A Proposal

Titled

Effectiveness of an in-stream sedimentation pond in reducing the mass of bed sediment,

concentrations and loading of suspended solids, phosphorus, and Escherichia coli in Wolf

Creek, Oregon, OH

By

Matthew Mayher

Submitted as partial fulfillment of the requirements for

the Master of Science degree in Biology (Ecology-track)

The University of Toledo

August 2015

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Purpose Statement

To assess the effectiveness of a recently modified portion of Wolf Creek that includes

floodplains and an instream sedimentation pond, with respect to improvements in water quality.

Introduction

Water quality in the western Lake Erie basin is an ongoing topic of interest since the 1960s due

in part to nuisance algal blooms, poor water clarity, and hypoxic areas. In 1972, the United States

and Canada signed the Great Lakes Water Quality Agreement (GLWQA, 1972) that initiated a

bi-national effort to reduce the loadings of nutrients and the degradation of the Great Lakes. In

that year, the U.S. federal government passed amendments to the Federal Water Pollution

Control Act, to better regulate water pollution and restore and maintain the integrity of the

nation’s waters (FWPCA, 1972), commonly called the Clean Water Act (CWA). Specifically,

the CWA sets standards for inputs to surface waters by point sources that include publicly owned

sewage treatment plants and industrial facilities. As expected, the annual loadings of phosphorus

to Lake Erie (Fraser 1987; Dolan 1993; Rosa 1987) and its tributaries (Richards and Baker,

1993) significantly decreased by the 1980s, which improved water quality (Bertram, 1993;

Makarewicz, 1993). However, harmful algal blooms (HABs) began to occur in the western basin

in the mid-1990s (Conroy and Culver 2005; Budd et al. 2002) and recur annually since that time

(Bridgeman et al., 2010 and 2013).

Lake Erie tributaries, especially the Maumee River, are major contributors of suspended solids

and phosphorus (Heidelberg National Center for Water Quality Research,

http://www.heidelberg.edu/academiclife/distinctive/ncwqr), which promote the growth of HABs

(Rinta-Kanto et al., 2009 and Bridgeman et al., 2012;). Many tributaries are dominated by

agricultural land use; for example, the Maumee River watershed is approximately 17,000 km2

(Moorhead et al., 2008) with agricultural land covering 75% of the area (Baker, 1985). Fertilizer,

animal manure, and/or sludge from wastewater treatment plants applied to agricultural fields are

a source of nutrients for crops. During rain events and snowmelt, phosphorus from these

applications is lost via surface runoff and subsurface drainage tiles that empty into drainage

ditches (Gentry et al., 2007; Kleinman et al., 2011). In cases with animal manure and/or

wastewater sludge, concern exists for the presence of pathogens from the human and animal

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waste in the receiving waters (Abu-Ashour and Lee, 2000; Byappanahalli et al., 2003). In

addition, phosphorus attached to soil may be lost from the fields due to surface runoff, which

may be increased on fields that use tillage (Tiessen et al., 2010).

Local Problem

The Wolf Creek watershed, located in Lucas County, Ohio covers 41.44 km2. The watershed was

originally identified as a proximal source of E. coli to Maumee Bay (Lauber et al., 2003; Francy

et al., 2005). Since 2002, an average of 19 swim advisories were posted at the beach during each

recreational season, which extends from May through August. This led to a series of studies

beginning in 2005 to monitor the loadings of E. coli as well as other pollutants to Maumee Bay.

Estimates of the loadings from July 2007 to July 2008 were: E. coli = 9.19 x 1014 colony forming

units (CFUs), suspended solids (SS) (4747 metric tons (MT)), and total phosphorus (TP) (20

MT) (Dwyer, unpublished data).

Treatment Strategies

To lower the number of swim advisors at MBSP, the Wolf Creek Corridor Restoration Plan was

proposed in 2011 (http://www.tmacog.org/Environment/Wolf_Creek.htm) to treat the creek’s

water. The plan included a constructed wetland and sedimentation pond to improve water

quality. Both strategies are reported to achieve wanted results. Fink and Mitsch (2004) reported a

two year overall reduction in TP concentration of 59% for a restored marsh wetland in Rush

Creek Township, Logan County, OH. Brown et al., (1981) observed a reduction in TP loading of

25-33% over five years for a sedimentation pond in southern Idaho near Snake River.

