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 Frequently Asked Questions
Q1 What is Lake Access?
Q2 Why is this important?
Q3 What is that big yellow thing floating out in the lake?
Q4 Where are the RUSS units located?
Q5 Why did we put the RUSS units where we did?
Q6 Wow, this is pretty interesting, is there anything else I should visit on the site?
Q7 I'm really impressed now, who is doing all this?
Q8 How is my water quality?
Q9 There's some foam blowing up onto my beach, where's it coming from?
Q10 What causes surface scum on a lake?
Q11 Why does the water quality of our lake seem to get worse throughout the summer?
Q12 Why can a lake become green and stinky?

 

Q1 What is Lake Access?
Lake Access is an initiative begun in 1999 to deliver real-time water quality information on Minneapolis metropolitan lakes to the public using advanced sensor technology and the Internet. Beginning in 2001 the project was expanded to include a study of the effects of lawn fertilizer phosphorus on the phosphorus budget of nearby Medicine Lake that suffers from eutrophication due to excessive phosphorus inputs.
Q2 Why is this important?
Communities are becoming increasingly involved in land management decisions that affect their quality of life. Access to information for making informed decisions, however, has been a limiting factor, both in terms of availability and understanding. Our goal is to provide relevant information to citizens on a timely basis.
Q3 What is that big yellow thing floating out in the lakes?
That is a Remote Underwater Sampling Station, or RUSS unit. The RUSS is a sensor system collects water quality information and transmits it back to our web site. RUSS consists of a mobile underwater sensor package connected to floating platform that contains an on-board computer, solar panels and telemetry equipment. We use a cell phone to call the RUSS unit and download data each morning - the units collect data 4 to 6 times per day. You can learn more about RUSS technology here.
Q4 Where are the RUSS units located?
The RUSS units EMPACT01 and EMPACT02 were initially located in West Upper Lake and Halsteds Bay, respectively. Another unit that was acquired for our Water on the Web study was located in nearby Lake Independence. Halsteds Bay, located on the far west end of Lake Minnetonka, receives runoff water from a large watershed of mixed agricultural and urban residential land use. As a result of the nutrient loading from runoff water, the quality of the bay is very poor. The mean summer phosphorus concentration is near 100 ug/L, making the bay highly eutrophic (green) as evidenced by poor water clarity (Secchi depth < 1 m) due to excessive algal growth. West Upper Lake, by comparison, has much better water quality, with a mean phosphorus concentration of ~25 ug/L during the growing season and Secchi depths averaging > 2 m. West Upper Lake receives direct runoff only from the area immediately adjacent to the shoreline and is much deeper than Halsteds Bay. The Lake Independence unit, WOW02, was located in the southern part of the lake and sampled to a depth of 30 ft. In 2001, we moved the unit from the West Upper Lake site to Medicine Lake to provide an intensive set of lake data fro the fertilizer experiment. We also discontinued data collection on Lake Independence and moved the unit to Shagawa Lake in Ely, MN.
Q5 Why did we put the RUSS units where we did?
A1- As good limnologists, we knew that significant algal blooms in eutrophic Halsteds Bay were occasionally triggered by wind mixing of nutrients from below the thermocline during big storms. We wanted to show how this differed from the less productive West Upper Lake basin. This fact becomes important in developing management strategies for improving the water quality of the lake and setting accurate expectations for the results of controlling the runoff of nutrients from the watershed. It would also be necessary to control this in-lake source of nutrients to get short-term (years) results. Medicine Lake was also a good candidate for RUSS technology because previous studies indicated that, as for Halsteds Bay, summer storms could inject large amounts of phosphorus from bottom waters into the upper sunlit zone to fuel obnoxious algal blooms. Beginning in 2002 we will also have a fluorometer on this unit which is a sensor that can detect the chlorophyll in algae and give us a near-continuous record of algal growth.
A2 - We also had to keep the units out of the way of major water skiing routes so they are a bit closer to shore than we might have liked. They all had have permits from the County Sheriff.
Q6 Wow, this is pretty interesting, is there anything else I should visit on the site?
Why, in fact, yes! The Lake Ecology section is a concise guide to the basic physical and chemical factors that control lakes, along with detailed information on lake biology. We also have sections for users of the lake: boaters, swimmers, anglers, as well as a section on current issues and a Take Action section to make it easy for you to get involved or just obtain good information on issues and decisions that being made about your lakes. There's lots of historical data including "grades" for lakes in the area and also a description of the new (2001-2003) lawn fertilizer phosphorus study in the Medicine Lake watershed.
