SUMMARY OF FLOW LOSS BETWEEN 

SELECTED CROSS SECTIONS ON THE 

RIO GRANDE IN AND NEAR 

ALBUQUERQUE, NEW MEXICO

Prepared in cooperation with the

CITY OF ALBUQUERQUE

U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 02-4131
U.S. GEOLOGICAL SURVEY

Water-Resources Investigations Report 02-4131

SUMMARY OF FLOW LOSS BETWEEN 

SELECTED CROSS SECTIONS ON THE 

RIO GRANDE IN AND NEAR 

ALBUQUERQUE, NEW MEXICO

Prepared in cooperation with the

CITY OF ALBUQUERQUE

By Jack E. Veenhuis

Albuquerque, New Mexico

2002
U.S. DEPARTMENT OF THE INTERIOR

GALE A. NORTON, Secretary

U.S. GEOLOGICAL SURVEY

Charles G. Groat, Director

The use of firm, trade, and brand names in this report is for identification purposes only and does

not constitute endorsement by the U.S. Geological Survey.

For additional information write to: Copies of this report can be purchased

U.S. Geological Survey

Information Services

Box 25286

Denver, CO 80225-0286

District Chief 

U.S. Geological Survey 

Water Resources Division 

5338 Montgomery Blvd. NE, Suite 400 

Albuquerque, NM 87109-1311

from:

Information regarding research and data-collection programs of the U.S. Geological Survey is available 

on the Internet via the World Wide Web. You may connect to the home page for the New Mexico District 

Office using the URL http://nm.water.usgs.gov.
iii

CONTENTS

Page

Abstract.................................................................................................................................................................................. 1

Introduction ........................................................................................................................................................................... 1

Purpose and scope ....................................................................................................................................................... 4

Hydrologic setting ....................................................................................................................................................... 4

Previous studies ........................................................................................................................................................... 7

Methods ....................................................................................................................................................................... 9

Acknowledgments ....................................................................................................................................................... 9

Flow loss in and near Albuquerque ....................................................................................................................................... 10

Principles of flow-loss measurement........................................................................................................................... 10

Hydrologic characteristics of the measurement reach................................................................................................. 15

Flow relations between measured and gaged cross sections ....................................................................................... 15

Flow loss between cross sections and daily variation in riverflow .............................................................................. 20

Summary................................................................................................................................................................................ 24

References cited..................................................................................................................................................................... 30

FIGURES

1. Map showing study area and generalized extent of the Rio Grande drainage basin above

Fort Quitman, Texas ........................................................................................................................................... 2

2. Map showing streamflow-gaging stations, return-flow measurement sites, riverside drains, and cross-section

locations on the Rio Grande ............................................................................................................................... 3

3. Schematic showing locations of streamflow-gaging stations, riverside drains, and return-flow measurement

sites along the Rio Grande in and near Albuquerque ......................................................................................... 5

4-11. Graphs showing:

4. Monthly distribution of flow at the Rio Grande at Albuquerque streamflow-gaging station before and

after the construction of Cochiti Reservoir in 1973..................................................................................... 6

5. Annual maximum instantaneous peak flow at the Rio Grande at Albuquerque streamflow-gaging

station, 1942-98 ........................................................................................................................................... 7

6. Cross section at the Rio Grande near Bernalillo streamflow-gaging station showing variations in

channel depth for three successive measurements made about 40 minutes apart as part

of the current study ...................................................................................................................................... 10

7. Stage-discharge relations at the Rio Grande near Alameda and Rio Grande at Rio Bravo Bridge

streamflow-gaging stations, 1989-95........................................................................................................... 12

8. Discharge for and average absolute difference between three successive flow measurements at the

Rio Grande near Bernalillo and Rio Grande at Rio Bravo Bridge streamflow-gaging stations,

1996-2000.................................................................................................................................................... 13

9. Absolute change in daily mean flow on 2 consecutive days at the Rio Grande at Albuquerque

streamflow-gaging station during the winter nonirrigation and summer irrigation seasons,

1974-2000.................................................................................................................................................... 14

10. Cochiti Reservoir releases, May 1999 .............................................................................................................. 14

11. Mean monthly flow of the Rio Grande and riverside drains and canals at the Rio Grande at

Albuquerque streamflow-gaging station, 1974-2000................................................................................... 16

12. Schematic showing stage differences of the Rio Grande and riverside drains at the Rio Grande near

Bernalillo and Rio Grande at Rio Bravo Bridge streamflow-gaging stations, February 18, 2000..................... 17
iv

Page

13-23. Graphs showing:

13. Water temperatures at two Rio Grande streamflow-gaging stations and selected riverside drain sites,

1996-2000 ................................................................................................................................................... 18

14. Comparison of total cross-sectional daily mean flow at selected streamflow-gaging stations for the

winter nonirrigation season ......................................................................................................................... 21

15. Total inflow and total outflow for the U.S. Geological Survey paired cross-sectional flow-measurement

study (Hansen, 1995) from the Bernalillo Highway 44 Bridge to the Isleta I-25 Bridge gaging stations

for the summer and winter seasons, August 1993 through February 1995................................................. 22

16. Total inflow and total outflow for the U.S. Geological Survey paired cross-sectional flow-measurement

study (Thorn, 1995) from the Rio Grande near Alameda to the Rio Grande at Rio Bravo

Bridge gaging stations for the summer and winter seasons, 1989-95......................................................... 23

17. Total inflow and total outflow for the U.S. Geological Survey paired cross-sectional flow-measurement

study (current study) from the Rio Grande near Bernalillo to the Rio Grande at Rio Bravo Bridge 

gaging stations for the winter season, December through February, 1996-2000........................................ 25

18. Absolute change in daily mean flow for 2 consecutive measurement days at the Rio Grande at

Albuquerque streamflow-gaging station during the winter nonirrigation and summer irrigation

seasons, 1989-2000 ..................................................................................................................................... 25

19. Daily differences in flow in relation to distance between selected streamflow-gaging stations for the

winter nonirrigation season ......................................................................................................................... 26

20. Difference in measured cross-sectional flow in relation to distance for the three paired flowmeasurement studies ................................................................................................................................... 26

21. Percent daily mean flow loss of the Rio Grande for three measurement studies and three streamflowgaging stations............................................................................................................................................. 28

22. Median flow loss of the Rio Grande for three measurement studies and three streamflow-gaging stations

by reach length ............................................................................................................................................ 29

23. Flow loss in relation to the change for 2 consecutive days of daily mean flow at the Rio Grande at

Albuquerque streamflow-gaging station, 1996-2000 .................................................................................. 30

TABLES

1. Winter nonirrigation season river and riverside drain flows, 1996-2000................................................................. 8

2. Winter nonirrigation season return flows between the Rio Grande near Bernalillo and Rio Grande at

Rio Bravo Bridge streamflow-gaging stations ................................................................................................... 16

3. Regression equations for total downstream cross-sectional flow in relation to total upstream

cross-sectional flow............................................................................................................................................ 19

4. Estimated flow loss between cross sections on the Rio Grande in and near Albuquerque ..................................... 27

CONVERSION FACTORS AND VERTICAL DATUM

Sea level: In this report, "sea level" refers to the National Geodetic Vertical Datum of 1929—a 

geodetic datum derived from a general adjustment of the first-order level nets of the United States 

and Canada, formerly called Sea Level Datum of 1929.

