Program Overview

The Middle Huron Chemistry and Flow Monitoring Program, formerly the Water Quality Monitoring Program, was developed in 2002 as a response to community interest in increasing available data on nutrient contributions to the middle section of the Huron River. The data are intended to lead to a better understanding of pollution contributions from non-point sources in the Middle Huron and, in turn, help the local municipalities focus and track pollution reduction efforts as they strive to meet the phosphorus TMDL for Ford and Belleville lakes.


Results Summary

The following general conclusions can be drawn from the analysis of the data collected under the Middle Huron Chemistry and Flow Monitoring Program from 2002 through 2018:

  • Total Phosphorus: In isolation, Total Phosphorus (TP) concentrations show no trend throughout the Middle Huron. However, after accounting for stream flow, there is a significant annual decrease in concentrations. Also, since 2013, concentrations during baseflow conditions at most sites show declining trends in TP and median concentrations are below the TMDL target.
  • Total Suspended Solids (TSS): Mean concentrations of Total Suspended Solids across the Middle Huron are well below sample standards. A few sites, namely Malletts Creek and Swift Run, occasionally exceed the TSS standard during storms. Erosion may also drive phosphorus concentration in these two creeks.
  • Bacteria (E. coli): The data collected on E. coli thus far indicate that all sites except three regularly exceed state standards. However, long-term trends for E. coli in the Middle Huron are steadily declining at most sites.
  • Dissolved Oxygen: All eleven sites had average values for dissolved oxygen that are within the normal range for Michigan surface waters.  Only two measures at separate sites were below this standard.
  • Conductivity: Six of the eleven sites had average conductivity values that exceed the accepted limits. Most of these were the urban sites. This needs investigation to determine the element driving high conductivity levels.
  • pH: In 2018, all eleven sites had measured pH values that are within the expected range for Michigan surface waters.

For additional information these parameters and data, please see below.


Data are collected from stream and river locations that facilitate the establishment of relationships between land cover and ecological stream health. The locations are selected based on their use by the Michigan Department of Environmental Quality, the HRWC Adopt-A-Stream volunteer stream monitoring program, likelihood of significant sub-watershed phosphorus loading based on modeling, and capturing the range of sub-watershed and upstream conditions.

The program monitors annually during the growing season at eleven long-term sites throughout the Middle Huron. Long-term sites help HRWC to determine changing conditions over time. Since 2010, HRWC also monitors at investigative sites located upstream of selected long-term sites.  Investigative sites provide useful data to gain a better understanding of upstream conditions regarding pollutant sources and are usually only sampled for one monitoring season.

Chemistry and Flow Monitoring was conducted in 2018 at three Huron River sites and thirteen tributary sites, which represent a mix of land uses and communities. During the 2018 monitoring season, five of the sixteen monitoring sites were investigative sites. For more information about the sites, please see the map below. Orange and purple sites indicate investigative sites, with green markers reflecting long-term sites.

Middle Huron Chemistry and Flow Monitoring Sites

Total Phosphorus (TP)

Phosphorus is an essential nutrient for all aquatic plants.  It is needed for plant growth and many metabolic reactions in plants and animals. In southern Michigan, phosphorus is typically the growth-limiting factor in fresh water systems.  That is, if all the phosphorus present is used, then plant growth will cease no matter how much nitrogen is available.  Total Phosphorus (TP) is a measure of all forms of phosphorus present in a water sample, and is the primary indicator of overnutrification in the middle Huron River watershed.  The typical background level of TP for a Michigan river is 0.03 mg/L or ppm.  The TMDL established for Ford and Belleville Lakes sets goals of 0.05 mg/L at Ford Lake and 0.03 mg/L at Belleville Lake.

Further, phosphorus is the main parameter of concern in eutrophic lake and stream systems for its role in producing blue-green algae.  Phosphorus enters surface waters from point sources of pollution, such as wastewater treatment plants, and nonpoint sources of pollution, including natural, animal and human sources.  Excessive concentrations of this element can quickly lead to extensive growth of aquatic plants and algae.  Abundant algae and plant growth can lead to depletion of dissolved oxygen in the water, and, in turn, adversely affect aquatic animal populations and cause fish kills.  This nuisance algal and plant growth interferes with recreation and aesthetic enjoyment by reducing water clarity, tangling boat motors, and creating unpleasant swimming conditions, foul odors, and blooms of toxic and nontoxic organisms.

