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 What's New

3/21/05

World Water Day 2005

Tuesday, March 22, 2005 is World Water Day.

It marks the start of the Water for Life Decade, 2005--2015, a decade-long effort to reduce by 50% the proportion of persons without sustainable access to safe drinking water and basic sanitation.

See what the Center for Disease Control is doing. (new window)

Learn more from the World Health Organization. (new window)


3/21/05


We have updated the outdoor safety pages on our sister website:
DuluthStreams.org. (new window)

Learn what to do if you fall through the ice.
Learn how to escape from a rip current.
More tips and links...

 

 
6/21/04

Some new links from the latest MN Lakes Association e-newsletter:

Think Bottled Water Is Better Than Tap?
Bottled water has become big business, catering to people's concerns about tap water. Is bottled water really cleaner? The Minnesota Department of Health has a new fact sheet that discusses the relative safety of bottled versus tap water. Check it out here: www.health.state.mn.us/divs/eh/water/com/fs/bottledwater.html

The Hottest New Landscaping Trend---Rain Gardens
Rain gardens are the hottest new landscaping trend. These do-it-yourself flower patches in your yard can clean up gritty storm water and keep our streams much cleaner. Click here (http://clean-water.uwex.edu/pubs/raingarden/) to learn how to create your own rain garden using native wildflowers and grasses to create your own little storm water retention area in your yard. The article Gardens For a Rainy Day in the June DNR Volunteer Magazine also provides practical tips on planting a rain garden (http://www.dnr.state.mn.us/volunteer/mayjun04/raingardens.html)

4/30/04 View the Green Works video entitled "The Lake Access Project".
3/23/04

 dihydrogen monoxide!
Thanks to Water on the Web (WOW) National Advisory Team member Earl Byron in California for bringing the following to our attention:

Posted on Sun, Mar. 14, 2004 in the San Jose Mercury (California) News from the Associated Press.

SoCal city falls victim to Internet hoax, considers banning items made with water. This article went on to report that well meaning officials in the City of Aliso Viejo, California were considering banning foam cups after they learned that the chemical dihydrogen monoxide was used in their production. Although there may be other reasons to consider such a measure, and although the chemical is odorless and tasteless and can be deadly if accidentally inhaled, it is also essential to life on earth and the major reason for the current explorations of Mars. They should have been subscribing to the WOW Newsletter.


6/16/03 The Medicine Lake unit is up and running.
5/22/03 The Association of Medicine Lake Area Citizens (AMLAC) now has a website.
3/4/03 A mystery has been solved.
The mysterious hole in the ice that showed up this past winter in North Long Lake near Brainerd was formed by upwelling groundwater. Check out the "Lake Detective" for an explanation.
1/28/03 Curious about other Minnesota water bodies?
Check out the Duluth Streams web site. This project focuses on urban streams and stormwater issues in Duluth, MN. As in LakeAccess, Duluth Streams has a real-time data emphasis, with 3 stream monitoring stations deployed in three trout streams
.

1/23/03 Ground water suspected in 'black holes' on Long Lake, Forest Lake
Read about mysterious warm spots in Minnesota lakes in this January 22, 2003 article printed in the Minneapolis Star Tribune.


1/15/03 U.S. Appeals Court Upholds Runoff Rule
WASHINGTON, DC, January 15, 2003 (ENS) - Small cities, counties and developers must protect waterways from stormwater pollution, a federal appeals court ruled Tuesday. The court found that the U.S. Environmental Protection Agency's stormwater program is constitutional, rejecting claims that the agency exceeded its authority by requiring cities and developers to decontaminate stormwater before discharging it into rivers, lakes and coastal waters.

read the full article at the Environmental News Service

11/19/02

reprinted from Minnesota Lake Association's (MLA) October 24, 2002 monthly Lakes newsletter:

The Minnesota Phosphorus Lawn Fertilizer Law is outlined in a new fact sheet from the Minnesota Office of Environmental Assistance (OEA). Starting this year, it is required by Minnesota state law to clean up any fertilizer spread or spilled on paved surfaces. Starting in 2004, the laws requires the use of 0% phosphate lawn fertilizer in the seven county metro and 3 percent phosphate or less lawn fertilizer in Greater Minnesota (with exceptions for new lawns or when a soil test shows a need.)
View the fact sheet at http://www.moea.state.mn.us/campaign/download/phosphorus.pdf.
Quantities of the fact sheet are available at no cost from the Minnesota Office of Environmental Assistance;
call 800-877-6300 (Metro 651-215-0232), or e-mail clearinghouse@moea.state.mn.us

11/04/02 Both RUSS units are off their respective lakes.

