Why isn't the Lake as clear as it used to be?

[ushaggerb]

I was talking to my sister, who hasn't been to the Lake since she was a child. She was reminiscing about the rocks out in front of the dock, how you could see the sparkle off the rocks.

I said that I couldn't see them anymore; in fact, a lot of the rock "landmarks" around our old cottage are now difficult to pick out.

Does anyone know what has caused the difference in the Lake visibility comparing today with the late 70's?

[trfour]

As time goes on, my eyesight has diminished... I would not go so far as to blame it on the Lakes Clearwater's though...

Welcome to the forum ushaggerb!!

Terry
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[RailroadJoe]

Ever hear of engine oil. Look at the color of the rocks, even at Rye or Hampton Beach. Rocks that were always whitish are now blackish. Happens all over.

[Slickcraft]

Overall the lake is still very clear but at times shallow bays do have reduced viability due to microscopic plant abundance such as algae. That microscopic plant abundance is directly related to available nutrients or total phosphorus concentrations in the water.

Over many years the phosphorous levels have slowly crept up and storm runoff can create temporary conditions of reduced clarity. This is directly related to use of lawn fertilizer near the lake and the remaining sub-standard septic systems.

We are volunteers in the NH Lakes Lay Monitoring Program where water samples are taken from both shallow and deep sites on a weekly basis and then analyzed at the UNH Center for Freshwater Biology. Also we measure clarity on site by measuring the Secchi Disk depth, how far down we can still see the disk.
http://en.wikipedia.org/wiki/Secchi_disk

In Saunders Bay in 2010 the average Secchi Disk depth was 9.6 meters (31.5 feet) with a range of 9.3 to 10.6 meters (30.5 to 34.8 feet). My direct experience was that the reduced depths were in days when the water had visible particles of green plant life.

The 2010 report will be available on the Winni Gateway site shortly.
http://winnipesaukeegateway.org/monitoring-the-lake/introduction/

[Lakegeezer]

Reduced clarity in the lake is due to organic matter; mostly algae grows that supports bugs. If you swim in the lake and let your hair dry, you'll notice it gets stiff, as if you put hairspray in it.

Some parts of the lake are less clear than others, but overall, the lake is much less clear than it was 100 years ago, before the rapid development along the shore and within the watershed. Phosphorus is the main problem. Phosphorus levels are higher than if the area had been left in its natural state. It is the miracle grow plant food for aquatic plants and other organisms.

As overfed levels of organic matter dies, bacteria levels grow too, causing decay, and overwhelming sandy lake bottoms with muck. The ecosystem, such as fresh-water clams, stop cleaning the bottom when there is too much muck. Where the natural cleaning process stops, the sparkling bottom is gone. Those with sandy bottoms (in the lake I mean :eek:) today should feel a sense of responsibility to keep it that way. I've gotten involved, because I've seen several of my favorite spots go from sandy to mucky over 20 years.

The folks at Lakes Region Planning Commission (LRPC) and Lake Winnipesaukee Watershed Association (LWWA) have determined through modeling that phosphorus levels would be about 4 parts per billion (ppb) today, if there were no development. Instead, levels range from 6 to over 20 ppb. Anything over 8 ppb is considered impaired water by the state and when it gets over 12, we start getting summer algae blooms and the dreaded cyanobacteria problems. All lakes get old. Ours is just getting old faster than the rate of 100 years ago. Its called anthropogenic eutrophication - Lake aging caused by humans.

Local and state governments are doing research and trying to slow down the process through new regulations. For example, we are not allowed to have detergents with phosphorus any more. Phosphorus fertilizer is not allowed on lawns close to the shoreline. The shoreline protection act was created to minimize disturbing ground near shore. Steep slope regulations help stop building that will cause erosion. But, recent budget cuts have slowed down the government's work, including enforcement. The current recession may be slowing things down more than regulations, as less building is going on and more second homes go unoccupied.

Education is the easiest, cheapest and most effective in slowing the deterioration of the lake. If everyone in the watershed acts with conservation in mind, the accumulative effect will be the greatest.

For more information, or ideally - to get involved, check out the local web site: http://winnipesaukeegateway.org/ If anything will help clean up the lake, its the work the folks behind that web site are doing and the hundreds of volunteers that put their time and energy into this problem.

[songkrai]

Long ago.

There were less houses and less boats.

Very few green lawns and no one I knew actually fertilzed the lawns.

We used to harvest crawfish and sell at bait shop in Meredith. I don't see any crawfish anymore.

There used to be many mussels. Don't see too many anymore.

Developments such as the one Peter Kraine constructed didn't do the lake much help.

Day boats come and go. Who knows what is on the bottom of those boats.

The lake is fed from the north. Other lakes and streams feed the lake. Who knows what is arriving up stream.

[CTYankee]

"If you swim in the lake and let your hair dry, you'll notice it gets stiff, as if you put hairspray in it."

Ah yes; I remember this, with fondness, when I had hair myself. :(