1. Introduction

The lakes within the Jefferson German Chain (JGC), West Jefferson, Middle Jefferson, East Jefferson, Swede’s Bay and German Lakes, do not meet State standards for due to excess nutrients and the presence of seasonal nuisance algae blooms. The Upper Canon Lakes Excess Nutrient Total Maximum Daily Load (TMDL) was published in 2014. The results of this study show the load reductions needed to meet state water quality standards. This report updates the information collected since the TMDL was developed, establishes goals, and provides recommendations for future projects and programs implementation. The purpose of the Jefferson German Chain Lake Management Plan (LMP) is to determine the appropriate course of action to improve the water quality of these lakes.

2. Background

A. Watershed Landuse

Watershed land cover plays a crucial role in the water quality of lakes. The watershed is the area of land that drains into a particular lake, river, or other water body. The types of land cover within a watershed, such as forests, urban areas, agricultural fields, and wetlands, greatly influence the quality of water that flows into the lake, see Section 3.A for more information.

The composition of land cover within a lake's watershed directly affects the quality of water entering the lake. Today, the percent developed in each of the JGC lakes subwatersheds ranges from 7% to 23% and the agricultural use ranges from 26% to 63%, Figure 1. Since 2013 there has been very little increase in development and some decrease in cultivated crops, Table 1. Many of the areas categorized in the 2013 land use report as Pasture/Hay are now classified as Grassland/Shrub. The natural areas of Forest, Wetland, and Grassland/Shrub have increased since 2013.

The largest two subwatersheds are the German and Swede’s Bay watersheds which both have a large portion of their land use categorized as cultivation. Agricultural production in the watershed is primarily corn and soybean fields interspersed with pasture and some small wetlands and wooded areas. Soil conservation and nutrient management programs are effective at mitigating phosphorus loading. Options for these programs are expanded on in Section 6. Development within the watershed includes single-family residential areas, including parcels along the perimeter of the lake. The mowed lawns and roadways runoff associated with these developed areas may contribute to nutrient loading to the lakes. Open water accounts for approximately 21% of the watershed area and wetland areas account for an additional 6% of the area. About 8% of the watershed is forested/wooded. The land cover within the watershed was used to develop a pollutant load model which is described in further detail in Section 5.

Table 1: Land Use Classification by Lake Subwatershed.

Land Use Classification	Lake Name	Percent of Land Area (2013)	Percent of Land Area (2023)	Change
Cultivated	West Jefferson	40	26	-36%
	Middle Jefferson	61	63	4%
	Swede’s Bay	47	53	14%
	East Jefferson	21	28	31%
	German Lake	41	37	-10%
Developed	West Jefferson	25	23	-9%
	Middle Jefferson	15	14	-9%
	Swede’s Bay	7	4	-37%
	East Jefferson	15	18	21%
	German Lake	9	7	-21%
Pasture/Hay	West Jefferson	21	32	50%
	Middle Jefferson	13	11	-18%
	Swede’s Bay	27	23	-17%
	East Jefferson	41	23	-43%
	German Lake	41	27	-34%
Forest	West Jefferson	5	9	83%
	Middle Jefferson	6	8	26%
	Swede’s Bay	10	10	1%
	East Jefferson	12	14	20%
	German Lake	13	12	-10%
Wetland	West Jefferson	7	9	31%
	Middle Jefferson	3	3	3%
	Swede’s Bay	5	8	68%
	East Jefferson	9	16	74%
	German Lake	7	14	98%
Grassland/Shrub	West Jefferson	2	2	-22%
	Middle Jefferson	1	2	89%
	Swede’s Bay	3	1	-63%
	East Jefferson	2	1	-55%
	German Lake	4	4	-6%

3. State of the Lakes

A. Nutrient Cycling in Lakes

External Load

An external load is a nutrient load originating from outside of the lake which is then delivered to the lake. External loads can come from point and non-point sources. Point sources have a discrete point of discharge to the lake. Common point sources to lakes include stormwater pipes, municipal and industrial wastewater discharge, and Confined Animal feeding operations (CAFOs). Point source discharges are regulated through NPDES. Non-point sources are not from discrete sources. The most common non-point sources to lakes are watershed loads. Watershed loads are dependent on land cover. The types of land cover within a watershed, such as forests, urban areas, agricultural fields, and wetlands, greatly influence the quality of water that flows into the lake. Watershed land cover plays the following roles in determining water quality in downstream resources:

Runoff and Erosion: Different land covers affect how rainfall and runoff move across the landscape. Forests and wetlands tend to slow down and absorb water, reducing the amount of runoff and erosion. On the other hand, urban areas and agricultural fields can increase runoff and erosion due to impervious surfaces and soil disturbance.
Sedimentation: Land cover influences the amount of sediment (soil particles) that washes into the lake. Excessive sedimentation can cloud the water, disrupt light penetration, and harm aquatic plants and animals.
Nutrient Loading: Agricultural areas can contribute to nutrient pollution through the runoff of fertilizers and manure. Urban areas can also introduce pollutants like nitrogen and phosphorus through stormwater runoff. These nutrients can cause excessive algae growth (eutrophication), leading to oxygen depletion in the water and negative impacts on aquatic ecosystems.
Pollutant Transport: Urban areas often produce various pollutants that can be transported into the lake through runoff. These pollutants might include chemicals, heavy metals, and toxins, which can harm aquatic life and human health
Buffering and Filtering: Natural land covers like forests and wetlands can function as buffers and filters. They can trap and absorb pollutants, nutrients, and sediment before they reach the lake, helping to improve water quality.
Temperature Regulation: Vegetated areas provide shade, which can help regulate water temperature in the lake. Excessive warming due to lack of vegetation can stress aquatic organisms and disrupt the lake's ecological balance.
Biodiversity and Habitat: Natural land cover types support diverse ecosystems, which in turn contribute to water quality. Diverse plant and animal communities can help maintain a balanced ecosystem that can better manage environmental changes and stressors.
Resilience to Climate Change: Certain land covers, such as wetlands and riparian zones (areas along water bodies), can provide resilience against the impacts of climate change, such as flooding and drought. They can store water, reduce flood risks, and recharge groundwater.