Dr. Dwyer recently received two grants from the Great Lakes Restoration Initiative administered

by the U.S. Environmental Protection Agency (USEPA) to construct a two-acre sedimentation

pond and a seven-acre treatment wetland within the Wolf Creek watershed (Figure 1). The

sedimentation pond is located on property owned by the city of Oregon, is situated in-stream of

Wolf Creek along with an over-wide floodplain, and is designed to promote settling of SS and

deposition of rolling bed sediment (RBS). The treatment wetland is located downstream of the

sedimentation pond within MBSP and consists of a retention pond hydraulically connected to

Berger Ditch (the downstream section of Wolf Creek) from which water is pumped through a

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gravity-fed, three-terraced wetland where it is treated and discharged to Berger Ditch. Both

stages of the treatment system work concurrently to reduce the loadings of bacteria, sediment,

and nutrients emptying into Maumee Bay.

The sedimentation pond is the focus of this study. It functions to remove RBS, (Figure 2), which

consists of small to large particles that move with the flow of water along the creek bed and may

be a source of nutrients (Jarvie et al., 2005) and bacteria (Byappanahalli et al., 2003). The

sedimentation pond may also promote the settling of SS from the water column (Figure 2). In

addition, previous data indicate that of the SS within Wolf Creek, 42% is sand, 55% is silt, and

3% is clay and that densities of E. coli are highly correlated with SS during the summer (R =

0.76) and fall (R = 0.70) (Dwyer, unpublished data). The purpose of my research is to assess

whether the concentrations and loadings of SS, TP, orthophosphate (OP), and E. coli in Wolf

Creek decrease due to the presence of the sedimentation pond.

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Figure 1. Locations of the in-stream treatment systems within the Wolf Creek watershed. The

star indicates Maumee Bay State Park and the triangle is the location of a USGS gage station.

Image courtesy of the University of Toledo and Hull & Associates, Inc.

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Figure 2. Accumulation of rolling bed sediment and suspended solids into the sedimentation

pond. As water enters the sedimentation pond, particles present in the water column and larger

particles (e.g., sand-sized and greater) that flow along the creek bed will deposit into the pond.

Image courtesy of Ryan Jackwood.

Hypothesis

My hypothesis is that (i) reductions will be observed in the concentrations and loadings of SS,

phosphorus, and E. coli in the water column at the pond’s outlet compared to its inlet during low

flow and seiche events (wind driven reversal of tributary flow) that results in an observable (ii)

accumulation of sediment within the sedimentation pond.

Objectives

Objective 1: Measure the concentrations of E. coli, SS, OP, and TP in the water column at the

inlet and outlet for one year when ice cover is not present, as well as the accumulation of

sediment, E. coli and TP in the sedimentation pond.

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Objective 2: Measure and obtain discharge values for Wolf Creek at the time of sampling to

calculate loadings and loading reductions of E. coli, SS, OP, and TP at the inlet and outlet of the

sedimentation pond on a flow event basis.

Measures of Success

First, I will determine the percent reduction in concentrations and loadings in Wolf Creek

attributed to the sedimentation pond on a flow event basis (i.e. high or storm flow, low flow, and

seiche events). Reductions will be considered a successful outcome. Second, I will compare the

number of beach postings at MBSP for flow event periods, prior to and since the installation of

the sedimentation pond. A decrease in the number of beach closures along with reduced loadings

would indicate that the sedimentation pond contributed to a positive outcome on beach and

nearshore health.

