2009 was the nineteenth consecutive year of water quality monitoring conducted at Province Lake as part of the New Hampshire Volunteer Lake Assessment Program (VLAP). We sampled four times last season. The test results for 2009 on water samples collected by Steve & Mary Craig were reviewed by the New Hampshire Department of Environmental Services (NHDES). State reports for a number of years are available by clicking this web site.
Many of the terms in this report include hyperlinks to interesting related web sites. By clicking on most of the underlined terms, you can access additional information. If the same word is hyperlinked more than once, the different occurrences lead to different web sites.
For those lakes with at least 10 consecutive years of data, the State does a special report every 2 years. This was our "Biennial Report" year, so a statistical regression analysis was conducted to determine objectively if lake quality has changed over time. This is a major payoff for having had a continuous and consistent sampling program. The overall summary is that no statistically analyzed parameters have changed significantly since 1991. The NHDES report on the quality of water in the lake for 2009 indicates the following:
1. The average amount of algae in the lake was only slightly more than the low levels of the previous 3 years, as indicated by the chlorophyll-a concentrations. The 2009 mean concentration falls exactly on the 19-year trend line, so the slight short-term increase is of no concern. We have never returned to the high levels observed during the weed removal activities of 1996 and 1997, and their lingering effects in 1998. The State's statistical analysis shows that the amount of algae has not significantly changed over all the years since monitoring began in 1991. Our amount of algae is only about 85% of the amount that New Hampshire lakes have, on average. This low level is good because dying algae forms the brown floating bottom masses that come to your shore when the wind blows hard in July and August. The algae masses settle loosely on the bottom when the lake is still and cloud the water when wind or boat wakes stir things up.
2. Water transparency (a measure of how deep you can see into the water) was an average of 2.2 meters (7.2 feet). This lies within 4 inches of the average of the annual averages for 4 of the last 5 sampling seasons, indicating that transparency is quite stable. (2007 was especially clear, 20 inches better than the average.) The State's statistical analysis shows that the transparency has not significantly changed since monitoring began in 1991. As always, Province Lake's transparency was less than the statewide median of 3.2 meters (10.5 feet), but is not unreasonable considering that we have a shallow lake, so sediments are easily stirred up. The shallowness means that it is important to educate lake users on the importance of operating jet skis and boats at slow speeds in shallow areas to minimize disturbance to sediments and vegetation. Churning up the bottom sediments releases phosphorus, which promotes algae growth, increases turbidity (scattering of light by suspended particles), and decreases clarity.
The deepest part of the lake is only 16 to 17 feet deep, as shown on the bathymetric chart.
3. Phosphorus is a nutrient required for plant and algae growth and is typically the nutrient whose availability most limits plant and algae growth in NH lakes. The average phosphorus levels in the upper water layer in 2009 were slightly more than in the previous 5 years (2004-2008), while still being slightly less than the 3 years prior to that (2001-2003). At this time, the small increase appears to be simply a matter of natural variation, and not a cause for concern. As is typical for Province Lake, this level is slightly higher than in 50% of the lakes in NH (the median). The State's statistical analysis shows that the phosphorus concentration has not significantly changed since monitoring began in 1991.
In the lower water layer, the phosphorus levels were slightly more than in the previous 5 years (2004-2008), while still being slightly less than 2 prior years (2001-2002). Our lower level phosphorus was slightly above the NH median, but was actually below the median for lakes in NH that are similar to Province Lake. This is a good thing. Again, powered watercraft disturbance of bottom sediments is probably an important source of phosphorus for our lake. Too much phosphorus may increase the growth of plants and algae in the lake.
The phosphorus concentration at the Rt. 153 Inlet continues to be elevated, although its 2009 level was the 4th year of a downward trend and was the 4th lowest in 19 years. The phosphorus concentration at the Island Inlet on Bonnyman Road (32.3 milligrams per liter (mg/L)) was greater than the prior 2 years, though still 13% less than the long-term average of 37.1 mg/L. The State speculates that the recent increase may be due to beaver activity upstream, however, I noted culvert construction activity in 2009 that could also be a contributor. Phosphorus clings to sediments, so soil erosion and sediment disturbance from road construction can increase phosphorus concentrations. Both inlet locations have a history of elevated and fluctuating total phosphorus concentration.
4. We have never sampled Province Lake for nitrogen as part of the monitoring program. However, a 1987 DES Lake Assessment Program survey determined that plant and algae growth in Province Lake is actually limited by the amount of nitrogen, rather than by phosphorus. Therefore, it is important to be sure nitrogen-containing fertilizers are not used near the shoreline, or streams or ditches feeding the lake, and to be sure septic systems are operating properly.
5. Cyanobacteria (also known as blue-green algae) have occasionally been detected among plankton samples in Province Lake in the past. If present in large amounts, cyanobacteria can be toxic to animals and humans. Large concentrations would be caused by a bloom, which would be seen as the formation of a green, blue, or pink surface scum in a section of the lake. Bear in mind that this is different from the tan or yellowish foam seen sometimes after strong winds. It will likely look different than what you have seen before. While the current report does not mention cyanobacteria in our lake, please be aware that these bacteria are always here. While recreational exposure to cyanobacteria toxins is a major concern of NHDES, there have been no documented cases of cyanotoxin-related illnesses in New Hampshire.
If you think you are seeing a bloom, stay out of the water and call the NHDES Cyanobacteria Hotline at (603) 419-9229 to describe what you see. If suspicious, NHDES will sample and analyze the suspected bloom, then post a No Swimming advisory if there is any danger. They will monitor the situation and remove the postings when all is clear.