 
10/16/02 Personal Watercraft Issues
Public debate over the use and abuse of Personal Watercraft ( PWC's, Jetskis, Seadoos, and others) is a passionately argued water resource issue among water recreationists -not only in the Upper Midwest, but throughout the world. The conflict has some similarities to the debate about the use and regulation of ATV's and snowmobiles in that it may be oversimplified as simply another case of environmentalists trying to lock up a natural resource from recreationists. Recently, the American Canoe Association (ACA) published Hostile Waters: The Impacts of personal watercraft use on waterway recreation [923 KB pdf file]. This study reported that although PWC's comprised less than 10 percent of all vessels, they were involved in 55 % of all collisions in U.S. waters. The conclusions were based on the last 5 years of available accident data (1996-2000) collected by the United States Coast Guard (USCG) and state boating agencies and their statistics were verified by the USCG. To provide a counterpoint perspective, we have listed relevant websites in our Boaters section of LakeAccess. We have also reproduced an apparent Personal Watercraft Industry Association (PWIA) eight page response to Hostile Waters in this same section.

http://www.acanet.org
9/13/02 A fun site to learn about water conservation.
US Water News featured website for the month of September is http://www.H2ouse.org . This website was developed cooperatively with the California Urban Water Conservation Council. It is a handy place for homeowners to find out about water efficient equipment and practices for the home. Water conservation not only saves water but conserves the energy used for pumping and treating it as drinking water and as wastewater both in your home and via public agencies. In rural situations, it saves you well and septic system costs. It can also be an important factor in reducing surface and groundwater water quality degradation.
9/9/02 This has been one of the top 10 wettest summers in the Twin Cities.
9/5/02 The Halsteds Bay unit is going to be off-line for the next couple of weeks for repairs.
6/24/02 Both the Medicine Lake and Halsteds Bay units are up and running!
6/11/02

It's time to start preparing to celebrate the 30th Anniversary of the enactment of the Clean Water Act on October 18, 2002.

Learn more about the Clean Water Act or register to participate in National Water Monitoring Day by visiting www.yearofcleanwater.org.

6/10/02

Need an expert to answer your question?

You can always ask one of us (but we're the first to admit we don't know everything) but there are lots of experts out there. Try the On-Line Experts site.


4/29/02

The Governor signed the phosphorous-free fertilizer bill last week.

(from the MINNESOTA LAKES ASSOCIATION LEGISLATIVE REPORT: 4/29/2002)
The new law restricts the use of lawn fertilizer containing phosphorus to zero (0) percent in the seven-county metropolitan area and three (3) percent throughout the rest of the state unless a soil test is done and proves that phosphorus is needed. A soil test, using a mail-in kit, would be good for three years. Golf courses would be exempt from the new law, as would new lawns.

Local units of government in the Greater Minnesota 80 counties could adopt a zero percent standard throughout their county, city, or township through an ordinance until January 2004, when the new law goes into effect. If they pass an ordinance more restrictive than three percent they would have to inform the State Department of Agriculture of their plans. Local outstate governments would also have until August 1, 2002 to pass ordinances that would restrict the sale of phosphorus lawn fertilizer, as well as, the use of the product.

Enforcement of the new law would be done locally. The new law also includes language on development of consumer education information atthe retail level. MLA will be involved in this process.

 

4/16/02

The ice is out!

The ice went out on Lake Independence yesterday, and it went out on Lake Minnetonka today (the average ice out date for Lake Minnetonka is 4/15).