Internal Loading

Internal load is a phosphorus load which originates within the lake itself. There are several types of internal load sources including vegetation senescence, bioturbation, and legacy nutrients in the sediments. Sediment driven internal load requires specific conditions to manifest. Phosphorus release from lake sediments is influenced by various conditions. Due to past land uses, phosphorus laden sediment has accumulated within the lake and continues to be available for plant and algae growth. The following are key factors that can contribute to phosphorus release:

Anoxic Conditions: Phosphorus release is commonly observed in sediments that lack oxygen (anoxic conditions). When oxygen is depleted, certain microorganisms in the sediments start conducting anaerobic processes that release phosphorus. Under anoxic conditions, phosphorus bound to iron and manganese oxides is released and becomes available in the water column. Anoxic conditions result through two primary mechanisms:

1. Thermal Stratification: Lakes often undergo a process called thermal stratification, where the water column separates into distinct layers based on temperature. During the warmer months, the upper layer (epilimnion) receives sunlight and becomes heated, while the lower layer (hypolimnion) remains cooler. This temperature difference prevents mixing between the layers, limiting oxygen transfer to the hypolimnion and promoting anoxia.

2. Nutrient Enrichment: Excessive nutrient inputs, particularly nitrogen and phosphorus from human activities such as agriculture or wastewater discharge, can cause excessive algal growth in lakes. This leads to the development of algal blooms. When these algae die and sink to the bottom, their decomposition consumes oxygen, depleting it in the bottom waters and creating anoxic conditions.

Sediment Disturbance: Human activities and natural processes can disturb lake sediments which can lead to phosphorus release. When sediments are resuspended, phosphorus that was previously bound to particles becomes available in the water column. In shallow areas of the lake, wind and wave action can disturb the bottom sediments.

Redox Potential: The redox potential, which indicates the oxidation-reduction conditions, affects phosphorus release. High redox potential (more oxidizing conditions) tends to keep phosphorus bound to sediments, while low redox potential (more reducing conditions) favors phosphorus release.

pH and Alkalinity: The pH and alkalinity of the lake water also influence phosphorus release. Lower pH and alkalinity can increase the solubility of phosphorus, leading to its release from sediments.

The potential internal loading rate in JGC lakes has yet to be quantified. In BATHTUB model, Section 5, internal load is estimated as the residual load that is not accounted for by the external load. Internal loading can be quantified by measuring sediment phosphorus release rate and the anoxic conditions measured in the lake. The sediment phosphorus release rate is measured in a laboratory by incubating intact sediment cores collected from the lake under oxic and anoxic conditions. Additionally, sediment phosphorus content should be quantified to inform the required sediment inactivation management plans. A feasibility study is outlined in Section 6.A which will inform the internal load control plan.

Curly Leaf Pond Weed Senescence: Curly Leaf Pondweed (CLP) contributes to internal loading in two ways to internal loading. 1) Actual senescence of aquatic plant material and 2)BOD resulting in night-time dissolved oxygen concentrations that approach anoxic conditions in the absence of photosynthesis. CLP senescence occurs in mid-summer which can lead to increases in TP into the water column.

B. Phytoplankton & Algae

Phytoplankton are microscopic, free-floating plants that play a critical role in the ecological health of lakes. It is important to note that the terms "phytoplankton" and "algae" are often used interchangeably, but there is a distinction between the two. While all phytoplankton are algae, not all algae are phytoplankton. Algae can refer to any type of aquatic, photosynthetic organism, including those that are attached to surfaces or are large enough to be visible to the naked eye. Phytoplankton specifically refers to those algae that are small enough to float freely in the water column.

Some of the key characteristics and roles of phytoplankton in lakes include:

· Primary production: Phytoplankton are the primary producers in lake ecosystems, converting energy from the sun into organic matter through photosynthesis.

· Nutrient cycling: Phytoplankton help regulate nutrient cycles in lakes by taking up and storing nutrients like nitrogen and phosphorus, which can help prevent excessive algal growth and improve water quality.

· Food source: Phytoplankton serve as a primary food source for many zooplankton and other aquatic organisms, which in turn provide food for fish and other larger predators.

Algae are a diverse group of aquatic organisms found in lakes, ranging from single-celled organisms to larger, multicellular forms. They are important in aquatic food webs and can also impact water quality and human health. Three main groups of algae are commonly found: green algae, blue-green algae, and diatoms. These groups can be distinguished by their growth form and pigmentation.

C. regulatory Setting

The Clean Water Act (CWA) is a federal law enacted in 1972 to regulate and improve the quality of the nation's waters, including lakes, rivers, streams, and wetlands. The CWA establishes a framework for setting water quality standards and implementing measures to achieve and maintain those standards. The CWA requires states to assess and identify impaired waters, i.e., those that fail to meet their designated uses, such as swimming, fishing, and maintaining a healthy aquatic ecosystem. States must then strive to restore impaired waters by developing a Total Maximum Daily Load (TMDL) which is a calculation of the maximum amount of a pollutant a water body can receive while still meeting water quality standards.

Minnesota’s impaired waters program is managed by the Minnesota Pollution Control Agency (MPCA) in collaboration with other state agencies, tribes, local governments, and citizens. Its main goal is to assess, monitor, and restore waters that do not meet water quality standards due to pollution or other factors. The MPCA compiles a list of impaired waters, known as the "Impaired Waters List," which is submitted to the U.S. Environmental Protection Agency (EPA) for approval.

