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New Mexico Water Science Center |
U.S. GEOLOGICAL SURVEY
Scientific Investigations Report 2005-5118
By Jeff B. Langman and Emma O. Nolan
The City of Albuquerque plans to divert San Juan-Chama Project water from the
Rio Grande for potable water use. This report examines streamflow and water-quality
trends in the Rio Chama and the Rio Grande for water years 1985 to 2002 following
the implementation of reservoir storage agreements in northern and central New
Mexico. Streamflow/water-quality stations used for this study include the Rio
Grande stations of Taos, Otowi, San Felipe, and Albuquerque and the Rio Chama
station of Chamita.
Water years 1985 to 2002 were a period of larger than average precipitation
and streamflow compared to the stations. historical averages. Annual precipitation
and streamflow trended downward during the study period because of a drought
during 1999 to 2002. Streamflow in the Rio Chama and Rio Grande was divided
into three distinct seasonal periods that corresponded to natural and anthropogenic
influences: fall/winter baseflow (November through February), snowmelt runoff
(March through June), and the irrigation/monsoon (July through October) seasons.
A calcium bicarbonate water type was evident at all study area stations on the
Rio Chama and Rio Grande. Specific conductance increased downstream, but alkalinity
and pH did not substantially change in the downstream direction. Nearly all
nitrogen and phosphorous concentrations were less than 1 milligram per liter
for all stations. Median trace-element concentrations and maximum radionuclide
concentrations did not exceed drinking-water standards. Anthropogenic compounds
were infrequently detected in the Rio Chama and Rio Grande, and concentrations
did not exceed drinking-water standards.
Water quality in the Rio Chama and Rio Grande varied spatially and temporally
during water years 1985 to 2002. Specific conductance increased downstream in
the Rio Grande during the fall/winter baseflow and snowmelt runoff seasons but
was similar at the Taos, Otowi, and San Felipe stations during the irrigation/monsoon
season. This similarity was a result of the release of stored water from Abiquiu
Reservoir and Cochiti Lake, which masked the natural influences that increased
specific conductance in the downstream direction during the other seasons. During
all seasons, pH decreased and major ion concentrations remained stable at the
Albuquerque station compared with the San Felipe station, but no single influence
could be identified that caused these conditions. Manganese and uranium concentrations
at the Otowi and San Felipe stations were largest during the fall/winter baseflow
and smallest during the snowmelt runoff, indicating that ground-water inflows
likely influenced these concentrations.
Water-quality temporal trends were evaluated for selected constituents during the study period and during the individual seasons. Downward trends in major ion concentrations were similar in magnitude at the Taos and Otowi stations, indicating that an upstream influence and (or) the downward trend in annual precipitation was the main reason(s) for these trends. The stations most affected by reservoirs, Chamita and San Felipe, were the only stations at which downward trends in major ions were apparent for flow-adjusted concentrations but not for seasonally correlated low-adjusted concentrations, which indicates fewer seasonal differences at these stations due to reservoir operations.
TABLE OF CONTENTS
Abstract
Introduction
Purpose and scope
Description of the study
area
Physiography
Climate
Streamflow
of the Rio Chama and Rio Grande
Influences
on streamflow and water quality in the study area
Reservoirs
Tributaries
Ground-water
inflows and outflows
Evapotranspiration
Irrigation
diversions and inflow
Previous
studies
Acknowledgment
Methods of analysis
Water-quality
spatial trend analysis
Streamflow
and water-quality seasonal trend analysis
Streamflow
and water-quality temporal trend analysis
Streamflow trends of the Rio Chama and Rio Grande, water years 1985 to 200
Seasonal trends in streamflow
Temporal trends in climate
and streamflow
Water-quality trends of the Rio Chama and Rio Grande, water years 1985 to 2002
Water-quality spatial
trends
Basic
water chemistry and physical properties
Major
ions
Nutrients,
organic carbon, and bacteria
Trace
elements
Radionuclides
Anthropogenic
compounds
Water-quality seasonal
trends
Basic
water chemistry and physical properties
Major
ions
Nutrients,
organic carbon, and bacteria
Trace
elements
Radionuclides
Water-quality temporal
trends
Summary
References cited
Supplemental information: Summary statistics and listing of analyzed anthropogenic
compounds
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For more information about USGS activities in New Mexico contact:
Director
U.S. Geological Survey
Water Science Center
5338 Montgomery Blvd, NE
Suite 400
Albuquerque, New Mexico, 87109
Telephone: (505) 830-7900
Fax: (505) 830-7998
or access the USGS Water Resources of New Mexico home page at: http://nm.water.usgs.gov/
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