Multiply By To obtain

inch 2.54 centimeter

foot 0.3048 meter

mile 1.609 kilometer

cubic foot per second 0.02832 cubic meter per second
1

ABSTRACT

The upper middle Rio Grande Basin, as defined 

by the U.S. Army Corps of Engineers, extends from the 

headwaters of the Rio Grande in southwestern 

Colorado to Fort Quitman, Texas. Most of the basin has 

a semiarid climate typical of the southwestern United 

States. This climate drives a highly variable streamflow 

regime that contributes to the complexity of water 

management in the basin. Currently, rapid population 

growth in the basin has resulted in increasing demands 

on the hydrologic system. Water management 

decisions have become increasingly complex because 

of the broad range of interests and issues. For these 

reasons, the U.S. Geological Survey, in cooperation 

with the City of Albuquerque, New Mexico, conducted 

paired flow measurements at two cross sections to 

determine cross-sectional loss in the Albuquerque 

reach of the Rio Grande.

This report statistically summarizes flow losses 

in the Albuquerque reach of the Rio Grande during the 

winter nonirrigation season from December 1996 to 

February 2000. The two previous flow-loss 

investigations are statistically summarized. Daily mean 

flow losses are calculated for the winter nonirrigation 

season using daily mean flows at three selected Rio 

Grande streamflow-gaging stations.

For the winter nonirrigation season crosssectional measurements (1996-2000), an average of 

210 cubic feet per second was returned to the river 

between the measurement sites, of which 165 cubic 

feet per second was intercepted by riverside drains 

along the 21.9-mile reach from the Rio Grande near 

Bernalillo to the Rio Grande at Rio Bravo Bridge 

streamflow-gaging stations. Total cross-sectional 

losses in this reach averaged about 90 cubic feet per 

second. 

Regression equations were determined for 

estimating downstream total outflow from upstream 

total inflow for all three paired measurement studies. 

Regression equations relating the three daily mean flow 

recording stations also were determined. In each 

succeeding study, additional outside variables were 

controlled, which provided more accurate flow-loss 

measurements. Regression-equation losses between 

measurement cross sections ranged from 1.9 to 7.9 

percent during the nonirrigation season and from about 

5.9 to 6.4 percent during the irrigation season. Mean 

and median loss by reach length for all three daily mean 

flow stations and all three cross-sectional measurement 

reaches showed consistent flow loss per mile by season 

with allowance for nonideal river conditions for the 

initial measurement studies. Unsteady measurement 

conditions were reflected in the regression equation 

mean-square errors and ultimately in the change in 

daily mean discharge at the Rio Grande at Albuquerque 

gaging station during the measurement periods.

Introduction

The upper Rio Grande Basin, as defined by the 

U.S. Army Corps of Engineers, extends from the 

headwaters of the Rio Grande in south-central 

Colorado to Fort Quitman, Texas (fig. 1). Most of the 

basin has a semiarid climate typical of the 

southwestern United States. This climate drives a 

highly variable streamflow regime that contributes to 

the complexity of water management in the basin. 

Average annual precipitation ranges from about 7 to 15 

inches over the upper and middle parts of the basin and 

exceeds 25 inches only in the high mountain areas.

Historically, water from the Rio Grande has been 

used primarily for crop irrigation. Currently, rapid 

population growth in the basin has resulted in 

increasing demands on the hydrologic system; thus, 

water management decisions have become 

increasingly complex. Riverflow losses and sources of 

ground-water recharge are becoming increasingly 

important. Flow-loss estimates in the Albuquerque 

reach of the Rio Grande are needed to help determine 

recharge to the Santa Fe Group aquifer system that 

Albuquerque depends on for its public water supply. 

This reach extends from south of Bernalillo to the Rio 

Bravo Bridge in the southern part of Albuquerque 

(fig. 2). 

SUMMARY OF FLOW LOSS BETWEEN SELECTED 

CROSS SECTIONS ON THE RIO GRANDE IN AND 

NEAR ALBUQUERQUE, NEW MEXICO

By Jack E. Veenhuis
2 
3
4 

For these reasons, the U.S. Geological Survey 

(USGS), in cooperation with the City of Albuquerque, 

conducted paired-flow measurements at two river cross 

sections to determine riverflow loss in the Albuquerque 

reach of the Rio Grande. Cross-sectional flow 

measurements were made along this reach at two 

streamflow-gaging stations: Rio Grande near 

Bernalillo (08329500) and Rio Grande at Rio Bravo 

Bridge (08330150). The measurements were 

conducted during four winter nonirrigation seasons 

from December 1996 to February 2000.

Purpose and Scope

This report presents the results of a flow-loss 

study in the Albuquerque reach of the Rio Grande 

during the winter nonirrigation season from December 

1996 to February 2000 and compares these results with 

two previous flow-loss investigations. These two 

investigations were conducted on the Bernalillo to 

Isleta, New Mexico, reach of the Rio Grande. In 

addition, the quantity of water riverside drains 

intercept, the quantity of water that returns to the river, 

and stage differences between the riverside drains and 

the river were measured.

As a part of one of these flow-loss investigations, 

two streamflow-gaging stations were operated at the 

cross sections used in that study. The daily mean flow 

loss during the winter nonirrigation season was 

calculated between the daily mean flow at these two 

gaging stations and a long-term streamflow-gaging 

station in the middle of the measurement reach.

Hydrologic Setting

A discussion of flow characteristics of the Rio 

Grande and the storm-drain system is important for 

understanding the complex flow system in the 

Albuquerque area. The Rio Grande flow system in the 

Albuquerque reach consists of the river channel, 

irrigation canals, return-flow drains, and riverside 

drains (fig. 3). From March through October, part of the 

Rio Grande is diverted upstream from Bernalillo and 

flows through irrigation-supply canals to fields. Some 

of this flow returns to the river through return-flow 

drains and canals. In addition, riverside drains on either 

side of the river channel intercept channel-seepage 

water that prior to 1930 would have waterlogged 

adjacent fields that are substantially below the water 

level of the river. During November through February 

water is not diverted to canals, so the entire flow is 

conveyed by the river channel and riverside drains. 

