Editor’s Note: This is the first of what The Chronicle intends to become a series of pieces on the environmental indicators used by the city of Ann Arbor in its State of Our Environment Report. The report is designed as a citizen’s reference tool on environmental issues and as an atlas of the management strategies underway that are intended to conserve and protect our environment. The newest version of the report is organized around 10 Environmental Goals developed by the city’s Environmental Commission and adopted by City Council in 2007.
The first in the series is an introduction to the creeksheds indicator by the city’s environmental coordinator, Matt Naud.
The overall creekshed indicator for the city is yellow (fair) and stable (level arrow). But that overall picture is composed of individual indicators for each of the creeksheds that drain into the Huron River – the central natural feature of Ann Arbor. More than 10 miles of the Huron are located within the city limits.
We assess individual creeksheds, not just the Huron River watershed as whole, because that allows us to focus on exactly the areas that need the most improvement. Seven different creeks within the city of Ann Arbor flow into the Huron: Allen Creek, Fleming Creek, Honey Creek, Malletts Creek, Millers Creek, Swift Run Creek and Traver Creek.
Individual Creeksheds in Ann Arbor
We used monitoring data from the Huron River Watershed Council to develop the individual creekshed indicator ratings.
The Huron River Watershed Council collected and analyzed the original data and provided input on the final indicator ratings. Adrienne Marino, an environmental programs assistant in the city’s Systems Planning Group, developed the indicator pages and maps associated with each creekshed. Each of those pages provides a description of current conditions and links to more detailed fact sheets for each monitoring site within a creekshed.
The indicator icons below link to the respective pages for each creekshed (green is “good,” yellow is “fair,” red is “poor” – the level arrow indicates “stable”):
While the colors correspond to what seem like subjective judgments of “good,” “fair,” and “poor,” those evaluations reflect a quantitative analysis. And the arrows reflect that this analysis has been performed over time for an evaluation of “stable” – neither getting better nor getting worse.
Data on Creeks: The Adopt-a-Stream Program
The long-term monitoring data on the physical and biological stream conditions – which we use for determining the creekshed indicators – are available through the Huron River Watershed Council’s Adopt-a-Stream Program.
The HRWC’s Adopt-a-Stream Program includes more than 400 volunteers, who monitor biological communities, water quality, and stream habitat at 71 river and tributary sites across the Huron River watershed.
What kind of data are gathered? On a single day in April and September of each year, a mix of trained and casual volunteers collect a sample of the benthic macroinvertebrate population at the stream sites. In January, volunteers search for winter stoneflies. During the spring, fall, and winter monitoring, volunteers collect a sample of stream water to measure conductivity. Volunteers also measure the weekly in-stream maximum and minimum temperatures in July and August, and assess the habitat quality of each study site once every few years.
What does this data look like? Here’s an excerpt from the Fleming Creek survey:
Site # Location Insects EPT Sensitive 5-yr trend 9 Fleming Creek: 12 7 2 Stable Botanical Gardens Counts refer to the number of families caught. EPT: Ephemeroptera-Plecoptera-Trichoptera (Mayflies-Stoneflies-Caddisflies)
For the complete Fleming Creek survey report as well as the other Adopt-a-Stream data, visit the HRWC Adopt-a-Stream Monitoring Reports web page.
In more detail, the biological measures include:
- Number of insect families: Insect diversity, as measured by the number of different aquatic insect families, indicates good stream quality. Greater diversity at a site means the water is unpolluted, and there are healthy conditions for a variety of creatures.
- Number of sensitive insect families: Many benthic families living in the Huron River system are sensitive to organic pollution. The presence of these sensitive families at a site indicates that the site, and the upstream portion of it, has high quality.
- Number of EPT families: EPT denotes Ephemeroptera (mayflies), Plecoptera (stoneflies), and Trichoptera (caddisflies). Many mayflies, stoneflies, and caddisflies are sensitive to the quality of a site, and a variety of these families present at a site is another indicator of good water quality.