The best ways to avoid having cyanobacteria blooms are by eliminating fertilizer use on lawns, keeping the lake shore natural, protecting against shoreline erosion, and properly maintaining septic systems.
6. A pH between 6.0 to 7.0 is ideal for fish. Ours in 2009 was an average of 6.6, equal to the average for the state. The pH at the Rt. 153 inlet was 5.9, close to its long-term average of 6.0. Since it drains a large wetland, it has a high concentration of tannic, humic, and fulvic acids, which give it the color of tea and reduce its pH. No problem is indicated.
7. The dissolved oxygen concentration was more than adequate at the bottom in the deep part of the lake, at about 64% of saturation The average concentration was about 79% of saturation in the top 3 meters (10 feet) of the water. An average high oxygen level is a sign of the lake's overall good health. I encourage powered watercraft to operate far from the shore to mix the deep waters and boost the oxygen concentration, while minimizing their operation in the shallows, which can cause problems with excess phosphorus.
8. In June 2009, one sample was taken at the Boat Launch for E. coli bacteria testing. The result was "10 counts or less" per 100 milliliters (mL), which is much less than the State standard of 406 counts per 100 mL for recreational surface waters. None of our samples have ever been over 1/4 of the State standard.
9. In June 2009, 2 fish were submitted to NHDES for mercury analysis. A letter from NHDES indicated that both of the fish would have been safe to consume. This is good news for our loons, and if you want to eat a fish occasionally, you can. However, only 2 fish out of a lake is not a sufficient sample size to prove all fish are safe for human consumption, so it is best to be cautious. Also, continuing to do catch-and-release leaves more food for the loons and means you will have better luck getting some action when fishing.
A study published last year 1 addressed the ingestion of lead objects by loons. Most birds swallow small stones to help them digest food. Many fishing sinkers fall into the size range that loons prefer. Being fish-eaters, loons have a lower stomach pH than waterfowl that eat vegetation, such as geese and most ducks. The lower pH more effectively dissolves the lead, which then kills the bird. Poisoning from ingestion of lead objects is the #1 cause of loon deaths in fresh water. Therefore, if you still own any lead fishing gear, please stop using it immediately. [See the 2008 report for more details.]
The Asian Longhorned Beetle is a tree-killing insect 0.75 - 1.25 inches long, with long antennae and a black body covered with white spots. It is an invasive beetle that was first detected in New England in August 2008 in Worcester, Massachusetts. Since then, well over 25,000 trees have been removed and destroyed in a quarantine area of >74 square miles in that region. It was also recently discovered across the street from the Arnold Arboretum in Boston.
The Asian Longhorned Beetle affects you in two ways:
1. Please always use local firewood, to keep from spreading this beetle and other wood pests around. There are large fines for knowingly removing wood from the Worcester quarantine area. This April, Maine banned bringing firewood from other states into Maine, unless it is kiln-dried. Technically, this means you cannot take firewood across the lake from New Hampshire to Maine, so be careful not to get into trouble.
2. Watch for the beetle (July - October, most active in August), and more importantly, for signs of it.
-- 3/8 to 1/2 inch diameter round exit holes, which may ooze sap
-- Sawdust in tree crotches
-- Tree leaves with only the midribs eaten out
-- Trees dying from the top down (since the beetles and their larvae start eating at the top)
-- Firewood with 3/8 to 1/2 inch diameter round tunnels through it, eaten out by the larvae
-- If you suspect you have found evidence of the beetle, call 866-702-9938 from anywhere in the northeast US to report your possible discovery. Your call will be relayed to the appropriate agency, based on the area code you call from.
-- NOTE that all Asian Longhorned Beetle infestations in the US so far have first been discovered by individuals with no professional training. If you think you may have found something, don't be shy. Tell the professionals and let them check it out. This beetle can appear anywhere infested wood may have been moved to, which makes areas in and around campgrounds especially vulnerable.
-- You can learn much more at the following web sites:
-- http://www.massnrc.org/pests/alb/
-- http://www.uvm.edu/albeetle/
-- http://www.dontmovefirewood.org/
[See the 2008 report for many more details.]
I have created a Facebook page called "Province Lake, New Hampshire & Maine", which is not part of any organization, but where people interested in the lake can share photos and information.
THANK YOU NOTE: I want to thank Steve Craig for taking the lead on the VLAP sampling activity since 2004. Each year the State report grades each sampling program and each year Province Lake receives Excellent ratings for sample collection and submittal. Thank you to Steve, and others who have helped out from time to time! We can always use more volunteers to help Steve with sampling, deliveries, or both, so please contact Steve or me, or any member of the PLA board if you are interested in helping out. You may also use the general PLA e-mail address, info@ProvinceLake.org. The PLA currently coordinates and provides financial support to the VLAP effort on Province Lake. You do not need to be a member of the PLA to volunteer, and have no obligation to join if you do volunteer, although new or returned members are always welcome.
Respectfully submitted,
Norm Dudziak, P.E., I.M.
FOOTNOTES:
1. Pokras, Mark; Kneeland, Michelle; Ludi, Anna; Golden, Ethan; Major, Andrew; Miconi, Rose; and Poppenga, Robert H. "Lead Objects Ingested by Common Loons in New England." Northeastern Naturalist 16(2):177-182, Humboldt Field Research Institute, Steuben, Maine, June 30, 2009.
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