These riverside drains intercept lateral seepage from 

both sides of the river and return this flow to the river at 

several locations.

The annual variation of streamflow of the Rio 

Grande is characteristic of a river whose flow is mostly 

a result of snowmelt. Most of this runoff comes from 

snow that has fallen in the mountains of the upper Rio 

Chama Basin, the upper Rio Grande in the San Luis 

Valley in Colorado, and the upper Rio Grande in New 

Mexico (fig. 1). Snowmelt runoff is highest in May or 

early June and at its lowest in the fall and winter. In 

addition, summer monsoon thunderstorm runoff is 

superimposed on this streamflow regime. Gulf of 

Mexico moisture supplies about 40 percent of New 

Mexico precipitation in the form of summer 

thunderstorms (Scott Waltemeyer, U.S. Geological 

Survey, written commun., 2001). Most thunderstorms 

occur in July, August, and September and can result in 

local, intense rainfall and runoff. This highly localized 

runoff can add substantial flow to a much reduced 

riverflow near the end of summer when water use is at 

a maximum.

Cochiti, Galisteo, and Jemez Reservoirs (fig. 1), 

located upstream from Albuquerque, substantially 

influence riverflow downstream. These reservoirs 

control flood flows from about 90 percent of the 

contributing upstream drainage area. As a result, Rio 

Grande flow through Albuquerque is an attenuated 

version of a characteristic snowmelt streamflow cycle 

with an occasional superimposed summer 

thunderstorm inflow downstream from these three 

reservoirs. Except for the substantial reduction in the 

variation of flow in May and June, monthly flow 

distributions are quite similar to distributions prior to 

the construction of Cochiti Reservoir in 1973 (fig. 4). 

The annual peak flow recorded at the Rio Grande at 

Albuquerque gaging station (fig. 2), water years 1942-

98, and the effect of Cochiti Reservoir on peak flow 

since 1973 are shown in figure 5.

At the Rio Grande at Albuquerque gaging station 

(fig. 2), riverside drains, irrigation canals, or laterals 

convey flow during the entire year. From November 

through February, riverside drains adjacent to both 

sides of the river and lower than the water surface of the 

Rio Grande collect river-water seepage and return it to 

the river downstream (fig. 3). From March through 

October, these drains also convey irrigation-return
5
6 
7

flows as well as river-water seepage intercepted from 

the river. Flow in the drains averages about 14 percent 

of total annual flow of the river at this gaging station, 

but can range from a high of 36 percent of total crosssectional flow in a dry year to as little as 5 percent of 

total flow in a wet year.

Flow is conveyed in irrigation canals about 8 

months of the year. Riverside drains convey flow the 

entire year; drain flow during the nonirrigation season 

consists primarily of river-intercepted bed seepage that 

is returned to the river as drain-return flow. The change 

in the source of riverside drain water is visibly evident 

because flow during the nonirrigation months 

(November through February) is cold and clear due to 

its river seepage ground-water source. Flow in these 

riverside drains increases in the downstream direction. 

Because flow gradients in the drains are smaller than 

those in the river, the channel bottoms of the drains 

gradually rise until the water surface of the drain is 

higher than that of the river. At the point where the 

water surface of the drain becomes higher than that of 

the river, this intercepted seepage water is returned to 

the river. Where the water surface in a drain is equal to 

the water level of the river, a second drain at a lower 

elevation and outside the first drain begins intercepting 

river leakage. Increases in riverside-drain flow per mile 

vary depending on distance from the river to the drain, 

soil permeability, and riverside-drain elevation relative 

to the Rio Grande. Riverside-drain inflows and 

outflows measured from December 1996 to February 

2000 are listed in table 1.

Previous Studies

Flow-loss studies conducted on the Rio Grande 

in Albuquerque include an intensive monthly flow-loss 

investigation by Thorn (1995) and a weekly flow-loss 

investigation by Hansen (1995). These studies are 

summarized below.

Thorn (1995) measured flow monthly from 1989 

to 1995 at two cross sections established near two 

gaging stations: Rio Grande near Alameda (08329928) 

and Rio Grande at Rio Bravo Bridge near Albuquerque 

(08330150) (fig. 2). Sixty-one paired measurements 

were made at the two cross sections, 22 during the 

winter nonirrigation season and 39 during the summer 

irrigation season. Flow was measured in the morning at 

the upstream Alameda cross section and in the 

afternoon at the downstream Rio Bravo Bridge cross 

section in an attempt to measure the same water.

Figure 5. Annual maximum instantaneous peak flow at the Rio Grande at Albuquerque (08330000)

streamflow-gaging station, 1942-98. Location of gaging station shown in figure 2.

Before Cochiti Reservoir

was constructed in 1973

After Cochiti Reservoir

was constructed in 1973

0

5,000

10,000

15,000

20,000

25,000

ANNUAL PEAK FLOW, IN CUBIC FEET PER SECOND

1940 1950 1960 1970 1980 1990 2000

WATER YEAR
8 

Table 1. Winter nonirrigation season (December through February) river and riverside drain

flows, 1996-2000

[All flows in cubic feet per second. *, missing values]

Year Month

Date(s) 

cross 

section 

measured

Threemeasurement 

mean 

river 

inflow

Riverside 

drain 

inflow

Wastewater 

inflow

Threemeasurement 

mean 

river 

outflow

Riverside 

drain 

outflow

Mass 

inflow

Mass 

outflow

Inflow 

minus 

outflow 

gain (-) 

