Data period: through 2018

Town County Delorme Map # True Basin Flushing Rate Elevation
UNION KNOX 14 1 3.84 flushes/yr 109 ft
Maximum Depth Average Depth Surface Area Lake Volume Drainage Area
17 m
(57 ft) 		5 m
(17 ft) 		232 ha
(573 ac) 		11,983,210 m3
(9,715 ac-ft) 		33 km2
(13 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
1974 13.0 47 4.0 4.6 5.5 2
1975 8.5 4.9 5.2 5.5 2
1976 5.2 5.2 5.2 1
1980 4.0 5.8 6.6 4
1981 8.5 34 11 23 5.3 6.1 7.2 5 3.0 3.0 3.0
1982 10.0 58 11 15 4.5 5.2 5.8 5 1.0 3.2 5.9
1983 4.6 5.2 6.1 6
1984 5.0 5.3 5.6 5
1985 7.0 35 8 15 5.0 5.2 6.3 6
1986 8.0 40 11 20 4.1 4.6 5.4 3
1987 3.6 5.2 6.3 6
1989 3.7 4.5 5.5 5
1990 4.6 4.9 5.5 4
1991 11.0 39 7.0 8 4.3 5.4 5.8 6
1992 2.4 5.1 6.4 5
1993 8 2.0 5.8 8.0 6
1995 4.4 5.5 6.3 6
1997 7.0 45 7.0 8 19 4.5 5.1 5.8 5 3.8 3.8 3.8
1998 4.0 4.5 5.1 3
2000 4.2 4.5 5.0 4
2001 4.4 5.2 6.2 5
2002 20 10.0 55 8 19 4.4 5.1 5.7 5 6.0 6.0 6.0
2003 3.7 5.4 7.2 6
2004 5.1 5.2 5.3 3
2005 4.8 5.0 5.2 6
2006 4.6 5.0 5.3 5
2007 15 7.4 48 7.1 8 4.9 5.8 6.5 6 4.2 4.2 4.2
2008 25 7.9 53 6.9 7 5.4 5.8 6.0 4
2009 8 4.2 4.4 4.5 3
2010 11 5.6 6.3 6.9 4
2011 5.5 6.0 6.3 3
2012 4.1 5.2 6.0 3
2013 4.3 5.2 5.7 3
2015 8.0 54 6 16 6.5 6.5 6.5 1 3.0 3.0 3.0
2016 14 9.5 57 7.1 12 5.1 5.8 6.7 7 2.7 2.8 2.9
2017 4.8 5.5 6.0 4
2018 4.6 5.5 6.1 3

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
19 8.9 47 7 9 8.7 18 2 5.3 8 4.3 1 3.7 6

Temperature and Dissolved Oxygen Profiles

Late summer only; limited to eight most recent profiles

Units: Temperature (TEMP) = °C; Dissolved Oxygen (DO) = mg/L
1986-08-21
1991-09-06
1993-09-09
1997-08-18
2002-08-12
2007-08-15
2015-08-19
2016-08-24
Depth (m) TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO
0 23 8.4 21.1 9.9 21.8 8.3 23.0 8.3 25 8.0 23.1 8.1 27.6 8.0 24.3 8.0
1 22 8.4 21.1 9.7 21.8 8.3 23.0 8.2 25 7.9 23.1 8.1 27.1 8.1 24.1 8.0
2 22 8.3 21.0 9.8 21.8 8.2 23.0 8.2 24 7.7 23.1 8.1 26.4 8.2 24.0 8.0
3 22 8.3 21.0 9.8 21.8 8.2 23.0 7.8 24 7.6 23.1 8.1 25.2 8.1 23.9 8.0
4 22 8.2 20.8 9.8 21.8 8.1 23.0 7.8 23 6.7 23.0 8.1 24.2 8.0 23.9 8.0
5 22 8.0 20.8 9.6 21.8 8.2 22.8 7.8 23 5.5 22.6 7.7 22.8 6.0 23.9 8.0
6 20 3.6 20.5 9.2 21.5 6.9 20.8 3.1 18 1.3 18.7 3.1 21.1 3.1 23.7 7.3
7 19 1.7 20.0 7.8 19.8 3.3 15.8 0.3 16 1.5 14.8 1.4 17.7 1.3 19.3 2.0
8 15 1.4 15.5 0.8 14.9 1.6 13.2 0.2 14 2.0 11.8 2.4 13.3 2.8 16.8 2.1
9 14 1.3 12.2 1.5 11.1 2.5 12.0 0.2 13 2.6 10.2 3.3 10.5 4.7 13.5 3.0
10 10 1.6 10.2 1.7 8.8 2.9 11.0 0.2 11 2.0 8.5 3.7 8.5 5.1 11.1 3.1
11 9 1.6 9.0 1.7 8.0 2.3 10.1 0.2 11 1.2 7.7 3.4 7.7 4.6 10.1 2.8
12 8 1.3 8.2 0.7 7.6 1.8 9.9 0.2 10 0.3 7.1 3.0 7.2 3.1 9.5 2.8
13 8 1.0 8.0 0.5 7.1 0.8 9.8 0.2 10 0.2 6.9 2.3 7.0 2.1 9.2 1.5
14 8 0.9 7.9 0.3 9.2 0.1 10 0.1 6.9 2.0 6.9 1.2 8.6 0.9
15 8 0.8 7.8 0.3 9.2 0.1 6.8 1.9 6.9 0.5 8.5 0.8
16 8 0.7 7.6 0.3 6.9 0.1

Most recent temperature and dissolved oxygen profile plots

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