| Summary: | Sixteen sites were established at south, mid, and north lake areas on Pend Oreille Lake, Idaho in 1989. Information on inshore water chemistry, bacteria, physical/chemical conditions, and productivity of attached benthic algae and aquatic macrophytes was gathered. Sites were sampled in July, August, and September 1989. Mean inshore total phosphorus was greater near developed areas than undeveloped areas all three months. Highest fecal coliform counts were seen in August at Bayview (south lake) (50/100ml) and Trestle Creek (10/100ml), two developed sites. Conversely, fecal streptococci counts were highest at Warren Island (greater than 100/100ml) and Talache (72/100ml), two relatively undeveloped sites. Maximum summer transparencies were found in mid and south lake areas, up to 11.1 m. Shallow north bays had the lowest transparency readings with a minimum of 0,35 m. Mean chlorophyll a values from attached algae correlated with level of shoreline development or higher values at more developed sites and lower values at less developed sites. Total (Aug. plus Sept.) mean chlorophyll a on artificial substrates was 4.3 mg/m^2 for developed sites vs 2.1 mg/m^2 at undeveloped sites. August and September aquatic macrophyte data show highest production 3.0 to 4.9 m deep, with a rapid decline from 4.9 to 6.7 m. Production was found to be at or near zero from 6.7 to 10.1 m deep.
|
|---|