The Jefferson German Chain lakes were placed on the impaired waters list for nutrients in 2008 at which time it was determined to be impaired for excess nutrients. The most recent assessment of the lakes, completed in 2022-2025, showed continued impairment. Minnesota's Water Quality Standards provide qualitative and quantitative goals for waters that are protective of Fishable, Swimmable conditions [Water Quality Standards and Classifications]. The applicable water quality standards are outlined below, Table 2.

Table 2: Water Quality Standards

Lake	Lake Type	TP Standard (ug/L)	Chl-a (ug/L)	Secchi (m)
West Jefferson	Deep	40	14	1.4
Middle Jefferson	Shallow	60	20	1
East Jefferson	Deep	40	14	1.4
Swede's Bay	Shallow	60	20	1
German Lake	Deep	40	14	1.4

D. Lake Monitoring

Lakes have been monitored at different frequencies over the years. Table 3 summarizes the data that has been collected to date for total phosphorus (TP). Figure 3 is a visual representation of all of the TP concentrations observed within the lake systems. Figure 4-Figure 8 show the time series of annual average for each eutrophication parameter. The phosphorus levels within Swede’s Bay are higher compared to the other lakes in the chain. German Lake has the lowest levels of phosphorus in the chain. However, all lakes are exceeding the standards, as seen in Table 3.

Table 3: Total Phosphorus Data Summary.

Lake Segment	2015 to 2025 Average Observed TP (ug/L)	Lake Type	TP Standard (ug/L)	Years with Observations between 2015 and 2025
West Jefferson	97	Deep	40	2022
Middle Jefferson	88	Shallow	60	2022, 2025
East Jefferson	83	Deep	40	2022, 2024, 2025
Swede's Bay	304	Shallow	60	-
German Lake	75	Deep	40	2022, 2024, 2025

West Jefferson

West Jefferson has total phosphorus concentrations that peak on average in July some years there is a peaks in May which may be due to large spring storm events washing phosphorus into the lake. The water quality parameters, though collected infrequently, are fairly consistent throughout the decades and are above the standards.

Figure 4:West Jefferson Lake Water Quality Time Series

Middle Jefferson

Middle Jefferson generally peaks in total phosphorus in July but can peak throughout the growing season as well. Middle Jefferson shows a steady improvement in Secchi depth starting in the early 00s and are below the TP and Secchi standard in the most recent sample.

Figure 5: Middle Jefferson Lake Water Quality Time Series

East Jefferson

East Jefferson shows a peak in total phosphorus concentrations in August. The Secchi depth results are oscillating around the standard. TP and chlorophyll-a are consistently above the standard.

Figure 6: East Jefferson Lake Water Quality Time Series

Swede’s Bay

Swede’s Bay has concentrations peaking in July and September. The September peak may be a result of late season phosphorus being released from curly leaf pondweed that has died off. This lake has the highest total phosphorus values in the chain and is likely acting as a treatment system before water is discharged down the chain of lakes.

Figure 7: Swede’s Bay Water Quality Time Series

German

German Lake Secchi depth is often meeting the standard. However, historically chlorophyll-a concentrations are high. Total phosphorus concentrations peak on average in July. The TP concentrations are consistent with previous years.

Figure 8: German Lake Water Quality Time Series

E. Tributary Monitoring

In 2008 and 2009 all 4 tributaries and the one outlet of the Jefferson German chain of lakes were monitored during the growing season. The results, seen in Table 3 and Figure 9 show phosphorus concentrations well above the Class 2B stream standard of 100ug/L. The inlet flowing into Middle Jefferson from the north shows consistently very high Total Phosphorus concentrations over all the years it was monitored. The land use is primarily agriculture which accounts for high phosphorus load, but it should be further investigated what is causing the exceptionally high TP concentrations at S005-439.

Table 4: Total Phosphorus Sampling Statistics for each stream sample point

Location	Total Phosphorus (ug/L)				Years Sampled	Count
Location	Min	Max	Average	Standard	Years Sampled	Count
North Inlet to Middle German (S005-439)	265	3,440	1,183	100	2002-2003, 2008-2009	63
Southwest Inlet to Swede's Bay (S004-155)	52	1,110	226	100	2002, 2008-2009	46
Southeast Inlet to Swede's Bay (S005-436)	51	950	252	100	2002, 2008-2009	44
South Inlet to German (S004-154)	52	886	262	100	2002, 2008-2009	37
Outlet from German (S005-440)	11	132	45	100	2008-2009	42

F. Aquatic Macrophytes

Aquatic macrophytes, or underwater plants, play an important role in the ecological health of lakes. Some of the key ecological benefits provided by these plants include:

· Oxygen production: Aquatic macrophytes produce oxygen through photosynthesis, which helps maintain healthy oxygen levels in the water and supports aquatic life.

· Habitat creation: These plants provide important habitat and cover for fish, invertebrates, and other aquatic organisms, which can improve overall biodiversity in the lake.

· Nutrient cycling: Aquatic macrophytes help regulate nutrient cycles by taking up and storing nutrients like nitrogen and phosphorus, which can help prevent excessive algal growth and reduce the risk of harmful algal blooms.

· Sediment stabilization: The root systems of aquatic macrophytes help stabilize lake sediments, which can help reduce erosion and improve water clarity.

· Water filtration: These plants can help filter out pollutants and other contaminants from the water, improving water quality and reducing the risk of harmful effects on aquatic life and human health.

Overall, the presence of aquatic macrophytes in lakes can help promote a healthy and balanced ecosystem, especially in shallow lakes. However, excessive growth of these plants can also have negative impacts on lake use which can be a concern for lake users.

