STUDY NUMBER ; 8.1 



ORGANIZATION ; Idaho Department of Health and Welfare (IDHW) 

 - Division of Environment (DOE) 



TITLE OF STUDY ; Clark Fork River/Lake Pend Oreille Water Quality 

 Study 



CONTACT ( S ) ; Mike Beckwith, Idaho Division of Environment 



(IDHW-DOE), Coeur d' Alene - (208) 667-3524 



Ed Tulloch, Idaho Division of Environment (IDHW- 

 DOE), Coeur d' Alene - (208) 667-3524 



OBJECTIVE ; Define baseline flow, sediment, nutrient and heavy 

 metal contributions to Lake Pend Oreille by the Clark Fork River; 

 assess ambient limnological conditions within the lake. 



DURATION ; July 1984 - Indefinite 



CURRENT STATUS ; Sampling has been conducted at two river sta- 

 tions--the Clark Fork River near its mouth at Cabinet Gorge Dam 

 (lake inlet) and the Pend Oreille River near Dover, Idaho. Five 

 lake stations have been sampled off the Clark Fork River delta, 

 at mid-point, in the southern and northern "arms," and at the 

 head of the outlet "arm" (Pend Oreille River). 



Sampling frequencies have been; 



River station--weekly May-July and monthly during rest of 

 year 



Lake stations--late April, early June, mid July, late Au- 

 gust, late September. 



Parameters analyzed include; 



Heavy metals (total recoverable); Cu, Zn, As, and Cd. 

 River samples only (lake samples are below detection limits) 



Nutrients; ammonia, nitrate, kjeldahl nitrogen, total phos- 

 phorus, orthophosphorus 



Others: Ca, Mg, alkalinity, hardness silica, turbidity, 

 total and fecal coliforms and phytoplankton. 



Additional parameters for the lake samples include chloro- 

 phyll-a and secchi disk transparency and profiles (down to 50 

 meters) for temperature, dissolved oxygen, pH and specific con- 

 ductivity. Algal assays have also been conducted on lake samples 

 in 1985 and 1986. 



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