or loss

1996 Dec 3-4 610 66 2 597 41 678 638 40

1996 Dec 11-12 709 67 1 711 42 777 753 24

1996 Dec 17 757 66 2 * * 825 * *

1997 Jan 22-23 792 61 2 897 38 855 935 -80

1997 Jan 28-29 966 59 2 * 38 1,027 * *

1997 Feb 4-5 789 63 2 843 37 854 880 -26

1997 Feb 11-12 819 70 2 767 36 891 803 88

1997 Feb 25-26 808 71 2 724 38 881 762 119

1997 Dec 17-18 1,060 114 3 1,070 42 1,177 1,112 65

1998 Jan 8-9 1,143 108 3 1,085 38 1,254 1,123 131

1998 Jan 14-15 1,033 105 3 1,003 40 1,141 1,043 98

1998 Jan 21-22 858 102 3 841 40 963 881 82

1998 Jan 28-29 876 105 3 990 37 984 1,027 -43

1998 Feb 11-12 979 99 3 924 38 1,081 962 119

1998 Feb 18-19 983 96 3 945 35 1,082 980 102

1998 Feb 25-26 948 99 3 846 34 1,050 880 170

1998 Dec 9-10 679 87 2 635 45 768 680 88

1998 Dec 16-17 760 87 2 720 44 849 764 85

1999 Jan 6-7 965 85 4 925 43 1,054 968 86

1999 Jan 13-14 925 80 4 825 40 1,009 865 144

1999 Jan 27-28 894 82 3 881 40 979 921 58

1999 Feb 3-4 812 81 3 742 39 896 781 115

1999 Feb 18-19 968 76 4 934 40 1,048 974 74 

1999 Mar 1 570 78 2 772 40 * * *

2000 Feb 18-19 847 102 2 791 37 951 828 123

Rio Grande near 

Bernalillo

cross section

Rio Grande at Rio 

Bravo Bridge

cross section
9

Measurements were made when storm-water inflows 

were not occurring and when riverflow appeared to be 

steady. No wastewater-treatment inflows enter between 

the two cross sections and no known surface-water 

inflows exist between the two sites. Cross-sectional 

flows measured from 1989 to 1995 ranged from 

approximately 22 to more than 5,900 cubic feet per 

second (ft3

/s) with a corresponding change in river 

stage of about 3.8 feet between the lowest and highest 

flows measured.

In the second study, the Bureau of Reclamation 

(BOR) (Hansen, 1995) made 69 weekly flow 

measurements between August 1993 and February 

1995 at two cross sections: the Highway 44 Bridge 

north of Bernalillo and the Isleta I-25 Bridge north of 

the Rio Grande at Isleta gaging station (fig. 2). To 

determine streamflow loss, measurements were made 

at the upstream site in the afternoon and at the 

downstream site the next day. Twenty-five 

measurements were made during the winter 

nonirrigation season and 44 were made during the 

summer irrigation season. During this study, four 

wastewater inflows entered the river between the 

upstream and downstream cross sections. Major stormwater tributary inflows were documented, and 

reservoir-release changes were determined from 

streamflow records.

Methods

The Rio Grande near Alameda and the Rio 

Grande at Rio Bravo Bridge gaging stations (fig. 2) 

were operated as part of the Thorn (1995) flowmeasurement investigation from March 1989 to 

September 1995 and from January 1991 to September 

1995, respectively. The Rio Grande near Bernalillo 

gaging station was operated for stage during the current 

study (1996-2000). The Rio Grande at Albuquerque 

gaging station has been operated since October 1941 as 

part of other data collection efforts.

Waltemeyer (1994) conducted a study during the 

fall of 1991 to estimate travel time and reaeration for a 

reach of the Rio Grande extending from the Rio Grande 

Nature Center to the gaging station at the Isleta 

Diversion Dam. The study concluded that the 

streamflow velocity of the Rio Grande between the Rio 

Grande Nature Center and the Isleta Diversion Dam 

ranged from 1 to 2 miles per hour for discharges 

ranging from 250 to 1,500 ft3

/s. This range of velocities 

was used to estimate the time a parcel of water would 

travel from the upstream measurement site to the 

downstream measurement site.

During the winter nonirrigation season from 

December 1996 to February 2000 (current study), the 

USGS conducted a paired flow-measurement 

investigation. Twenty-five paired measurements of the 

river and riverside drains were made at two cross 

sections: the Rio Grande near Bernalillo and the Rio 

Grande at Rio Bravo Bridge gaging stations (fig. 2). 

Streamflow was measured at the upstream site in the 

afternoon and at the downstream site the next morning. 

Because these were winter season measurements, only 

the river and riverside drains at each cross section were 

measured. Minimal wastewater-return flows were 

recorded in this reach, and streamflow measurements 

were conducted when storm-water inflows were not 

occurring. The U.S. Army Corps of Engineers 

maintained constant releases from Cochiti and Jemez 

Reservoirs for 3 days prior to the measurements. As 

part of the flow-measurement procedure, air 

temperature and water temperature also were 

measured. To help avoid bias, most measurements were 

made by the same person or two people at the same 

time.

Riverside drain-return flow (where drain flow 

discharges to the river) was measured annually at four 

sites (fig. 2): Sandia Lakes return, Corrales Riverside 

Drain near Corrales gaging station, Oxbow return, and 

Central Avenue return (fig. 3). Return flow was 

presumed to be riverbed seepage. Return flows were 

added to the cross-sectional flow between cross 

sections to calculate total river-channel loss along this 

reach.

The difference between the elevation of the stage 

of the river and the elevation of the water surface of the 

riverside drain was measured once during flow 

measurements in February 2000. The gradient between 

the river and the riverside drain drives river leakage that 

is intercepted and returned to the river by the drains.

Acknowledgments

The author acknowledges personnel of the 

USGS Albuquerque Field Office for their help in 

making streamflow measurements. Also, the author 

acknowledges Reservoir Operations personnel at the 

U.S. Army Corps of Engineers for their cooperation in 

maintaining constant releases from Cochiti and Jemez 

Reservoirs during the current investigation.
10 

FLOW LOSS IN AND NEAR 

ALBUQUERQUE

Principles of Flow-Loss Measurement

Measuring flow loss in the Rio Grande presents 

a somewhat difficult task. Rio Grande streamflow 

channels are constantly changing in response to daily, 

monthly, and annual variations in flow, sediment 

supply, and the formation of sand bars. All Rio Grande 

flow-measurement and gaging-station sites in and near 

Albuquerque are characterized by wide sand channels. 

The variations in channel depth necessitate frequent 

flow measurements to update stage-discharge relations 

because a large flow can easily change the stage as 

much as 2 feet for a given discharge. Thus, constant and 

episodic channel-bed changes result in changing stagedischarge relations and subsequently daily mean flows. 

Stage-discharge relations are a function of the rate of 

channel change and the length of time since the last 

measurement. Variations in channel depth during three 

successive measurements about 40 minutes apart at the 

Rio Grande near Bernalillo gaging-station cross 

section are shown in figure 6.

The following principles were used to make 

more accurate flow-loss measurements between two 

sites on the Rio Grande near Bernalillo and Rio Grande 

at Rio Bravo Bridge gaging stations (fig. 2). (1) The 

stations were far enough apart that field personnel 

could measure the difference in daily mean flows 

considering the additional error inherent in the stagedischarge relation. (2) All cross-sectional flow was 

measured at both sites because there is usually transfer 

of flow between the conveyances that makes individual 

conveyance flow differences meaningless. (3) Crosssectional flow was measured in the winter when there 

is less evapotranspiration and no routing of irrigation 

flow across the valley. (4) The error in measurement 

was reduced by measuring the river three successive 

times because of the constantly changing sand channel. 

(5) Cross-sectional flow was not measured during 

stormflow, and wastewater inflows were documented. 

