Northeast Wyoming River Basins Water Plan
Technical Memoranda

SUBJECT:	Appendix J Storage Operation and Description SPENCER
PREPARED BY:	HKM Engineering Inc.
DATE:	March 2002

KEY STORAGE FACILITIES

Reservoir:	SPENCER (or LAK, ENL OF 1890R & 4917R)
Date:	12 Feb. 2001
Location:	SWNE 6,T44N,R60W
Owner:	TRUE RANCHES, INC.
Year of Construction:	1910
Enlargement History:	1940, 1953
Total Storage:	2,847 acre-feet
Active Storage:	2,162 acre-feet
Dead Storage:	Data not available
Area/Capacity Data:	(Source: Feb. 1941 "Map to Accompany Application for Enlargement of Spencer Reservoir," The Ohio Company, applicant, on file in SEO Safety of Dams office.)
	Contour Area (acres) Capacity (af) 1015 104 467 1010 83 390 1005 73 320 1000 55 207 995 28 108 990 15 62 965 10 33 980 3 TOTAL 104 1587
Dam Construction Type:	Earth Fill
Outlet:	Two 18" x ¼" welded steel pipes, asphalt coated, "placed on six- inch centers," (permit). This could mean the pipes were placed with their walls six inches apart.
Spillway:	100 x 5-foot, rock-lined channel cut in the crest of the dam
End-of-Month Storage Records:	No
Water Rights:	(Source: Tabulation of Adjudicated Surface Water Rights of the State of Wyoming, Water Division Number Two, Oct. 1999)
Reservoir Permit Number Permitted Use Priority Date Volume (af) Headgate Location (S-T-R) Spencer Res 1890R I 07-05-1910 98.28 31-45-060 Enl. Spencer 4917R I 06-18-1938 1489 6-44-060 Enl. Spencer 5410R I 02-12-1941 575 6-44-060
Designated Use:	Irrigation
Associated Irrigation Diversions:	Information not available.
Associated Irrigation Diversions:	(Source: Tabulation of Adjudicated Surface Water Rights of the State of Wyoming, Water Division Number Two, Oct. 1999)
Diversion Permit Priority Date Permitted use Flow (cfs) L A K Power Plant 17853 03-27-1931 Power 12
References:	Map to Accompany Application for Enlargement of Spencer Reservoir, the Ohio Company, Newcastle, Wyoming, 3 Feb. 1941.
	Tabulation of Adjudicated Surface Water Rights of the State of Wyoming, Water Division Two, Oct. 1999.

Spencer Dam cross sections ("Map to Accompany Application for Enlargement of Spencer Reservoir", the Ohio Company, Newcastle, Wyoming, 3 Feb. 1941):

Net evaporative loss for Spencer Reservoir:

Lewis Annual Evaporation	40
Total Storage	2,847

	Jan	Feb	Mar	Apr	May	Jun	Jul	Aug	Sep	Oct	Nov	Dec
Average percent of storage	54.3	58.0	66.5	69.8	76.5	78.1	76.6	74.4	72.2	53.8	53.5	53.7
Generated storage (acre-feet)	1546	1653	1894	1988	2177	2222	2182	2117	2056	1531	1523	1528
Corresponding area (acres)	103.2	105.2	109.8	111.5	115.1	115.9	115.1	113.9	112.8	102.9	102.8	102.9
Calculations:
Monthly Lewis Evap. (inches)	1.08	1	1.56	3.2	4.6	5.24	6.84	6.24	4.6	3.04	1.56	1.04
Monthly Precipitation (inches)	0.25	0.75	0.75	1.75	2.75	2.75	1.75	1.75	1.25	0.75	0.75	0.75
Net Evaporation (inches)	0.83	0.25	0.81	1.45	1.85	2.49	5.09	4.49	3.35	2.29	0.81	0.29	TOTAL
Total Net Evaporation (acre-feet)	7	2	7	13	18	24	49	43	31	20	7	2	224