Data Series 255

U.S. Department of the Interior

U.S. Geological Survey

In cooperation with the Texas Commission on Environmental Quality

Water-Quality and Ancillary Data Collected 

From the Arroyo Colorado Near 

Rio Hondo, Texas, 2006
Cover. Arroyo Colorado downstream from Rio Hondo lift bridge, June 2005 (photograph courtesy of Roger Miranda, Texas 

Commission on Environmental Quality).
Water-Quality and Ancillary Data Collected 

From the Arroyo Colorado Near 

Rio Hondo, Texas, 2006

By Meghan C. Roussel, Michael G. Canova, William H. Asquith, and 

Richard L. Kiesling 

U.S. Department of the Interior

U.S. Geological Survey

In cooperation with the Texas Commission on Environmental Quality

Data Series 255
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia: 2007

For more information about the USGS and its products:

Telephone: 1-888-ASK-USGS

World Wide Web: http://www.usgs.gov/

Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply 

endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual copyright owners to 

reproduce any copyrighted materials contained within this report.

Suggested citation:

Roussel, M.C., Canova, M.G., Asquith, W.H., and Kiesling, R.L., 2007, Water-quality and ancillary data 

collected from the Arroyo Colorado near Rio Hondo, Texas, 2006: U.S. Geological Survey Data Series 255, 

46 p.
 iii

Contents

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

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

Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Description of Study Area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Methods of Investigation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Site Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Sampling/Monitoring and Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Algal Productivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Continuous Water-Quality Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Sedimentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Discrete Samples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Algal Growth and Mortality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Bioassay Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Phytoplankton and Zooplankton Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Vertical Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Data Treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Water-Quality and Ancillary Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Appendix 1—Data collected at near-bottom and near-surface depths of the Arroyo Colorado near 

Rio Hondo, Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

1–1.1—1–1.4. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, 

Texas, using: 

1–1.1. Algal productivity methods (5 feet below water surface) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1–1.2. Multiparameter continuous water-quality monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1–1.3. Sediment traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

1–1.4. Environmental discrete-sample analysis: 

1–1.4.a. February 2006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

1–1.4.b. May 2006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

1–2.1—1–2.4. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, 

Texas, using: 

1–2.1. Algal productivity methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

1–2.2. Multiparameter continuous water-quality monitors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

1–2.3. Algal growth and mortality analyses: 

1–2.3.a. Bioassay analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

1–2.3.b. Phytoplankton analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

1–2.3.c. Zooplankton analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

1–2.4. Environmental discrete-sample analysis: 

1–2.4.a. February 2006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

1–2.4.b. May 2006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

1–3. Data collected for quality assurance/quality control from the Arroyo Colorado near Rio 

Hondo, Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
iv 

Appendix 2—Vertical profile data collected from the Arroyo Colorado near Rio Hondo, Texas . . . . . . . . . . . . . . 39

2–1. Water-quality monitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

2–2. PAR sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Figures

1–2. Maps showing: 

1. Arroyo Colorado Basin, Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2. Water-quality data-collection sites on the tidal segment (2201) of the Arroyo Colorado, 

Texas, February and May 2006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3. Schematic diagram of water-quality data collection in the tidal segment (2201) of the Arroyo 

Colorado, Texas, February and May 2006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4–7. Photographs showing: 

4. Light-dark bottle experiment being deployed in the Arroyo Colorado near Rio Hondo, 

Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5. Continuous multiparameter water-quality monitor configuration and deployment in 

the Arroyo Colorado near Rio Hondo, Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6. Sediment trap deployment in the Arroyo Colorado near Rio Hondo, Texas . . . . . . . . . . . . . . . . . . . 7

7. Near-bottom water being collected using the Kemmerer sampler in the Arroyo 

Colorado near Rio Hondo, Texas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Tables

1. Water-quality data-collection sites on the tidal segment (2201) of the Arroyo Colorado, 

Texas, February and May 2006 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2. Physical characteristics with measurement methods specified by the Texas Commission 

on Environmental Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3. Analytes with measurement methods specified by Texas Commission on Environmental 

Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Datum

Horizontal coordinate information is referenced to North American Datum of 1983 (NAD 83).
Water-Quality and Ancillary Data Collected 

From the Arroyo Colorado Near 

Rio Hondo, Texas, 2006

By Meghan C. Roussel, Michael G. Canova, William H. Asquith, and Richard L. Kiesling

Abstract

The Arroyo Colorado is in the lower Rio Grande Valley of 

southern Texas and extends from near Mission, Texas, eastward 

to the Laguna Madre estuarine and coastal marine system, 

which separates Padre Island from the Texas mainland. Streamflow in the Arroyo Colorado primarily is sustained by effluent 

from municipal wastewater-treatment plants along the stream 

banks. Since 1986, the tidal segment of the Arroyo Colorado 

from the port of Harlingen to the Laguna Madre has been designated by the State of Texas as an impaired water body because 

of low dissolved oxygen concentrations. Efforts to develop predictive water-quality models for the tidal segment of the Arroyo 

Colorado have been hampered by a lack of physical, biological, 

and biochemical data. Specifically, data on primary algal productivity, nutrient cycling, sediment deposition rates, and the 

relations between these processes and dissolved oxygen dynamics in the stream have been inadequate to support water-quality 

modeling efforts. The U.S. Geological Survey, in cooperation 

with the Texas Commission on Environmental Quality, did a 

study in 2006 to collect data associated with primary algal productivity, nutrient cycling, and dissolved oxygen dynamics in 

the tidal segment (2201) of the Arroyo Colorado near Rio 

Hondo. Specific objectives of the study were to (1) characterize 

water quality by measuring basic properties; (2) characterize 

the concentrations of carbon and nutrients, biochemical oxygen 

demand, total organic carbon, total suspended solids, and volatile suspended solids; (3) measure the seasonal differences of 

nutrient-dependent algal growth and algal production in the 

water column; (4) measure oxygen respiration or production 

rates; and (5) measure rates of sediment deposition.

Introduction

The Arroyo Colorado is in the lower Rio Grande Valley of 

southern Texas and extends from near Mission, Tex., eastward 

to the Laguna Madre estuarine and coastal marine system, 

which separates South Padre Island from the Texas mainland 

(fig. 1). Streamflow in the Arroyo Colorado primarily is sustained by effluent from municipal wastewater-treatment plants 

along the stream banks. Additional streamflow is contributed by 

irrigation return flow, storm runoff, and other sources. The 

Arroyo Colorado is used as a floodway; an inland waterway; 

and a recreational area for boating, fishing, and swimming; and 

is an important nursery and foraging area for crab, shrimp, and 

several types of marine fish (Raines and Miranda, 2002). 

The Texas Commission on Environmental Quality 

(TCEQ) has classified two distinct stream sections (fig. 1) of 

the Arroyo Colorado (Texas Natural Resource Conservation 

Commission, 1997) on the basis of the physical characteristics 

of the stream. Segment 2201 extends downstream from the 

port of Harlingen to the Laguna Madre at the border of Cameron 

and Willacy Counties, is tidally influenced, provides habitat 

to a diverse range of aquatic organisms, and has contactrecreational and high aquatic life designated uses. Segment 

2202 extends upstream from the port of Harlingen to Perezville 

in Hidalgo County, is nontidal, is the shallower and narrower of 

the two segments, and also has contact-recreational and intermediate aquatic life designated uses. Segment 2202 is not considered further in this report.

Since 1986, the tidal segment of the Arroyo Colorado has 

been designated by the State of Texas as an impaired water 

body because of low dissolved oxygen (DO) concentrations 

(R.M. Miranda, Texas Commission on Environmental Quality, 

oral commun., 2005). Efforts to develop predictive waterquality models for the Arroyo Colorado have been hampered by 

a lack of physical, biological, and biochemical data. These data 

are necessary to provide information on primary algal productivity, nutrient cycling, sediment deposition rates, and the relations between these processes and DO dynamics used to support 

many types of water-quality models. The catalyst for the investigation described here was the need for more data to increase 

the reliability of predictive models.

The U.S. Geological Survey (USGS), in cooperation with 

the TCEQ, did a study in 2006 to collect data associated with 

primary algal productivity, nutrient cycling and DO dynamics 

in the tidal segment (2201) of the Arroyo Colorado near Rio 

Hondo. Specific objectives of the study were to (1) characterize 
2 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

water quality by measuring 15-minute values of DO, pH, specific conductance, and temperature at two depths (near bottom 

and near surface) for each of four sites in the tidal segment over 

a 24-hour or longer period during one data-collection period in 

February 2006 and one in May 2006; (2) characterize the concentrations of carbon and nutrients (including pertinent nitrogen 

and phosphorus species), biochemical oxygen demand (BOD), 

total organic carbon (TOC), total suspended solids (TSS), 

and volatile suspended solids (VSS) during the two periods; 

(3) measure the seasonal (as provided by data from the two collection periods) differences of nutrient-dependent algal growth 

and algal productivity in the water column; (4) measure oxygen 

respiration or production rates; and (5) measure rates of sediment deposition during each of the two data-collection periods. 

Purpose and Scope

The purpose of this report is to describe the methods for 

data sampling and analysis and to present the water-quality 

and ancillary data collected in the tidal segment (2201) of 

the Arroyo Colorado near Rio Hondo, Tex., during two datacollection periods, one in February and one in May 2006. 

Site selection, sampling/monitoring and analysis, and postcollection data treatment, including quality assurance/quality 

control (QA/QC), are described. The data (in tabular format) are 

presented in two appendixes, one containing the data collected 

at near-bottom and near-surface depths and one containing the 

data collected along vertical profiles.

Description of Study Area

The study area is in southern Texas in the lower Rio 

Grande Valley (fig. 1). The Arroyo Colorado flows about 

90 miles from west to east and has a contributing drainage area 

(basin) of about 700 square miles. The study area is in the 

neotropical Southern Coastal Plain physiographic province 

(National Oceanic and Atmospheric Administration, 1996) and 

is characterized by long, hot summers and short, mild winters. 

The mean annual temperature is about 73 degrees Fahrenheit 

(°F), and mean monthly temperatures range from 58 °F (January) to 84 °F (July). Mean annual evaporation in the study area 

is about 58 inches. Mean annual rainfall is about 21 inches at the 

western limit and 27 inches at the eastern limit of the study area. 

Base from U.S. Geological Survey digital data, 1:100,000

Universal Transverse Mercator projection

Zone 14

ARROYO COLORADO BASIN

Segment 2202 Segment 2201

HIDALGO

WILLACY

CAMERON UNITED STA

MEXICO

TES

TEXAS

LOCATION MAP

Area enlarged

0 10 5 MILES

LAGUNA MADRE

GULF OF MEXICO

RIO GRANDE

Arroyo Colorado

Cayo Atascoso

North Floodway Elsa

Donna Alamo

Pharr

Alton

Lyford

Hidalgo

Bayview

Weslaco

Primera Mission

Penitas

La Joya La Homa

Edcouch

Progreso

La Feria

Mercedes

San Juan

Palmview McAllen

Edinburg

Mila Doce

Harlingen

Rio Hondo

Sebastian

San Benito

Lopezville

Perezville

Santa Rosa

Brownsville

Port Isabel Indian Lake

Los Fresnos

Rangerville

Palm Valley

Rancho Viejo

Laguna Vista

Raymondville

Progreso Lakes

South Padre

 Island

98 30' 98 97 30'

26 30'

Port of Harlingen 26

Area enlarged in figure 2

Figure 1. Arroyo Colorado Basin, Texas (modified from Raines and Miranda, 2002, fig. 1).
Methods of Investigation 3

UV345

Sam Hou

ston

FM 106

Williams

Colorado

Combes Rio Hondo

Fernando East

Reynolds

Madero

08470450 (13074)

08470500 (13072)

08470460 (16142)

08470520 (13073)

08470450 (13074)

Valley Intl

012 0.5 MILES

Rio

Hondo

97 37'30"W 97 35'0"W 97 32'30"W

26 12'30"N 26 15'0"N

Reach 2

Reach 1

EXPLANATION

2202

2201

Lift

Bridge

Base map: StreetMap USA roads, railroads, and landmarks.

USGS National Hydrography Dataset 1:24,000 Hydrology

Geographic projection, North American Datum 1983

Water-quality data-collection site—

Identified by USGS station number

(TCEQ station number)

Figure 2. Water-quality data-collection sites on the tidal segment (2201) of the Arroyo Colorado, Texas, February and May 2006.

The lower Rio Grande Valley has flat terrain and is extensively cultivated and irrigated for agriculture. Water for irrigation is transported from the Rio Grande through canals to the 

fields by operators of numerous irrigation districts. The irrigation districts provide water for irrigation of citrus, sugar cane, 

and several row crops that include corn, grain sorghum, and cotton. Irrigation practices generally consist of periodic field 

flooding during periods of insufficient rainfall to produce economically viable crop yields. Urban development is extensive 

in many areas adjacent to the Arroyo Colorado, particularly in 

the western and central parts of the drainage area. 

There are 21 permitted dischargers in the Arroyo Colorado 

Basin: 16 are municipal wastewater-treatment plants, three are 

industrial, and two are shrimp farm operations. The limits of the 

municipal discharge permits range from 0.4 to 10 million gallons per day (Raines and Miranda, 2002). 

Acknowledgments

The authors recognize the contributions of Roger Miranda, 

TCEQ Total Maximum Daily Load (TMDL) Project Manager, 

and Faith Hambleton, TCEQ TMDL Program Manager.

Methods of Investigation

Site Selection

Two reaches, each of which is bounded by two sampling 

sites within segment 2201, were specified by TCEQ as areas of 

particular interest (fig. 2; table 1). Site selection was based on 

the requirements of the TCEQ TMDL program (R.M. Miranda, 

Texas Commission on Environmental Quality, oral commun., 
4 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

2005). The first reach is between USGS stations 08470450 and 

08470460, near the boundary between the tidal and nontidal 

segments of the Arroyo Colorado, and the second reach is 

between USGS stations 08470500 and 08470520, downstream 

of the lift bridge on FM 106 in Rio Hondo, where summer 

fish kills are common (R.M. Miranda, Texas Commission on 

Environmental Quality, oral commun., 2005). The sites provide 

potential calibration points for modeling and other assessments. 

Table 1. Water-quality data-collection sites on the tidal segment 

(2201) of the Arroyo Colorado, Texas, February and May 2006. 

[USGS, U.S. Geological Survey; TCEQ, Texas Commission on Environmental 

Quality] 

Sampling/Monitoring and Analysis

Because of the tidal nature of the segment, two depths 

(near bottom and near surface) at each of the four selected sites 

were designated for sampling. A schematic diagram of waterquality sampling for each data-collection period, one in February 2006 and one in May 2006, is shown in figure 3. For nearbottom depths at each site, algal productivity measurements 

were taken (using light-dark bottle experiments), multiparameter water-quality monitors were deployed, sediment traps (to 

measure sedimentation rates) were deployed, and discrete environmental samples were collected. For near-surface depths at 

each site, algal productivity measurements were taken, multiparameter water-quality monitors were deployed, water samples for bioassay analysis were collected, water samples for 

phytoplankton and zooplankton analysis were collected, and 

discrete environmental samples were collected. Also at each 

site, vertical profiles of water-quality characteristics and photosynthetically active radiation (PAR) were conducted as well 

as a variety of field measurements. QA/QC samples were collected at selected sites. Physical characteristics (from field 

measurements) and respective measurement methods specified 

by TCEQ are listed in table 2, and analytes (from environmental 

samples) and respective measurement methods specified by 

TCEQ are listed in table 3. All other data collected were analyzed using standard USGS methods.

USGS

station

no.

TCEQ 

station

no.

Station name

Latitude

(decimal

degrees)

Longitude

(decimal

degrees)

08470450 13074 Arroyo Colorado above 

Rio Hondo, Texas

26.195 97.602

08470460 16142 Arroyo Colorado at the 

port of Harlingen, Rio 

Hondo, Texas

26.203 97.596

08470500 13072 Arroyo Colorado at FM 

106 at Rio Hondo, 

Texas

26.235 97.584

08470520 13073 Arroyo Colorado at 

Camp Perry near Rio 

Hondo, Texas

26.265 97.583

Table 2. Physical characteristics with measurement methods specified by Texas Commission on Environmental Quality. 

[TCEQ SOP, Texas Commission on Environmental Quality (2003) Standard Operating Procedure; EPA, U.S. Environmental Protection Agency (1983); mg/L, 

milligrams per liter; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; μE/m2/sec, microEinsteins per square meter per second; ppt, 

parts per thousand; SM, Standard Method (American Public Health Association, 1998); ft/sec, feet per second; FNMU, formazin nephelometric units] 

Physical characteristic Units Method

Depth feet TCEQ SOP

pH pH units EPA 150.1 and TCEQ SOP

Dissolved oxygen mg/L EPA 150.1 and TCEQ SOP

Specific conductance μS/cm EPA 150.1 and TCEQ SOP

Temperature °C EPA 150.1 and TCEQ SOP

Secchi depth feet TCEQ SOP

Light μE/m2/sec Wetzel and Likens (1979)

Days since significant rainfall days TCEQ SOP

Salinity ppt SM 2520 and TCEQ SOP

Velocity ft/sec TCEQ SOP

Air temperature °C TCEQ SOP

Turbidity FNMU EPA 160.1
Methods of Investigation 5

Bioassay Phytop/Zoop 

DAY

SITE

NEAR

BOTTOM

NEAR

SURFACE

Continuous

Water-quality

monitor profiles

productivity

Sedimentation

pH DO Specific QA/QC

PAR sensor

profiles

Temperature pH DO Specific Turbidity Salinity cond.

cond. Env.

Abbreviations:

DO—dissolved oxygen

cond.—conductance

env.—environmental

QA/QC—quality assurance/quality 

control

PAR—photosynthetically active 

radiation

Phytop/zoop—phytoplankton/

zooplankton

Temperature

Blank Replicate

Algal

productivity samples

pH DO Specific QA/QC cond. Temperature Env.

Blank Replicate

Algal Discrete

samples

Discrete water-quality 

monitoring

profile

Vertical

Continuous

water-quality 

monitoring

Algal growth

and mortality

analysis analysis

Figure 3. Schematic diagram of water-quality data collection in the tidal segment of the Arroyo Colorado, Texas, February and May 

2006.

Water samples collected at the four sites during each of the 

two data-collection periods were analyzed for a suite of waterquality constituents that included 5-day BOD, chloride and sulfate, chlorophyll a and pheophytin a, nutrients, particulate carbon and particulate nitrogen, and TSS and VSS. In addition, 

bioassay analyses, sediment flux measurements, and standing 

light-dark bottle productivity measurements were made. Field 

measurements consisted of air temperature, barometric pressure, Secchi depth, wind speed, and vertical profile data that 

comprised DO, PAR, pH, salinity, specific conductance, turbidity, and water temperature. The scope of work did not include 

measurements of streamflow.

Algal Productivity

Algal productivity measurements, which describe watercolumn primary productivity and are determined by changes in 

DO concentrations using light-dark bottle methods, were taken 

at one site per reach (two sites total) at near-surface (about 1 

foot below the water surface) and near-bottom (about 5 feet 

below the water surface) depths. DO and temperature profiles 

were measured in-situ at each site. These measurements were 

used as initial conditions with which to compare the final values 

obtained from the light-dark bottle experiments. A replicate set 

(two each) of clear and dark plastic-coated bottles were filled 

with water collected at the two specified depths and sealed with 

standard ground-glass stoppers to prevent gas exchange with 

the surrounding water column. Care was taken to shade the bottles during the filling process. Once all the bottles were filled, 

they were secured to a bottle rack (as shown in fig. 4) and suspended at the depth from which the water was collected. After 

a minimum of 4 hours of deployment, the light-dark bottles 

were removed from the water column, and DO and temperature 

measurements were made. Reaeration was kept to a minimum 

during final DO and temperature measurements. Start and end 

times for the instream incubations were recorded, as were DO 

and temperature measurements. 
6 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Table 3. Analytes with measurement methods specified by Texas 

Commission on Environmental Quality. 

[mg/L, milligrams per liter; EPA, U.S. Environmental Protection Agency 

(1983); N, nitrogen; P, phosphorus; μg/L, micrograms per liter; SM, Standard 

Method (American Public Health Association, 1998); cells/mL, cells per milliliter; ind./mL, individuals per milliliter] 

Analyte Units Method

Total suspended solids mg/L EPA 160.2

Total organic carbon mg/L EPA 415.1

Dissolved organic 

carbon

mg/L EPA 415.2

Total dissolved solids mg/L EPA 160.1

Sulfate mg/L EPA 300.0

Chloride mg/L EPA 300.0

Ammonia-nitrogen, 

total

mg/L as N EPA 350.1

Orthophosphate, 

dissolved

mg/L as P EPA 365.1

Total reactive phosphate mg/L EPA 365.1

Total phosphorus wet 

method

mg/L as P EPA 365.1

Nitrate/nitrite-nitrogen, 

total

mg/L as N EPA 353.2

Total kjeldahl nitrogen mg/L as N EPA 351.2

Total nitrogen mg/L as N Computation

Chlorophyll a μg/L SM 10200 H

Pheophytin a μg/L SM 10200 H

Phytoplankton cells/mL SM 10200 F

Zooplankton ind./mL SM 10200 G

Particulate carbon mg/L EPA 440.0

Particulate nitrogen mg/L EPA 440.0

5-day biochemical 

oxygen demand

mg/L SM 5210

Volatile suspended 

solids

mg/L EPA 160.4

Algal productivity mg/L SM 10300D2

Algal growth day-1 Lehman and Sandgren (1985)

Algal mortality day-1 Lehman and Sandgren (1985)

Figure 4. Light-dark bottle experiment being deployed in the 

Arroyo Colorado near Rio Hondo, Texas. 

Standard light-dark bottle computational methods were 

used to determine gross primary productivity (GPP) and net primary productivity (NPP) or gross respiration and net respiration, where respiration is signified by a negative value, for each 

site at each of the two depths (American Public Health Association, 1998). GPP is computed by subtracting the final DO concentration in the dark bottle (DB) from the final DO concentration in the light bottle (LB) and then dividing by the incubation 

period ( ) and a conversion factor to convert liters to cubic 

meters (milligrams of oxygen/cubic meter/day). The equation 

for GPP is as follows:

. (1)

NPP (summation of all metabolic processes) is computed 

by subtracting the initial light bottle DO concentration (ILB) 

from the final DO concentration in the light bottle (LB) and then 

dividing by the incubation period ( ) and a conversion factor 

to convert liters to cubic meters. The equation for NPP is as follows:

. (2)

In this method, changes in the mass of oxygen in the closed 

bottles during the incubation period are used to estimate rates of 

primary productivity. In this study, one replicate in addition to 

the environmental sample at each depth allowed for an averaging of the computed rates. Procedures follow those outlined in 

method 10300D2 of “Standard Methods for the Examination of 

Water and Wastewater” (American Public Health Association, 

1998). 

Continuous Water-Quality Monitoring

Multiparameter water-quality monitors were deployed at 

the near-surface and near-bottom depths at all four sites to collect 15-minute DO, pH, specific conductance, and temperature 

data. The instruments were deployed for a minimum of 24 hours 

during concurrent collection of other data. The monitor configuration and deployment procedure are shown in figure 5. 

Procedures for 24-hour continuous multiparameter field data 

collection follow standard protocols (Texas Commission on 

Environmental Quality, 2003; U.S. Geological Survey, 2006).

Sedimentation

Sedimentation is the vertical deposition of mass per unit 

time per unit area (mass flux) in the water column. Sedimentation is of critical importance to estimates of sediment movement 

and algal mortality within the context of water-quality models. 

Sedimentation represents the transport of particulate chemical 

species vertically through the water column with the explicit 

assumption that the chemical species reach the sediments. Sediment traps are used to measure the deposition of particulates 

over a specified period of time by integrating particle deposition 

Δt

GPP ( ) LB DB –

Δt = --------------------------- × 1000

Δt

NPP ( ) LB ILB –

Δt = ---------------------------- × 1000
Methods of Investigation 7

through time in a collection cylinder. The traps are cylindrical 

collectors closed at the bottom and open at the top that catch 

mineral particles, plant debris, refractory organic material, dead 

phytoplankton and zooplankton, the feces of zooplankton and 

fish, and other detritus. The traps are attached to a line with 

floats on the surface and a weight at the bottom to keep the trap 

vertical. 

At each site, 4-inch-diameter traps were deployed in pairs 

(fig. 6). After a specified period of time, approximately 48 

hours for this study, the traps were recovered. The exact time of 

deployment and retrieval were noted for each trap to allow for 

the computation of a flux. For retrieval, traps were pulled to the 

surface, ensuring the cylindrical collectors remained vertical; 

the cylinders then were emptied into 9-liter carboys. The collected material was weighed and analyzed for TSS and VSS 

and, during the February data-collection period, particulate carbon and nitrogen. The mass of collected material divided by the 

collection area and the deployment time of the traps yields the 

sedimentation flux. Sediment traps were deployed during each 

of the two data-collection periods at all four sites. 

Figure 5. Continuous multiparameter water-quality monitor configuration and deployment in the Arroyo Colorado near Rio Hondo, 

Texas. 

Figure 6. Sediment trap deployment in the Arroyo Colorado 

near Rio Hondo, Texas.

Discrete Samples

The USGS collected water samples in the tidal segment of 

the Arroyo Colorado during each of the two data-collection 

periods to identify seasonal differences in water quality. Samples were collected on 2 consecutive days at near-surface and 

near-bottom depths at the four sites. Near-surface samples were 

collected by the grab-sample method—direct filling of sample 

bottles from a boat. Near-bottom water samples were collected 

using a Kemmerer sampler as shown in figure 7. The Kemmerer 

sampler consists of a hollow cylinder with remotely activated 

stoppers at each end activated by a weighted messenger. Samples requiring field filtration were filtered in environmental 

chambers, made up of clear polyethylene bags supported by 

plastic frames, to minimize the potential for contamination. 

Equipment that came into contact with the sample was rinsed 

three times with deionized water between use at each sampling 

site. The different sampling methods used for sampling nearsurface (grab sample) and near-bottom (Kemmerer sampler) 

water prevented contamination between samples at each site.

Figure 7. Near-bottom water being collected using the 

Kemmerer sampler in the Arroyo Colorado near Rio Hondo, Texas. 
8 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Algal Growth and Mortality

Bioassay Analysis

Algal population growth was determined using standard 

nutrient-addition bioassays (Lehman and Sandgren, 1985). Bioassay analyses were conducted in the laboratory under ambient 

temperature and light conditions on water samples collected at 

each of the four sites at near-surface depths. Water was transported to the laboratory and allocated to one of four treatment 

groups: control, phosphate (PO4) addition, nitrate (NO3) addition, or combined PO4+NO3 addition. Each treatment consisted 

of four cultures that were monitored for growth every other day 

for 10 days. Zooplankton were removed from the bioassay 

water using a 153-micrometer-mesh sieve. Changes in algal 

biomass were measured using an acclimated growth-rate 

method where algal populations are measured using in-vivo 

fluorescence (IVF). An exponential growth model was fit to the 

IVF data for each culture, providing four estimates of algal population growth rate per treatment per site. Growth rates were 

used to determine where nutrient additions appreciably 

enhanced algal growth. Nutrient addition and dilution bioassays 

were used to simultaneously estimate algal growth rates and 

grazing mortality rates following the methods of Lehman and 

Sandgren (1985).

Algal mortality rates were determined using experimental 

grazer density gradients. Zooplankton were collected from the 

Arroyo Colorado at each site and were used to increase animal 

density to ambient levels observed in the field. Micro-grazers 

also were manipulated through the use of dilution of ambient 

water using particle-free Arroyo Colorado water. Any observed 

negative changes in algal growth rates were attributed to the 

density of grazers in the experimental treatments. Algal mortality rates were assumed to be equal to these negative growth 

rates. 

Phytoplankton and Zooplankton Analysis

Preserved phytoplankton samples and preserved zooplankton samples were used to estimate ambient population densities 

at all four sites. Phytoplankton cell counts and zooplankton animal counts were determined for each water sample during the 

two data-collection periods and were identified to the lowest 

possible taxonomic level. 