Macrophytes in the Jefferson German Chain of Lakes

A survey of the plant diversity in each of the lakes was conducted in 2009. Figure 10 – Figure 14 show the extent of curly leaf pondweed. Table 5 compares the lakes FQI values. An FQI value takes into account the vegetation found in the lake including its rarity or harmfulness to the ecosystem to create a comparable value between lakes. An FQI score of below 20 is indicative of degraded habitats. Despite Swede’s Bay having a large amount of Curly Leaf pond weed, many high value species were also found during the point intercept survey which increased the FQI score of Swede’s Bay. West Jefferson and Middle Jefferson have the worst FQI scores of the lakes in the chain. For the full summary of Aquatic Invasive Species in the Jefferson German Chain see Upper Cannon Lakes Excess Nutrient TMDL - Jefferson-German Lake Chain Pages 95-108.

While aquatic plants are vital to maintaining the ecologically-preferred clear water state, Figure 15, invasive species like Curly-leaf pondweed (CLP) can quickly alter the ecology of a shallow lake and prevent or restrict lake users from enjoying certain recreational activities such as boating and swimming. Senescence of Curly-leaf pondweed in mid-summer particularly contributes to internal nutrient loading and sub-optimal conditions for native aquatic plants, contributing to a turbid anoxic state. Therefore, the challenge for JGC lakes is to concurrently reduce CLP coverage and protect lake water quality by maintaining a clear-water, aquatic plant dominated state.

The image is a map showing West Jefferson Lake with markers for miles and symbols indicating the presence of Curlleaf and Pondweed.

AI-generated content may be incorrect.

Figure 10: West Jefferson Lake Curly Leaf Distribution May 2009.

The image depicts a map of Middle Jefferson Lake, highlighting the locations of Curlily Leaf and Pondweed as of May 2009, with no reported sightings (0) within 0.5 miles.

AI-generated content may be incorrect.

Figure 11: Middle Jefferson Lake Curly Leaf Distribution May 2009

The image is a map showing a distribution of pondweed in Swedes Bay in May 2009, with points indicating locations at intervals of 0.5 miles.

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Figure 12: Swede’s Bay Curly Leaf Pondweed Distribution May 2009

The image is a map of East Jefferson Lake with a colorful grid indicating various locations for curlyleaf pondweed, marked at intervals of 0.5 miles.

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Figure 13: East Jefferson Lake Curly Leaf Pondweed Distribution May 2009

The image depicts a map of a lake in Germany, marked with locations of curlyleaf pondweed, measured in miles.

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Figure 14: German Lake Curly Leaf Pondweed Distribution May 2009

Table 5: FQI Scores by lake

Lake	FQI Score May	FQI Score August
West Jefferson	9.82	12.02
Middle Jefferson	2.68	--
Swede’s Bay	15.75	20.51
East Jefferson	12.21	19.5
German	14.4	22.8

Figure 15. Cascading biological communities in shallow lakes under clear and turbid water states.

G. Riparian/shoreline Area

The lake riparian area, which refers to the zone of land adjacent to a lake, plays a crucial role in maintaining and influencing the quality of the lake ecosystem. Its impact is multifaceted:

· Water Quality Mitigation: The riparian area acts as a natural buffer zone, filtering and absorbing pollutants, sediments, and nutrients from runoff before they enter the lake. Plants in the riparian zone contribute to nutrient cycling by taking up excess nutrients like nitrogen and phosphorus from runoff. This can help prevent over-enrichment of the lake with nutrients, which can lead to issues like harmful algal blooms.

· Habitat and Biodiversity: Riparian zones provide important habitats for various plant and animal species. They offer food, shelter, and breeding sites for aquatic and terrestrial organisms, contributing to the overall biodiversity of the ecosystem.

· Bank Stabilization & Erosion Control: The roots of riparian plants help anchor the soil, preventing bank erosion and maintaining the structural integrity of the shoreline. This is particularly important during storms or high-water events. The vegetation in riparian areas, including trees, shrubs, and grasses, helps stabilize the soil along the shoreline. This prevents soil erosion and reduces sedimentation in the lake, which can negatively impact water quality and aquatic habitats.

Overall, the health and integrity of the lake riparian area are closely linked to the water quality and ecological balance of the lake itself. Proper management and conservation of these zones are essential for preserving the long-term health and sustainability of lake ecosystems. The state of the JGC shoreline has not been determined.

Figure 16. Loss of natural ground cover reduces infiltration and evapotranspiration, increasing stormwater and pollutant runoff into nearby waterbodies

4. Lake management goals

Goals for the future of Jefferson German Chain of Lakes were established with input from the GJGLA.

A. WATER QUALITY GOALS

The primary water quality goals are based on standards the State of Minnesota established for recreational use of lakes in the North Central Hardwood Forest Ecoregions. The presence of nuisance algae blooms is the primary basis for Minnesota recreational-use standards. The numeric criteria provided in the state standard are essentially proxies for the presence of algae or the conditions which lead to algal blooms. It is important to note that these standards apply to growing season measurements. Additional goals are included to address the primary sources of nutrient loading to the lake. The JGC goals are listed below:

1. Establish a monitoring program to evaluate water quality trends and improvements after management.

a. Three years of data should be collected to establish water quality trends and a baseline for pre-management conditions. See Section 6 for a detailed monitoring plan.

2. Meet the Minnesota’s standards (growing season averages) for each lake in order to remove from the impaired waters list.

3. Reduce the internal and external loads based on the TMDL and updated models, Table 6.

a. See Section 6 for an outline of the necessary feasibility study to address load reduction strategies.

Table 6: TMDL Load Reduction Summary.

