USGS
science for a changing world
Sources of water to the Rio Grande Upstream from
San Marcial, New Mexico
By Stephanie J. Moore', Scott K. Anderholm', Tara Williams-Sether', and John M. Stomp
1 U.S. Geological Survey, 2 City of Albuquerque--Water Resources Management
Introduction
The Rio Grande watershed is a
complex hydrologic system that
includes numerous tributaries, inflow
from transmountain diversions,
irrigation diversions, agricultural return
flows, reservoirs, and ground-water
inflows and outflows. Many people
depend on and are affected by the Rio
Grande, which is the largest river of the
surface-water system draining the Rio
Grande watershed. To provide
information to further the
understanding of the Rio Grande
surface-water system, the U.S.
Geological Survey, in cooperation with
the City of Albuquerque, evaluated
streamflow data computed by the U.S.
Geological Survey at 60 streamflow-
gaging stations. This fact sheet
examines the sources of water to the Rio
Grande and the "water balance" of the
Rio Grande surface-water system
upstream from San Marcial, New
Mexico, by comparing the mean annual
discharge (streamflow) at different
stations.
Hydrologic Description of the
Rio Grande Watershed
The study area includes the Rio
Grande watershed in Colorado and New
Mexico upstream from San Marcial,
New Mexico, and covers approximately
27,700 square miles (fig. 1). Altitudes
in the watershed range from greater than
14,000 feet along the northernmost
boundary of the watershed in Colorado
to approximately 4,455 feet at San
Marcial, New Mexico. Average annual
precipitation varies from greater than
50 inches per year along the
northwestern mountainous areas to less
than 6 inches per year south of
Albuquerque, New Mexico (Ellis and
others, 1993). In the mountainous areas,
the majority of annual precipitation
falls as snow during the winter months;
at lower altitudes, the majority of
annual precipitation falls as rain during
late summer and early fall
thunderstorms.
Potential evapotranspiration, which
is approximated by open-water
evaporation, varies from less than 35
inches per year in the mountainous
areas to greater than 70 inches per year
near San Marcial (Ellis and others,
1993). Actual evapotranspiration (the
total water removed from an area by
transpiration from plants and
evaporation from soil, snow, and water
surfaces) is always less than potential
evapotranspiration because it is limited
by available moisture (Linsley and
Franzini, 1972, p. 33).
The numerous tributaries in the Rio
Grande watershed can be classified as
either perennial or ephemeral. Perennial
tributaries flow throughout the year,
whereas ephemeral tributaries are dry
most of the year and flow only in
response to snowmelt or intense
rainfall. The Rio Chama, which is the
largest tributary to the Rio Grande,
enters the Rio Grande upstream from
the streamflow-gaging station Rio
Grande at Otowi Bridge, near San
Ildefonso, New Mexico (fig. 1,
reference no. 39). Transmountain
diversions (imported water from the
Colorado River watershed on the west
side of the Continental Divide is
transferred to the Rio Grande watershed
on the east side of the Continental
MAR 11 2004
- DEPOSITED BY
UNITED STATES OF AMERICA
Divide) affect both the Rio Grande and
the Rio Chama.
Effluent discharge from wastewater-
treatment plants provides inflow to the
Rio Grande surface-water system. The
Albuquerque wastewater-treatment
plant is the largest in the watershed;
daily mean discharge from that plant to
the Rio Grande ranged from about 75 to
100 cubic feet per second (ft's) from
1985 to 1998 (U.S. Army Corps of
Engineers, 2002).
Reservoirs in the Rio Grande
watershed (fig. 1) are generally
operated for water storage, sediment
removal, flood control, or some
combination of these uses. Reservoirs
can alter discharge because the
impounded water can be "lost" by
evaporation or by infiltration (seepage)
to the surrounding ground-water
system. In addition, changes in
reservoir storage can affect mean
annual discharge; however, using a
longer period of record to calculate
mean annual discharge generally
minimizes the effects of changes in
reservoir storage.
Rio Grande below Goose Creek, Colorado.
