Lake Quality | June 2016

Property Owner to Property Owner: Great Expectations for Lake
Heritage, Round 2
John Doerr and Matt Verdirame

I was excited when I returned from my southern overwintering site to Lake Heritage and noticed right away that from my dock I could see the bottom of the lake about 6 feet out.  While I’ve seen some fairly clear water over the years, I really think this was the best yet.  So I reminded myself, “John, don’t get overly enthused just now.  The quality won’t stay that way all summer!”  And I was reminded it was time for an update to the article we did last fall on the overall quality of the lake.  What should we look for this season?

table 01

I’m not a water quality expert, but reducing sediment organic matter 60-70% in less than one year sounds pretty good.  We are also very happy with the results of the phosphorus tests!  Nitrogen and phosphorus drive the huge algal blooms we’ve been experiencing; they need that phosphorus to get a leg up.  The test data shows the same period reductions of over 80% in total phosphorus.  Now, don’t ask me what happened to the ski run sample (April 21 data, second table), but if I were king, I’d be asking the testers to check their math and be sure they didn’t miss-type a decimal point!  A final thought on phosphorus, some additional testing was completed on 5/2/16.  It shows that input water just above and just below the north bridge at PA116 is delivering between 0.26 to 0.46 parts per million phosphorus.  Now go back to the table and 0.20 ppm levels at two of the three sites.  If we’re approaching the day when our ‘new’ aerobic bacterial digesters are munching the P a bit faster than it can replenish….wow!  In addition to this we will be placing filter bags at this site, as well as some other sites, which will help filter and neutralize phosphorus in the inflowing water.

The move to take action was mostly prompted by the vast eutrophication (over-nutrified, under-oxygenated) of our lake.  In plain English, we were down to just barely 10 feet of water with adequate oxygen to allow life.  Adequate oxygen for fish generally is a minimum of about 6 parts per million (ppm).  As of March, 2016 testing done in to help determine cause of the fish kill, there’s 12-14 ppm oxygen in the 15-20 foot depth range.  That is another great sign of improvement.

Unfortunately, I’m not a very good fisherman either but I’ll give you my best shot.  Anglers, you’re going to have to be a little bit savvier now.  The entire fish population of the lake is no longer confined to 5 foot depths in the inner reaches of the coves.  If my fish finder is reasonably on target, fish are now more widely dispersed throughout the lake.  An hour ago (3 pm, 5/26/16) I did a visual trolling…fish, some of very good size, were happily swimming at 20-25 ft. and a few showed up at 36 at the south end.  Still some near-surface clusters, but lots of open water now, so more skill may be needed and more fish stories will be offered.

I predicted last fall that the lake would remain colder now.  As of 5/26 I got temperature readings of 67-71 in coves and mid-lake.  Considering the wet and cold April, and the wet and chilly May, looks like we may have a shot at reasonably comfortable temps as well.  So, here are my predictions for the 2016 season:

2016 season

algae blooms: YES – these will continue since the water quality will now favor some (regular green algae) BUT, I’d guess now that the frequency will be down.

Blue-green algae (these are the toxic kind!): NO – with a decreasing phosphorus supply, this one won’t have the advantage anymore.

Water clarity: Have you looked lately? Great.

Dissolved oxygen: I’d predict a mid-summer decline.  Warm water degasses more quickly.  But overall it will be higher than the past few years and in Fall will increase even further.
Consider this less than one year into the project, it looks like Lake Savers is well on its way to meeting target goals (more likely exceeding them).  I for one am delighted.  Another year or two and I will be prepared to breathe a sigh of relief and state with conviction that we have saved our lake!

J. Doerr

Comment?  Why not drop a note to Matt at verdirame@yahoo.com or to our community manager, Mike, at mhanson@lakeheritage.org

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