MiCorps currently supports a limited set of methods for monitoring streams and a slightly longer list for lakes. There are many additional parameters that can be measured effectively by volunteers and can provide broader understanding about the status and function of aquatic systems. Many of these parameters, including temperature, water level, and chemistry, were discussed among MiCorps e-mail list subscribers in response to an invitation in the last issue of the MiCorps Monitor newsletter.

In this issue, we would like to spotlight one of these methods: stream flow monitoring.

Most of us who manage or advocate for water resources are aware of the network of flow gaging stations managed by the U.S. Geological Survey (USGS). This valuable system provides real-time data on current water level and flow conditions, and results in an accurate long-term record for each station -- all accessible online (water.usgs.gov). However, the existing network leaves out many streams (and some entire watersheds). Smaller streams and headwaters are particularly underrepresented.

Stream flow data, whether collected by the USGS gaging stations or by volunteers, is valuable for a variety of stream protection and restoration efforts. For example, understanding the variability, or flashiness, of flow in a stream section can help pinpoint causes of streambank erosion, or help explain poor macroinvertebrate or fish communities in stream sections. Stream flow data can also be combined with nutrient sampling results to determine monthly or annual loads of nutrients moving through the system. Excessive loads can contribute to poor overall water quality. Flow data also can directly address questions about the local availability of water for human use.

Statewide legislation regulating large-capacity water withdrawals was passed in 2008 and will soon be fully implemented through regulation. The policy is based upon impacts to surface water flow, specifically the “index flow,” which is essentially August low flow for a stream section. Basically, the law says that if a proposed well or other groundwater withdrawal is likely to reduce the index flow enough to impact the resident fish species, then the withdrawal may be prohibited. Michigan uses a computer model built from existing flow data as a first step in screening proposed withdrawals for possible prohibited impacts. You can see this screening tool yourself at www.miwwat.org.

The existing model is pretty good, but there are many stream sections (and even entire stream systems) for which the index flow that informs the regulations is only a model prediction, since there are no actual flow data for those stream sections. There is clearly a need for additional stream data for confirming and improving the model. Also, the statewide model is only a screening tool. If the screening tool determines that an adverse impact may result from a proposed withdrawal, the next step is a site-specific review of the proposal by the Michigan Department of Environmental Quality (DEQ). DEQ will need good data to make a good decision -- approving or denying the proposed water withdrawal. There is also a public participation process where any interested party can come forward and disagree with the model (or DEQ), and if they can provide sound data in support of their argument, the withdrawal proposal could be denied on that basis.

Due to this renewed interest in stream flow data across Michigan, there is now discussion among involved agencies, stakeholder groups, and the advisory committee to the state legislature about a process to “certify” individuals to collect reliable flow measurements. Such data could be used to improve the screening model or otherwise in the permitting process. Organizations with existing volunteer monitoring programs could be well-positioned to help in this important effort.

Flow monitoring can be as simple as the “orange” method (measuring the average time it takes for a float to travel downstream) or as complicated as establishing a fixed, long-term flow gaging station in cooperation with USGS. Each level offers a trade-off between accuracy, ease of implementation and cost. With relatively low expense in equipment (an accurate water velocity meter can be obtained for $1,000 – $3,000) and some basic training, a volunteer monitoring group can collect good flow information for many years at sites all across a given watershed. For a little more expense, and a fair bit more training, selected sites can be monitored for continuous flow using water level loggers. The effort requires determined volunteer oversight and quality control to generate accurate estimates, but the data can be very useful in determining local management priorities. The Huron River Watershed Council has been using these techniques with volunteers for several years.

Contact Ric Lawson or Paul Steen or send a message to the e-mail list to discuss. Also, let us know if you would like a detailed presentation on this topic at the 2009 MiCorps Conference. For more information on the water withdrawal regulations and model, see the fact sheet at www.emdc.msue.msu.edu, Inventory Number WQ60.

Authors:
Ric Lawson
MiCorps Staff
Huron River Watershed Council

Jo Latimore
Dept. of Fisheries and Wildlife
Michigan State University