Materials and Methods

Site Description

The Wolf Creek watershed (Hydrologic Unit Code 41000100704, NW Ohio) is 41.44 km2 in

size. Wolf Creek flows northeast through Northwood, Oregon, and Jerusalem Township and

becomes Berger Ditch at North Curtice Road. Berger Ditch enters Lake Erie at a marina near the

public swimming beaches located in MBSP, which are operated by the Ohio Department of

Natural Resources. The sedimentation pond was constructed in the Wolf Creek watershed prior

to the point at which Wolf Creek becomes Berger Ditch at North Curtice and Corduroy Road.

Lucas County, Oregon, Ohio 43616 (41° 39’ 48” N, 83° 22’ 27” W) (Figure 1). Agricultural

fields and land associated with the city of Oregon’s drinking water treatment plant adjoin the

location.

The two main features of the sedimentation pond include floodplains along the banks and a basin

in its center, with an approximate area of 0.85 ha (Figure 3). The floodplains were constructed

1.5 m below the ground surface of the adjoining properties, and extend a maximum of 15.2 m

from the center of the creek to banks on both sides for a total width of 30 m, and are

approximately 282 m in length. The basin is in the northeastern portion of the sedimentation

pond and has a maximum depth of 3 m from the floodplains, a maximum width of 15 m, and a

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maximum length of 146 m. The overall storage capacity of the sedimentation pond is

approximately 6570 m3. The majority of the water entering the sedimentation pond comes from

Wolf Creek and flows in a northeasterly direction; however, there is a small agricultural ditch

that flows directly into its western portion.

Collection of Water Samples

I established a monitoring regime that includes collecting water samples and measuring stream

flow from the main inlet, ditch inlet, and outlet locations of the sedimentation pond (Figure 3).

Water samples are collected at least once per week at these locations with additional sampling

events during high flow situations, such as spring melt and storm events. Samples of water are

collected in Nalgene bottles (500 ml) from the center of the creek at each location, approximately

10 cm below surface. To prevent collection of resuspended RBS from wading when samples are

obtained, I face upstream, extend my arms as far as possible away from my body, and open the

sample bottle beneath the surface of water and quickly close the bottle after the water sample is

collected. During periods when the water level is above a meter, a 7.32 m extendable Nasco

Swing Sampler (Nasco, Fort Atkinson, Wisconsin, USA) is used to collect water samples. Once

collected, samples are immediately placed on ice in a cooler and transported back to the

laboratory for analysis.

Measurement of Discharge

Discharge (volume per time) is determined for the three sampling locations (main inlet, ditch

inlet, and outlet) using the mid-section calculation method described by the USGS (Rantz et al.,

1982a). Briefly, the width of the creek is divided into 10 to 30 sections depending on its width at

the time of sampling; a greater number of sections is used when the creek is wider, such as

following a precipitation event when the stage height increases. It’s worth noting that Rantz et

al., (1982a) recommend using 20 to 30 sections to improve accuracy of the discharge calculation.

At the midpoint within each section, the velocity (m/sec) and depth of the water (surface down to

creek bed) are measured using a top-setting wading rod with a portable flowmeter (Marsh-

McBirney Flo-MateTM). Discharge is then calculated for each midsection by multiplying the

velocity of water measured for the midsection by the area of the midsection; total discharge is

calculated as the summation of all the midsection discharges. I had operating issues with the flow

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meter at times, therefore I developed a stage-discharge rating curve (Rantz et al., 1982b) using

discharge values and stage measurements that I previously documented to estimate loading based

on stage height.

Figure 3. Sedimentation pond located within the Wolf Creek watershed on property owned by

the city of Oregon. Floodplain areas are represented by the gray section, and the pond/basin is

depicted by the large black section. Red dots indicate sediment core sampling locations. Image

courtesy of Hull & Associates, Inc.

Collection of Sediment Cores

Sediment cores are collected on a monthly and event basis (a few days before and after a large

storm) from three locations in the sedimentation pond: near the main inlet, center, and near the

outlet (Figure 3). A small boat is used to reach the desired sampling locations. At each location,

three cores (approximately 30 cm in depth) are collected using a gravity corer (Aquatic Research

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Instruments, 620 Wellington Place). The cores are immediately transported to the laboratory for

analyses. To calculate the amount of accumulated sediment, the height, volume, and weight of

the sediment above the natural clay layer of the sedimentation pond are measured as described in

the calculations section.

