Bear River Basin Water Plan
Technical Memoranda

SUBJECT:	Appendix J Municipal Water Use - City of Evanston
PREPARED BY:	Bear River Basin Planning Team

Introduction: The City of Evanston is located in Uinta County in the southwest corner of Wyoming. In the past, the city's economy (and population) has been largely driven by natural resource industries, particularly oil and gas production. As a result, the Evanston economy has cycled through boom and bust periods. Evanston's population leveled off during the 1980's and has grown modestly through the 1990's.

Evanston embarked on a massive water supply project in 1988. This project was completed in 1990 and included:

• Expansion of the Sulphur Creek Reservoir to include 12,200 acre feet of storage for Evanston.
• Construction of a new intake on the Bear River including a settling basin, river cut- off wall, and an 8 CFS infiltration gallery
• Construction of a 36-inch steel pipeline from the Bear River intake to Sulphur Creek Reservoir, along with a 30-inch steel pipeline to feed Evanston's treatment plant from the river and/or reservoir.
• Expansion of Evanston's water treatment plant from 4 MGD to 8 MGD

Sulphur Creek Dam

Evanston Intake setlling basin on the Bear River

Following these projects, Evanston no longer relied on their wells to meet normal system demands.

Construction Photo of Evanston's 36-inch steel transmission pipeline at junction of Sulphur Creek pipeline, Bear River pipeline, and treatment plant feed line

Service Area Population: Approximately 12,200. Service connections are as follows:

		Customer Type		Connections

		¾-inch Residential		3060
		1-inch Commercial		111
		1.5-inch Commercial		63
		2-inch Commercial		89
		4-inch Commercial		28
		6-inch Commercial		13
		Senior Discount			418

			    TOTAL		3782 Connections

In order to reduce demands on the water treatment plant, Evanston has recently completed the construction of an 18-inch raw water transmission pipeline for irrigating parks, the Purple Sage Golf Course, school grounds, etc. That pipeline has a design capacity of approximately 7500 GPM. The city also owns and maintains several ground water wells as follows:

							Reported
Well Name				Depth		Capacity 	Quality

Evanston #1 (River Well)		185 ft		600 GPM		High TDS 
Evanston #2 (Front St Well)		 65		370		High TDS
Evanston #3 (Football Field Well)	 76		300		N/A – Irr.
Evanston #5 (Anderson Park well)	623		530		N/A – Irr.
Evanston #7 (Golf Course Well)		600		250		Not in service
Evanston #8 (Amoco Well)		516		530		High TDS
Peart #1 (Carpenter Well)		100		600

			TOTAL				3180 GPM			

Water Treatment: Conventional Water Treatment Plant with 8 MGD design capacity. Historically, the plant has been able to deliver up to 9 MGD during periods of low turbidity.

Finished Water Storage:

	Location		Size (MG)			

	Treatment Plant		3.0   (3 tanks)	
	Twin Ridge		1.0 			
	Aspen Grove		1.08
	Brook Hollow		0.5 
	Red Mountain		0.25

	    		TOTAL	5.83 MG

Monthly Water Rates: $4.40 / month base rate plus $1.48 per 1000 gallons use. Monthly bill for the use of 20,000 gallons = $34.00.

Annual Water Use: (based on 1999 treatment plant meter records)

1,408 MG = 4321.3 AF

Per Capita Use: (average annual gallons per capita per day)

316 GPCPD

Recorded Peak Day Demand: (based on 1999 treatment plant meter records)

July 7, 1999 - 9.5 MGD = 29.16 AFD

Present peak demand is supply limited. It is anticipated that per capita demand will increase with the construction of a treatment plant expansion (currently under design). The city is also in the process of constructing a 9-hole golf course expansion that will increase demands by approximately 1.1 acre-ft per day during the irrigation season (110 acre-ft annually)

Water Supply System Capacity:

Treatment Plant:     9.00 MGD = 27.6 AFD
Wells:     4.58 MGD = 14.0 AFD

Municipal Water Rights:

Surface Water Source		Proof No.		Priority	Appropriation

Bear River (UPRR)		8600			1869		0.60 CFS
Bear River			8606			1875		4.00
Bear River			8608			1875		0.33
Bear River			8610			1875		0.505
Bear River			8705			1893		3.00
Slough of Bear River
     (Dunford Ditch)		8797			1896		0.37
Bear River  (Anderson Ditch)	8934 (Enl)		1901		0.85
Bear River (UPRR)		8728			1902		0.27
Bear River			14607			1911		2.89 (Fish)
Bear River			14608			1911		0.00 (Fish)
Bear River 
     (Rocky Mtn. Ditch)		16326 (Enl)		1914		0.69
Bear River			17075 (Enl)		1915		0.685
Bear River 			21089 (Enl)		1933		0.25
Bear River (winter)		31585			1974		7.55
Reservoir Diversion		35890			1982		0.00
Reservoir			35834 (Enl)		1982		0.00
Reservoir			35889 (Enl)		1988		0.00

			TOTAL SUMMER					11.55 CFS
			TOTAL WINTER					19.10 CFS


					Permit
Well Source		     		Number		Priority       Appropriation

Evanston #1 (River Well)		P425C		1934		 800 GPM	
Evanston #2 (Front St Well)		P426C		1939		 500	
Evanston #3 (Football Field Well)	P120C 		1951		 300
Evanston #5 (Anderson Park well)	P588W		1961		1200
Evanston #7 (Golf Course Well)		P7141W		1970		Not Adjudicated
Evanston #8 (Amoco Well)		P589W		1977		 500
Peart #1 (Carpenter Well)		P410C		1954		1570

						TOTAL			4870 GPM
									 (10.85 CFS)

As indicated above, the City of Evanston is presently in the design phase of an 8 MGD expansion to their water treatment plant. The expanded plant should be on line in 2002. In addition, the city has recently completed construction of an 18-inch raw water line used for irrigation of parks, etc. This line is intended to reduce demands on the water treatment plant, but is not anticipated to impact overall water consumption in the city.

Evanston is also in the process of constructing a 9-hole golf course expansion that will increase demands by approximately 1.1 acre-ft per day during the irrigation season (110 acre-ft annually)

References:

a) Sunrise Engineering, Inc., Evanston Water System Master Plan Level II Study, November 1997

b) Forsgren Perkins / Rollins, Brown & Gunnell, Upper Bear River Drainage Water Resource Investigation, March 1984