Total Suspended Solids (TSS)

Total suspended solids include all particles suspended in water which will not pass through a filter. As levels of TSS increase in water, water temperature increases while levels of dissolved oxygen decrease. Fish and aquatic insect species are very sensitive to these changes which can lead to a loss of diversity of aquatic life. While Michigan’s Water Quality Standards do not contain numerical limits for TSS, a narrative standard requires that waters not have any of these physical properties: turbidity; unnatural color; oil films; floating solids; foam; settleable solids; suspended solids; and deposits. Water with a TSS concentration <20 mg/L (ppm) is considered clear. Water with levels between 40 and 80 mg/L tends to appear cloudy, and water with concentrations over 150 mg/L usually appears muddy. In streams that have shown impairments to aquatic life due to sedimentation, TSS is used as a surrogate measure for Total Maximum Daily Load (TMDL) regulation, since large amounts of sediment can bury potential habitat for aquatic macroinvertebrates.  This is the case for Malletts Creek and Swift Run TMDLs. Those evaluations set the following targets for TSS:

  • Optimum = < 25 mg/l
  • Good to Moderate = >25 to 80 mg/l
  • Less than moderate = >80 to 400 mg/l
  • Poor = >400 mg/l

Suspended solids may originate from point sources such as sanitary wastewater and industrial wastewater, but most tends to originate from nonpoint sources such as soil erosion from construction sites, urban/suburban sites, agriculture and exposed stream or river banks.

Sediment-phosphorus relationship

Since phosphorus binds to soil particles, it is important to try and understand whether the phosphorus in the streams is coming along with sediment, through erosive processes or not.  To do this, one can examine each TP concentration with its corresponding TSS concentration. If they are well correlated, then there is some evidence that the phosphorus in the stream originated via erosion. If not, the phosphorus may be moving through the system in dissolved form, unbound to sediment particles.

Bacteria (E. coli)

Escherichia coli (E. coli) counts are measured from water samples as a broad indicator of the presence of pathogens found in the digestive tracts of warm-blooded animals. Their presence may indicate the presence of sewage or wastewater, but high counts can also result from other animal sources. These generalized bacterial counts are not specific enough to be directly indicative of health risks.  However, consistently high levels serve as a warning of potential health risks and warrant further investigation to determine the source of bacterial outbreaks.  The State of Michigan water quality standard for  partial body contact is a monthly average of 130 counts per 100ml of water, while a single sampling event for waters protected for full body contact is <300 E. coli counts per 100 ml of water.  Several reaches in the middle Huron are on the state’s list of impaired waters due to bacterial contamination, including Honey Creek, and drainages to and including the Huron River between Argo and Geddes Dams.

Dissolved Oxygen (DO)

Most aquatic plants and animals require a certain level of oxygen dissolved in the water for survival. Dissolved oxygen (DO) is a measure of the amount of gaseous oxygen (O2) in the water, which enters water from the atmosphere via aeration or as a waste product of plant photosynthesis. DO levels drop to very low levels in warm, stagnant water, whereas fast-flowing, cooler water generally has high concentrations of DO. Some forms of pollution can also provide conditions that impact DO levels.  For example, excess nutrients such as phosphorus and nitrogen can result in reductions in DO levels, which can be detrimental to certain species of aquatic insects. Normal DO values in Michigan waters ranges between 5 to 15 mg/L.  The statewide minimum water quality standard is 5 mg/L.  However, concentrations change throughout the day and night due to air and water temperature changes, photosynthesis, respiration and decomposition.


pH provides information about the hydrogen ion (H+) concentration in the water.  pH is measured on a logarithmic scale that ranges from 0-14, with 7 being a neutral value. Solutions with a pH less than 7 are considered acidic and solutions above 7 are considered basic.  Organisms that live in rivers and streams can survive only in a limited range of pH values. Michigan Water Quality Standards require pH values to be within the range of 6.5 to 9 for all waters of the state. In Michigan surface waters, most pH values range between 7.6 and 8.0.  The pH of rivers and streams may fluctuate due to natural events, but inputs due to human activities can also cause ‘unnatural’ fluctuations in pH.