Lake	Internal Load Reduction (lbs/yr)	External Load Reduction (lbs/yr)	Upstream Load (lbs/yr)	Total Load Reduction (lbs/yr)
West Jefferson	37	527	-	564
Middle Jefferson	756	1631	5	2,393
East Jefferson	20	1664	886	2,571
Swede's Bay	807	6424	-	7,231
German Lake	732	1078	159	1,969

4. Reduce the frequency and magnitude of seasonal algal blooms by 50% for 10 years after load reduction goals are met.

5. Support the Soil and Water Conservation District (SWCD) with their mission to implement agricultural best management practices (BMPs).

B. Aquatic invasive species GOALS

The aquatic invasive species (AIS) goals are based on controlling the resident populations of AIS and preventing the spread AIS amongst the chain of lakes.

1. Control the populations non-native aquatic invasive species.

a. See Section 3 above for specific species

2. Determine the existence and persistence of AIS in each lake

a. See Section 6 for more information on the recommended assessment.

3. Support local government programs regarding the public awareness of AIS efforts.

C. Habitat GOALS

1. Establish 75% shoreline as native habitats in shoreline, emergent, and submergent habitats to promote populations of natural mussels and other species that improve the lake ecosystem.

2. Establish the current condition of shoreline on each lake.

a. See Section 6 for information on the recommended assessment.

3. Educate and support local stakeholders about vegetation management best practices

a. See implementation section for information

D. recreation GOALS

1. Support safe and balanced recreational use of the lakes

5. Bathtub model update

A TMDL study completed in 2011 and published in 2014 by the Water Resources Center (WRC) at Minnesota State University, Mankato (MSU,M) on the JGC developed a BATHTUB model. This section outlines the updates that were incorporated from the original model. In general, we updated the information in the model to 2015-2024 date. Lake characteristics were kept the same as the TMDL. The Observed in-lake TP Concentrations were averaged for all available TP concentration values between 2015 and 2024. Data years available:

· West Jefferson: 2022

· Middle Jefferson: 2022, 2025

· East Jefferson: 2022, 2024, 2025

· German: 2022, 2024, 2025

· Swede’s Bay: No new data, so kept same as TMDL

The atmospheric load was 30 kg/km2-yr in TMDL, but we updated to 43.2 kg/km2-yr based on state database.

In TMDL, the P decay calibration factor was kept as 1, then internal loading factor was used to calibrate the model. For new data, we kept P decay calibration factor as 1, then scaled either the internal loading or watershed loading values or both from the TMDL values until observed matched predicted TP concentration:

· West Jefferson - Watershed is small, so it only calibrated with internal loading while keeping watershed loading the same.

· Middle Jefferson: Not possible to calibrate by reducing the watershed loading alone, so scaled both the watershed loading and internal loading from TMDL to match TP.

· East Jefferson: Added outflows from Swede’s Bay and Middle Jefferson together as the inflow to East Jefferson. Kept internal loading the same as TMDL, but scaled watershed loading from TMDL.

· German: Kept internal loading the same as TMDL, but scaled watershed loading from TMDL.

· Swede’s Bay: No new data on TP, but we increased atmospheric loading as mentioned previously, so scaled watershed loading from TMDL to compensate for the increase. Kept internal loading the same.

It is important to note that these models are based on limited data, and the internal load can be quantified by following the recommended feasibility study in Section 6.

The results of the phosphorus load budget from each lake can be seen in Figure 17 – Figure 21. Though the concentrations at the stream inputs are high, the primary driver for phosphorus levels in the lakes are ultimately internal loading. A large portion of the loading to East Jefferson Lake is through the outflow from Swede’s Bay as well. Swede’s Bay has phosphorus loads primarily driven by internal loading. Middle Jefferson Lake has a notable contribution of phosphorus load from the inflow but still is primarily driven by internal loading. The primary phosphorus load for West Jefferson is driven by internal loading. German Lake has phosphorus loads primarily driven by internal loading and Inflow site JG7 or S004-154.

The image illustrates a budget breakdown, showing the percentage contributions of precipitation load, local watershed, and internal load to the Total Maximum Daily Load (TMDL) for the year 2025.

AI-generated content may be incorrect.

Figure 17: West Jefferson Loading Summary

The image displays a bar chart illustrating budget percentages, with values ranging from 0 to 70, and categories such as precipitation, local load, internal load, and outflow, including a reference to TMDL for the year 2025.

AI-generated content may be incorrect.

Figure 18: Middle Jefferson Loading Summary

The image displays a bar chart comparing budget percentages, with categories for precipitation, local, internal load, middle, load, watershed, and outflow, specifically focusing on the outflow from Jefferson and the TMDL for the year 2025.

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Figure 19: East Jefferson Loading Summary

The image depicts a bar chart illustrating the distribution of budget percentages and precipitation levels across different sites within a watershed for the year 2025.

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Figure 20: Swede’s Bay Loading Summary

The image is a bar chart showing the distribution of budget percentages across different categories, including budget, precipitation, internal load, local load, and outflow, with a focus on the TMDL for the year 2025.

AI-generated content may be incorrect.

Figure 21: German Loading Summary

6. Implementation strategies

Table 7 shows the implementation plan to address the stated goals. There are four categories of the implementation strategies , eutrophication, Aquatic Invasive Species, habitat restoration, and recreation and safety. Table 7 also includes a timeline for the implementation activities and an associated estimated cost range. Each implementation strategy is further explained in the subsections below.

Table 7: Implementation Summary.

