ARKANSAS RIVER BASIN

07128500 PURGATOIRE RIVER NEAR LAS ANIMAS, CO

LOCATION.--Lat 38°02'02", long 103°12'00", in NE14SW14 sec.23, T.23 S., R.52 W., Bent County, Hydrologic Unit 11020010, on left bank at downstream side of bridge on State Highway 101, 2.3 mi southeast of courthouse in Las Animas, and 4.5 mi upstream from mouth. Prior to July 17, 2002, at site on right bank.

DRAINAGE AREA.--3,318 mi2, of which 11.8 mi2 is noncontributing.

PERIOD OF RECORD.--May to September 1889, July to October 1909 (gage heights and discharge measurements only), January 1922 to September 1931, July 1948 to current year. Monthly discharge only for some periods, published in WSP 1311. Published as Purgatoire Creek at Las Animas in 1889 and as Purgatory River near Las Animas in 1909. Statistical summary computed for 1978 to current year, subsequent to completion of Trinidad Reservoir. Daily record for water temperature and specific conductance available, December 1985 to September 1996. For a complete listing of historical data available for this site, see http://waterdata.usgs.gov/co/nwis/inventory/?site_no=07128500

REVISED RECORDS.--WSP 1241: 1927(M); WDR CO-01-1: Drainage area.

GAGE.--Water-stage recorder with satellite telemetry. Datum of gage is 3,878.04 ft above NGVD of 1929. See WSP 1731 for history of changes prior to Oct. 1, 1955. Oct. 1, 1955 to July 11, 1966, at datum 6.00 ft higher. Supplementary water-stage recorder at site 1.6 mi downstream at different datum July 12 to Nov. 17, 1966. Nov. 18, 1966 to
May 4, 1982, at datum 3.1 ft higher. May 5, 1982 to July 17, 2002, at site on right bank at same datum.

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. Flows regulated to some extent by Trinidad Lake (station 07124400) about 141 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.--Flood of Oct. 1, 1904, is the greatest since at least 1860, discharge unknown.

