MARSHALL LAKE -- PEND OREILLE COUNTY: 1995

Size (acres)                         194
Maximum Depth (feet)                  92
Mean Depth (feet)                     67
Lake Volume (acre-feet)            12998
Drainage Area (square miles)        4.82
Altitude (feet)                     2750
Shoreline Length (miles)             3.5

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
95/05/17                   Lt Green     85          Calm   34.0     0.0  FIELD VISIT
95/08/23                                 0                 38.0     0.0  
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LABORATORY RESULTS
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                    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
95/05/17       E       4        0.14        1.0            1U        1U                                          
95/05/17       H       8        0.10                                                                             
95/08/23       E      11        0.10        0.5U           1U        1U                                          
95/08/23       H      11        0.11                                                                             
________________________________________________________________________________________________________________________
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
Waterweed (Elodea canadensis) and native milfoil (Myriophyllum sp.) fragments were
observed floating.    

TROPHIC STATUS
Estimated Trophic State:                                 Oligotrophic
Mean Trophic State Index (Secchi):                       25N* (Oligotrophic)
Mean Trophic State Index (Total Phosphorus):             39 (Oligo-mesotrophic)
Mean Trophic State Index (Chlorophyll a):                28J* (Oligotrophic)

*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
Marshall Lake is an oligotrophic lake.  Phosphorus concentrations are quite high for
an oligotrophic lake, however, there doesn't appear to be any biological response to
the elevated phosphorus concentrations--the chlorophyll and macrophyte communities
appear to be quite sparce.

COMMENTS FROM 94/08/01 AQUATIC PLANT SURVEY
plants may be deeper.  sunny, slight breeze.  No plants at launch, macrophytes mostly
only at mouths of inflowing creeks  Maximum depth of plant growth:  6.0M. 

AQUATIC PLANT LIST  (This list may be from multiple years and sources.)
Callitriche verna (spring water-starwort)  Chara sp. (muskwort)  
Elodea canadensis (common elodea)  Glyceria borealis (northern
mannagrass)  Juncus sp. or Eleocharis sp. (small grass-like plants)  
Myriophyllum sibiricum (northern watermilfoil)  Potamogeton amplifolius 
(large-leaf pondweed)  Potamogeton foliosus (leafy pondweed)  Potamogeton
robbinsii (fern leaf pondweed)  Potamogeton sp (thin leaved) (thin leaved
pondweed)  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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