WSP07440

• File Number: 8443.300
• Description: Narrows Unit - Legislation
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 5/27/1968
• Author: Asst Sec of the Inte
• Title: Narrows Unit Colorado Letter From the Assistant Secretary of the Interior transmitting a report on the Narrows Unit Missouri River Basin Project Colorado Pursuant to Section 9a of the Reclamation Proj
• Water Supply Pro - Doc Type: Report/Study

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to 1~6,370 ac~es of irrigable lend. That total salable water supply does
not rnclude dIvertIble return flows estimated to average 21,300 acre-
feet annually. -
The total estimated J?roject cost of the Narrows unit, prices as of
October. 1965, and estunated annual operation, maintenance, and
replacement expenses have been allocated as follows:

TABLE l.-COST AlLOCA.TIOM SUMMARY

Purpose

Pmjtt\eoo.\

Annual opera~
tion,mainte-
nance,and
replacement

r~1:~y,~~~~~~JJ,i]~tJJ]JJt~~-m:m+~:::~:::::~~~::~~H~~~H~~

Totar~~h____U_________n____________~______. ____ _ ____ ____________uh_

$20,199,400
19,016,100
4,620,000
II, 845, 500
139,000
61,820,000

$22,400
9,100
31,300
1153,700
,
216,500

luttimat'Oandunadi\l'St~t~rtlmeantl'ateofoccurrence.

A segregation of the preceding costs with respect to reimbursa-
bility is contained in table 2. Most of the reilllbursable annual
O.M. & R. for fish-wildlife aud recreation will be the responsibility
of the non-Federal operating entity.

TABLE 2.-REfMBVRSABlE COSTS

Pllrpose

Project
"'''

Annual
operation,
maintenance,
,,'"
replacement

Reimbursable:
~~*:~~J~!~~:::::::::::==============:=::===::::==::::::===:::==::::::::

Nonrtsi~~~~eb~bursabfL-m-m_unu _______________ mun m___u mn

~S~1~;~~~~~{~:;~~~:~~:~i~i~~_=_~~~ ~ ~~~ ~ ~~ ~~ ~~~~ ~~ ~~ ~~ ~~ ~~ ~ ~~~ ~~ ~~-~ ~~~~~~

Total nonreimbursablennn ____n_______n_n_nn_ ____ un ___nun___'n
Grand totaL__________n___nn______u._~___u_n___n_.____u__ _____.__.

$26,199,400
lr'J~:~gg
27,943,600
19,016;100
4,153,600
10,567,700
139,000
33,876,400
61,tzlJ,OOO

$22,400
20,100
144,200
186,700
9,100
11,200
9,500
o
29,800
'l.16,5OO

'd~e~halfofsep.ara~lecosts. Does not include repayabfe interest during construction 01 $24,900 for fish and wildlife
an ....9,500 for recreabon_

. Annual benefits from all functions total $3,675,200 lIS follows:
rrngation, ~1,~31,500; flood control, $961,000; recreation, $790,000;
fish and wildlife, $292,700. BlISed on a 100-year period of analysis
at 3% percent interest, annual benefits will exceed annual costs in
the following ratios: total benefits, 1.62 to 1; direct benefits only,
1.52 to 1.
The existing Lower South Platte Water Conservancy District would
be the contracting entity for payment of annual Federal O.M. & R.
.expenses and repayment of most of the capital costs allocated to
lITIgation. The district will have two bllSic sources of revenue: (a)'

j

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~r~m an ad. valorem _ tax, and (b) from water charges. In addition,
It IS proposed that a charge of $10,000 annually be levied against the
Jackson Lake~Fort Morgan Canal interests for services resulting in
a total estimated O.M. & R. savings of $16,000 annually. This arran(>e-
!'lent would enable a savings of $6,000 annually by those irrigatIOn
mterests. Total net revenues will enable amortization of the irrigation
allocation of $26,199,400 within 50 years without interest.
The non-Federal operating entity would finance or repay the reim-
bursable costs allocated to recreatIOn and fish and wildlife with interest
over a 50-year period.

ACKNOWLEDGMENTS

Summary statements of the Corps of Engineers, National Park
Service, Fish and Wildlife Service, and the Public Health Service
are appended lIS part of this report. The Bureau of Mines prepared a
special report in January 1961 entitled "Mineral Resources at Narrows
Reservoir Site, Morgan County, Colo." That report was revised
in September 1964 and the latter report WllS updated by a mem-
orandum in October 1965. Numerous other Federal, State, and local
agencies have furnished much information and data used in the
studies for the unit. The contributions of each agency have been of
material assistance in the investigations.

Part II-GENERAL DESCRIPTION

The Narrows unit area in northeastern Colorado comprises approxi-
mately the downstream hajj' of the South Platte River Basin in
Colorado.
The upstream hall of the basin originates along the Continental
Divide at elevation approaching 14,000 feet. That area provides most
of the water supply of the basin from native supplies and from trans-
mountain importations. The basin slopes to the east and ,merges into
the Colorado piedmont area in which the Narrows unit is located.
The South Platte watershed through the piedmont section is a
broad rollin~ plain through which the river has formed a wide valley
of flood plams and bench lands OD. river terraces. The bench lands
are situated some 20 to 200 feet higher than the flood plains. The
river has a gradient of 8 to 10 feet per mile. Geologically, the Colorado
piedmont section is classified as late mature or old with outcroppings
of shales and sandstones of the Pierre formation.
The two most important South Platte River tributaries of concern
to the Narrows UnIt are Kiowa and Bijou Creeks. Both tributaries
enter the river from the south. Both tributaries flow through areas
of poorly consolidated sediments and, during periods of high -runoff,
contribute considerable quantities of sediment to the river. Kiowa
Creek flows into the river within the Narrows Reservoir site. Bijou
Creek, however, empties into the river immediately downstres.m from
the Narrows Dam site. Numerous other tributaries, mostly inter-
mittent, enter the South Platte River from both the north and south
in the reach between Narrows Reservoir and the Colorado- N ebrllSka
boundary.