Laboratory Analyses

Water Samples

Water samples are analyzed within 6 hrs of the time of collection for E. coli, SS, turbidity, OP,

and TP. Densities of E. coli are enumerated using the membrane filtration method, EPA Method

1603 (USEPA, 2006) and reported as CFU per 100 mL of water. Suspended solids are analyzed

using the vacuum filtration method 2540-D (APHA, 2005) and reported as milligrams of dried

sediment per liter of water (mg/L). Turbidity is analyzed using a portable turbidimeter (Hach

2100p, Loveland, Colo.) with values reported as Nephlometric Turbidity Units (NTU).

Orthophosphate and TP are analyzed in unfiltered water samples using spectrophotometry

following the phosphomolybdenum blue procedure outlined in EPA Method 365.2 (USEPA,

1971), and reported as mg/L. Due to the long analysis time required for TP, water samples are

temporarily stored at 0°C in 125 mL acid washed bottles within a freezer. After a month’s worth

of samples is collected, I analyze the frozen samples.

Sediment Cores

The height of the layer of sediment above the clay layer of the sediment cores is measured then

removed and homogenized in an acid washed, autoclaved container. Twenty (20) g of sediment

are used to enumerate E. coli and 50 g are used to measure the concentration of TP. E. coli are

analyzed immediately (within 24 hrs from the time of collection) using the Colilert Method as

described by Struffolino (2010) and reported as the most probable number (MPN) per g of dried

sediment. It’s worth noting that the membrane filtration method used for analyzing E. coli in

water samples provides comparable results to the Colilert Method (Eckner 1998) without running

the risk of inaccurate numbers due to filter clogging from the sediment. TP is analyzed using the

Lachat Method LG600 (USEPA, 2004) and reported as mg of P per g of dried sediment (mg

P/g). Sediment from the top of the core (recently deposited suspended solids), the middle of the

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bed sediment layer (older deposited suspended solids), and the clay layer (natural soil) are

analyzed for particle size distribution using the laser diffraction method (Punnamaraju, 2012)

Meteorological Data

Precipitation, temperature, and wind speed and direction are obtained from the Toledo Executive

Airport weather station (41°33'55.6"N, 83°28'52.6"W) that is located 14 km south of the

sedimentation pond. These data are obtained for analyses as to correlations between

concentrations and loadings and weather events.

Quality Assurance and Quality Control

To ensure the quality of the laboratory analyses, at least 10% of all samples collected are field

replicates and 10% are used as duplicates for each measured parameter. A field replicate for

water samples is obtained by collecting three samples per location to assess representativeness of

the samples, while a duplicate involves analysis of a water sample twice to assess analyst

precision. In addition, a trip blank that consists of 500 mL of purified water in an empty

sterilized sample bottle is used to assess the cleanliness of the sample containers and

contamination pathways during transport from the field to the laboratory. The equipment used in

this study are calibrated at a frequency suggested by the manufacturer. The data collected are

documented in personal carbon-copy notebooks, on hard copy paper and placed into a binder,

and entered into Excel spreadsheets for electronic storage on personal and laboratory computers.

Statistical Analyses

Statistical analyses are performed using the open-source statistical program R (R Core Team,

2015). Paired t-tests are used to determine whether there is a significant difference (α = 0.05) in

the daily values (i.e. concentrations and loadings) for the analyzed parameters between the inlet

and outlet of the sedimentation pond. Pearson’s correlation coefficients are calculated to examine

the linear relationships between the measured parameters, the deposited bed sediment, and the

meteorological parameters. After determining the percent reduction in concentration and loading

for the measured parameters on a flow event basis, I will apply the reductions to previous years

of data for the Wolf Creek watershed before the sedimentation pond was implemented to assess

its potential impact on the watershed.

