Silting: Sand does not stay put. Every footstep on the beach pushes it downhill towards the water and it drifts with the current and wind. When the lake is lowered, sand leaves the beaches and flows with the water toward the middle where it can settle or be carried downstream. Exposed sand blows from one spot to another, moves with rain and snow melt and ends up where it’s not intended. Sand that doesn’t drift away eventually works its way into the lake bottom, but even though we may not see it, it’s still in the lake. The sand we add contributes to silting-in, making the lake shallower, and at the same time requiring on-going beach maintenance –just add more sand! Shallow water is warmer, supports algae growth and is lower in oxygen, conditions that are detrimental to our fish. While silting is a geologic process that happens naturally over time, adding beach sand to the natural sediment load hastens this aging and filling-in process. Water clarity: Beach sand is different from native lake bed soil. Because sand drifts easily in water, it clouds it, preventing UV light from disinfecting bacteria in the lake- a natural process that is necessary for maintaining good water quality. As rainwater and snowmelt run over the beach they pick up this silt, it goes into suspension in the lake, and can be transported significant distances. The smallest/lightest particles are the last to settle, and thus the first to be stirred up by aquatic animals, humans or even wind fetch induced currents or the annual temperature induced turnover. Reduced clarity correlates to reduced visibility, and a reduction in disinfection of pathogens by ultraviolet light and in studied cases, increases in presence of microbial pathogens. In addition, a study done in York County, Me. found that a decline in lake water clarity caused a noticeable decrease in the value of surrounding homes. Biological Impact: Deposited sand has major biological impacts on the lake ecology. Sand deposited and drifted along the shore and lake bottom can smother bottom-dwelling algae and invertebrates, reduce the amount of aquatic and shoreline habitat for fish and crayfish, destroy spawning and nesting sites for reptiles and amphibians, and disrupt the food chain.
We all love our “special place on the lake”. Most of us want that perfect beach. We wonder why there is a lot vegetation growing. We hate to step or swim through those gross weeds. Have you noticed more algae in your lake? It seems efforts educating lake property owners about sand placement on beaches over the years has been falling on some deaf ears. I and countless other volunteers have spent over 15 years volunteering to keep our lake usable and managing the milfoil program, it makes my heart sink when I see a “new beach”. We all want the “perfect sandy beach”. Now just imagine if we all had sandy beaches. The shorelines would look all the same and we would not enjoy the views we enjoy today. BUT aesthetics is on the bottom of the list! Sandy beaches incrementally create accumulated impacts and change the chemistry, clarity and character of the lake. The ecosystem is challenged. Some have used sand for decades to build and replenish the beaches, it is now recognized that sand can have a negative impact on the water quality and overall health of the lake. The undesirable effects to watch for are algae blooms, decrease in lake depth, lower narrows fill, loss of fish habitat and apparent decline in fish population. While sand is not the only cause of these problems, it is the easiest one for us to control – simply by not adding any more of it to the lake. How Sand Can Affect the Health of Our Lake Silting - Water Clarity - Biological Impact - Chemical Impact - OPTIONS