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Water Supply and Utilization Report
North Platte River Basin
Wyoming Area Office

This report concerns the operation of Reclamation facilities in the North Platte River Basin. Reclamation defines a water year as the time period of October 1 through September 30. Water year is abbreviated in this report as W.Yr. Other organizations furnished information for the Water Supply and Utilization Report. Their cooperation is greatly appreciated.

North Platte River Basin Inflow

The May inflows were below average for Seminoe and Pathfinder Reservoirs in the North Platte Basin. The May inflow into Pathfinder Reservoir was the 6th lowest inflow in the last 30 years.

	May Inflow			May Historical Inflow			Accumulated Inflow (October - May)
Reservoir	W.Yr. 2007	30 Yr. Avg.5	% of Avg.	W.Yr. 2006	W.Yr. 2005	W.Yr. 2004	W.Yr. 2007	30 Yr. Avg.5	% of Avg.
Seminoe	182.6	221.6	82	221.0	226.9	76.9	532.0	512.6	104
Pathfinder1, 2	11.8	31.6	37	10.2	25.1	12.1	47.2	90.7	52
Glendo3	66.0	63.8	103	18.3	23.1	4.2	139.4	175.1	80
Guernsey4	9.8	9.8	100	1.7	1.1	0.8	15.3	24.0	64
1 It is assumed that there is no gain between Seminoe and Kortes Dams.
2 River gain between Kortes and Pathfinder Dams.
3 River gain between Pathfinder and Glendo Dams.
4 River gain between Glendo and Guernsey Dams.
5 30 year average. (1977-2006)

North Platte River Basin
Reservoir Inflow
May

North Platte River Basin Outflow

The May outflows were below average for all reservoirs in the North Platte Basin.

	May Outflow			May Historical Outflow			Accumulated Outflow (October - May)
Reservoir	W.Yr. 2007	30 Yr. Avg.2	% of Avg.	W.Yr. 2006	W.Yr. 2005	W.Yr. 2004	W.Yr. 2007	30 Yr. Avg.2	% of Avg.
Seminoe	70.4	94.1	75	168.5	80.7	33	360.7	553.5	65
Kortes	70.4	94.0	75	168.5	80.7	32.9	360.6	553.2	65
Pathfinder	45.6	110.1	41	167.1	121.5	77.7	329.1	451.2	73
Alcova	35.7	98.4	36	154.7	112.0	63.4	315.9	437.2	72
Gray Reef	35.9	98.2	37	154.8	111.9	63.1	315.8	437.0	72
Glendo1	38.5	122.9	31	164.8	38.8	25.4	72.6	219.3	33
Guernsey	44.1	127.7	35	162.2	33.5	18.5	62.5	215.3	29
1 In 1993 an outlet was constructed at Glendo Dam which is used to provide a flow of approximately 25 cubic feet per second.
2 30 year average (1977-2006).

North Platte River Basin
Reservoir Outflow
May

North Platte River Basin Reservoir Storage

The May storage for the major reservoirs; Seminoe, Pathfinder and Guernsey was below average. The Pathfinder Reservoir storage was the 3rd lowest May storage in the last 30 years.

Reservoir	Total Storage End of May			End of May Historical Storage			Total Conservation Storage Capacity	Percent of Capacity
	W.Yr. 2007	30 Yr. Avg.1	% of Avg.	W.Yr. 2006	W.Yr. 2005	W.Yr. 2004
Seminoe	430.3	607.8	71	460.2	487.7	363.0	1017.3	42
Kortes	4.7	4.7	100	4.7	4.7	4.4	4.7	100
Pathfinder	274.1	670.0	41	301.3	210.3	298.6	1016.5	27
Alcova	180.8	179.4	101	179.6	181.2	179.4	184.4	98
Gray Reef	1.5	1.4	107	1.3	1.6	1.5	1.8	83
Glendo	509.6	481.8	106	423.3	459.6	418.5	517.5	98
Guernsey	27.5	35.2	78	27.8	28.6	28.7	45.6	60
Total	1428.5	1980.3	72	1398.2	1373.7	1294.1	2787.8	51
1 Average is based on the 1977-2006 period.

North Platte River Basin
Resrvoir Storage
End of May

North Platte River Basin Reservoir Storage Ownership

North Platte ownerships were above average. The other ownerships were below average. Kendrick ownership was the 2nd lowest May ownership in the last 30 years. Glendo ownership was the 3rd lowest May ownership in the last 30 years.