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Calculation for Loading Values for Measured Parameters

The estimated daily loading values for E. coli, SS, OP, and TP are calculated using Equation 1:

Load=k∑i=1

n

ci qi ∆ t Equation 1

k1=(1× 103) L

1 m3 ×(8.64 × 104 ) sec

1 day×

(1×10−6 ) kilograms1 mg

=86.4

k 2=(1× 103) L

1 m3 ×(8.64 × 104 ) sec

1 day×

(1×10−9 )metric tons1 mg

=8.64 ×10−2

k3=(1× 106)mL

1m3 × m3

sec× (8.64 ×104)sec

1 day=8.64 × 108

where k is a unit conversion factor to calculate loadings in kilograms (k1), metric tons (k2), and

CFU per day (k3); ci is concentration (mg/L) or density (CFU/100 mL) of sample i; and q i is

discharge (m3/sec) at the time of sample i multiplied by the desired interval of time Δt (i.e, day)

(Meals et al., 2013). When replicate samples (n) are collected at the same time, the mean for the

replicates is used as the concentration (ci).

Calculation for Percent Reduction in Concentrations and Loadings for Measured Parameters by

the Sedimentation Pond

The reduction in the concentrations and loadings for the measured parameters is calculated using

Equation 2:

[((I+D) - O)/(I+D)] x 100 = % Parameter Removed Equation 2

where (I+D) is the mean daily concentration (mg/L or CFUs per 100 mL) or loading (kg, t, or

CFU/d) from the main creek inlet (I) plus the small ditch inlet (D), and O is the mean daily

concentration or loading at the creek outlet. Upon analysis of my data, I will determine whether

the ditch inlet contributes significantly to the system, thus warranting its current inclusion into

the reduction equation.

Calculation for Reduction in Loadings for Measured Parameters by the Sedimentation Pond

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The reduction in the concentrations and loadings for the measured parameters is calculated using

Equation 3:

[(I+D) – O] / 8500 m2 = Parameter Removed Equation 3

where (I+D) is the mean daily concentration (mg/L or CFUs per 100 mL) or loading (kg, t, or

CFU/d) from the main creek inlet (I) plus the small ditch inlet (D), O is the mean daily

concentration or loading at the creek outlet, and the 8500 m2 is the entire sedimentation pond

system area. Upon analysis of my data, I will determine whether the ditch inlet contributes

significantly to the system, thus warranting its current inclusion into the reduction equation.

Calculations for Accumulation of Sediment, Total Phosphorus, and E. coli in the Sedimentation

Pond

In order to calculate the accumulation of sediment in grams per square meter at the bottom of the

pond from the cores, Equation 4 is followed.

(H x D x K1) x (C x K2) = Accumulation (g/m2) Equation 4

K 1=(1×104 ) cm2

1 m2 =1 ×104

K 2=1 g P

(1×103)mg P=1 ×10−3

where H is the height (cm) of sediment measured in the sediment cores (mean of the nine cores

collected during each sampling event), D is the density of the sediment (g/cm3), and K1 is the

conversion factor for square centimeters to square meters of sediment. The accumulation for TP

(g P/m2) and E. coli (MPN/m2) are estimated by first multiplying the respective mean

concentration (C; mg P and MPN per gram of dry sediment) from the nine cores by the estimated

mass of sediment per area and then by the conversion factor (K2) for TP. Accumulation is

expressed in days since the finished construction of the pond on July 18th, 2014 to the present.

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Theoretical Results

Figure 4. A theoretical curve of how efficient the sedimentation pond will be at removal of the measured parameters (i.e. E. coli, SS, OP, and TP) based on discharge.

Based on how the sedimentation pond is designed to function, I expect that as discharge increases, removal efficiency will also increase until a point where the sedimentation pond is overwhelmed at high flows.

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Timeline:

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Task Master Degree Requirements

J J A S O N D J F M A M J J A S O N D J F M A M J J

1 Select Committee2 Plan of Study3 Courses4 Teaching Assisstant5 Proposal6 Advisory Committee7 Thesis8 Thesis Defense9 Apply for Graduation

Research 1 Sediment Core Sampling2 Water Sampling (Weekly)

2014 2015 2016

*Gold cells indicate data will be collected, but not incorporated into results of this study.

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