Table 3. Field and laboratory data collected during monthly samplings and basin-wide surveys, Clackamas River basin, Oregon, 2010–11.


[Sampling site locations are shown in figure 1. Constituents defined in table 6. Abbreviations: TPN, total particulate nitrogen; TPC, total particulate carbon; chl-a, chlorophyll-a; CRW, Clackamas River Water; DOC, dissolved organic carbon; DWTP; LO, City of Lake Oswego DWTP; DWTP, drinking-water treatment plant; DBP, disinfection by-product; FP, formation potential; RM, river mile; ~, approximately]


Sampling activity				Field parameters	Total nutrients	TPN / TPC	DOC	Dissolved nutrients	Optical properties2	Water-column chl-a	Benthic chl-a	DBPFP unfiltered3	DBPFP filtered3	DBPs4
Monthly	Basin-wide surveys	Targeted DBP sources1	Sampling sites
Main-stem Clackamas River / DWTP sites5
X	X		Clackamas River at Carter Bridge	X	X	X	X	X	X	X	X	X	X
X	X		Clackamas River at Estacada	X	X	X	X	X	X	X	X	X	X
	X		Clackamas River at Barton Bridge	X	X	X	X	X	X	X	X	X	X
	X		Clackamas River at Carver Bridge	X	X	X	X	X	X	X	X	X	X
X	X		CRW DWTP–Source water	X	X	X	X	X	X	X		X	X
X	X		CRW DWTP–Finished water				X		X					X
X	X		LO DWTP–Source water	X	X	X	X		X
X	X		LO DWTP–Finished water				X		X					X
Tributary sites
	X		Eagle Creek	X	X	X	X	X	X	X	X	X	X
	X		Deep Creek	X	X	X	X	X	X	X	X	X	X
	X		Clear Creek	X	X	X	X	X	X	X	X	X	X
	X		Rock Creek	X	X	X	X	X	X	X	X	X	X
	X		Sieben Creek	X	X	X	X	X	X	X	X	X	X
North Fork Reservoir sites
	X		1 - Surface (0.5 foot depth)	X	X	X	X	X	X	X		X	X
	X		2 - Mid-depth (mid-depth)	X	X	X	X	X	X	X		X	X
	X		3 - Release depth (~80 feet)	X	X	X	X	X	X	X		X	X
	X		4 - Near bottom (off bottom)	X	X	X	X	X	X	X		X	X
Upper Clackamas River/Forest
		X	Clackamas River upstream from Carter Bridge		X	X	X		X	X			X
		X	Alder Flat Trail		X	X	X		X	X			X

¹ Includes four types of benthic algae (periphyton) and water extracts from two types of forest leaf litter/soils (Douglas fir and Red alder).


² Optical properties include absorbance and fluorescence.


³ DBPFPs include determination of THMs and HAAs.


⁴ DBPs, DOC, and optical properties were analyzed in finished water during monthly samplings and basin-wide surveys.


⁵ U.S. Geological Survey operates three continuous water-quality monitors in the Clackamas River (fig. 1), including water temperature, specific conductance, dissolved oxygen, pH, turbidity (all stations), and water-column chlorophyll-a (at Estacada [RM 23.1] and Oregon City [RM 1.6] only). Data from the Oregon City station were used to indicate quality of source water for both DWTPs.

First posted February 11, 2013