Vertical Profiles

At the same time samples were collected at near-bottom 

and near-surface depths, vertical profiles of DO, pH, salinity, 

specific conductance, turbidity, and water temperature were 

measured at intervals of 1 foot with a multiparameter waterquality monitor. In addition, PAR-sensor profiles, a measure of 

upwelling and downwelling radiation in a water column 

between wavelengths of 400 and 700 nanometers, were done in 

conjunction with the light-dark bottle experiments. Measurements were taken in the air, just above the water surface, at the 

surface of the water with the sensors just under the water, and 

then at 1-meter intervals down through the water column. PARsensor measurements in the air were taken to provide an idea of 

ambient light conditions. The PAR-sensor profiles provide a 

measurement of sunlight intensity at a specified point in the 

water column looking toward the water surface (downwelling) 

and looking toward the streambed (upwelling). Sunlight intensity influences biota in the water column that rely on photosynthesis for growth.

Data Treatment

Severn Trent Labs (STL) in Denver, Colo., analyzed most 

of the constituents, except for chlorophyll a and pheophytin a,

which were analyzed by STL in Westfield, Mass., and particulate carbon and particulate nitrogen, which were analyzed by an 

STL subcontractor, Nutrient Analytical Services Laboratory, 

Chesapeake Biological Laboratory in Solomons, Md. Biological analyses were done by USGS laboratory staff, except for 

phytoplankton analyses, which were done by the Department of 

Biology and Center for Subtropical Studies, University of 

Texas–Pan American, Edinburg, Tex. 

Environmental sample data were subject to two reviews. 

Data were initially reviewed by the Contracting Officer’s Representative for the USGS analytical-services contract with STL. 

The focus of this review was to determine the completeness of 

the samples analyzed, if holding times were met, if dilution factors were applied, and if QA/QC samples were within acceptance criteria. The final data review was done by a designated 

USGS Data Manager before data were entered into the USGS 

National Water Information System (NWIS) (U.S. Geological 

Survey, 2001). The focus of the review was to verify the accuracy and completeness of the laboratory data, to determine if 

laboratory QA/QC data had any effect on the results, and to 

determine whether samples were handled appropriately in the 

field and the laboratory.

Field measurements, such as DO, pH, specific conductance, temperature, and turbidity were reviewed by verifying 

that the standards used for calibration were adequate, the postcalibration checks were within calibration criteria, and the 

results were consistent between multiple measurements of the 

same constituent. The field measured physical characteristics 

were measured multiple times during instantaneous measurements, vertical profile measurements, and 24-hour continuous 

monitoring. 

Field analyses consisted of BOD determinations and 

water-column primary productivity measurements (light-dark 

bottle experiment) (U.S. Geological Survey, 2006). Replicate 

sample analysis was used to determine the variability of the 

results. BOD data were qualified in accordance with standard 

USGS methods (U.S. Geological Survey, 2006).

The field QA/QC samples collected were field blanks and 

field replicates (two each). Field blanks were used to check for 

sample contamination in the field by analyzing inorganics-free 

water that was exposed to the field-sampling equipment used to 
Water-Quality and Ancillary Data 9

collect and process environmental samples. Field replicates 

were used to assess the variability of sample handling, preservation, and storage. QA/QC sample results are in appendix 1, 

table 1–3. 

Data were combined into sample sets organized by site, 

date, and time following the review process described above. 

The sample sets were entered into the USGS NWIS, and chemical verification checks were done and used to evaluate each 

sample set. Chemical verification checks are these: Total constituents concentration must be greater than dissolved constituents concentration, mass ion-balance ratios must be within 

specified limits of ±5.49 percent difference, and the ratio of the 

sum of constituents to specific conductance must be within 

specified limits of 0.55 to 0.81. The final sample sets were 

checked for transcription and typographical errors.

Finally, data were qualified using “value qualifier codes.” 

Value qualifier codes are used to describe a sample result that 

does not meet QA/QC criteria or to give additional information 

about how the sample was treated or the analysis was done. The 

following codes are used: sample diluted (d), value verified by 

rerun same method (r), sample received warm (*), holding time 

exceeded (@), and analyte detected in laboratory blank (v). The 

potential effect of the assignment of the value qualifier code 

was judged by the USGS Data Manager, and subsequently, a 

“remark code” was assigned. Samples were assigned a remark 

code of “less than” (<) if the results were below the laboratory 

reporting limit. Samples were assigned a remark code of 

“estimated” (E) if the data values are uncertain because of the 

deficiencies noted by the value qualifier code(s). For this report, 

remark codes only are included in the data tables. The value 

qualifier codes are available in the NWIS database.

Water-Quality and Ancillary Data

Data are grouped into two appendixes at the end of this 

report: (1) data collected at the near-surface and near-bottom 

depths of the Arroyo Colorado and (2) vertical profile data collected in the Arroyo Colorado. Data collected at near-bottom 

depth of the Arroyo Colorado are listed in the following order 

(appendixes 1–1.1 through 1–1.4): algal productivity measurements, continuous water-quality monitor measurements, sedimentation measurements, and discrete sample results. Data 

collected at near-surface depth of the Arroyo Colorado are 

listed in the following order (appendixes 1–2.1 through 1–2.4): 

algal productivity measurements, continuous water-quality 

monitor measurements, algal growth and mortality analyses 

(bioassay analysis, phytoplankton analysis, zooplankton 

analysis), and discrete sample results. Discrete sample results 

(appendixes 1–1.4 and 1–2.4) are categorized by data-collection 

period. Data collected for QA/QC purposes are listed in appendix 1–3. Water-quality vertical profile data are listed in appendix 2–1, and the PAR sensor vertical profile data are listed in 

appendix 2–2.

Water-quality data shown in this report allow specific 

comparisons between the two depths for each of the four sites 

sampled in the tidal segment of the Arroyo Colorado during the 

February and May 2006 data-collection periods. Finally, the 

water-quality data facilitate general analyses of the productivity, biochemical oxygen dynamics, and nutrient cycling in the 

tidal segment of the Arroyo Colorado, Texas.

References

American Public Health Association, 1998, Standard methods 

for the examination of water and wastewater (20th ed.): 

American Public Health Association, United Book Press, 

1,220 p.

Lehman, J.T., and Sandgren, C.D., 1985, Species-specific rates 

of growth and grazing loss among freshwater algae: Limnology Oceanography, v. 30, p. 34–46.

National Oceanic and Atmospheric Administration, 1996, Climatological data, Texas, annual summary: Asheville, N.C., 

U.S. Department of Commerce, v. 101, no. 13, 77 p.

Raines, T.H., and Miranda, R.M., 2002, Simulation of flow and 

water quality of the Arroyo Colorado, Texas, 1989–99: U.S. 

Geological Survey Water-Resources Investigations Report 

02–4110, 56 p.

Texas Commission on Environmental Quality, 2003, Surface 

water quality monitoring procedures, Volume 1—Physical 

and chemical monitoring methods for water, sediment and 

tissue: Texas Commission on Environmental Quality, 

RG–415 [variously paged].

Texas Natural Resource Conservation Commission, 1997, 

Texas surface-water-quality standards: Texas Natural 

Resource Conservation Commission, chap. 307.1–307.10, 

125 p.

Wetzel, R.G., and Likens, G.E., 1979, Limnological analyses: 

Philadelphia, W.B. Saunders Co., 429 p.

U.S. Environmental Protection Agency, 1983, Methods for 

chemical analysis of water and wastes: U.S. Environmental 

Protection Agency Report EPA/600/4–79/020.

U.S. Geological Survey, 2001, National Water Information 

System (NWISWeb) data available on the World Wide 

Web, accessed January–September 2006 at 

http://waterdata.usgs.gov/nwis/.

U.S. Geological Survey, 2006, National field manual for the 

collection of water-quality data: U.S. Geological Survey 

Techniques of Water-Resources Investigations, book 9, 

chaps. A1–A9, accessed January–September 2006 at 

http://pubs.water.usgs.gov/twri9A 
Blank Page
Appendix 1

Appendix 1—Data Collected at Near-Bottom 

and Near-Surface Depths of the Arroyo Colorado 

Near Rio Hondo, Texas 
Blank Page
Appendix 1 13

Appendix 1–1.1. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using algal productivity methods 

(5 feet below water surface).

[mg O2/m3/day, milligrams of oxygen per cubic meter per day; negative value signifies deficit of oxygen and positive value signifies accumulation of oxygen]

USGS

station no. Date

Datacollection

period

Gross primary

productivity

(mg O2/m3

/day)

 Net primary

productivity 

(mg O2/m3

/day)

Respiration

(mg O2/m3

/day)

08470460 02/22/2006 February 568 -2,309 2,878

08470460 05/23/2006 May 2,626 -5,082 7,708

08470500 02/22/2006 February 51 -5,788 5,839

08470500 05/23/2006 May 11,560 9,560 2,400

Appendix 1–1.2. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors.

[°C, degrees Celsius; μS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L, milligrams per liter. Dissolved oxygen values less than 2.0 mg/L reported 

here to show resolution in a low dissolved oxygen environment, rather than set all values to <2.0 mg/L; zero values should be interpreted as <0.1 mg/L]

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Station 08470450 February data-collection period

08470450 02/22/2006 10:30 17.8 3,500 7.6 7.5

08470450 02/22/2006 10:45 17.8 3,510 7.7 7.6

08470450 02/22/2006 11:00 18.1 3,440 7.8 7.6

08470450 02/22/2006 11:15 18.1 3,470 7.7 7.6

08470450 02/22/2006 11:30 18.1 3,480 7.8 7.6

08470450 02/22/2006 11:45 18.2 3,460 7.8 7.6

08470450 02/22/2006 12:00 18.2 3,490 7.8 7.6

08470450 02/22/2006 12:15 18.3 3,500 7.9 7.6

08470450 02/22/2006 12:30 18.4 3,490 7.8 7.6

08470450 02/22/2006 12:45 18.4 3,510 7.8 7.6

08470450 02/22/2006 13:00 18.6 3,500 7.9 7.6

08470450 02/22/2006 13:15 18.6 3,510 8.0 7.6

08470450 02/22/2006 13:30 18.7 3,510 8.0 7.6

08470450 02/22/2006 13:45 18.7 3,520 8.0 7.6

08470450 02/22/2006 14:00 18.8 3,510 8.1 7.6

08470450 02/22/2006 14:15 19.0 3,500 8.0 7.7

08470450 02/22/2006 14:30 19.0 3,520 8.0 7.6

08470450 02/22/2006 14:45 19.0 3,530 8.1 7.7

08470450 02/22/2006 15:00 19.5 3,460 8.1 7.7

08470450 02/22/2006 15:15 19.4 3,490 8.0 7.7

08470450 02/22/2006 15:30 19.5 3,500 8.0 7.7

08470450 02/22/2006 15:45 19.4 3,530 8.0 7.7

08470450 02/22/2006 16:00 19.5 3,530 8.1 7.7

08470450 02/22/2006 16:15 19.6 3,520 8.1 7.7

08470450 02/22/2006 16:30 19.6 3,540 8.0 7.7

08470450 02/22/2006 16:45 19.6 3,900 8.0 7.7

08470450 02/22/2006 17:00 19.2 3,620 8.1 7.7

08470450 02/22/2006 17:15 19.3 3,620 8.2 7.7

08470450 02/22/2006 17:30 19.3 3,630 8.1 7.7

08470450 02/22/2006 17:45 19.3 3,630 8.1 7.7

08470450 02/22/2006 18:00 19.2 4,420 7.4 7.6

08470450 02/22/2006 18:15 19.0 7,600 6.2 7.6

08470450 02/22/2006 18:30 18.9 8,500 6.2 7.6

08470450 02/22/2006 18:45 18.8 10,600 6.2 7.6

08470450 02/22/2006 19:00 18.8 9,380 5.5 7.7

08470450 02/22/2006 19:15 19.0 8,610 5.7 7.7

08470450 02/22/2006 19:30 19.0 9,450 6.1 7.6

08470450 02/22/2006 19:45 19.0 10,100 6.2 7.6

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Station 08470450 February data-collection period—Continued

08470450 02/22/2006 20:00 19.0 9,980 6.1 7.7

08470450 02/22/2006 20:15 19.0 11,200 5.9 7.7

08470450 02/22/2006 20:30 19.0 10,400 6.4 7.7

08470450 02/22/2006 20:45 19.1 8,400 6.7 7.7

08470450 02/22/2006 21:00 19.1 8,830 6.8 7.6

08470450 02/22/2006 21:15 19.2 8,070 7.0 7.6

08470450 02/22/2006 21:30 19.2 7,550 7.2 7.6

08470450 02/22/2006 21:45 19.3 6,200 7.2 7.7

08470450 02/22/2006 22:00 19.3 6,050 7.2 7.6

08470450 02/22/2006 22:15 19.4 5,420 7.3 7.7

08470450 02/22/2006 22:30 19.4 4,690 7.5 7.7

08470450 02/22/2006 22:45 19.5 3,880 7.6 7.7

08470450 02/22/2006 23:00 19.5 3,730 7.6 7.7

08470450 02/22/2006 23:15 19.5 3,730 7.5 7.7

08470450 02/22/2006 23:30 19.6 3,730 7.5 7.7

08470450 02/22/2006 23:45 19.6 3,730 7.5 7.7

08470450 02/23/2006 00:00 19.6 3,730 7.4 7.7

08470450 02/23/2006 00:15 19.7 3,740 7.5 7.7

08470450 02/23/2006 00:30 19.7 3,740 7.4 7.7

08470450 02/23/2006 00:45 19.8 3,740 7.3 7.7

08470450 02/23/2006 01:00 19.8 3,750 7.3 7.6

08470450 02/23/2006 01:15 19.8 3,740 7.3 7.7

08470450 02/23/2006 01:30 19.9 3,750 7.3 7.6

08470450 02/23/2006 01:45 19.9 3,750 7.3 7.6

08470450 02/23/2006 02:00 19.9 3,750 7.3 7.6

08470450 02/23/2006 02:15 20.0 3,750 7.2 7.6

08470450 02/23/2006 02:30 20.0 3,750 7.2 7.6

08470450 02/23/2006 02:45 20.1 3,740 7.1 7.6

08470450 02/23/2006 03:00 20.1 3,740 7.1 7.6

08470450 02/23/2006 03:15 20.1 3,740 7.2 7.6

08470450 02/23/2006 03:30 20.2 3,730 7.2 7.6

08470450 02/23/2006 03:45 20.2 3,730 7.1 7.6

08470450 02/23/2006 04:00 20.2 3,730 7.0 7.6

08470450 02/23/2006 04:15 20.2 3,720 7.1 7.6

08470450 02/23/2006 04:30 20.3 3,720 7.1 7.6

08470450 02/23/2006 04:45 20.3 3,720 7.0 7.6

08470450 02/23/2006 05:00 20.3 3,710 7.0 7.6

08470450 02/23/2006 05:15 20.3 3,710 7.0 7.6
14 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–1.2. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470450 February data-collection period—Continued

08470450 02/23/2006 05:30 20.4 3,720 6.9 7.6

08470450 02/23/2006 05:45 20.4 3,720 7.0 7.6

08470450 02/23/2006 06:00 20.4 3,720 7.0 7.6

08470450 02/23/2006 06:15 20.4 3,720 6.9 7.6

08470450 02/23/2006 06:30 20.4 3,720 6.8 7.6

08470450 02/23/2006 06:45 20.4 3,720 6.9 7.6

08470450 02/23/2006 07:00 20.4 3,730 6.9 7.6

08470450 02/23/2006 07:15 20.4 3,730 6.8 7.6

08470450 02/23/2006 07:30 20.4 3,740 6.8 7.6

08470450 02/23/2006 07:45 20.4 3,740 6.8 7.6

08470450 02/23/2006 08:00 20.5 3,740 6.7 7.6

08470450 02/23/2006 08:15 20.5 3,740 6.7 7.6

08470450 02/23/2006 08:30 20.5 3,750 6.7 7.6

08470450 02/23/2006 08:45 20.5 3,760 6.8 7.6

08470450 02/23/2006 09:00 20.5 3,760 6.7 7.6

08470450 02/23/2006 09:15 20.6 3,760 6.8 7.6

08470450 02/23/2006 09:30 20.6 3,770 6.8 7.6

08470450 02/23/2006 09:45 20.6 3,770 6.7 7.6

08470450 02/23/2006 10:00 20.6 3,770 6.8 7.6

08470450 02/23/2006 10:15 20.6 3,780 6.7 7.6

08470450 02/23/2006 10:30 20.6 3,780 6.7 7.6

08470450 02/23/2006 10:45 20.6 3,780 6.7 7.6

08470450 02/23/2006 11:00 20.6 3,780 6.7 7.6

08470450 02/23/2006 11:15 20.5 3,790 6.7 7.6

08470450 02/23/2006 11:30 20.5 3,790 6.8 7.6

08470450 02/23/2006 11:45 20.5 3,790 6.8 7.6

08470450 02/23/2006 12:00 20.4 3,790 6.8 7.6

08470450 02/23/2006 12:15 20.4 3,800 6.8 7.6

08470450 02/23/2006 12:30 20.4 3,800 6.8 7.6

08470450 02/23/2006 12:45 20.4 3,800 6.9 7.6

08470450 02/23/2006 13:00 20.4 3,800 7.0 7.6

Station 08470450 May data-collection period

08470450 05/23/2006 11:45 28.2 4,330 5.3 7.7

08470450 05/23/2006 12:00 28.2 4,330 5.1 7.7

08470450 05/23/2006 12:15 28.3 4,330 5.4 7.7

08470450 05/23/2006 12:30 28.3 4,330 5.4 7.7

08470450 05/23/2006 12:45 28.3 4,340 5.4 7.7

08470450 05/23/2006 13:00 28.4 4,340 5.5 7.7

08470450 05/23/2006 13:15 28.4 4,340 4.3 7.7

08470450 05/23/2006 13:30 28.4 4,340 4.3 7.7

08470450 05/23/2006 13:45 28.5 4,340 4.4 7.7

08470450 05/23/2006 14:00 28.5 4,350 4.5 7.7

08470450 05/23/2006 14:15 28.6 4,350 4.7 7.7

08470450 05/23/2006 14:30 28.6 4,350 5.9 7.7

08470450 05/23/2006 14:45 28.6 4,350 5.9 7.7

08470450 05/23/2006 15:00 28.7 4,350 6.0 7.7

08470450 05/23/2006 15:15 28.8 4,360 6.1 7.7

08470450 05/23/2006 15:30 28.9 4,350 6.2 7.8

08470450 05/23/2006 15:45 29.0 4,350 6.2 7.8

08470450 05/23/2006 16:00 29.1 4,340 6.4 7.8

08470450 05/23/2006 16:15 29.1 4,340 6.3 7.8

08470450 05/23/2006 16:30 29.2 4,340 6.4 7.8

08470450 05/23/2006 16:45 29.2 4,340 6.4 7.8

08470450 05/23/2006 17:00 29.2 4,340 6.4 7.8

08470450 05/23/2006 17:15 29.2 4,340 6.4 7.8

08470450 05/23/2006 17:30 29.3 4,350 6.5 7.8

08470450 05/23/2006 17:45 29.4 4,350 6.6 7.8

08470450 05/23/2006 18:00 29.4 4,350 6.6 7.8

08470450 05/23/2006 18:15 29.5 4,350 6.7 7.8

08470450 05/23/2006 18:30 29.5 4,350 6.7 7.8

08470450 05/23/2006 18:45 29.6 4,350 6.8 7.8

08470450 05/23/2006 19:00 29.6 4,350 6.9 7.8

08470450 05/23/2006 19:15 29.6 4,350 6.9 7.8

08470450 05/23/2006 19:30 29.6 4,360 7.0 7.8

08470450 05/23/2006 19:45 29.5 4,350 7.0 7.8

08470450 05/23/2006 20:00 29.5 4,350 7.0 7.8

08470450 05/23/2006 20:15 29.4 4,350 6.9 7.8

08470450 05/23/2006 20:30 29.4 4,340 6.9 7.8

08470450 05/23/2006 20:45 29.3 4,350 6.8 7.8

08470450 05/23/2006 21:00 29.2 4,340 6.8 7.8

08470450 05/23/2006 21:15 29.2 4,340 6.8 7.8

08470450 05/23/2006 21:30 29.1 4,330 6.6 7.8

08470450 05/23/2006 21:45 29.1 4,320 6.6 7.8

08470450 05/23/2006 22:00 29.0 4,310 6.5 7.8

08470450 05/23/2006 22:15 29.0 4,300 6.6 7.8

08470450 05/23/2006 22:30 29.0 4,290 6.5 7.8

08470450 05/23/2006 22:45 29.0 4,290 6.6 7.8

08470450 05/23/2006 23:00 29.0 4,280 6.2 7.8

08470450 05/23/2006 23:15 28.9 4,280 6.0 7.8

08470450 05/23/2006 23:30 28.9 4,280 5.2 7.8

08470450 05/23/2006 23:45 28.8 4,270 4.8 7.8

08470450 05/24/2006 00:00 28.8 4,270 4.8 7.7

08470450 05/24/2006 00:15 28.8 4,270 4.7 7.8

08470450 05/24/2006 00:30 28.7 4,270 4.5 7.8

08470450 05/24/2006 00:45 28.7 4,270 4.6 7.7

08470450 05/24/2006 01:00 28.6 4,260 4.5 7.7

08470450 05/24/2006 01:15 28.6 4,260 4.4 7.7

08470450 05/24/2006 01:30 28.6 4,260 4.4 7.7

08470450 05/24/2006 01:45 28.5 4,260 6.1 7.7

08470450 05/24/2006 02:00 28.5 4,260 6.1 7.7

08470450 05/24/2006 02:15 28.5 4,260 6.0 7.7

08470450 05/24/2006 02:30 28.5 4,260 5.9 7.7

08470450 05/24/2006 02:45 28.5 4,260 5.8 7.7

08470450 05/24/2006 03:00 28.5 4,260 5.8 7.7

08470450 05/24/2006 03:15 28.5 4,260 5.7 7.7

08470450 05/24/2006 03:30 28.5 4,270 5.6 7.7

08470450 05/24/2006 03:45 28.5 4,270 5.5 7.7

08470450 05/24/2006 04:00 28.5 4,280 5.5 7.7

08470450 05/24/2006 04:15 28.5 4,290 5.5 7.7

08470450 05/24/2006 04:30 28.4 4,300 5.3 7.7

08470450 05/24/2006 04:45 28.4 4,300 5.3 7.7

08470450 05/24/2006 05:00 28.4 4,320 5.2 7.7

08470450 05/24/2006 05:15 28.4 4,320 5.1 7.7

08470450 05/24/2006 05:30 28.4 4,330 5.0 7.7

08470450 05/24/2006 05:45 28.4 4,340 4.9 7.7

08470450 05/24/2006 06:00 28.4 4,350 4.9 7.7

08470450 05/24/2006 06:15 28.4 4,360 4.9 7.7

08470450 05/24/2006 06:30 28.4 4,360 4.9 7.7

08470450 05/24/2006 06:45 28.4 4,370 4.9 7.7

08470450 05/24/2006 07:00 28.4 4,380 4.9 7.7

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Station 08470450 May data-collection period—Continued

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)
Appendix 1 15

Appendix 1–1.2. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470450 May data-collection period—Continued

08470450 05/24/2006 07:15 28.4 4,380 4.9 7.7

08470450 05/24/2006 07:30 28.3 4,380 4.9 7.7

08470450 05/24/2006 07:45 28.3 4,380 4.8 7.7

08470450 05/24/2006 08:00 28.3 4,390 4.8 7.7

08470450 05/24/2006 08:15 28.2 4,390 4.8 7.7

08470450 05/24/2006 08:30 28.2 4,400 4.7 7.7

08470450 05/24/2006 08:45 28.2 4,400 4.7 7.7

08470450 05/24/2006 09:00 28.2 4,410 4.7 7.7

08470450 05/24/2006 09:15 28.1 4,420 4.7 7.7

08470450 05/24/2006 09:30 28.1 4,420 4.6 7.7

08470450 05/24/2006 09:45 28.1 4,420 4.6 7.7

08470450 05/24/2006 10:00 28.1 4,420 4.7 7.7

08470450 05/24/2006 10:15 28.1 4,420 4.7 7.7

08470450 05/24/2006 10:30 28.1 4,410 4.8 7.7

08470450 05/24/2006 10:45 28.1 4,410 4.8 7.7

08470450 05/24/2006 11:00 28.1 4,410 4.8 7.7

08470450 05/24/2006 11:15 28.1 4,400 4.9 7.7

08470450 05/24/2006 11:30 28.2 4,390 5.0 7.7

08470450 05/24/2006 11:45 28.2 4,390 5.0 7.7

08470450 05/24/2006 12:00 28.3 4,380 5.0 7.7

08470450 05/24/2006 12:15 28.4 4,380 5.1 7.7

08470450 05/24/2006 12:30 28.4 4,380 5.2 7.7

08470450 05/24/2006 12:45 28.5 4,370 5.3 7.7

Station 08470460 February data-collection period

08470460 02/22/2006 09:45 16.1 51,100 1.0 7.9

08470460 02/22/2006 10:00 16.0 51,000 .9 7.9

08470460 02/22/2006 10:15 16.0 51,100 1.1 7.9

08470460 02/22/2006 10:30 16.0 51,000 1.1 8.0

08470460 02/22/2006 10:45 16.0 51,100 .9 8.0

08470460 02/22/2006 11:00 16.1 51,100 .5 7.9

08470460 02/22/2006 11:15 16.1 51,100 .5 8.0

08470460 02/22/2006 11:30 16.1 51,100 .3 8.0

08470460 02/22/2006 11:45 16.1 51,100 .3 8.0

08470460 02/22/2006 12:00 16.1 51,200 .3 8.0

08470460 02/22/2006 12:15 16.1 51,200 .2 8.0

08470460 02/22/2006 12:30 16.1 51,200 .3 8.0

08470460 02/22/2006 12:45 16.1 51,300 .2 8.0

08470460 02/22/2006 13:00 16.1 51,200 .2 8.0

08470460 02/22/2006 13:15 16.1 51,300 .2 8.0

08470460 02/22/2006 13:30 16.1 51,400 .2 8.0

08470460 02/22/2006 13:45 16.1 51,300 .2 8.0

08470460 02/22/2006 14:00 16.1 51,400 .2 8.0

08470460 02/22/2006 14:15 16.1 51,500 .3 8.0

08470460 02/22/2006 14:30 16.1 51,500 .4 8.0

08470460 02/22/2006 14:45 16.1 51,400 .2 8.0

08470460 02/22/2006 15:00 16.1 51,500 .4 8.0

08470460 02/22/2006 15:15 16.1 51,500 .5 8.0

08470460 02/22/2006 15:30 16.1 51,400 .3 8.0

08470460 02/22/2006 15:45 16.0 51,500 .7 8.0

08470460 02/22/2006 16:00 16.0 51,500 .8 8.0

08470460 02/22/2006 16:15 16.0 51,500 .9 8.0

08470460 02/22/2006 16:30 16.0 51,600 .6 8.0

08470460 02/22/2006 16:45 16.1 51,600 .6 8.0

08470460 02/22/2006 17:00 16.0 51,600 .8 8.0

08470460 02/22/2006 17:15 16.0 51,600 .7 8.0

08470460 02/22/2006 17:30 16.0 51,600 0.9 8.0

08470460 02/22/2006 17:45 16.0 51,600 1.0 8.0

08470460 02/22/2006 18:00 16.1 51,600 .7 8.0

08470460 02/22/2006 18:15 16.1 51,700 .7 8.0

08470460 02/22/2006 18:30 16.1 51,700 .7 8.0

08470460 02/22/2006 18:45 16.0 51,700 .9 8.0

08470460 02/22/2006 19:00 16.0 51,700 .9 8.0

08470460 02/22/2006 19:15 16.0 51,700 .8 8.0

08470460 02/22/2006 19:30 16.1 51,800 .7 8.0

08470460 02/22/2006 19:45 16.0 51,700 .9 8.0

08470460 02/22/2006 20:00 16.1 51,800 .8 8.0

08470460 02/22/2006 20:15 16.0 51,800 .8 8.0

08470460 02/22/2006 20:30 16.1 51,800 .8 8.0

08470460 02/22/2006 20:45 16.1 51,800 .7 8.0

08470460 02/22/2006 21:00 16.1 51,800 .7 8.0

08470460 02/22/2006 21:15 16.1 51,800 .9 8.0

08470460 02/22/2006 21:30 16.0 51,800 .8 8.0

08470460 02/22/2006 21:45 16.0 51,800 .9 8.0

08470460 02/22/2006 22:00 16.0 51,700 .9 8.0

08470460 02/22/2006 22:15 16.1 51,800 .9 8.0

08470460 02/22/2006 22:30 16.0 51,700 .9 8.0

08470460 02/22/2006 22:45 16.1 51,700 .9 8.0

08470460 02/22/2006 23:00 16.1 51,800 .8 8.0

08470460 02/22/2006 23:15 16.1 51,600 .8 8.0

08470460 02/22/2006 23:30 16.1 51,700 .8 8.0

08470460 02/22/2006 23:45 16.1 51,800 .8 8.0

08470460 02/23/2006 00:00 16.1 51,800 .8 8.0

08470460 02/23/2006 00:15 16.1 51,800 .8 8.0

08470460 02/23/2006 00:30 16.1 51,800 .8 8.0

08470460 02/23/2006 00:45 16.0 51,800 .9 8.0

08470460 02/23/2006 01:00 16.0 51,800 .8 8.0

08470460 02/23/2006 01:15 16.1 51,700 .8 8.0

08470460 02/23/2006 01:30 16.1 51,700 .8 8.0

08470460 02/23/2006 01:45 16.1 51,800 .8 8.0

08470460 02/23/2006 02:00 16.0 51,800 .8 8.0

08470460 02/23/2006 02:15 16.1 51,800 .8 8.0

08470460 02/23/2006 02:30 16.1 51,800 .7 8.0

08470460 02/23/2006 02:45 16.1 51,700 .7 8.0

08470460 02/23/2006 03:00 16.1 51,700 .7 8.0

08470460 02/23/2006 03:15 16.1 51,700 .7 8.0

08470460 02/23/2006 03:30 16.1 51,700 .7 8.0

08470460 02/23/2006 03:45 16.1 51,700 .7 8.0

08470460 02/23/2006 04:00 16.1 51,700 .7 8.0

08470460 02/23/2006 04:15 16.1 51,600 .8 8.0

08470460 02/23/2006 04:30 16.1 51,600 .6 8.0

08470460 02/23/2006 04:45 16.1 51,600 .7 8.0

08470460 02/23/2006 05:00 16.1 51,600 .6 8.0

08470460 02/23/2006 05:15 16.1 51,600 .6 8.0

08470460 02/23/2006 05:30 16.1 51,600 .6 8.0

08470460 02/23/2006 05:45 16.1 51,600 .6 8.0

08470460 02/23/2006 06:00 16.2 51,600 .5 8.0

08470460 02/23/2006 06:15 16.2 51,600 .5 8.0

08470460 02/23/2006 06:30 16.1 51,600 .6 8.0

08470460 02/23/2006 06:45 16.1 51,600 .6 8.0

08470460 02/23/2006 07:00 16.1 51,500 .7 8.0

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Station 08470460 February data-collection period—Continued

