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

Water quality monitoring station*

49B070 - Similkameen R @ Oroville

* This station is also a flow monitoring station

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)
7/9/2002	08:40	#/100ml	200	290		45
Oxygen
date	time	units	criterion	result	remark	% exceed
8/3/2009	09:00	mg/L	8	7.9		1
pH
date	time	units	criterion	result	remark	% exceed
10/7/2003	10:50	pH	8.5	8.6		1
8/11/1998	07:00	pH	8.5	8.6		1
Temperature
date	time	units	criterion	result	remark	% exceed
9/14/2009	09:20	deg C	17.5	19		9
8/3/2009	09:00	deg C	17.5	23.8		36
9/8/2008	08:15	deg C	18	18.6		3
8/4/2008	09:00	deg C	18	19.9		11
8/6/2007	07:05	deg C	18	20.9		16
8/7/2006	07:20	deg C	18	19.9		11
7/10/2006	07:00	deg C	18	20.4		13
8/1/2005	06:25	deg C	18	22.6		26
8/10/2004	10:02	deg C	18	21.2		18
9/9/2003	08:40	deg C	18	18.6		3
8/5/2003	08:02	deg C	18	20.7		15
7/8/2003	08:31	deg C	18	19.5		8
8/15/2001	06:25	deg C	18	22.3		24
7/11/2001	06:50	deg C	18	22.1		23
9/8/1998	06:50	deg C	18	19.3		7
8/11/1998	07:00	deg C	18	21.2		18
8/12/1997	06:30	deg C	18	19.7		9

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
12/4/2006	07:25	mg/L	0.011		2.127778E-02	5.086025E-03	17
11/13/2006	07:15	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
10/2/2006	07:30	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
12/5/2005	07:30	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
11/7/2005	07:20	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
10/3/2005	07:20	mg/L	0.04		2.127778E-02	5.086025E-03	17
12/6/2004	07:15	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
12/8/2003	11:06	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
11/4/2003	10:14	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
10/7/2003	10:50	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
12/3/2002	08:30	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
11/5/2002	08:15	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
10/8/2002	09:30	mg/L	0.01	U	2.127778E-02	5.086025E-03	17
11/13/2001	09:02	mg/L	0.012		0.01	0	18
10/5/1999	08:55	mg/L	0.031		0.01	0	18
9/7/1999	06:40	mg/L	0.036		0.01	0.001	18
8/3/1999	06:40	mg/L	0.026		0.01	0.001	18
7/6/1999	06:40	mg/L	0.026		0.01	0.001	18
5/11/1999	08:00	mg/L	0.026		0.012	0.006	18
10/13/1998	06:20	mg/L	0.19		0.01	0	18
5/13/1997	06:15	mg/L	0.033		0.012	0.006	18
Arsenic, Tot Rec
date	time	units	result	remark	QMEAN	QSD	QDP
9/11/2006	06:40	ug/L	6.99		3.8525	1.501674	4
5/1/2006	07:10	ug/L	7.37		3.105	1.191449	6
8/5/2003	08:02	ug/L	5.61		3.495	1.044398	4
Barometric Pressure
date	time	units	result	remark	QMEAN	QSD	QDP
9/14/2009	09:20	mm/Hg	724.916		738.5897	5.053222	18
7/7/2008	09:00	mm/Hg	726.948		739.8597	4.485054	18
4/4/2005	07:05	mm/Hg	725.424		737.2936	5.472223	18