U.S. Department of the Interior
U.S. Geological Survey
USGS Fact Sheet 110-03
December 2003


EXPLANATION
Reach boundary
Streamflow-gaging station reference number
Station location and mean annual discharge,
in cubic feet per second (see table 1 for period of record)
Mean annual discharge, in cubic feet per second.
Width of band (below) is approximately proportional
to magnitude of discharge
55 180 350
20 95
25 50 MILES
I I
25 50 KILOMETERS
35°
108°
1,700
1,400
,40 1,550
1,000
Rio San Jose
34°
106°
s
O 5 º
*37° 3
132 §
30 HerOn . . . " s
146 Lºſ Reservoir . 21–4 S
3 * 28 Reach 3564
* \, gº" a
3 TO Reservoir *
523 lº %
* Abiquiu 35
33– Reseº 79 8. §
So IS
º, º sº # G
| sº spañola 941 RS
: º *. . 2 3
; tº "... 39 ſ ,
*H º 4% *1,660...} $
º Lake se º CŞ
9: 41 + 42 + 4 & “.
Jemez 1,640 % #
& Reservoi
...” - (2%
* * 47 NA. ºg,
* 7 X ſº #
RoRancho I -
48 Albu(Uerdue
14% º Aº
T T T T ~ T
/ COLORADO MAP
ſ AREA
& - - - --
56 +57+ 58 C.
1,520
SOCOrſo
59 + 6
1,350
San ACàcia
San Marcial
NEW
|
I
|
I
|
I
|
I MEXICO
LOCATION MAP
Figure 1. Mean annual discharge at selected streamflow-gaging stations in the Rio Grande watershed upstream from San Marcial,
New Mexico. Station names shown in table 1.













Table 1. Mean annual discharge at Selected streamflow-gaging stations in the Rio Grande watershed upstream from San Marcial, New Mexico.
[ft/s, cubic feet per second]
Reference — U. S. Geological Survey !. Period of Reach Reference — U. S. Geological Survey !. Period of
number Station discharge record number Station discharge' ºrd" Reach
(fig. 1) number Station name (ſtºls) used (fig. 1) (fig. 1) number Station name (ſtºls) used (fig. 1)
1 08213500 Rio Grande at Thirtymile Bridge, near Creede, Colo. 214 1975-98 1 31 08284.520 Willow Creek below Heron Dam, N. Mex. 134 1975-98 3
2 08214500 North Clear Creek below Continental Reservoir, Colo. 30 1975-98 1 32 08285500 Rio Chama below El Vado Dam, N. Mex. 523, 1975-98 3
3 08216500 Willow Creek at Creede, Colo." 22 1975-82 33 08286500 Rio Chama above Abiquiu Reservoir, N. Mex. 555 1975-98 3
4 08217500 Rio Grande at Wagon Wheel Gap, Colo. 586 1975–98 1 34 08287000 Rio Chama below Abiquiu Dam, N. Mex. 581 1975–98 3
5 08218500 Goose Creek at Wagon Wheel Gap, Colo' 68 1975–91 1 35 08289000 Rio Ojo Caliente at La Madera, N. Mex. 79 1975–98 3
6 08219500 South Fork Rio Grande at South Fork, Colo." 226 1975-95. 1 36 08290000 Rio Chama near Chamita, N. Mex. 649 1975–98 3
7 08220000 Rio Grande near Del Norte, Colo. 909 1975–98 1 37 08291000 Santa Cruz River at Cundiyo, N. Mex. 38 1975–98 3
8 08223000 Rio Grande at Alamosa, Colo." 269 1975-95 2 38 08292000 Santa Clara Creek near Española, N. Mex." 4.2 1985-94 3
9 08236.000 Alamosa River above Terrace Reservoir, Colo' 112 1975–92 2 39 08313000 Rio Grande at Otowi Bridge, near San Ildefonso, N. Mex. 1,660 1975-98 3
10 03238000 La Jara Creek at Gallegos Ranch, near Capulin, Colo' 14 1975–82 2 40 08317200 Santa Fe River above Cochiti Lake, N. Mex. 12 1975–98 4