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)
16 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–1.2. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470460 February data-collection period—Continued

08470460 02/23/2006 07:15 16.1 51,500 0.6 8.0

08470460 02/23/2006 07:30 16.1 51,600 .7 8.0

08470460 02/23/2006 07:45 16.1 51,500 .6 8.0

08470460 02/23/2006 08:00 16.1 51,500 .6 8.0

08470460 02/23/2006 08:15 16.1 51,600 .6 8.0

08470460 02/23/2006 08:30 16.1 51,600 .6 8.0

08470460 02/23/2006 08:45 16.1 51,600 .6 8.0

08470460 02/23/2006 09:00 16.1 51,600 .6 8.0

08470460 02/23/2006 09:15 16.1 51,600 .5 8.0

08470460 02/23/2006 09:30 16.1 51,600 .5 8.0

08470460 02/23/2006 09:45 16.1 51,700 .5 8.0

08470460 02/23/2006 10:00 16.1 51,700 .5 8.0

08470460 02/23/2006 10:15 16.1 51,600 .5 8.0

08470460 02/23/2006 10:30 16.2 51,600 .5 8.0

08470460 02/23/2006 10:45 16.2 51,500 .5 8.0

08470460 02/23/2006 11:00 16.2 51,400 .5 8.0

08470460 02/23/2006 11:15 16.2 51,300 .4 8.0

08470460 02/23/2006 11:30 16.2 51,100 .4 8.0

08470460 02/23/2006 11:45 16.2 51,100 .5 8.0

08470460 02/23/2006 12:00 16.2 50,700 .4 8.0

08470460 02/23/2006 12:15 16.3 50,600 .4 8.0

08470460 02/23/2006 12:30 16.2 51,100 .4 8.0

08470460 02/23/2006 12:45 16.3 50,600 .5 8.0

08470460 02/23/2006 13:00 16.3 50,900 .4 8.0

08470460 02/23/2006 13:15 16.3 50,600 .4 8.0

08470460 02/23/2006 13:30 16.3 50,500 .6 8.0

08470460 02/23/2006 13:45 16.3 48,700 .6 7.9

Station 08470460 May data-collection period

08470460 05/23/2006 11:15 26.6 24,300 .2 6.9

08470460 05/23/2006 11:30 26.6 23,900 .1 6.9

08470460 05/23/2006 11:45 26.6 23,900 .1 6.9

08470460 05/23/2006 12:00 26.6 23,900 .1 6.9

08470460 05/23/2006 12:15 26.6 23,800 .1 6.9

08470460 05/23/2006 12:30 26.6 23,800 .1 6.9

08470460 05/23/2006 12:45 26.6 23,800 .1 6.9

08470460 05/23/2006 13:00 26.6 23,800 .1 6.9

08470460 05/23/2006 13:15 26.6 23,800 .1 6.9

08470460 05/23/2006 13:30 26.6 23,800 .1 6.9

08470460 05/23/2006 13:45 26.6 23,800 .1 6.9

08470460 05/23/2006 14:00 26.6 23,800 .1 6.9

08470460 05/23/2006 14:15 26.6 23,900 .1 6.9

08470460 05/23/2006 14:30 26.6 23,800 .1 6.9

08470460 05/23/2006 14:45 26.6 23,800 .1 6.9

08470460 05/23/2006 15:00 26.6 23,800 .1 6.9

08470460 05/23/2006 15:15 26.6 23,700 .1 6.9

08470460 05/23/2006 15:30 26.6 23,700 .1 6.9

08470460 05/23/2006 15:45 26.6 23,700 .1 6.9

08470460 05/23/2006 16:00 27.0 23,500 .1 6.9

08470460 05/23/2006 16:15 27.0 23,700 .1 6.9

08470460 05/23/2006 16:30 27.1 23,600 .1 6.9

08470460 05/23/2006 16:45 27.1 23,500 .1 6.9

08470460 05/23/2006 17:00 27.4 23,500 .1 6.9

08470460 05/23/2006 17:15 26.8 23,500 .1 6.9

08470460 05/23/2006 17:30 26.8 23,400 .1 6.9

08470460 05/23/2006 17:45 27.0 23,400 .1 6.9

08470460 05/23/2006 18:00 27.0 23,300 0.1 6.9

08470460 05/23/2006 18:15 26.9 23,300 .1 6.9

08470460 05/23/2006 18:30 26.9 23,200 .1 6.9

08470460 05/23/2006 18:45 26.9 23,200 .1 6.9

08470460 05/23/2006 19:00 26.9 23,200 .1 6.9

08470460 05/23/2006 19:15 26.9 23,200 .1 6.9

08470460 05/23/2006 19:30 26.9 23,100 .1 6.9

08470460 05/23/2006 19:45 26.9 23,100 .1 6.9

08470460 05/23/2006 20:00 26.9 23,100 .1 6.9

08470460 05/23/2006 20:15 26.9 23,100 .1 6.9

08470460 05/23/2006 20:30 26.9 23,100 .1 6.9

08470460 05/23/2006 20:45 26.9 23,100 .1 6.9

08470460 05/23/2006 21:00 26.9 23,100 .1 6.9

08470460 05/23/2006 21:15 26.8 23,100 .1 6.9

08470460 05/23/2006 21:30 26.8 23,100 .1 6.9

08470460 05/23/2006 21:45 26.8 23,100 .1 6.9

08470460 05/23/2006 22:00 26.8 23,100 .1 6.9

08470460 05/23/2006 22:15 26.8 23,100 .1 6.9

08470460 05/23/2006 22:30 26.8 23,100 .1 6.9

08470460 05/23/2006 22:45 26.8 23,100 .1 6.9

08470460 05/23/2006 23:00 26.8 23,100 .1 6.9

08470460 05/23/2006 23:15 26.8 23,100 .1 6.9

08470460 05/23/2006 23:30 26.8 23,100 .1 6.9

08470460 05/23/2006 23:45 26.8 23,100 .1 6.9

08470460 05/24/2006 00:00 26.8 23,100 .1 6.9

08470460 05/24/2006 00:15 26.8 23,100 .1 6.9

08470460 05/24/2006 00:30 26.8 23,100 .1 6.9

08470460 05/24/2006 00:45 26.8 23,100 .1 6.9

08470460 05/24/2006 01:00 26.8 23,100 0 6.9

08470460 05/24/2006 01:15 26.8 23,100 .1 6.9

08470460 05/24/2006 01:30 26.8 23,100 .1 6.9

08470460 05/24/2006 01:45 26.8 23,100 .1 6.9

08470460 05/24/2006 02:00 26.8 23,100 .1 6.9

08470460 05/24/2006 02:15 26.8 23,100 .1 6.9

08470460 05/24/2006 02:30 26.8 23,100 .1 6.9

08470460 05/24/2006 02:45 26.8 23,100 .1 6.9

08470460 05/24/2006 03:00 26.8 23,100 .1 6.9

08470460 05/24/2006 03:15 26.8 23,100 0 6.9

08470460 05/24/2006 03:30 26.8 23,100 .1 6.9

08470460 05/24/2006 03:45 26.8 23,100 0 6.9

08470460 05/24/2006 04:00 26.8 23,100 0 6.9

08470460 05/24/2006 04:15 26.8 23,100 0 6.9

08470460 05/24/2006 04:30 26.8 23,200 0 6.9

08470460 05/24/2006 04:45 26.8 23,100 .1 6.9

08470460 05/24/2006 05:00 26.8 23,100 .1 6.9

08470460 05/24/2006 05:15 26.8 23,100 0 6.9

08470460 05/24/2006 05:30 26.8 23,100 .1 6.9

08470460 05/24/2006 05:45 26.8 23,100 0 6.9

08470460 05/24/2006 06:00 26.8 23,100 .1 6.9

08470460 05/24/2006 06:15 26.8 23,100 0 6.9

08470460 05/24/2006 06:30 26.8 23,100 .1 6.9

08470460 05/24/2006 06:45 26.8 23,100 .1 6.9

08470460 05/24/2006 07:00 26.8 23,100 .1 6.9

08470460 05/24/2006 07:15 26.7 23,200 .1 6.9

08470460 05/24/2006 07:30 26.7 23,100 0 6.9

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Station 08470460 May data-collection period—Continued

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)
Appendix 1 17

Appendix 1–1.2. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470460 May data-collection period—Continued

08470460 05/24/2006 07:45 26.7 23,100 0.1 6.9

08470460 05/24/2006 08:00 26.7 23,100 0 6.9

08470460 05/24/2006 08:15 26.8 23,100 .1 6.9

08470460 05/24/2006 08:30 26.8 23,100 .1 6.9

08470460 05/24/2006 08:45 26.8 23,100 0 6.9

08470460 05/24/2006 09:00 26.8 23,100 .1 6.9

08470460 05/24/2006 09:15 26.8 23,100 0 6.9

08470460 05/24/2006 09:30 26.8 23,100 .1 6.9

08470460 05/24/2006 09:45 26.8 23,100 0 6.9

08470460 05/24/2006 10:00 26.8 23,100 0 6.9

08470460 05/24/2006 10:15 26.8 23,100 0 6.9

08470460 05/24/2006 10:30 26.8 23,100 .1 6.9

08470460 05/24/2006 10:45 26.8 23,100 0 6.9

08470460 05/24/2006 11:00 26.8 23,100 .1 6.9

08470460 05/24/2006 11:15 26.8 23,100 .1 6.9

08470460 05/24/2006 11:30 26.8 23,100 .1 6.9

08470460 05/24/2006 11:45 26.8 23,100 0 6.9

08470460 05/24/2006 12:00 26.8 23,100 0 6.9

08470460 05/24/2006 12:15 26.8 23,100 0 6.9

08470460 05/24/2006 12:30 26.8 23,100 0 6.9

08470460 05/24/2006 12:45 26.8 23,100 .1 6.9

08470460 05/24/2006 13:00 26.8 23,100 0 6.9

Station 08470500 February data-collection period

08470500 02/22/2006 11:10 16.2 53,000 1.4 8.0

08470500 02/22/2006 11:25 16.2 52,100 1.4 8.0

08470500 02/22/2006 11:40 16.3 51,300 1.4 8.0

08470500 02/22/2006 11:55 16.3 52,400 1.3 8.0

08470500 02/22/2006 12:10 16.3 52,800 1.3 8.0

08470500 02/22/2006 12:25 16.3 52,400 1.3 8.0

08470500 02/22/2006 12:40 16.4 53,000 1.2 8.0

08470500 02/22/2006 12:55 16.4 53,000 1.1 8.0

08470500 02/22/2006 13:10 16.4 52,300 1.2 8.0

08470500 02/22/2006 13:25 16.4 52,900 1.1 8.0

08470500 02/22/2006 13:40 16.4 52,800 1.2 8.0

08470500 02/22/2006 13:55 16.4 52,600 1.3 8.0

08470500 02/22/2006 14:10 16.5 53,200 1.1 8.1

08470500 02/22/2006 14:25 16.5 53,500 1.0 8.1

08470500 02/22/2006 14:40 16.6 53,800 .9 8.1

08470500 02/22/2006 14:55 16.6 53,600 1.0 8.1

08470500 02/22/2006 15:10 16.5 53,200 1.0 8.1

08470500 02/22/2006 15:25 16.6 53,500 1.1 8.1

08470500 02/22/2006 15:40 16.6 53,600 .9 8.1

08470500 02/22/2006 15:55 16.6 53,800 1.0 8.1

08470500 02/22/2006 16:10 16.6 53,900 .9 8.1

08470500 02/22/2006 16:25 16.6 53,800 1.0 8.1

08470500 02/22/2006 16:40 16.7 53,800 .9 8.1

08470500 02/22/2006 16:55 16.7 54,000 .9 8.1

08470500 02/22/2006 17:10 16.7 54,100 .9 8.1

08470500 02/22/2006 17:25 16.7 54,000 .9 8.1

08470500 02/22/2006 17:40 16.7 53,900 .9 8.1

08470500 02/22/2006 17:55 16.7 53,900 .9 8.1

08470500 02/22/2006 18:10 16.7 54,100 .9 8.1

08470500 02/22/2006 18:25 16.7 54,000 .8 8.1

08470500 02/22/2006 18:40 16.7 54,000 .9 8.1

08470500 02/22/2006 18:55 16.7 54,000 .8 8.1

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Station 08470500 February data-collection period—Continued

08470500 02/22/2006 19:10 16.7 54,100 0.9 8.1

08470500 02/22/2006 19:25 16.7 54,000 .9 8.1

08470500 02/22/2006 19:40 16.7 54,100 .8 8.1

08470500 02/22/2006 19:55 16.7 54,100 .8 8.1

08470500 02/22/2006 20:10 16.7 54,100 .8 8.1

08470500 02/22/2006 20:25 16.7 54,100 .9 8.1

08470500 02/22/2006 20:40 16.7 53,900 .9 8.1

08470500 02/22/2006 20:55 16.7 53,900 .8 8.1

08470500 02/22/2006 21:10 16.7 53,800 .9 8.1

08470500 02/22/2006 21:25 16.7 53,800 .9 8.1

08470500 02/22/2006 21:40 16.7 54,000 .9 8.1

08470500 02/22/2006 21:55 16.6 53,800 .9 8.1

08470500 02/22/2006 22:10 16.7 53,900 .9 8.1

08470500 02/22/2006 22:25 16.7 53,900 .8 8.1

08470500 02/22/2006 22:40 16.7 53,800 .9 8.1

08470500 02/22/2006 22:55 16.7 53,800 .8 8.1

08470500 02/22/2006 23:10 16.7 53,700 .9 8.1

08470500 02/22/2006 23:25 16.6 53,600 .9 8.1

08470500 02/22/2006 23:40 16.6 53,800 .8 8.1

08470500 02/22/2006 23:55 16.6 53,700 .9 8.1

08470500 02/23/2006 00:10 16.6 53,600 .9 8.1

08470500 02/23/2006 00:25 16.6 53,500 .9 8.1

08470500 02/23/2006 00:40 16.6 53,300 .9 8.1

08470500 02/23/2006 00:55 16.5 53,200 .9 8.1

08470500 02/23/2006 01:10 16.5 52,900 .9 8.1

08470500 02/23/2006 01:25 16.5 52,400 1.1 8.0

08470500 02/23/2006 01:40 16.5 52,500 1.1 8.1

08470500 02/23/2006 01:55 16.4 52,500 1.1 8.1

08470500 02/23/2006 02:10 16.4 52,500 1.0 8.1

08470500 02/23/2006 02:25 16.4 52,400 1.2 8.1

08470500 02/23/2006 02:40 16.4 52,600 1.1 8.1

08470500 02/23/2006 02:55 16.4 52,500 1.1 8.1

08470500 02/23/2006 03:10 16.4 52,900 1.1 8.1

08470500 02/23/2006 03:25 16.4 52,100 1.1 8.1

08470500 02/23/2006 03:40 16.4 52,600 1.1 8.1

08470500 02/23/2006 03:55 16.4 52,600 1.1 8.1

08470500 02/23/2006 04:10 16.4 53,000 1.0 8.1

08470500 02/23/2006 04:25 16.4 52,900 .9 8.1

08470500 02/23/2006 04:40 16.4 53,100 1.0 8.1

08470500 02/23/2006 04:55 16.4 52,800 1.0 8.1

08470500 02/23/2006 05:10 16.4 52,900 1.0 8.1

08470500 02/23/2006 05:25 16.4 53,300 .9 8.1

08470500 02/23/2006 05:40 16.4 53,000 1.1 8.1

08470500 02/23/2006 05:55 16.4 52,900 1.0 8.1

08470500 02/23/2006 06:10 16.4 53,000 1.0 8.1

08470500 02/23/2006 06:25 16.4 53,000 1.1 8.1

08470500 02/23/2006 06:40 16.2 52,800 1.2 8.1

08470500 02/23/2006 06:55 16.2 52,900 1.1 8.1

08470500 02/23/2006 07:10 16.2 52,600 1.2 8.1

08470500 02/23/2006 07:25 16.2 52,000 1.3 8.1

08470500 02/23/2006 07:40 16.4 53,000 1.0 8.1

08470500 02/23/2006 07:55 16.3 53,000 1.0 8.1

08470500 02/23/2006 08:10 16.3 52,900 1.0 8.1

08470500 02/23/2006 08:25 16.2 53,000 1.1 8.1

08470500 02/23/2006 08:40 16.2 52,500 1.1 8.1

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)
18 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–1.2. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470500 February data-collection period—Continued

08470500 02/23/2006 08:55 16.1 52,300 1.2 8.1

08470500 02/23/2006 09:10 16.2 52,500 1.1 8.1

08470500 02/23/2006 09:25 16.1 51,700 1.3 8.0

08470500 02/23/2006 09:40 16.1 51,800 1.2 8.0

08470500 02/23/2006 09:55 16.0 51,600 1.4 8.0

08470500 02/23/2006 10:10 15.9 51,600 1.6 8.0

08470500 02/23/2006 10:25 16.0 51,500 1.5 8.0

08470500 02/23/2006 10:40 16.0 51,100 1.6 8.0

08470500 02/23/2006 10:55 16.1 51,700 1.4 8.0

08470500 02/23/2006 11:10 15.9 51,000 1.6 8.0

08470500 02/23/2006 11:25 16.0 50,900 1.3 8.0

08470500 02/23/2006 11:40 16.0 51,600 1.3 8.0

08470500 02/23/2006 11:55 16.1 51,300 1.3 8.0

08470500 02/23/2006 12:10 16.1 51,200 1.3 8.0

08470500 02/23/2006 12:25 16.1 51,900 1.1 8.0

08470500 02/23/2006 12:40 16.1 50,800 1.1 8.0

08470500 02/23/2006 12:55 16.2 50,800 1.1 8.0

08470500 02/23/2006 13:10 16.3 50,300 1.0 8.0

08470500 02/23/2006 13:25 16.3 50,400 1.0 8.0

08470500 02/23/2006 13:40 16.4 49,700 1.0 8.0

08470500 02/23/2006 13:55 16.6 49,200 .9 8.0

08470500 02/23/2006 14:10 16.5 49,600 .9 8.0

08470500 02/23/2006 14:25 16.4 50,000 .9 8.0

Station 08470500 May data-collection period

08470500 05/23/2006 10:45 26.7 34,200 .2 7.6

08470500 05/23/2006 11:00 26.7 33,900 .2 7.6

08470500 05/23/2006 11:15 26.7 34,100 .2 7.6

08470500 05/23/2006 11:30 26.7 34,100 .2 7.6

08470500 05/23/2006 11:45 26.7 33,900 .1 7.6

08470500 05/23/2006 12:00 26.7 33,900 .2 7.6

08470500 05/23/2006 12:15 26.7 33,600 .1 7.6

08470500 05/23/2006 12:30 26.7 33,100 .2 7.6

08470500 05/23/2006 12:45 26.7 34,300 .1 7.6

08470500 05/23/2006 13:00 26.7 33,400 .1 7.6

08470500 05/23/2006 13:15 26.7 33,700 .1 7.6

08470500 05/23/2006 13:30 26.7 33,600 .1 7.6

08470500 05/23/2006 13:45 26.7 33,300 .1 7.6

08470500 05/23/2006 14:00 26.7 33,000 .1 7.6

08470500 05/23/2006 14:15 26.7 32,700 .1 7.6

08470500 05/23/2006 14:30 26.7 33,100 .2 7.6

08470500 05/23/2006 14:45 26.7 33,300 .2 7.6

08470500 05/23/2006 15:00 26.7 33,300 .1 7.6

08470500 05/23/2006 15:15 26.7 33,400 .1 7.3

08470500 05/23/2006 15:30 26.7 33,100 .1 7.6

08470500 05/23/2006 15:45 26.7 33,100 .1 7.6

08470500 05/23/2006 16:00 26.7 33,000 .1 7.6

08470500 05/23/2006 16:15 26.7 33,800 .1 7.6

08470500 05/23/2006 16:30 26.7 33,900 .1 7.6

08470500 05/23/2006 16:45 26.7 33,200 .1 7.6

08470500 05/23/2006 17:00 26.7 33,500 .1 7.6

08470500 05/23/2006 17:15 26.7 34,000 .1 7.6

08470500 05/23/2006 17:30 26.7 34,000 .1 7.6

08470500 05/23/2006 17:45 26.7 33,800 .1 7.6

08470500 05/23/2006 18:00 26.7 33,800 .1 7.6

08470500 05/23/2006 18:15 26.7 33,600 .1 7.6

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Station 08470500 May data-collection period—Continued

08470500 05/23/2006 18:30 26.7 34,300 0.1 7.6

08470500 05/23/2006 18:45 26.7 33,700 .1 7.6

08470500 05/23/2006 19:00 26.7 33,600 .1 7.6

08470500 05/23/2006 19:15 26.7 33,700 .1 7.6

08470500 05/23/2006 19:30 26.6 34,400 .1 7.6

08470500 05/23/2006 19:45 26.7 34,000 .1 7.6

08470500 05/23/2006 20:00 26.7 33,700 .1 7.6

08470500 05/23/2006 20:15 26.7 33,800 .1 7.6

08470500 05/23/2006 20:30 26.7 33,300 .1 7.6

08470500 05/23/2006 20:45 26.7 33,200 .1 7.6

08470500 05/23/2006 21:00 26.8 30,400 .1 7.6

08470500 05/23/2006 21:15 26.7 31,100 .1 7.6

08470500 05/23/2006 21:30 26.8 29,300 .1 7.6

08470500 05/23/2006 21:45 26.8 30,800 .1 7.6

08470500 05/23/2006 22:00 26.8 31,400 .1 7.6

08470500 05/23/2006 22:15 26.8 30,300 .1 7.6

08470500 05/23/2006 22:30 26.8 30,300 .1 7.6

08470500 05/23/2006 22:45 26.8 30,100 .1 7.6

08470500 05/23/2006 23:00 27.0 27,700 .1 7.6

08470500 05/23/2006 23:15 27.1 26,100 .1 7.6

08470500 05/23/2006 23:30 27.0 26,900 .1 7.6

08470500 05/23/2006 23:45 27.2 24,700 .1 7.5

08470500 05/24/2006 00:00 27.2 24,700 .1 7.5

08470500 05/24/2006 00:15 27.2 24,700 .1 7.5

08470500 05/24/2006 00:30 27.1 26,000 .1 7.5

08470500 05/24/2006 00:45 27.2 24,800 .1 7.5

08470500 05/24/2006 01:00 27.1 26,200 .1 7.5

08470500 05/24/2006 01:15 27.1 26,900 .1 7.6

08470500 05/24/2006 01:30 26.9 29,700 .1 7.6

08470500 05/24/2006 01:45 26.9 29,800 .1 7.6

08470500 05/24/2006 02:00 26.8 31,100 .1 7.6

08470500 05/24/2006 02:15 26.8 31,900 .1 7.6

08470500 05/24/2006 02:30 26.7 32,700 .1 7.6

08470500 05/24/2006 02:45 26.7 32,300 .1 7.6

08470500 05/24/2006 03:00 26.8 32,200 .1 7.6

08470500 05/24/2006 03:15 26.7 32,400 .1 7.6

08470500 05/24/2006 03:30 26.7 32,700 .1 7.6

08470500 05/24/2006 03:45 26.7 32,500 .1 7.6

08470500 05/24/2006 04:00 26.7 34,200 .1 7.6

08470500 05/24/2006 04:15 26.7 32,400 .1 7.6

08470500 05/24/2006 04:30 26.7 33,600 .1 7.6

08470500 05/24/2006 04:45 26.7 33,200 .1 7.6

08470500 05/24/2006 05:00 26.6 34,300 .1 7.6

08470500 05/24/2006 05:15 26.7 32,900 .1 7.6

08470500 05/24/2006 05:30 26.8 30,400 .1 7.6

08470500 05/24/2006 05:45 26.9 30,200 .1 7.6

08470500 05/24/2006 06:00 27.0 29,200 .1 7.6

08470500 05/24/2006 06:15 26.9 29,800 .1 7.6

08470500 05/24/2006 06:30 26.8 31,800 .1 7.6

08470500 05/24/2006 06:45 26.8 31,900 .1 7.6

08470500 05/24/2006 07:00 26.8 31,500 .1 7.6

08470500 05/24/2006 07:15 26.8 31,900 .1 7.6

08470500 05/24/2006 07:30 26.8 31,300 .1 7.6

08470500 05/24/2006 07:45 26.8 31,300 .1 7.6

08470500 05/24/2006 08:00 26.7 31,800 .1 7.5

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)
Appendix 1 19

Appendix 1–1.2. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470500 May data-collection period—Continued