1/3/2005	07:10	mm/Hg	709.422		741.2856	12.18585	18
12/3/2002	08:30	mm/Hg	719.582	J	739.7781	8.764063	18
11/5/2002	08:15	mm/Hg	716.788	J	739.7781	8.764063	18
10/8/2002	09:30	mm/Hg	717.296		739.7781	8.764063	18
Conductivity
date	time	units	result	remark	QMEAN	QSD	QDP
4/6/2009	08:15	umhos/cm	232		123.4444	43.83555	18
4/7/2008	08:45	umhos/cm	226		123.4444	43.83555	18
11/13/2006	07:15	umhos/cm	135		199.1111	28.1548	18
3/14/2005	06:50	umhos/cm	133		198.6111	24.26118	18
2/7/2005	07:25	umhos/cm	146		198.6111	24.26118	18
12/6/2004	07:15	umhos/cm	142	J	199.1111	28.1548	18
11/1/2004	07:24	umhos/cm	109		195.5556	29.98671	18
7/9/2002	08:40	umhos/cm	76		162.1111	41.47556	18
4/4/2001	08:40	umhos/cm	216		118.611	34.988	18
10/5/1999	08:55	umhos/cm	244		182.167	27.618	18
7/6/1999	06:40	umhos/cm	92		163.778	34.693	18
4/13/1999	07:40	umhos/cm	267		118.611	34.988	18
4/7/1998	06:30	umhos/cm	194		118.611	34.988	18
4/15/1997	06:55	umhos/cm	197		118.611	34.988	18
Fecal Coliform Bacteria
date	time	units	result	remark	QMEAN	QSD	QDP
6/5/2007	07:25	#/100ml	130		14.88889	15.54458	18
11/13/2006	07:15	#/100ml	10	J	2.294118	1.7946	17
5/1/2006	07:10	#/100ml	60		14.88889	15.54458	18
10/3/2005	07:20	#/100ml	40	J	2.294118	1.7946	17
4/13/2004	11:06	#/100ml	57		12.22222	11.53285	18
3/9/2004	10:58	#/100ml	8		1.0625	0.25	16
7/9/2002	08:40	#/100ml	290		10.22222	7.2967	18
5/13/1997	06:15	#/100ml	92		16.667	20.987	18
10/15/1996	08:05	#/100ml	12		3.611	3.852	18
Flow
date	time	units	result	remark	QMEAN	QSD	QDP
7/6/1999	06:40	CFS	8590		1417.733	999.638	15
7/15/1997	06:20	CFS	4000		1417.733	999.638	15
5/13/1997	06:15	CFS	15000		5942.5	4500.519	18
Hardness
date	time	units	result	remark	QMEAN	QSD	QDP
12/15/1998	07:50	mg/L	112		90.25	7.5	4
Nitrate+Nitrite-Nitrogen
date	time	units	result	remark	QMEAN	QSD	QDP
6/1/2009	08:05	mg/L	0.021		1.144444E-02	2.66176E-03	18
6/2/2008	09:47	mg/L	0.029		1.144444E-02	2.66176E-03	18
2/11/2008	09:15	mg/L	0.067		1.705556E-02	1.118545E-02	18
1/7/2008	08:40	mg/L	0.05		1.705556E-02	1.118545E-02	18
8/6/2007	07:05	mg/L	0.02		1.022222E-02	9.42809E-04	18
6/5/2007	07:25	mg/L	0.016		1.088889E-02	2.083235E-03	18
4/2/2007	07:00	mg/L	0.019		1.088889E-02	2.083235E-03	18
12/4/2006	07:25	mg/L	0.07		2.327778E-02	1.716291E-02	18
Nitrate-Nitrite
date	time	units	result	remark	QMEAN	QSD	QDP
12/3/2002	08:30	mg/L	0.062		2.216667E-02	1.723966E-02	18
1/12/1999	08:05	mg/L	0.149		0.029	0.019	14
7/15/1997	06:20	mg/L	0.07		0.015	0.014	18
3/11/1997	05:35	mg/L	0.073		0.029	0.019	14
Oxygen
date	time	units	result	remark	QMEAN	QSD	QDP
8/3/2009	09:00	mg/L	7.9		9.421667	0.7339759	18
5/5/2008	08:30	mg/L	10.4		12.06167	0.6249071	18
3/9/2004	10:58	mg/L	11.7		13.49167	0.8346909	18
12/8/2003	11:06	mg/L	14.9		12.42944	1.217159	18
10/7/2003	10:50	mg/L	10.2		12.34111	1.050887	18
