FLOOD07275

• County: Costilla
• Community: Costilla County
• Stream Name: Trinchera Creek, Costilla Creek
• Basin: Rio Grande
• Title: Floodplain Information Report
• Date: 3/1/1994
• Prepared For: Costilla County
• Prepared By: CWCB
• Contract/PO #: &&
• Floodplain - Doc Type: Floodplain Report/Masterplan

2.2 Human Settl~ment

TABLE 1, Stream Reaches

Within Costilla County thete are two incorporated
municipalities. the Towns of San Luis and Blanca, as well as
numerous unincorporated settlements. San Luis is the oldest
town in Colorado. havin9 been incorporated in 1851. Tt,e whole
acea was settled as part of the northward expansion by SpaniSh
settlecs from the Santa Fe/Taos area of what is now northern
New Mexico. They were the first white settlers in the area.
Much evidence of the area's Spanish heritage still remains.

Stream
Nam~

Rio Grande

Rio Grande

According to the 1980 U.S. Census. the total population Of
Costilla County was 3,071. In May, 1988 the Colorado
Department of Local Affairs estimated the county's 1987
population at 3,403. The 1980 Census population for the Town
of Blanca was 252. and for the Town Of San Luis it was 842.
State estimates tor 1987 population for the two towns were 289
and 954. respectively.

Trinchera Creek Basin

Trinchera Creek

'j

2.3 Study Reaches

North Branch of
Tcinchera Creek
South Branch of
Trinchera Creek
Sanqre de Cristo
Creek
Ute Creek.

In addition to examining the Rio Grande throuqh Costilla
County, this report examines all three major streams that are
tributary to the Rio Grande (Trinchera Creek. Culebra Creek.,
and Costilla Creek). and their sUbtributaries, from the Sangre
de Cristo Mountains downstream to their confluences with the
Rio Grande (or to the state line in the case of Costilla
Creek). SUbtributaries were studied where existing or
projected population concentr..tions or development activity
warranted delineation. While this study was bein\l prepared.
one are.. of particular interest was the site of tile proposed
gold mininq and millinq project by Battle Mountain Corporation.
about 3 miles east of San Luis in the Rito Seco basin.
Specific stream reaches. with ..ppcoltimate lenqths. are listed
in Table 1.

Wagon Creek

Malo Veg", Creek

,
r'
I
j,
I
I

Placer Creek

Unnamed. Tributary
to TClnchera Creek
Below Smith Res.
Northern Branch to
Unnam~d Tributary
to Trlnchera Creek
Southern Branch to
Unnamed Tributary
to Trinchera Creek
Ojito Creek

2.4 Rio Grande a",sin

~he Rio Grande has its headwaters in the San Juan Mountains
of Hinsdale, Mineral, dnd San Juan Counties. ~levations in the
western headwaters ranqe as high as 13,895 feet. (The hiqhest
elevation in the entire Rio Grande basin is actually in
Costilla County. at 14.345 feet.) The rivl,!r then flows
southeasterly into Rio Grande County and then Alamosa County,
where it turns to the south. It enters Costilla County at an
elevation of about 7.520 feet, forming thO! boundary betw....n
Costilla and Conejos Counties. It leaves Colorado at "0
<elevation of "bout 7.475 teet. <::ontinuinq throuqh Albuquer<:lue

-,-

pescription

Fro~ ~orthern Coun~y
Llmlt to State Line

Upstream 9f Mountain Home
Reservo:tr
Upstream of Smith Reservoir
From Outlet of Smith
Reserv9ir to Confluence
with RIO Grande

Upstream of Confluence
Rio Grande
Upstream of Confluence
Rio Grande
Upstream of Smith Reservoir

with

with

Upstream of Confluence with
Sangre de Cristo Creek
Upstream of Confluence with
S",ngre de Cristo Creek
Upstream of Confluence with
Sangre de Cristo Creek.
Upstream of Confluence with
Sangre de Cristo Creek
Upstream of Confluence with
Tcinchera Creek.

Upstream of Confluence with
Trinchera Creek

Upst~eam of Confluence with
Tnnchera Creek

Upstream of Highline Canal

-,-

Stream
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