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environmental information > river & stream WQ monitoring > state network >

Water quality monitoring station

33A050 - Snake R nr Pasco

Results that exceed water quality criteria or the usual range of data (since October, 1996)

Results that exceeded water quality standards criteria

The Department of Ecology places limits on how much pollution is allowed in our rivers to protect public health and enjoyment, and to support fish, shellfish, and wildlife (WAC 173-201A). Individual results for temperature, pH, oxygen, fecal coliform bacteria, and metals (where sampled) that are higher than these criteria are listed below. (The standards do not contain criteria for other types of water quality constituents.) This table includes only results from our monthly monitoring program. Results from other monitoring, such as continuous monitoring for temperature, are not evaluated here.

Exceeding a criterion does not necessarily mean the water quality standard has been violated. Often, other �pollution� conditions must exist for a stream segment to be in violation of water quality standards. In some cases, standards require that the source of pollution be human activities rather than natural causes. Also, more than a single result exceeding a criterion may be required.

Washington's Water Quality Standards were amended in November, 2006. Data in the tables below are based on the older standards through 2008. Data collected after 2008 are based on the ammended standards, excluding supplemental temperature criteria. We are currently working on incorporating supplemental temperature criteria into our evaluation procedures.

date	time	units	criterion	result	remark	% exceed
Fecal Coliform Bacteria (exceeding the ten percent criterion)
4/16/1997	08:15	#/100ml	200	310	J	55
Oxygen
date	time	units	criterion	result	remark	% exceed
9/15/2009	10:25	mg/L	8	7.6		5
9/12/2007	12:38	mg/L	8	7.6		4
9/12/2001	11:40	mg/L	8	7.6		5
8/8/2001	11:30	mg/L	8	7.8		3
9/8/1998	19:30	mg/L	8	7.8		3
pH
date	time	units	criterion	result	remark	% exceed
4/5/2005	15:32	pH	8.5	8.9		4
Temperature
date	time	units	criterion	result	remark	% exceed
9/15/2009	10:25	deg C	20	20.3		2
8/18/2009	11:47	deg C	20	21.3		7
8/11/2008	07:25	deg C	20	20.3		2
9/12/2007	12:38	deg C	20	20.8		4
8/13/2007	12:10	deg C	20	22.5		12
7/10/2007	13:20	deg C	20	23.3		17
7/18/2006	12:08	deg C	20	22.1		11
8/2/2005	12:15	deg C	20	22.2		11
7/12/2005	13:30	deg C	20	20.7		3
8/4/2004	14:05	deg C	20	22.4		12
7/14/2004	14:10	deg C	20	21.6		8
8/6/2003	11:35	deg C	20	21.5		8
8/7/2002	17:45	deg C	20	21.8		9
8/8/2001	11:30	deg C	20	21		5
8/9/2000	12:45	deg C	20	20.5		2
9/8/1998	19:30	deg C	20	21.5		8
8/12/1998	08:45	deg C	20	20.8		4
8/13/1997	19:20	deg C	20	22.2		11

Results that contrast strongly with historical data

Results exceeding the usual range of data (defined as 2 standard deviations beyond the mean value for a station based on data from the same three-month period over the previous six years) are shown below. A certain percentage of results will always be listed in this report. Inclusion here does not necessarily indicate something unique is occurring in the watershed.

