Lake Improvement Plan

This page is dedicated to our Lake Improvement Plan.  We've included a WEB and PDF version of the full plan, as well as an executive summery. 

This page will be updated with additional details, volunteer opportunities, etc., so be sure to check back.

Full Plan

- Web Version -  Downloadable MS Word Version -

Executive Summary

The Jefferson German Chain (JGC)—West Jefferson, Middle Jefferson, East Jefferson, Swede’s Bay, and German Lakes—does not meet Minnesota water quality standards due to elevated nutrients and recurring nuisance algae blooms. The lakes were listed as impaired for nutrients in 2008 and remain impaired based on the most recent assessments (2022–2025). This Lake Management Plan (LMP), prepared for the Greater Jefferson German Lakes Association (GJGLA), updates conditions since the 2014 Upper Cannon Lakes Excess Nutrient TMDL and provides a practical roadmap to improve water quality, manage aquatic invasive species (AIS), restore shoreline habitat, and support safe recreation.

·Current condition: Total phosphorus (TP) concentrations across the chain are above applicable standards; Swede’s Bay is consistently the highest-TP basin, while German Lake generally shows the lowest TP within the chain but still exceeds standards.

·Primary drivers: Updated phosphorus budgets indicate internal loading (legacy phosphorus stored in sediments and released under low-oxygen or disturbance conditions) is a dominant driver in multiple basins, with additional contributions from watershed runoff and upstream inflows (notably Swede’s Bay influences downstream East Jefferson).

·Watershed context: Sub watersheds range roughly from 7%–23% developed and 26%–63% agricultural. Agricultural land and altered tributaries/buffers contribute to external nutrient loading, and several tributary monitoring locations show very high TP concentrations.

·Aquatic vegetation: Historic surveys document extensive curly-leaf pondweed (CLP) in parts of the system. CLP senescence can add to internal nutrient cycling and degrade late-season conditions.

Management goals (as developed with GJGLA) focus on: (1) establishing consistent monitoring to quantify trends and track improvements; (2) achieving Minnesota growing-season standards to support delisting for nutrients; (3) reducing internal and external phosphorus loads consistent with the TMDL framework and updated modeling; (4) reducing the frequency and magnitude of seasonal algal blooms over the long term; (5) controlling AIS populations and preventing spread; (6) increasing native shoreline habitat coverage; and (7) supporting safe and balanced recreational use.

Recommended near-term priorities (next 1–3 years) are designed to reduce uncertainty, target investments, and position GJGLA for grant funding:

Implement a consistent in-lake monitoring program(May–October) across the chain, including biweekly Secchi depth, chlorophyll-a, and TP, plus dissolved oxygen/temperature profiles to document mixing and anoxia. Estimated cost: ~$1,500–$2,000 per year (assuming volunteer sampling).

Monitor Swede’s Bay outflow to quantify downstream loading to East Jefferson and refine prioritization of management actions across the chain.

Complete an internal load feasibility study(sediment phosphorus fractionation and release rates, supported by DO data) to quantify internal loading and evaluate sediment inactivation options (e.g., alum) and expected longevity. Estimated cost: ~$65,000–$75,000.

Support agricultural best management practices (BMPs)with partners (e.g., SWCD) to reduce external loading (e.g., cover crops, no-till, and 4R nutrient management) in high-contributing sub watersheds.

Conduct AIS and habitat diagnostic assessments to establish baselines for action and success tracking (macrophyte point-intercept/AIS delineation; shoreline condition assessment such as “Score Your Shore”). Estimated costs: AIS survey ~$2,500–$5,000 per lake; shoreline assessment ~$2,000–$3,500 per lake.

Expected outcomes of implementing this plan include clearer, more stable recreational conditions (improved water clarity, fewer nuisance blooms), measurable reductions in phosphorus loads (especially through internal load controls informed by feasibility testing), and improved habitat resiliency through shoreline restoration and AIS management. Funding strategy: GJGLA should coordinate closely with the Cannon River Watershed Joint Powers Organization to align priority projects with One Watershed One Plan updates and to strengthen competitiveness for MPCA/BWSR and other grant programs. Progress should be reviewed annually using the monitoring data to adaptively refine project sequencing and investment levels.