Water temperature dictates what aquatic life will inhabit waterways and controls the dissolved oxygen content of water (as the temperature of water increases, the concentration of dissolved oxygen content decreases). It also influences the rate of both chemical and biological reactions.


Conductivity is a measure of the ability of water to pass an electrical current, and is a general measure of water quality. It indicates the presence of inorganic dissolved solids, such as sulfates, nitrates, phosphates, and salts. Conductivity is affected by temperature: the warmer the water, the higher the conductivity. Conductivity in surface waters is affected primarily by the geology of the area through which the water flows. In Michigan, values for a healthy river or stream habitat range between 100 and 800 µS/cm.  Low values are characteristic of oligotrophic (low nutrient) lake waters, while values above 800 µS/cm are characteristic of eutrophic (high nutrient) lake waters where plants are in abundance. There are a number of potential sources of minerals and some natural variation, but consistent results above 800 µS would be unexpected from natural sources.  Anthropogenic sources can include winter road salts, fertilizers, and drinking water softeners.

Nitrogen (Nitrate and Nitrite) 

Measurements of Total Nitrogen (TN) yield information comparable to concentrations of Total Phosphorus. However, the laboratory used for the program does not measure TN, so nitrate and nitrite were measured in lieu of TN.

Nitrate (NO3) occurs naturally in both ground and surface waters, and is the most common form of dissolved nitrogen. Natural levels of nitrate in surface water can come from precipitation and runoff, and is not considered a problem at low levels. Streams and lakes in southeastern Michigan are typically limited by phosphorus levels rather than nitrogen, though the overall productivity of a waterbody (i.e. the amount of plant life at any given time) is controlled by the balance of these nutrients. At high concentrations (at or above 1-2 mg/L), nitrate can contribute to eutrophication that decreases dissolved oxygen levels and threatens aquatic plant and animal organisms. High levels of nitrate in surface waters often are related to human activities. Overfertilization of lawns and crops, failing septic and sewage systems, and animal waste inputs contribute to elevated levels of nitrate. A typical value of nitrate for Michigan rivers is 0.5 mg/L, although lower nutrient water has nitrate concentrations ranging from 0.01 to 0.1 mg/L.

Nitrite (NO2) is the form of nitrogen that sometimes occurs as a transition compound in the conversion of ammonia (NH4) to nitrate.  Unlike nitrate (NO3), nitrites are short lived in aqueous systems, so they are often found at very low levels, if at all.  However, prolonged exposure to high levels of nitrite can produce a serious condition in fish called “brown blood disease”, as it blocks the blood’s ability to carry oxygen resulting in fish kills.

Water Velocity/Flow

Measuring water velocity at the long-term monitoring sites, along with collecting water samples that are analyzed for nutrient concentration, allows for calculating the “load” of a particular nutrient for a specific moment in time. A “load” is a measure of the amount of a substance entering a water body, usually expressed as pounds per year. Concentration, when coupled with stream discharge, can be used to estimate the export rates of phosphorus (or other nutrients) for the sub-watershed, and to estimate the loading rates of phosphorus in receiving waters.

The procedures used in this monitoring program have been reviewed and approved by the Michigan Department of Environment, Great Lakes, and Energy (EGLE). Complete procedures are documented thoroughly in the program’s Quality Assurance Project Plan (QAPP). The QAPP was originally developed at the beginning of the program in 2003, and revised and approved by EGLE in 2008 and again revised and approved in 2010. The following is a summary of those methods and procedures.

Stream monitoring was conducted twice monthly from April through September at the designated monitoring sites described above. The volunteer monitoring teams travel to sites and first complete a field datasheet that documents the location, date, time, team members and weather conditions for the current and previous days. The field datasheet also is used to record information about the water samples and the water quality measurement results. If stream flow was also measured during a field outing, a separate stream flow datasheet was filled out to record that activity and velocity measurements. Upon completion of the fieldwork, the monitoring team delivered water samples to the Ann Arbor Water Treatment Plant Laboratory.

