The following educational resources below are available for further learning on inland lake management and restoration and lake issues.
What Defines a Sustainable Lake?
A Sustainable Lake will have the following characteristics:
- Long-term objectives that relate to improvement goals
- Implementation of technologies and methods that are “in sync” with nature
- An enhanced capacity to deal with “shocks” or disturbances that can offset the ecosystem balance
- An overall goal of conservation which requires a deep understanding of all aspects of the lake resource
- An active community that understands both the lake AND how they interact with it
- The ability to thrive without constant financial inputs or at least with minimal inputs over time
- A consistent pattern in water quality without further degradation or lowered trophic status
Common Problem #1: NPS Pollution
Non point source pollution (NPS) is the pollution caused when climatic events carry pollutants off of the land and into lakes, streams, wetlands, and other water bodies (Michigan Department of Environmental Quality). Unlike point source pollution which is derived from distinctive discharge pipes, NPS pollution is often diffuse in nature. The diffusivity of NPS pollution creates challenges in determining the location of pollution sources which makes mitigation (treatments) a difficult and sometimes impossible task. NPS pollution is regulated by statute and includes categories such as agricultural source runoff and confined animal feed operations (CAFO’s), small urban runoff (populations with < 100,000 residents), urban stormwater runoff from unsewered areas, septic tanks, runoff from abandoned mines, land disturbing activities, and atmospheric deposition. Although regulation exists, it is difficult to regulate NPS pollution at both the federal and local levels. There has been considerable debate among scientists, engineers, and other stakeholders regarding the most effective scale for reduction of NPS pollutants. The NPS pollutants of greatest concern to local waterways include nutrients such as nitrogen and phosphorus, sediment, toxic compounds, and pathogens (E. coli, among many others). The Water National Quality Inventory (1994) ranked the leading sources of water quality impairment to lakes as primarily agriculture, secondarily municipal point sources, and thirdly, urban runoff.
Common Problem #2: Hybrid Watermilfoil
Hybrid milfoil is a serious problem in Michigan inland lakes. A similar milfoil species that is considered to be exotic by some scientists (Myriophyllum heterophyllum) in New Hampshire was found to have significant impacts on waterfront property values (Halstead et al., 2003). Moody and Les (2007) were among the first to determine a means of genotypic and phenotypic identification of the hybrid milfoil variant and further warned of the potential difficulties in the management of hybrids relative to the parental genotypes. It is commonly known that hybrid vigor is likely due to increased ecological tolerances relative to parental genotypes (Anderson 1948), which would give hybrid milfoil a distinct advantage to earlier growth, faster growth rates, and increased robustness in harsh environmental conditions. Furthermore, the required dose of 2,4-D for successful control of the hybrid milfoil is likely to be higher since there is much more water volume at greater depths it can occupy and also due to the fact that hybrid milfoil has shown increased tolerance to traditionally used doses of systemic aquatic herbicides. There has been significant scientific debate in the aquatic plant management community regarding the required doses for effective control of hybrid milfoil. Glomski and Netherland (2010) found that the greatest percentage of hybrid milfoil (93-100%) was successfully killed with 2,4-D concentrations greater than or equal to 70 µg/L. Their results may vary dramatically from open-water systems; however, as they were tested in laboratory aquaria and the results in field trials would be subjected to a multitude of external environmental factors. However, the concentration of 70 µg/L yielded a desired 2,4-D residue concentration to be maintained for up to 21 days as in the study by Glomski and Netherland (2010). Thus, residue sampling intervals could be recommended at the treatment areas for 2 hours after treatment, 1 week after treatment, and 20 days post-treatment. Concentration-Exposure Time (CET) studies such as those by Glomski and Netherland (2010) and Poovey et al., (2007) are important in the determination of dose requirements for hybrid milfoil; however, they were conducted in laboratory aquaria and field CET studies are therefore needed.