Water Quality Initiatives

Our cherished Walnut Lake, consisting of 236 acres with a depth of over 100 feet, is in trouble.  As most of you know, the water quality of our lake has been deteriorating over the past few decades resulting in annual beach closings, the loss of several fish species (trout and walleye), an abundance of invasive weed growth, and several other unpleasant issues.  There have never been any significant remediation nor mitigation efforts enacted to combat this downward spiral.  This letter is intended to provide you with a brief update on the work being done to understand, monitor, manage and hopefully, reverse the ongoing and worsening water quality issues afflicting our lake. 

WHO IS WORKING ON THIS ISSUE AND WHAT ARE THEY DOING?

‘Lake Shore Residents of Walnut Lake’ is an incorporated committee of concerned lakefront residents who began volunteering time and effort in 2019 to gain a deep understanding of the factors that are contributing to the declining water quality in our lake.  This process began with the commissioning of a comprehensive ecological study performed by Dr. David j. Jude, Ph.D (of Freshwater Physicians, INC.).  This study was based on physical, chemical, and biological measurements and observations, including sampling of inlets/outlets, shallow water, deep water, sediments, and animal/plant life provided our baseline understanding of the issues facing the lake.  We followed this up by working with West Bloomfield township environmental leadership (environmental manager John Roda) as well as the Oakland County drain commission, to map and identify every known drain that sends water into the lake.  We then sampled, and sent for testing, water from each drain intake site that we could access, to further home in on sources and types of contamination.  Next, we met with community/association leadership from Pine Lake and Sylvan-Otter Lake to learn how our neighboring lake communities manage water quality issues, gather information on various remediation techniques, and understand both cost/benefit and best practices of these various methods they have employed.  Finally, we met two separate companies with a proven track record that provide water quality management for several nearby lakes (including Pine and Sylvan-Otter). The meetings required touring and GPS mapping our lake to identify areas where non-native nuisance vegetation is thriving (essentially the entire perimeter of the lake).  We also toured some of the nearby lakes where these firms have been conducting remediation efforts to see firsthand the results of the work they’ve performed in nearby lakes.  Both companies have provided comprehensive quotes for several treatment options based on the identified issues.  We are now working to present all this information to our community associations so that we can work collaboratively throughout the Walnut Lake Watershed community on the next steps.  At this time we are comfortable recommending Savin Lake Services to lead our treatment and remediation efforts. Additionally, we have developed a website (www.WalnutLakeMI.com) that will provide everyone in our community with a single point of access to all information related to the environmental management of Walnut Lake. 

WHAT IS THE CAUSE OF THE DECLINING WATER QUALITY IN WALNUT LAKE?

Based on the findings of the comprehensive ecological study as well as the recent testing performed on the lake, the principal cause of long term, measurable (and observable) water quality deterioration is due to an excess amount of phosphorus in the lake water.  This excessive nutrient enrichment leads to invasive aquatic species taking over the lake.  A cascade of events in turn causes lower oxygen levels in the lake by blocking off the sun to the desirable plants that produce oxygen.  For simplicity’s sake, the higher the level of oxygen, the healthier the lake.  Our phosphorus levels as measured by Dr Jude, are high.  While phosphorus is a natural and essential nutrient for plant and animal growth in the lake and is not directly toxic, an excess amount of phosphorus promotes the unwanted growth of invasive Eurasian Milfoil and algae.  The algae itself can be toxic, and if ingested can be harmful to people and potentially fatal for pets.  Further, as the algae dies, it is broken down by bacteria and the subsequent decay process consumes oxygen from the lake.  This, in turn, creates ‘dead zones’ or areas of low oxygen where fish can’t survive.  This has been one of the reasons for the continued loss of native fish species in the lake which have fallen from north of 30 species several decades ago, to fewer than 10 today.

Several other tangible and unpleasant effects of the excess phosphorus are already becoming noticeable throughout regions of the lake.  One such impact is the propagation of tall weed beds (the weed beds make areas of the lake unswimmable and are often hazardous to outboard boat motors).  Another is the slick/slimy plant blooms which are spreading on the lake floor, and which can make walking around in the lake mucky and generally unpleasant.  

WHERE IS THE EXCESS PHOSPHORUS IN THE LAKE COMING FROM?

