Quality-Control Samples

In order to interpret water-quality data, quality-control (QC) information is required to properly assess sample collection, processing, and analysis bias. The South Platte NAWQA study set aside approximately 15 percent of all samples collected for quality-control samples.

Three types of QC samples were collected: blanks, replicates, and spikes. Blanks were samples of inorganic- or organic-free water that had been processed through field equipment and sent to the laboratory to test for contamination from either field equipment or laboratory equipment. Replicates were multiple environmental samples (usually splits from the same sample) that had been sent to the laboratory in separate bottles to test analytical precision. Spikes were samples that had been "injected" with known concentrations of selected pesticides to test laboratory recovery of these analytes.

The data from blanks are entered in the data base under the sites at which they were processed. The parameters used to indicate the type of QC sample collected are called the "MEDIUM CODE" and the "SAMPLE TYPE." The medium code for surface-water QC is Q for blanks and R for replicates and spikes; the medium code for ground-water QC samples is Q for blanks and S for replicates and spikes; the medium code for sediment QC samples is W for replicates. The sample type is 1 for spikes, 2 for blanks, and 7 for replicates.

Surface-Water Quality-Control Sites
Column Descriptor List
06709610 South Platte River below Chatfield Reservoir	06759910 South Platte River at Cooper's Bridge near Balzac
	06764000 South Platte River at Julesburg
06713500 Cherry Creek at Denver	06765500 South Platte River at North Platte, NE
06714000 South Platte River at Denver
06718000 Clear Creek below Idaho Springs	394443105235000 Clear Creek near Idaho Springs
06719505 Clear Creek at Golden	394839104570300 Sand Creek at mouth near Commerce City
06720000 Clear Creek at Derby	394938104565300 South Platte River above Clear Creek near Commerce City
06720500 South Platte River at Henderson	400001104493600 South Platte River at Rd 2 near Bighton
06720820 Big Dry Creek at Westminster	400410105033100 Coal Creek at Rd 38 near Erie
06720990 Big Dry Creek at mouth near Ft Lupton	401330104505800 South Platte River near Platteville
06731000 St. Vrain Creek at Mouth near Platteville	401648103523500 Bijou Creek at Log Lane Village
06744000 Big Thompson River at mouth near La Salle	402114105350101 Big Thompson River below Moraine Park near Estes Park
06752000 Cache la Poudre River at mouth of canyon near Ft Collins	402331104292401 Crow Creek at mouth near Kuner
06752500 Cache la Poudre River near Greeley	402722103224100 South Platte River at Hwy 6 near Merino
06753400 Lonetree Creek at Carr
06753990 Lonetree Creek near Greeley
06754000 South Platte River near Kersey	404256103072500 South Platte River at Rd 40 near Sterling
06758500 South Platte River near Weldona	410658101212100 South Platte River at Paxton, NE
06759500 South Platte River at Ft Morgan
Ground-Water Quality-Control Sites
Column Descriptor List
392947105212601 XLN-20	401630104462902 FP-S2
393245105155000 XLN-27	401630104462903 FP-S3
393736105004001 URBLUS-3	401750104143101 SB00406120CAB
393827105244701 XLN-17	401841104432301 DU-8
393922105031201 URBLUS-5	401841104464601 FP-W1
394234104595301 URBLUS-11	401841104464603 FP-W3
394236104594903 P-11B	401844104450101 FP-E4
394236104594906 MW-13	401844104450106 FP-E6
394236104595301 P-1	402006104465301 FP-R1
394236104595302 P-2	402016104465508 SPLT1B-48
394236104595303 P-2T	402016104465510 SPLT1C-96
394236104595304 P-2B	402016104465511 SPLT1B-96
394236104595306 P-4	402115104432001 FP-D1
394236104595307 P-5	402116104432002 SPLT2-PW48
394236104595309 P-6T	402116104432006 SPLT2A-48
394236104595314 MW-14	402131105330601 XLN-10
394418105011501 URBLUS-14	402328104380101 SB00506523BAD2
394548105475801 XLN-1	402538103242001 SB00505404ADD
394655105030901 URBLUS-22	402658104400001 SB00606533ABD1
394811105023201 URBLUS-24	403426103200401 SB00705317BCB1
394824105065001 URBLUS-25	404106103082201 SB00805201CCD
394830104564001 URBLUS-26	405658102231201 SB01104509CCC
394835105053301 URBLUS-29	410251102024201 SB01204232CDD
395314105281001 XLN-4	410722101162901 SB01303501CAC
400324105201201 XLN-18
Bed-Sediment Quality-Control Sites
Column Descriptor List
06720500 South Platte River at Henderson	06752500 Cache la Poudre River near Greeley
06752000 Cache la Poudre River at mouth of canyon near Ft Collins	06754000 South Platte River at Kersey