Sample Collection Methodology

Collection of water samples was completed first at each site to minimize the disturbance of the stream substrate, which could artificially raise the amount of suspended matter in the water column. For all samples, the team member followed the same “grab” sampling protocol in accordance with the method prescribed in the 1994 EGLE field procedures manual for wadeable streams.

In-stream samples were collected upstream and at arm’s length from where the team member was standing. Where stream depth permitted, water was taken from the middle of the water column and in the middle of the stream cross-section. Exceptions to this method occurred at the Hudson Mills Huron River site where samples were collected fifteen feet from water’s edge. The bottles were rinsed three times with stream water prior to taking the baseline sample. Samples were labeled and placed in a cooler with ice packs until they were delivered to the laboratory for analysis.

Baseline samples were collected to measure Total Phosphorus (TP), Total Suspended Solids (TSS), Nitrites (NO2), Nitrates (NO3) and E. coli. HDPE plastic bottles were used for TP, TSS and NO2+NO3 samples. If TP samples could not be analyzed within the method-specified holding period after delivery to the lab, they were treated with preservative.

In-Stream Chemistry Monitoring Methodology

Six water quality chemistry parameters were routinely measured at all sites. Water quality measurements for water temperature, dissolved oxygen, conductivity, total dissolved solids, pH, and chloride were made using a YSI Professional Plus (Pro Plus) multi-meter.  For all measurements, the multi-probe instrument was placed in the water at the appropriate submerged level at arm’s length distance and upstream from the team member. The results were read from the digital displays and recorded on the field data sheet.

Flow Monitoring Methodology

Water velocity was measured directly in the stream after water samples were collected and water quality testing was completed. Flow was measured at each long-term site by team members across a range of measured water levels. Where stream discharge instrumentation or a water level gage was in place, discharge measurements can be charted against water level to establish a “rating curve.”  Once established, the rating curves were used to estimate discharge from water level observations. USGS water-level sensors are located at the Malletts Creek and Mill Creek sites, and a similar sensor maintained by the City of Ann Arbor was placed at Allens Creek in 2007.

Total Phosphorus (TP)

A broad examination of total phosphorus concentrations across all long-term sites in the Middle Huron shows that concentration ranges vary quite a bit year to year. The chart shows that, each season, the bulk of the concentrations range between 0.03 mg/l and 0.1 mg/l, with a few samples exceeding this range by a considerable margin (concentrations highlighted as red stars). These few high concentrations tend to drive the mean concentration of the season to be higher than the median. Over the years, the median concentration declined until reaching a low point in 2009 when it was below the TMDL target at 0.043 mg/l (mean TP=0.052 mg/l). TP concentrations then returned to higher levels through 2014 (median=0.070 mg/l, mean=0.085 mg/l). Median seasonal TP concentrations then decreased again through the current year’s median of 0.041 mg/l (mean=0.075 mg/l), once again below the TMDL target for Ford Lake.

There is no discernable trend in either the mean or median TP concentrations. However, the median for the last three years was below the TMDL target. The few extreme concentrations each season clearly push up the annual mean values. Typically, these high concentrations are measured during or following rain storms. As such, stormwater runoff is still a major pathway of overall phosphorus loading to the middle Huron system.


As shown in this chart, the vast majority of samples from long-term sites in the middle Huron River watershed had TSS concentrations below the target threshold. The mean TSS concentration across all sites for 2018 was 25 mg/l with a median of 6 mg/l, so most samples are quite clear of sediments throughout the watershed. The 2018 figures are also consistent with past years. With such low levels of TSS, trends are not important, however, it appears that TSS concentrations are decreasing even further at a few sites, including both river sites, Mill Creek and Allens Creek.