Q7 I'm really impressed now, who is doing all this?
Lake Access is a partnership among Hennepin Parks, the Natural Resources Research Institute, Minnesota Sea Grant, the University of Minnesota-Duluth Department of Education, the Minnehaha Creek Watershed District, the Minnesota Science Museum and Apprise Technologies, Inc. We are funded through a grant from the Environmental Protection Agency's EMPACT program. Also check out our sister project Water on the Web.
Q8 How is my water quality?
  Well, that's one of those tough questions. But we have a place where you can begin to look. Try the Lake Data page to see if your lake is there. If so you'll find all sorts of information about historical and current conditions in your lake and, if we did our job, you should have enough information to determine for yourself if your lake is in good shape or not. If your lake is a Twin Cities metro lake but not listed on the Lake Data page check back. We're making our way through all of the data available and hope to have most metro lakes up soon.
The following questions and answers were adapted from the New Hampshire Department of Environmental Services and from the forthcoming Minnesota Shoreline Management Guide
Q9 There's some foam blowing up onto my beach, where's it coming from?
Most foam observed in lakes and streams is a product of nature; foam is not necessarily an indicator of pollution. Foam is created when the surface tension of water (attraction of surface molecules for each other) is reduced and air is mixed in, forming bubbles. Surface tension can be reduced by both natural organic compounds and by man-made soaps and detergents. Natural organic compounds are released by decomposing aquatic organisms (such as algae or fish) or leached from the soil. In a lake, wind, currents, and boats mix air with the organic compounds present to produce foam. The foam will frequently form parallel streaks in the open water, caused by wind-induced surface currents. It will also collect in large quantities on windward shores, coves, or in eddies. Natural foam has a somewhat earthy fishy aroma. Detergent foam in contrast will have a noticeable perfumey smell.
Q10 What causes surface scum on a lake?
Scum, an oily film, or yellow-green dust on the surface of a lake make it looks contaminated but, in most cases, nothing is wrong. In fact, something natural is probably occurring. An oily film in midsummer is most likely caused by insect cases that were concentrated along the shore by wind after a hatch. Insects can hatch any time from ice-out into September. As the cases decompose, they sometimes give off an oily film. Yellow-green dust floating on the surface in late spring and early summer is pollen from nearby pine trees. In contrast, an algal bloom is green to blue-green, might look soupy, and can form thick surface scum.
Q11 Why does the water quality of our lake seem to get worse throughout the summer?
Many factors, including human activity in the watershed, affect the water quality of a lake. Just as fertilizing a lawn promotes growth, nutrients seeping into a lake cause aquatic plants to grow. Agriculture and communities in the watershed may be inadvertently adding nutrients to the lake. Although lawns and agriculture are not innately harmful, excess fertilizer causes algae to "bloom" which, in turn, decreases light for other plants and animals. Water quality may worsen at the peak of the growing season when sunlight and nutrients are plentiful. Also, erosion and sediments washing in from disturbed shorelines or construction sites bring additional nutrients and muddy the water. Development on a lake shore usually means changes in the shoreline plant community (i.e., cultivated grass replaces bulrush). Nutrients and sediments wash into the water more readily without the natural filtering system.
Q12 Why can a lake become green and stinky?
Stinky green lakes are blooming with algae. Algae are unicellular or small aquatic plants. An algal bloom is a dense concentration of these plants. If a lake has high concentrations of nutrients (especially nitrogen and phosphorus), a few types of algae may be out-competing the many other types of algae, becoming so abundant that the water appears murky. Two common bloom-forming groups of algae are diatoms and blue-green algae. Diatom blooms usually occur in the late spring or early summer, turning the water brown, but not creating surface scums or odors. Blue-green algae blooms create greater problems for lake users. The most obnoxious forms are buoyant during the day and can form thick surface scums, especially on a calm sunny afternoon. This scum may be blown into shallow water making the shoreline appear slick with blue-green paint. Sometimes surface algae are literally shocked by sunlight and die. As they decompose, the odor can be unpleasant and the oxygen in the water is depleted. If enough algae die and the oxygen in the water is consumed faster than the atmosphere can recharge it, hydrogen sulfide, which smells like rotten eggs and is very toxic to fish, builds up in the bottom water. Unionized ammonia can also build up to concentrations toxic to fish and other aquatic organisms.

 

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