08470500 05/24/2006 08:15 26.7 32,100 0.1 7.6

08470500 05/24/2006 08:30 26.8 31,400 .1 7.6

08470500 05/24/2006 08:45 27.2 25,000 .7 7.6

08470500 05/24/2006 09:00 27.0 27,900 .3 7.6

08470500 05/24/2006 09:15 26.9 29,600 .2 7.6

08470500 05/24/2006 09:30 27.0 28,400 .1 7.6

08470500 05/24/2006 09:45 27.1 27,000 .1 7.6

08470500 05/24/2006 10:00 27.1 27,100 .1 7.6

08470500 05/24/2006 10:15 27.0 28,400 .1 7.6

08470500 05/24/2006 10:30 27.0 28,800 .1 7.4

08470500 05/24/2006 10:45 26.9 29,700 .1 7.4

08470500 05/24/2006 11:00 26.9 29,300 .1 7.5

08470500 05/24/2006 11:15 27.0 28,600 .1 7.5

08470500 05/24/2006 11:30 27.0 28,900 .1 7.5

08470500 05/24/2006 11:45 27.0 28,400 .1 7.6

08470500 05/24/2006 12:00 27.0 28,300 .1 7.6

08470500 05/24/2006 12:15 27.1 26,900 .1 7.6

08470500 05/24/2006 12:30 27.0 28,100 .1 7.6

08470500 05/24/2006 12:45 27.0 27,300 .1 7.5

08470500 05/24/2006 13:00 27.1 26,300 .1 7.6

08470500 05/24/2006 13:15 27.0 28,300 .1 7.6

Station 08470520 February data-collection period

08470520 02/22/2006 12:00 17.2 55,000 .8 8.0

08470520 02/22/2006 12:15 17.2 55,000 .8 8.0

08470520 02/22/2006 12:30 17.2 55,000 .8 8.1

08470520 02/22/2006 12:45 17.1 55,000 .8 8.1

08470520 02/22/2006 13:00 17.2 55,000 .8 8.1

08470520 02/22/2006 13:15 17.2 55,100 .8 8.1

08470520 02/22/2006 13:30 17.2 55,100 .8 8.1

08470520 02/22/2006 13:45 17.2 55,100 .7 8.1

08470520 02/22/2006 14:00 17.2 55,100 .8 8.1

08470520 02/22/2006 14:15 17.2 55,100 .8 8.1

08470520 02/22/2006 14:30 17.2 55,100 .7 8.1

08470520 02/22/2006 14:45 17.2 55,100 .7 8.1

08470520 02/22/2006 15:00 17.3 55,100 .7 8.1

08470520 02/22/2006 15:15 17.3 55,100 .7 8.1

08470520 02/22/2006 15:30 17.3 55,100 .7 8.1

08470520 02/22/2006 15:45 17.3 55,200 .7 8.1

08470520 02/22/2006 16:00 17.3 55,200 .6 8.1

08470520 02/22/2006 16:15 17.4 55,200 .6 8.1

08470520 02/22/2006 16:30 17.4 55,300 .6 8.1

08470520 02/22/2006 16:45 17.4 55,300 .6 8.1

08470520 02/22/2006 17:00 17.4 55,300 .6 8.1

08470520 02/22/2006 17:15 17.4 55,300 .6 8.1

08470520 02/22/2006 17:30 17.4 55,300 .5 8.1

08470520 02/22/2006 17:45 17.4 55,300 .5 8.1

08470520 02/22/2006 18:00 17.4 55,300 .6 8.1

08470520 02/22/2006 18:15 17.4 55,300 .5 8.1

08470520 02/22/2006 18:30 17.4 55,300 .5 8.1

08470520 02/22/2006 18:45 17.4 55,300 .5 8.1

08470520 02/22/2006 19:00 17.4 55,300 .5 8.1

08470520 02/22/2006 19:15 17.4 55,300 .6 8.1

08470520 02/22/2006 19:30 17.4 55,300 .5 8.1

08470520 02/22/2006 19:45 17.4 55,300 .5 8.1

08470520 02/22/2006 20:00 17.4 55,300 .5 8.1

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Station 08470520 February data-collection period—Continued

08470520 02/22/2006 20:15 17.4 55,300 0.5 8.1

08470520 02/22/2006 20:30 17.4 55,300 .4 8.1

08470520 02/22/2006 20:45 17.4 55,300 .5 8.1

08470520 02/22/2006 21:00 17.4 55,300 .5 8.1

08470520 02/22/2006 21:15 17.4 55,300 .4 8.1

08470520 02/22/2006 21:30 17.4 55,300 .5 8.1

08470520 02/22/2006 21:45 17.4 55,300 .5 8.1

08470520 02/22/2006 22:00 17.4 55,200 .4 8.1

08470520 02/22/2006 22:15 17.4 55,200 .4 8.1

08470520 02/22/2006 22:30 17.4 55,200 .4 8.1

08470520 02/22/2006 22:45 17.4 55,200 .5 8.1

08470520 02/22/2006 23:00 17.4 55,200 .5 8.1

08470520 02/22/2006 23:15 17.4 55,200 .5 8.1

08470520 02/22/2006 23:30 17.3 55,100 .5 8.1

08470520 02/22/2006 23:45 17.3 55,100 .5 8.1

08470520 02/23/2006 00:00 17.3 55,100 .5 8.1

08470520 02/23/2006 00:15 17.3 55,000 .5 8.1

08470520 02/23/2006 00:30 17.3 55,000 .5 8.1

08470520 02/23/2006 00:45 17.3 55,000 .5 8.1

08470520 02/23/2006 01:00 17.2 55,000 .5 8.1

08470520 02/23/2006 01:15 17.2 55,000 .5 8.1

08470520 02/23/2006 01:30 17.2 55,000 .6 8.1

08470520 02/23/2006 01:45 17.2 55,000 .5 8.1

08470520 02/23/2006 02:00 17.2 54,900 .5 8.1

08470520 02/23/2006 02:15 17.2 54,900 .6 8.1

08470520 02/23/2006 02:30 17.2 54,900 .5 8.1

08470520 02/23/2006 02:45 17.1 54,900 .6 8.1

08470520 02/23/2006 03:00 17.1 54,900 .6 8.1

08470520 02/23/2006 03:15 17.1 54,900 .5 8.1

08470520 02/23/2006 03:30 17.1 54,900 .6 8.1

08470520 02/23/2006 03:45 17.1 54,900 .6 8.1

08470520 02/23/2006 04:00 17.2 54,900 .5 8.1

08470520 02/23/2006 04:15 17.2 54,900 .6 8.1

08470520 02/23/2006 04:30 17.2 54,900 .5 8.1

08470520 02/23/2006 04:45 17.1 54,800 .5 8.1

08470520 02/23/2006 05:00 17.1 54,800 .6 8.1

08470520 02/23/2006 05:15 17.2 54,900 .5 8.1

08470520 02/23/2006 05:30 17.2 54,800 .5 8.1

08470520 02/23/2006 05:45 17.1 54,800 .5 8.1

08470520 02/23/2006 06:00 17.2 54,800 .5 8.1

08470520 02/23/2006 06:15 17.1 54,900 .5 8.1

08470520 02/23/2006 06:30 17.2 54,900 .5 8.1

08470520 02/23/2006 06:45 17.2 54,900 .5 8.1

08470520 02/23/2006 07:00 17.2 54,900 .5 8.1

08470520 02/23/2006 07:15 17.2 54,900 .4 8.1

08470520 02/23/2006 07:30 17.2 54,900 .4 8.1

08470520 02/23/2006 07:45 17.1 54,800 .5 8.1

08470520 02/23/2006 08:00 17.2 54,900 .4 8.1

08470520 02/23/2006 08:15 17.2 54,900 .5 8.1

08470520 02/23/2006 08:30 17.2 54,900 .5 8.1

08470520 02/23/2006 08:45 17.2 55,000 .3 8.1

08470520 02/23/2006 09:00 17.3 55,000 .3 8.1

08470520 02/23/2006 09:15 17.2 54,900 .4 8.1

08470520 02/23/2006 09:30 17.2 54,900 .3 8.1

08470520 02/23/2006 09:45 17.2 54,900 .4 8.1

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)
20 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–1.2. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470520 February data-collection period—Continued

08470520 02/23/2006 10:00 17.2 54,900 0.4 8.1

08470520 02/23/2006 10:15 17.2 54,900 .4 8.1

08470520 02/23/2006 10:30 17.2 54,900 .3 8.1

08470520 02/23/2006 10:45 17.2 54,900 .4 8.1

08470520 02/23/2006 11:00 17.2 54,900 .4 8.1

08470520 02/23/2006 11:15 17.2 54,800 .4 8.1

08470520 02/23/2006 11:30 17.2 54,900 .4 8.1

08470520 02/23/2006 11:45 17.1 54,900 .4 8.1

08470520 02/23/2006 12:00 17.1 54,800 .4 8.1

08470520 02/23/2006 12:15 17.2 54,800 .4 8.1

08470520 02/23/2006 12:30 17.2 54,900 .3 8.1

08470520 02/23/2006 12:45 17.2 54,900 .4 8.1

08470520 02/23/2006 13:00 17.2 54,800 .4 8.1

08470520 02/23/2006 13:15 17.2 54,800 .3 8.1

08470520 02/23/2006 13:30 17.2 54,900 .3 8.1

08470520 02/23/2006 13:45 17.2 54,900 .2 8.1

08470520 02/23/2006 14:00 17.2 54,900 .2 8.1

08470520 02/23/2006 14:15 17.2 54,800 .2 8.1

08470520 02/23/2006 14:30 17.1 54,700 .3 8.1

08470520 02/23/2006 14:45 17.1 54,800 .3 8.1

Station 08470520 May data-collection period

08470520 05/23/2006 10:15 26.8 31,700 .2 7.5

08470520 05/23/2006 10:30 26.8 31,800 .2 7.5

08470520 05/23/2006 10:45 26.8 32,600 .1 7.5

08470520 05/23/2006 11:00 26.8 31,900 .1 7.5

08470520 05/23/2006 11:15 26.8 32,100 .1 7.5

08470520 05/23/2006 11:30 26.8 31,200 .1 7.5

08470520 05/23/2006 11:45 26.8 31,500 .1 7.5

08470520 05/23/2006 12:00 26.8 31,200 .1 7.5

08470520 05/23/2006 12:15 26.8 31,100 .1 7.6

08470520 05/23/2006 12:30 26.8 30,900 .1 7.6

08470520 05/23/2006 12:45 26.8 31,000 .1 7.6

08470520 05/23/2006 13:00 26.8 30,400 .1 7.6

08470520 05/23/2006 13:15 26.8 30,400 .1 7.6

08470520 05/23/2006 13:30 26.8 30,500 .1 7.6

08470520 05/23/2006 13:45 26.8 30,100 .1 7.6

08470520 05/23/2006 14:00 26.8 30,200 .1 7.6

08470520 05/23/2006 14:15 26.8 30,400 .1 7.6

08470520 05/23/2006 14:30 26.8 30,300 .1 7.6

08470520 05/23/2006 14:45 26.8 30,400 .1 7.6

08470520 05/23/2006 15:00 26.8 30,300 .1 7.6

08470520 05/23/2006 15:15 26.8 29,500 .1 7.5

08470520 05/23/2006 15:30 26.8 30,800 .1 7.6

08470520 05/23/2006 15:45 26.8 30,800 .1 7.6

08470520 05/23/2006 16:00 26.8 30,900 .1 7.6

08470520 05/23/2006 16:15 26.8 30,700 .1 7.6

08470520 05/23/2006 16:30 26.7 32,500 .1 7.5

08470520 05/23/2006 16:45 26.7 32,300 .1 7.5

08470520 05/23/2006 17:00 26.7 32,700 .1 7.5

08470520 05/23/2006 17:15 26.7 32,200 .1 7.5

08470520 05/23/2006 17:30 26.7 33,300 .1 7.5

08470520 05/23/2006 17:45 26.7 33,500 .1 7.5

08470520 05/23/2006 18:00 26.7 32,400 .1 7.5

08470520 05/23/2006 18:15 26.7 32,000 .1 7.5

08470520 05/23/2006 18:30 26.7 32,800 .1 7.5

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Station 08470520 May data-collection period—Continued

08470520 05/23/2006 18:45 26.8 31,800 0.1 7.5

08470520 05/23/2006 19:00 26.7 32,500 .1 7.5

08470520 05/23/2006 19:15 26.7 32,800 .1 7.5

08470520 05/23/2006 19:30 26.7 31,900 .1 7.5

08470520 05/23/2006 19:45 26.7 32,400 .1 7.5

08470520 05/23/2006 20:00 26.7 33,600 .1 7.5

08470520 05/23/2006 20:15 26.7 33,300 .1 7.5

08470520 05/23/2006 20:30 26.8 32,100 .1 7.5

08470520 05/23/2006 20:45 26.8 32,100 .1 7.5

08470520 05/23/2006 21:00 26.7 32,200 .1 7.5

08470520 05/23/2006 21:15 26.8 31,800 .1 7.6

08470520 05/23/2006 21:30 26.7 32,100 .1 7.6

08470520 05/23/2006 21:45 26.7 32,300 .1 7.5

08470520 05/23/2006 22:00 26.7 32,300 .1 7.5

08470520 05/23/2006 22:15 26.7 32,700 .1 7.5

08470520 05/23/2006 22:30 26.7 33,500 .1 7.5

08470520 05/23/2006 22:45 26.7 33,500 .1 7.5

08470520 05/23/2006 23:00 26.6 34,200 .1 7.5

08470520 05/23/2006 23:15 26.6 34,400 .1 7.5

08470520 05/23/2006 23:30 26.6 34,600 .1 7.5

08470520 05/23/2006 23:45 26.6 34,700 .1 7.5

08470520 05/24/2006 00:00 26.6 35,900 .1 7.5

08470520 05/24/2006 00:15 26.6 35,400 .1 7.5

08470520 05/24/2006 00:30 26.6 36,000 .1 7.5

08470520 05/24/2006 00:45 26.6 36,100 .1 7.5

08470520 05/24/2006 01:00 26.7 32,700 .1 7.6

08470520 05/24/2006 01:15 26.7 32,000 .1 7.6

08470520 05/24/2006 01:30 26.7 31,100 .1 7.6

08470520 05/24/2006 01:45 26.7 32,200 .1 7.6

08470520 05/24/2006 02:00 26.7 32,500 .1 7.6

08470520 05/24/2006 02:15 26.7 32,300 .1 7.6

08470520 05/24/2006 02:30 26.7 32,500 .1 7.6

08470520 05/24/2006 02:45 26.7 32,100 .1 7.6

08470520 05/24/2006 03:00 26.6 32,300 .1 7.6

08470520 05/24/2006 03:15 26.7 32,200 .1 7.6

08470520 05/24/2006 03:30 26.7 32,100 .1 7.6

08470520 05/24/2006 03:45 26.6 32,500 .1 7.6

08470520 05/24/2006 04:00 26.7 31,600 .1 7.6

08470520 05/24/2006 04:15 26.7 32,700 .1 7.6

08470520 05/24/2006 04:30 26.7 32,600 .1 7.6

08470520 05/24/2006 04:45 26.7 32,800 .1 7.6

08470520 05/24/2006 05:00 26.6 33,600 .1 7.6

08470520 05/24/2006 05:15 26.6 34,400 .1 7.6

08470520 05/24/2006 05:30 26.5 35,800 .1 7.5

08470520 05/24/2006 05:45 26.4 38,400 .1 7.5

08470520 05/24/2006 06:00 26.5 36,000 .1 7.5

08470520 05/24/2006 06:15 26.4 37,300 .1 7.5

08470520 05/24/2006 06:30 26.4 37,600 .1 7.5

08470520 05/24/2006 06:45 26.3 40,300 0 7.5

08470520 05/24/2006 07:00 26.3 40,100 .1 7.5

08470520 05/24/2006 07:15 26.3 40,300 .1 7.5

08470520 05/24/2006 07:30 26.2 41,600 .1 7.5

08470520 05/24/2006 07:45 26.2 41,800 .1 7.6

08470520 05/24/2006 08:00 26.2 41,800 .1 7.5

08470520 05/24/2006 08:15 26.2 41,900 .1 7.6

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)
Appendix 1 21

Appendix 1–1.2. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470520 May data-collection period—Continued

08470520 05/24/2006 08:30 26.2 41,700 0.1 7.6

08470520 05/24/2006 08:45 26.2 41,700 .1 7.6

08470520 05/24/2006 09:00 26.3 40,500 .1 7.6

08470520 05/24/2006 09:15 27.0 27,900 1.8 7.8

08470520 05/24/2006 09:30 26.9 29,400 1.2 7.8

08470520 05/24/2006 09:45 26.8 29,500 .6 7.8

08470520 05/24/2006 10:00 26.7 30,800 .1 7.8

08470520 05/24/2006 10:15 27.0 27,700 .5 7.8

08470520 05/24/2006 10:30 26.9 28,300 .3 7.8

08470520 05/24/2006 10:45 26.8 29,600 .1 7.8

08470520 05/24/2006 11:00 26.9 29,200 .1 7.8

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Station 08470520 May data-collection period—Continued

08470520 05/24/2006 11:15 26.8 30,100 0.1 7.8

08470520 05/24/2006 11:30 26.9 28,600 .1 7.7

08470520 05/24/2006 11:45 26.9 28,400 .1 7.7

08470520 05/24/2006 12:00 26.9 28,700 .1 7.7

08470520 05/24/2006 12:15 26.9 28,400 .1 7.7

08470520 05/24/2006 12:30 26.9 28,500 .1 7.7

08470520 05/24/2006 12:45 26.9 28,500 .1 7.7

08470520 05/24/2006 13:00 27.0 27,800 .1 7.7

08470520 05/24/2006 13:15 27.0 27,000 .1 7.7

08470520 05/24/2006 13:30 27.1 26,400 .1 7.7

USGS

station

no.

Date and

time

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

units)

Appendix 1–1.3. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using sediment traps.

[mg/m2/hr, milligrams per square meter per hour; --, not sampled; values manually rounded] 

USGS

station no.

Date and

time

Total

nonfilterable

 residue 

(mg/m2

/hr)

Ignition

loss from 

nonfilterable

residue

(mg/m2

/hr)

Total

carbon

suspended

sediment

(mg/m2

/hr)

Particulate

nitrogen

suspended

in water

(mg/m2

/hr)

08470450 02/24/2006 14:00 34,690 5,900 571.0 30.0

08470450 02/24/2006 14:05 32,610 5,190 -- --

08470460 02/24/2006 13:00 6,682 1,170 59.9 4.0

08470460 02/24/2006 13:05 8,368 1,810 -- --

08470460 05/24/2006 08:00 25,050 4,320 -- --

08470460 05/24/2006 08:05 23,750 4,530 -- --

08470500 02/24/2006 12:00 1,521 266 30.8 2.0

08470500 02/24/2006 12:05 1,285 270 -- --

08470520 02/24/2006 11:00 1,237 169 187.0 10.0

08470520 02/24/2006 11:05 1,442 308 -- --

08470520 05/24/2006 07:00 2,525 498 -- --

08470520 05/24/2006 07:05 2,555 477 -- --
22 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–1.4a. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using environmental discretesample analysis, February 2006.

[ft, feet; FNMU, formazin nephelometric units; mmHg, millimeters of mercury; mg/L, milligrams per liter; --, not sampled; E, estimated; PSU, practical salinity 

units; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; CaCO3, calcium carbonate; N, nitrogen; NH4, ammonia; NO3, nitrate; P, 

phosphorus; μg/L, micrograms per liter; <, less than] 

Constituent

08470450 08470460 08470500 08470520

02/22/2006

 17:00

02/23/2006

 11:00

02/22/2006

 16:00

02/23/2006

 10:00

02/22/2006

 15:00

02/23/2006

 09:00

02/22/2006

 14:30

02/23/2006

 08:00

Sampling depth (ft) 4 4 14 14 14 14 14 14

Turbidity (FNMU) 210.0 120.0 22.0 15.0 8.0 9.4 6.2 6.4

Barometric pressure (mmHg) 762 762 761 762 760 760 762 762

Carbon dioxide (mg/L) -- -- -- -- -- -- -- --

Dissolved oxygen (mg/L) 8.1 6.7 E.8 E.5 E1.0 E1.2 E.7 E.4

Dissolved oxygen (percent of saturation) 89 76 E10 E6 E13 E15 E9 E5

pH (standard units) 7.7 7.6 8.0 8.0 8.1 8.1 8.1 8.1

Salinity (PSU) 2 2 34 34 35 34 36 36

Specific conductance (μS/cm) 3,620 3,780 51,500 51,700 53,600 52,300 55,100 54,900

Temperature, air (°C) E23.0 E21.0 E23.0 E21.0 E23.0 E21.0 E23.0 E21.0

Temperature, water (°C) 19.2 20.6 16.0 16.1 16.6 16.1 17.0 17.2

Acid neutralizing capacity (mg/L as CaCO3) -- -- -- -- -- -- -- --

Chloride (mg/L) 660 640 16,000 19,000 18,000 19,000 20,000 16,000

Sulfate (mg/L) 640 630 2,600 2,800 2,600 2,700 2,700 2,600

Residue on evaporation dried at 180 °C (mg/L) 2,300 2,400 33,000 34,000 33,000 34,000 36,000 36,000

Fixed nonfilterable residue (mg/L) 74 79 14 10 10 7 8 5

Total nonfilterable residue (mg/L) 100 100 22 14 16 11 12 10

Ignition loss from nonfilterable residue (mg/L) 26.0 21.0 8.4 4.4 5.6 4.4 4.4 4.8

Ammonia plus organic nitrogen (mg/L as N) 1.10 .90 .97 1.20 1.30 .85 .62 .67

Ammonia (mg/L as NH4) .32 .35 .88 .89 .93 .80 .71 .70

Ammonia (mg/L as N) .25 .27 .68 .69 .72 .62 .55 .54

Nitrite plus nitrate (mg/L as N) 5.20 5.10 .26 .48 .86 .36 .46 .27

Organic nitrogen (mg/L) .85 .63 .29 .51 .58 .23 .07 .13

Particulate nitrogen (mg/L) .45 .48 .25 .30 .20 .25 .22 .31

Total nitrogen (mg/L) 6.3 6.0 1.2 1.7 2.2 1.2 1.1 .9

Total nitrogen (mg/L as NO3) 27.9 26.6 5.4 7.4 9.6 5.4 4.8 4.2

Orthophosphate (mg/L) .399 1.660 .043 .227 .399 .399 .175 .267

Orthophosphate (mg/L as P) .130 .540 .014 .074 .130 .130 .057 .087

Phosphate (mg/L) .560 .550 .094 .088 .120 .150 .088 .088

Phosphorus (mg/L) E.34 E.39 E.20 E.24 E.24 E.24 E.18 E.16

Carbon (inorganic plus organic) suspended 

sediment (mg/L)

6.0 5.5 1.8 1.6 1.1 1.1 1.0 1.1

Organic carbon, filtered (mg/L) 3.4 E3.2 5.7 E5.3 5.6 E5.5 5.4 E4.1

Organic carbon, unfiltered (mg/L) 3.9 4.0 5.7 6.2 5.6 5.6 5.6 5.6

Biochemical oxygen demand (mg/L) 2.9 2.9 <2.0 <2.0 2.2 <2.0 <2.0 <2.0

Chlorophyll a (μg/L) E19.0 E18.0 <5.00 -- <5.00 <5.00 <5.00 <5.00

Pheophytin a (μg/L) E6.00 <5.00 <5.00 -- <5.00 <5.00 <5.00 <5.00
Appendix 1 23

Appendix 1–1.4b. Data collected at near-bottom depth of the Arroyo Colorado near Rio Hondo, Texas, using environmental discretesample analysis, May 2006.

[ft, feet; FNMU, formazin nephelometric units; mmHg, millimeters of mercury; mg/L, milligrams per liter; --, not sampled; E, estimated; PSU, practical salinity 

units; μS/cm, microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; CaCO3, calcium carbonate; N, nitrogen; NH4, ammonia; NO3, nitrate; P, 

phosphorus; μg/l, micrograms per liter; <, less than]

Constituent

08470450 08470460 08470500 08470520

05/23/2006

11:00

05/24/2006

11:00

05/23/2006

12:00

05/24/2006

10:00

05/23/2006

13:00

05/24/2006

09:00

05/23/2006

14:00

05/24/2006

07:00

Sampling depth (ft) 4 4 10 10 10 10 10 10

Turbidity (FNMU) 110 140 38 36 12 52 8.4 17

Barometric pressure (mmHg) 760 760 760 762 761 762 760 760

Carbon dioxide (mg/L) 4.5 3.9 1.5 .7 2.5 1.3 8.7 --

Dissolved oxygen (mg/L) 5.3 4.8 E.6 E.1 E.8 E.1 E.3 E.1

Dissolved oxygen (percent of saturation) 69 63 -- -- -- -- -- --

pH (standard units) 8.0 8.0 8.4 8.7 8.1 8.4 7.5 9.5

Salinity (PSU) 2 2 20 22 26 19 15 29

Specific conductance (μS/cm) 4,310 4,350 31,900 35,300 41,100 29,900 24,600 45,000

Temperature, air (°C) 32.8 31.1 33.9 28.9 33.9 28.9 33.9 23.9

Temperature, water (°C) 28.1 28.2 26.9 26.7 26.3 26.9 27.0 25.5

Acid neutralizing capacity (mg/L as CaCO3) 210 210 180 180 170 170 160 --

Chloride (mg/L) 830 860 13,000 10,000 11,000 11,000 13,000 12,000

Sulfate (mg/L) 870 920 2,100 1,900 1,900 1,900 2,100 2,100

Residue on evaporation dried at 180 °C (mg/L) 2,700 2,800 22,000 20,000 19,000 18,000 18,000 21,000

Fixed nonfilterable residue (mg/L) 81 82 10 18 6 15 4 12

Total nonfilterable residue (mg/L) E100 E110 E18 E27 E16 E28 E13 E26

Ignition loss from nonfilterable residue (mg/L) E19.0 E28.0 E7.6 E8.8 E10.0 E13.0 E8.8 E14.0

Ammonia plus organic nitrogen (mg/L as N) 1.10 1.20 1.70 2.20 1.50 1.80 1.60 1.40

Ammonia (mg/L as NH4) .22 .15 1.80 1.67 1.16 1.15 1.24 .91

Ammonia (mg/L as N) .17 .12 1.40 1.30 .90 .89 .96 .71

Nitrite plus nitrate (mg/L as N) 4.10 1.80 .22 .10 .44 .65 .02 1.70

Organic nitrogen (mg/L) .93 1.10 .30 .90 .60 .91 .64 .69

Particulate nitrogen (mg/L) -- -- -- -- -- -- -- --

Total nitrogen (mg/L) 5.2 3.0 1.9 2.3 1.9 2.4 1.6 3.1

Total nitrogen (mg/L as NO3) 23.0 13.3 8.5 10.2 8.6 10.8 7.2 13.7

Orthophosphate (mg/L) 1.870 1.870 1.130 1.200 .221 1.070 1.320 .705

Orthophosphate (mg/L as P) .610 .610 .370 .390 .072 .350 .430 .230

Phosphate (mg/L) -- -- -- -- -- -- -- --

Phosphorus (mg/L) .64 .56 .54 .54 .37 .45 .36 .40

Carbon (inorganic plus organic) suspended sediment 

(mg/L)

-- -- -- -- -- -- -- --

Organic carbon, filtered (mg/L) 4.4 4.3 5.0 4.7 4.8 5.6 5.3 6.4

Organic carbon, unfiltered (mg/L) 4.7 4.6 5.5 5.4 5.5 6.2 9.2 7.7

Biochemical oxygen demand (mg/L) 3.3 3.2 5.0 4.5 2.4 E8.8 E8.0 E8.6

Chlorophyll a (μg/L) E42.0 E35.0 E13.0 E5.70 E16.0 E57.0 E140 E93.0

Pheophytin a (μg/L) E18.0 E19.0 E3.30 E5.30 <3.00 <3.00 E6.90 E16.0
24 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–2.1. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using algal productivity methods.

[mg O2/m3/day, milligrams of oxygen per cubic meter per day; negative value signifies a deficit of oxygen and positive value signifies accumulation of oxygen; 

values manually rounded.]

USGS

station no. Date Data-collectionperiod

Gross primary productivity 

(mg O2/m3

/day)

Net primary productivity

(mg O2/m3

/day)

Respiration 

(mg O2/m3

/day)

08470460 02/22/2006 February 9,068 6,547 2,521

08470460 05/23/2006 May 16,452 12,875 3,576

08470500 02/22/2006 February 8,243 4,529 3,714

08470500 05/23/2006 May 35,660 31,820 3,840

Appendix 1–2.2. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors.