11 08240000 Rio Grande above mouth of Trinchera Creek, near Lasauses, Colo. 315 1975-98 2 41 08314000 Sili Main Canal (at head) at Cochiti, N. Mex.” 44 1975-98 4
12 08243500 Trinchera Creek below Smith Reservoir, near Blanca, Colo." 9.1 1975-82 2 42 08313500 Cochiti Eastside Main Canal at Cochiti, N. Mex.” 80 1975-98 4
13 08245000 Conejos River below Platoro Reservoir, Colo. 100 1975–98 2 43 08317400 Rio Grande below Cochiti Dam, N. Mex.” 1,510 1975-98 4
14 08246500 Conejos River near Mogote, Colo. 327 1975–98 2 44 08317950 Galisteo Creek below Galisteo Dam, N. Mex. 5.5 1975–98 4
15 08247500 San Antonio River at Ortiz, Colo. 28 1975-98 2 45 08319000 Rio Grande at San Felipe, N. Mex. 1,610 1975-98 4
16 08248000 Los Pinos River near Ortiz, Colo. 123 1975–98 2 46 08324000 Jemez River near Jemez, N. Mex. 91 1975-98 4
17 08248500 San Antonio River at mouth, near Manassa, Colo." 93 1975-82 2 47 08329000 Jemez River below Jemez Canyon Dam, N. Mex. 77 1975-98 4
18 08249000 Conejos River near Lasauses, Colo. 193 1975-98 2 48 08330000 Rio Grande at Albuquerque, N. Mex. 1,480 1975-98 5
19 08251500 Rio Grande near Lobatos, Colo. 528 1975-98 2 49 08331990 Rio Grande Conveyance Channel near Bernardo, N. Mex: 9.8 1975-98 5
20 08255500 Costilla Creek near Costilla, N. Mex. 52 1975-98 3 50 08332010 Rio Grande Floodway near Bernardo, N. Mex. “ 1,320 1975-98 5
21 08263500 Rio Grande near Cerro, N. Mex. 564. 1975-98 3 51 08332050 Bernardo Interior Drain near Bernardo, N. Mex." 68 1975-98 5
22 08266820 Red River below Fish Hatchery, near Questa, N. Mex." 85 1978-98 3 52 08334000 Rio Puerco above Arroyo Chico, near Guadalupe, N. Mex. 15 1975-98 5
23 08267500 Rio Hondo near Valdez, N. Mex. 39 1975–98 3 53 08343000 Rio San Jose at Grants, N. Mex. 0.87 1975-98 5
24 08276300 Rio Pueblo de Taos below Los Cordovas, N. Mex. 81 1975-98 3 54 08343500 Rio San Jose near Grants, N. Mex. 6.3 1975-98 5
25 08276500 Rio Grande below Taos Junction Bridge, near Taos, N. Mex. 850 1975-98 3 55 08353000 Rio Puerco near Bernardo, N. Mex. 32 1975-98 5
26 08279000 Embudo Creek at Dixon, N. Mex. 99 1975-98 3 56 08354500 Socorro Main Canal North at San Acacia, N. Mex.” 123 1975-98 5
27 08279500 Rio Grande at Embudo, N. Mex. 941 1975-98 3 57 08354800 Rio Grande Conveyance Channel at San Acacia, N. Mex: 243 1975-98 5
28 08284.100 Rio Chama near La Puente, N. Mex. 410 1975-98 3 58 0835.4900 Rio Grande Floodway at San Acacia, N. Mexº 1,150 1975-98 5
29 08284.160 Azotea Tunnel at Outlet, near Chama, N. Mex. 132 1975-98 3 59 03358300 Rio Grande Conveyance Channel at San Marcial, N. Mex° 268 1975-98 5
30 08284200 Willow Creek above Heron Reservoir, near Los Ojos, N. Mex. 146 1975-98 3 60 08358.400 Rio Grande Floodway at San Marcial, N. Mex° 1080 1975-98 5
"Period of record used is not equal to 1975-98.
* Missing data for 1993-94 and 1995.
3 Total discharge at Cochiti, N. Mex., is 1,630 ft°/s and includes the Sili Main Canal, Cochiti Eastside Main Canal, and the Rio Grande (conveyance channels not shown on map).
