9069-R4_ML&P_LSLA_2024_SummerNewsletter_Web

Water Quality: Healthy but Fragile Janet Slack

and plant activity. This is especially impactful in the shallow coves of the lake where water temperatures can increase even further. We can expect to see more algae with higher temperatures. The stratification of the lake now occurs earlier in the season than is healthy and therefore lasts much longer. This simply adds more stress to the lake system and all the organisms in it. This earlier and stronger stratification in the lake increases fragility as well. Finally, there is much less natural shoreline on the lake than in years past. New construction, removal of native plants and changes to the landscape in both the shoreline and in the watershed increase lake fragility. So far, we have avoided dramatic drops in water quality that many Maine lakes have experienced in the past several years. Except for a large, smelly algae overgrowth in May 2024 that lasted several days, we have been fortunate. Many nearby lakes are struggling with the problems we want to avoid - algae blooms, fish kills, unpleasant odors and water that is unappealing for recreational uses. Of course, these problems also mean decreased property values and expensive corrective actions if there are any that can be done. What this means Little Sebago Lake officially has the status of “threatened” and so the lake is highly sensitive to any phosphorus additions. Many of the ways that phosphorus is added to the lake are out of our control – runoff from violent storms, increasing lake temperatures and dropping oxygen levels. It is more important now than ever that we help the lake maintain resilience by limiting any phosphorus we can. The hard work that many lakefront property owners do to keep their property from negatively impacting the lake is paying off. Are you LakeSmart? If you have had your property reviewed share the findings with your neighbors and take the actions that were recommended. If you have not had your analysis done sign-up today, the health of our lake depends on it. LakeSmart recommendations are nonbinding, and the reports are yours with ideas and assistance in correcting problems. What can you do to protect & improve our water quality? All the little things add up… • Don’t pee in the lake, • Keep dead plant matter out of the water, • Pick up all animal waste (wear masks and gloves if dealing with bird waste), • Pump septic tanks 2-4 years and • Never, never use soap or any chemical products in or near the water

First the good news… L ittle Sebago water quality continues to be in the healthy range. Water clarity is good and has been relatively steady for 30 years. Oxygen levels are appropriate except for the deepest parts of the lake in late summer. We have tested for phosphorus for four summers and our numbers are mostly within acceptable ranges .The streams running into the lake are often below the allowable limits of phosphorus as well. Here is what a healthy lake looks like – • High clarity of the water, • Wide variety of plants, fish, and aquatic organisms, • Moderate levels of algae, • Oxygen extending deep into the lake, • Stratification starting in mid-summer and ending with fall turnover, • Low levels of phosphorus, • Natural shoreline that protects and prevents erosion The Ways Our Lake is Fragile Did you notice that in the section above that there were lots of qualifying words: “mostly,” “often,” “except” and “relatively”? While things are now acceptable, we no longer have the safety cushion of the past. Sometimes our results are above the limits and some of the healthy characteristics of a lake no longer apply to Little Sebago. Our testing over the past few years and the recent analyses of 30 years of historical data have helped us better understand the ways Little Sebago is fragile. The first sign of fragility is that there is significantly less oxygen available at the bottom of the middle basin than in the past and that this low oxygen level happens earlier in the season. Our recent testing shows a similar pattern may be developing in the upper and lower basins. The lack of oxygen creates stress for our bottom-loving fish, like trout, which need cold water, but also need to breathe. The fish are being forced up from the depths of the lake until at some depth, the water is too warm to sustain them. Another problem with lack of oxygen is that it creates a condition that can add phosphorus to the lake. Ordinarily, the bottom sediments of the lake contain phosphorus that is bound up with other chemicals and does not cause problems. However, when the water goes anoxic (low oxygen), chemical bonds in the sediment can be broken releasing phosphorus back into the water. This added phosphorus can be food for algae as it gets mixed into the higher layers of the lake. Increasing water temperature is another sign of fragility. Warmer water at the surface of the lake means that there is more algae

Spring 2025 | LittleSebagoLake.com 27