ARKANSAS RIVER BASIN

07126300 PURGATOIRE RIVER NEAR THATCHER, CO

LOCATION.--Lat 37°21'23", long 103°53'59", in NW14SW14 sec.10, T.31 S., R.58 W., Las Animas County, Hydrologic Unit 11020010, on right bank 250 ft downstream from county road bridge at gas line crossing, 1.2 mi downstream from Van Bremer Arroyo, and 18 mi southeast of Thatcher.

DRAINAGE AREA.--1,791 mi2, of which 11.8 mi2 is noncontributing.

WATER-DISCHARGE RECORDS

PERIOD OF RECORD.--July 1966 to current year. Statistical summary computed for 1976 to current year, subsequent to completion of Trinidad Reservoir. Daily records of specific conductance and water temperature available, December 1982 to April 1998. Daily records of suspended-sediment discharge available, May 1983 to November 1983, March 1984 to September 1992. For a complete listing of historical data available for this site, see http://waterdata.usgs.gov/co/nwis/inventory/?site_no=07126300

REVISED RECORDS.--WDR CO-01-1: Drainage area.

GAGE.--Water-stage recorder with satellite telemetry and crest-stage gages. Elevation of gage is 4,790 ft above NGVD of 1929, from topographic map.

REMARKS.--Records good except for estimated daily discharges, which are poor. Natural flow of stream affected by storage reservoirs, diversions for irrigation and municipal use, ground-water withdrawals, return flows from irrigated areas, and flows from sewage-treatment plants. Peak flows regulated to some extent by Trinidad Lake (station 07124400) 52 mi upstream since January 1975. 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.--Floods of July 22, 1954 and May 19, 1955, reached stages of 26.7 and 25.2 ft, respectively, from floodmarks, discharges unknown. Flood of June 18, 1965, reached a stage of 23.5 ft, from floodmarks, discharge, 47,700 ft3/s.