(6) Reservoir releases were controlled so inflow to the 

reach was steady. (7) Travel time of the water was 

determined so that the same water was measured 

downstream.
11

The flow measurements in relation to stage of the 

Rio Grande near Alameda and Rio Grande at Rio Bravo 

Bridge gaging stations from 1989 to 1995 are shown in 

figure 7. Flow in the Rio Grande through Albuquerque 

can increase from about 22 to more than 5,900 ft3/s 

with about a 3.8-foot increase in stage. For this short 

(12.9-mile) reach of the river (fig. 2), the difference in 

daily mean flow between the two gaging stations may 

be masked by errors in the stage-discharge rating at 

each site. These errors are a combination of error in the 

measurement of flow at each site and error caused by 

the changing relation between stage and discharge. 

Each measurement updates this relation, which then 

can be used to compute daily discharge. The computed 

daily discharge at each site depends on the recorded 

stages for the day and the applicable stage-discharge 

relation. Frequent discharge measurements were made 

to update the stage-discharge relation.

In the Albuquerque reach, flow seeps from the 

river to a riverside drain and is returned back to the 

river within a selected reach; thus, flow was measured 

in the channel and drains at each cross section to 

compare flow loss or gain between cross sections. 

Comparing all flow at one cross section to all flow at 

another cross section is the only meaningful way to 

make accurate flow-loss estimates.

In the current (1996-2000) study, flow 

measurements were restricted to the winter 

nonirrigation season (November through February) to 

help simplify and reduce variability of flow. This also 

eliminates travel-time differences for irrigation water 

that flows down a much longer path through the valley. 

Also, evapotranspiration during the summer can be 

substantial. Hansen (1985) estimated that summer 

evapotranspiration loss ranged from 8.6 to 54 ft3/s for 

the 32-mile reach. In the current study, estimated 

evapotranspiration ranged from 2 to 4 ft3

/s of the crosssectional loss, and transpiration was estimated to be 

negligible during the 4 winter months. Evaporation was 

estimated by multiplying the average monthly pan 

evaporation times the total water surface between the 

cross sections, the river, and riverside drains.

Three successive measurements were conducted 

on the river to reduce measurement error at both gaging 

stations. For these measurements, upstream river mean 

inflow ranged from 570 to 1,143 ft3/s (table 1); 

riverside drain inflow at the Rio Grande near Bernalillo 

(one drain on the east side of the river) ranged from 59 

to 114 ft3/s. At the downstream gaging station (Rio 

Grande at Rio Bravo Bridge) river mean outflow 

ranged from 597 to 1,085 ft3/s and riverside drain 

outflow ranged from 34 to 45 ft3

/s (table 1). Because 

flow in the river is about 8 to 10 times flow in the drains 

and the error is about the same percentage for the river 

and riverside drains, measuring the riverside drain three 

successive times was not necessary. The riverside 

drains also have a more stable channel bottom, so in 

effect measuring the river three successive times is the 

most efficient way to decrease the total inflow and 

outflow measurement error. The median of the average 

absolute difference between the three successive river 

measurements as a percentage of the three 

measurements was 3.1 at Rio Grande near Bernalillo 

and 3.1 at Rio Grande at Rio Bravo Bridge (fig. 8).

For a more accurate flow-difference 

measurement, storm water, wastewater, or irrigation 

water should not enter the measurement reach. During 

the current study (1996-2000) two small documented 

wastewater flows entered the reach. 

A constant release from Cochiti and Jemez 

Reservoirs (fig. 1) was necessary for accurate flow 

measurements. If flow is changing, the difference 

between two flow measurements may be due to 

nonsteady flow or interchange of water in bank storage. 

Daily flow of the Rio Grande in and near Albuquerque 

is primarily a result of releases from Cochiti Reservoir. 

Releases are varied to maintain a constant watersurface area in the reservoir. The Rio Grande at Otowi 

Bridge gaging station (fig. 1) records flows from 

watersheds that are about 80 percent unregulated. 

Thus, releases from Cochiti Reservoir are adjusted at 

least daily to match reservoir outflow to inflow. As a 

result, the median absolute change in daily mean flow 

for 2 consecutive days at the Rio Grande at 

Albuquerque gaging station is about 40 ft3/s for the 

winter nonirrigation season and 69 ft3/s for the summer 

irrigation season (fig. 9). Cochiti Reservoir releases for 

May 1999 illustrate the constant adjustment of outflow 

to inflow (fig. 10). The controlled releases from Jemez 

Reservoir and occasionally Galisteo Reservoir result in 

constantly changing flow in the Rio Grande. Changes 

in diversion, return flow during the 8-month irrigation 

season, and highly variable and localized storm inflow 

during the monsoonal season add to the variability of 

flow.
12 
13
14 
15

For the 1996-2000 study, flow in the Rio Grande 

was measured at the Rio Grande near Bernalillo cross 

section in the late afternoon and at the Rio Grande at 

Rio Bravo Bridge cross section the following morning. 

For the range of riverflows (table 1), the time between 

measurements was slightly longer than the travel time 

of water determined for this reach. This slight 

discrepancy has little effect on flow differences 

between two sites.

Hydrologic Characteristics of the 

Measurement Reach

Riverside drain flow during the summer 

irrigation season (March through October) at the Rio 

Grande near Bernalillo, Rio Grande near Alameda, Rio 

Grande at Albuquerque, and Rio Grande at Rio Bravo 

Bridge cross sections (fig. 2) is a combination of 

irrigation-return flow and river seepage that is 

intercepted by the riverside drains. River seepage 

constitutes total flow in drains during the nonirrigation 

season. From 1989 to 1995, riverside-drain flow ranged 

from 75 to 245 ft3/s (Thorn, 1995) during the summer 

irrigation season at the Rio Grande near Alameda and 

Rio Grande at Rio Bravo Bridge cross sections.

During the winter nonirrigation season 

(November through February), flow in the single 

riverside drain east of the Rio Grande near Bernalillo 

cross section averaged about 10 percent of riverflow at 

that site. Drain flow at this cross section did not 

respond to every short-term change in river stage. Only 

long-term variation in riverflow was represented in the 

drain flow at this site, as would be expected for a 

predominantly river-seepage, gradient-controlled 

system. Flow in a drain at a given cross section during 

the nonirrigation season is a combination of the 

location of the cross section with respect to the location 

of the start of the drain and return-flow location and 

flow in the river at the cross section. Flow constantly 

increases from the beginning of a drain to where the 

drain returns flow to the river. Flows in the east- and 

west-riverside drains are highly correlated with each 

other during the nonirrigation season but do not 

immediately reflect rapidly changing riverflows. A 

large increase in riverflow does not produce a large 

increase in stage; increases in drain flow increase in 

proportion to increases in the difference between the 

river and the drain stage. Riverside drain flow at the Rio 

Grande at Albuquerque cross section (fig. 11) averages 

about 30 ft3/s during the nonirrigation season because 

the cross section is only one-half mile downstream 

from the return flow above Central Avenue and about

1.5 miles from the start of that drain. 

