SAN JUAN RIVER BASIN

09349800 PIEDRA RIVER NEAR ARBOLES, CO

LOCATION.--Lat 37°05'18", long 107°23'50", in NE14SW14 sec.21, T.33 N., R.5 W., Archuleta County, Hydrologic Unit 14080102, on left bank 2.5 mi upstream from Navajo Reservoir, 3.0 mi downstream from Ignacio Creek, and 4.6 mi northeast of Arboles Post Office.

DRAINAGE AREA.--629 mi2.

PERIOD OF RECORD.--August 1962 to current year. Gage 09350000 (Piedra River At Arboles) operated 1895-99 and 1910-27 at site 7.5 mi downstream at elevation 6,000 ft, published in WSP 1313. Low-flow records probably not equivalent. For a complete listing of historical data available for this site, see http://waterdata.usgs.gov/co/nwis/inventory/?site_no=09349800

GAGE.--Water-stage recorder with satellite telemetry, and crest-stage gage. Datum of gage is 6,147.52 ft above NGVD of 1929, Colorado State Highway Department benchmark.

REMARKS.--Records good except for estimated daily discharges, which are poor. Diversions for irrigation of about 2,800 acres upstream from station. Several measurements of specific conductance and water temperature were obtained and are published in the "Supplemental Water-Quality Data For Gaging Stations" section of this report.

EXTREMES OUTSIDE PERIOD OF RECORD.--Major floods occurred Sept. 5 or 6, 1909, and Oct. 5, 1911.

Discharge, cubic feet per second 

WATER YEAR OCTOBER 2002 TO SEPTEMBER 2003

DAILY MEAN VALUES

DAY	OCT	NOV	DEC	JAN	FEB	MAR	APR	MAY	JUN	JUL	AUG	SEP
1	80	77	56	e29	21	28	187	603	1,100	63	53	81
2	84	75	54	e27	24	27	223	564	981	57	53	65
3	108	76	51	e26	25	27	204	548	918	55	45	65
4	115	69	54	e29	21	29	172	561	810	52	43	70
5	104	72	50	e31	18	30	161	500	715	50	40	79
6	100	62	44	32	19	27	151	437	599	51	35	96
7	95	63	39	26	e15	26	137	390	e517	50	33	108
8	95	70	33	24	17	29	123	358	e442	48	33	99
9	96	104	34	20	22	35	131	329	e422	42	38	150
10	90	110	27	21	e17	42	167	289	404	38	41	926
11	86	87	30	e21	e18	53	237	274	380	34	40	517
12	81	67	34	e20	e22	72	306	301	344	31	39	328
13	76	59	30	e17	30	124	323	382	310	32	43	259
14	71	65	34	19	34	191	410	428	285	32	40	210
15	67	62	36	22	34	232	521	574	255	30	36	178
16	64	53	35	e17	36	303	465	662	236	29	35	158
17	61	47	39	e16	34	335	439	764	225	32	38	141
18	60	55	35	e17	35	236	447	943	212	28	33	126
19	57	49	28	20	35	178	391	892	222	29	31	116
20	56	50	22	21	29	162	336	895	286	29	35	105
21	54	56	32	21	26	175	324	885	232	35	35	98
22	52	60	27	21	24	205	346	988	195	34	34	93
23	56	65	32	21	22	229	358	1,150	175	34	39	85
24	68	67	33	21	21	310	325	1,180	154	34	59	77
25	70	65	34	21	28	303	339	1,120	139	35	51	70
26	66	58	34	20	30	254	437	e1,090	125	34	56	67
27	85	54	31	19	31	250	569	1,140	111	52	60	70
28	84	50	31	19	32	191	647	1,250	96	55	62	68
29	80	48	38	20	---	156	659	1,310	84	66	64	65
30	81	52	e33	20	---	e149	642	1,190	74	67	68	63
31	76	---	e30	19	---	e156	---	1,180	---	61	96	---
TOTAL	2,418	1,947	1,120	677	720	4,564	10,177	23,177	11,048	1,319	1,408	4,633
MEAN	78.0	64.9	36.1	21.8	25.7	147	339	748	368	42.5	45.4	154
MAX	115	110	56	32	36	335	659	1,310	1,100	67	96	926
MIN	52	47	22	16	15	26	123	274	74	28	31	63
AC-FT	4,800	3,860	2,220	1,340	1,430	9,050	20,190	45,970	21,910	2,620	2,790	9,190
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1963 - 2003, BY WATER YEAR (WY)
MEAN	172	126	89.2	73.7	90.7	315	851	1,267	1,004	329	221	210
MAX	618	517	257	153	244	895	2,126	2,926	2,526	1,133	1,014	943
(WY)	(1973)	(1987)	(1987)	(1987)	(1986)	(1995)	(1979)	(1979)	(1979)	(1975)	(1999)	(1970)
MIN	51.2	48.4	31.2	21.8	25.7	47.4	126	91.7	24.8	12.7	15.2	35.3
(WY)	(1979)	(1968)	(1990)	(2003)	(2003)	(1964)	(1977)	(2002)	(2002)	(2002)	(2002)	(1978)

SUMMARY STATISTICS	FOR 2002 CALENDAR YEAR	FOR 2003 WATER YEAR	WATER YEARS 1963 - 2003
ANNUAL TOTAL	19,973.0	63,208
ANNUAL MEAN	54.7	173	396
HIGHEST ANNUAL MEAN			822 1979
LOWEST ANNUAL MEAN			53.5 2002
HIGHEST DAILY MEAN	307 Sep 12	1,310 May 29	5,360 Sep 6, 1970
LOWEST DAILY MEAN	3.9 Aug 26	e15 Feb 7	a3.9 Aug 26, 2002
ANNUAL SEVEN-DAY MINIMUM	4.3 Aug 26	18 Feb 5	4.3 Aug 26, 2002
MAXIMUM PEAK FLOW		1,440 May 29	b8,370 Sep 6, 1970
MAXIMUM PEAK STAGE		3.29 May 29	c6.38 Sep 6, 1970
ANNUAL RUNOFF (AC-FT)	39,620	125,400	287,100
10 PERCENT EXCEEDS	108	479	1,170
50 PERCENT EXCEEDS	43	64	145
90 PERCENT EXCEEDS	11	23	52

e Estimated. a Also occurred Aug 28-29, 2002. b From rating curve extended above 4,400 ft3/s, on basis of slope-area measurement of peak flow. c Gage height, 6.38 ft, recorded, 7.55 ft, from floodmarks.