Cranberry Lake is located in Deception Pass State Park, at the north end of Whidbey Island. The inflow in intermittent and the lake drains to Rosario Strait. The lake level is stabilized by a dam. No motor boats are allowed on the lake. Cranberry Lake was monitored by Ecology staff only.
Size (acres) 125 Maximum Depth (feet) 25 Mean Depth (feet) 13 Lake Volume (acre-feet) 1625 Drainage Area (square miles) 0.61 Altitude (feet) 20 Shoreline Length (miles) 2.8
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 1996. ________________________________________________________________________________________________________________________
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 96/06/05 E 35 0.91 4.1 160 1.6J 96/06/05 H 64 0.96 96/08/21 E 89 0.86 17.6 1300J 4 1.1 96/08/21 H 186 1.00 ________________________________________________________________________________________________________________________ E=epilimnion composite, H=hypolimnion composite. Remarks codes: U = Below detection limits; J = Estimate.
SUMMARY OF VOLUNTEER SURVEY There was no survey response for 1996. FIELD OBSERVATIONS OF ECOLOGY STAFF There is a resident bald eagle. The water is tannin colored. The summer visit revealed a very green water color. The algae was so thick along some of the shoreline that 2 would-be swimmers were discouraged with the water quality and left.
TROPHIC STATUS Estimated Trophic State: Eutrophic Mean Trophic State Index (Secchi): 45N* (Mesotrophic) Mean Trophic State Index (Total Phosphorus): 69 (Eutrophic) Mean Trophic State Index (Chlorophyll a): 54 (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 Cranberry Lake is classified as eutrophic. The lake is very shallow with abundant macrophyte populations. The rich flora populations support the phosphorus and chlorophyll TSIs, all which support a eutrophic classification.
COMMENTS FROM 96/09/05 AQUATIC PLANT SURVEY Visited shore access to check on milfoil species, all looks native. Cloudy, calm, lots of waterfowl
AQUATIC PLANT LIST (This list may be from multiple years and sources.) Ceratophyllum sp. (coontail) Chara sp. (muskwort) Eleocharis palustris (common spike-rush) Eleocharis sp. (spike-rush) Elodea canadensis (common elodea) Juncus sp. (rush) Lemna trisulca (star duckweed) Myriophyllum sibiricum (northern watermilfoil) Myriophyllum sp. (water-milfoil) Najas flexilis (common naiad) Nitella sp. (stonewort) Nuphar polysepala (spatter-dock, yellow water-lily) Potamogeton amplifolius (large-leaf pondweed) Potamogeton pectinatus (sago pondweed) Potamogeton praelongus (whitestem pondweed) Potamogeton zosteriformis (eel-grass pondweed) Scirpus sp. (bulrush) Typha sp. (cat-tail) unknown plant (unknown)
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