[°C, degrees Celsius; μS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L, milligrams per liter. Dissolved oxygen values less than 2.0 mg/L reported 

here to show resolution in a low dissolved oxygen environment, rather than set all values to <2.0 mg/L; zero values should be interpreted as <0.1 mg/L] 

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)

Station 08470450 February data-collection period

08470450 02/22/2006 10:30 17.8 3,540 7.8 7.6

08470450 02/22/2006 10:45 17.9 3,540 7.8 7.6

08470450 02/22/2006 11:00 18.1 3,480 7.9 7.7

08470450 02/22/2006 11:15 18.1 3,510 7.9 7.7

08470450 02/22/2006 11:30 18.1 3,540 7.8 7.7

08470450 02/22/2006 11:45 18.3 3,480 7.8 7.7

08470450 02/22/2006 12:00 18.2 3,530 7.9 7.7

08470450 02/22/2006 12:15 18.3 3,540 7.9 7.7

08470450 02/22/2006 12:30 18.4 3,540 7.9 7.7

08470450 02/22/2006 12:45 18.4 3,540 8.0 7.7

08470450 02/22/2006 13:00 18.6 3,540 8.0 7.7

08470450 02/22/2006 13:15 18.6 3,540 8.0 7.7

08470450 02/22/2006 13:30 18.7 3,540 8.0 7.7

08470450 02/22/2006 13:45 18.7 3,560 8.1 7.7

08470450 02/22/2006 14:00 18.8 3,540 8.0 7.7

08470450 02/22/2006 14:15 19.0 3,540 8.1 7.7

08470450 02/22/2006 14:30 19.0 3,560 8.1 7.7

08470450 02/22/2006 14:45 19.1 3,560 8.1 7.7

08470450 02/22/2006 15:00 19.4 3,500 8.2 7.7

08470450 02/22/2006 15:15 19.5 3,520 8.1 7.7

08470450 02/22/2006 15:30 19.6 3,500 8.2 7.8

08470450 02/22/2006 15:45 19.5 3,540 8.2 7.7

08470450 02/22/2006 16:00 19.7 3,520 8.2 7.8

08470450 02/22/2006 16:15 19.7 3,540 8.2 7.8

08470450 02/22/2006 16:30 19.8 3,570 8.2 7.7

08470450 02/22/2006 16:45 19.8 3,550 8.5 7.8

08470450 02/22/2006 17:00 19.5 3,640 8.2 7.7

08470450 02/22/2006 17:15 19.5 3,640 8.2 7.7

08470450 02/22/2006 17:30 19.5 3,640 8.1 7.7

08470450 02/22/2006 17:45 19.6 3,650 8.1 7.7

08470450 02/22/2006 18:00 19.6 3,650 8.1 7.7

08470450 02/22/2006 18:15 19.6 3,660 8.1 7.7

08470450 02/22/2006 18:30 19.6 3,670 8.1 7.7

08470450 02/22/2006 18:45 19.6 3,710 8.1 7.7

08470450 02/22/2006 19:00 19.6 3,690 8.0 7.7

08470450 02/22/2006 19:15 19.6 3,810 8.0 7.7

08470450 02/22/2006 19:30 19.6 3,790 8.0 7.7

08470450 02/22/2006 19:45 19.6 3,800 8.0 7.7

08470450 02/22/2006 20:00 19.6 3,800 7.9 7.7

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)

Station 08470450 February data-collection period—Continued

08470450 02/22/2006 20:15 19.6 3,750 7.9 7.7

08470450 02/22/2006 20:30 19.6 3,750 7.9 7.7

08470450 02/22/2006 20:45 19.7 3,760 7.8 7.7

08470450 02/22/2006 21:00 19.7 3,820 7.8 7.7

08470450 02/22/2006 21:15 19.7 3,760 7.8 7.7

08470450 02/22/2006 21:30 19.7 3,740 7.7 7.7

08470450 02/22/2006 21:45 19.7 3,750 7.7 7.7

08470450 02/22/2006 22:00 19.7 3,790 7.7 7.7

08470450 02/22/2006 22:15 19.8 3,820 7.6 7.7

08470450 02/22/2006 22:30 19.8 3,770 7.6 7.7

08470450 02/22/2006 22:45 19.8 3,740 7.6 7.7

08470450 02/22/2006 23:00 19.8 3,740 7.5 7.7

08470450 02/22/2006 23:15 19.8 3,740 7.5 7.7

08470450 02/22/2006 23:30 19.9 3,740 7.4 7.7

08470450 02/22/2006 23:45 19.9 3,740 7.4 7.7

08470450 02/23/2006 00:00 20.0 3,750 7.4 7.7

08470450 02/23/2006 00:15 20.0 3,750 7.3 7.7

08470450 02/23/2006 00:30 20.0 3,750 7.3 7.7

08470450 02/23/2006 00:45 20.1 3,760 7.2 7.7

08470450 02/23/2006 01:00 20.1 3,760 7.2 7.7

08470450 02/23/2006 01:15 20.2 3,760 7.2 7.7

08470450 02/23/2006 01:30 20.2 3,760 7.2 7.7

08470450 02/23/2006 01:45 20.3 3,760 7.1 7.7

08470450 02/23/2006 02:00 20.3 3,760 7.1 7.7

08470450 02/23/2006 02:15 20.4 3,760 7.1 7.7

08470450 02/23/2006 02:30 20.4 3,760 7.0 7.7

08470450 02/23/2006 02:45 20.4 3,760 7.0 7.7

08470450 02/23/2006 03:00 20.5 3,750 7.0 7.7

08470450 02/23/2006 03:15 20.5 3,750 7.0 7.7

08470450 02/23/2006 03:30 20.6 3,740 7.0 7.7

08470450 02/23/2006 03:45 20.6 3,740 7.0 7.7

08470450 02/23/2006 04:00 20.6 3,740 6.9 7.7

08470450 02/23/2006 04:15 20.7 3,730 6.9 7.7

08470450 02/23/2006 04:30 20.7 3,730 6.9 7.7

08470450 02/23/2006 04:45 20.7 3,730 6.9 7.7

08470450 02/23/2006 05:00 20.7 3,720 6.9 7.7

08470450 02/23/2006 05:15 20.7 3,720 6.8 7.7

08470450 02/23/2006 05:30 20.8 3,720 6.8 7.7

08470450 02/23/2006 05:45 20.8 3,720 6.8 7.7
Appendix 1 25

Appendix 1–2.2. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470450 February data-collection period—Continued

08470450 02/23/2006 06:00 20.8 3,730 6.8 7.7

08470450 02/23/2006 06:15 20.8 3,730 6.8 7.7

08470450 02/23/2006 06:30 20.8 3,730 6.8 7.7

08470450 02/23/2006 06:45 20.8 3,740 6.8 7.7

08470450 02/23/2006 07:00 20.8 3,740 6.7 7.7

08470450 02/23/2006 07:15 20.9 3,740 6.7 7.7

08470450 02/23/2006 07:30 20.9 3,740 6.6 7.7

08470450 02/23/2006 07:45 20.9 3,750 6.7 7.7

08470450 02/23/2006 08:00 20.9 3,750 6.6 7.7

08470450 02/23/2006 08:15 20.9 3,750 6.6 7.7

08470450 02/23/2006 08:30 20.9 3,760 6.6 7.7

08470450 02/23/2006 08:45 21.0 3,760 6.6 7.7

08470450 02/23/2006 09:00 21.0 3,760 6.6 7.7

08470450 02/23/2006 09:15 21.0 3,770 6.6 7.7

08470450 02/23/2006 09:30 21.0 3,770 6.6 7.7

08470450 02/23/2006 09:45 21.0 3,780 6.6 7.7

08470450 02/23/2006 10:00 21.1 3,780 6.7 7.7

08470450 02/23/2006 10:15 21.0 3,780 6.6 7.7

08470450 02/23/2006 10:30 21.0 3,790 6.7 7.7

08470450 02/23/2006 10:45 21.0 3,790 6.7 7.7

08470450 02/23/2006 11:00 21.0 3,790 6.6 7.7

08470450 02/23/2006 11:15 21.0 3,790 6.7 7.7

08470450 02/23/2006 11:30 21.0 3,790 6.7 7.7

08470450 02/23/2006 11:45 20.9 3,800 6.8 7.7

08470450 02/23/2006 12:00 20.9 3,800 6.7 7.7

08470450 02/23/2006 12:15 20.9 3,800 6.8 7.7

08470450 02/23/2006 12:30 20.9 3,800 6.8 7.7

08470450 02/23/2006 12:45 20.9 3,800 6.8 7.7

08470450 02/23/2006 13:00 20.9 3,810 6.8 7.7

Station 08470450 May data-collection period

08470450 05/23/2006 11:45 28.2 4,300 5.3 7.7

08470450 05/23/2006 12:00 28.2 4,300 5.3 7.7

08470450 05/23/2006 12:15 28.3 4,300 5.5 7.7

08470450 05/23/2006 12:30 28.3 4,300 5.5 7.7

08470450 05/23/2006 12:45 28.4 4,310 5.4 7.6

08470450 05/23/2006 13:00 28.4 4,310 5.5 7.6

08470450 05/23/2006 13:15 28.4 4,310 5.5 7.7

08470450 05/23/2006 13:30 28.4 4,310 5.6 7.7

08470450 05/23/2006 13:45 28.5 4,310 5.7 7.7

08470450 05/23/2006 14:00 28.5 4,320 5.7 7.7

08470450 05/23/2006 14:15 28.6 4,320 5.9 7.7

08470450 05/23/2006 14:30 28.7 4,320 6.0 7.7

08470450 05/23/2006 14:45 28.7 4,320 6.0 7.7

08470450 05/23/2006 15:00 28.8 4,320 6.1 7.7

08470450 05/23/2006 15:15 28.9 4,320 6.2 7.7

08470450 05/23/2006 15:30 28.9 4,320 6.2 7.7

08470450 05/23/2006 15:45 29.0 4,320 6.3 7.7

08470450 05/23/2006 16:00 29.1 4,320 6.4 7.7

08470450 05/23/2006 16:15 29.2 4,310 6.4 7.7

08470450 05/23/2006 16:30 29.2 4,310 6.4 7.7

08470450 05/23/2006 16:45 29.2 4,310 6.4 7.7

08470450 05/23/2006 17:00 29.2 4,310 6.4 7.7

08470450 05/23/2006 17:15 29.3 4,320 6.5 7.8

08470450 05/23/2006 17:30 29.3 4,320 6.5 7.8

08470450 05/23/2006 17:45 29.4 4,320 6.6 7.8

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)

Station 08470450 May data-collection period—Continued

08470450 05/23/2006 18:00 29.4 4,320 6.7 7.8

08470450 05/23/2006 18:15 29.5 4,320 6.7 7.8

08470450 05/23/2006 18:30 29.6 4,320 6.8 7.8

08470450 05/23/2006 18:45 29.6 4,320 6.8 7.8

08470450 05/23/2006 19:00 29.6 4,320 6.8 7.8

08470450 05/23/2006 19:15 29.6 4,320 6.9 7.8

08470450 05/23/2006 19:30 29.6 4,320 6.9 7.8

08470450 05/23/2006 19:45 29.5 4,320 6.9 7.8

08470450 05/23/2006 20:00 29.5 4,320 6.9 7.8

08470450 05/23/2006 20:15 29.4 4,320 6.8 7.8

08470450 05/23/2006 20:30 29.4 4,320 6.8 7.8

08470450 05/23/2006 20:45 29.3 4,320 6.7 7.8

08470450 05/23/2006 21:00 29.2 4,310 6.7 7.8

08470450 05/23/2006 21:15 29.2 4,310 6.7 7.8

08470450 05/23/2006 21:30 29.1 4,300 6.6 7.8

08470450 05/23/2006 21:45 29.1 4,290 6.5 7.8

08470450 05/23/2006 22:00 29.0 4,280 6.5 7.7

08470450 05/23/2006 22:15 29.0 4,270 6.5 7.7

08470450 05/23/2006 22:30 29.0 4,270 6.4 7.7

08470450 05/23/2006 22:45 29.0 4,260 6.4 7.7

08470450 05/23/2006 23:00 29.0 4,260 6.4 7.7

08470450 05/23/2006 23:15 28.9 4,250 6.4 7.7

08470450 05/23/2006 23:30 28.9 4,250 6.3 7.7

08470450 05/23/2006 23:45 28.9 4,240 6.3 7.7

08470450 05/24/2006 00:00 28.8 4,240 6.2 7.7

08470450 05/24/2006 00:15 28.8 4,240 6.2 7.7

08470450 05/24/2006 00:30 28.7 4,240 6.2 7.7

08470450 05/24/2006 00:45 28.7 4,240 6.2 7.7

08470450 05/24/2006 01:00 28.6 4,240 6.2 7.7

08470450 05/24/2006 01:15 28.6 4,240 6.1 7.7

08470450 05/24/2006 01:30 28.6 4,230 6.1 7.7

08470450 05/24/2006 01:45 28.5 4,230 6.2 7.7

08470450 05/24/2006 02:00 28.5 4,230 6.1 7.7

08470450 05/24/2006 02:15 28.5 4,230 6.0 7.7

08470450 05/24/2006 02:30 28.5 4,230 6.0 7.7

08470450 05/24/2006 02:45 28.5 4,230 5.9 7.7

08470450 05/24/2006 03:00 28.5 4,230 5.8 7.7

08470450 05/24/2006 03:15 28.5 4,240 5.8 7.7

08470450 05/24/2006 03:30 28.5 4,240 5.7 7.7

08470450 05/24/2006 03:45 28.5 4,240 5.6 7.7

08470450 05/24/2006 04:00 28.5 4,250 5.6 7.7

08470450 05/24/2006 04:15 28.5 4,260 5.5 7.7

08470450 05/24/2006 04:30 28.4 4,270 5.4 7.7

08470450 05/24/2006 04:45 28.4 4,280 5.3 7.7

08470450 05/24/2006 05:00 28.4 4,290 5.2 7.7

08470450 05/24/2006 05:15 28.4 4,290 5.2 7.7

08470450 05/24/2006 05:30 28.4 4,300 5.1 7.7

08470450 05/24/2006 05:45 28.4 4,310 5.0 7.7

08470450 05/24/2006 06:00 28.4 4,320 5.0 7.7

08470450 05/24/2006 06:15 28.4 4,330 4.9 7.7

08470450 05/24/2006 06:30 28.4 4,340 4.9 7.7

08470450 05/24/2006 06:45 28.4 4,340 4.9 7.7

08470450 05/24/2006 07:00 28.4 4,350 4.9 7.7

08470450 05/24/2006 07:15 28.4 4,350 4.9 7.7

08470450 05/24/2006 07:30 28.3 4,350 4.9 7.7

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)
26 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–2.2. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470450 May data-collection period—Continued

08470450 05/24/2006 07:45 28.3 4,360 4.9 7.7

08470450 05/24/2006 08:00 28.3 4,360 4.9 7.7

08470450 05/24/2006 08:15 28.2 4,360 4.8 7.7

08470450 05/24/2006 08:30 28.2 4,370 4.7 7.7

08470450 05/24/2006 08:45 28.2 4,370 4.7 7.7

08470450 05/24/2006 09:00 28.2 4,380 4.8 7.7

08470450 05/24/2006 09:15 28.1 4,380 4.8 7.7

08470450 05/24/2006 09:30 28.1 4,390 4.8 7.7

08470450 05/24/2006 09:45 28.1 4,390 4.8 7.7

08470450 05/24/2006 10:00 28.1 4,390 4.8 7.7

08470450 05/24/2006 10:15 28.1 4,390 4.8 7.7

08470450 05/24/2006 10:30 28.1 4,380 4.8 7.7

08470450 05/24/2006 10:45 28.1 4,380 4.8 7.7

08470450 05/24/2006 11:00 28.1 4,370 4.9 7.7

08470450 05/24/2006 11:15 28.1 4,370 5.0 7.7

08470450 05/24/2006 11:30 28.2 4,360 5.0 7.7

08470450 05/24/2006 11:45 28.2 4,360 5.1 7.7

08470450 05/24/2006 12:00 28.4 4,360 5.2 7.7

08470450 05/24/2006 12:15 28.4 4,350 5.2 7.7

08470450 05/24/2006 12:30 28.5 4,340 5.3 7.7

08470450 05/24/2006 12:45 28.5 4,340 5.4 7.7

Station 08470460 February data-collection period

08470460 02/22/2006 09:45 17.6 4,380 8.2 7.6

08470460 02/22/2006 10:00 17.7 4,400 8.2 7.7

08470460 02/22/2006 10:15 17.8 4,440 8.2 7.7

08470460 02/22/2006 10:30 17.9 4,590 8.1 7.7

08470460 02/22/2006 10:45 18.0 4,680 8.1 7.7

08470460 02/22/2006 11:00 18.1 4,850 8.2 7.7

08470460 02/22/2006 11:15 18.2 5,080 8.1 7.7

08470460 02/22/2006 11:30 18.3 5,310 8.2 7.7

08470460 02/22/2006 11:45 18.4 5,430 8.2 7.7

08470460 02/22/2006 12:00 18.4 5,860 8.2 7.7

08470460 02/22/2006 12:15 18.6 6,240 8.2 7.7

08470460 02/22/2006 12:30 18.7 6,930 8.1 7.7

08470460 02/22/2006 12:45 19.0 7,690 8.0 7.7

08470460 02/22/2006 13:00 18.6 11,500 7.6 7.7

08470460 02/22/2006 13:15 18.6 13,000 7.3 7.7

08470460 02/22/2006 13:30 18.6 16,000 7.0 7.6

08470460 02/22/2006 13:45 18.1 22,000 6.1 7.6

08470460 02/22/2006 14:00 18.1 22,900 5.7 7.6

08470460 02/22/2006 14:15 18.6 21,800 6.2 7.7

08470460 02/22/2006 14:30 18.4 24,100 5.3 7.7

08470460 02/22/2006 14:45 18.1 25,400 5.2 7.7

08470460 02/22/2006 15:00 18.2 29,000 5.3 7.7

08470460 02/22/2006 15:15 18.7 26,500 5.7 7.7

08470460 02/22/2006 15:30 18.2 28,600 5.5 7.7

08470460 02/22/2006 15:45 19.2 25,200 5.8 7.7

08470460 02/22/2006 16:00 18.4 27,600 5.8 7.7

08470460 02/22/2006 16:15 19.0 26,300 5.8 7.7

08470460 02/22/2006 16:30 18.6 27,300 5.1 7.7

08470460 02/22/2006 16:45 19.2 25,400 5.9 7.7

08470460 02/22/2006 17:00 19.3 25,500 6.0 7.8

08470460 02/22/2006 17:15 18.6 24,200 6.1 7.7

08470460 02/22/2006 17:30 19.1 21,800 6.2 7.8

08470460 02/22/2006 17:45 18.6 23,900 5.6 7.7

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)

Station 08470460 February data-collection period—Continued

08470460 02/22/2006 18:00 18.7 22,600 6.2 7.8

08470460 02/22/2006 18:15 18.6 22,600 6.0 7.7

08470460 02/22/2006 18:30 18.8 21,900 5.8 7.7

08470460 02/22/2006 18:45 18.9 20,300 6.2 7.8

08470460 02/22/2006 19:00 19.0 18,900 6.3 7.8

08470460 02/22/2006 19:15 19.0 18,700 6.2 7.7

08470460 02/22/2006 19:30 19.0 19,000 6.1 7.7

08470460 02/22/2006 19:45 19.0 19,400 6.2 7.7

08470460 02/22/2006 20:00 19.0 18,500 6.2 7.7

08470460 02/22/2006 20:15 19.1 17,700 6.2 7.7

08470460 02/22/2006 20:30 19.1 16,900 6.3 7.7

08470460 02/22/2006 20:45 19.1 16,100 6.3 7.7

08470460 02/22/2006 21:00 19.2 15,000 6.5 7.7

08470460 02/22/2006 21:15 19.3 13,600 6.6 7.7

08470460 02/22/2006 21:30 19.3 12,900 6.6 7.7

08470460 02/22/2006 21:45 19.4 12,900 6.6 7.7

08470460 02/22/2006 22:00 19.4 11,900 6.7 7.7

08470460 02/22/2006 22:15 19.4 11,200 6.7 7.7

08470460 02/22/2006 22:30 19.4 10,900 6.8 7.7

08470460 02/22/2006 22:45 19.4 11,200 6.8 7.7

08470460 02/22/2006 23:00 19.5 10,100 6.9 7.7

08470460 02/22/2006 23:15 19.5 10,200 6.8 7.7

08470460 02/22/2006 23:30 19.5 10,700 6.7 7.7

08470460 02/22/2006 23:45 19.6 9,660 6.8 7.7

08470460 02/23/2006 00:00 19.7 8,720 6.8 7.7

08470460 02/23/2006 00:15 19.7 8,560 6.9 7.7

08470460 02/23/2006 00:30 19.7 8,740 6.9 7.7

08470460 02/23/2006 00:45 19.7 8,410 6.9 7.7

08470460 02/23/2006 01:00 19.8 8,160 6.8 7.7

08470460 02/23/2006 01:15 19.8 7,840 6.8 7.7

08470460 02/23/2006 01:30 19.8 7,780 6.9 7.7

08470460 02/23/2006 01:45 19.8 7,960 6.8 7.7

08470460 02/23/2006 02:00 19.8 7,430 6.8 7.7

08470460 02/23/2006 02:15 19.9 7,280 6.9 7.7

08470460 02/23/2006 02:30 19.9 6,990 6.8 7.7

08470460 02/23/2006 02:45 20.0 6,750 6.8 7.7

08470460 02/23/2006 03:00 20.0 6,620 6.8 7.7

08470460 02/23/2006 03:15 20.0 6,600 6.8 7.7

08470460 02/23/2006 03:30 20.1 6,520 6.8 7.7

08470460 02/23/2006 03:45 20.1 6,390 6.7 7.7

08470460 02/23/2006 04:00 20.1 6,300 6.7 7.7

08470460 02/23/2006 04:15 20.2 6,210 6.7 7.7

08470460 02/23/2006 04:30 20.2 6,050 6.7 7.7

08470460 02/23/2006 04:45 20.2 5,880 6.7 7.7

08470460 02/23/2006 05:00 20.2 5,790 6.6 7.7

08470460 02/23/2006 05:15 20.2 5,750 6.7 7.7

08470460 02/23/2006 05:30 20.3 5,660 6.7 7.7

08470460 02/23/2006 05:45 20.3 5,480 6.7 7.7

08470460 02/23/2006 06:00 20.4 5,390 6.6 7.7

08470460 02/23/2006 06:15 20.4 5,150 6.7 7.7

08470460 02/23/2006 06:30 20.4 5,290 6.6 7.7

08470460 02/23/2006 06:45 20.5 5,190 6.6 7.7

08470460 02/23/2006 07:00 20.5 4,990 6.6 7.7

08470460 02/23/2006 07:15 20.6 4,780 6.6 7.7

08470460 02/23/2006 07:30 20.6 4,640 6.7 7.7

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)
Appendix 1 27

Appendix 1–2.2. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470460 February data-collection period—Continued

08470460 02/23/2006 07:45 20.6 4,630 6.6 7.7

08470460 02/23/2006 08:00 20.6 4,780 6.6 7.7

08470460 02/23/2006 08:15 20.6 4,900 6.6 7.7

08470460 02/23/2006 08:30 20.6 5,000 6.7 7.7

08470460 02/23/2006 08:45 20.6 4,880 6.6 7.7

08470460 02/23/2006 09:00 20.5 5,220 6.7 7.7

08470460 02/23/2006 09:15 20.8 4,810 6.8 7.7

08470460 02/23/2006 09:30 20.7 5,010 6.7 7.7

08470460 02/23/2006 09:45 20.8 4,960 6.7 7.7

08470460 02/23/2006 10:00 20.9 4,630 6.8 7.7

08470460 02/23/2006 10:15 20.9 4,310 6.7 7.7

08470460 02/23/2006 10:30 20.8 4,780 6.8 7.7

08470460 02/23/2006 10:45 20.8 4,800 6.8 7.7

08470460 02/23/2006 11:00 20.7 5,000 6.9 7.7

08470460 02/23/2006 11:15 20.8 4,490 6.9 7.7

08470460 02/23/2006 11:30 20.8 4,320 6.9 7.7

08470460 02/23/2006 11:45 20.8 4,190 6.9 7.7

08470460 02/23/2006 12:00 20.8 4,250 7.0 7.7

08470460 02/23/2006 12:15 20.8 4,510 7.1 7.7

08470460 02/23/2006 12:30 20.7 4,790 7.1 7.7

08470460 02/23/2006 12:45 20.8 4,450 7.1 7.7

08470460 02/23/2006 13:00 20.8 4,350 7.2 7.7

08470460 02/23/2006 13:15 20.8 4,410 7.3 7.7

08470460 02/23/2006 13:30 20.8 4,230 7.2 7.7

08470460 02/23/2006 13:45 17.6 4,380 8.2 7.6

Station 08470460 May data-collection period

08470460 05/23/2006 11:15 27.9 5,170 5.6 7.7

08470460 05/23/2006 11:30 27.9 5,270 5.7 7.7

08470460 05/23/2006 11:45 28.0 5,250 5.7 7.7

08470460 05/23/2006 12:00 28.1 5,160 6.0 7.7

08470460 05/23/2006 12:15 28.2 5,260 5.8 7.7

08470460 05/23/2006 12:30 28.2 5,310 5.8 7.7

08470460 05/23/2006 12:45 28.2 5,310 5.9 7.7

08470460 05/23/2006 13:00 28.3 5,350 5.7 7.7

08470460 05/23/2006 13:15 28.4 5,350 5.9 7.7

08470460 05/23/2006 13:30 28.7 5,400 6.2 7.7

08470460 05/23/2006 13:45 28.8 5,380 6.2 7.8

08470460 05/23/2006 14:00 28.7 5,440 6.2 7.7

08470460 05/23/2006 14:15 29.0 5,360 6.4 7.8

08470460 05/23/2006 14:30 28.9 5,510 6.3 7.7

08470460 05/23/2006 14:45 28.8 5,560 6.1 7.7

08470460 05/23/2006 15:00 29.4 5,630 6.6 7.8

08470460 05/23/2006 15:15 28.9 8,210 5.1 7.7

08470460 05/23/2006 15:30 29.0 8,550 5.3 7.7

08470460 05/23/2006 15:45 28.9 9,220 5.3 7.7

08470460 05/23/2006 16:00 28.6 15,000 3.6 7.6

08470460 05/23/2006 16:15 28.8 12,000 4.0 7.6

08470460 05/23/2006 16:30 29.0 12,100 4.4 7.7

08470460 05/23/2006 16:45 28.9 12,000 4.5 7.7

08470460 05/23/2006 17:00 28.7 12,500 4.0 7.6

08470460 05/23/2006 17:15 28.7 14,000 4.1 7.6

08470460 05/23/2006 17:30 29.1 10,800 5.2 7.7

08470460 05/23/2006 17:45 29.1 11,000 5.0 7.7

08470460 05/23/2006 18:00 29.1 10,600 5.4 7.7

08470460 05/23/2006 18:15 29.1 11,800 4.9 7.7

08470460 05/23/2006 18:30 29.1 11,700 5.0 7.7

08470460 05/23/2006 18:45 29.2 11,200 5.3 7.7

08470460 05/23/2006 19:00 29.3 10,800 5.3 7.7

08470460 05/23/2006 19:15 29.8 8,690 6.1 7.8

08470460 05/23/2006 19:30 29.8 8,060 6.3 7.8

08470460 05/23/2006 19:45 29.6 7,170 6.4 7.8

08470460 05/23/2006 20:00 29.6 6,480 6.2 7.8

08470460 05/23/2006 20:15 29.5 6,110 6.4 7.8

08470460 05/23/2006 20:30 29.5 5,940 6.2 7.8

08470460 05/23/2006 20:45 29.4 5,400 6.3 7.8

08470460 05/23/2006 21:00 29.3 5,320 6.2 7.8

08470460 05/23/2006 21:15 29.3 4,860 6.2 7.8

08470460 05/23/2006 21:30 29.3 5,150 6.0 7.8

08470460 05/23/2006 21:45 29.2 5,050 6.0 7.8

08470460 05/23/2006 22:00 29.2 5,180 6.0 7.8

08470460 05/23/2006 22:15 29.1 5,180 6.1 7.8

08470460 05/23/2006 22:30 29.0 5,110 6.1 7.8

08470460 05/23/2006 22:45 29.2 5,620 6.1 7.7

08470460 05/23/2006 23:00 29.2 5,870 6.0 7.7

08470460 05/23/2006 23:15 28.9 5,320 5.9 7.8

08470460 05/23/2006 23:30 29.0 5,950 5.8 7.8

08470460 05/23/2006 23:45 28.9 6,170 5.6 7.7

08470460 05/24/2006 00:00 28.9 5,770 5.6 7.7

08470460 05/24/2006 00:15 28.9 7,930 5.3 7.7

08470460 05/24/2006 00:30 28.9 6,760 5.4 7.7

08470460 05/24/2006 00:45 28.8 7,030 5.3 7.7

08470460 05/24/2006 01:00 28.8 9,080 4.8 7.7

08470460 05/24/2006 01:15 28.6 6,270 5.3 7.7

08470460 05/24/2006 01:30 28.6 6,180 5.3 7.7

08470460 05/24/2006 01:45 28.6 6,180 5.5 7.7

08470460 05/24/2006 02:00 28.5 5,940 5.5 7.7

08470460 05/24/2006 02:15 28.5 6,290 5.4 7.7

08470460 05/24/2006 02:30 28.5 6,180 5.4 7.7

08470460 05/24/2006 02:45 28.4 5,890 5.4 7.7

08470460 05/24/2006 03:00 28.4 5,990 5.3 7.7

08470460 05/24/2006 03:15 28.4 5,970 5.4 7.7

08470460 05/24/2006 03:30 28.4 5,680 5.4 7.7

08470460 05/24/2006 03:45 28.3 5,580 5.3 7.7

08470460 05/24/2006 04:00 28.2 5,480 5.3 7.7

08470460 05/24/2006 04:15 28.2 5,410 5.3 7.7

08470460 05/24/2006 04:30 28.2 5,380 5.3 7.7

08470460 05/24/2006 04:45 28.4 5,610 5.2 7.7

08470460 05/24/2006 05:00 28.2 5,390 5.2 7.7

08470460 05/24/2006 05:15 28.2 5,320 5.2 7.7

08470460 05/24/2006 05:30 28.3 5,350 5.1 7.7

08470460 05/24/2006 05:45 28.2 5,320 5.2 7.7

08470460 05/24/2006 06:00 28.2 5,270 5.1 7.7

08470460 05/24/2006 06:15 28.2 5,280 5.0 7.7

08470460 05/24/2006 06:30 28.0 5,160 5.0 7.7

08470460 05/24/2006 06:45 28.1 5,120 5.0 7.7

08470460 05/24/2006 07:00 28.0 5,170 5.0 7.7

08470460 05/24/2006 07:15 28.0 4,330 4.9 7.7

08470460 05/24/2006 07:30 28.0 5,120 4.8 7.7

08470460 05/24/2006 07:45 28.0 5,430 4.7 7.7

08470460 05/24/2006 08:00 28.2 14,800 2.5 7.5

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)