- Number of winter stonefly families: Stonefly nymphs are extremely sensitive to most pollutants, and they cannot survive if a stream’s dissolved oxygen concentration falls below a critical level. Presence of winter stonefly families is indicative of high water quality.
Physical measures include:
- Habitat assessment score: Based on creekshed-wide measurements of land cover, land use, and percent impervious surface, as well as site-specific habitat measurements including stream bottom composition, water temperature, and width of riparian vegetation. Some indicators of a high quality stream include stable banks with a broad corridor of native vegetation, riffles free of silt deposition, and stable water temperatures.
- Conductivity: An estimate of the total dissolved salts, or ions, in the water. A conductivity measurement of 800 µS is considered normal for the Huron River system.
Analysis of Creek Data
How are Adopt-a-Stream data analyzed? HRWC staff use the Wiley Stream Health Model, an integrative model created for the Huron River system by University of Michigan aquatic ecologist Dr. Mike Wiley. This model uses information about aquatic insect populations, stream habitat, stream temperature, and stream size – the kind of data collected through the Adopt-a-Stream program – to predict the overall health of a stream or river. Specific model inputs include biological and physical habitat measures.
In 2008, HRWC staff re-calibrated the model to the most recent data, and they have used it to make evaluations of stream health in the Huron River watershed.
The scores calculated using the Wiley model reflect the difference between expected versus observed numbers, measured in standard deviations. Adopt-a-Stream monitoring sites are thus rated as poor, fair, good, or excellent based on the Wiley Stream Health Model output. The descriptions corresponding to scores are as follows:
- >1 Excellent. Much better than an average stream of the same size
- >0 Good. Slightly better than an average stream of the same size
- <0 Fair. Slightly worse than an average stream of the same size
- <-1 Poor. Much worse than an average stream of the same size
So who decides what the overall indicator icon should look like – where we are now and where we are going? For the most part, it is the city’s environmental commission, and specifically the State of Our Environment committee, that makes that determination. That committee meets monthly to review the indicators, update the data, and decide on what new indicators can be developed to help reflect our progress (or lack thereof) toward our environmental goals.
The city’s environmental commission also makes decisions about where indicators fit within the city’s 10 environmental goals. For example, the creekshed indicator is a part of the Viable Ecosystems Goal, not the Clean Water Goal. While many of the indicators could fit under more than one of the city’s environmental goals, the environmental commission made a decision to place each indicator under just one goal to simplify the presentation.
Paths to Contribution
One of the goals of this series is to present some information about who’s already working on improving indicator scores and to suggest some specific ways members of the community can contribute to achieving the city’s environmental goals. All water resources planning initiatives by the city of Ann Arbor are summarized on the city’s website.
For Allen Creek specifically, the Allen Creek Stormwater Initiative is a planning group that includes Ann Arbor Public Schools, University of Michigan, Allen Creek Watershed Group, Allen Creek Greenway Conservancy, Friends of West Park, the Huron River Watershed Council, and Peter Allen & Associates.
A website created as part of the Millers Creek Watershed Improvement Plan, funded by Pfizer Global Research and Development, summarizes and organizes activities for Millers Creek. One example is the Millers Creek Film Festival, which has an entry deadline of Feb. 2, 2010 – winning entries will be shown at the festival on March 19, 2010 on the big screen at the Michigan Theater.
And for all creeksheds, the HRWC Adopt-a-Stream program is a way for people to actually get out into the environment and lend a hand with data collection.
The purpose of sharing this indicator through The Chronicle is to share the State of Our Environment Report with the community and hear what you think. As the city’s environmental coordinator, I will be following any comments readers leave here.
Readers who’d prefer to send an email can use MNaud [at] a2gov.org. An easy chance for an in-person chat would be when the city’s environmental commission meets – the fourth Thursday of each month at 7 p.m. in the city council chambers at at city hall. Because of the Thanksgiving holiday, the commission’s next meeting is on Thursday, Dec. 3.