*Total discharge near Bernardo, N. Mex., is 1,400 fês and includes the Rio Grande Conveyance Chanel, Rio Grande Floodway, and Bernardo Interior Drain (conveyance channels not shown on map).
*Total discharge at San Acacia, N. Mex., is 1,520 ft*/s and includes the Socorro Main Canal North, Rio Grande Conveyance Channel, and Rio Grande Floodway (conveyance channels not shown on map).
*Total discharge at San Marcial, N. Mex, is 1,350 ſtº/s and includes the Rio Grande Conveyance Channel and Rio Grande Floodway (conveyance channels not shown on map).
Surface-water use is defined as the
volume of surface water diverted or
withdrawn from a river channel or
source (Wilson and Lucero, 1997, p. 71-
74). After this water has been used, it
may be returned to the river channel (for
example, by return flows from
agricultural areas) or it may leave the
surface-water system (for example, by
evapotranspiration from agricultural
areas). Water not returned to the river
channel is referred to as depletion and
results in a decrease in discharge. As
used herein, surface-water use does not
include evapotranspiration by riparian
vegetation or evaporation from open-
water surfaces.
Water use is affected by many
factors such as population, climate, and
legal constraints. The Rio Grande
Compact appropriates water use in the
Rio Grande watershed. The States of
Colorado, New Mexico, and Texas
agreed upon the Compact for "the
purpose of effecting an equitable
apportionment of water in the Rio
Grande" (Rio Grande Compact
Commission, 2001, p. 18), and surface-
water use in those States is restricted by
Compact delivery obligations.
An acre-foot is the quantity of water
required to cover 1 acre to a depth of 1
foot and is equivalent to 43,560 cubic
feet or 325,851 gallons.
Total surface-water use in 1990 in
the Rio Grande watershed upstream
from San Marcial was approximately
1,570,000 acre-feet (equivalent to a
discharge of 2,163 ft/s for 1 year)
(Richey and Ellis, 1993). The largest
use of surface water was irrigation (99
percent); other categories of surface-
water use include public supply,
commercial, domestic, industrial,
mining, thermoelectric, and livestock.
To evaluate water use in different
parts of the watershed and to examine
possible causes of variations in
discharge throughout the watershed, the
watershed was divided into five reaches
that were based primarily on locations
of gaging stations (fig. 1). Surface-
water use in the five reaches is shown in
figure 2 as a percentage of total surface-
water use in 1990 (1,570,000 acre-feet).
Reach 2 had the largest amount of
surface-water use. Reaches 1 and 4 had
relatively little surface-water use.
Water use in the different reaches varies
because of allocations that are based on
the Rio Grande Compact and locations
of irrigable land.
Sources of Water to the Rio
Grande
Mean annual discharge (the
arithmetic mean of the annual mean
discharge for every year in a given
period) for 60 gaging stations
throughout the Rio Grande watershed
upstream from San Marcial is shown in
figure 1. To eliminate the comparison of
data from periods of varying climatic
conditions, water years 1975-98 were
chosen as a common period of record
(water year is the 12-month period
October 1 through September 30
designated by the calendar year in
which it ends). Twelve gaging stations
did not have data available for the entire
period of record; these exceptions are
noted in table 1. Mean annual discharge
at these gaging stations may represent
different climatic conditions than those
in 1975–98. Each mean annual
Reach 5
(21%)
Reach 4
Reach 3
(15%)
Total surface-water use was 1,570,000 acre-feet per year (Richey and Ellis, 1993).
Reach 1
(less than 1%)
Reach 2
(61%)
Figure 2. Surface-water use, by reach, as a percentage of total surface-water use
in the Rio Grande watershed upstream from San Marcial, New Mexico,
1990. Reach boundaries shown in figure 1.
discharge has some error associated
with it. No attempt has been made to
quantify the error associated with the
mean annual discharge for each gaging
station.
At some locations in the watershed,
particularly in agricultural areas, water
moves downstream in the Rio Grande
and in other channels adjacent to the
Rio Grande such as agricultural canals
or drains. At New Mexico gaging
Stations Rio Chama near Chamita
(reference no. 36), Rio Grande at San
Felipe (reference no. 45), and Rio
Grande at Albuquerque (reference no.