Station 08470460 May data-collection period—Continued

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)
28 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–2.2. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470460 May data-collection period—Continued

08470460 05/24/2006 08:15 28.0 7,960 4.1 7.6

08470460 05/24/2006 08:30 28.1 7,220 4.1 7.6

08470460 05/24/2006 08:45 27.9 5,850 4.5 7.7

08470460 05/24/2006 09:00 27.9 6,040 4.3 7.6

08470460 05/24/2006 09:15 28.0 6,450 4.2 7.6

08470460 05/24/2006 09:30 28.0 5,920 4.4 7.6

08470460 05/24/2006 09:45 28.0 5,860 4.3 7.6

08470460 05/24/2006 10:00 28.0 5,880 4.5 7.7

08470460 05/24/2006 10:15 28.0 5,950 4.3 7.6

08470460 05/24/2006 10:30 28.1 6,540 4.4 7.6

08470460 05/24/2006 10:45 28.2 6,380 4.8 7.7

08470460 05/24/2006 11:00 28.2 6,260 4.8 7.7

08470460 05/24/2006 11:15 28.2 6,280 4.9 7.7

08470460 05/24/2006 11:30 28.3 6,280 4.9 7.7

08470460 05/24/2006 11:45 28.3 6,700 4.7 7.7

08470460 05/24/2006 12:00 28.3 6,990 4.7 7.7

08470460 05/24/2006 12:15 28.4 6,680 5.2 7.7

08470460 05/24/2006 12:30 28.4 6,820 4.9 7.7

08470460 05/24/2006 12:45 28.4 6,750 5.2 7.7

08470460 05/24/2006 13:00 28.5 6,580 5.5 7.7

Station 08470500 February data-collection period

08470500 02/22/2006 11:10 17.5 8,500 7.8 7.7

08470500 02/22/2006 11:25 17.6 7,870 7.6 7.8

08470500 02/22/2006 11:40 17.6 10,200 7.3 7.8

08470500 02/22/2006 11:55 17.7 10,200 7.2 7.8

08470500 02/22/2006 12:10 17.8 11,900 7.0 7.8

08470500 02/22/2006 12:25 17.9 12,900 7.0 7.8

08470500 02/22/2006 12:40 18.1 12,700 7.0 7.8

08470500 02/22/2006 12:55 18.2 10,800 7.0 7.8

08470500 02/22/2006 13:10 18.2 10,600 7.0 7.8

08470500 02/22/2006 13:25 18.5 12,000 7.0 7.8

08470500 02/22/2006 13:40 18.5 13,800 6.8 7.8

08470500 02/22/2006 13:55 18.6 13,800 6.9 7.8

08470500 02/22/2006 14:10 18.6 14,800 6.6 7.8

08470500 02/22/2006 14:25 18.8 13,900 6.7 7.9

08470500 02/22/2006 14:40 18.8 14,000 6.5 7.8

08470500 02/22/2006 14:55 18.9 15,500 6.6 7.9

08470500 02/22/2006 15:10 19.1 15,100 6.6 7.9

08470500 02/22/2006 15:25 19.1 16,200 6.4 7.9

08470500 02/22/2006 15:40 19.2 15,400 6.6 7.9

08470500 02/22/2006 15:55 19.1 15,400 6.5 7.9

08470500 02/22/2006 16:10 19.3 16,300 6.5 7.9

08470500 02/22/2006 16:25 19.2 17,000 6.3 7.8

08470500 02/22/2006 16:40 19.4 15,200 6.6 7.9

08470500 02/22/2006 16:55 19.5 14,100 6.5 7.9

08470500 02/22/2006 17:10 19.5 15,000 6.5 7.9

08470500 02/22/2006 17:25 19.5 16,200 6.4 7.8

08470500 02/22/2006 17:40 19.5 16,600 6.3 7.8

08470500 02/22/2006 17:55 19.5 16,400 6.3 7.8

08470500 02/22/2006 18:10 19.5 17,800 6.2 7.8

08470500 02/22/2006 18:25 19.5 17,700 6.0 7.8

08470500 02/22/2006 18:40 19.6 18,000 6.0 7.8

08470500 02/22/2006 18:55 19.5 18,100 6.0 7.8

08470500 02/22/2006 19:10 19.5 18,100 6.0 7.8

08470500 02/22/2006 19:25 19.5 18,300 5.9 7.8

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)

Station 08470500 February data-collection period—Continued

08470500 02/22/2006 19:40 19.4 18,800 5.7 7.8

08470500 02/22/2006 19:55 19.6 19,000 5.7 7.8

08470500 02/22/2006 20:10 19.4 19,000 5.6 7.8

08470500 02/22/2006 20:25 19.5 19,200 5.7 7.8

08470500 02/22/2006 20:40 19.4 18,900 5.6 7.8

08470500 02/22/2006 20:55 19.4 19,200 5.7 7.8

08470500 02/22/2006 21:10 19.4 19,200 5.5 7.8

08470500 02/22/2006 21:25 19.4 18,900 5.5 7.8

08470500 02/22/2006 21:40 19.6 19,000 5.9 7.8

08470500 02/22/2006 21:55 19.6 19,300 5.8 7.8

08470500 02/22/2006 22:10 19.3 19,200 5.3 7.8

08470500 02/22/2006 22:25 19.4 18,800 5.4 7.8

08470500 02/22/2006 22:40 19.6 18,900 6.0 7.8

08470500 02/22/2006 22:55 19.5 19,000 5.7 7.8

08470500 02/22/2006 23:10 19.6 18,500 6.0 7.8

08470500 02/22/2006 23:25 19.5 18,200 5.8 7.8

08470500 02/22/2006 23:40 19.6 18,300 5.8 7.8

08470500 02/22/2006 23:55 19.5 18,300 5.8 7.8

08470500 02/23/2006 00:10 19.5 18,000 6.0 7.8

08470500 02/23/2006 00:25 19.5 17,700 6.0 7.8

08470500 02/23/2006 00:40 19.5 17,300 5.9 7.8

08470500 02/23/2006 00:55 19.6 17,200 6.0 7.8

08470500 02/23/2006 01:10 19.6 16,800 6.1 7.8

08470500 02/23/2006 01:25 19.6 16,600 6.1 7.8

08470500 02/23/2006 01:40 19.6 16,600 6.1 7.8

08470500 02/23/2006 01:55 19.6 16,500 6.1 7.8

08470500 02/23/2006 02:10 19.6 16,300 6.1 7.8

08470500 02/23/2006 02:25 19.6 16,000 6.2 7.8

08470500 02/23/2006 02:40 19.6 16,100 6.0 7.8

08470500 02/23/2006 02:55 19.6 15,800 6.0 7.8

08470500 02/23/2006 03:10 19.6 15,800 6.1 7.8

08470500 02/23/2006 03:25 19.6 15,700 6.3 7.8

08470500 02/23/2006 03:40 19.6 15,600 6.2 7.8

08470500 02/23/2006 03:55 19.5 15,600 6.3 7.8

08470500 02/23/2006 04:10 19.5 15,400 6.3 7.8

08470500 02/23/2006 04:25 19.6 15,300 6.3 7.8

08470500 02/23/2006 04:40 19.6 15,200 6.3 7.8

08470500 02/23/2006 04:55 19.5 14,400 6.2 7.8

08470500 02/23/2006 05:10 19.5 14,400 6.1 7.8

08470500 02/23/2006 05:25 19.5 13,700 5.9 7.8

08470500 02/23/2006 05:40 19.5 13,600 6.0 7.8

08470500 02/23/2006 05:55 19.5 12,700 6.0 7.8

08470500 02/23/2006 06:10 19.5 12,600 6.0 7.8

08470500 02/23/2006 06:25 19.5 11,300 6.0 7.8

08470500 02/23/2006 06:40 19.5 12,300 6.0 7.8

08470500 02/23/2006 06:55 19.5 11,700 6.0 7.8

08470500 02/23/2006 07:10 19.5 12,300 6.0 7.8

08470500 02/23/2006 07:25 19.4 12,500 5.9 7.8

08470500 02/23/2006 07:40 19.6 9,620 6.0 7.8

08470500 02/23/2006 07:55 19.6 10,500 6.0 7.8

08470500 02/23/2006 08:10 19.7 9,790 6.0 7.8

08470500 02/23/2006 08:25 19.7 9,150 6.1 7.8

08470500 02/23/2006 08:40 19.7 10,200 6.0 7.8

08470500 02/23/2006 08:55 19.7 9,790 6.1 7.8

08470500 02/23/2006 09:10 19.7 10,200 6.1 7.8

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)
Appendix 1 29

Appendix 1–2.2. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470500 February data-collection period—Continued

08470500 02/23/2006 09:25 19.8 9,340 6.2 7.8

08470500 02/23/2006 09:40 19.8 10,500 6.2 7.8

08470500 02/23/2006 09:55 19.8 8,750 6.4 7.8

08470500 02/23/2006 10:10 19.8 8,720 6.5 7.8

08470500 02/23/2006 10:25 19.9 8,650 6.6 7.8

08470500 02/23/2006 10:40 19.9 8,800 6.7 7.8

08470500 02/23/2006 10:55 19.8 9,320 6.6 7.8

08470500 02/23/2006 11:10 19.7 10,100 6.6 7.8

08470500 02/23/2006 11:25 19.7 10,800 6.7 7.8

08470500 02/23/2006 11:40 19.7 11,300 6.7 7.8

08470500 02/23/2006 11:55 19.7 12,300 6.7 7.8

08470500 02/23/2006 12:10 19.7 13,200 6.6 7.8

08470500 02/23/2006 12:25 19.7 13,900 6.8 7.9

08470500 02/23/2006 12:40 19.7 13,900 7.0 7.9

08470500 02/23/2006 12:55 19.7 14,100 6.8 7.9

08470500 02/23/2006 13:10 19.7 14,200 6.9 7.9

08470500 02/23/2006 13:25 19.7 14,400 7.0 7.9

08470500 02/23/2006 13:40 19.7 14,400 7.1 7.9

08470500 02/23/2006 13:55 19.7 14,400 7.1 7.9

08470500 02/23/2006 14:10 19.7 14,300 7.0 7.9

08470500 02/23/2006 14:25 19.7 14,500 7.0 7.9

Station 08470500 May data-collection period

08470500 05/23/2006 10:45 27.5 8,970 4.3 7.6

08470500 05/23/2006 11:00 27.3 8,550 4.7 7.7

08470500 05/23/2006 11:15 27.2 8,370 4.6 7.6

08470500 05/23/2006 11:30 27.3 8,320 4.3 7.6

08470500 05/23/2006 11:45 27.4 8,210 4.7 7.6

08470500 05/23/2006 12:00 27.5 8,060 4.9 7.7

08470500 05/23/2006 12:15 27.6 8,090 5.0 7.7

08470500 05/23/2006 12:30 27.6 8,000 5.0 7.7

08470500 05/23/2006 12:45 27.7 7,930 5.3 7.7

08470500 05/23/2006 13:00 27.9 7,950 5.5 7.7

08470500 05/23/2006 13:15 28.1 7,960 5.4 7.7

08470500 05/23/2006 13:30 28.2 8,060 5.4 7.7

08470500 05/23/2006 13:45 28.6 7,930 5.8 7.7

08470500 05/23/2006 14:00 28.7 7,900 5.9 7.7

08470500 05/23/2006 14:15 28.9 7,810 5.9 7.7

08470500 05/23/2006 14:30 29.1 7,680 6.4 7.8

08470500 05/23/2006 14:45 29.2 7,670 6.9 7.8

08470500 05/23/2006 15:00 29.3 7,530 6.9 7.8

08470500 05/23/2006 15:15 29.4 7,420 7.1 7.8

08470500 05/23/2006 15:30 29.6 7,400 6.8 7.8

08470500 05/23/2006 15:45 29.7 7,280 6.8 7.8

08470500 05/23/2006 16:00 29.9 7,120 7.0 7.8

08470500 05/23/2006 16:15 29.8 7,100 7.2 7.8

08470500 05/23/2006 16:30 29.8 6,880 7.8 7.9

08470500 05/23/2006 16:45 30.0 6,870 7.9 7.9

08470500 05/23/2006 17:00 30.3 6,650 8.3 7.9

08470500 05/23/2006 17:15 30.2 6,780 8.2 7.9

08470500 05/23/2006 17:30 30.4 6,700 8.2 7.9

08470500 05/23/2006 17:45 30.4 6,720 8.2 7.9

08470500 05/23/2006 18:00 30.5 6,650 8.4 7.9

08470500 05/23/2006 18:15 30.6 6,510 8.7 8.0

08470500 05/23/2006 18:30 30.6 6,550 8.6 8.0

08470500 05/23/2006 18:45 30.4 6,710 8.6 7.9

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)

Station 08470500 May data-collection period—Continued

08470500 05/23/2006 19:00 30.2 6,810 9.0 8.0

08470500 05/23/2006 19:15 30.3 6,830 9.4 8.0

08470500 05/23/2006 19:30 30.3 6,680 9.6 8.0

08470500 05/23/2006 19:45 30.2 6,730 9.4 8.0

08470500 05/23/2006 20:00 30.0 6,750 9.6 8.0

08470500 05/23/2006 20:15 29.9 6,880 9.4 8.0

08470500 05/23/2006 20:30 29.9 6,870 9.3 8.0

08470500 05/23/2006 20:45 29.8 6,880 9.2 8.0

08470500 05/23/2006 21:00 29.6 6,860 9.2 8.0

08470500 05/23/2006 21:15 29.6 6,860 9.0 8.0

08470500 05/23/2006 21:30 29.4 6,930 8.7 8.0

08470500 05/23/2006 21:45 29.4 6,880 8.7 8.0

08470500 05/23/2006 22:00 29.3 6,960 8.4 7.9

08470500 05/23/2006 22:15 29.2 7,040 8.3 7.9

08470500 05/23/2006 22:30 29.1 7,000 8.4 8.0

08470500 05/23/2006 22:45 29 6,990 8.2 7.9

08470500 05/23/2006 23:00 29 7,290 7.8 7.9

08470500 05/23/2006 23:15 28.8 7,050 7.7 7.9

08470500 05/23/2006 23:30 29 7,600 7.1 7.8

08470500 05/23/2006 23:45 28.8 7,370 7.4 7.9

08470500 05/24/2006 00:00 28.7 7,250 7.6 7.9

08470500 05/24/2006 00:15 28.7 7,360 7.3 7.9

08470500 05/24/2006 00:30 28.7 7,360 7.3 7.9

08470500 05/24/2006 00:45 28.7 7,540 6.6 7.8

08470500 05/24/2006 01:00 28.7 7,480 6.5 7.8

08470500 05/24/2006 01:15 28.5 7,450 6.6 7.8

08470500 05/24/2006 01:30 28.5 7,540 6.4 7.8

08470500 05/24/2006 01:45 28.3 7,450 6.6 7.8

08470500 05/24/2006 02:00 28.3 7,490 6.4 7.8

08470500 05/24/2006 02:15 28.3 7,380 6.2 7.8

08470500 05/24/2006 02:30 28.3 7,350 5.9 7.8

08470500 05/24/2006 02:45 28.3 7,260 5.8 7.8

08470500 05/24/2006 03:00 28.3 7,290 5.8 7.8

08470500 05/24/2006 03:15 28.3 7,280 5.7 7.8

08470500 05/24/2006 03:30 28.2 7,220 5.7 7.8

08470500 05/24/2006 03:45 28.2 7,280 5.6 7.8

08470500 05/24/2006 04:00 28.2 7,250 5.5 7.8

08470500 05/24/2006 04:15 28.2 7,250 5.2 7.7

08470500 05/24/2006 04:30 28.1 7,350 5.1 7.7

08470500 05/24/2006 04:45 28.1 7,330 5.1 7.7

08470500 05/24/2006 05:00 28.1 7,300 5.1 7.7

08470500 05/24/2006 05:15 28.1 7,470 4.8 7.7

08470500 05/24/2006 05:30 28.0 7,580 4.7 7.7

08470500 05/24/2006 05:45 28.0 7,590 4.6 7.7

08470500 05/24/2006 06:00 28.0 7,500 4.7 7.7

08470500 05/24/2006 06:15 27.9 7,440 4.5 7.7

08470500 05/24/2006 06:30 27.9 7,380 4.5 7.7

08470500 05/24/2006 06:45 27.9 7,370 4.3 7.7

08470500 05/24/2006 07:00 27.8 7,400 4.2 7.7

08470500 05/24/2006 07:15 27.8 7,390 4.2 7.7

08470500 05/24/2006 07:30 27.8 7,390 4.0 7.7

08470500 05/24/2006 07:45 27.8 7,390 4.0 7.7

08470500 05/24/2006 08:00 27.8 7,520 3.9 7.6

08470500 05/24/2006 08:15 27.7 7,400 4.0 7.7

08470500 05/24/2006 08:30 27.7 7,470 3.9 7.7

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)
30 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–2.2. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470500 May data-collection period—Continued

08470500 05/24/2006 08:45 27.7 12,000 2.4 7.5

08470500 05/24/2006 09:00 27.7 11,200 3.1 7.6

08470500 05/24/2006 09:15 27.7 10,900 2.9 7.6

08470500 05/24/2006 09:30 27.7 10,700 3.1 7.6

08470500 05/24/2006 09:45 27.7 10,800 3.2 7.6

08470500 05/24/2006 10:00 27.7 10,800 3.4 7.6

08470500 05/24/2006 10:15 27.8 10,500 3.8 7.7

08470500 05/24/2006 10:30 27.9 11,500 3.8 7.7

08470500 05/24/2006 10:45 28.0 10,700 4.6 7.7

08470500 05/24/2006 11:00 28.0 10,800 4.4 7.7

08470500 05/24/2006 11:15 28.1 10,700 5.6 7.8

08470500 05/24/2006 11:30 28.1 10,700 5.5 7.8

08470500 05/24/2006 11:45 28.3 10,300 6.2 7.8

08470500 05/24/2006 12:00 28.5 10,600 7.7 7.9

08470500 05/24/2006 12:15 28.7 10,500 9.0 8.0

08470500 05/24/2006 12:30 29.0 9,740 11.4 8.2

08470500 05/24/2006 12:45 29.1 9,950 12.9 8.3

08470500 05/24/2006 13:00 29.2 10,100 13 8.3

08470500 05/24/2006 13:15 29.3 10,000 13 8.3

Station 08470520 February data-collection period

08470520 02/22/2006 12:00 19.3 13,000 7.4 7.8

08470520 02/22/2006 12:15 19.3 12,900 7.4 7.8

08470520 02/22/2006 12:30 19.3 13,200 7.3 7.8

08470520 02/22/2006 12:45 19.3 13,100 7.3 7.8

08470520 02/22/2006 13:00 19.3 13,000 7.4 7.8

08470520 02/22/2006 13:15 19.4 12,900 7.5 7.8

08470520 02/22/2006 13:30 19.4 12,800 7.6 7.8

08470520 02/22/2006 13:45 19.5 12,700 7.7 7.8

08470520 02/22/2006 14:00 19.5 12,600 7.9 7.8

08470520 02/22/2006 14:15 19.4 12,700 7.8 7.8

08470520 02/22/2006 14:30 19.4 12,700 7.8 7.8

08470520 02/22/2006 14:45 19.4 13,100 7.7 7.8

08470520 02/22/2006 15:00 19.4 12,900 7.7 7.8

08470520 02/22/2006 15:15 19.4 12,700 7.8 7.8

08470520 02/22/2006 15:30 19.4 12,400 7.9 7.8

08470520 02/22/2006 15:45 19.4 12,300 8.0 7.8

08470520 02/22/2006 16:00 19.4 12,600 8.0 7.8

08470520 02/22/2006 16:15 19.4 12,400 8.1 7.8

08470520 02/22/2006 16:30 19.4 12,400 8.2 7.8

08470520 02/22/2006 16:45 19.4 12,700 8.2 7.8

08470520 02/22/2006 17:00 19.4 12,600 8.3 7.8

08470520 02/22/2006 17:15 19.4 12,600 8.3 7.8

08470520 02/22/2006 17:30 19.4 12,300 8.4 7.9

08470520 02/22/2006 17:45 19.4 12,600 8.4 7.8

08470520 02/22/2006 18:00 19.4 12,600 8.5 7.9

08470520 02/22/2006 18:15 19.4 12,500 8.7 7.9

08470520 02/22/2006 18:30 19.4 12,400 8.7 7.9

08470520 02/22/2006 18:45 19.4 12,500 8.8 7.9

08470520 02/22/2006 19:00 19.4 12,700 8.7 7.9

08470520 02/22/2006 19:15 19.3 13,000 7.4 7.8

08470520 02/22/2006 19:30 19.3 12,900 7.4 7.8

08470520 02/22/2006 19:45 19.3 13,200 7.3 7.8

08470520 02/22/2006 20:00 19.3 13,100 7.3 7.8

08470520 02/22/2006 20:15 19.3 13,000 7.4 7.8

08470520 02/22/2006 20:30 19.4 12,900 7.5 7.8

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)

Station 08470520 February data-collection period—Continued

08470520 02/22/2006 20:45 19.4 12,800 7.6 7.8

08470520 02/22/2006 21:00 19.5 12,700 7.7 7.8

08470520 02/22/2006 21:15 19.5 12,600 7.9 7.8

08470520 02/22/2006 21:30 19.4 12,700 7.8 7.8

08470520 02/22/2006 21:45 19.4 12,700 7.8 7.8

08470520 02/22/2006 22:00 19.4 13,100 7.7 7.8

08470520 02/22/2006 22:15 19.4 12,900 7.7 7.8

08470520 02/22/2006 22:30 19.4 12,700 7.8 7.8

08470520 02/22/2006 22:45 19.4 12,400 7.9 7.8

08470520 02/22/2006 23:00 19.4 12,300 8.0 7.8

08470520 02/22/2006 23:15 19.4 12,600 8.0 7.8

08470520 02/22/2006 23:30 19.4 12,400 8.1 7.8

08470520 02/22/2006 23:45 19.4 12,400 8.2 7.8

08470520 02/23/2006 00:00 19.4 12,700 8.2 7.8

08470520 02/23/2006 00:15 19.4 12,600 8.3 7.8

08470520 02/23/2006 00:30 19.4 12,600 8.3 7.8

08470520 02/23/2006 00:45 19.4 12,300 8.4 7.9

08470520 02/23/2006 01:00 19.4 12,600 8.4 7.8

08470520 02/23/2006 01:15 19.4 12,600 8.5 7.9

08470520 02/23/2006 01:30 19.4 12,500 8.7 7.9

08470520 02/23/2006 01:45 19.4 12,400 8.7 7.9

08470520 02/23/2006 02:00 19.4 12,500 8.8 7.9

08470520 02/23/2006 02:15 19.4 12,700 8.7 7.9

08470520 02/23/2006 02:30 19.3 13,000 7.4 7.8

08470520 02/23/2006 02:45 19.3 12,900 7.4 7.8

08470520 02/23/2006 03:00 19.3 13,200 7.3 7.8

08470520 02/23/2006 03:15 19.3 13,100 7.3 7.8

08470520 02/23/2006 03:30 19.3 13,000 7.4 7.8

08470520 02/23/2006 03:45 19.4 12,900 7.5 7.8

08470520 02/23/2006 04:00 19.4 12,800 7.6 7.8

08470520 02/23/2006 04:15 19.5 12,700 7.7 7.8

08470520 02/23/2006 04:30 19.5 12,600 7.9 7.8

08470520 02/23/2006 04:45 19.4 12,700 7.8 7.8

08470520 02/23/2006 05:00 19.4 12,700 7.8 7.8

08470520 02/23/2006 05:15 19.4 13,100 7.7 7.8

08470520 02/23/2006 05:30 19.4 12,900 7.7 7.8

08470520 02/23/2006 05:45 19.4 12,700 7.8 7.8

08470520 02/23/2006 06:00 19.4 12,400 7.9 7.8

08470520 02/23/2006 06:15 19.4 12,300 8.0 7.8

08470520 02/23/2006 06:30 19.4 12,600 8.0 7.8

08470520 02/23/2006 06:45 19.4 12,400 8.1 7.8

08470520 02/23/2006 07:00 19.4 12,400 8.2 7.8

08470520 02/23/2006 07:15 19.4 12,700 8.2 7.8

08470520 02/23/2006 07:30 19.4 12,600 8.3 7.8

08470520 02/23/2006 07:45 19.4 12,600 8.3 7.8

08470520 02/23/2006 08:00 19.4 12,300 8.4 7.9

08470520 02/23/2006 08:15 19.4 12,600 8.4 7.8

08470520 02/23/2006 08:30 19.4 12,600 8.5 7.9

08470520 02/23/2006 08:45 19.4 12,500 8.7 7.9

08470520 02/23/2006 09:00 19.4 12,400 8.7 7.9

08470520 02/23/2006 09:15 19.4 12,500 8.8 7.9

08470520 02/23/2006 09:30 19.4 12,700 8.7 7.9

08470520 02/23/2006 09:45 19.3 13,000 7.4 7.8

08470520 02/23/2006 10:00 19.3 12,900 7.4 7.8

08470520 02/23/2006 10:15 19.3 13,200 7.3 7.8

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)
Appendix 1 31

Appendix 1–2.2. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

Station 08470520 February data-collection period—Continued

08470520 02/23/2006 10:30 19.3 13,100 7.3 7.8

08470520 02/23/2006 10:45 19.3 13,000 7.4 7.8

08470520 02/23/2006 11:00 19.4 12,900 7.5 7.8

08470520 02/23/2006 11:15 19.4 12,800 7.6 7.8

08470520 02/23/2006 11:30 19.5 12,700 7.7 7.8

08470520 02/23/2006 11:45 19.5 12,600 7.9 7.8

08470520 02/23/2006 12:00 19.4 12,700 7.8 7.8

08470520 02/23/2006 12:15 19.4 12,700 7.8 7.8

08470520 02/23/2006 12:30 19.4 13,100 7.7 7.8

08470520 02/23/2006 12:45 19.4 12,900 7.7 7.8

08470520 02/23/2006 13:00 19.4 12,700 7.8 7.8

08470520 02/23/2006 13:15 19.4 12,400 7.9 7.8

08470520 02/23/2006 13:30 19.4 12,300 8.0 7.8

08470520 02/23/2006 13:45 19.4 12,600 8.0 7.8

08470520 02/23/2006 14:00 19.4 12,400 8.1 7.8

08470520 02/23/2006 14:15 19.4 12,400 8.2 7.8

08470520 02/23/2006 14:30 19.4 12,700 8.2 7.8

08470520 02/23/2006 14:45 19.4 12,600 8.3 7.8

Station 08470520 May data-collection period

08470520 05/23/2006 10:15 27.2 7,220 7.9 7.9

08470520 05/23/2006 10:30 27.3 7,560 9.3 8.0

08470520 05/23/2006 10:45 27.5 7,980 8.8 8.0

08470520 05/23/2006 11:00 27.8 8,320 8.3 7.9

08470520 05/23/2006 11:15 28.0 8,590 8.6 8.0

08470520 05/23/2006 11:30 28.1 8,580 10.4 8.1

08470520 05/23/2006 11:45 28.1 8,610 10.7 8.1

08470520 05/23/2006 12:00 28.2 8,750 11.6 8.2

08470520 05/23/2006 12:15 28.3 8,630 13.8 8.4

08470520 05/23/2006 12:30 28.4 8,720 13.8 8.3

08470520 05/23/2006 12:45 28.4 8,760 13.7 8.3

08470520 05/23/2006 13:00 28.5 8,690 14.6 8.4

08470520 05/23/2006 13:15 28.5 8,620 14.9 8.4

08470520 05/23/2006 13:30 28.6 8,570 15.5 8.4

08470520 05/23/2006 13:45 28.7 8,520 16.1 8.5

08470520 05/23/2006 14:00 28.8 8,480 17.1 8.5

08470520 05/23/2006 14:15 29.1 8,460 18.3 8.6

08470520 05/23/2006 14:30 29.4 8,400 18.9 8.6

08470520 05/23/2006 14:45 29.5 8,400 19.6 8.7

08470520 05/23/2006 15:00 29.5 8,460 19.5 8.7

08470520 05/23/2006 15:15 30.1 8,360 19.3 8.7

08470520 05/23/2006 15:30 29.8 8,470 19.1 8.6

08470520 05/23/2006 15:45 29.4 8,510 13.7 8.3

08470520 05/23/2006 16:00 29.5 8,530 15.7 8.4

08470520 05/23/2006 16:15 29.9 8,580 15.5 8.5

08470520 05/23/2006 16:30 30.0 8,560 16.3 8.5

08470520 05/23/2006 16:45 30.2 8,590 17.1 8.5

08470520 05/23/2006 17:00 30.4 8,600 19.5 8.6

08470520 05/23/2006 17:15 30.5 8,720 18.5 8.6

08470520 05/23/2006 17:30 30.8 8,640 21.6 8.7

08470520 05/23/2006 17:45 30.6 8,660 19.8 8.6

08470520 05/23/2006 18:00 31.0 8,220 18.8 8.6

08470520 05/23/2006 18:15 31.1 8,190 20.5 8.7

08470520 05/23/2006 18:30 31.5 7,970 20.2 8.6

08470520 05/23/2006 18:45 31.0 8,440 21.3 8.7

08470520 05/23/2006 19:00 31.6 8,180 21.7 8.7

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)

