John Martin Reservoir, CO — storage

Storage now, against this reservoir's own record

39.10 Mm³

Stored, October 2020

51st

Percentile among 44 Octs on record

-64.4%

Against the Oct 1991–2020 average

-55.8%

Change over the 12 months to 2020-10

Storage in October 2020 was around the middle of the Oct record, ranked against 44 other Octs held for this reservoir.

Storage, 1977–2020

Monthly mean storage

517 monthly values, 1977 to 2020

Monthly means of the publisher's daily record. Volume, not percentage of capacity: without a capacity whose definition is stated, fullness cannot be computed.

View the data behind this chart

Underlying data
Period	John Martin Reservoir At Caddoa, CO (Mm³)
October 1977	0
November 1977	0
December 1977	0.808
January 1978	2.74
February 1978	5.38
March 1978	7.98
April 1978	3.02
May 1978	0
June 1978	4.56
July 1978	0.736
August 1978	0
September 1978	0
October 1978	0
November 1978	0.584
December 1978	1.53
January 1979	4.17
February 1979	11.5
March 1979	17.5
April 1979	16.2
May 1979	3.84
June 1979	8.12
July 1979	8.42
August 1979	7.63
September 1979	6.15
October 1979	5.12
November 1979	8.99
December 1979	14.6
January 1980	26.0
February 1980	37.5
March 1980	47.2
April 1980	54.5
May 1980	141
June 1980	208
July 1980	162
August 1980	78.4
September 1980	143
October 1980	48.1
November 1980	46.1
December 1980	58.8
January 1981	72.3
February 1981	82.4
March 1981	91.0
April 1981	87.4
May 1981	57.2
June 1981	50.1
July 1981	39.1
August 1981	36.2
September 1981	28.8
October 1981	18.9
November 1981	19.4
December 1981	28.2
January 1982	39.2
February 1982	50.8
March 1982	61.8
April 1982	59.7
May 1982	34.1
June 1982	32.3
July 1982	17.8
August 1982	18.6
September 1982	13.2
October 1982	15.7
November 1982	21.8
December 1982	36.6
January 1983	53.0
February 1983	68.0
March 1983	84.9
April 1983	106
May 1983	121
June 1983	163
July 1983	249
August 1983	181
September 1983	118
October 1983	88.5
November 1983	87.8
December 1983	103
January 1984	120
February 1984	141
March 1984	164
April 1984	189
May 1984	215
June 1984	250
July 1984	245
August 1984	216
September 1984	204
October 1984	206
November 1984	288
December 1984	295
January 1985	318
February 1985	373
March 1985	417
April 1985	413
May 1985	409
June 1985	439
July 1985	406
August 1985	400
September 1985	355
October 1985	343
November 1985	349
December 1985	367
January 1986	392
February 1986	409
March 1986	411
April 1986	349
May 1986	292
June 1986	293
July 1986	272
August 1986	245
September 1986	262
October 1986	263
November 1986	305
December 1986	338
January 1987	372
February 1987	406
March 1987	424
April 1987	436
May 1987	460
June 1987	493
July 1987	424
August 1987	353
September 1987	326
October 1987	312
November 1987	306
December 1987	324
January 1988	343
February 1988	360
March 1988	376
April 1988	372
May 1988	329
June 1988	297
July 1988	220
August 1988	148
September 1988	106
October 1988	99.4
November 1988	102
December 1988	115
January 1989	128
February 1989	141
March 1989	153
April 1989	134
May 1989	106
June 1989	101
July 1989	81.9
August 1989	50.6
September 1989	44.0
October 1989	36.1
November 1989	38.0
December 1989	48.6
January 1990	60.1
February 1990	71.8
March 1990	84.9
April 1990	89.5
May 1990	76.0
June 1990	64.1
July 1990	42.2
August 1990	45.9
September 1990	28.5
October 1990	22.4
November 1990	29.1
December 1990	41.2
January 1991	51.9
February 1991	67.4
March 1991	83.4
April 1991	69.1
May 1991	47.8
June 1991	39.2
July 1991	19.2
August 1991	13.6
September 1991	12.0
October 1991	11.0
November 1991	18.9
December 1991	33.8
January 1992	48.3
February 1992	66.8
March 1992	83.8
April 1992	75.0
May 1992	47.4
June 1992	41.9
July 1992	31.9
August 1992	20.7
September 1992	18.6
October 1992	16.9
November 1992	22.5
December 1992	38.9
January 1993	56.8
February 1993	69.9
March 1993	87.5
April 1993	105
May 1993	91.9
June 1993	115
July 1993	91.2
August 1993	71.0
September 1993	62.7
October 1993	51.3
November 1993	59.1
December 1993	77.9
January 1994	92.3
February 1994	106
March 1994	120
April 1994	114
May 1994	123
June 1994	173
July 1994	135
August 1994	105
September 1994	93.6
October 1994	81.6
November 1994	86.5
December 1994	101
January 1995	115
February 1995	129
March 1995	138
April 1995	129
May 1995	137
June 1995	323
July 1995	445
August 1995	406
September 1995	346
October 1995	324
November 1995	320
December 1995	330
January 1996	346
February 1996	372
March 1996	390
April 1996	348
May 1996	296
June 1996	297
July 1996	284
August 1996	272
September 1996	286
October 1996	287
November 1996	291
December 1996	307
January 1997	322
February 1997	343
March 1997	365
April 1997	331
May 1997	296
June 1997	340
July 1997	351
August 1997	357
