STUDY DESIGN AND DATA COLLECTION

The primary objective of the stream chemistry component was to assess the relationship between land use and chemical constituents of surface water. Surface-water sites were distributed among land uses; site types include basic, intensive, and synoptic sites for pesticides, nutrients, and trace elements.

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The primary objective of the stream ecology component was to assess surface-water quality by integrating the physical, chemical, and biological factors. Ecology sites were distributed among forest, irrigated agriculture, urban, and rangeland. Sites were classified as either intensive or synoptic on the basis of the level of the sampling effort or the number of years data were collected. A special study on the applicability of transplanted bryophytes (moss) for trace-element accumulation was also conducted.

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The primary objective of the ground-water chemistry component was to determine if the chemical constituents in the shallow aquifer were related to urban and irrigated agricultural land use. A subunit survey of a deeper aquifer used for domestic supply was also conducted.

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Bed-sediment study

Determine presence of potentially toxic compounds attached to sediments in major streams.

Sample depositional zones of the Rio Grande and selected tributaries and non-tributaries for trace elements and hydrophobic organic compounds.

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1
1992-93

Water chemistry -- Basic Fixed Site study

Describe concentrations and loads of chemicals, suspended sediment, and nutrients at selected sites throughout the Study Unit.

Sample at or near sites where streamflow is measured continuously for major constituents, nutrients, and suspended sediment.

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Monthly,
April 1993-

Sept. 1995

Water chemistry -- Intensive Fixed Site study

Determine concentration and timing of pesticides transported by runoff to streams.

Select an agricultural basin where pesticides, dissolved solids, major constituents, and nutrients were sampled weekly and during selected runoff events.

1

Weekly,
April-Sept.

1994

Water chemistry -- Trace-element synoptic study

Describe presence and distribution of trace elements in the water column, suspended sediment, and bed material in the Rio Grande and tributaries in the northern part of the Study Unit.

Sample water column and suspended sediment during high flow (June) and water column and bed material during low flow (September) for trace elements and major constituents.

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1

1994

Water chemistry--
Mesilla Valley pesticide and nutrient synoptic study

Describe presence and distribution of pesticides and nutrients in the water column in the Rio Grande and drains in the Mesilla Valley.

Sample water column during high flow (irrigation season) for pesticides, nutrients, dissolved solids, and major constituents and during low flow (nonirrigation season) for pesticides, nutrients, dissolved solids, major constituents, and trace elements. Sample bed material in drains during low flow for pesticides.

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1

1994-95

Water chemistry--Rincon Valley temporal drain study

Describe temporal water-quality variation in surface drains and Rio Grande in an agricultural area flood irrigated with surface water.

Sample selected sites twice during nonirrigation season (low flow) and at the beginning and end of the irrigation season (high flow). Water analyzed for dissolved solids, major constituents, nutrients, organic carbon, trace elements, and pesticides.

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4

1994-95

Fish-tissue contaminant study

Determine the presence of contaminants in fish tissue from species that can be found in most streams of the Study Unit.

Sample composites of whole-body fish for:

hydrophobic organic contaminants

fish livers for trace elements.

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12

1
1992-93

Intensive ecological assessments

Assess fish, macroinvertebrates, and algae communities and habitat in streams representing three ecological regions.

Sample aquatic communities at a subset of water-chemistry basic sites; quantitatively describe stream habitat for these organisms.

Sample aquatic communities at a subset of water-chemistry basic sites; quantitatively describe stream habitat for these organisms.

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8

3 reaches/ site in 1995;

1 reach/year,

1993-95

Ecological synoptic studies

Assess aquatic and terrestrial communities and habitat in representative streams throughout the Study Unit.

Sample macroinvertebrates and algae at or near water-chemistry sites and describe habitat.

Sample adult insects using ultraviolet light traps at or near water-chemistry sites.

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14

1

1994-95

Transplanted aquatic bryophyte study

Determine spatial distribution of trace elements in the upper Rio Grande Valley Study Unit using transplanted aquatic bryophytes.

Transplant bryophyte samples (Hygrohypnum ochraceum) for variable lengths of time and analyze samples for trace-element concentration.

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1

1994

Land-use studies

Examine natural and human factors that affect the quality of shallow ground water that underlies areas of urban land, overhead, center-pivot sprinkler-irrigated agriculture land, or flood-irrigated agricultural land.

Install shallow wells and sample water from wells for analysis of dissolved solids, major constituents, nutrients, dissolved organic carbon, trace elements, pesticides, volatile organic compounds, and radionuclides.

(1) San Luis Valley agricultural land-use study of an area irrigated with ground water by overhead, center-pivot sprinklers.

(2) Albuquerque urban land-use study.

(3) Rincon Valley agricultural land-use study of an area flood irrigated with surface water.

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30

1993

1993

1994

Aquifer subunit survey

Describe the overall water quality in the part of the basin-fill aquifer used for domestic supply, public supply, or irrigation.

Randomly select and sample existing wells located in the Rio Grande flood plain from Cochiti Lake, New Mexico, to El Paso, Texas, for analysis of major constituents, nutrients, dissolved organic carbon, trace elements, pesticides, volatile organic compounds, and radionuclides.

30

1

1995