Station 08470520 May data-collection period—Continued

08470520 05/23/2006 19:15 31.2 7,990 19.1 8.6

08470520 05/23/2006 19:30 31.3 8,360 21.7 8.7

08470520 05/23/2006 19:45 31.1 8,420 20.7 8.7

08470520 05/23/2006 20:00 31.0 8,270 19.9 8.6

08470520 05/23/2006 20:15 31.3 8,200 21.6 8.7

08470520 05/23/2006 20:30 31.0 8,350 19.9 8.6

08470520 05/23/2006 20:45 30.4 8,460 17.8 8.5

08470520 05/23/2006 21:00 30.5 8,180 18.5 8.5

08470520 05/23/2006 21:15 30.4 8,260 17.7 8.5

08470520 05/23/2006 21:30 30.0 8,120 14.8 8.4

08470520 05/23/2006 21:45 30.1 8,200 14.9 8.4

08470520 05/23/2006 22:00 29.8 8,240 13.8 8.3

08470520 05/23/2006 22:15 29.7 8,460 13.8 8.3

08470520 05/23/2006 22:30 29.6 8,340 13.0 8.3

08470520 05/23/2006 22:45 29.6 8,400 12.9 8.3

08470520 05/23/2006 23:00 29.5 8,500 12.5 8.2

08470520 05/23/2006 23:15 29.4 8,500 12.1 8.2

08470520 05/23/2006 23:30 29.4 8,540 11.8 8.2

08470520 05/23/2006 23:45 29.4 8,520 12.0 8.2

08470520 05/24/2006 00:00 29.5 8,560 12.3 8.2

08470520 05/24/2006 00:15 29.3 8,480 11.8 8.2

08470520 05/24/2006 00:30 29.3 8,520 11.6 8.2

08470520 05/24/2006 00:45 29.3 8,500 11.3 8.2

08470520 05/24/2006 01:00 29.2 8,470 11.3 8.2

08470520 05/24/2006 01:15 29.2 8,410 11.0 8.2

08470520 05/24/2006 01:30 29.2 8,460 11.0 8.2

08470520 05/24/2006 01:45 29.1 8,470 11.1 8.2

08470520 05/24/2006 02:00 29.1 8,440 11.2 8.2

08470520 05/24/2006 02:15 29.1 8,440 11.0 8.2

08470520 05/24/2006 02:30 29.1 8,470 10.9 8.2

08470520 05/24/2006 02:45 29.0 8,450 10.9 8.2

08470520 05/24/2006 03:00 29.0 8,400 10.7 8.1

08470520 05/24/2006 03:15 29.0 8,430 10.7 8.1

08470520 05/24/2006 03:30 28.9 8,410 10.5 8.1

08470520 05/24/2006 03:45 28.8 8,350 10.3 8.1

08470520 05/24/2006 04:00 28.8 8,360 10.2 8.1

08470520 05/24/2006 04:15 28.9 8,420 10.2 8.1

08470520 05/24/2006 04:30 28.8 8,430 10.2 8.1

08470520 05/24/2006 04:45 28.8 8,370 10.2 8.1

08470520 05/24/2006 05:00 28.7 8,380 10.2 8.1

08470520 05/24/2006 05:15 28.7 8,410 10.1 8.1

08470520 05/24/2006 05:30 28.6 8,400 9.9 8.1

08470520 05/24/2006 05:45 28.6 8,340 9.8 8.1

08470520 05/24/2006 06:00 28.5 8,320 9.6 8.1

08470520 05/24/2006 06:15 28.4 8,200 9.5 8.1

08470520 05/24/2006 06:30 28.4 8,240 9.3 8.0

08470520 05/24/2006 06:45 28.4 8,230 9.0 8.0

08470520 05/24/2006 07:00 28.3 8,150 8.7 8.0

08470520 05/24/2006 07:15 28.2 8,080 8.4 8.0

08470520 05/24/2006 07:30 28.0 7,960 8.0 8.0

08470520 05/24/2006 07:45 28.0 8,020 8.0 8.0

08470520 05/24/2006 08:00 28.0 8,110 8.1 7.9

08470520 05/24/2006 08:15 28.3 8,320 7.9 7.9

08470520 05/24/2006 08:30 28.1 8,170 7.8 7.9

08470520 05/24/2006 08:45 28.1 8,250 7.7 7.9

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)
32 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–2.2. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using multiparameter continuous 

water-quality monitors—Continued.

08470520 05/24/2006 09:00 28.1 8,220 8.0 7.9

08470520 05/24/2006 09:15 28.3 8,770 7.9 7.9

08470520 05/24/2006 09:30 28.2 10,800 6.6 7.8

08470520 05/24/2006 09:45 27.8 11,300 6.4 7.8

08470520 05/24/2006 10:00 27.8 10,900 6.6 7.8

08470520 05/24/2006 10:15 27.8 10,400 6.4 7.8

08470520 05/24/2006 10:30 28.0 10,600 6.7 7.8

08470520 05/24/2006 10:45 28.1 10,800 7.0 7.8

08470520 05/24/2006 11:00 28.2 11,500 7.2 7.9

08470520 05/24/2006 11:15 28.3 11,700 7.7 7.9

08470520 05/24/2006 11:30 28.4 11,400 7.3 7.9

08470520 05/24/2006 11:45 28.4 11,400 7.6 7.9

08470520 05/24/2006 12:00 28.7 10,900 9.5 8.0

08470520 05/24/2006 12:15 28.7 10,900 10.9 8.1

08470520 05/24/2006 12:30 28.8 10,900 10.4 8.1

08470520 05/24/2006 12:45 28.8 10,800 13.1 8.2

08470520 05/24/2006 13:00 29.0 10,700 14.2 8.3

08470520 05/24/2006 13:15 29.1 11,200 11.7 8.2

08470520 05/24/2006 13:30 29.1 11,000 14.6 8.3

Appendix 1–2.3.a. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using algal growth and mortality 

analyses/bioassay analysis. 

[+N, nitrogen addition; +NP, nitrogen and phosphorus addition; +P, phosphorus addition; control, no addition. R2, statistical measure of the degree to which two 

different things are related. An R2

 of 1.00 indicates perfect correlation; an R2 of 0 indicates no correlation. A negative growth rate indicates that phytoplankton are 

being consumed by zooplankton and is an algal mortality rate] 

USGS

station no.

Date and

time Sample type Average R2 Averagegrowth rate

08470450 02/22/2006 17:30 +N 0.95 0.556

08470450 02/23/2006 17:30 +NP .96 .430

08470450 02/24/2006 17:30 +P .98 .422

08470450 02/25/2006 17:30 control .96 .556

08470450 05/23/2006 11:30 +N .74 -.285

08470450 05/24/2006 11:30 +NP .18 .166

08470450 05/25/2006 11:30 +P .89 -.470

08470450 05/26/2006 11:30 control .78 -.398

08470460 02/22/2006 16:30 +N .90 .315

08470460 02/23/2006 16:30 +NP .91 .415

08470460 02/24/2006 16:30 +P .90 .315

08470460 02/25/2006 16:30 control .92 .553

08470460 05/23/2006 12:30 +N .77 .519

08470460 05/24/2006 12:30 +NP .32 .195

08470460 05/25/2006 12:30 +P .39 .220

08470460 05/26/2006 12:30 control .76 .493

USGS

station no.

Date and

time Sample type Average R2 Averagegrowth rate

08470520 02/25/2006 13:30 control 0.86 0.511

08470500 02/22/2006 15:30 +N .86 .512

08470500 02/23/2006 15:30 +NP .82 .398

08470500 02/24/2006 15:30 +P .82 .353

08470500 02/25/2006 15:30 control .65 .325

08470500 05/23/2006 13:30 +N .92 -.255

08470500 05/24/2006 13:30 +NP .54 -.193

08470500 05/25/2006 13:30 +P .78 -.235

08470500 05/26/2006 13:30 control .86 -.209

08470520 02/22/2006 13:30 +N .86 .498

08470520 02/23/2006 13:30 +NP .87 .440

08470520 02/24/2006 13:30 +P .85 .455

08470520 05/23/2006 14:30 +N .94 -.290

08470520 05/24/2006 14:30 +NP .57 -.189

08470520 05/25/2006 14:30 +P .95 -.332

08470520 05/26/2006 14:30 control .93 -.377

Station 08470520 May data-collection period—Continued

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)

Station 08470520 May data-collection period—Continued

USGS

station no.

Date

and time

Temperature

(°C)

Specific 

conductance

(μS/cm)

Dissolved

 oxygen

(mg/L)

pH

(standard

 units)
Appendix 1 33

Appendix 1–2.3.b. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using algal growth and mortality 

analyses/phytoplankton analysis.

[Division, type of phytoplankton; Taxa, a classification or group of organisms (for example, kingdom, phylum, class, order, family, genus, species—becomes 

more specific with increasing number; cells/mL, cells per milliliter of sample; sp, unknown species; --, not applicable; <, less than; mm, millimeter; >, more than]

USGS

station no.

Date and

time Division Taxa1 Taxa2 Count(cells/mL)

Sample

total

(cells/mL)

Station 08470450 February data-collection period 3,969

08470450 02/22/2006 17:30 Bacillariophyceae Surirella sp 142

08470450 02/22/2006 17:30 Bacillariophyceae Pennate -- 142

08470450 02/22/2006 17:30 Bacteria spirillum -- 142

08470450 02/22/2006 17:30 Chlorophyta Closterium sp 142

08470450 02/22/2006 17:30 Chlorophyta Crucigenia sp 2,267

08470450 02/22/2006 17:30 Chlorophyta Monoraphidium sp 283

08470450 02/22/2006 17:30 Cyanobacteria coccoid <5 mm 709

08470450 02/22/2006 17:30 Indeterminate coccoid >5 mm 142

Station 08470450 May data-collection period 23,241

08470450 05/23/2006 11:30 Bacillariophyceae centric small 992

08470450 05/23/2006 11:30 Bacillariophyceae centric large 142

08470450 05/23/2006 11:30 Bacillariophyceae pennate small 1,417

08470450 05/23/2006 11:30 Bacillariophyceae Placoneis sp 142

08470450 05/23/2006 11:30 Chlorophyta coccoid <5 mm 567

08470450 05/23/2006 11:30 Chlorophyta coccoid >5 mm 142

08470450 05/23/2006 11:30 Chlorophyta ovoid -- 142

08470450 05/23/2006 11:30 Chlorophyta Euglena sp 283

08470450 05/23/2006 11:30 Chlorophyta Kirchneriella sp 142

08470450 05/23/2006 11:30 Chlorophyta Monoraphidium sp 425

08470450 05/23/2006 11:30 Chlorophyta Oocystis sp 567

08470450 05/23/2006 11:30 Chlorophyta Scenedesmus quadricauda 1,700

08470450 05/23/2006 11:30 Chlorophyta Scenedesmus sp 8,502

08470450 05/23/2006 11:30 Chlorophyta Tetraedron sp 142

08470450 05/23/2006 11:30 Chlorophyta Trachelomonas sp 142

08470450 05/23/2006 11:30 Cyanobacteria coccoid <5 mm 709

08470450 05/23/2006 11:30 Cyanobacteria colony -- 2,267

08470450 05/23/2006 11:30 Cyanobacteria spirillum -- 425

08470450 05/23/2006 11:30 Cyanobacteria lunate -- 1,417

08470450 05/23/2006 11:30 Cyanobacteria Gloeocapsa punctata 283

08470450 05/23/2006 11:30 Indeterminate coccoid small 142

08470450 05/23/2006 11:30 Indeterminate coccoid large 2,409

08470450 05/23/2006 11:30 Indeterminate ovate -- 142

Station 08470460 February data-collection period 1,134

08470460 02/22/2006 16:30 Cyanobacteria coccoid <5 mm 1,134

Station 08470460 May data-collection period 13,604

08470460 05/23/2006 12:30 Bacillariophyceae pennate -- 142

08470460 05/23/2006 12:30 Bacteria spirillum -- 709

08470460 05/23/2006 12:30 Chlorophyta Ankistrodesmus sp 142

08470460 05/23/2006 12:30 Chlorophyta Kirchneriella sp 283

08470460 05/23/2006 12:30 Chlorophyta Monoraphidium sp 142

08470460 05/23/2006 12:30 Chlorophyta Scenedesmus acuminatus 1,134

08470460 05/23/2006 12:30 Chlorophyta Scenedesmus sp 3,401

08470460 05/23/2006 12:30 Chlorophyta coccoid <5 mm 283

08470460 05/23/2006 12:30 Cryptophyceae cryptomonad -- 142

08470460 05/23/2006 12:30 Cyanobacteria coccoid <5 mm 3,826

08470460 05/23/2006 12:30 Cyanobacteria coccoid >5 mm 142

08470460 05/23/2006 12:30 Cyanobacteria spirillum -- 1,134

08470460 05/23/2006 12:30 Cyanobacteria short rod -- 283

08470460 05/23/2006 12:30 Cyanobacteria lunate -- 1,275

08470460 05/23/2006 12:30 Cyanobacteria filament filament 283

08470460 05/23/2006 12:30 Indeterminate coccoid >5 mm 283
34 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Station 08470500 February data-collection period 2,056

08470500 02/22/2006 15:30 Chlorophyta Kirchneriella sp 142

08470500 02/22/2006 15:30 Cyanobacteria coccoid <5 mm 567

08470500 02/22/2006 15:30 Cyanobacteria filament 1 mm dia 709

08470500 02/22/2006 15:30 Cyanobacteria lunate -- 71

08470500 02/22/2006 15:30 Cyanobacteria Oscillatoria sp 567

Station 08470500 May data-collection period 171,180

08470500 05/23/2006 13:30 Bacillariophyceae centric small 3,684

08470500 05/23/2006 13:30 Bacillariophyceae centric large 283

08470500 05/23/2006 13:30 Bacillariophyceae Nitzschia sp 283

08470500 05/23/2006 13:30 Bacteria filament -- 4,251

08470500 05/23/2006 13:30 Bacteria spirillum -- 1,700

08470500 05/23/2006 13:30 Chlorophyta ovate small 2,834

08470500 05/23/2006 13:30 Chlorophyta ovate large 1,134

08470500 05/23/2006 13:30 Chlorophyta ovoid -- 283

08470500 05/23/2006 13:30 Chlorophyta paired cells -- 2,267

08470500 05/23/2006 13:30 Chlorophyta Ankistrodesmus sp 1,134

08470500 05/23/2006 13:30 Chlorophyta Kirchneriella sp 850

08470500 05/23/2006 13:30 Chlorophyta Scenedesmus sp 1,134

08470500 05/23/2006 13:30 Cryptophyceae cryptomonad -- 567

08470500 05/23/2006 13:30 Cyanobacteria coccoid <5 mm 4,251

08470500 05/23/2006 13:30 Cyanobacteria short rod -- 1,417

08470500 05/23/2006 13:30 Cyanobacteria spirillum -- 1,134

08470500 05/23/2006 13:30 Cyanobacteria lunate -- 283

08470500 05/23/2006 13:30 Cyanobacteria filament -- 1,417

08470500 05/23/2006 13:30 Cyanobacteria Merismopedia sp 99,762

08470500 05/23/2006 13:30 Indeterminate coccoid small 40,812

08470500 05/23/2006 13:30 Indeterminate ovate large 283

08470500 05/23/2006 13:30 Pyrrophyta dinoflagellate -- 1,417

Station 08470520 February data-collection period 1,843

08470520 02/22/2006 13:30 Bacillariophyceae pennate -- 71

08470520 02/22/2006 13:30 Chlorophyta Kirchneriella sp 425

08470520 02/22/2006 13:30 Chlorophyta Monoraphidium sp 142

08470520 02/22/2006 13:30 Cyanobacteria coccoid <5 mm 638

08470520 02/22/2006 13:30 Cyanobacteria short rod -- 142

08470520 02/22/2006 13:30 Indeterminate coccoid >5 mm 354

08470520 02/22/2006 13:30 Indeterminate ovate -- 71

Station 08470520 May data-collection period 264,143

08470520 05/23/2006 14:30 Bacillariophyceae pennate small 567

08470520 05/23/2006 14:30 Bacillariophyceae centric small 3,401

08470520 05/23/2006 14:30 Bacillariophyceae centric large 567

08470520 05/23/2006 14:30 Cyanobacteria coccoid <5 mm 1,700

08470520 05/23/2006 14:30 Cyanobacteria lunate -- 567

08470520 05/23/2006 14:30 Indeterminate ovate <5 mm 1,134

08470520 05/23/2006 14:30 Indeterminate ovate >5 mm 567

08470520 05/23/2006 14:30 Pyrrophyta dinoflagellate -- 255,640

Appendix 1–2.3.b. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using algal growth and mortality 

analyses/phytoplankton analysis—Continued.

USGS

station no.

Date and

time Division Taxa1 Taxa2 Count(cells/mL)

Sample

total

(cells/mL)
Appendix 1 35

Appendix 1–2.3.c. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using algal growth and mortality 

analyses/zooplankton analysis.

[ind./m3, number of individuals per cubic meter; total organisms, micro plus macrozooplankton] 

USGS

station no.

Date and

time

Macrozooplankton

 (ind./m3

)

Total

organisms

 (ind./m3

)

08470450 02/22/2006 17:30 122,000 734,000

08470460 02/22/2006 16:30 4,070 7,830

08470500 02/22/2006 15:30 1,610 2,030

08470520 02/22/2006 13:30 464 618

08470450 05/24/2006 11:30 279,000 929,000

08470460 05/24/2006 12:30 0 45,700,000

08470500 05/24/2006 13:30 0 15,800,000

08470520 05/24/2006 14:30 446,000 1,110,000
36 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–2.4.a. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using environmental discretesample analysis, February 2006.

[ft, feet; FNMU, formazin nephelometric units; mmHg, millimeters of mercury; mg/L, milligrams per liter; --, not sampled; PSU, practical salinity units; μS/cm, 

microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; E, estimated; CaCO3, calcium carbonate; N, nitrogen; NH4, ammonia; NO3, nitrate; P, 

phosphorus; <, less than; μg/L, micrograms per liter] 

Constituent

08470450 08470460 08470500 08470520

02/22/2006

 17:30

02/23/2006

 11:30

02/22/2006

 16:30

02/23/2006

 10:30

02/22/2006

 15:30

02/23/2006

 09:30

02/22/2006

 13:30

02/23/2006

 08:30

Sampling depth (ft) 1 1 1 1 1 1 1 1

Turbidity (FNMU) 190 110 55 55 28 18 34 12

Barometric pressure (mmHg) 762 762 761 762 760 760 762 762

Carbon dioxide (mg/L) -- -- -- -- -- -- -- --

Dissolved oxygen (mg/L) 8.1 6.7 5.1 6.8 6.4 6.2 8.1 7.7

Dissolved oxygen (percent of 

saturation)

90 76 54 76 74 70 91 88

pH (standard units) 7.7 7.7 7.7 7.7 7.9 7.8 7.8 7.8

Salinity (PSU) 2 2 17 3 10 5 7 8

Specific conductance (μS/cm) 3,640 3,790 27,300 4,780 16,200 9,340 12,400 13,100

Temperature, air (°C) E23.0 E21.0 E23.0 E21.0 E23.0 E21.0 E23.0 E21.0

Temperature, water (°C) 19.5 21.0 18.6 20.8 19.1 19.8 19.0 19.4

Acid neutralizing capacity (mg/L as 

CaCO3)

212 -- 219 -- 209 -- 209 --

Bicarbonate (mg/L) 256 -- 263 -- 250 -- 250 --

Carbonate (mg/L) 1 -- 2 -- 2 -- 2 --

Hydroxide (mg/L) <1 -- <1 -- <1 -- <1 --

Chloride (mg/L) 650 650 3,900 1,100 3,500 2,000 2,200 3,000

Sulfate (mg/L) 630 640 980 680 890 850 860 840

Residue on evaporation dried at 180 

°C (mg/L)

2,200 2,400 13,000 2,900 6,600 5,300 5,000 7,100

Fixed nonfilterable residue (mg/L) 67 87 53 52 25 10 14 4

Total nonfilterable residue (mg/L) 91 110 68 66 32 16 20 11

Ignition loss from nonfilterable 

residue (mg/L)

24.0 23.0 15.0 14.0 7.2 6.4 6.0 7.2

Ammonia plus organic nitrogen 

(mg/L as N)

.87 .96 .68 .98 .83 .53 1.00 .56

Ammonia (mg/L as NH4) .32 .33 .40 .32 .42 .33 .40 .31

Ammonia (mg/L as N) .25 .26 .31 .25 .33 .26 .31 .24

Nitrite plus nitrate (mg/L as N) 5.3 4.8 4.3 4.4 4.0 4.6 4.0 3.4

Organic nitrogen (mg/L) .62 .70 .37 .73 .50 .27 .69 .32

Particulate nitrogen (mg/L) .43 .49 .37 .40 .24 .23 .61 .22

Total nitrogen (mg/L) 6.2 5.8 5.0 5.4 4.8 5.1 5.0 4.0

Total nitrogen (mg/L as NO3) 27.3 25.5 22.0 23.8 21.4 22.7 22.1 17.5

Orthophosphate (mg/L) .981 1.630 1.070 1.230 1.230 .981 2.330 .052

Orthophosphate (mg/L as P) .32 .53 .35 .40 .40 .32 .76 .02

Phosphate (mg/L) .47 .46 .39 .49 .38 .39 .39 .24

Phosphorus (mg/L) E.41 E.41 E.58 E.44 E.50 E.51 E.50 E.36

Carbon (inorganic plus organic) 

suspended sediment (mg/L)

4.7 5.3 4.1 4.3 1.9 1.5 4.8 1.3

Organic carbon, filtered (mg/L) 4.2 E4.8 4.3 E4.5 4.8 E3.3 4.7 E4.6

Organic carbon, unfiltered (mg/L) 4.0 3.9 4.3 4.2 4.6 4.2 4.5 3.9

Biochemical oxygen demand 

(mg/L)

3.2 <2.0 2.4 2.5 2.6 <2.0 2.2 <2.0

Chlorophyll a (μg/L) <5.0 E14.0 E15.0 -- E10.0 E9.0 E10.0 E9.0

Pheophytin a (μg/L) <5.0 <5.0 <5.0 -- <5.0 <5.0 <5.0 <5.0
Appendix 1 37

Appendix 1–2.4.b. Data collected at near-surface depth of the Arroyo Colorado near Rio Hondo, Texas, using environmental discretesample analysis, May 2006.

[ft, feet; FNMU, formazin nephelometric units; mmHg, millimeters of mercury; mg/L, milligrams per liter; --, not sampled; PSU, practical salinity units; μS/cm, 

microsiemens per centimeter at 25 degrees Celsius; °C, degrees Celsius; CaCO3, calcium carbonate; E, estimated; N, nitrogen; NH4, ammonia; NO3, nitrate; P, 

phosphorus; μg/L, micrograms per liter; <, less than]

Constituent

08470450 08470460 08470500 08470520

05/23/2006

 11:30

05/24/2006

 11:30

05/23/2006

 12:30

05/24/2006

 10:30

05/23/2006

 13:30

05/24/2006

 09:30

05/23/2006

 14:30

05/24/2006

 07:30

Sampling depth (ft) 1 1 1 1 1 1 1 1

Turbidity (FNMU) 92 100 50 28 16 15 11 17

Barometric pressure (mmHg) 760 760 760 762 761 762 760 760

Carbon dioxide (mg/L) 4.8 4.0 4.5 4.0 3.7 4.4 .6 --

Dissolved oxygen (mg/L) 6.2 5.0 6.8 3.9 8.9 4.0 16.8 6.7

Dissolved oxygen (percent of saturation) 80 66 90 64 120 53 229 88

pH (standard units) 7.9 8.0 8.0 8.0 8.0 7.9 8.8 8.0

Salinity (PSU) 2 2 3 3 4 6 5 4

Specific conductance (μS/cm) 4,310 4,350 5,240 6,190 6,880 10,300 8,380 7,920

Temperature, air (°C) 32.8 31.1 33.9 28.9 33.9 27.8 33.9 23.9

Temperature, water (°C) 28.1 28.3 28.8 28.3 29.4 27.8 30.3 27.8

Acid neutralizing capacity (mg/L as 

CaCO3)

210 220 210 210 190 190 180 --

Bicarbonate (mg/L) -- -- -- -- -- -- -- --

Carbonate (mg/L) -- -- -- -- -- -- -- --

Hydroxide (mg/L) -- -- -- -- -- -- -- --

Chloride (mg/L) 830 840 1,100 1,500 1,700 3,100 2,200 2,100

Sulfate (mg/L) 880 890 860 950 940 1,100 910 960

Residue on evaporation dried at 180°C 

(mg/L)

2,800 2,800 3,200 3,800 4,200 6,000 5,000 4,800

Fixed nonfilterable residue (mg/L) 52 67 33 34 5 8 3 --

Total nonfilterable residue (mg/L) E69 E89 E43 E44 E10 E15 E28 E12

Ignition loss from nonfilterable residue 

(mg/L)

E17.0 E22.0 E10.0 E10.0 E5.2 E7.2 E25.0 <4.0

Ammonia plus organic nitrogen (mg/L 

as N)

.73 .77 .61 .66 .62 .72 2.20 <.500

Ammonia (mg/L as NH4) .11 .14 .15 .24 .23 .37 .12 .12

Ammonia (mg/L as N) .089 .110 .120 .190 .180 .290 .092 .091

Nitrite plus nitrate (mg/L as N) 3.7 3.5 1.8 3.5 3.0 2.8 1.3 2.8

Organic nitrogen (mg/L) .64 .66 .49 .47 .44 .43 2.10 --

Particulate nitrogen (mg/L) -- -- -- -- -- -- -- --

Total nitrogen (mg/L) 4.4 4.3 2.4 4.2 3.6 3.5 3.5 3.3

Total nitrogen (mg/L as NO3) 19.6 18.9 10.7 18.4 16.0 15.6 15.5 --

Orthophosphate (mg/L) 1.930 1.410 1.690 1.720 1.690 1.530 1.230 1.230

Orthophosphate (mg/L as P) .63 .46 .55 .56 .55 .50 .40 .40

Phosphate (mg/L) -- -- -- -- -- -- -- --

Phosphorus (mg/L) .58 .54 .59 .59 .53 .47 .54 .40

Carbon (inorganic plus organic) 

suspended sediment (mg/L)

-- -- -- -- -- -- -- --

Organic carbon, filtered (mg/L) 4.4 4.5 4.6 7.0 4.9 5.0 5.2 4.4

Organic carbon, unfiltered (mg/L) 4.7 4.7 5.0 8.0 5.2 5.2 11.0 5.0

Biochemical oxygen demand (mg/L) 3.3 3.2 3.6 7.3 2.6 7.7 E8.6 2.5

Chlorophyll a (μg/L) <3.0 E34.0 E25.0 E29.0 E21.0 E83.0 E240 E43.0

Pheophytin a (μg/L) E110 E12.0 <3.0 <3.0 <3.0 <3.0 E24.0 <3.0
38 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Appendix 1–3. Data collected for quality assurance/quality control from the Arroyo Colorado near Rio Hondo, Texas.