date	time	units	result	remark	QMEAN	QSD	QDP
Ammonia-Nitrogen
3/6/2007	11:47	mg/L	0.047		1.529412E-02	1.217972E-02	17
11/13/2006	12:45	mg/L	0.01	U	2.422222E-02	7.079382E-03	17
10/10/2006	13:01	mg/L	0.01	U	2.422222E-02	7.079382E-03	17
2/7/2006	11:43	mg/L	0.04		1.529412E-02	1.217972E-02	17
12/6/2005	11:56	mg/L	0.01	U	2.422222E-02	7.079382E-03	17
11/9/2005	15:33	mg/L	0.01	U	2.422222E-02	7.079382E-03	17
12/7/2004	15:35	mg/L	0.01	U	2.422222E-02	7.079382E-03	17
10/10/2001	14:50	mg/L	0.036	J	0.013	0.005	18
7/11/2001	13:30	mg/L	0.047		0.018	0.012	18
9/7/1999	17:00	mg/L	0.05		0.018	0.012	18
10/13/1998	16:30	mg/L	0.192		0.013	0.005	18
5/14/1997	08:20	mg/L	0.064		0.021	0.016	18
Barometric Pressure
date	time	units	result	remark	QMEAN	QSD	QDP
9/12/2006	11:50	mm/Hg	758.444		743.8391	5.990838	18
7/18/2006	12:08	mm/Hg	759.46		743.8391	5.990838	18
2/7/2006	11:43	mm/Hg	767.842		748.7472	6.788884	17
12/6/2005	11:56	mm/Hg	770.128		747.4073	7.579319	18
11/9/2005	15:33	mm/Hg	763.524		747.4073	7.579319	18
10/4/2005	12:39	mm/Hg	766.318		747.4073	7.579319	18
9/13/2005	13:10	mm/Hg	759.714		743.8391	5.990838	18
8/2/2005	12:15	mm/Hg	758.19		743.8391	5.990838	18
7/12/2005	13:30	mm/Hg	757.174		743.8391	5.990838	18
3/8/2005	12:02	mm/Hg	762.762		748.7472	6.788884	17
2/8/2005	13:12	mm/Hg	765.81		748.7472	6.788884	17
9/13/2004	13:20	mm/Hg	731.012		745.0773	5.479276	18
3/5/2003	11:30	mm/Hg	734.568		753.212	4.857418	17
1/8/2003	11:25	mm/Hg	741.934		753.212	4.857418	17
12/18/2002	12:20	mm/Hg	734.314		753.1519	7.527657	18
Conductivity
date	time	units	result	remark	QMEAN	QSD	QDP
2/4/2009	08:36	umhos/cm	224		291	31.42498	18
9/12/2007	12:38	umhos/cm	210		131.7222	35.83427	18
4/5/2005	15:32	umhos/cm	286		136.2222	58.1353	18
7/9/2003	10:15	umhos/cm	83		146.2778	31.34402	18
7/10/2002	16:30	umhos/cm	80		149.6111	26.83312	18
4/3/2002	16:45	umhos/cm	264		142.3889	50.37056	18
4/11/2001	12:10	umhos/cm	276		147.778	56.038	18
Fecal Coliform Bacteria
date	time	units	result	remark	QMEAN	QSD	QDP
8/18/2009	11:47	#/100ml	28		4.5	8	16
3/2/2009	08:50	#/100ml	2		1.166667	0.3834825	18
2/4/2009	08:36	#/100ml	2		1.166667	0.3834825	18
1/7/2009	08:35	#/100ml	3		1.166667	0.3834825	18
1/9/2007	13:32	#/100ml	2	J	1.176471	0.3929526	17
1/10/2006	13:15	#/100ml	2		1.176471	0.3929526	17
8/9/2000	12:45	#/100ml	190	J	35.167	68.55	18
12/10/1997	08:40	#/100ml	22		5.25	5.837	16
4/16/1997	08:15	#/100ml	310	J	37.167	81.514	18
Flow
date	time	units	result	remark	QMEAN	QSD	QDP
7/6/1999	14:50	CFS	92000		32993.33	22260.9	15
7/15/1997	18:30	CFS	102500		32993.33	22260.9	15
6/11/1997	09:30	CFS	178000		81620	46001.04	15
5/14/1997	08:20	CFS	204600		81620	46001.04	15
3/12/1997	08:25	CFS	121600		43596.67	29137.41	15
Nitrate+Nitrite-Nitrogen
date	time	units	result	remark	QMEAN	QSD	QDP
4/6/2009	08:55	mg/L	1.18		0.314	0.2602537	18
10/5/2004	15:42	mg/L	0.167		0.5752778	0.1873288	18
10/8/2003	14:05	mg/L	0.197		0.6013333	0.1858905	18
1/8/2003	11:25	mg/L	0.595		1.044588	0.1962887	17