 

4/3/02

The Lawn Fertilizer Phosphorus Bill Passed

Effective Jan. 1, 2004...

No greater than 3% P2O5 fertilizer within all areas in Minnesota, zero in the metro area.

 

3/28/02

Status of Lawn Fertilizer Phosphorus Bill in the House

It is anticipated that the Lawn Fertilizer Phosphorus Bill, SF 1555, will be voted on Tuesday, April 2nd, in the House. Rep. Leppik is introducing the bill. The MN Chamber of Commerce has come out against the bill, and the vote may
be tight.

It is anticipated that an amendment will be offered by Rep. Dorman to allow use of 3% P2O5 lawn fertilizer state-wide and preempt local ordinances that are more restrictive (e.g., 0% P2O5).

If the House version passes with the 3% P2O5 statewide amendment, then two possible outcomes are anticipated from conference committee (differences between House and Senate versions of a bill are ironed out in conference committee):

1. No compromise can be struck and the bill dies, or,

2. A compromise will be struck which removes the 3% P2O5 statewide
amendment.

Note the liberal use of the word "anticipated"! Nothing is for sure in the law making process.

 

3/8/02

Senate votes 65 - 1 on SF 1555, Lawn Fertilizer Phosphorus Bill

SF 1555, the Lawn Fertilizer Phosphorus Bill, passed the Senate 3-8-02 on a final vote of 65 - 1. The one opposition vote was Senator Mady Reiter, of Shoreview. The bill passed a "General Orders" vote on 8-7-02 by 55 - 3.

The bill was amended twice on the floor. One amendment allows local units of government to continue to regulate "raw" manure handling (i.e., not processed and bagged), something they need to do administer feedlot programs.

The other amendment allows enforcement of lawn fertilizer regulations to be carried out by either local units of government or the Minnesota Department of Agriculture.

HF 1524, the House version of the bill, is expected to be voted on yet this session, but it is not known when. There are slight differences between SF 1555 as passed and HF 1524 in its present form. These differences will need to be rectified on the House floor, or in Conference Committee if the two bills do not match in their final passage.

For information on HF 1524, or its author, Rep. Leppik, go to: http://www.house.leg.state.mn.us/

Both bills regulate the use of lawn fertilizers containing phosphorus in order to reduce phosphorus pollution of lakes and rivers.

Basic provisions of the bills are:
• Use only 0% P2O5 lawn fertilizer in the seven county metro area, unless the lawn is newly seeded or a soil test shows phosphorus need.

• Use no higher than 3% P2O5 lawn fertilizer outside of the seven county metro area, unless the lawn is newly seeded or a soil test shows phosphorus need.

• Local units of government outside of the seven county metro area can opt to change their 3% P2O5 restriction to a 0% P2O5 restriction.

• All fertilizer applied to impervious surfaces (driveways, sidewalks, streets), needs to be cleaned up.

 

2/27/02

Lawn Fertilizer Bill passes House Committee

HF 1524, the House bill regulating the use of phosphorus lawn fertilizer, passed the House Committee on Local Government and Metropolitan Affairs on 2/27/02.

The bill now goes for a vote on the House floor unless a chairperson of another House committee requests a hearing. That does not seem likely, but can happen.

Representative Leppik requested a "delete all" amendment to replace existing HF 1524 language with new language she presented. She also requested an additional amendment to the "delete all" language. Both amendments were approved.

The amended language to HF 1524 follows closely the language in SF 1555, Senator Higgins' bill that made it through Senate committees last week. BUT there are two main differences:

Preemption (authority the state can withhold from local government)
Senate bill (SF 1555) takes authority for regulating phosphorus lawn fertilizer USE away from local government, but allows local government to continue regulating the SALE of phosphorus lawn fertilizer.

House bill (HF 1524) takes authority for regulating BOTH phosphorus lawn fertilizer USE and SALE aw ay from local government, but allows local ordinances regulating phosphorus lawn fertilizer SALE pa ssed by August 1, 2002, to stay in effect.

