Pattison Lake is located six miles southeast of Olympia. It consists of two basins separated by a narrow channel. The north basin covers 75 acres and the south basin covers 190 acres. The north lake is fed by Hicks Lake, drains through south Pattison Lake to Long Lake, which ultimately drains to Henderson Inlet via Himes/Woodland Creek. Pattison Lake is also listed in references as Patterson Lake.

Size (acres)                          81
Maximum Depth (feet)                  22
Mean Depth (feet)                     14
Lake Volume (acre-feet)             1134
Drainage Area (square miles)        2.90
Altitude (feet)                      154
Shoreline Length (miles)             1.7

Contour Map

Source of morphometric data: Water Supply Bulletins 42, 43, and 57.

VOLUNTEER-COLLECTED SECCHI DATA ________________________________________________________________________________________________________________________ Date Temperature Water %Cloud Recent Secchi Lake (Y/M/D) (C) (F) pH Color Cover Rain Wind (ft) Ht(in) Abbrev. Comments ________________________________________________________________________________________________________________________ STATION 1 97/05/17 20.0 68.0 Dark Brn 75 Mod Calm 3.8 8.0 97/05/20 20.6 69.1 Dark Brn 0 None Light 3.0 8.0 A GREAT DEAL OF ALGAE THROUGHOUT THE WATER. 97/06/10 21.1 70.0 Dark Brn 10 None Light 3.8 8.5 BLUE-GREEN ALGAE 97/06/25 20.6 69.0 Lt Brown 25 Trace Breezy 4.0 0.0 97/07/11 21.1 70.0 Dark Brn 50 Trace Calm 5.0 0.0 97/08/04 26.7 80.1 Dark Brn 10 None Light 6.5 86.4 97/08/28 19.4 66.9 Dark Brn 100 Mod Light 9.0 68.0 WITH CHRIS DOE. 97/09/21 17.8 64.0 Lt Brown 0 None Light 6.8 82.0 WATER CLARITY HAS INCREASED. ________________________________________________________________________________________________________________________
LABORATORY RESULTS ________________________________________________________________________________________________________________________ Total Total Fecal Col. Bacteria Turb- Suspended Solids Phosphorus Nitrogen Chlorophyll (colonies/100 mL) idity Total Non-Volatile Color Date Strata (ug/L) (mg/L) (ug/L) Site 1 Site 2 (NTU) (mg/L) (mg/L) (Pt-Co) ________________________________________________________________________________________________________________________ There are no LWQA Program chemistry data for this lake in 1997. ________________________________________________________________________________________________________________________
SUMMARY OF VOLUNTEER SURVEY There was no survey response for 1997. FIELD OBSERVATIONS OF ECOLOGY STAFF There were no field observations recorded for PATTISON (NORTH ARM) (THURSTON) in 1997
TROPHIC STATUS Estimated Trophic State: Eutrophic Mean Trophic State Index (Secchi): 52 (Eutrophic) Mean Trophic State Index (Total Phosphorus): 0 (Not assessed) Mean Trophic State Index (Chlorophyll a): 0 (Not assessed)
SUMMARY AND EXPLANATION OF TROPHIC STATE ASSESSMENT Pattison Lake is assessed as eutrophic based on TSI values and the severly depleted summertime DO concentration in the hypolimnion. Additionally, Pattison Lake has many macrophytes that line the nearshore sediment. Information regarding TP and Chlorophyll TSI and information on the hypolimnetic DO concentration was provided by Thurston County Environmental Health.
Data collected and provided by Washington Department of Ecology's Lake Monitoring Program (Maggie Bell-McKinnon, phone 360- 407-6124).

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