Two east riverside drain-return flows are 

between the Rio Grande near Bernalillo and Rio 

Grande at Rio Bravo Bridge gaging stations: one 

located upstream from the Alameda Bridge near Sandia 

Lakes and one about one-half mile upstream from 

Central Avenue (fig. 12). The return flow at these two 

locations averaged 94.4 and 74.5 ft3/s, respectively 

(table 2). The combined west riverside returns, 

Corrales Riverside Drain near the Alameda Bridge and 

Oxbow return north of Interstate 40, averaged 21.5 and 

19.7 ft3/s, respectively (table 2). Total east- and westriverside-drain return flow between the Rio Grande 

near Bernalillo and the Rio Grande at Rio Bravo Bridge 

cross sections averaged about 210 ft3

/s. This flow 

represents the average rate of river seepage from 

November through February returned to the river after 

being intercepted by the drains. The total rate of inflow 

and outflow collected by drains in this 21.9-mile reach 

averaged about 165 ft3

/s (table 2).

Stage differences between the river and riverside 

drains at several locations between Rio Grande near 

Bernalillo and Rio Grande at Rio Bravo Bridge are 

shown in figure 12. These differences ranged from 

-7.21 to +2.40 feet on the west side of the river and 

from -9.66 to +3.09 feet on the east side. Again the 

difference in water-surface elevation controls the 

interception of river-drained leakage and return flow to 

the river.

Water temperature also was measured when 

nonirrigation season cross-sectional flow was 

measured. Selected riverside-drain median water 

temperatures ranged from about 5 to 8 °C warmer than 

river water temperatures (fig. 13). This small difference 

supports the argument that water in the riverside drains 

is primarily river seepage intercepted by the drains.

Flow Relations between Measured and 

Gaged Cross Sections

Measurements at paired streamflow sites on the 

Rio Grande provide data that are highly correlated and 

not statistically independent, especially if the sites are 

in close proximity to one another. For daily discharge 

data computed at gaging stations and also for paired 

individual streamflow-measurement data, the 

downstream measurement statistically is highly 

dependent on the upstream measurement. For this 

reason, regression analysis of dependent downstream 

gaging-station data to independent upstream gagingstation data is an appropriate statistical technique. 
16 

Table 2. Winter nonirrigation season return flows measured between the Rio Grande near

Bernalillo and Rio Grande at Rio Bravo Bridge streamflow-gaging stations

[All flows in cubic feet per second. Location of gaging stations and return-flow sites shown in figure 3]

Date

Sandia 

Lakes 

return

Corrales 

Riverside 

Drain 

return

Oxbow 

return

Central 

Avenue 

return

Total 

returned 

in reach

Total 

collected 

by drains 

in reach

Feb 25, 1997,

 to

Feb 26, 1997

79.2 20.7 19.0 75.9 195 161

Feb 27, 1997,

 to

Feb 28, 1997

98.5 25.0 23.0 82.0 228 164

Mar 1, 1999 86.0 16.3 15.0 71.0 188 148

Feb 17, 2000,

 to

Feb 18, 2000

114 23.9 21.9 69.0 229 186

Average 94.4 21.5 19.7 74.5 210 165
17
18 

For Hansen’s (1995) and Thorn’s (1995) studies, more 

accurate average flow losses could be calculated if flow 

measurements were removed from the analyses when 

unplanned inflow occurred or reservoir releases were 

changed. No measurements were removed prior to any 

of these statistical analyses.

Regression equations for estimated downstream 

total cross-sectional flow in relation to upstream total 

cross-sectional flow for selected gaging stations are 

listed in table 3. Daily mean flows at adjacent upstream 

and downstream gaging stations are generally highly 

correlated. The correlations and winter nonirrigation 

season regression equations for cross-sectional daily 

flow at selected gaging stations are listed in table 3AB. When linear regression analysis is used between two 

paired sets of Rio Grande flows, whether the flows are 

measured or computed daily, the intercept term 

generally tends to not be significantly different from 

zero—that is, there is no constant loss but loss is 

directly related to upstream flow. The slope in the 

regression is statistically significant at a p-value less 

than 0.05. The slope also represents a ratio of daily 

flows or measurements at the downstream site in 

relation to those at the upstream site, or in effect, the 

part of the loss or gain that is directly related to flow. 

Comparing total cross-sectional flow is the only 

valid flow comparison because the individual 

conveyances, such as riverside-drain return flows, are 

interconnected between the cross sections. Daily mean 

flows are highly correlated because the large number of 

days of flow minimizes the error caused by the 

changing stage-discharge relation at each gaging 

station. To compare total cross-sectional daily mean 

flows at the three cross sections, the estimated drain 

flow at each cross section was added to each daily mean 

recorded flow. The winter nonirrigation season crosssectional daily-flow correlations and the distance 

between the cross sections are listed in table 3A-B. 

Also listed are the ratio of daily flow between the sites 

(the slope in regression analysis when the intercept is 

not significantly different from zero) and the average 

ratio of flow loss (1.00 minus the ratio of daily flow 

between the sites). The regression equation and meansquare error relating the total flow at the upstream and 

downstream sites also are listed in table 3A-B. Winter 

nonirrigation season daily mean flows, including the 

estimates for drain flow at each site, yield downstream 

to upstream ratios of daily discharge of 0.981 between 

the Rio Grande at Rio Bravo Bridge and Rio Grande at 

Albuquerque gaging stations, 0.949 between the Rio
19 

(B) Regression equations for total measured cross-sectional flow for three paired measurement

studies for the winter nonirrigation and summer irrigation seasons, 1989-2000

1Data from Hansen (1995)2Data from Thorn (1995)3Data from current study (1996-2000)

Table 3. Regression equations for total downstream cross-sectional flow in relation to total upstream cross-sectional flow

(A) Regression equations for total cross-sectional daily mean flow at the three

streamflow-gaging stations for the winter nonirrigation season, 1996-2000

Gaging-station name and

reach distance (fig. 2)

Season and correlation coefficient 

(corr.)

Regression equation and

mean-square error

Flow loss

(in percent)

Range of total inflow

(cubic feet per second)

Rio Grande at Rio Bravo Bridge (RGRB) to Rio Grande at Albuquerque (RGC) 4.9 miles

WinterCorr. = 0.932

RGRB = 0.981 RGC

8.6 percent

1.9 203 - 2,230

Rio Grande at Albuquerque (RGC) to Rio Grande near Alameda (RGA)8.0 miles

WinterCorr. = 0.943

RGC = 0 .949 RGA

10.1 percent

5.1 217 - 1,830

Rio Grande at Rio Bravo Bridge (RGRB) to Rio Grande near Alameda (RGA) 12.9 miles

WinterCorr. = 0.879

RGRB = 0.930 RGA

12.5 percent

7.0 217 - 1,830

Site or gaging station name and

reach distance (fig. 2)

Season, number of measurements, 

and correlation coefficient (corr.)