Reporting back to legislature
House bill (HF 1555) requires the Commissioner of the Minnesota Department of Agriculture to report back to the legislature by 1/1/2007 (five years after the bill's enactment) as to the bill's effectiveness.

Senate bill (SF 1524) makes no such provision.


WHAT'S NEXT?
Both the House and Senate bills are heading for floor votes. They are very similar, but do differ. Either the differences will be patched up with floor amendments, or in conference committee if the House and Senate approve bills with different language. Both bills set January 1, 2004 as their effective date.

Go to http://www.senate.leg.state.mn.us/ for information on SF 1555, Senator Higgins, and the Senate schedule.

Go to http://www.house.leg.state.mn.us/ for information on HF 1524, Representative Leppik, and the House schedule.

 

2/25/02

SF 1555, Lawn Fertilizer Bill, clears Senate Ag Committee with amendments

The first engrossment of SF 1555, the bill that restricts use of phosphorus lawn fertilizer, passed the Senate Agriculture Committee on 2/22/02 with these amendments (paraphrased):

1. Clarification that, besides the special provisions made in this bill for phosphorus lawn fertilizers, local units of government cannot regulate agricultural fertilizers.

2. Only speciality fertilizer (bagged lawn and garden fertilizer) will be required to assure their reported nutrient content is within given minimum and maximum allowances. Bulk mixed agricultural fertilizers will be exempt from staying within maximum allowances since it is hard to mix with accuracy using large equipment.

3. Organic fertilizer will be held to the same phosphorus content standard as inorganic fertilizer. Previously, up to a 2% P2O5 organic fertilizer could be used in areas with a 0% P2O5 restriction.

4. All lawn fertilizer applied to impervious surfaces, whether it contains phosphorus or not, needs to be cleaned up. Previously this clean up provision was required of fertilizer containing phosp horus only.

The next stop for SF 1555 is the Senate floor for a vote. It could have gone to the Senate State and Local Government Committee, but Senator Vickerman, who chairs that committee and also sits on the Senate Ag Committee, allowed that step to be by-passed providing the bill's author, Senator Higgins, works out any outstanding concerns before the bill goes to the Senate floor for a vote.

Now the bill needs to be moved through the House side of the legislature.
Representative Leppik is sponsoring the bill as HF 1524, a bill from last session that will likely be modified to match the current Senate version.

First step for HF 1524 is the House Local Government Affairs Committee. If it passes that committee it likely will move the the House Agriculture Committee and maybe also the House Environment Committee.

For information on SF 1555 and Senator Higgins go to: http://www.senate.leg.state.mn.us/

For information on HF 1524 and Representative Leppik go to: http://www.house.leg.state.mn.us/

For information on House Committee scheudules, go to: http://www.house.leg.state.mn.us/hinfo/wsched .htm

 

2/20/02

Hearing Notice! regarding SF 1555, the Senate bill concerning regulation of phosphorus lawn fertilizer
Friday, February 22, 2002
Senate Agriculture, General Legislation & Veterans Affairs
Room 107 Capitol

9:00 AM
(get driving instructions at http://www.leg.state.mn.us/leg/capitol.htm)

Let the members of the Senate Agriculture Committee hear from you regarding the bill to allow local governments to pass more restrictive options than 3 percent phosphorus fertilizer limits

 

2/18/02

The next stop for SF 1555, the Senate bill concerning regulation of phosphorus lawn fertilizer, is the Senate Agriculture committee. It must pass through the committee by Friday, February 22 to "stay alive" in the session.


To find out more about the current status of the bill, visit the Environment and Natural Resources Committee home page and search for SF 1555 in the Bill Information search section.

 

2/14/02

At today's meeting of the Environment and Natural Resources Committee, Senator Higgins moved a "delete all amendment" on SF 1555, the Senate bill from last session concerning regulation of phosphorus lawn fertilizer. The committee supported the motion, and in so doing emptied the contents of the bill and replaced it with new language. Then new bill language passed committee with a strong majority.

The provisions of the new SF 1555 are summarized on the February 14 Watertalk Up-date.