The phosphorous is largely introduced from 2 major sources. One is internal loading from the lake itself and is produced by the sediment at the bottom of the lake. The more sediment, the more phosphorus. Two, external sources such as water running unimpeded by natural vegetation into the lake from source drains, car washing in driveways, and lawns and leaves around the lake amongst others. There is evidence of contamination from fertilizer runoff from lakefront homes that don’t follow Township Ordinances, and from subdivisions lawns that ultimately drain into the lake. These areas can be quite a distance from the lake, as the watershed that drains into the lake is approximately four square miles in size.

HOW DO WE COMPARE TO OTHER LAKES IN THE REGION?

Our closest comparable lakes in the area are Pine Lake and Sylvan, Otter lake which have also observed a similar decline in water quality in recent years. However, their residents have both been undertaken remedial action for at least 5 years.  Like Walnut Lake, Pine Lake and Sylvan Otter lakes are wholly private lakes comprised of homeowners and lakefront beach associations who also identified excess phosphorus levels as the primary contributor to the overall and noticeable decline in health of their lakes. Each of those communities subsequently undertook multiple avenues to address their problems. These included water treatment for phosphorus, weed treatments, and education of their members about the causes of the problems.  We have been informed that they were able to reduce the measurable phosphorus in their lake with 24D and Biowash, (amongst other methods).  In addition to this measurable impact, they have also communicated that their residents have observed noticeably clearer water throughout the shoreline of the lake, along with significantly less weed and algae growth throughout the lake.  Given that Pine Lake is a similarly situated, but larger lake, we find their results to be very encouraging in terms of our ability to make meaningful improvements to water quality in Walnut Lake.

WHAT ARE THE REMEDIATION AND MANAGEMENT OPTONS? (ordered by cost and benefit)

1) Mitigate incoming sources of excess phosphorus into the lake

Self-mitigation is the least expensive but, is difficult to accomplish and almost impossible to enforce.  We will be working on ways to inform our community of the risks to the lake from riparian abuses as well as working with the cities of West Bloomfield and Bloomfield township on potential strategies to limit, mitigate or otherwise discourage such abuses.  

2) Water Foul Population Management

Reducing the population of Geese (and Ducks) that live on the lake is something that has been undertaken in the past, with generally positive results.  There continues to be a significant, though much smaller, population of waterfowl species on the lake and continued reduction of this population is strongly encouraged.  The primary concern with the birds is the volume of toxic droppings that end up in the lake and contribute to dangerous parasite growth in the water.

3) Biochemical water treatment

This will entail engaging companies that specialize in lake water quality management to introduce phosphorus limiting elements to the lake. They accomplish remediation via the introduction of EPA and DNR approved herbicides which selectively target invasive species, while leaving native plants intact. Based on our research, this is the most common and cost effective strategy pursued by similarly affected parties attempting to manage excess phosphorus levels in their lakes. 

4) Hypolimnetic aeration

This would involve mechanically aerating oxygen depleted ‘dead zones’ in the lake.  This option will likely be prohibitively expensive due to the depth of these oxygen depleted ‘dead zones’.

5) Dredging

Dredging is the option of last resort should all else fail and the lake deteriorate into a swamp-like condition with out of control weed growth and dangerous levels of algae proliferation.  This is by far the costliest option (in the millions of dollars) given the depth and size of the lake, but it can return the lake to water quality conditions of a century ago.

WHAT WILL REMEDIATION COST AND HOW WILL IT BE FUNDED?

Unfortunately, remediation and water quality management are not a one-time expenses, but rather an ongoing annual maintenance commitment.   On a positive note, as remediation efforts take hold, and water quality improves, annual maintenance costs should correspondingly decline.  While we are still waiting for proposals from the two companies we have been in contact with, we are currently estimating initial remediation costs of $50K - $75K per year with the expectation that long term water quality maintenance costs will average closer to $20K-$40K per year.  We are proposing that funding will be raised thru the community associations in a similar manner to fundraising for the annual 4th of July Fireworks display.   It will be our recommendation that there will be tiered donation requests with lakefront homeowners being asked to carry the brunt of these costs.

WHAT ARE THE RISKS OF INACTION?

Left unchecked, the best-case scenario is that the water quality in our beloved lake we will continue the downward spiral of lake eutrophication, wherein the unbridled influx of nutrients will result in the continued growth of invasive plant species, a growth of the oxygen depleted ’dead zones’, further loss of additional fish species, and a general decline in the ability to enjoy all the benefits of our beloved Walnut Lake.  In a worse scenario, all the above factors occur to a greater degree, in a shorter time frame, and affect not just the quality of the water, but also the value of all our properties.  A ‘Dead Lake’ is not in anyone’s best interest! Ultimately, the cost and effort required to address these issues will only increase.  The time to act is now.