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Results of VLAP Sampling from August 19, 2013


Total Phosphorus

Location
(Depth in Meters)

μg/L
Deep Spot (2) 5.78
Deep Spot (7) 14.3
Deep Spot (13) 32.4
Inlet 7.99
Outlet 7.05




 "Definition: Phosphorus is the most important water quality parameter measured in our lakes. It is the nutrient that limits the algae's ability to grow and reproduce. Phosphorus sources around a lake typically include septic systems, animal waste, lawn fertilizer, erosion from road and construction erosion, and natural wetlands." *

New Hampshire's Median Value = 12μg/L 

Total Phosphorus Ranges for 
New Hampshire Lakes and Ponds 
Total Phosphorus
(μg/L)

Category
1-10 Low (Good)
11-20 Average
21-40 High
>40 Excessive

μg/L = micrograms per liter

*Source: DES VLAP Chemical Parameter Explanations



Oxygen, Temperature, and Percent
Saturation Readings

Depth
(meters)
Temperature
(0C / 
0F)
Dissolved Oxygen
(mg/L)

Percent
Saturation
1 23.7 /  7.72 2
2 23.5 /  7.55 1
3 23.1 /  7.75 1
4 22.2 /  7.39 2
5 19.0 /  7.62 4
6 14.9 /  10.37 29
7 11.4 /  6.34 57
8 6.0 /  3.34 100
9 7.3 /  0.53 81
10 6.5 /  0.31 84
11 6.3 /  0.18 89
12 6.4 /  0.12 87
13 6.8 /  0.26 89

"Definition: Dissolved oxygen or 'DO' refers to the volume of oxygen contained within the water. Much of the DO in lakes comes from the atmosphere, inflowing streams and photosynthesis. Fish and other aquatic life depend on DO to survive. Seasonal changes can affect DO concentrations throughout the year. Warmer temperatures during the summer speed up the rates of photosynthesis and decomposition. When plants and algae die and decompose, oxygen is consumed. This decreases the amount of oxygen, especially in the uncirculated hypolimnion (lower) water layer. In the winter, under ice cover, the DO content can also deplete due to lack of circulation from the atmosphere.

DO levels above 5.0mg/L are considered sufficient for most aquatic life, although some cold water fish species require higher DO levels" *












mg/L = milligrams per liter

*Source: DES VLAP Chemical Parameter Explanations 


pH Readings

Location
(Depth in Meters)

pH

Deep Spot (2) 6.77
Deep Spot (7) 6.28
Deep Spot (13) 6.22
Inlet 6.71
Outlet 6.88


"Definition: pH is measured on a logarithmic scale of 0 to 14. Lake pH is important to the survival and reproduction of fish and other aquatic life. A pH below 5.5 severely limits the growth and reproduction of fish." *

pH Category

<5 Acidified
5.0-5.4 Critical
5.5-6.4 Endangered
6.5-8.0 Satisfactory

*Source: DES VLAP Chemical Parameter Explanations  



Acid Neutralization Capacity

Location
(Depth in Meters)

mg/L as CaCO3
 
Deep Spot (2) 6.4


"Definition: Buffering capacity or Acid Neutralizing Capacity (ANC) describes the ability of a solution to resist changes in pH by neutralizing the acidic input to the lake. Historically, the waters in NH have had low ANC because of the prevalence of granite bedrock. The relatively low ANC means that NH surface waters are vulnerable to the effects of acid precipitation." *

ANC
mg/l as CaCO3

Category

<0 Acidified
0-2 Extremely Vulnerable
2.1-10 Moderately Vulnerable
10.1-25 Low Vulnerability
>25 Not Vulnerable

mg/L = milligrams per liter 

*Source: DES VLAP Chemical Parameter Explanations  



Turbidity

Location
(Depth in Meters

NTUs
Deep Spot (2) 0.90
Deep Spot (7) 1.07
Deep Spot (13) 5.81
Inlet 0.94
Outlet 0.75


"Definition: Turbidity in the water is caused by suspended matter (such as clay, silt, and algae) that cause light to be scattered and absorbed, not transmitted in straight lines through the water. High turbidity readings are often found in water adjacent to construction sites. Also, improper sampling techniques (such as hitting the bottom sediments or sampling streams with little flow) may also cause high turbidity readings. The Class B standard for a water quality violation is 10 NTUs over the lake background level." *

 
Statistical Summary of Turbidity Values for NH Lakes and Ponds

Turbidity
NTUs

Category
<0.1 Minimum
22.0 Maximum
1.0 Median

NTUs = Nephelometric turbidity measurement

*Source: DES VLAP Chemical Parameter Explanations 
 



Conductivity

Location
(Depth in Meters)

μMhos/cm
Deep Spot (2) 81.5
Deep Spot (7) 84.6
Deep Spot (13) 107.7
Inlet 79.3
Outlet 81.8


"Definition: Conductivity is the numerical expression of the ability of water to carry an electrical current. It is determined by the number of ionic particles present. The soft waters of NH have traditionally had low conductivity values. High conductivity may indicate pollution from such sources as road salting, septic systems, wastewater treatment plants, or urban/agricultural runoff." *

"Note: Specific categories of good and bad levels can not be constructed for conductivity, because variations in watershed geology can result in natural fluctuations in conductivity. However, values in NH lakes exceeding 100 uMhos/cm generally indicate human disturbance."

μMhos/cm = micromhos per centimeter 

*Source: DES VLAP Chemical Parameter Explanations  



Chloride

Location
(Depth in Meters)

mg/L

Deep Spot (2) 14
Inlet 14
Outlet 15


"Definition: The chloride ion (Cl-) is found naturally in some surface waters and groundwaters and in high concentrations in seawater. Research has shown that elevated chloride levels can be toxic to freshwater aquatic life. in order to protect freshwater aquatic life in NH, the state has adopted acute and chronic chloride criteria of 860 and 230 mg/L respectively. The chloride content in NH lakes is naturally low, generally less than 2 mg/L in surface waters located in remote areas away from habitation. Higher values are generally associated with salted highways and, to a lesser extent, with septic inputs." *

mg/L = milligrams per liter 

*Source: DES VLAP Chemical Parameter Explanations  
 


Chlorophyll-A

Location
(Depth in Meters)
mg/m3

Deep Spot (7)
6.4


"Definition: VLAP uses the measure of chlorophyll-a, a pigment found in plants, as an indicator of the alga abundance. Because algae is a plant and contains chlorophyll-a, the concentration of chlorophyll-a found in the water gives us an estimation of the concentration of algae." *

Chlorophyll-a
mg/m3

Category
0-5 Good
5.1-15 More than desirable
>15 Nuisance amounts

mg/m3 = milligrams per meter cubed

*Source: DES VLAP Chemical Parameter Explanations  



Water Clarity
(Secchi-Disk Transparency)

Location

Secchi
(Meters)
Deep Spot 3.5 (NVS)


"Definition: The Secchi-Disk is a 20cm disk with alternating black and white quadrants used to measure water clarity (how far a person can see into the water). Transparency, a measure of water clarity, is affected by the amount of algae, color, and particulate matter with in the lake." *

 Water Clarity
(meters)

Category 
<2 Poor
2-4.5 Good
>4.5 Exceptional

NVS = Non-viewscope reading 
VS = Viewscope reading