[mg/L, milligrams per liter; CaCO3, calcium carbonate; --, not sampled; <, less than; °C, degrees Celsius; N, nitrogen; NH4, ammonia; NO3, nitrate; P, phosphorus; μg/L, micrograms per liter; E, estimated]

Constituent

08470520 08470450 08470450 08470520

02/22/2006

13:05

02/22/2006

13:32

02/23/2006

11:02

02/23/2006

11:05

05/23/2006

11:02

05/23/2006

11:05

05/24/2006

07:02

05/24/2006

07:05

Sample type Blank Replicate Replicate Blank Replicate Blank Blank Replicate

Acid neutralizing capacity (mg/L as CaCO3) -- -- -- -- -- -- <5 210

Chloride (mg/L) <3 2,400 630 <3 810 <3 4 2,000

Sulfate (mg/L) <5 820 620 <5 860 <5 <5 980

Residue on evaporation dried at 180 °C (mg/L) <10 5,400 2,400 <10 2,800 14 <10 4,900

Fixed nonfilterable residue (mg/L) -- 15 96 -- 47 -- -- 5

Total nonfilterable residue (mg/L) <4 22 120 <4 62 <4 <4 11

Ignition loss from nonfilterable residue (mg/L) <4.0 6.8 24.0 <4.0 15.0 <4.0 <4.0 5.6

Ammonia plus organic nitrogen (mg/L as N) <.50 .89 1.00 <.50 1.10 <.50 <.50 <.50

Ammonia (mg/L as NH4) -- .41 .36 -- .11 .06 .04 .10

Ammonia (mg/L as N) <.100 .320 .280 <.100 .085 .047 .031 .081

Nitrite plus nitrate (mg/L as N) <.002 4.200 5.200 <.002 2.600 .007 .007 2.500

Organic nitrogen (mg/L) -- .57 .72 -- 1.00 -- -- --

Particulate nitrogen (mg/L) .05 .27 .54 <.01 .56 .01 .04 .39

Total nitrogen (mg/L) <.5 5.1 6.2 <.5 3.7 <.5 <.5 2.9

Total nitrogen (mg/L as NO3) -- 22.5 27.4 -- 16.4 -- -- --

Orthophosphate (mg/L) -- .92 1.63 -- 1.81 -- -- 1.07

Orthophosphate (mg/L as P) <.002 .300 .530 <.002 .590 <.002 <.002 .350

Phosphate (mg/L) <.05 .44 .55 <.05 -- -- -- --

Phosphorus (mg/L) .002 .510 .420 .002 .530 .002 .002 .380

Carbon (inorganic plus organic) suspended sediment 

(mg/L)

.30 2.10 6.30 <.05 5.10 .10 .10 2.00

Organic carbon, filtered (mg/L) <1.0 4.6 4.2 <1.0 4.6 <1.0 <1.0 4.6

Organic carbon, unfiltered (mg/L) <1.0 4.5 4.0 <1.0 4.7 <1.0 <1.0 4.8

Chlorophyll a (μg/L) <5 E12 E26 <5 E33 <3 <3 E21

Pheophytin a (μg/L) <5.0 <5.0 E6.0 <5.0 E11.0 E16.0 E5.3 <3.0
Appendix 2

Appendix 2—Vertical Profile Data Collected 

From the Arroyo Colorado Near Rio Hondo, 

Texas 
Blank Page
Appendix 2 41

Appendix 2–1. Water-quality monitor vertical profile data collected from the Arroyo Colorado near Rio Hondo, Texas—Continued.

USGS

 station no.

Date

and time

Sample

depth

(ft)

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

oxygen

(mg/L)

pH

(standard

 units)

Salinity

(PSU)

Turbidity

(FNMU)

Station 08470450 February data-collection period day 1

08470450 02/22/2006 10:01 1 17.7 3,480 7.7 7.8 2 190

08470450 02/22/2006 10:02 2 17.7 3,480 7.3 7.8 2 190

08470450 02/22/2006 10:03 3 17.7 3,490 7.4 7.8 2 210

08470450 02/22/2006 10:04 4 17.7 3,490 7.2 7.9 2 180

Station 08470450 February data-collection period day 2

08470450 02/23/2006 13:05 1 20.9 3,740 6.5 7.6 2 110

08470450 02/23/2006 13:06 2 20.9 3,740 6.6 7.7 2 120

08470450 02/23/2006 13:07 3 20.9 3,740 6.5 7.7 2 120

08470450 02/23/2006 13:08 4 20.9 3,740 6.5 7.7 2 120

08470450 02/23/2006 13:09 5 20.9 3,710 6.5 7.7 2 160

Station 08470450 May data-collection period day 1

08470450 05/23/2006 10:22 1 28.1 4,310 6.2 7.9 2 92

08470450 05/23/2006 10:23 2 28.1 4,310 5.5 8.0 2 93

08470450 05/23/2006 10:24 3 28.1 4,310 5.8 8.0 2 100

08470450 05/23/2006 10:25 4 28.1 4,310 5.3 8.0 2 110

Station 08470450 May data-collection period day 2

08470450 05/24/2006 10:49 1 28.3 4,350 5.0 8.0 2 100

08470450 05/24/2006 10:50 2 28.2 4,430 5.0 8.0 2 120

08470450 05/24/2006 10:51 3 28.2 4,350 4.9 8.0 2 120

08470450 05/24/2006 10:52 4 28.2 4,350 4.8 8.0 2 140

08470450 05/24/2006 10:53 5 28.2 4,350 4.8 8.0 2 140

Station 08470460 February data-collection period day 1

08470460 02/22/2006 08:55 1 17.6 4,280 7.8 7.8 2 56

08470460 02/22/2006 08:56 2 17.6 5,200 7.8 7.7 3 55

08470460 02/22/2006 08:57 3 17.5 8,130 7.0 7.7 4 53

08470460 02/22/2006 08:58 4 17.1 18,700 5.9 7.6 11 45

08470460 02/22/2006 08:59 5 16.4 47,700 1.8 7.9 31 20

08470460 02/22/2006 09:00 6 16.2 49,200 1.0 8.0 32 17

08470460 02/22/2006 09:01 7 16.1 49,800 1.1 8.1 33 18

08470460 02/22/2006 09:02 8 16.0 50,400 1.3 8.2 33 15

08470460 02/22/2006 09:03 9 15.9 50,700 1.5 8.2 33 17

08470460 02/22/2006 09:04 10 15.9 51,000 1.6 8.2 33 18

08470460 02/22/2006 09:05 11 15.8 51,200 1.6 8.2 34 15

08470460 02/22/2006 09:06 12 15.8 51,800 1.6 8.3 34 15

Station 08470460 February data-collection period day 2

08470460 02/23/2006 13:31 1 20.8 4,300 7.0 7.8 2 120

08470460 02/23/2006 13:32 2 20.7 4,360 7.0 7.8 2 70

08470460 02/23/2006 13:33 3 20.8 4,290 7.0 7.8 2 74

08470460 02/23/2006 13:34 4 20.8 4,180 7.0 7.8 2 76

08470460 02/23/2006 13:35 5 20.6 5,090 6.8 7.7 3 66

08470460 02/23/2006 13:36 6 20.6 5,830 6.7 7.7 3 65

08470460 02/23/2006 13:37 7 20.6 5,960 6.6 7.7 3 62

08470460 02/23/2006 13:38 8 20.0 14,000 5.2 7.6 8 45

08470460 02/23/2006 13:39 9 19.7 35,000 .9 7.7 22 27

08470460 02/23/2006 13:40 10 16.0 50,400 1.1 7.9 33 18

08470460 02/23/2006 13:41 11 15.9 51,500 1.1 7.9 34 19

08470460 02/23/2006 13:42 12 15.9 52,000 .8 8.0 34 20

08470460 02/23/2006 13:43 13 15.9 52,400 .8 8.0 34 22

08470460 02/23/2006 13:44 14 15.9 52,400 E.5 8.0 35 22

Appendix 2–1. Water-quality monitor vertical profile data collected from the Arroyo Colorado near Rio Hondo, Texas.

[ft, feet; °C, degrees Celsius; μS/cm, microsiemens per centimeter at 25 degrees Celsius; mg/L, milligrams per liter; PSU, practical salinity units; FNMU, formazin nephelometric units; E, estimated] 
42 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Station 08470460 May data-collection period day 1

08470460 05/23/2006 09:57 1 27.8 4,980 5.6 8.0 3 36

08470460 05/23/2006 09:58 2 27.8 5,560 5.1 7.9 3 50

08470460 05/23/2006 09:59 3 27.8 6,470 4.2 7.9 4 40

08470460 05/23/2006 10:00 4 27.8 9,620 4.1 7.9 5 43

08470460 05/23/2006 10:01 5 27.6 17,400 1.2 7.7 10 18

08470460 05/23/2006 10:02 6 27.6 18,800 E.5 7.7 11 20

08470460 05/23/2006 10:03 7 27.3 23,700 E.2 7.6 14 34

08470460 05/23/2006 10:04 8 27.2 26,800 E.1 7.8 16 28

08470460 05/23/2006 10:05 9 27.0 29,700 E.1 8.4 18 57

08470460 05/23/2006 10:06 10 26.9 32,800 E.1 8.6 21 38

08470460 05/23/2006 10:07 11 26.7 34,800 E.1 8.6 22 33

08470460 05/23/2006 10:08 12 26.6 36,300 E.1 8.5 23 27

Station 08470460 May data-collection period day 2

08470460 05/24/2006 10:07 1 28.3 6,190 3.9 8.0 3 28

08470460 05/24/2006 10:08 2 28.3 6,330 4.6 8.0 3 48

08470460 05/24/2006 10:09 3 28.0 9,620 3.0 7.9 5 31

08470460 05/24/2006 10:10 4 27.9 16,200 1.9 7.8 9 25

08470460 05/24/2006 10:11 5 27.8 18,400 .9 7.7 11 29

08470460 05/24/2006 10:12 6 27.7 20,300 E.5 7.7 12 35

08470460 05/24/2006 10:13 7 27.6 22,900 E.1 7.7 14 48

08470460 05/24/2006 10:14 8 27.4 26,300 E.1 7.8 16 57

08470460 05/24/2006 10:15 9 27.3 28,000 E.1 8.1 17 57

08470460 05/24/2006 10:16 10 27.2 29,500 E.1 8.4 18 65

08470460 05/24/2006 10:17 11 27.0 31,700 E.1 8.7 20 59

08470460 05/24/2006 10:18 12 26.8 33,900 E.1 8.7 21 48

08470460 05/24/2006 10:19 13 26.7 35,300 E.1 8.7 22 36

08470460 05/24/2006 10:20 14 26.6 37,100 E.1 8.6 23 29

Station 08470500 February data-collection period day 1

08470500 02/22/2006 10:55 1 17.4 5,310 8.5 7.7 3 28

08470500 02/22/2006 10:56 2 17.4 5,270 8.2 7.7 3 28

08470500 02/22/2006 10:57 3 17.3 5,530 8.0 7.7 3 28

08470500 02/22/2006 10:58 4 17.3 5,930 6.9 7.5 3 21

08470500 02/22/2006 10:59 5 16.4 48,600 1.9 7.8 32 13

08470500 02/22/2006 11:00 6 16.4 48,700 1.1 7.9 32 11

08470500 02/22/2006 11:01 7 15.9 50,300 1.6 8.0 33 9.8

08470500 02/22/2006 11:02 8 16.0 51,400 1.6 8.1 34 12

08470500 02/22/2006 11:03 9 16.0 53,200 1.5 8.1 35 7.7

08470500 02/22/2006 11:04 10 16.1 53,300 1.4 8.2 35 8.0

08470500 02/22/2006 11:05 11 16.3 54,000 1.1 8.2 36 6.5

08470500 02/22/2006 11:06 12 16.4 54,000 1.1 8.2 36 7.2

08470500 02/22/2006 11:07 13 16.4 54,000 1.0 8.2 36 6.8

Station 08470500 February data-collection period day 2

08470500 02/23/2006 14:05 1 19.7 14,300 7.4 7.8 8 18

08470500 02/23/2006 14:06 2 19.6 14,600 7.3 7.8 8 18

08470500 02/23/2006 14:07 3 19.6 14,800 7.2 7.8 9 19

08470500 02/23/2006 14:08 4 19.6 15,000 7.0 7.8 9 21

08470500 02/23/2006 14:09 5 19.6 15,200 6.9 7.8 9 12

08470500 02/23/2006 14:10 6 19.2 19,500 5.6 7.7 12 20

08470500 02/23/2006 14:11 7 18.7 26,400 4.4 7.7 16 18

08470500 02/23/2006 14:12 8 17.8 38,100 1.7 7.7 24 16

08470500 02/23/2006 14:13 9 16.9 48,000 .8 7.8 31 8.4

08470500 02/23/2006 14:14 10 16.5 50,300 .9 7.8 33 13

Appendix 2–1. Water-quality monitor vertical profile data collected from the Arroyo Colorado near Rio Hondo, Texas—Continued.

USGS

 station no.

Date

and time

Sample

depth

(ft)

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

oxygen

(mg/L)

pH

(standard

 units)

Salinity

(PSU)

Turbidity

(FNMU)
Appendix 2 43

Station 08470500 February data-collection period day 2—Continued

08470500 02/23/2006 14:15 11 16.1 52,300 0.9 7.9 34 12

08470500 02/23/2006 14:16 12 16.1 52,400 .9 8.0 34 9.1

08470500 02/23/2006 14:17 13 16.1 52,700 .9 8.0 35 9.4

08470500 02/23/2006 14:18 14 16.4 53,600 .7 8.0 35 7.6

Station 08470500 May data-collection period day 1

08470500 05/23/2006 09:36 1 25.5 8,970 5.1 7.9 5 11

08470500 05/23/2006 09:37 2 27.5 9,000 4.6 7.9 5 12

08470500 05/23/2006 09:38 3 27.5 9,130 3.9 7.9 5 9.9

08470500 05/23/2006 09:39 4 27.6 9,410 3.4 7.8 5 9.6

08470500 05/23/2006 09:40 5 28.0 10,600 2.6 7.8 6 11

08470500 05/23/2006 09:41 6 28.2 13,000 1.4 7.7 7 15

08470500 05/23/2006 09:42 7 27.4 21,700 E.3 7.7 13 11

08470500 05/23/2006 09:43 8 27.1 23,600 E.3 7.8 14 14

08470500 05/23/2006 09:44 9 26.8 29,600 E.2 8.5 18 18

08470500 05/23/2006 09:45 10 26.6 35,400 E.2 8.6 22 16

Station 08470500 May data-collection period day 2

08470500 05/24/2006 09:26 1 27.8 10,300 4.0 7.9 6 15

08470500 05/24/2006 09:27 2 27.9 11,100 4.0 7.9 6 19

08470500 05/24/2006 09:28 3 27.8 12,600 3.1 7.9 7 19

08470500 05/24/2006 09:29 4 27.7 16,400 1.4 7.8 10 23

08470500 05/24/2006 09:31 5 27.5 19,500 .7 7.8 12 30

08470500 05/24/2006 09:32 6 27.4 21,400 E.5 7.8 13 30

08470500 05/24/2006 09:33 7 27.3 23,400 E.2 7.8 14 39

08470500 05/24/2006 09:34 8 27.2 25,300 E.1 7.8 15 50

08470500 05/24/2006 09:35 9 27.1 27,400 E.1 7.9 17 54

08470500 05/24/2006 09:36 10 26.9 29,900 E.1 8.4 19 52

08470500 05/24/2006 09:37 11 26.2 31,000 E.1 8.7 19 48

Station 08470520 February data-collection period day 1

08470520 02/22/2006 11:16 1 17.7 6,330 8.7 7.8 3 34

08470520 02/22/2006 11:17 2 17.7 6,410 8.3 7.8 3 24

08470520 02/22/2006 11:18 3 17.6 6,400 7.7 7.8 3 26

08470520 02/22/2006 11:19 4 17.5 10,800 7.3 7.7 6 21

08470520 02/22/2006 11:20 5 17.0 12,200 6.0 7.8 7 22

08470520 02/22/2006 11:21 6 16.8 46,600 2.3 7.8 30 7.6

08470520 02/22/2006 11:22 7 16.6 52,700 1.1 8.0 35 6.1

08470520 02/22/2006 11:23 8 17.1 52,100 1.1 7.9 34 6.1

08470520 02/22/2006 11:24 9 17.0 54,700 .9 8.2 36 7.7

08470520 02/22/2006 11:25 10 16.9 54,600 .9 8.2 36 6.2

08470520 02/22/2006 11:26 11 16.9 55,100 .9 8.2 36 5.0

08470520 02/22/2006 11:27 12 17.1 55,000 .7 8.2 36 5.3

08470520 02/22/2006 11:28 13 17.1 55,200 .6 8.3 37 4.5

08470520 02/22/2006 11:29 14 17.1 55,200 .7 8.3 37 5.1

Station 08470520 February data-collection period day 2

08470520 02/23/2006 14:46 1 19.4 12,400 8.5 7.9 7 12

08470520 02/23/2006 14:47 2 19.3 12,400 8.5 7.9 7 15

08470520 02/23/2006 14:48 3 19.3 12,600 8.5 8.0 7 15

08470520 02/23/2006 14:49 4 19.3 12,900 8.1 7.9 7 16

08470520 02/23/2006 14:50 5 19.2 16,100 7.7 7.9 9 15

08470520 02/23/2006 14:51 6 18.7 34,100 5.0 7.8 21 12

08470520 02/23/2006 14:52 7 16.0 50,400 2.0 7.8 33 5.9

08470520 02/23/2006 14:53 8 16.1 50,700 1.4 7.9 33 8.3

08470520 02/23/2006 14:54 9 16.0 51,400 1.4 7.9 34 5.6

Appendix 2–1. Water-quality monitor vertical profile data collected from the Arroyo Colorado near Rio Hondo, Texas—Continued.

USGS

 station no.

Date

and time

Sample

depth

(ft)

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

oxygen

(mg/L)

pH

(standard

 units)

Salinity

(PSU)

Turbidity

(FNMU)
44 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Station 08470520 February data-collection period day 2—Continued

08470520 02/23/2006 14:55 10 16.1 52,500 1.3 8.0 35 6.4

08470520 02/23/2006 14:56 11 16.4 53,200 1.0 8.0 35 7.5

08470520 02/23/2006 14:57 12 16.8 54,400 E.5 8.1 36 6.6

08470520 02/23/2006 14:58 13 16.9 54,600 E.4 8.1 36 6.4

08470520 02/23/2006 14:59 14 17.0 54,700 E.4 8.1 36 6.5

08470520 02/23/2006 15:00 15 17.0 54,800 E.4 8.1 36 6.4

Station 08470520 May data-collection period day 1

08470520 05/23/2006 09:10 1 27.5 8,040 7.5 7.9 4 24

08470520 05/23/2006 09:11 2 27.5 8,510 6.6 7.8 5 18

08470520 05/23/2006 09:12 3 27.7 8,430 5.3 7.8 5 17

08470520 05/23/2006 09:13 4 27.8 10,500 3.2 7.5 6 14

08470520 05/23/2006 09:14 5 28.0 12,200 .9 7.5 7 13

08470520 05/23/2006 09:15 6 27.9 17,000 E.4 7.4 10 11

08470520 05/23/2006 09:16 7 27.5 22,000 E.3 7.4 13 7.4

08470520 05/23/2006 09:17 8 26.7 29,200 E.2 8.5 18 14

08470520 05/23/2006 09:18 9 26.7 31,500 E.2 8.6 20 13

08470520 05/23/2006 09:19 10 26.4 35,500 E.2 8.7 22 11

08470520 05/23/2006 09:20 11 25.9 43,100 E.2 9.0 28 16

08470520 05/23/2006 09:21 12 25.9 43,300 E.2 9.1 28 15

08470520 05/23/2006 09:22 13 25.7 43,900 E.2 9.1 28 16

08470520 05/23/2006 09:23 14 25.7 44,000 E.2 9.1 28 14

08470520 05/23/2006 09:24 15 25.7 44,100 E.1 9.1 28 16

Station 08470520 May data-collection period day 2

08470520 05/24/2006 07:40 1 27.8 7,920 6.7 8.0 4 17

08470520 05/24/2006 07:41 2 28.1 8,240 6.2 8.0 5 15

08470520 05/24/2006 07:42 3 28.3 8,740 6.0 8.0 5 13

08470520 05/24/2006 07:43 4 28.4 9,350 4.7 7.9 5 12

08470520 05/24/2006 07:44 5 28.4 11,800 3.0 7.7 7 9.9

08470520 05/24/2006 07:45 6 28.1 15,500 E.4 7.5 9 8.4

08470520 05/24/2006 07:46 7 27.8 18,400 E.2 7.5 11 17

08470520 05/24/2006 07:47 8 27.4 24,200 E.2 7.5 15 17

08470520 05/24/2006 07:48 9 26.5 36,500 E.2 8.7 23 12

08470520 05/24/2006 07:49 10 25.7 44,500 E.1 9.4 29 16

08470520 05/24/2006 07:50 11 25.5 44,900 E.1 9.4 29 15

08470520 05/24/2006 07:51 12 25.5 45,000 E.1 9.5 29 18

08470520 05/24/2006 07:52 13 25.5 45,000 E.1 9.5 29 16

08470520 05/24/2006 07:53 14 25.5 45,000 E.1 9.5 29 17

08470520 05/24/2006 07:54 15 25.5 45,100 E.1 9.5 29 16

Appendix 2–1. Water-quality monitor vertical profile data collected from the Arroyo Colorado near Rio Hondo, Texas—Continued.

USGS

 station no.

Date

and time

Sample

depth

(ft)

Temperature

(°C)

Specific

conductance

(μS/cm)

Dissolved

oxygen

(mg/L)

pH

(standard

 units)

Salinity

(PSU)

Turbidity

(FNMU)
Appendix 2 45

Appendix 2–2. PAR sensor vertical profile data collected from the Arroyo Colorado near Rio Hondo, Texas—Continued.

Appendix 2–2. PAR sensor vertical profile data collected from the Arroyo Colorado near Rio Hondo, Texas.

[PAR, photosynthetically active radiation; m, meters; μE/m2/s, microEinsteins per square meter per second]

USGS

station no.

Date and

time

Sample

depth

(m)

Remark Downwelling light

(μE/m2

/sec)

Upwelling light

(μE/m2

/sec)

Station 08470450 February data-collection period

08470450 02/22/2006 14:20 0 Air 1,774.00 152.00

08470450 02/22/2006 14:21 0 Surface 644.00 29.00

08470450 02/22/2006 14:22 1 Water 11.00 .60

08470450 02/22/2006 14:23 2 Water .01 .00

Station 08470450 May data-collection period

08470450 05/23/2006 14:20 0 Air 2,430.00 109.10

08470450 05/23/2006 14:21 0 Surface 1,274.00 38.01

08470450 05/23/2006 14:22 1 Water 2.30 .20

08470450 05/23/2006 14:23 2 Water .00 .00

Station 08470460 February data-collection period

08470460 02/22/2006 10:22 0 Air 207.00 22.00

08470460 02/22/2006 10:23 0 Surface 82.00 12.00

08470460 02/22/2006 10:24 1 Water 25.00 3.00

08470460 02/22/2006 10:25 2 Water 3.00 .03

08470460 02/22/2006 10:26 3 Water 1.00 .20

08470460 02/22/2006 10:27 4 Water .30 .04

08470460 02/22/2006 14:32 0 Air 837.00 126.00

08470460 02/22/2006 14:33 0 Surface 399.00 19.00

08470460 02/22/2006 14:34 1 Water 41.00 4.00

08470460 02/22/2006 14:35 2 Water 4.70 .60

08470460 02/22/2006 14:36 3 Water .80 .10

08470460 02/22/2006 14:37 4 Water .40 .06

08470460 02/22/2006 16:08 0 Air 940.00 182.00

08470460 02/22/2006 16:09 0 Surface 544.00 51.00

08470460 02/22/2006 16:10 1 Water 83.00 7.00

08470460 02/22/2006 16:11 2 Water 13.00 1.40

08470460 02/22/2006 16:12 3 Water 2.80 .30

08470460 02/22/2006 16:13 4 Water .40 .06

Station 08470460 May data-collection period

08470460 05/23/2006 10:22 0 Air 1,820.00 137.00

08470460 05/23/2006 10:23 0 Surface 275.00 48.00

08470460 05/23/2006 10:24 1 Water 7.20 1.60

08470460 05/23/2006 10:25 2 Water .43 .09

08470460 05/23/2006 10:26 3 Water .02 .00

08470460 05/23/2006 10:27 4 Water .00 .00

Station 08470500 February data-collection period

08470500 02/22/2006 10:48 0 Air 856.00 85.00

08470500 02/22/2006 10:49 0 Surface 425.00 43.00

08470500 02/22/2006 10:50 1 Water 114.00 12.00

08470500 02/22/2006 10:51 2 Water 13.00 1.10

08470500 02/22/2006 10:52 3 Water 3.60 .40

08470500 02/22/2006 10:53 4 Water 1.40 .10
46 Water-Quality and Ancillary Data Collected From the Arroyo Colorado Near Rio Hondo, Texas, 2006

Prepared by the USGS Texas Water Science Center:

8027 Exchange Drive

Austin, TX 78754–4733

Information regarding water resources in Texas is available at 

http: //tx.usgs.gov/

Station 08470500 February data-collection period—Continued

08470500 02/22/2006 14:02 0 Air 1,127.00 142.00

08470500 02/22/2006 14:03 0 Surface 544.00 53.00

08470500 02/22/2006 14:04 1 Water 132.00 14.00

08470500 02/22/2006 14:05 2 Water 8.00 .90

08470500 02/22/2006 14:06 3 Water 2.20 .20

08470500 02/22/2006 14:07 4 Water .70 .09

08470500 02/22/2006 16:28 0 Air 814.00 139.00

08470500 02/22/2006 16:29 0 Surface 441.00 47.00

08470500 02/22/2006 16:30 1 Water 115.00 9.00

08470500 02/22/2006 16:31 2 Water 16.00 1.00

08470500 02/22/2006 16:32 3 Water 3.80 .30

Station 08470500 May data-collection period

08470500 05/23/2006 10:48 0 Air 477.00 69.00

08470500 05/23/2006 10:49 0 Surface 276.00 53.00

08470500 05/23/2006 10:50 1 Water 36.00 8.90

08470500 05/23/2006 10:51 2 Water 15.00 2.30

08470500 05/23/2006 10:52 3 Water 2.80 .35

08470500 05/23/2006 10:53 4 Water .58 .05

Station 08470520 February data-collection period

08470520 02/22/2006 13:30 0 Air 1,633.00 174.00

08470520 02/22/2006 13:31 0 Surface 938.00 91.00

08470520 02/22/2006 13:32 1 Water 217.00 26.00

08470520 02/22/2006 13:33 2 Water 23.00 2.80

08470520 02/22/2006 13:34 3 Water 4.10 .40

08470520 02/22/2006 13:35 4 Water 1.40 .10

Station 08470520 May data-collection period

08470520 05/23/2006 13:30 0 Air 1,737.00 26.07

08470520 05/23/2006 13:31 0 Surface 148.10 3.20

08470520 05/23/2006 13:32 1 Water 3.46 .51

08470520 05/23/2006 13:33 2 Water .36 .04

08470520 05/23/2006 13:34 3 Water .08 .01

Appendix 2–2. PAR sensor vertical profile data collected from the Arroyo Colorado near Rio Hondo, Texas—Continued.

USGS

station no.

Date and

time

Sample

depth

(m)

Remark Downwelling light

(μE/m2

/sec)

Upwelling light

(μE/m2/sec)