September 1997	365
October 1997	352
November 1997	400
December 1997	422
January 1998	426
February 1998	424
March 1998	425
April 1998	426
May 1998	419
June 1998	384
July 1998	322
August 1998	333
September 1998	313
October 1998	301
November 1998	310
December 1998	328
January 1999	350
February 1999	384
March 1999	393
April 1999	394
May 1999	527
June 1999	445
July 1999	411
August 1999	423
September 1999	409
October 1999	402
November 1999	400
December 1999	407
January 2000	419
February 2000	427
March 2000	422
April 2000	412
May 2000	386
June 2000	332
July 2000	255
August 2000	197
September 2000	161
October 2000	140
November 2000	144
December 2000	162
January 2001	178
February 2001	193
March 2001	207
April 2001	213
May 2001	193
June 2001	202
July 2001	149
August 2001	101
September 2001	77.8
October 2001	62.2
November 2001	65.6
December 2001	78.4
January 2002	91.7
February 2002	102
March 2002	111
April 2002	106
May 2002	78.2
June 2002	64.9
July 2002	41.9
August 2002	33.8
September 2002	29.0
October 2002	27.0
November 2002	27.5
December 2002	32.4
January 2003	39.2
February 2003	45.2
March 2003	50.8
April 2003	53.6
May 2003	43.5
June 2003	35.5
July 2003	32.4
August 2003	28.6
September 2003	26.7
October 2003	24.6
November 2003	24.9
December 2003	30.3
January 2004	36.3
February 2004	42.1
March 2004	46.6
April 2004	21.1
May 2004	11.2
June 2004	7.11
July 2004	7.39
August 2004	16.5
September 2004	21.9
October 2004	21.0
November 2004	25.7
December 2004	40.2
January 2005	54.5
February 2005	67.5
March 2005	77.3
April 2005	92.6
May 2005	74.7
June 2005	61.2
July 2005	22.0
August 2005	11.2
September 2005	11.1
October 2005	10.6
November 2005	14.3
December 2005	22.4
January 2006	31.6
February 2006	39.0
March 2006	46.8
April 2006	48.4
May 2006	30.1
June 2006	28.0
July 2006	9.92
August 2006	3.64
September 2006	4.79
October 2006	5.71
November 2006	16.1
December 2006	31.2
January 2007	43.7
February 2007	56.6
March 2007	78.4
April 2007	93.1
May 2007	95.0
June 2007	107
July 2007	77.1
August 2007	47.2
September 2007	38.5
October 2007	26.8
November 2007	31.4
December 2007	44.5
January 2008	57.3
February 2008	69.2
March 2008	79.4
April 2008	75.9
May 2008	63.5
June 2008	59.8
July 2008	33.0
August 2008	30.7
September 2008	36.3
October 2008	37.7
November 2008	47.3
December 2008	61.9
January 2009	74.1
February 2009	84.0
March 2009	94.9
April 2009	101
May 2009	90.2
June 2009	94.4
July 2009	60.9
August 2009	35.9
September 2009	28.6
October 2009	28.3
November 2009	36.9
December 2009	53.0
January 2010	66.3
February 2010	78.2
March 2010	94.5
April 2010	112
May 2010	106
June 2010	97.5
July 2010	54.0
August 2010	37.4
September 2010	29.4
October 2010	33.4
November 2010	36.4
December 2010	46.4
January 2011	57.2
February 2011	66.5
March 2011	76.2
April 2011	72.1
May 2011	48.2
June 2011	43.0
July 2011	24.6
August 2011	13.1
September 2011	10.6
October 2011	12.1
November 2011	15.1
December 2011	23.8
January 2012	34.3
February 2012	44.1
March 2012	52.3
April 2012	56.4
May 2012	38.4
June 2012	31.9
July 2012	28.4
August 2012	24.0
September 2012	20.9
October 2012	20.1
November 2012	20.8
December 2012	25.2
January 2013	29.8
February 2013	34.3
March 2013	37.4
April 2013	38.0
May 2013	32.3
June 2013	22.4
July 2013	20.0
August 2013	26.5
September 2013	26.0
October 2013	23.8
November 2013	22.7
December 2013	29.1
January 2014	37.5
February 2014	46.2
March 2014	53.9
April 2014	55.2
May 2014	40.4
June 2014	32.6
July 2014	26.6
August 2014	23.0
September 2014	10.2
October 2014	8.10
November 2014	12.8
December 2014	23.3
January 2015	32.1
February 2015	41.8
March 2015	56.9
April 2015	62.9
May 2015	103
June 2015	297
July 2015	383
August 2015	330
September 2015	297
October 2015	263
November 2015	259
December 2015	271
January 2016	282
February 2016	291
March 2016	296
April 2016	284
May 2016	268
June 2016	249
July 2016	214
August 2016	165
September 2016	145
October 2016	124
November 2016	120
December 2016	130
January 2017	142
February 2017	153
March 2017	160
April 2017	162
May 2017	215
June 2017	310
July 2017	295
August 2017	309
September 2017	306
October 2017	302
November 2017	311
December 2017	326
January 2018	344
February 2018	374
March 2018	388
April 2018	370
May 2018	342
June 2018	305
July 2018	234
August 2018	204
September 2018	178
October 2018	165
November 2018	168
December 2018	177
January 2019	186
February 2019	197
March 2019	210
April 2019	216
May 2019	198
June 2019	194
July 2019	190
August 2019	151
September 2019	110
October 2019	88.5
November 2019	92.0
December 2019	103
January 2020	113
February 2020	122
March 2020	142
April 2020	144
May 2020	116
June 2020	92.7
July 2020	59.3
August 2020	50.3
September 2020	42.8
October 2020	39.1

