ROESIGER (SOUTH ARM) LAKE -- SNOHOMISH COUNTY: 1997

Size (acres)                         140
Maximum Depth (feet)                  70
Mean Depth (feet)                     22
Lake Volume (acre-feet)             3080
Drainage Area (square miles)        3.55
Altitude (feet)                      570
Shoreline Length (miles)             3.0

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 3
97/04/26  13.8  56.8  7.0  Lt Green     75   None   Calm   18.0    15.5  
97/06/03  -7.2  19.0  7.2  Lt Green    100   Heavy  Light  17.0    19.8  STALKS OF PLANTS SEEN.  WILL TAKE SAMPLES NEXT
                                                                         TRIP.
97/06/27  19.0  66.2  7.0  Undefined    90   Mod    Breezy 16.5    16.0  WATER COLOR WAS BETWEEN LIGHT GREEN AND
                                                                         YELLOW-GREEN.
97/08/18  25.0  77.0  7.0  Lt Green    100   None   Breezy 18.0   294.0  3 WEEKS OF 70 - 90 DEGREE AIR TEMPS.
97/09/09  22.0  71.6  7.0  Lt Green      0          Calm   20.0    24.8  DEEP SITE NOT AS CLEAR AS SHALLOW SITE.
97/09/11                   Lt Green    100   Trace  Calm   20.3     0.0  
97/11/11  10.0  50.0       Lt Green      0   None   Calm   18.0    15.0  HEAVY FROST IN THE MORNINGS.  RAIN DELAYED THE
                                                                         LAST SECCHI READING.
________________________________________________________________________________________________________________________
   
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 3
97/06/03       E       5                                                                                         
97/06/03       H       5                                                                                         
97/09/11       E       3        0.13        2.8                                                                  
97/09/11       H      28        0.39                                                                             
________________________________________________________________________________________________________________________
E=epilimnion composite, H=hypolimnion composite.  Remarks codes: U = Below detection limits; J = Estimate.


SUMMARY OF VOLUNTEER SURVEY

WATER QUALITY-----------------------------------------------------------------------
Overall water quality was excellent.  The worst problems were reported as: 
     1. algae   2. excessive aquatic plants
Sources of actual or potential problems includes: 
     GARBAGE FROM FISHERMEN AND FIREWORKS
Were there days (and how many) when poor water quality impaired
      Fishing - NO(0)        Swimming - NO(0)        Aesthetics - NO(0) 
MANAGEMENT--------------------------------------------------------------------------
Did the lake receive chemical treatments this year?                NO
Were fish stocked this year?                                       YES
Any lake groups present (such as a lake association)?              YES
Any lake management activities this year?                          NO
OTHER-------------------------------------------------------------------------------
How many homes/new homes are there on the lake shore? 386            
Changes since last year? VERY LITTLE CHANGE
Lake Uses and Facilities at the lake include: 
     swimming  fishing  motor boating  jet skiing  picnic facilities  parks
The percent of the lakeshore that is sewered:                      0  
Motor boat restrictions include: 35 mph speed restrictionno wake restriction SKI HOURS
                                 IN SUMMER.

FIELD OBSERVATIONS OF ECOLOGY STAFF
Blue-green algae was observed in moderate amounts near the surface of the lake.

TROPHIC STATUS
Estimated Trophic State:                                 Oligo-mesotrophic
Mean Trophic State Index (Secchi):                       35 (Oligotrophic)
Mean Trophic State Index (Total Phosphorus):             21 (Oligotrophic)
Mean Trophic State Index (Chlorophyll a):                41 (Oligo-mesotrophic)

SUMMARY AND EXPLANATION OF TROPHIC STATE ASSESSMENT
Although Lake Roesiger (South Arm) possesses many of the same properties as the North
Arm of the lake, there is a significant DO sag in the summer and chlorophyll
concentrations are elevated to the mesotrophic range, therefore, an oligo-mesotophic
assessment is appropriate.

COMMENTS FROM 98/08/06 AQUATIC PLANT SURVEY
Cloudy, breeze, sunny later.  WDFW planted steelhead fry today.  Ducks and many small
fish observed.  Surveyed shoreline and sorkled boatlaunch area looking for milfoil,
found several scattered plants.  2 Purple loosestrife plants at north end, removed
heads and broke off at the base.

AQUATIC PLANT LIST  (This list may be from multiple years and sources.)Carex
unilateralis (one-sided sedge)  Elodea canadensis (common elodea)  
Elodea nuttallii (Nuttall's waterweed)  Iris pseudacorus (yellow flag)  
Isoetes sp. (quillwort)  Ludwigia palustris (water-purslane)  
Myriophyllum spicatum (Eurasian water-milfoil)  Nitella sp. (stonewort)
Nuphar sp. (yellow water-lily)  Nymphaea odorata (fragrant waterlily)  
Nymphaea sp. (water lily)  Potamogeton epihydrus (ribbonleaf pondweed)  
Potamogeton sp (thin leaved) (thin leaved pondweed)  Sagittaria graminea
(slender arrowhead)  Scirpus sp. (bulrush)  Typha sp. (cat-tail)  
Utricularia sp. (bladderwort)  Utricularia vulgaris (common bladderwort)
Vallisneria americana (water celery)

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

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