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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 August inflows were below average for all reservoirs except Glendo Reservoir in the North Platte Basin.

	August Inflow			August Historical Inflow			Accumulated Inflow (October - August)
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	27.1	35.1	77	18.1	28.8	18.5	671.0	924.7	73
Pathfinder1, 2	-3.2	8.6	NA	0.0	-3.0	-1.9	47.4	135.5	35
Glendo3	6.6	-0.6	NA	0.4	5.8	2.9	151.8	194.5	78
Guernsey4	-1.3	1.9	NA	6.0	2.0	4.9	10.4	31.3	33
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
August

North Platte River Basin Outflow

The August outflows for Seminoe and Kortes Reservoirs were above average with the other North Platte Reservoirs near average.

	August Outflow			August Historical Outflow			Accumulated Outflow (October - August)
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	142.8	76.0	188	69.0	103.4	55.5	707.9	872.0	81
Kortes	142.7	76.0	188	68.9	103.4	55.4	707.6	871.8	81
Pathfinder	154.3	155.8	99	128.0	97.9	63.6	751.5	934.9	80
Alcova	144.9	138.1	105	112.5	87.3	44.6	696.1	864.9	80
Gray Reef	145.0	138.1	105	112.5	87.3	44.5	695.9	864.4	81
Glendo1	272.5	293.1	93	263.9	276.4	209.0	860.7	989.1	87
Guernsey	283.2	286.4	99	282.2	265.5	214.9	856.3	996.6	86
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
August

North Platte River Basin Reservoir Storage

The August storage for the major reservoirs; Seminoe, Pathfinder and Glendo was below average. The Pathfinder and Seminoe Reservoir storages were the lowest August storage in the last 30 years.

Reservoir	Total Storage End of August			End of August 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	245.5	678.3	36	280.4	480.2	290.4	1017.3	24
Kortes	4.7	4.6	102	4.7	4.7	4.7	4.7	100
Pathfinder	185.5	524.5	35	209.2	236.5	192.1	1016.5	18
Alcova	180.0	180.0	100	180.1	180.1	181.5	184.4	98
Gray Reef	1.5	1.3	115	1.5	1.6	1.5	1.8	83
Glendo	85.7	141.4	61	110.9	133.4	92.3	517.5	17
Guernsey	14.0	28.5	49	13.6	17.2	6.1	45.6	31
Total	716.9	1558.6	46	1085.2	1053.7	768.6	2787.8	26
1 Average is based on the 1977-2006 period.

North Platte River Basin
Reservoir Storage
End of August

North Platte River Basin Reservoir Storage Ownership

All ownerships except PacifiCorp were below average. Kendrick ownership was the lowest August ownership in the last 30 years. Glendo ownership was the 3rd lowest August ownership in the last 30 years.

Ownership	Ownership of water End of August			End of August 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	368.8	920.4	40	452.0	558.1	656.0	1201.7	31
North Platte1	286.8	484.5	59	312.7	434.5	42.9	1062.1	27
Glendo	57.7	138.1	42	31.4	55.5	65.4	183.2	31
Inland Lakes2	0.0	0.0	0	0.0	0.0	0.0	46.0	0
Cheyenne3	1.3	3.16	42	2.0	3.0	1.6	10.0	13
PacifiCorp4	1.8	1.8	100	2.0	2.0	2.0	2.0	90
WWDC8	0.3	N/A	N/A	0.7	0.5	0.5	N/A	N/A
Other7	0.0	6.9	0	0.0	0.0	0.0	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 August 31, 2007, the Operational account contained 0 Acre-feet and Re-Regulation space contained 0 Acre-feet.
8 Wyoming Water Development Commission contracted a portion of Glendo Reservoir re-regulation space for storage of non-projectwater in 2007.

North Platte River Basin
Ownership of Water
End of August

Inland Lakes Reservoir Storage

Reservoir	Total Storage End of August	30 Year Average5	Percent of Average	Total Storage Capacity
Lake Alice	2,600	3,100	84	11,0341
Little Lake Alice	321	3176	101	1,1662
Lake Winters Creek	628	6016	104	1,7463
Lake Minatare	15,700	16,000	98	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 at or above average for all powerplants except for Glendo powerplant in the North Platte Basin.

	August Gross Generation			August Historical Generation			Accumulated Gross Gen. (October - August)
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	18.6	11.5	162	8.8	15.1	6.9	89.4	125.3	71
Kortes	24.6	12.4	198	11.8	16.7	8.3	111.1	133.2	83
Fremont Canyon1	35.2	33.2	106	29.5	22.6	14.9	157.6	216.2	73
Alcova	20.2	18.0	112	15.5	11.9	5.4	86.5	107.5	80
Glendo	14.4	17.0	85	15.7	18.3	11.2	55.3	72.6	76
Guernsey	4.4	4.1	107	4.5	4.3	3.5	12.2	16.1	76
1 The powerplant for Pathfinder Dam is Fremont Canyon.
2 Average is based on the 1977-2006 period.

North Platte River Basin
Gross Generation
August

North Platte Estimated April-July Runoff

Basin	July 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-June inflow into Seminoe Reservoir was 273,000 AF.
4 The actual April-June inflow from Sweetwater River was 20,000 AF.
5 The actual April-June gain between Alcova and Glendo Reservoirs was 96,000 AF.