Data period: through 2018

Town County Delorme Map # True Basin Flushing Rate Elevation
HERMON PENOBSCOT 22 1 31.09 flushes/yr 121 ft
Maximum Depth Average Depth Surface Area Lake Volume Drainage Area
5 m
(16 ft) 		3 m
(10 ft) 		179 ha
(442 ac) 		5,142,389 m3
(4,169 ac-ft) 		243 km2
(94 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
1980 48 0.80 1.7 2.4 6
1981 28 67 25 1.50 1.9 2.6 6 3.4 8.8 24.1
1984 27 35 1.80 2.5 2.8 6 19.1 19.1 19.1
1985 30 75 36 1.00 2.0 2.8 6
1986 1.40 1.8 2.5 6
1987 2.20 2.6 3.7 6
1988 2.20 2.6 3.1 6
1989 1.70 2.1 2.4 6
1990 2.00 2.4 2.7 6
1991 24 66 6.8 39 1.80 2.3 3.0 6 15.1 15.1 15.1
1992 2.70 3.0 3.4 2
1998 30 99 33 30 1.20 2.0 2.6 6 26.0 26.0 26.0
1999 1.10 1.8 3.0 5
2000 22 81 23 2.05 2.6 3.5 7 4.5 6.4 8.4
2001 1.50 2.2 3.1 6
2002 1.45 2.1 3.0 6
2003 50 34 112 7 37 0.88 1.7 2.6 6 60.0 60.0 60.0
2004 61 30 105 30 34 31 1.30 2.1 2.8 11 10.1 15.8 21.8
2005 29 18 0.60 1.8 2.9 10 20.0 20.0 20.0
2006 72 21 85 7.4 31 32 1.70 2.3 3.0 8 16.0 16.0 16.0
2007 1.05 2.2 3.4 6
2008 1.40 2.1 3.1 6
2009 41 48 1.70 2.2 3.1 7 28.0 28.0 28.0
2010 33 1.35 2.2 3.6 6 34.0 34.0 34.0
2011 1.92 2.7 3.4 6
2012 1.80 2.4 3.0 6
2013 2.05 2.6 3.4 6
2014 58 34 102 7.7 40 1.75 2.9 3.6 4 18.0 18.0 18.0
2015 1.67 2.5 3.9 6
2016 2.15 3.1 4.0 6
2017 0.80 1.8 2.8 6
2018 25 30 110 7.7 25 2.50 2.8 3.4 8 7.0 7.0 7.0

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
53 28 90 7.2 32 34 36 18 0.6 2.3 4 6.2 3.4 21 60

Temperature and Dissolved Oxygen Profiles

Late summer only; limited to eight most recent profiles

Units: Temperature (TEMP) = °C; Dissolved Oxygen (DO) = mg/L
2000-08-25
2003-08-19
2004-08-17
2006-08-09
2009-08-24
2010-09-02
2014-08-12
2018-09-06
Depth (m) TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO
0 22 8.7 25 9.1 23 8.9 25 7.5 25 8.0 25 9.7 25 10.0 25 8.8
1 22 8.8 25 9.1 22 9.0 25 7.4 25 8.0 25 9.5 24 10.2 25 8.8
2 22 8.8 25 8.9 22 7.9 24 6.3 25 7.9 25 9.1 23 7.6 25 8.7
3 22 8.8 24 5.8 21 3.4 23 6.1 24 0.6 23 7.1 22 5.4 25 8.6
4 22 8.7 22 0.3 21 2.7 23 1.6 19 0.5 22 3.8 21 0.1 24 6.8
5 20 0.2 20 0.9 19 0.2 18 0.5 24 4.7

Most recent temperature and dissolved oxygen profile plots

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