Lower South Platte River Study

• Contractor Name: Colorado Water Conservation Board
• Loan Projects - Doc Type: Feasibility Study

Lower South Platte River Study
Colorado Water Conservation Board
' December 2001
In general, sites with lower ratios of dam volume to potential reservoir storage volume would
' be considered more attractive than those with higher ratios. The dam volume generally is a
good indicator of the total construction cost for a dam project, especially when dam sites are
"off-channel" and have relatively small drainage basins. However, facilities required to fill
the reservoirs will have significant impact on the total cost of each potential storage
alternative. Considerations with respect to reservoir filling facilities are discussed in Section
I 4.2.
4.1.1 Descriptions of the Storage Options
' The paragraphs provide descriptions of the potential storage developments. Cost information
' is presented for each site based on the dam configuration and cost-estimating criteria
provided later in Section 4.1.2. Cost estimates currently exclude land acquisition; however,
arfi i t s in $2
' $500 conti per ngency acre. Cost allownces estimates ae suf for the cient sites to are nclude mantici suma rized ated in Table lancost 4-2, with the cost range details
to
provided for each site in Tables 4-4 to 4-22 at the end of Section 4.
' Previously Identified Sites
i Ovid
Development of the Ovid Reservoir site was proposed in January 2000 by Tuttle-
Applegate, Inc. This proposed reservoir site is located about 12 miles upstream of the
Nebraska State line along the Lower South Platte River and 1 mile west of Ovid,
Colorado. The basin area above the site is privately owned and no relocation of
buildings or roads would be necessary for reservoir construction. The site currently is
under cultivation. The site is not crossed by defined drainages, but does contain
wetlands based on CDOW and USFWS wetlands delineation maps, as well as field
observations. The basin area above the site has a contributing drainage area of 10.2
mil, based on USGS 7.5-minute quadrangle mapping. However, the reservoir would
' be entirely above grade so that the only uncontrolled water reaching the reservoir
would be from precipitation. The reservoir would have a storage capacity of 5,800
acre-feet and a maximum normal pool at Elevation 3550. A smaller reservoir design
was also considered by Tuttle-Applegate but would not be adequate to meet project
needs. The dam would be a zoned embankment with a height of 25 feet and a crest
length of 15,400 feet. Water could be supplied by gravity to the reservoir from the
' Peterson Ditch. Reservoir releases would be made by an outlet ditch to the South
Platte River. The total cost to build the reservoir would be $5,300,000 or$920 per
' acre-foot of storage.
GEI Consultants, Inc. 4-3 01002 Dec 2001 Lower South Platte River Study