Regression equation and

mean-square error

Flow loss

(in percent)

Range of total inflow

(cubic feet per second)

Isleta I-25 Bridge (RGI) to Bernalillo Highway 44 Bridge (RGBB) 32 miles1

Summer 44Corr. = 0 .991Winter 25Corr. = 0.813

RGI = 0 .936 RGBB

14.4 percent

RGI = 0 .976 RGBB

12.5 percent

6.42.4

800 - 7,040842 - 1,660

Rio Grande at Rio Bravo Bridge (RGRB) to Rio Grande near Alameda (RGA) 12.9 miles2

Summer 39Corr. = 0.996Winter 20Corr. = 0.936

RGRB = 0.941 RGA

9.3 percent

RGRB = 0.943 RGA

9.6 percent

5.95.7

321 - 6,310344 - 1,680

Rio Grande at Rio Bravo Bridge (RGRB) to Rio Grande near Bernalillo (RGBG) 21.9 miles3

Winter 22Corr. = 0.902

RGRB = 0.921 RGBG

6.5 percent

7.9 678 - 1,250
20 

Grande at Albuquerque and Rio Grande near Alameda 

gaging stations, and 0.930 between the Rio Grande at 

Rio Bravo Bridge and Rio Grande near Alameda 

gaging stations (table 3A). The total cross-sectional 

daily flow regressions between the three gaging 

stations are shown in figure 14. Summer irrigation 

season daily flows were not compared because 

irrigation flow at each cross section could not be 

quantified.

Weekly cross-sectional flow was measured at the 

Isleta I-25 Bridge and the Bernalillo Highway 44 

Bridge (fig. 2) by the BOR from August 1993 through 

February 1995 (Hansen, 1995) and is summarized by 

two regression equations in table 3B. Hansen used 

USGS-recorded storm inflows and City of 

Albuquerque and City of Rio Rancho recorded 

municipal daily wastewater inflows to account for 

inflow for measurements made during storms and dry 

weather. Storm-water flow was estimated using North 

Floodway and South Diversion Channel daily flows. 

The Rio Grande inner valley and west-side storm-water 

inflow to the Rio Grande was not quantified. Daily 

mean wastewater inflows were accounted for; the 

hourly variation of wastewater discharge was not. 

Reservoir releases were not held constant during 

measurement periods, which probably caused most of 

the variation in the differences in discharge 

measurements at the Isleta and Bernalillo sites. Crosssectional measurements also included flow during the 

summer irrigation and winter nonirrigation seasons. 

Total measured outflow in relation to total measured 

inflow for this reach for the summer irrigation and 

winter nonirrigation seasons is shown in figure 15. The 

regression analysis ratios of downstream to upstream 

cross-sectional flow were 0.936 for the 44 summer 

measurements and 0.976 for the 25 winter 

measurements for this 32-mile reach (table 3B). These 

flow ratios apply for upstream cross-sectional total 

inflows ranging from 800 to 7,040 ft3

/s for the summer 

irrigation season and from 842 to 1,660 ft3

/s for the 

winter nonirrigation season. The mean-square error 

was 14.4 percent for the irrigation season and 12.5 

percent for the nonirrigation season.

Cross-sectional flow measurements were made 

from 1989 to 1995 by the USGS (Thorn, 1995) at the 

Rio Grande at Rio Bravo Bridge and Rio Grande near 

Alameda gaging stations. Measurements were not 

made during storm-water inflow, and wastewater 

inflow did not enter the river in this reach of the Rio 

Grande. However, reservoir releases were not held 

constant. The ratios from regression analysis of 

downstream cross-sectional flow were 0.941 for 39 

summer irrigation season measurements and 0.943 for 

20 winter nonirrigation season measurements for this 

12.9-mile reach (table 3B). Total measured outflow in 

relation to total measured inflow for this reach for the 

summer and winter seasons is shown in figure 16. Total 

cross-sectional upstream inflows ranged from 321 to 

6,310 ft3/s for the irrigation season and from 344 to 

1,680 ft3/s for the nonirrigation season (table 3B). The 

mean-square errors of 9.3 to 9.6 percent, respectively, 

were smaller than errors determined for the BOR study 

because there was greater control of some of the flow 

factors previously discussed.

Weekly cross-sectional flow was measured at the 

Rio Grande near Bernalillo, Rio Grande at 

Albuquerque, and Rio Grande at Rio Bravo Bridge 

gaging stations during the winter nonirrigation season 

(December through February) from 1996 to 2000 

(current study). Reservoir releases were held constant 

except for two inadvertent releases. Flow loss could be 

more accurately estimated because flow was not 

measured during ice cover, during storms, or during the 

irrigation season, and evapotranspiration loss is much 

less in the winter. Two small wastewater-return flows 

from Rio Rancho near the Rio Grande near Bernalillo 

(upstream) gaging station were documented. The 

regression ratio of the Rio Grande at Rio Bravo Bridge 

(downstream) cross-sectional flow was 0.921 times the 

upstream cross-sectional flow for the 21.9-mile reach, 

and the mean-square error (6.5 percent) was much 

smaller than errors determined for Hansen (1995) and 

Thorn (1995) (table 3B) partly because the range of 

flow is much less. Cross-sectional inflow ranged from 

678 to 1,250 ft3/s for the regression equation. Total 

measured outflow in relation to total measured inflow 

for this reach for the winter nonirrigation season is 

shown in figure 17.

Flow Loss between Cross Sections and 

Daily Variation in Riverflow

For each succeeding paired cross-sectional flowmeasurement study, additional information was 

obtained to help control outside variables that could 

affect more accurate flow-loss measurements in the Rio 

Grande. The usefulness of daily gaging-station 

measurements, the measurements’ inherent accuracy, 

and the distance between gaging stations for 

meaningful flow differences also were determined. The 

regression equations estimating downstream from 

upstream cross-sectional flow had less error when more 

variables were controlled (table 3).
21
22 
23
24 

The increased accuracy of cross-sectional flow 

measurements also can be represented by the absolute 

daily mean change in flow at the Rio Grande at 

Albuquerque gaging station for 2 consecutive 

measurement days for the winter nonirrigation and 

summer irrigation seasons (fig. 18). The comparison of 

absolute change in riverflow represents reduction of the 

sources of flow variability and is probably the best 

indication of flow variability of the river during 

measurement days. Because flow changed between 

measurements during the first two studies, the loss 

calculated from the difference between upstream and 

downstream flow is not as accurate.

