2010 Report - Publicly Presented on July 23, 2011

2010 was the 20th 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 2010 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. The NHDES report on the quality of water in the lake for 2010 indicates the following:

1. The average amount of algae in the lake in 2010 was less than in the prior 2 years and virtually identical to that measured in 2007, which itself was the lowest seen since 1999, as indicated by the chlorophyll-a concentration. 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 amount of algae is only 71% of the average for New Hampshire lakes. 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 2.4 meters (7.9 feet), about 6 inches better than the previous year. As always, this 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 2010 were slightly more than in the previous 7 years (2003-2009), while still being slightly less than the 2 years prior to that (2001-2002). 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).

In the lower water layer, the phosphorus levels were slightly less than in the previous year and were approximately equal to the average of the previous 5 years (2005-2009). 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, with its 2010 level a bit higher than in the previous 2 years. The phosphorus concentration at the Island Inlet on Bonnyman Road was the highest since 2001. I suspect that culvert, bank, and road construction activity surrounding the Island Inlet sampling site in 2009 and 2010 is the main reason for the increase. 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. Province Lake experienced in September 2010 its first reported bloom of cyanobacteria (also known as blue-green algae). It was reported near the dam on 9/1, then sampled along Bonnyman Road on 9/2. The following report was sent to me in an email from Teresa Ptak of NH DES:

"Province Lake Effingham had a lake warning issued from 09/03/2010 to 09/15/2010. The initial sample analyzed on 09/02/2010 contained ~240,000 cells/mL of Anabaena circinalis. This sample was screened for microcystins and nodularins (toxin types) using the Microcystins Strip Test ... on December 30, 2010 and yielded 0 parts per billion (ppb) of toxin. As demonstrated by this result, not all cyanobacteria produce toxins, even at high cell concentrations. NH does not have a state standard for toxin concentration. We follow the guidelines put forward by the World Health Organization which recommends up to 1 ppb in drinking water and 20 ppb in recreational water as the action levels.

"New Hampshire only has a cyanobacteria state standard for designated public beaches. Our program will post advisories at beaches when a sample consists of more than 50% of a cyanobacteria cell type. The lake "warnings" were a new precautionary measure the program started in 2008. Warnings are a result of informing the shoreline owners and the public who may recreate in the waters, not necessarily at the beach area, of the presence and potential dangers of cyanobacteria. The concentration of cells present is also another way to assess the public health risk. NH does not currently have an action level for cyanobacteria cell concentration in lakes however, we do use the current standard for recreational contact set at 70,000 cells/mL by Massachusetts as a guideline. We assess percentage, cell concentration and the area of the bloom when issuing a lake warning.

"Cyanobacteria (formerly called blue-green algae) are present in all lakes around the world and it is true that some species of cyanobacteria produce toxins, however; it is only when a visible bloom of cyanobacteria is present that we recommend avoiding contact. Research indicates that cyanobacteria increase as nutrients to the waterbody increase. Fertilized lawns, failing septic systems, and urban runoff are all contributors. Cyanobacteria species may spend a portion of their life cycle on the lake bottom during the winter months. Increased water temperature and light in the spring promote the upward movement of cyanobacteria through the water column toward the surface where blooms or scums are formed when conditions are optimal."

I have been educating you about cyanobacteria for several years, and am pleased that it seems to have paid off. I received notification of the Lake Warning just in time to post it to the lake's Facebook page the same day.

As a reminder, 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 September 2010. 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 especially, keep your children and pets out of the water. 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 Lake Warning 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 of 6.0 to 7.0 is ideal for fish. The state average is 6.6. The pH in the upper water layer of Province Lake in 2010 was an average of 6.9, the closest we have been to the neutral pH of 7.0 since 2001. Even the lower water layer pH rose to 6.8 in 2010, the highest it has been since measurements of the lower water layer pH were started in 2000. This may indicate that we are not having an acid rain problem here. The pH at the Rt. 153 inlet was 5.8, more acidic than 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. Acid neutralizing capacity (ANC) describes the ability of water to buffer against acidic inputs, like acid rain. This is also known as a lake's alkalinity. It is always measured, but I have not included it in the summary before. I mention it now, because in 2010 our average ANC was the highest measured in our 20 years of data. I don't know why it has increased, but that increase may account for the increase in lake pH. A higher ANC is desirable, because it makes the lake less vulnerable to acidification. The NH median ANC is 4.9 mg/L as calcium carbonate (CaCO3) and our average ANC in 2010 was 5.7 mg/L as CaCO3.

8. E. coli bacteria testing of a sample taken from the lower section of the campground brook on August 26, 2010, showed 750 counts per 100 milliliters (cts/100mL), which exceeds the State standard of 406 cts/100mL for recreational surface waters. Sara Steiner at VLAP speculated that the high count could have been natural, due to high temperatures and low stream flow, with stagnating conditions. We have done additional sampling in the brook this year (2011) to explore whether there is a problem. On June 16, 2011, the same location had 360 cts/100mL, below the state standard, but upstream at the culvert where Remick Road crosses the brook, the result was 1,060 cts/100mL. On July 8, 2011, those respective locations had 86 and "less than 10" cts/100mL. At a third location 200 feet upstream of the road, 10 cts/100mL was measured. This likely means that the source of the high readings is wildlife, not the campground. Since the brook has minimal outflow, it is likely that any E. coli counts here will have minimal effect on the lake water quality, however, these results do lead me to recommend caution about entering the brook's waters. Monitoring is continuing.

9. The dissolved oxygen concentration measured in 2010 showed a high degree of saturation at all depths sampled in the deep part of the lake. A 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.

Loons and Lead

A study published in 2009 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, lead fishing sinkers have been outlawed so, if you still own any lead fishing gear, please stop using it immediately. The Loon Preservation Committee visitor center is one of the many locations where old lead gear can be disposed of safely.

Asian Longhorned Beetle

The Asian Longhorned Beetle (ALB) is an invasive tree-killing beetle 0.75 - 1.25 inches long, with long antennae and a black body covered with white spots. It is a severe threat to any forest to which it is introduced. The ALB reporting hotline number is 866-702-9938. Please always use local firewood, to keep from spreading this beetle and other wood pests (such as Emerald Ash Borer) around. It is illegal to move firewood across most state lines in the Northeast now, and Province Lake is perched on a state line, so be careful to keep out of trouble.

Other Web Site Listings

Last year's summary report is posted HERE. That is the 2009 report, publicly presented on July 17, 2010.

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 information, photos, and events. As of 8/25/2011, the Facebook page had 37 members.

Return to the Province Lake Water Quality Home Page.

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.

Province Lake Statistics from Appendix F of the State Report, Which has Statistics for All VLAP Lakes

Maximum depth: 4.9 meters = 16.1 feet

Average depth: 2.8 meters = 9.2 feet

Volume: 11,268,500 cubic meters = 2.98 billion gallons

Lake area: 410.37 hectares = 1,014 acres = 1.58 square miles

Watershed area (which includes the lake surface area): 1,890.7 hectares = 4,672 acres = 7.30 square miles

Flush rate: 1.0 time per year (annual outflow = lake volume)

Note that Province Lake is a member of Group 3 in Appendix F. This group includes the largest of the shallowest lakes in NH.

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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