Sediment-phosphorus relationship

The tributaries in the middle Huron watershed have a wide range of sediment-phosphorus relationships. At the high end, Malletts Creek (R2=0.72) and Swift Run (R2=0.48) both have strong TSS-TP relationships. These neighboring streams are both impaired for sedimentation and both appear to transport phosphorus from streambank or channel erosion. Most other streams have TSS-TP correlations that are in the 0.20-0.40 range. In these creeks, high TSS values are consistent with high TP concentrations, but at the low TSS end, the TP concentrations are more variable. A few other tributaries (i.e. Traver and Millers) and the river sites show very little relationship between TSS and TP. In these watersheds, the phosphorus is likely entering the surface water in dissolved form through surface runoff or groundwater.

Additional monitoring parameter reports to come!

Screenshot of Infostream at Malletts Creek

Visit HRWC’s interactive data viewing feature, Infostream, for more information!

Total Phosphorus (TP)

Looking at individual river and tributary sites can give one an idea of the potential sources of phosphorus. It is more instructive to examine the results by individual tributary site, since sample results are more representative of tributary watersheds than the Middle Huron watershed as a whole. This graph shows TP concentrations for each long-term middle Huron site over the entire range of sampling (2003-18). At the top and bottom of the system, the two river sites show that phosphorus levels increase from well below the TMDL target to slightly above it. In fact, concentrations at the N. Territorial Rd. site have decreased significantly. Phosphorus concentrations at the Michigan Avenue site have also decreased on average, though not as strongly.

In the upper part of the watershed, monitoring stations in Mill, Boyden and Honey Creeks all tell different stories. Mill Creek is the largest tributary in the middle Huron, and has the greatest amount of agricultural land use. Concentrations within its watershed have varied considerably, and have decreased over the last three years. Concentrations in Boyden and Honey Creeks have steadily decreased since 2014. TP concentrations in the urban tributaries are generally higher. TP concentrations in Allens Creek and Traver Creek were high and relatively stable year to year until 2014, when they seemed to decrease somewhat dramatically. This was not the case for the other creeks (Millers, Malletts, Swift Run, and Fleming). However, when concentrations taken during or following storms are removed, the same decrease from 2014 levels is observed. Again, it appears that in urban streams, baseflow concentrations may have decreased through the current year, but concentrations during runoff events are still high, which, in turn, may drive overall loading (see section on phosphorus loads).


Storms do tend to generate turbid runoff at some locations, evidenced by the number of samples over the 80 mg/l threshold. In 2018, at least one sample exceeded the 80 mg/l threshold at Honey, Traver, Millers, Malletts and Swift Run Creeks. All except Honey Creek are urbanized tributaries. Swift Run generated a particularly high TSS sample at 930 mg/l following a storm on September 1. On the same date, a TSS of 493 mg/l was recorded at Malletts Creek. Both are listed as impaired for altered hydrology/sedimentation and appear to continue to exhibit erosion issues during or following storms.

Additional monitoring parameter reports to come!

Visit HRWC’s interactive data viewing feature, Infostream, for more information!

Funding Partners & Governments

The Middle Huron Chemistry and Flow Monitoring Program is a project of the Middle Huron Partners. The Partnership is a voluntary watershed-based group of businesses, academic institutions, and local, county and state governments working since 1996 to prevent pollution in the middle Huron River Watershed and meet federal water quality standards for Ford and Belleville lakes. Member governments and agencies include:

Ann Arbor Charter Township
Ann Arbor Public Schools
Barton Hills Village
City of Ann Arbor
City of Belleville
City of Chelsea
City of Dexter
City of Ypsilanti
Northfield Township
Pittsfield Charter Township
Scio Township
Superior Charter Township
University of Michigan – Environment, Health & Safety
Washtenaw County Road Commission
Washtenaw County Water Resources Commissioner
Ypsilanti Charter Township
VA Ann Arbor Healthcare System

Partners and Volunteers

The strength and breadth of the Middle Huron Chemistry and Flow Monitoring Program is made possible by the generous time and effort provided by the over 60 annual volunteers. The Middle Huron Partners and the Huron River Watershed Council would like to sincerely thank the volunteers and leaders for their dedication to the program.

The Middle Huron Partners would also like to thank the City of Ann Arbor Water Treatment Plant Laboratory for providing water sample processing and analysis.

For additional information on the Chemistry and Flow Monitoring Program and results, please contact Ric Lawson at

To become a volunteer in the program, please visit