 

2/4/02

A new section has been added describing the Lake Access II Lawn Fertilization Study. It includes the study design and recent results from the 2001 lawn runoff study, GIS maps, and current and historical data on Medicine Lake. It will also soon include stream data from Plymouth and Ridgedale Creeks including new stream data visualization tools.

2/1/02

The Citizen Action section has been expanded and now includes a Community Calendar

11/30/01

Both the Medicine Lake and Halsteds Bay units have been removed for the winter. Biweekly winter profiles will be taken as soon as the ice is safe.

 

11/14/01

The Senate Environmental Protection Subcommittee held a public hearing on the issue of restricting the sale and use of phosphorus in fertilizer used on turf at the State Capital. The speakers included city officials, park managers, turf industry representatives, private citizens, University of Minnesota faculty, and state agency personnel. The mayor of Shorewood, Woody Love, started the hearing by voicing a few main points that were subsequently repeated by the majority of other meeting speakers. He emphasized that the proposed legislation would be; relevant as approximately 80% of the lawns in the Twin Cities metro do not require additional phosphorus inputs by lawn fertilizer, a "restriction" on the use not a ban, and only one part of the overall plan to reduce phosphorus inputs to waterways. The turf industry representatives did not support the legislation as they claim that phosphorus-free fertilizer may actually be bad for the environment.

10/17/01 The Senate Environmental Protection Subcommittee will hold a public hearing on the issue of restricting the sale and use of phosphorus in fertilizer used on turf on Wednesday, November 14 in Room 15 of the State Capitol at 1 PM. Please join us if you are interested in the subject. Please contact Julie Rusk in my office if you would like to testify. 651-296-9246 or email: julie.rusk@senate.leg.state.mn.us. The city of Minneapolis recently passed an ordinance restricting the sale and use of phosphorus. St. Paul is also considering such an action.
10/3/01
City of Minneapolis bans use of most phosphorus-containing lawn fertilizers

Read Duluth News-Tribune article

8/3/01 The Halsteds Bay and Medicine Lake RUSS units are both up and running.
7/25/01 The Medicine Lake unit is up and running. Halsteds Bay should be on-line by the end of this week.
6/25/01

Five more metro area lakes found to have Eurasian watermilfoil !
MN DNR press release 6/19/01
For more information, contact Chip Welling, DNR Ecological Services, (651) 297-8021.

Despite a cool, wet spring, the total number of Minnesota water bodies infested with Eurasian watermilfoil grew by five in the first months of this year's open water season. This brings the total number of Minnesota lakes, wetlands and rivers known to be infested with this harmful exotic plant to 126.

New and widespread infestations were found in Parley, Wasserman and Eagle lakes in Carver County, and Sunset Lake in Washington County. The presence of widespread milfoil indicates that the plant became established in these lakes some number of years before it was discovered, according to the Department of Natural Resources (DNR) officials. A small infestation was found in Galpin Lake in Hennepin County.

"While it's disheartening each time new infestations of milfoil are reported, we believe that Minnesota has slowed the spread of this exotic," said Chip Welling, DNR Eurasian watermilfoil coordinator. According to Welling, the rate of spread is low due to the high level of awareness among boaters about the need to always remove all aquatic plants from their boats, motors and trailers before leaving accesses.

The high level of awareness is attributed to efforts by watercraft inspectors, local lakeshore associations, and others to inform users of Minnesota lakes and rivers about what they can do to prevent the spread of milfoil and other aquatic exotic species.

Though 119 Minnesota lakes now have milfoil, this represents only 1 percent of all the lakes in the state. "Users of Minnesota's lakes and rivers need to continue to work to prevent the spread of milfoil to the 99 percent of our lakes that do not have the exotic," said Welling.