Timeline

Priority

2026

2027

2028

2029

2030

2031

2032

2033

2034

2035

Eutrophication

In-Lake Monitoring

High

$1,500-$2,000/year

Internal Load feasibility

High

$65,000-$75,000

Internal Load Control*

High

TBD

Education and Outreach*

Medium

AIS

AIS Macrophyte Assessment

Medium

$2,500-$5,000/lake

Education and Outreach*

High

Habitat

Shoreline assessment

Medium

$2,000-$3,500/lake

Education and Outreach*

High

Recreation and Safety

Boat Capacity Survey

Low

$3,500-$5,000/lake

Outreach for Wake Boats**

Medium

Outreach for Safe boating **

High

*The cost of the Internal load control will be determined by the Internal load feasibility study.

**Outreach activities can be determined by the outreach and education plan

A. Eutrophication

Monitoring Plan

The first goal for eutrophication is to establish a monitoring program to evaluate water quality baseline and improvements after management.

In-lake sampling of JGC lakes have been done sporadically over the years. The following monitoring plan is recommended to set baseline conditions. The monitoring plan is built from past data sets and models. EOR recommends the GJGLA complete this plan for three consecutive years pre-in-lake treatment to meet the goal.

The recommended monitoring plan is outlined in Table 8, below. The monitoring locations are illustrated in Figure 22. The in-lake monitoring includes dissolved oxygen and temperature profiles and routine water quality monitoring. The dissolved oxygen and temperature profiles will inform mixing conditions and anoxia within JGC lakes. The routine water quality monitoring at the deep hole will inform temporal dynamics of mixing, nutrients, algae growth, and water clarity.

There has been no long-term monitoring of the water flowing from Swede’s Bay to East Jefferson. This information is important for prioritizing management activities amongst the chain. For example, Swede’s Bay may be acting a sink of phosphorus from the watershed load but may be acting as a source of phosphorus downstream because of high internal load. Monitoring at the Swede’s Bay outlet will allow us to determine the load from Swede’s Bay downstream.

The cost range for this monitoring plan is $1,500-$2,000/year incorporating the cost of equipment rental (DO and temperature probe) and lab costs for data analysis. The cost of the monitoring relies on volunteers to collect the data. If volunteers cannot be used then the cost will increase.

Table 8: Recommended Monitoring Plan Summary

Parameter	Timing	Frequency	Monitoring Depth	Station Location	Methodology
Swede’s Bay outlet Monitoring
Flow	May-October	Continuous	_	Swede’s Bay outlet	Flow meter
React P, Total P	May-October	Biweekly	Surface outflow	Swede’s Bay outlet	Samples will need to be shipped to a certified lab for analysis
In-lake Monitoring
Dissolved Oxygen (DO) and Temperature Profiles	May-October	Biweekly	Every 0.5m from surface to bottom	In lake Sampling: Deep-hole	Multi-probe
React P, Total P	May-October	Biweekly	0.5 ft from the bottom and at the surface		Grab samples collected using a van dorne sampler. Samples will need to be shipped to a certified lab for analysis
Chlorophyll-a	May-October	Biweekly	Surface		Samples will need to be shipped to a certified lab for analysis
Secchi Depth	May-October	Biweekly			Secchi Disk

Internal Load Feasibility Study

Eutrophication goals 2-4 all relate to meeting nutrient reductions goals to reverse eutrophication on the JGC lakes. The driving phosphorus load on each lake is internal load. A feasibility study for internal loading on each lake must be conducted to determine the appropriate management. If an alum treatment were recommended, the prescribed dose could reduce the internal load by up to 90% and last at least 10 years.

Since most of the lakes have internal load as the majority load. The next step is internal load feasibility study. This includes understanding the sediments and the oxygen and mixing dynamics collected from the recommended monitoring plan above. The sediment cores will be collected at locations at varying depths, as indicated in Figure 23-Figure 27. The sediment cores will be collected to quantify the phosphorus content and potential phosphorus release from the sediments into the water column which is used to quantify the internal load. The sediment cores will also be used to prescribe a sediment inactivation plan if internal loading control is deemed necessary.

Sediment cores should be taken from areas of anoxia or areas that are feasible for sediment activation application. The recommended locations can be further refined based on the results of the DO monitoring. The convention for selecting the locations of the sediment core was determined by the lake bathymetry and morphology. More complex lakes require more sediment core locations to resolve internal load dynamics. Sediment cores should be segmented into six sections: 0-2cm, 2-4cm, 4-6cm, 6-8cm, 8-10cm, 10-20cm. Each section should be analyzed for loosely bound P, iron-bound P, labile organic P, and aluminum-bound P. The phosphorus content is used to prescribe the internal load control dose. In addition, sediment core will be analyzed for soluble reactive phosphorus release rates. Incorporating release rate analysis is imperative to understanding the internal load. The P release rate in conjunction with the DO data will be used to update the internal load estimate.

Table 9: Recommended Sediment Core Summary

Lake Sediment Cores	No. cores fractionation	No. cores flux	Cost
East Jefferson Lake	8	3	$14,500
Middle Jefferson Lake	3	3	$6,750
West Jefferson Lake	4	3	$8,250
Swede's Bay	4	4	$9,000
German Lake	6	3	$11,500

The cost of the internal load feasibility study includes $50,000 of laboratory costs for sediment core analysis plus an additional $15,000-$25,000 in consultant fees to analyze data, update the P budget, and create an internal loading control plan. The total cost of this feasibility study is $65,000-$75,000.

Agricultural BMPs

The fifth eutrophication goal is to support the Soil and Water Conservation District (SWCD) with their mission to implement agricultural best management practices.