10/8/2002	09:30	mg/L	10.2		12.34111	1.050887	18
7/9/2002	08:40	mg/L	11.2		9.460556	0.8063095	18
9/5/2001	06:25	mg/L	8.7		9.683	0.45	18
8/15/2001	06:25	mg/L	8.4		9.683	0.45	18
7/11/2001	06:50	mg/L	8.5		9.683	0.45	18
7/6/1999	06:40	mg/L	11.5		9.683	0.45	18
8/11/1998	07:00	mg/L	8.1		9.683	0.45	18
pH
date	time	units	result	remark	QMEAN	QSD	QDP
5/4/2009	08:45	pH	8.2		7.635	0.2345772	18
4/6/2009	08:15	pH	8.3		7.635	0.2345772	18
5/5/2008	08:30	pH	8.2		7.635	0.2345772	18
4/7/2008	08:45	pH	8.4		7.635	0.2345772	18
3/5/2007	07:05	pH	7.3		7.987778	0.2479932	18
2/12/2007	07:15	pH	7.3		7.987778	0.2479932	18
1/8/2007	07:40	pH	7.3		7.987778	0.2479932	18
4/10/2006	07:15	pH	7.2		7.846667	0.2627471	17
10/3/2005	07:20	pH	7.4		8.041111	0.2671833	18
3/14/2005	06:50	pH	7.3		7.987778	0.2479932	18
2/7/2005	07:25	pH	7.2		7.987778	0.2479932	18
1/3/2005	07:10	pH	7.2		7.987778	0.2479932	18
12/6/2004	07:15	pH	7.4		8.041111	0.2671833	18
8/6/2002	08:47	pH	7.6		8.157778	0.2387851	18
7/9/2002	08:40	pH	7.6		8.157778	0.2387851	18
8/3/1999	06:40	pH	7.7		8.194	0.204	18
7/6/1999	06:40	pH	7.7		8.194	0.204	18
3/16/1999	07:20	pH	7.2		8.107	0.305	14
12/9/1997	07:00	pH	7.3		8.071	0.341	17
11/4/1997	06:50	pH	7.1		8.071	0.341	17
Phosphorus, Sol Reactive
date	time	units	result	remark	QMEAN	QSD	QDP
8/6/2007	07:05	mg/L	0.0062		0.0041	9.573247E-04	18
12/4/2006	07:25	mg/L	0.011		4.327778E-03	8.301705E-04	18
11/13/2006	07:15	mg/L	0.014		4.327778E-03	8.301705E-04	18
1/3/2005	07:10	mg/L	0.011	J	4.538889E-03	1.429166E-03	18
11/1/2004	07:24	mg/L	0.003	U	4.627778E-03	6.595948E-04	18
10/4/2004	06:50	mg/L	0.003	U	4.627778E-03	6.595948E-04	18
12/8/2003	11:06	mg/L	0.003	U	4.627778E-03	6.595948E-04	18
10/7/2003	10:50	mg/L	0.003	U	4.788889E-03	5.497474E-04	18
9/9/2003	08:40	mg/L	0.0031		4.744445E-03	6.195086E-04	18
8/5/2003	08:02	mg/L	0.0032		4.744445E-03	6.195086E-04	18
7/8/2003	08:31	mg/L	0.0031		4.744445E-03	6.195086E-04	18
12/3/2002	08:30	mg/L	0.0035		4.788889E-03	5.497474E-04	18
9/10/2002	09:35	mg/L	0.0033		0.005	7.529297E-11	18
8/6/2002	08:47	mg/L	0.0041		0.005	7.529297E-11	18
7/9/2002	08:40	mg/L	0.003	U	0.005	7.529297E-11	18
3/5/2002	09:50	mg/L	0.003	U	0.00525	0.001	16
12/4/2001	09:45	mg/L	0.0037	J	0.008	0.002	17
10/9/2001	08:50	mg/L	0.003	UJ	0.008	0.002	17
Phosphorus, Total
date	time	units	result	remark	QMEAN	QSD	QDP
12/3/2002	08:30	mg/L	0.012		6.427778E-02	7.853905E-03	17
11/5/2002	08:15	mg/L	0.017		6.427778E-02	7.853905E-03	17
10/8/2002	09:30	mg/L	0.015		6.427778E-02	7.853905E-03	17
7/9/2002	08:40	mg/L	0.046		0.018	8.937693E-03	18
8/3/1999	06:40	mg/L	0.023		0.012	0.004	18
7/6/1999	06:40	mg/L	0.045		0.012	0.004	18
9/8/1998	06:50	mg/L	0.031		0.012	0.004	18
7/14/1998	07:20	mg/L	0.023		0.012	0.004	18
2/10/1998	07:05	mg/L	0.031		0.013	0.006	14