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	1.00	e1.5	4.7	e9.2	6.9	e11	32	18	61	20	2.2	19
2	0.83	e1.6	4.7	e9.3	5.9	e11	63	12	18	12	1.2	22
3	0.75	e1.7	5.4	9.5	5.8	e12	172	12	12	10	0.74	11
4	0.62	e1.9	6.7	9.7	5.4	12	141	9.6	23	4.6	1.6	9.9
5	0.55	2.3	7.0	10	5.2	12	76	8.1	64	2.3	20	39
6	0.46	2.4	13	11	5.7	11	53	7.1	196	1.2	3.3	143
7	0.41	2.2	8.9	11	5.8	11	41	6.9	90	0.63	21	240
8	0.39	2.3	6.8	9.5	5.6	10	35	6.6	71	0.33	35	166
9	0.34	2.5	6.7	10	6.7	9.5	30	6.1	70	0.05	187	44
10	0.32	2.9	6.8	9.8	7.1	9.3	24	5.8	64	0.00	140	19
11	0.28	3.2	6.9	9.0	8.4	8.7	20	5.2	70	0.00	11	13
12	0.25	3.2	6.9	8.3	9.4	8.5	19	4.5	68	0.00	3.9	7.7
13	0.24	2.9	6.8	7.8	11	8.4	39	3.9	31	0.00	1.7	8.0
14	0.22	2.8	6.3	7.9	12	8.0	47	3.5	16	0.00	0.78	27
15	0.23	3.2	e6.6	8.2	12	7.4	34	4.1	11	0.00	0.37	20
16	0.25	5.7	e6.6	8.1	12	17	35	4.7	7.7	0.00	0.12	14
17	0.27	5.5	e6.8	8.2	13	9.6	32	4.4	7.8	0.00	0.00	7.7
18	0.30	5.7	e6.8	7.2	12	7.5	21	4.2	142	0.00	0.00	5.0
19	0.29	5.5	e6.8	6.9	12	11	17	3.9	45	0.00	12	3.7
20	0.30	5.2	e6.7	6.9	12	19	20	2.9	36	0.00	6.2	2.4
21	0.30	5.4	e6.6	e7.4	13	22	38	2.4	35	0.00	0.98	1.6
22	0.30	5.2	e6.8	e7.8	12	32	111	2.0	27	0.00	0.31	2.3
23	0.36	4.7	e6.8	e8.0	11	38	313	1.8	28	0.00	0.29	3.1
24	0.40	4.6	e7.0	e8.6	10	93	297	3.6	14	24	0.13	4.9
25	0.39	4.7	e7.0	9.4	e10	192	127	44	15	10	0.00	5.0
26	0.38	4.4	7.0	9.5	e11	168	80	45	13	7.5	0.00	2.7
27	0.52	4.7	7.1	9.5	12	206	66	14	8.6	6.0	0.00	1.5
28	0.60	5.1	7.2	9.6	10	115	58	7.6	5.1	36	0.00	7.0
29	0.51	5.2	8.1	9.6	---	61	42	5.8	3.1	23	0.00	20
30	e1.0	4.9	9.1	9.3	---	41	27	4.3	3.6	13	0.14	11
31	e1.3	---	9.2	8.3	---	31	---	48	---	4.5	33	---
TOTAL	14.36	113.1	219.8	274.5	262.9	1,212.9	2,110	312.0	1,255.9	175.11	482.96	880.5
MEAN	0.46	3.77	7.09	8.85	9.39	39.1	70.3	10.1	41.9	5.65	15.6	29.4
MAX	1.3	5.7	13	11	13	206	313	48	196	36	187	240
MIN	0.22	1.5	4.7	6.9	5.2	7.4	17	1.8	3.1	0.00	0.00	1.5
AC-FT	28	224	436	544	521	2,410	4,190	619	2,490	347	958	1,750
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1976 - 2003, BY WATER YEAR (WY)
MEAN	32.8	31.3	28.0	27.3	29.1	36.8	83.4	125	90.0	81.9	129	58.2
MAX	84.0	66.4	44.3	43.2	53.3	143	467	592	764	547	910	302
(WY)	(1986)	(1999)	(1987)	(1988)	(1987)	(1998)	(1983)	(1987)	(1983)	(1981)	(1981)	(1981)
MIN	0.46	3.71	7.09	8.85	9.39	5.97	1.38	1.45	6.69	5.65	0.012	0.64
(WY)	(2003)	(1979)	(2003)	(2003)	(2003)	(1977)	(1978)	(2002)	(1976)	(2003)	(2002)	(1978)

SUMMARY STATISTICS	FOR 2002 CALENDAR YEAR	FOR 2003 WATER YEAR	WATER YEARS 1976 - 2003
ANNUAL TOTAL	5,567.03	7,314.03
ANNUAL MEAN	15.3	20.0	a63.0
HIGHEST ANNUAL MEAN			181 1981
LOWEST ANNUAL MEAN			12.3 1976
HIGHEST DAILY MEAN	1,140 Sep 10	313 Apr 23	10,000 Jul 3, 1981
LOWEST DAILY MEAN	0.00 Jun 20	0.00 Jul 10	b0.00 Jun 28, 1976
ANNUAL SEVEN-DAY MINIMUM	0.00 Aug 5	0.00 Jul 10	0.00 Jun 28, 1976
MAXIMUM PEAK FLOW		807 Aug 10	c42,400 Jul 3, 1981
MAXIMUM PEAK STAGE		5.80 Aug 10	22.00 Jul 3, 1981
ANNUAL RUNOFF (AC-FT)	11,040	14,510	45,660
10 PERCENT EXCEEDS	19	45	103
50 PERCENT EXCEEDS	4.9	7.5	29
90 PERCENT EXCEEDS	0.00	0.30	5.3

e Estimated. a Average discharge for 10 years (water years 1967-76), 37.9 ft3/s, 27,460 acre-ft/yr, prior to completion of Trinidad Dam. b No flow at times during many years. c From rating curve extended above 2,020 ft3/s on basis of slope-area measurements of peak flow at gage heights 12.25 ft and 23.50 ft.