ISLAND LAKE -- MASON COUNTY: 1997

Island Lake is located 2.5 miles north of Shelton. It drains via a swamp to Goldsborough Creek and Oakland Bay.

Size (acres)                         108
Maximum Depth (feet)                  31
Mean Depth (feet)                     21
Lake Volume (acre-feet)             2268
Drainage Area (square miles)        0.26
Altitude (feet)                      230
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
97/06/04  18.3  64.9  6.5  Lt Green      0   Light  Light  19.0     7.5  MEASURED FROM BOTTOM OF WHITE HOUSE BULKHEAD TO
                                                                         W.S.
97/06/20  18.9  66.0  6.5  Lt Green     10   Trace  Calm   19.0     2.0  WATER LEVEL MEASURED FROM TEH TOP OF BULKHEAD
                                                                         (DROPPING).  CLOUDINESS VARIED  FROM 0 - 10 %.
97/07/09  18.9  66.0  6.5  Lt Green    100   Mod    Breezy 17.0     0.0  WATER AT BASE OF BULKHEAD.  NO MORE PLACES TO
                                                                         MEASURE HEIGHT OF WATER.
97/08/05  23.3  73.9  6.5  Lt Green    100   None   Calm   18.0     0.0  THUNDER SHOWERS.
97/08/20  21.1  70.0  6.5  Lt Green    100   None   Light  15.0     0.0  MILFOIL SPREADING BEYOND THE BOAT LAUNCH.  RAIN
                                                                         BEGAN THIS A.M.  CONTINUED THROUGHOUT SAMPLING.
97/08/25                   Undefined     0                 16.0     0.0  WATER WAS A MODERATE GREEN.
97/09/03  20.0  68.0  6.5  Lt Green     50   Trace  Light  18.0     0.0  
97/09/24  17.8  64.0  6.5                0   None   Calm   14.0     0.0  
________________________________________________________________________________________________________________________
   
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
97/05/21       E       7                                                                                         
97/08/25       E       7        0.15        4.8                                                                  
________________________________________________________________________________________________________________________
E=epilimnion composite, H=hypolimnion composite.  Remarks codes: U = Below detection limits; J = Estimate.


SUMMARY OF VOLUNTEER SURVEY


There was no survey response for 1997.

FIELD OBSERVATIONS OF ECOLOGY STAFF
5-21-97 Eurasian milfoil submerged.  Low ionic pH kit reading one unit lower that
hydrolab.

8-25-97  Moderate blue-green algal bloom observed.

TROPHIC STATUS
Estimated Trophic State:                                 Oligo-mesotrophic
Mean Trophic State Index (Secchi):                       36 (Oligotrophic)
Mean Trophic State Index (Total Phosphorus):             32 (Oligotrophic)
Mean Trophic State Index (Chlorophyll a):                46 (Mesotrophic)

SUMMARY AND EXPLANATION OF TROPHIC STATE ASSESSMENT
Island Lake was very clear in 1997.  The low phosphorus concentrations and clear water
are indicative of an oligotrophic lake, however, the low hypolimnetic DO and moderate
chlorophyll concentrations are more characteristic of a mesotrophic lake, therefore,
Island Lake is assessed as oligo-mesotrophic.  


COMMENTS FROM 98/07/09 AQUATIC PLANT SURVEY
Calm, partly cloudy.  Lake treated with sonar June 24, 1998 - plants starting to show
some bleaching, especially the Najas.  Milfoil mostly still not showing signs, a
little bright green.  Milfoil very dense in many areas, mostly near the boat launch
and to the north.  East side still just individual plants with occasional dense
patches.  Bullfrogs heard.  Conducted habitat survey for Dave Hallock.  Maximum depth of
plant growth:  4.0M. 

AQUATIC PLANT LIST  (This list may be from multiple years and sources.)
Brasenia schreberi (watershield)  Carex lenticularis Chara sp. 
(muskwort)  Eleocharis sp. (spike-rush)  Elodea canadensis (common
elodea)  Iris pseudacorus (yellow flag)  Iris sp. (Iris)  Isoetes
lacustris (lake quillwort)  Myriophyllum spicatum (Eurasian water-milfoil)
Najas flexilis (common naiad)  Nitella sp. (stonewort)  Nymphaea
odorata (fragrant waterlily)  Potamogeton amplifolius (large-leaf pondweed)
Potamogeton foliosus (leafy pondweed)  Potamogeton gramineus 
(grass-leaved pondweed)  Potamogeton pusillus (slender pondweed)  
Potamogeton sp (thin leaved) (thin leaved pondweed)  Potamogeton sp. 
(pondweed)  Ranunculus aquatilis (water-buttercup)  Scirpus sp. 
(bulrush)

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

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