Size (acres)                          88
Maximum Depth (feet)                  25
Mean Depth (feet)                     12
Lake Volume (acre-feet)             1056
Drainage Area (square miles)        1.83
Altitude (feet)                      516
Shoreline Length (miles)             1.9

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 ________________________________________________________________________________________________________________________ There are no Secchi data available for 1995. ________________________________________________________________________________________________________________________
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) ________________________________________________________________________________________________________________________ STATION 1 95/05/23 E 18 0.16 6.0 95/08/14 E 30 0.17 7.0 95/08/14 H 35 0.21 ________________________________________________________________________________________________________________________ E=epilimnion composite, H=hypolimnion composite. Remarks codes: U = Below detection limits; J = Estimate.
SUMMARY OF VOLUNTEER SURVEY There was no survey response for 1995. FIELD OBSERVATIONS OF ECOLOGY STAFF There was a cluster of approximately 10 purple loosestrife plants (Lythrum salicaria) at the public boat launch.
TROPHIC STATUS Estimated Trophic State: Mesotrophic Mean Trophic State Index (Secchi): 39N* (Oligo-mesotrophic) Mean Trophic State Index (Total Phosphorus): 53 (Eutrophic) Mean Trophic State Index (Chlorophyll a): 49 (Meso-eutrophic) *The calculated TSI is an estimate. The Secchi disk hit bottom (B), entered the weeds (W), or there were too few valid readings (N), or the calculation was based on qualified data (J), or TSIP was based on spring data (S).
SUMMARY AND EXPLANATION OF TROPHIC STATE ASSESSMENT Mission Lake exhibits many characteristics of an eutrophic or meso-eutrophic lake, however, water clarity is quite good. The relatively good water clarity may be due to the small sample size for the Secchi data or could be due to a more dominant blue-green algal population which tends to increase water clarity in situations where the blue-greens aren't visually abundant. All criteria considered, Mission Lake is classified as mesotrophic.
COMMENTS FROM 98/06/18 AQUATIC PLANT SURVEY Cloudy, light breeze. Still early in the season, plants ring shore. Utricularia inflata blooming, mostly growing in outlet cove. Most of shore with homes. Osprey, bullfrogs, ducks, goose family. Most of shoreline with moderate to heavy plant growth, few areas at east end with no plants. Maximum depth of plant growth: 5.0M.
AQUATIC PLANT LIST (This list may be from multiple years and sources.) Brasenia schreberi (watershield) Ceratophyllum demersum (Coontail; hornwort) Chara sp. (muskwort) Cyperus sp. Elodea canadensis (common elodea) Elodea nuttallii (Nuttall's waterweed) Elodea sp. (waterweed) Iris pseudacorus (yellow flag) Juncus sp. (rush) Nitella sp. (stonewort) Nuphar lutea (yellow water-lily) Nuphar sp. (yellow water-lily) Nymphaea odorata (fragrant waterlily) Nymphaea sp. (water lily) Potamogeton amplifolius (large-leaf pondweed) Potamogeton natans (floating leaf pondweed) Potamogeton robbinsii (fern leaf pondweed) Potamogeton sp (thin leaved) (thin leaved pondweed) Potamogeton zosteriformis (eel-grass pondweed) Scirpus sp. (bulrush) Typha sp. (cat-tail) Utricularia inflata (big floating bladderwort) Utricularia sp. (bladderwort) Vallisneria americana (water celery) unknown plant (unknown)

Data collected and provided by Washington Department of Ecology's Lake Monitoring Program (Maggie Bell-McKinnon, phone 360- 407-6124).

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