Data period: through 2017

Town County Delorme Map # True Basin Flushing Rate
WILLIMANTIC PISCATAQUIS 32 1 1.43 flushes/yr
Maximum Depth Average Depth Surface Area Lake Volume Drainage Area
47 m
(155 ft) 		13 m
(43 ft) 		2,658 ha
(6,568 ac) 		349,488,384 m3
(283,335 ac-ft) 		414 km2
(160 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
1981 3.2 5.2 7.0 5
1982 7.0 30 2 6 4.6 6.4 8.2 5 1.4 1.4 1.4
1983 3.9 6.0 7.6 5
1984 4.9 6.4 8.3 5
1985 7.0 30 4 3 6.6 6.6 6.6 1
1987 3 5.5 5.8 6.1 3
1988 4.9 5.9 7.8 4
1989 4.3 5.6 7.3 4
1990 4.3 5.8 8.2 4
1991 9.0 7.2 4 4.3 5.8 6.8 4
1992 4.0 6.7 8.5 3
1993 4.3 6.2 9.1 3
1994 4.3 5.5 7.1 4
1995 5.3 6.4 9.0 4
1996 4.4 5.3 6.4 5
1997 5.0 26 7.0 3 4.5 7.2 8.6 4 1.4 1.4 1.4
1998 5.5 5.9 6.2 3
1999 6.5 7.4 7.9 3
2000 8.0 8.4 8.8 1
2001 7.5 7.8 8.2 4
2002 31 16.0 28 1 7.8 8.1 8.5 4 2.7 2.7 2.7
2004 7.6 8.0 8.4 1
2012 6.7 6.7 6.7 1
2013 25 6.8 23 7.1 4 6.8 6.9 6.9 1 1.7 1.7 1.7
2016 7.3 8.3 9.2 2
2017 6 5.0 7.1 8.3 4

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
28 8.5 27 7.1 3 4.5 4.5 3.2 6.6 9.2 3.3 1.4 1.8 2.7

Most recent late summer temperature and dissolved oxygen profiles

Units: Temperature (TEMP) = °C; Dissolved Oxygen (DO) = mg/L
1997-08-08
1997-08-12
1997-08-24
1997-09-13
2000-08-01
2000-08-22
2002-08-14
2013-08-22
Depth (m) TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO TEMP DO
0 21.0 8.6 23.1 8.8 20.0 9.1 19.0 9.0 24 8.4 23 7.0 26.1 8.5 23.7 8.6
1 23.1 8.7 24 8.2 21 7.4 24.7 8.7 23.5 8.6
2 20.5 8.8 23.1 8.9 19.5 9.4 18.7 9.4 23 8.4 21 7.4 24.3 8.7 23.3 8.5
3 20.0 8.8 23.0 8.9 19.5 9.4 18.6 9.3 23 8.4 21 7.6 23.1 9.0 23.2 8.7
4 22.9 8.9 23 8.6 21 7.6 22.5 9.0 22.2 8.7
5 20.0 8.9 22.6 8.9 19.5 9.4 18.6 9.3 22 8.4 20 7.6 21.7 8.8 21.2 8.6
6 20.0 8.8 21.6 8.9 19.5 9.3 18.5 9.3 20 8.2 20 7.4 21.3 8.7 20.5 8.5
7 18.9 8.5 20 8.0 20 7.4 20.8 8.5 19.6 8.3
8 16.5 9.2 18.3 8.5 19.0 9.2 18.5 9.3 18 8.0 18 7.2 19.8 8.2 18.9 8.0
9 14.0 9.4 16.7 8.6 17.0 9.0 16.9 9.2 16 8.0 18 6.8 16.7 8.2 14.4 7.7
10 11.8 9.6 15 8.2 15 6.8 15.2 8.3 12.5 8.2
11 11.0 10.0 10.5 9.8 12.0 10.0 12.4 9.0 12 8.6 13 7.0 13.9 8.5 10.6 8.9
12 9.0 10.4 9.9 9.9 10.0 10.2 10.1 10.5 12 8.8 12 7.0 13.3 8.7 9.9 9.1
13 9.5 10.1 10 9.0 11 7.6 12.4 8.9 9.4 9.3
14 8.5 10.4 9.1 10.1 9.0 10.5 9.0 10.5 10 9.0 11 7.8 11.8 9.1 9.2 9.4
15 8.0 10.8 8.9 10.2 8.5 10.8 8.7 10.5 9 9.5 10 8.0 11.3 9.2 8.3 9.8
16 8.4 10.3
17 7.5 10.8 8.2 10.4 8.0 10.8 7.5 10.8 10.4 9.5 7.5 10.1
18 7.0 10.8 8.0 10.4 7.5 10.8 7.5 10.8
19 9.5 9.8 6.3 10.6
20 7.0 10.8 7.7 10.6 7.0 11.0 6.8 11.0
21 6.5 10.9 7.0 11.0 6.8 11.0 9.0 9.9 5.6 11.0
22 7.5 10.6
23 6.0 11.0 7.0 11.0 6.2 11.3 8.5 10.1 5.4 11.2
24 6.0 11.2 7.3 10.7 6.5 11.2 6.0 11.3
25 8.3 10.2 5.3 11.2
26 6.0 11.2 7.1 10.7 6.5 11.3 6.0 11.3
27 6.0 11.2 6.1 11.5 6.0 11.5
28 7.1 10.6
29 5.8 11.2 6.0 11.5
30 7.0 10.5 7.9 10.1 4.9 11.3
31
32
33
34
35 7.0 10.7 7.6 10.1 4.7 11.3
36
37
38
39
40 7.0 10.3 7.5 9.9 4.6 11.2
41
42
43
44
45 7.0 10.2 7.5 9.7 4.5 11.1

Recent temperature and dissolved oxygen profile plots

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