48), discharge is computed only in the
Rio Grande; therefore, discharge
moving downstream through the
surface-water system is greater than
that computed in the Rio Grande. At
New Mexico gaging stations Rio
Grande below Cochiti Dam (reference
no. 43), Rio Grande Floodway near
Bernardo (reference no. 50), Rio
Grande Floodway at San Acacia
(reference no. 58), and Rio Grande
Floodway at San Marcial (reference no.
60), discharge is computed in the Rio
Grande and in other major channels
adjacent to the Rio Grande; at these
locations, the discharge computed in
each channel was summed to represent
the total discharge moving downstream
through the surface-water system (fig.
1, table 1).
Gaging stations closest to the
mouths of tributaries were chosen; for
some tributaries, however, the only
available data were for a station located
some distance upstream from the mouth
of the tributary (fig. 1). At such stations,
the discharge computed at the gaging
station is not necessarily equal to the
discharge that enters the Rio Grande (or
other receiving river). If inflow enters
the tributary between the gaging station
and its confluence with the Rio Grande,
then discharge computed at the gaging
station will be smaller than the actual
volume entering the Rio Grande; this is
most likely to occur in the uppermost
parts of the watershed (for example, at
reference nos. 2 and 3). If diversions or
seepage losses remove water between
the gaging station and its confluence
with the Rio Grande, then discharge
computed at the gaging station will be
larger than the actual volume entering
the Rio Grande; this is most likely to
occur in agricultural areas (for example,
at reference nos. 9, 10, 12, and 20).
Most of the water in the Rio Grande
surface-water system comes from
tributary inflow that originates in the
San Juan or Sangre de Cristo Mountains
and enters the watershed upstream from
Rio Grande at Otowi Bridge, near San
Ildefonso, New Mexico (reference no.
39) (fig. 1). Mean annual discharge at

the following gaging stations represents
tributary inflow from the San Juan
Mountains to the Rio Grande: Rio
Grande at Thirtymile Bridge, near
Creede, Colorado (reference no. 1;
214 ft/s), Willow Creek at Creede,
Colorado (reference no. 3; 22 ft/s),
Goose Creek at Wagon Wheel Gap,
Colorado (reference no. 5; 68 ft/s),
South Fork Rio Grande at South Fork,
Colorado (reference no. 6; 226 ft/s),
and Conejos River near Lasauses,
Colorado (reference no. 18; 193 ft/s).
Mean annual discharge at the following
gaging stations represents tributary
inflow from the Sangre de Cristo
Mountains to the Rio Grande: Red River
below Fish Hatchery, near Questa, New
Mexico (reference no. 22; 85 ft/s), Rio
Pueblo de Taos below Los Cordovas,
New Mexico (reference no. 24; 81 ft/s),
and Embudo Creek at Dixon, New
Mexico (reference no. 26; 99 ft/s).
Most water in the Rio Chama comes
from the southern San Juan Mountains.
The mean annual discharge at gaging
station Rio Chama near Chamita, New
Mexico (reference no. 36; 649 ft/s),
represents tributary inflow from the
southern San Juan Mountains and
includes transmountain diversions to
the Rio Chama, which are measured at
gaging station Azotea Tunnel at Outlet,
near Chama, New Mexico (reference
no. 29; 132 ft/s).
Downstream from the confluence
with the Rio Chama, very little water
enters the Rio Grande (fig. 1). Mean
annual discharge at gaging station
Jemez River below Jemez Canyon Dam,
New Mexico (reference no. 47; 77 ft/s),
represents tributary inflow from the
Jemez Mountains. Other tributary
inflow is from small perennial streams
that drain the southern Sangre de Cristo
Mountains or ephemeral streams that
drain the lower altitudes of the
watershed.
