0.021 0.022 0.020 0.146 0.019

11/13/06 0.062 0.046 0.045 0.033 0.019 0.077 0.017 0.014 0.020

TSS 4/6/05 3 11

10/24/05 2 2

10/25/05 12 10 23 13 34 7 5 9 5

11/22/05 66 59 39 20 24 9 24 26 8

6/26/06 32 33 17 29 26 58 78 27 33

9/2/06 15 13 13 6 7 33 10 39 8

11/13/06 32 17 12 5 19 41 9 8 8

pH 4/6/05 6.03 6.09

10/24/05 7.49 8.07

10/25/05 7.77 7.02 7.28 7.23 7.07 6.93 8.05 7.61 6.94

11/22/05 6.68 6.71 6.64 6.70 6.60 6.85 6.94 6.90 6.84

6/26/06 6.88 6.94 6.91 6.95 6.75 7.03 7.08 6.89 7.35

9/2/06 6.70 6.64 6.89 6.67 6.77 6.75 6.70 6.69

11/13/06 ND ND ND ND ND ND ND ND ND
21

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 Date Max Temp (°F)

Min Temp 

(°F)

Avg. Wind 

(mph)

Avg. Wind 

Dir. (°)

Peak Gust 

(mph)

Precipitation 

(in)

4/5/2005 68.1 34.8 2.1 61 34 0

4/6/2005 4/6/2005 81.7 48.5 3.5 59.3 34 0

4/7/2005 74.1 59 5 57.8 62.6 0.69

4/8/2005 61.3 42.9 2.9 296.7 32.2 1.95

10/22/2005 63.1 52.1 4.4 201.2 39.4 0.96

10/23/2005 60.6 41.9 3.5 95.3 48.3 0

10/24/2005 10/24/2005 56.3 40.2 4.7 259.2 48.3 0.74

10/25/2005 10/25/2005 53 41.5 3.1 56.5 34 0.75

10/26/2005 56.5 40.8 3.9 95.3 50.1 0.04

11/20/2005 59.3 31.3 1.3 54.7 23.3 0

11/21/2005 52.7 40.1 2.1 333.2 50.1 1.12

11/22/2005 11/22/2005 48.8 36.8 5.1 58.6 55.5 0.84

11/23/2005 38.3 30.9 4.4 74.3 44.7 0

6/23/2006 85.6 68.9 2 45.1 16.1 0.15

6/24/2006 83.8 68.5 2.3 39.7 14.9 1.13

6/25/2006 78.7 68.4 1.5 342.2 14.3 1.54

6/26/2006 6/26/2006 78.4 71.8 2.5 10 15.5 1.1

6/27/2006 82.3 73.7 3.8 9.7 27.4 0.12

8/31/2006 72.6 65.1 6 251.5 23.2 0

9/1/2006 67 62.2 9.7 254.8 45.2 1.39

9/2/2006 9/2/2006 70.3 60.3 2.8 36 47.6 0.07

9/3/2006 73.8 57.9 0.4 25.9 7.6 0.01

11/11/2006 77.3 51.3 3 36.6 17.6 0

11/12/2006 61.5 51.9 3.7 277.4 27.7 0.48

11/13/2006 11/13/2006 61 53.5 3.3 290 25.3 0.22

11/14/2006 61.8 53.9 8.4 95.2 12.8 0.01

Office of Research and Development (8101R)

Washington, DC 20460

Official Business

Penalty for Private Use

$300

PRESORTED STANDARD

POSTAGE & FEES PAID

EPA

PERMIT NO. G-35