1/13/1998	07:05	mg/L	0.037		0.013	0.006	14
9/16/1997	06:30	mg/L	0.021		0.012	0.004	18
8/12/1997	06:30	mg/L	0.021		0.012	0.004	18
5/13/1997	06:15	mg/L	0.334		0.055	0.078	18
3/11/1997	05:35	mg/L	0.033		0.013	0.006	14
12/10/1996	06:15	mg/L	0.886		0.015	0.012	17
Suspended Solids
date	time	units	result	remark	QMEAN	QSD	QDP
12/5/2007	08:30	mg/L	15		3	4.297742	18
6/5/2007	07:25	mg/L	273		37.22222	42.76001	18
12/4/2006	07:25	mg/L	4		1.611111	0.8498366	18
11/13/2006	07:15	mg/L	19		1.611111	0.8498366	18
5/1/2006	07:10	mg/L	157	J	37.22222	42.76001	18
12/5/2005	07:30	mg/L	7		1.611111	0.8498366	18
6/6/2005	06:50	mg/L	377	J	37.22222	42.76001	18
2/7/2005	07:25	mg/L	9		2.5	1.543487	18
5/4/2004	10:40	mg/L	163		27.38889	27.43793	18
4/13/2004	11:06	mg/L	94		27.38889	27.43793	18
11/4/2003	10:14	mg/L	4		1.722222	0.7519039	18
7/9/2002	08:40	mg/L	88		6.944445	7.041659	18
7/6/1999	06:40	mg/L	30		5.333	4.201	18
7/15/1997	06:20	mg/L	14		5.333	4.201	18
5/13/1997	06:15	mg/L	293		55.333	74.297	18
Temperature
date	time	units	result	remark	QMEAN	QSD	QDP
8/3/2009	09:00	deg C	23.8		17.86667	2.734313	18
4/2/2007	07:00	deg C	5.2		9.277778	1.737664	18
3/9/2004	10:58	deg C	8.9		2.2	2.131004	18
10/7/2003	10:50	deg C	15.7		5.022222	3.333353	18
10/8/2002	09:30	deg C	13.3		5.022222	3.333353	18
8/15/2001	06:25	deg C	22.3		16.994	2.347	18
7/11/2001	06:50	deg C	22.1		16.994	2.347	18
9/7/1999	06:40	deg C	12		16.994	2.347	18
7/6/1999	06:40	deg C	12		16.994	2.347	18
Total Persulf Nitrogen
date	time	units	result	remark	QMEAN	QSD	QDP
1/7/2008	08:40	mg/L	0.15		8.305556E-02	2.938281E-02	18
12/4/2006	07:25	mg/L	0.16		0.0785	3.216547E-02	18
11/13/2006	07:15	mg/L	0.18		0.0785	3.216547E-02	18
1/9/2006	07:30	mg/L	0.17		7.511111E-02	2.796255E-02	17
10/3/2005	07:20	mg/L	0.16		0.0785	3.216547E-02	18
1/13/2004	10:30	mg/L	0.256		7.955556E-02	2.734986E-02	17
7/8/2003	08:31	mg/L	0.15		8.238889E-02	2.669686E-02	18
1/17/2001	09:05	mg/L	0.029		0.098	0.028	10
5/13/1997	06:15	mg/L	0.336		0.149	0.089	12
3/11/1997	05:35	mg/L	0.158		0.098	0.028	10
Turbidity
date	time	units	result	remark	QMEAN	QSD	QDP
8/6/2007	07:05	NTU	55		3.394444	5.002643	18
6/5/2007	07:25	NTU	130	J	14.11667	16.07147	18
2/12/2007	07:15	NTU	3.7		1.088889	0.441773	18
1/8/2007	07:40	NTU	3.6		1.088889	0.441773	18
12/4/2006	07:25	NTU	2.7		0.9222222	0.4531661	18
11/13/2006	07:15	NTU	12		0.9222222	0.4531661	18
5/1/2006	07:10	NTU	70		14.11667	16.07147	18
1/9/2006	07:30	NTU	2		1.088889	0.441773	18
2/7/2005	07:25	NTU	4.6		1.088889	0.441773	18
1/3/2005	07:10	NTU	2.7		1.088889	0.441773	18
5/4/2004	10:40	NTU	45		10.85	12.47903	18
4/13/2004	11:06	NTU	45		10.85	12.47903	18
7/9/2002	08:40	NTU	21		2.816667	2.347777	18
7/6/1999	06:40	NTU	10		2.561	2.3	18
5/13/1997	06:15	NTU	110		20.267	28.038	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.