Another indication that provides an idea of flow 

loss between two sites is the differences in total flow 

between two cross sections regardless of any daily 

mean differences at adjacent gaging stations or 

measured cross-sectional differences at two sites. 

Paired losses calculated using this method, however, 

were extremely variable from measurement to 

measurement. Daily mean differences in flow represent 

all daily mean flow differences at the Rio Grande near 

Alameda, Rio Grande at Albuquerque, and Rio Grande 

at Rio Bravo Bridge gaging stations for the winter 

season compared to the distance between gaging 

stations (fig. 19). The differences between total inflow 

and total outflow between measurement cross sections 

for the summer irrigation and winter nonirrigation 

seasons are shown in figure 20 and listed in table 4.

The ratio of downstream total outflow to 

upstream inflow calculated from the slope of the 

regression equation subtracted from 1.00 represents the 

average flow loss as a portion of upstream flow of all 

the measurements. This technique uses all 

measurements to determine a flow-loss percentage, and 

this percentage can be used to estimate flow loss for a 

specific inflow discharge if it is within the range of 

measured inflows. These regression equation percent 

losses for summer irrigation and winter nonirrigation 

seasons in relation to distance between cross sections 

for all three flow-measurement studies are shown in 

figure 21. The median daily flow loss in relation to 

distance between cross sections is shown in figure 22. 

Both graphs show consistent flow loss per mile 

downstream and by season with allowance for nonideal 

river conditions for the initial measurement studies.

Flow loss for the current study (1996-2000) in 

relation to the change for 2 consecutive days of daily 

mean flow at the Rio Grande at Albuquerque gaging 

station is shown in figure 23. The individual paired 

measurement loss between the two cross sections (Rio 

Grande at Rio Bravo Bridge and Rio Grande near 

Bernalillo), for a steady-state river when the daily 

change is zero, is about 95 ft3

/s (fig. 23), which verifies 

the median loss of the paired measurements of 87.1 

ft3/s.

SUMMARY

The upper Rio Grande Basin, as defined by the 

U.S. Army Corps of Engineers, extends from the 

headwaters of the Rio Grande in southwestern 

Colorado to Fort Quitman, Texas. Most of the basin has 

a semiarid climate typical of the southwestern United 

States. This climate drives a highly variable streamflow 

regime that contributes to the complexity of water 

management in the basin. Currently, population growth 

in the basin has resulted in increasing demands on the 

hydrologic system. Water management decisions have 

become increasingly complex because of the broad 

range of interests and issues. For these reasons, the 

USGS, in cooperation with the City of Albuquerque, 

New Mexico, conducted paired flow measurements at 

two cross sections to determine cross-sectional loss in 

the Albuquerque reach of the Rio Grande.

Flow losses in the Albuquerque reach of the Rio 

Grande during the winter nonirrigation season from 

December 1996 to February 2000 and the two previous 

flow-loss investigations were statistically summarized. 

Daily mean flow losses are calculated during the winter 

nonirrigation season using daily mean flows at three 

selected Rio Grande streamflow-gaging stations.

During the winter nonirrigation season crosssectional measurements (1996-2000), an average of 

210 ft3

/s was returned to the river between the 

measurement sites, of which 165 ft3

/s was intercepted 

by riverside drains along the 21.9-mile reach from the 

Rio Grande near Bernalillo to the Rio Grande at Rio 

Bravo Bridge streamflow-gaging stations. The median 

total cross-sectional loss in this reach was 87.1 ft3

/s.

Regression equations were determined for 

estimating downstream total outflow from upstream 

total inflow for all three paired measurement studies. 

Regression equations relating the three daily mean flow 

gaging stations were determined. In each succeeding 

study, additional outside variables were controlled, 

which provided more accurate flow-loss 

measurements. Regression-equation losses between 

measurement cross sections ranged from 1.9 to 7.9 

percent during the nonirrigation season and from about 

5.9 to 6.4 percent during the irrigation season. 
25
26 
27 

(B) Estimated flow loss of the Rio Grande for three paired-measurement studies conducted from 1989 to 2000

Table 4. Estimated flow loss between cross sections on the Rio Grande in and near Albuquerque

[ft3/s, cubic feet per second]

(A) Estimated flow loss of the Rio Grande between the Rio Grande near Bernalillo and Rio Grande

at Rio Bravo Bridge streamflow-gaging stations, 1996-2000

Gaging-station name and

reach distance (fig. 2) Flow-loss regression (percent) Daily mean loss (ft3/s)

Rio Grande at Rio Bravo Bridge to Rio Grande at Albuquerque4.9 miles

Winter only

1.9

Median 7.5

Rio Grande at Albuquerque to Rio Grande near Alameda 8.0 miles

Winter only

5.1

Median 38.7

Rio Grande at Rio Bravo Bridge to Rio Grande near Alameda12.9 miles

Winter only

7.0

Median 51.8

Site or gaging-station name and

reach distance (fig. 2)

Season and 

number of 

measurements

Regression equation

flow loss (percent)

Individual measurement 

losses (ft3/s)

Isleta I-25 Bridge to Bernalillo Highway 44 Bridge32 miles

Summer 44

Winter 25

6.42.4

Median 297

Median 34.5

Rio Grande at Rio Bravo Bridge to Rio Grande near Alameda12.9 miles

Summer 38

Winter 20

5.95.7

Median 118

Median 39.4

Rio Grande at Rio Bravo Bridge to Rio Grande near Bernalillo21.9 miles

Winter 22 7.9 Median 87.1
28 
29
30 

Mean and median loss by reach length for all three 

daily mean flow stations and all three cross-sectional 

measurement reaches showed consistent flow loss per 

mile by season with allowance for nonideal river 

conditions for the initial measurement studies. 

Unsteady measurement conditions were reflected in the 

regression equation mean-square error and ultimately 

in the change in daily mean discharge at the Rio Grande 

at Albuquerque gaging station during the measurement 

period.

REFERENCES CITED

Hansen, Steve, 1995, 1994 paired-sample surface water 

budget for the Middle Rio Grande–Albuquerque reach: 

Bureau of Reclamation, Final draft copy.

Thorn, C.R., 1995, Surface-water discharge and 

evapotranspiration rates for grass and bare soil along a 

reach of the Rio Grande, Albuquerque, New Mexico, 

1989-95: U.S. Geological Survey Open-File Report 95-

419, 23 p.

Waltemeyer, S.D., 1994, Traveltime and reaeration 

characteristics for a reach of the Rio Grande, 

Albuquerque, New Mexico, October 1991: U.S. 

Geological Survey Water-Resources Investigations 

Report 94-4071, 19 p.