The reservoir's year

Seasonal storage profile

Each calendar month's reference average, against the most recent year

1991–2020 average
Most recent 12 months

Twelve separate averages, one per calendar month. A January average describes Januaries only. Months are plotted 1–12.

View the data behind this chart

Underlying data
Period	1991–2020 average (Mm³)	Most recent 12 months (Mm³)
Jan	139	113
Feb	151	122
Mar	162	142
Apr	159	144
May	152	116
Jun	161	92.7
Jul	144	59.3
Aug	128	50.3
Sep	117	42.8
Oct	110	39.1
Nov	117	92.0
Dec	130	103

Rate and persistence

-4.11 Mm³

Mean drawdown per month over 12 months

0 of 24

Months in the last two years below the 20th percentile for their own month

Rates are computed only across an unbroken run of months, so a rate is never divided by a period in which some of the change was not observed. Percentile counts compare each month with the same calendar month in every other year held.

Location

John Martin Reservoir At Caddoa, CO

Gauge location

Where this comes from

517 monthly observations 1977–2020 Mm³

Spatially aggregatedHigh confidenceOctober 2020

Source: USGS — National Water Information System, 07130000. Licence: Open.

Method: Monthly mean of daily reservoir storage published by the USGS in acre-feet and converted to millions of cubic metres. Months with fewer than 20 days of record are not published rather than averaged from a partial month.

Reservoir storage is managed as well as observed: a drawdown may reflect an operating rule, flood-control rule curve or scheduled release rather than a shortage. Compare a month against the same month in other years, and do not read a fall as a supply signal without knowing the operating regime.

Retrieved 25 August 2026.

Monthly mean of daily reservoir storage published by the USGS in acre-feet and converted to millions of cubic metres. Months with fewer than 20 days of record are not published rather than averaged from a partial month.