A wide array of conservation practices is available to manage nutrient loading from agricultural land. Roughly 20% of the Jefferson German Chain watershed is currently used for row crop production and another 20% for pastureland. Agricultural conservation practices that promote soil health are recommended for the Jefferson German Chain watershed. Soil health practices are a set of sustainable farming techniques and management strategies designed to protect and improve the overall health and quality of soil in agricultural ecosystems. These practices aim to enhance soil fertility, structure, and resilience, while minimizing erosion, nutrient depletion, and environmental degradation. They are critical for maintaining long-term agricultural productivity and sustainability. In many cases, these practices are cost-neutral (reduce expenses) and may be eligible for funding through the Le Sueur Soil and Water Conservation District cost share program.

Cover Crops

Cover crop is a term to describe any crop grown primarily for the benefit of the soil rather than the crop yield. Cover crops are typically grasses or legumes (planted in the fall between harvest and planting of spring crops) but may be comprised of other green plants. Cover crops prevent erosion, improve the physical and biological properties of soil, supply nutrients, suppress weeds, improve the availability of soil water, and break pest cycles, in addition to a wide range of additional benefits. The Le Sueur SWCD offers cost share programs for agricultural BMPs, and Cover Crops are currently being incentivized at a rate of $45/acre for single species and $50/acre for multispecies.

No-till

No-till is a way of growing crops or pasture from year to year without disturbing the soil through tillage. No-till increases the amount of water that infiltrates into the soil, the soil's retention of organic matter and its cycling of nutrients. It can also reduce soil erosion and increase the amount and variety of life in and on the soil. The most powerful benefit of no-tillage is improvement in soil biological fertility, making soils more resilient. The Le Sueur SWCD offers cost share programs for agricultural BMPs and No-till is currently being incentivized at a rate of $20/acre.

4Rs of Nutrient Management

The 4Rs of nutrient management refer to fertilizer application techniques focused on minimizing the risk of nutrient loss from the field. The principles of the 4R framework include:

• Right Source – Ensure a balanced supply of essential nutrients, considering both naturally available sources and characteristics of specific products in plant available forms.

• Right Rate – Assess and make decisions based on soil nutrient supply and plant demand.

• Right Time – Assess and make decisions based on the dynamics of crop uptake, soil supply, nutrient loss risks, and field operation logistics.

• Right Place – Address root-soil dynamics and nutrient movement and manage spatial variability within the field to meet site-specific crop needs and limit potential losses from the field. Nutrient management plans are tailored by farmers and/or crop consultants to maximize yields and minimize nutrient inputs.

B. Aquatic invasive species Management

The ultimate AIS goals is to control the populations non-native aquatic invasive species. The first step in controlling AIS is to determine the existence and persistence of AIS in each lake via a diagnostic study.

The diagnostic study determines the health of the aquatic vegetation community. The monitoring plan includes point intercept surveys and delineation of aquatic invasive species (AIS). Point-Intercept surveys include systematic assessment of the vegetation community over time. The point-intercept method is considered the standard protocol by MNDNR for sampling macrophytes because it offers a methodology that is quantitative (e.g., frequency of occurrence), repeatable (can be used to track trends in aquatic plant communities over time), and georeferenced (can be used to compare plant communities within different areas of a lake). A small lake should include 60-80 sampling points in the littoral zone. For larger lakes, a 100 x 100 meter point-intercept sampling grid over the total surface area of the lake is recommended. It is assumed that there will be up to approximately 300 sampling points in the littoral zone. At each sampling point the aquatic plants and plant density for each species are identified. The survey will yield the distribution, density, and floristic quality of the aquatic plant community. A Floristic Quality Index (FQI) will also be calculated for each survey. The FQI calculation is based on both the quantity of species observed (species richness) as well as the quality of each individual species. Another monitoring method, specific to AIS, is to precisely delineate the total acreage infested with AIS. The timeline for these surveys is dependent on species. The estimated cost for the survey includes labor for the survey and data analysis of $2,500-$5,000 per lake.

The final goal is to support existing governmental programs AIS education and outreach programs and to put signs up by lake entrances. Further discussion about partnerships and outreach activities in sections below.

C. habitat

Lakeshore improvements

The ultimate habitat goal is to establish 75% of native shorelines. However, at this time, the current shoreline status has yet to be determined for each lake.

The zone of land adjacent to a lake's shoreline or lake riparian area plays a crucial role in maintaining and influencing the quality of the lake ecosystem. In particular, the riparian area acts as a natural buffer zone, filtering and absorbing pollutants, sediments, and nutrients from runoff before they enter the lake. Plants in the riparian zone contribute to nutrient cycling by taking up excess nutrients like nitrogen and phosphorus from runoff.

Lakeshore improvements entail planting of native vegetation along lakeshore and in emergent zone of the lake as a way of restoring the natural transition from lake to upland. The goal of a lakeshore improvement effort is a dense stand of vegetation growing throughout the riparian area to trap and filter pollutants. Beyond addressing water quality, lakeshore improvements provide additional ecosystem services such as habitat for birds, spawning and refuge for fish, wave-erosion protection, and pollinator habitat.

To assess the current condition of the shoreline and identify areas for shoreline improvements, a diagnostic study is recommended. The diagnostic study determines extent of shoreline erosion along the lake. The monitoring plan includes targeting areas from visual lakeshore survey using Score Your Shore (Department of Natural Resources). Score Your Shore is a tool to assess habitat conditions. The protocol is designed for use by lakeshore property owners to self-assess habitat or by organizations, such as lake associations and county staff, to assess multiple sites on a lake. Score Your Shore provides an objective and systematic method to assess the type, quantity, and quality of the existing shoreland habitat.

The Score Your Shore tool will enable you to:

· Assess the amount of habitat at developed lake sites

· Generate awareness of what makes a high quality functioning shoreline buffer

· Provide a system to recognize landowners with functioning shoreline buffers.

The cost for the shoreline assessment study is estimated to be $2,000-$3,500 per lake. The cost to complete the diagnostic study includes conducting lakeshore surveys, i.e., Score Your Shore.