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	6.1	1.7	1.3	3.2	3.6	9.4	49	49	7.4	35	1.0	0.20
2	5.7	1.6	1.3	e3.2	3.5	7.1	42	42	25	14	1.6	0.19
3	5.0	1.4	1.4	e3.2	3.8	6.5	35	35	13	8.6	1.7	0.16
4	4.2	1.3	2.0	4.2	3.5	5.7	45	29	21	4.6	0.35	0.17
5	3.3	1.3	2.2	4.8	3.4	4.7	135	24	16	2.7	47	0.16
6	2.9	1.2	2.1	8.3	3.3	4.5	104	19	14	2.1	e65	0.16
7	2.6	1.2	2.3	8.7	e3.2	4.0	78	17	34	1.9	e15	7.6
8	2.4	1.2	2.5	8.1	e3.0	5.4	69	15	107	1.4	e4.0	1.8
9	2.2	1.3	2.3	6.4	3.1	4.1	53	15	75	1.1	1.5	89
10	2.0	1.3	2.4	e6.2	3.2	5.0	44	11	65	0.90	147	101
11	1.8	1.2	3.0	e6.0	3.5	4.6	38	9.1	59	0.74	154	43
12	1.7	1.3	2.9	e5.6	3.6	4.7	33	8.5	43	0.61	60	26
13	1.5	1.2	2.4	5.4	3.8	4.6	28	9.4	42	0.66	21	14
14	1.4	1.3	2.3	4.8	4.0	3.9	24	7.0	53	1.1	10	8.1
15	1.4	1.3	2.4	4.1	4.1	4.1	21	7.2	42	1.4	5.3	4.6
16	1.3	1.3	2.2	3.5	3.9	13	41	10	23	1.4	1.7	3.6
17	1.3	1.3	2.1	4.2	4.0	4.9	54	9.6	17	0.44	0.62	e2.5
18	1.3	1.2	2.0	3.7	4.1	10	36	4.7	11	0.43	0.32	e2.0
19	1.3	1.2	1.8	3.8	4.7	6.9	36	3.6	166	0.44	0.29	e1.5
20	1.3	1.2	1.7	3.8	4.8	14	40	2.9	72	0.47	0.26	e1.0
21	1.3	1.2	1.8	3.5	4.1	18	36	2.6	50	0.51	0.24	e0.90
22	1.4	1.3	1.8	3.3	3.9	18	30	2.2	31	0.42	0.23	e0.80
23	1.4	1.3	2.1	3.1	4.2	18	24	2.1	29	0.38	0.20	e0.75
24	1.3	1.3	e2.1	3.4	e4.0	17	90	2.2	31	0.37	0.18	e0.60
25	1.3	1.3	e2.0	3.2	3.8	20	298	24	15	0.34	0.16	e0.55
26	1.7	1.3	e2.0	4.2	3.7	64	157	52	14	0.33	0.15	e0.47
27	1.8	1.3	e2.0	7.6	4.8	146	98	31	11	0.34	0.15	e0.54
28	1.4	1.3	3.2	6.9	7.0	162	77	17	7.7	0.35	0.14	e0.68
29	1.4	1.3	3.0	5.5	---	166	67	30	5.4	0.41	0.16	e0.68
30	1.5	1.3	2.8	4.4	---	106	59	18	503	0.35	0.19	e0.61
31	1.4	---	e3.0	4.0	---	75	---	11	---	0.34	0.20	---
TOTAL	66.6	38.9	68.4	150.3	109.6	937.1	1,941	520.1	1,602.5	84.13	539.64	313.32
MEAN	2.15	1.30	2.21	4.85	3.91	30.2	64.7	16.8	53.4	2.71	17.4	10.4
MAX	6.1	1.7	3.2	8.7	7.0	166	298	52	503	35	154	101
MIN	1.3	1.2	1.3	3.1	3.0	3.9	21	2.1	5.4	0.33	0.14	0.16
AC-FT	132	77	136	298	217	1,860	3,850	1,030	3,180	167	1,070	621
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1978 - 2003, BY WATER YEAR (WY)
MEAN	36.4	36.9	29.3	31.4	31.5	42.3	80.1	128	97.8	69.4	123	48.0
MAX	125	88.4	57.5	57.4	61.9	169	418	614	724	263	761	224
(WY)	(1999)	(1999)	(1998)	(1998)	(1998)	(1998)	(1983)	(1987)	(1983)	(1981)	(1981)	(1981)
MIN	1.58	1.30	2.21	4.72	3.91	5.26	3.53	2.15	8.76	2.71	3.76	3.14
(WY)	(1978)	(2003)	(2003)	(1979)	(2003)	(1978)	(1978)	(2002)	(1990)	(2003)	(1980)	(1978)

SUMMARY STATISTICS	FOR 2002 CALENDAR YEAR	FOR 2003 WATER YEAR	WATER YEARS 1978 - 2003
ANNUAL TOTAL	6,717.46	6,371.59
ANNUAL MEAN	18.4	17.5	a63.1
HIGHEST ANNUAL MEAN			166 1983
LOWEST ANNUAL MEAN			17.5 2003
HIGHEST DAILY MEAN	786 Sep 11	503 Jun 30	b3,890 May 3, 1999
LOWEST DAILY MEAN	0.32 Aug 17	0.14 Aug 28	c0.14 Aug 28, 2003
ANNUAL SEVEN-DAY MINIMUM	0.33 Aug 21	0.16 Aug 24	c0.16 Aug 24, 2003
MAXIMUM PEAK FLOW		1,830 Jun 30	d6,680 Jul 5, 1981
MAXIMUM PEAK STAGE		8.46 Jun 30	f10.09 Jul 5, 1981
ANNUAL RUNOFF (AC-FT)	13,320	12,640	45,700
10 PERCENT EXCEEDS	27	49	117
50 PERCENT EXCEEDS	2.7	3.6	29
90 PERCENT EXCEEDS	0.51	0.49	4.0

e Estimated. a Average discharge for 37 years (water years 1923-31, 1949-76), 116 ft3/s; 84,040 acre-ft/yr, prior to completion of Trinidad Reservoir. b Maximum daily discharge for period of record, 46,300 ft3/s, May 20, 1955. c No flow at times in 1924-25, 1927, 1949, and 1974. d From rating curve extended above 4,460 ft3/s; maximum discharge for period of record, 70,000 ft3/s, May 20, 1955, from rating curve extended above 38,000 ft3/s, gage height, 15.00 ft, datum then in use. f Maximum gage height for statistical period, 12.00 ft, May 3, 1999; maximum gage height for period of record, 15.94 ft, Jun 18, 1965, datum then in use.