WSP07946

• File Number: 8449
• Description: South Platte Projects - Hardin Dam
• State: CO
• Basin: South Platte
• Date: 12/1/1982
• Author: Dames and Moore
• Title: Hardin Dam
• Water Supply Pro - Doc Type: Publication

the Narrows decree is 180,700 ac-ft per year, while that for the 1981 Hardin
filing is 150,300 ac-ft per year.

The storable flow for the 1981 Hardin Dam filing was subjected to a

reservoir operation study using a matrix of assumed storage values and assumed

demands to estimate the net available water at the Hardin Dam site. The

Narrows decree was similarily evaluated using selected storage values and

demands. It was concluded there was little difference in net yield from that

of the 1981 Hardin filing. The sizing and costing of the project then pro-

ceeded to conclusion utilizing the 1981 Hardin filing.

ANALYSIS OF PROJECT YIELD

The market for water depends on its price. Since price, demand and

project output are all interdependent, it is highly speculative to estimate a

reasonable or optimum allocation of active storage without extensive economic

analyses. Such analyses were beyond the scope of this study. To overcome

this problem it was decided to study and present the results of a range of

assumed active storage volumes and assumed demands. The results of the

operation studies for these assumptions is a graphical relationship between

construction cost, conservation storage volume, reliability and quantity

of reservoir yield.

.,
I
"
I:
J,
I
I
I
,

Cost, capacity, reliability and yield data for conservation pools
ranging in size from 150,000 to 600,000 ac-ft using reservoir operation
studies were developed. Because of the large fixed costs of foundation
preparation and providing surcharge storage, a minimum conservation pool of
200,000 ac-ft was selected. A conservation pool of 600,000 ac-ft was selected
as the upper boundary, because it is the maximum volume which can be stored
without flooding significant development at Greeley during the inflow design
flood. On the basis of these studies a conservation pool of 400,000 ac-ft
with a yield of 100,000 ac-ft per year at 90 percent reliability was selected
for detailed study.

Hi

I
I
I
I

I;