|  Nuts and Bolts
Definitions
Equivalent Unit (EU): A unit of water use equal to one single-family residence. Based on current water system characteristics of permanent population and the commercial and part-time resident customers served by PAWSD, there are approximately 1.5 permanent residents per EU. EUs are the basis on which the water demand of all water users - commercial, residential and industrial - is defined. Also known in the water industry as Single Family Equivalent.
Acre-Foot (AF): A volume of water equal to one foot in depth covering an area of one acre equal to 43,560 cubic feet or 325,851 gallons.
Cubic Feet per Second (cfs): A rate of flow of water passing a given point, amounting to a volume of one cubic foot for each second of time. Equal to 7.48 gallons per second, 448.8 gallons per minute, or 1.984 acre-feet per day.
Water Demand Projections
The County and Town share an economic development philosophy which is to cultivate and nurture a vibrant community. This by definition requires continued growth of residents, businesses, second home owners and tourists.
A plan for any new reservoir is always based upon projections of future demand. In order to model the continued growth anticipated for a vibrant community, average growth rates for residents (1985-2005, using most recent Census data available) were projected as continuing. Since 1985 that twenty year average growth rate was 6.4%, and the growth rate in EUs within the PAWSD service area since 1995 was 7.1%.
 For the next thirty-five years (2008-2043), the growth rate has been conservatively projected to allow for multi-year fluctuations in the economy. The growth rate has been projected to continue at 7.1% until 2010, 4% from 2010 to 2025, and 3% from 2025 to 2040.
In addition to population statistics, historical water use was also used in making water demand projections. The historical average yearly water use (1995-2006) was 300 gallons per EU (200 gallons per person) per day, spiking to as high as 593 gallons per EU (395 gallons per person) per day. Although presented as a “per person” figure, this demand includes water used by commercial businesses and tourists as well as raw (untreated) water use such as that used for irrigation by the golf course.
Applying historical water demand to projected growth, the residential population in 2040 served by PAWSD would be 34,511 (assuming current service area of 75% of total population) and EUs served would be 23,007.
What does this mean in terms of water demand and storage?
Again, using the historical water use of 200 gallons per person per day, the total 2040 demand, on average, would be 6,902,200 gallons per day, or 2,519,303,000 gallons per year, or 7,731 acre-feet per year.
This 7,731 acre-feet represents the projected demand of PAWSD customers for raw and treated water, including the demand of those residents living outside the PAWSD boundaries who utilize the fill stations. It does not include the total demand of residents living outside the PAWSD service area but within the San Juan Water Conservancy District boundaries who also depend upon raw water. 7,731 acre-feet also does not include a one-year safety supply.
Including the total demand of Conservancy District residents and a one-year safety supply margin, the total annual storage requirement in 2040 will be approximately 16,500 acre-feet of which PAWSD has only about 4,000 acre-feet presently. This is the minimum storage requirement in 2040. If growth slows this amount will be adequate. If growth continues, on average, at the rate it has for the last 20 years, this will not be adequate.
Studies
The studies to be conducted as part of this Dry Gulch project include:
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Projected costs of the reservoir to be constructed in one or two stages
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Evaluation of the capacity of the pumping plant on the San Juan River to fill Dry Gulch Reservoir
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Cultural and environmental studies, particularly in-stream river flow modeling and endangered species
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Other pre-construction technical studies, such as engineering, financial, legal and other services
Click here for studies that have been completed to date.
Design
In June 2008, the Board approved awarding a contract to MWH Americas, Inc. for the preliminary and final engineering of the new San Juan River diversion, pump station and pipeline and the Dry Gulch Reservoir dam.
Briliam Engineering is designing the new Dry Gulch Water Treatment Plant.
Davis Engineering Services is doing the survey work and will design the distribution system.
Steve Harris of Harris Water Engineering, Inc. is the Project Coordinator.
The Project Team of engineers and PAWSD staff held a project kick-off meeting on August 25, 2008 with another to follow on October 20, 2008.
Land Acquisition
PAWSD, together with the San Juan Water Conservancy District, recently purchased 661 acres of property for the Dry Gulch Reservoir at a cost of approximately $9.8 million. This property is necessary no matter what size a reservoir is ultimately constructed, from a minimum of 12,500 acre feet to a maximum capacity of 35,000 acre feet. A portion of the property will also be used for the new Dry Gulch treatment plant and pump station from the San Juan River.
Acquisition of approximately 140 acres of additional private land are currently under negotiations.
In 2007, the Conservancy District received a grant from State SB 179 funds of $1 million for the property purchase. The remaining costs of acquiring the private property shall be funded through a low-interest loan from the Colorado Water Conservation Board.
Simultaneously, PAWSD and the Conservancy District are pursuing a Forest Service Special Use permit and/or land exchange for the remainder of the property required. This land is also needed regardless of the reservoir size. Click here for Dry Gulch area map .
Permitting
It will take approximately 12 years to obtain all necessary permits for this project.
Permits that will be required for this project include:
• US Corps of Engineers 404 permit
• US Forest Service Special Use permit
• CDOT highway access permit
• Colorado Division of Water Resources approval of dam designs
• Colorado Division of Wildlife review of habitat evaluations
• US Fish and Wildlife Service Endangered Species Section 7 Consultation
The Forest Service Special Use permit application is currently in process.
 Further questions? Click here!
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