Nitrate-Nitrite
date	time	units	result	remark	QMEAN	QSD	QDP
4/3/2002	16:45	mg/L	1.15		0.3270555	0.2829827	18
4/11/2001	12:10	mg/L	1.28		0.455	0.332	18
Oxygen
date	time	units	result	remark	QMEAN	QSD	QDP
4/11/2006	11:20	mg/L	13.4		11.68278	0.8175415	18
3/8/2006	13:15	mg/L	13.7		12.42941	0.592563	17
4/5/2005	15:32	mg/L	13.6		11.68278	0.8175415	18
3/10/2004	14:30	mg/L	13.5		12.29	0.5365049	17
9/12/2001	11:40	mg/L	7.6		9.428	0.839	18
6/13/2001	11:50	mg/L	9.7		12.3	1.061	18
pH
date	time	units	result	remark	QMEAN	QSD	QDP
7/18/2006	12:08	pH	8.5		7.928333	0.1784327	18
4/5/2005	15:32	pH	8.9		8.026667	0.2185783	18
3/10/2004	14:30	pH	8.4		8.0075	0.173954	16
8/7/2002	17:45	pH	7.5	J	8.033334	0.1992929	18
6/12/2002	15:01	pH	7.6		8.112223	0.2362341	18
12/15/1999	12:40	pH	7.8		8.122	0.14	18
11/17/1999	10:35	pH	7.7		8.122	0.14	18
8/3/1999	16:05	pH	7.7		8.161	0.215	18
3/17/1999	10:50	pH	7.6		8.128	0.227	18
Phosphorus, Sol Reactive
date	time	units	result	remark	QMEAN	QSD	QDP
4/6/2009	08:55	mg/L	0.0426		2.001667E-02	9.142612E-03	18
9/12/2007	12:38	mg/L	0.0348		1.728333E-02	8.163639E-03	18
3/8/2006	13:15	mg/L	0.0685		4.657647E-02	1.077715E-02	17
3/6/2002	15:07	mg/L	0.0438		7.458823E-02	1.214204E-02	16
11/14/2001	16:03	mg/L	0.0724		0.042	0.013	16
11/17/1999	10:35	mg/L	0.096		0.042	0.013	16
10/16/1996	11:50	mg/L	0.009		0.042	0.013	16
Phosphorus, Total
date	time	units	result	remark	QMEAN	QSD	QDP
12/18/2002	12:20	mg/L	0.061		0.1182222	2.786562E-02	17
10/16/2002	12:30	mg/L	0.053		0.1182222	2.786562E-02	17
11/17/1999	10:35	mg/L	0.132		0.061	0.025	17
2/12/1997	10:20	mg/L	0.192		0.079	0.043	17
12/11/1996	09:00	mg/L	0.932		0.061	0.025	17
Suspended Solids
date	time	units	result	remark	QMEAN	QSD	QDP
6/1/2009	08:45	mg/L	18		8.333333	3.613699	18
11/2/2004	14:50	mg/L	19		4.055555	1.392088	18
5/12/1999	13:25	mg/L	35		15.833	8.234	18
Temperature
date	time	units	result	remark	QMEAN	QSD	QDP
7/7/2008	08:08	deg C	17.6		20.90588	1.376804	17
7/10/2007	13:20	deg C	23.3		19.72778	1.624375	18
1/10/2006	13:15	deg C	0		4.276471	1.227054	17
12/6/2005	11:56	deg C	0		11.2	4.192571	18
7/6/1999	14:50	deg C	15.9		19.867	1.284	18
Total Persulf Nitrogen
date	time	units	result	remark	QMEAN	QSD	QDP
4/6/2009	08:55	mg/L	1.3		0.4257222	0.2838354	18
10/5/2004	15:42	mg/L	0.309		0.7227222	0.1969684	18
7/10/2002	16:30	mg/L	0.113		0.3038889	8.202431E-02	18
4/3/2002	16:45	mg/L	1.34		0.4893889	0.2942724	18
10/10/2001	14:50	mg/L	0.316	J	0.735	0.208	12
4/11/2001	12:10	mg/L	1.42		0.484	0.229	12
Turbidity
date	time	units	result	remark	QMEAN	QSD	QDP
6/11/1997	09:30	NTU	23		10.161	5.428	18

Note: QMEAN, QSD, and QDP are the quarterly mean, standard deviation, and number of data points for the last six years, where available, for the station shown.

Washington State Department of Ecology

Data users please read disclaimer.

Questions or comments on content may be sent to Dave Hallock
Questions or comments on presentation may be sent to Steve Barrett.