6/20/01 Public Involvement in EPA Decisions - A National Dialogue via the Internet ===========================================================
Convened by the U.S. Environmental Protection Agency Hosted by Information Renaissance http://www.network-democracy.org/epa-pip
July 10 - July 20, 2001 You are invited to participate in an online public discussion with EPA and panels of experts on improving public involvement in EPA decision-making. Please join a broad cross-section of individuals who will share their thoughts and ideas on this important topic with each other and with the Agency.
Over the course of 10 days (including a Saturday), the participants will discuss specific topics drawn from EPA's newly drafted Public Involvement Policy. EPA is now seeking your thoughts and ideas on how it should implement this policy. Because this will be a web-based discussion, you can select the topics that interest you and participate at your convenience.
A revolving panel of experts will discuss the main aspects of the draft Public Involvement Policy with each other and with approximately 500 participants. Among the topics that we will discuss >are the following: 1) Identifying and involving the public, including those hardest to reach; 2) Providing information to the public; 3) Creating effective public involvement opportunities during rulemaking and permitting; and 4) Encouraging collaborative processes.
The Dialogue is an excellent opportunity for citizens, representatives of industry, environmental groups, small businesses, states, local governments, tribes, and other groups to learn more about the draft Policy and to share their thoughts and concerns with EPA. To learn more about the Dialogue and to register to participate visit the Dialogue Web site at: http://www.network-democracy.org/epa-pip For more information: Send e-mail to Patricia Bonner at U.S. EPA: bonner.patricia@epa.gov. or Information Renaissance: epa@network-democracy.org or call 888.638.5323.
5/25/01 The Medicine Lake unit has been deployed but we are having some technical difficulties.
5/18/01 Great North American Secchi Dip-In 2001
Programs and Volunteers Needed!
Contribute to a Snapshot of North American Water Quality
June 30 - July 15, 2001

To participate, enroll your program at their Website
(http://dipin.kent.edu). All volunteers in your program will receive a
summary of the Dip-In 2000, whether or not they participated in the 2000
event.

3/30/01 Ice-Out Watch : The Minnesota Climatology Working Group has a web page showing ice-out dates for a number of Minnesota lakes including Minnetonka.
2/8/01

Does growing development near Twin Cities lakes threaten the region's excellent fishing? Find out by going to the MN DNR website to an article called "The road to poor fishing".

Check out the latest Lake Water Quality Index Map for Minnesota (smaller version) The map shows the trophic state index (TSI) and secchi depth for lakes across the state. You can find your lake by going to the LakeBrowser.

1/03/2001 Download the EPA EMPACT Technology Transfer Manual
You'll need Adobe Acrobat and some time, it takes a bit to download.
11/10/00 Lake Access and Water-on-the-Web have won the 2000 Technical Excellence Award for public education and research, from the North American Lake Management Society, in recognition of extending effective and creative education in lake restoration, protection, and management. Rich Axler and Chris Owen were in Miami to receive the award
11/10/2000

The Russ units have been removed from the lakes and we're waiting for ice-on.

 

10/20/2000 News Flash.....James Johnson of Hennepin Parks comes face to face with furry RUSS saboteur.
Today as James searched for a reason why the Halsteds RUSS unit stopped working he noticed chew marks along the profiler cable. As he looked into the middle of the RUSS buoys he came face to face with the culprit. A muskrat has made the unit his home and seems to like chewing on cables. More to come.....
10/2/2000

Lake Access attends EPA Environmental Monitoring Conference Boston, MA

(Click the Cod to see Lake Access in action)

9/29/2000 The Lake Independence RUSS (our oldest unit) is in the shop for repairs. We'll let you know when it gets back on-line.
8/24/2000 The West Upper unit needs a chance to get back to full battery power so we will cut back on the number of profiles from four to two per day at least for a few days.
7/18/2000 Lake Access staff conducted a survey of west metro landowners last fall. Please check out the results.


6/23/2000

 


 

Lake Access attends the Carp Festival!

Lake Access and RUSS were featured at the Mississippi River Carp Festival held on Saturday, June 17th. Kids and adults played with a model RUSS unit and talked with Lake Access staff members. The Lake Access refrigerator magnets were a big hit, contact us if you'd like one!


