Daren Harmel

Dr. Daren Harmel

orcid

Research Focus & Metrics

Academic Career Length

22Years (2005-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 November 2008 in Journal of Environmental Quality
Verified
Journal Article
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DHDaren Harmel
Daren Harmel
Song QianSong Qian
Song Qian
KRKen Reckhow
Ken Reckhow
PCPamela Casebolt
Pamela Casebolt

30 August 2023 in Water
Verified
Journal Article
Open access
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DHDaren Harmel
Daren Harmel
HPHeather E Preisendanz
Heather E Preisendanz
KKKevin Wayne King
Kevin Wayne King
DBDennis Busch
Dennis Busch
FBFrancois Birgand
Francois Birgand
DSDebabrata Sahoo
Debabrata Sahoo
Technological advances and resource constraints present scientists and engineers with renewed challenges in the design of methods to conduct water quality monitoring, and these decisions ultimately determine the degree of project success. Many professionals are exploring alternative lower-cost options because of cost constraints, and research and development is largely focused on in situ sensors that produce high temporal resolution data. While some guidance is available, contemporary information is needed to balance water quality monitoring decisions with financial and personnel constraints, while meeting data quality needs. This manuscript focuses on monitoring constituents, such as sediment, nutrients, and pathogens, at the field scale and in small watersheds. Specifically, the impacts on the costs and data quality of alternatives related to site selection, discharge measurement, and constituent concentration measurement, are explored. The present analysis showed that avoiding sites requiring extensive berm construction and the installation of electric power to reach distant sites greatly reduces the initial costs with little impact on data quality; however, other decisions directly impact data quality. For example, proper discharge measurement, high-frequency sampling, frequent site and equipment maintenance, and the purchase of backup power and monitoring equipment can be costly, but are important for high quality data collection. In contrast, other decisions such as the equipment type (mechanical samplers, electronic samplers, or in situ sensors) and whether to analyze discrete or composite samples greatly affect the costs, but have minimal impact on data quality. These decisions, therefore, can be based on other considerations (e.g., project goals, intended data uses, funding agency specifications, and agency protocols). We hope this guidance helps practitioners better design and implement water quality monitoring to satisfy resource constraints and data quality needs.

17 July 2017 in Water
Verified
Journal Article
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JTJuan Tian
Juan Tian
GDGuiming Dong
Guiming Dong
RKRaghupathy Karthikeyan
Raghupathy Karthikeyan
LLLin Li
Lin Li
DHDaren Harmel
Daren Harmel
In flooded areas, soils are often exposed to standing water and subsequent drainage, thus over fertilization can release excess phosphorus (P) into surface water and groundwater. To investigate P release and transformation processes in flooded alkaline soils, wheat-growing soil and vegetable-growing soil were selected. We flooded-drained-reflooded two soils for 35 d, then drained the soils, and 10 d later reflooded the soils for 17 d. Dissolved reactive phosphorus (DRP), soil inorganic P fractions, Olsen P, pH, and Eh in floodwater and pore water were analyzed. The wheat-growing soil had significantly higher floodwater DRP concentrations than vegetable-growing soil, and floodwater DRP in both soils decreased with the number of flooding days. During the reflooding period, DRP in overlying floodwater from both soils was less than 0.87 mg/L, which was 3–25 times less than that during the flooding period. Regardless of flooding or reflooding, pore water DRP decreased with flooding days. The highest concentration of pore water DRP observed at a 5-cm depth. Under the effect of fertilizing and flooding, the risk of vertical P movement in 10–50 cm was enhanced. P diffusion occurred from the top to the bottom of the soils. After flooding, Al-P increased in both soils, and Fe-P, O-P, Ca2-P decreased, while Fe-P, Al-P, and O-P increased after reflooding, When Olsen P in the vegetable-growing soil exceeded 180.7 mg/kg and Olsen P in the wheat-growing soil exceeded 40.8 mg/kg, the concentration of DRP in pore water increased significantly. Our results showed that changes in floodwater and pore water DRP concentrations, soil inorganic P fractions, and Olsen P are significantly affected by fertilizing and flooding; therefore, careful fertilizer management should be employed on flooded soils to avoid excess P loss.

1 September 2010 in Journal of Environmental Quality
Verified
Journal Article
Closed access
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DHDaren Harmel
Daren Harmel
RSR. M. Slade
R. M. Slade
RHR.L. Haney
R.L. Haney

4 September 2014 in Water Resources Research
Verified
Journal Article
Open access
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DHDaren Harmel
Daren Harmel
RHRichard L. Haney
Richard L. Haney
DSDouglas R. Smith
Douglas R. Smith
MWMichael White
Michael White
KKKevin W. King
Kevin W. King
The 75 year legacy database including discharge, sediment loss, land management, and meteorological data for the USDA‐ARS Riesel Watersheds, Riesel, TX, USA has been available on the web for more than a decade (www.ars.usda.gov/spa/hydro‐data) and used in numerous studies and publications; however, only recently have these data been added to the Sustaining the Earth's Watersheds, Agricultural Research Data System (STEWARDS) database (www.nrrig.mwa.ars.usda.gov/stewards/stewards.html). In addition, water quality data including dissolved inorganic N and P compounds measured from more than 1000 storm runoff events, 1300 base flow sampling events (lateral subsurface return flow or seepage flow), and 157 precipitation events through 2012 were added. The objectives of this manuscript are to present relevant background information on these data, summarize the data collection and analysis methodology, present the measured data along with cursory analyses, and convey the commitment of the USDA‐ARS Riesel Watersheds to long‐term data accessibility and database enhancement for water quality data and research.

1 December 2008 in Journal of Applied Poultry Research
Verified
Journal Article
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DHDaren Harmel
Daren Harmel
BHB. Harmel
B. Harmel
MPM. C. Patterson
M. C. Patterson
The profitability of using poultry litter as a fertilizer and soil amendment in cultivated agriculture was evaluated with the hopes of determining an