The Cannon River Watershed JPO offers shoreland owners $500 per parcel for planting a minimum of 150 sq ft of native vegetation. This program should be promoted to shoreline owners as part the lake association outreach programing

D. recreation and safety

The goal for recreation and safety is to support safe and balanced recreational use of the lakes. In order to achieve this goal, it is important to determine the safe boat capacity for each lake.

The diagnostic study for recreation and safety includes evaluating the lakes’ boating carrying capactiy. The boating carrying capacity is the number of watercaraft that can simultaneously operate on the lake without: compromising user safety, causing significant user displacement or dissatisfaction, and causing environmental harm to the lake. The methodology for the boat capacity survey includes the following steps:

Calculate usable lake area that supports a range of boating activities and speeds safety without significant environmental impact.
Establish minimum spatial requirements for various boating activities/speeds
Conduct census of watercraft during peak periods of lake use and relative proportions of watercraft engaged in different activities/speeds
Choose optimum boating density
Compare actual use of the lake to estimated carrying capacity.

The monitoring plan includes identifying boats type and density and number of Boat slips over 6 days, selecting 3 peaks days, 1 average day, and 2 non-peak days.

The estimated cost for the completing the boat carrying capacity survey is $3,500-$5,000 per lake. The cost to complete the diagnostic study includes labor for the boat capacity survey.

The outreach goals for wake boating can be achieved by educating boaters on safe practices. Wake Boating is only safe in 20ft of water and 500ft from shore. Only a small portion of East Jefferson and German fall into this Category. To help residents and visitors to understand, consider posting on social media, educating at meetings, and creating signs for boat launches with information around wake boat safety and environmental impact. Possible partnerships for this work include MN Coalition of Lake Associations and Minnesota Lakes and Rivers.

E. Education and outreach

Each implementation category includes an education and outreach component. EOR recommends developing a separate education and outreach plan to broadly address the comprehensive program. The following activities are important to consider for education and outreach programing.

· Consider joining MN Cola ($50/annual)

· Create subcommittees

· Promote on Social media

· Dedicate time during meetings for rotating topics

· Engage with business on the lakes

· Give materials to AIS inspectors

These efforts will require a pool of volunteers for consider engaging with your membership to participate in Citizen science, subcommittees, and boat surveys. GJGLA should explore partnerships with area organizations to provide education and outreach for each area of interest. The recommended partnerships per implementation item is summarized in Table 10. The following partnerships will be important for education content to provide to members and function as guest speakers.

Table 11: Grant Summary

Eutrophication		Priority	Grant	Level of support	Funder	Timeline
	In-Lake Monitoring	High	Surface Water Assessment	TBD	MPCA	2027
	Internal Load feasibility	High	Surface Water Assessment	TBD	MPCA	2027
	Internal Load feasibility	High	Clean Water Fund: Project and Program	10% match required	BWSR	2027
	Internal load control	High	Clean Water Fund: Accelerated Implementation	10% match required	BWSR	2027
	Education and Outreach
AIS
	Macrophyte AIS Assessment and Control	High	Invasive Species Control	fund control of CLP, EAW, or flowering rush	MN DNR	February Annually
	Education and Outreach	High
Habitat
	Shoreline assessment	Medium	Native Planting Cost Share	$500/ landowner	Canon River JPO	Rolling
	Shoreline improvements	Medium	Land Conservation Grant	$360,000 Typically 3-5 projects funded annually	Midwest Glacial Lakes Partnership	First of the Year Annually
			Bass Pro Shops US Open Grant Program	no limit or match	National Fish Habitat Partnership	May Annually
			Partners for Fish and Wildlife Program	$25,000, no match required	US Fish and Wildlife Service

	Education and Outreach	High
Recreation and Safety
	Boat Capacity Survey	Low
	Outreach for Wake Boats	High
	Outreach for Safe boating	High

1. Introduction

2. Background

A. Watershed Landuse

B. Hydrography

Swede’s Bay Subwatersheds

West Jefferson Subwatershed

Middle Jefferson Subwatershed

East Jefferson Subwatershed

German Subwatersheds

3. State of the Lakes

A. Nutrient Cycling in Lakes

External Load

Internal Loading

B. Phytoplankton & Algae

C. regulatory Setting

D. Lake Monitoring

E. Tributary Monitoring

F. Aquatic Macrophytes

Macrophytes in the Jefferson German Chain of Lakes

G. Riparian/shoreline Area

4. Lake management goals

A. WATER QUALITY GOALS

B. Aquatic invasive species GOALS

C. Habitat GOALS

D. recreation GOALS

5. Bathtub model update

6. Implementation strategies

A. Eutrophication

Monitoring Plan

Internal Load Feasibility Study

Agricultural BMPs

B. Aquatic invasive species Management

C. habitat

Lakeshore improvements

D. recreation and safety

E. Education and outreach

7. Grants Funding

8. Conclusions and Recommendations

		Priority	Lead Organization	Partners
Eutrophication
	In-Lake Monitoring	High	GJGLA	SWCD
	Internal Load feasibility	High	Consultant
	Internal Load Control	High	Consultant
	Education and Outreach	Medium
AIS
	AIS Macrophyte Assessment	Medium	GJGLA	AIS inspectors
	Education and Outreach	High	GJGLA	MN COLA, MAISRC
Habitat
	Shoreline assessment	Medium	Consultant
	Education and Outreach	High	GJGLA	MN COLA, University Partners, Canon River Watershed
Recreation and Safety
	Boat Capacity Survey	Low	Consultant	DNR
	Outreach for Wake Boats	Medium	GJGLA	MN COLA, County, Minnesota Lakes, and Rivers
	Outreach for Safe boating	High	GJGLA	MN COLA, County, DNR