ARKANSAS RIVER BASIN

07097000 ARKANSAS RIVER AT PORTLAND, CO

LOCATION.--Lat 38°23'18", long 105°00'56", in NE14NE14 sec.20, T.19 S., R.68 W., Fremont County, Hydrologic Unit 11020002, on right bank at upstream side of bridge on State Highway 120 at Portland, and 1 mi downstream from Hardscrabble Creek.

DRAINAGE AREA.--4,024 mi2.

WATER-DISCHARGE RECORDS

PERIOD OF RECORD.--May 1939 to September 1952, October 1974 to current year. For a complete listing of historical data available for this site, see
http://waterdata.usgs.gov/co/nwis/inventory/?site_no=07097000

GAGE.--Water-stage recorder with satellite telemetry. Datum of gage is 5,021.59 ft above NGVD of 1929. Prior to Oct. 1, 1974, at site 400 ft downstream at datum 0.03 ft lower.

REMARKS.--Records good except for estimated daily discharges, which are poor. Natural flow of stream affected by storage reservoirs, power developments, transbasin and transmountain diversions, diversions for irrigation and municipal use, ground-water withdrawals, return flows from irrigated areas, and flows from sewage-treatment plants.

COOPERATION.--Records collected and computed by Colorado Division of Water Resources and reviewed by U.S. Geological Survey.

EXTREMES OUTSIDE PERIOD OF RECORD.--Flood of Aug. 21, 1965, reached a discharge of 23,900 ft3/s, from rating curve extended above 7,400 ft3/s on basis of slope-area measurement of peak flow, gage height, 11.85 ft.

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	135	221	237	242	184	217	205	198	3,660	850	590	296
2	169	240	232	227	188	211	244	170	3,740	862	596	255
3	205	232	232	224	193	208	366	156	3,460	806	569	256
4	221	226	234	237	200	191	356	165	2,980	747	548	273
5	222	218	226	250	186	200	373	159	2,560	720	536	269
6	198	217	228	258	186	198	323	155	2,280	719	464	285
7	187	213	229	252	e165	197	311	157	1,850	695	478	279
8	171	228	215	228	e161	197	314	157	1,450	656	523	339
9	173	227	232	212	e150	206	310	142	1,220	667	467	372
10	171	227	231	200	e173	193	304	150	1,360	680	540	354
11	154	228	204	203	e177	194	254	154	1,650	661	581	466
12	135	212	205	209	197	188	251	151	1,770	695	594	470
13	139	207	198	208	209	186	264	144	1,900	669	496	442
14	130	221	214	206	230	189	237	150	2,060	670	372	456
15	119	239	220	203	222	182	221	162	1,930	681	281	421
16	118	227	220	196	206	183	266	245	1,900	655	258	403
17	123	209	214	174	196	211	215	317	2,060	658	236	323
18	134	201	215	169	195	264	179	359	1,870	629	250	277
19	128	208	205	176	213	252	186	526	1,770	610	249	298
20	140	209	e168	183	200	207	189	855	1,790	638	283	325
21	149	204	e177	192	198	213	171	818	1,880	641	276	302
22	149	209	e198	200	198	212	168	648	1,710	656	250	296
23	168	216	e225	192	207	209	164	751	1,680	635	248	298
24	184	224	e230	191	e188	223	190	1,420	1,510	601	351	268
25	199	227	e220	177	e170	237	180	1,540	1,180	600	320	238
26	191	230	e225	173	e198	221	171	1,630	1,000	624	392	223
27	202	216	e215	165	e203	230	171	1,740	918	675	390	210
28	191	206	256	169	210	222	187	2,230	882	810	378	211
29	192	226	279	178	---	209	195	2,690	857	772	367	213
30	206	227	268	184	---	199	254	3,190	855	724	345	200
31	217	---	234	186	---	195	---	3,600	---	582	331	---
TOTAL	5,220	6,595	6,886	6,264	5,403	6,444	7,219	24,929	55,732	21,288	12,559	9,318
MEAN	168	220	222	202	193	208	241	804	1,858	687	405	311
MAX	222	240	279	258	230	264	373	3,600	3,740	862	596	470
MIN	118	201	168	165	150	182	164	142	855	582	236	200
AC-FT	10,350	13,080	13,660	12,420	10,720	12,780	14,320	49,450	110,500	42,220	24,910	18,480
STATISTICS OF MONTHLY MEAN DATA FOR WATER YEARS 1939 - 2003, BY WATER YEAR (WY)
MEAN	384	414	377	358	349	363	487	1,175	2,433	1,531	914	440
MAX	1,083	748	693	626	774	683	1,869	2,680	4,429	4,472	2,380	1,008
(WY)	(1985)	(1985)	(1983)	(1983)	(1985)	(1989)	(1942)	(1984)	(1980)	(1995)	(1984)	(1982)
MIN	136	191	212	199	162	147	135	245	292	201	144	134
(WY)	(1978)	(1978)	(1978)	(1979)	(1978)	(1978)	(1981)	(1977)	(2002)	(2002)	(2002)	(2002)

SUMMARY STATISTICS	FOR 2002 CALENDAR YEAR	FOR 2003 WATER YEAR	WATER YEARS 1939 - 2003
ANNUAL TOTAL	85,141	167,857
ANNUAL MEAN	233	460	775
HIGHEST ANNUAL MEAN			1,387 1995
LOWEST ANNUAL MEAN			264 2002
HIGHEST DAILY MEAN	673 Jul 6	3,740 Jun 2	7,460 Jun 8, 1942
LOWEST DAILY MEAN	91 Sep 18	118 Oct 16	66 Oct 28, 1977
ANNUAL SEVEN-DAY MINIMUM	119 Sep 16	127 Oct 13	76 Oct 24, 1977
MAXIMUM PEAK FLOW		3,820 Jun 2	a21,100 Jun 5, 1949
MAXIMUM PEAK STAGE		5.93 Jun 2	12.18 Jun 5, 1949
ANNUAL RUNOFF (AC-FT)	168,900	332,900	561,300
10 PERCENT EXCEEDS	344	870	1,840
50 PERCENT EXCEEDS	224	227	447
90 PERCENT EXCEEDS	134	169	219

e Estimated. a From rating curve extended above 5,300 ft3/s.