Data period: through 2018

Town County Delorme Map # True Basin Flushing Rate Elevation
HARTLAND SOMERSET 21 1 4.42 flushes/yr 245 ft
Maximum Depth Average Depth Surface Area Lake Volume Drainage Area
15 m
(50 ft)
4 m
(15 ft)
1,449 ha
(3,582 ac)
65,000,000 m3
(52,696 ac-ft)
514 km2
(198 mi2)

Secchi Disk Transparency Graphs

Graph Legend: Secchi symbols = average Secchi Disk Transparency Values; tick marks = maximum and minimum values for each year.

Water Chemistry and Trophic State Parameters

Table Legend:

Color: Color (SPU), Alk: Alkalinity (mg/l CaCO3), SpCon: Specific Conductivity (\(\mu\)S/cm), pH: pH (standard units)

TP = Total Phosphorus (\(\mu\)g/L) – EC: Epilimnion Core, SG: Surface Grab, BG: Bottom Grab, PG: Profile Grab

SDT = Secchi Disk Transparency (m) – Min: minimum value, Avg: average value, Max: maximum value, n: number of months with Secchi readings per year, b: number of times Secchi disk was observed touching the bottom of the lake per year

Chl = Chlorophyll-a (\(\mu\)g/L) – Min: minimum value, Avg: average value, Max: maximum value
Year Color Alk SpCon pH TP-EC TP-SG TP-BG TP-PG SDT-Min SDT-Avg SDT-Max SDT-n SDT-b Chl-Min Chl-Avg Chl-Max
1970 5.0 5.5 6.2 4
1971 2.7 4.5 5.4 6
1972 3.9 4.5 5.2 3
1979 3.6 4.0 4.2 3
1980 3.5 3.8 4.5 3
1989 10 4.5 4.5 4.5 1
1995 10.5 5.2 5.2 5.3 2
2000 11 6.9 9.5 22 3.8 5.1 5.9 5 4.2 4.5 4.8
2001 8.0 29 4.1 5.2 6.3 4 2.7 2.7 2.7
2002 14 6.7 8.5 12 3.9 4.8 5.4 6 2.2 3.1 4.0
2003 10 58 6.9 9.0 17 4.0 4.6 5.5 7 3.1 5.0 6.8
2004 15 6.7 12.0 20 4.2 5.3 6.5 3 2.3 4.1 5.9
2005 13 44 6.6 10.0 12 3.8 4.3 4.9 4 4.7 4.8 4.8
2006 14 7.2 11.5 16 4.4 5.0 5.6 5 2.6 4.0 5.4
2007 15 7.1 8.5 14 5.1 5.2 5.5 3 3.1 3.4 3.8
2008 7.0 18.0 16 4.0 4.7 5.4 2 2.7 4.4 6.2
2009 20 9.0 14 5.3 5.3 5.3 1 2.5 2.5 2.5
2010 7.5 43 5.9 6.1 6.3 2 3.1 4.0 4.9
2012 17 11.0 14 4.4 4.4 4.4 1 4.6 4.6 4.6
2013 5.3 5.3 5.3 1
2014 7.0 11 3.9 3.9 4.0 1 3.7 3.7 3.7
2015 49 6.0 18 5.8 5.8 5.8 1 4.0 4.0 4.0
2016 6.0 33 5.8 5.8 5.8 1 3.2 3.2 3.2
2017 57 7.4 7.0 38 6.0 6.0 6.0 1 2.6 2.6 2.6
2018 14 8.0 25 6.5 6.5 6.5 1 2.0 2.0 2.0

Lake Chemistry and Trophic Summary Data - Overall Summary Values:

Avg Color Avg Alk Avg SpCon pH Avg TP-EC Avg TP-SG Avg TP-BG Avg TP-PG SDT-Min SDT-Avg SDT-Max SDT-n Chl-Min Chl-Avg Chl-Max
14 52 6.9 9.3 21 10 2.7 5 6.5 2.8 2 3.7 6.8

Temperature and Dissolved Oxygen Profiles

Late summer only; limited to eight most recent profiles

Units: Temperature (TEMP) = °C; Dissolved Oxygen (DO) = mg/L
2009-08-14
2010-08-19
2012-08-06
2014-08-11
2015-08-18
2016-08-23
2017-09-14
2018-08-11
Depth (m) TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO
0 26 8.8 25 8.3 27 8.0 27 8.2 29 8.3 24 8.3 23 8.4 28 8.0
1 25 8.8 25 8.4 27 8.0 26 8.2 28 8.6 24 8.3 21 8.8 28 8.0
2 24 8.6 24 8.4 27 8.0 23 7.5 27 8.5 24 8.3 20 8.8 28 8.0
3 22 7.7 24 8.4 25 7.6 23 6.2 25 8.8 24 8.3 20 8.5 27 8.1
4 22 7.1 24 8.3 24 6.2 22 4.5 24 7.8 24 8.3 20 8.4 26 8.0
5 21 5.8 24 8.1 22 4.3 22 3.6 23 6.6 24 8.3 20 8.1 26 7.7
6 20 4.0 23 7.1 22 3.6 20 1.3 23 6.0 23 8.2 19 7.8 24 3.8
7 18 1.9 23 6.8 18 0.2 20 0.1 22 3.7 23 8.1 19 7.5 22 0.7
8 17 1.3 18 0.1 14 0.2 18 0.0 18 0.0 20 0.4 18 6.8 20 0.1
9 16 0.2 15 0.1 13 0.1 14 0.0 14 0.0 15 0.1 17 3.2 14 0.1
10 15 0.0 14 0.1 13 0.1 12 0.0 12 0.0 13 0.0 13 0.1 12 0.1
11 14 0.0 13 0.1 12 0.1 12 0.0 11 0.0 13 0.0 12 0.1 11 0.1
12 14 0.0 13 0.1 12 0.1 12 0.0 11 0.0 12 0.0 12 0.1 11 0.1

Most recent temperature and dissolved oxygen profile plots

Temperature (°C), Dissolved Oxygen (mg/L)