Preliminary estimates of the quantity and quality of groundwater discharge to a section of Bear Creek in central Iowa

Conference · Fri Apr 01 00:00:00 EST 1994 · Geological Society of America, Abstracts with Programs; (United States)

OSTI ID:7144956

Caron, G A; Simpkins, W W; Schultz, R C ^[1]

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1. Iowa State Univ., Ames, IA (United States)

Studies in Iowa and elsewhere in the Midwest have suggested that most agrichemicals enter surface water through runoff events of tile drainage. Although it also contains agrichemicals, groundwater's contribution to surface water contamination is largely unknown, particularly in till-dominated watersheds. The purpose of this study was to estimate the quantity and quality of groundwater discharge to a 1,000-m-long section of Bear Creek in central Iowa. The study is part of a larger project that is evaluating constructed, multi-species riparian buffer strips as a Best Management Practice for agriculture. Groundwater discharge to the creek was estimated using: (1) differences in discharge between an upstream and downstream weir (minus tile drain outflow), (2) seepage meter data from the creek bed, and (3) Darcy's Law, using hydraulic gradient and K data from piezometers adjacent to the creek and minipiezometers in the creek. The authors preliminary estimates show groundwater discharge rates of 2 to 15 L/s (weirs), 10 L/s (seepage meters), and 3 L/s (Darcy's Law). Discharge in Bear Creek ranged from 100 to 400 L/s during the period; thus, groundwater contributed only a small part of the total creek discharge. Water samples from minipiezometers beneath the creek bed are characterized by NO[sub 3]-N concentrations < 3 mg/L and atrazine concentrations < 0.1 [mu]g/L. In contrast, water samples from Bear Creek typically show NO[sub 3]-N concentrations > 20 mg/L and atrazine concentrations up to 1.0 [mu]g/L. These water quality data suggest that groundwater may not be a significant contributor to agrichemical contamination of surface water in this till-dominated watershed.

• OSTI ID: 7144956
• Report Number(s): CONF-9404217-; CODEN: GAAPBC
• Journal Information: Geological Society of America, Abstracts with Programs; (United States), Vol. 26:5; Conference: 27. annual conference of the North-Central Section of the Geological Society of America (GSA), Kalamazoo, MI (United States), 28-29 Apr 1994; ISSN 0016-7592
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
AGRICULTURAL WASTES
ENVIRONMENTAL TRANSPORT
IOWA
STREAMS
GEOCHEMICAL SURVEYS
WATER POLLUTION
GROUND WATER
DEVELOPED COUNTRIES
HYDROGEN COMPOUNDS
MASS TRANSFER
NORTH AMERICA
ORGANIC WASTES
OXYGEN COMPOUNDS
POLLUTION
SURFACE WATERS
SURVEYS
USA
WASTES
WATER
540250* - Environment
Terrestrial- Site Resource &amp; Use Studies- (1990-)
540350 - Environment
Aquatic- Site Resource &amp; Use Studies- (1990-)