BLACKMANS LAKE -- SNOHOMISH COUNTY: 1994

Blackmans Lake is located one mile north of Snohomish. A perennial stream flows into the lake from the north. Blackmans Lake drains via Swifty Creek to the Snohomish River.

Size (acres)                          57
Maximum Depth (feet)                  29
Mean Depth (feet)                     14
Lake Volume (acre-feet)              798
Drainage Area (square miles)        0.81
Altitude (feet)                      140
Shoreline Length (miles)             1.5

Contour Map

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


VOLUNTEER-COLLECTED SECCHI DATA
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Date      Temperature      Water      %Cloud Recent        Secchi Lake  
(Y/M/D)    (C)   (F)  pH   Color      Cover  Rain   Wind   (ft)   Ht(in) Abbrev. Comments
________________________________________________________________________________________________________________________
        STATION 1
94/06/04                   Grn-brown   100   None   Breezy 15.0     0.0  Green algae washed up on shore.
94/07/04  20.0  68.0  7.3                0   None   Light  12.5     0.0  Water color yellow-green.
94/08/27  21.7  71.1                     0   None   Breezy 10.0    29.0  
94/10/23  13.9  57.0                    75   Light  Calm   11.5     0.0  Water color yellow-green. Parking lot
                                                                         construction underway at Hill Park.
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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
94/06/04       E      22        0.23        4.5                                                                  
94/06/04       H      45        0.21                                                                             
94/08/27       E      24        0.34J       6.8                                                                  
94/08/27       H      98        0.58J                                                                            
        STATION 2
94/06/04       E      36        0.22        3.7                                                                  
94/08/27       E      23        0.30J       5.1                                                                  
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E=epilimnion composite, H=hypolimnion composite.  Remarks codes: U = Below detection limits; J = Estimate.


SUMMARY OF VOLUNTEER SURVEY


There was no survey response for 1994.

FIELD OBSERVATIONS OF ECOLOGY STAFF

There were no field observations recorded for BLACKMANS (SNOHOMISH) in 1994


TROPHIC STATUS
Estimated Trophic State:                                 Not Available
Mean Trophic State Index (Secchi):                       42N* (Mesotrophic)
Mean Trophic State Index (Total Phosphorus):             50 (Meso-eutrophic)
Mean Trophic State Index (Chlorophyll a):                46 (Mesotrophic)

*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

No summary analysis was performed for BLACKMANS (SNOHOMISH) in 1994


COMMENTS FROM 98/08/05 AQUATIC PLANT SURVEY
Sunny, breeze.  Much of shoreline with nice riparian areas.  Fewer submersed plants
along north side, more Nymphaea and algae 'pillows'.  Water clarity was good, plant
growth not excessive, but some signs of nutrient increase (such as algae).  Geese,
ducks and bullfrogs noticed using the water.  Small patch of purple loosestrife on
north shore.  Maximum depth of plant growth:  4.0M. 

AQUATIC PLANT LIST  (This list may be from multiple years and sources.)
Alisma plantago-aquatica (American water-plantain)  Ceratophyllum sp. 
(coontail)  Dulichium arundinaceum (Dulichium)  Eleocharis sp. 
(spike-rush)  Elodea canadensis (common elodea)  Iris pseudacorus 
(yellow flag)  Juncus sp. (rush)  Juncus sp. or Eleocharis sp. (small
grass-like plants)  Lythrum salicaria (purple loosestrife)  Najas
flexilis (common naiad)  Nitella sp. (stonewort)  Nuphar polysepala 
(spatter-dock, yellow water-lily)  Nymphaea odorata (fragrant waterlily)  
Phalaris arundinacia (reed canarygrass)  Potamogeton amplifolius 
(large-leaf pondweed)  Potamogeton pusillus (slender pondweed)  Potentilla
palustris (purple (marsh) cinquefoil)  Scirpus sp. (bulrush)  Typha
sp. (cat-tail)

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

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