Many factors in the Rio Grande
watershed (see "Hydrologic
Description of the Rio Grande
Watershed") cause discharge to vary
along the Rio Grande. Increases occur
when inflows to the surface-water
system exceed outflows from the
system. Discharge decreases when
outflows exceed inflows. Inflows to the
surface-water system include tributary
inflow, return flows from irrigated
areas, inflow from the ground-water
system, and effluent discharge from
wastewater-treatment plants. Outflows
from the surface-water system include
irrigation diversions,
evapotranspiration by riparian
vegetation, evaporation from open-
water surfaces, and losses to the
ground-water system. Increases and
decreases in mean annual discharge may
be estimated for any given reach (the
area of the watershed between any two
gaging stations) of the Rio Grande by
comparing all measured inflow (which
includes mean annual discharge at the
upstream gaging station as well as that
of any tributaries) with all measured
outflow (the mean annual discharge at
the downstream gaging station). In
some cases, relatively small increases
or decreases may be due to the error
associated with the computed mean
annual discharge at particular gaging
stations.
As shown in figure 1, most increases
in discharge along the Rio Grande are
caused by tributary inflow. In some
cases, increases in mean annual
discharge in the Rio Grande or Rio
Chama cannot be fully accounted for by
the tributary inflow shown in figure 1.
This could be due to inflow from
ungaged tributaries (tributaries where
streamflow is not measured) or to
ground-water inflow. For example,
between gaging stations Rio Grande at
Thirtymile Bridge, near Creede,
Colorado (reference no. 1), and Rio
Grande at Wagon Wheel Gap, Colorado
(reference no. 4), approximately 320
ft/s can be attributed to ungaged
tributaries and ground-water inflow.
The reach between gaging station Rio
Grande near Lobatos, Colorado
(reference no. 19), and the mouth of Red
River receives approximately 90 ft/s of
ground-water inflow annually
(Winograd, 1959).
Discharge decreases by
approximately 640 ft/s in the reach
between the Colorado gaging stations
Rio Grande near Del Norte (reference
no. 7) and Rio Grande at Alamosa
(reference no. 8) and by approximately
170 ft/s in the reach between San
Acacia, New Mexico (reference nos. 56,
57, and 58), and San Marcial, New
Mexico (reference nos. 59 and 60) (fig.
1, table 1).
Discharge appears to decrease by
approximately 207 ft/s in the reach
between gaging stations Rio Grande at
San Felipe, New Mexico (reference no.
45), and Rio Grande at Albuquerque,
New Mexico (reference no. 48). Actual
decreases in mean annual discharge
cannot be determined for this reach,
however, because of the presence of
ungaged streamflow in channels
adjacent to the river.
Tributaries draining the
mountainous regions in the northern
part of the watershed are the largest
sources of water to the Rio Grande.
Irrigation, the largest category of
surface-water use in the Rio Grande
watershed, generally results in
decreases in mean annual discharge
throughout the surface-water system.
Mean annual discharge in the Rio
Grande generally decreases
downstream from the confluence with
the Rio Chama.
References
Ellis, S.R., Levings, G.W., Carter, L.F.,
Richey, S.F., and Radell, M.J., 1993,
Rio Grande Valley, Colorado, New
Mexico, and Texas: Water Resources
Bulletin, v. 29, no. 4, p. 617-645.
Linsley, R.K., and Franzini, J.B., 1972,
Water resources engineering:
McGraw Hill, 690 p.
Richey, S.F., and Ellis, S.R., 1993,
National Water Quality Assessment
Program--Water use in the Rio
Grande Valley, 1990: U.S. Geological
Survey Open-File Report
93-456, p. 1.
Rio Grande Compact Commission,
2001, Report of the Rio Grande
Compact Commission 2000, 68 p.
U.S. Army Corps of Engineers, 2002,
Upper Rio Grande Water Operations
Model: -
http://www.spa. usace.army.mil/
Urgscripts/getData.pl (accessed
December 2002).
Wilson, B.C., and Lucero, A.A., 1997,
Water use by categories in New
Mexico counties and river basins,
and irrigated acreage in 1995: New
Mexico State Engineer Office
Technical Report 49, 149 p.
Winograd, I.J., 1959, Ground-water
conditions and geology of Sunshine
Valley and western Taos County, New
Mexico: New Mexico State Engineer
Technical Report 12, 70 p.
milliºn

For more information contact:
District Chief
U.S. Geological Survey
5338 Montgomery Blvd. NE, Suite 400
Albuquerque, NM 87.109-1311
Email:
lsweiss(a)usgs.gov
Internet:
http://nm.water.usgs.gov