Click here to decide who's the carp and who's the crab (crayfish really)
6/15/2000 Lake Access Website is undergoing a major renovation and is changing daily. Be sure to check often for new features.
3/22 - 3/23/2000 RUSS units deployed on to Lakes Minnetonka and Independence for the 2000 open water season.
3/18/2000 Ice-off Minnetonka. This is the second earliest ice-off in 123 years! The earliest ice-out was March 11, 1878. Independence ice was gone 3/11/00.

What can turbidity tell you?

Look how clear the water is under the ice by running either the color mapper or examining the colorized DxT plotter from the Data Visualization Toolkit. The turbidity is extremely low and then gradually increases after ice-out. We think that the discrete blobs of turbidity (spikes in the Profile Plotter plots and green smudges in the Color Mapper and DxT plots) may be due to resuspended sediment induced by wind mixing of nearshore and perhaps bottom sediments before the lake stratifies. Later on in the spring and summer, algal growth provides a more important contribution to turbidity.

Thunderstorm Watch !

Storm Tracker
Color Mapper

Our RUSS data set and Hennepin Park's water chemistry data from last summer showed that sudden mixing events at Halsteds Bay could have dramatic effects on water quality. Severe thunderstorms with high winds and tornado warnings ripped through the Twin Cities area in August and September 1999, leading to sudden mixing and re-aeration events at the Halsteds Bay RUSS site in Lake Minnetonka. The event ultimately had profound water quality consequences by disrupting stable thermal stratification and introducing high nutrient/low oxygen bottom water into the upper sunlit layer of the bay resulting in an obnoxious algae bloom some days later. This, in turn, led to further changes in the depth and time patterns of dissolved oxygen, pH and turbidity. The nearby West Upper Lake water column responded very differently to the wind event and produced much smaller, if any, serious water quality effects.

In fact, there are economically important land and lake management implications that derive from these data in terms of how to most efficiently restore the degraded water quality in Halsteds Bay. Restorative management decisions involving millions of dollars of tax monies are currently being discussed for Halsteds Bay. Such storm-related events were suspected, but prior to our RUSS data, were not documented due to their transient nature and the danger of manual sampling during severe weather. In fact, several of these events were observed in August 1999 (see figures below).

In each case, temperature profiles didn't tell us the state of mixing of the bay since variations from surface to bottom were only about 1oC. However, dissolved oxygen (and to a lesser extent pH and EC25) clearly indicated that the lower half (~5 m) of the water column dramatically changed from extreme anoxia to >75% saturation and then back again to anoxia over intervals of ~ 24 hours in mid and late August/early September. During the initial mixing, the influx of anoxic water to the "epilimnion" actually decreased the level of DO to ~5 mg/L, which could potentially impact fish communities. In addition, water samples collected on August 25, about 10 days after the first mixing event, showed that about 3200 kg (over 7000 lbs of P) was suddenly injected into the upper sunlit euphotic zone. This represented an areal phosphorus load of about 3x the annual load estimated to enter Halsteds Bay from Six Mile Creek, its major tributary. The sudden input of P appears to have then caused an increase in algal growth, seen as a chlorophyll increase over the same manual monitoring interval (Barten and Vlach 1999, L. Minnetonka Annual Monitoring Report). Recall that 7000 lbs of P can potentially lead to over 3,500,000 lbs of algae !

These new data, that would likely not have been acquired without remote sensing, suggest that water quality in nutrient enriched lakes of intermediate depth (perhaps 5-10 meters) may often be controlled by weather events. The data also indicate that watershed BMPs, alone, may not be successful in improving the water quality of these bays without concurrently reducing internal P-loading. Of course this does not diminish the importance of preventing increases in external P-loading from old and new developments over the long-term. However, it does offer important insights into the cost-effective management of water quality for 6 bays on the west and north end of the lake that have shown significant downward trends in water quality over the past 5 years.

Color maps of mid-late summer depth profiles of temperature and dissolved oxygen for Halsteds Bay and West Upper Lake regions of Lake Minnetonka.
The temperature ranges from warm (red) to cold (blue) and dissolved oxygen ranges from high (green) to low (brown) to anoxia (black).
 
 

 

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