Ownership	Ownership of water End of May			End of May Historical Ownership			Total Storage Capacity	Percent of Capacity
	W.Yr. 2007	30 Yr. Avg.5	% of Avg.	W.Yr. 2006	W.Yr. 2005	W.Yr. 2004
Kendrick	422.8	947.8	45	516.3	621.1	720.0	1201.7	35
North Platte1	916.6	820.6	112	823.5	677.0	455.8	1062.1	86
Glendo	76.7	157.2	49	49.7	69.1	96.2	183.2	42
Inland Lakes2	0.0	1.7	0	0.0	0.0	10.0	46.0	0
Cheyenne3	1.6	3.66	44	0.4	1.4	2.7	10.0	16
PacifiCorp4	0.3	1.6	19	2.0	2.0	2.0	2.0	15
WWDC8	4.8	N/A	N/A	5.1	2.4	2.4	N/A	N/A
Other7	6.0	41.8	14	1.5	0.6	4.8	N/A	N/A
1 This includes North Platte Guernsey and North Platte Pathfinder.
2 Water stored temporarily in mainstem facilities for later transfer to the Inland Lakes. This table does not reflect that water currently stored in the Inland Lakes.
3 The City of Cheyenne has a storage contract to store water in Seminoe Reservoir by exchange of Upper North Platte Basin water through a system of trans-basin diversions.
4 Pacific Power has a storage contract to store water in Glendo Reservoir for Dave Johnston Powerplant.
5 Average is based on the 1977-2006 period.
6 Average is based on the 1982-2006 period.
7 Water which is captured in the re-regulation space of Glendo in addition to storage rights, operational water account, and replacement of evaporation losses is labeled as "Re-regulation of Natural Flow" per Wyoming Board of Control Order Docket Number I-2000-3-8 in water Division Number One. In accordance with 2007 Natural Flow and Ownership Procedures, the operational account may contain up to 15,000 acre-feet. On May 31, 2007, the Operational account contained 5,996 Acre-feet and Re-Regulation space contained 31 acre-feet.
8 Wyoming Water Development Commission contracted a portion of Glendo Reservoir re-regulation space for storage of non-project water in 2007.

North Platte River Basin
Ownership of Water
End of May

Inland Lakes Reservoir Storage

Reservoir	Total Storage End of May	30 Year Average5	Percent of Average	Total Storage Capacity
Lake Alice	4,745	5,100	93	11,0341
Little Lake Alice	212	3106	68	1,1662
Lake Winters Creek	1,025	8926	115	1,7463
Lake Minatare	39,369	43,800	90	58,7954
1 At Elevation 4182.0
2 At Elevation 4139.0
3 At Elevation 4125.0
4 At Elevation 4125.0
5 30 year average. (1977-2006)
6 16 year average. (1991-2006)

North Platte River Basin Gross Generation

Power generation was below average for all powerplants in the North Platte Basin.

	May Gross Generation			May Historical Generation			Accumulated Gross Gen. (October - May)
Powerplant	W.Yr. 2007	30 Yr. Avg.2	% of Avg.	W.Yr. 2006	W.Yr. 2005	W.Yr. 2004	W.Yr. 2007	30 Yr. Avg.2	% of Avg.
Seminoe	9.6	13.0	74	24.7	11.9	3.9	41.2	82.8	50
Kortes	11.4	13.4	85	29.2	13.5	5.5	51.3	90.1	57
Fremont Canyon1	9.9	26.3	38	39.3	28.4	19.2	61.1	115.8	53
Alcova	4.0	12.7	31	21.6	14.9	8.7	33.8	55.1	61
Glendo	3.5	12.4	28	17.5	3.6	2.3	3.4	20.6	17
Guernsey	2.8	3.2	88	4.2	2.1	1.1	1.7	6.4	27
1 The powerplant for Pathfinder Dam is Fremont Canyon.
2 Average is based on the 1977-2006 period.

North Platte River Basin
Gross Generation
May

North Platte Estimated April-July Runoff

Basin	June 1, 2007 Estimated April-July Runoff with actual April and May			30 Yr. April-July Runoff Avg.2	Most Probable % of Avg.	Comparative Actual April - July Runoff
	Reasonable Maximum1	Expected	Reasonable Minimum1			W.Yr. 2006	W.Yr. 2005	W.Yr. 2004	W.Yr. 2003
Seminoe Reservoir	495	3953	345	700	56	546	733	277	530
Sweetwater River Above Pathfinder Reservoir	30	254	22	62	40	32	66	34	17
Alcova to Glendo	110	1005	98.5	121	83	45	39	34	93
1 The probability is estimated to be 9 chances in 10 that the actual volume will fall between the reasonable minimum and reasonable maximum.
2 Average is based on the 1977-2006 period.
3 The actual April-May inflow into Seminoe Reservoir was 273,000 AF.
4 The actual April-May inflow from Sweetwater River was 20,000 AF.
5 The actual April-May gain between Alcova and Glendo Reservoirs was 96,000 AF.