Event and Base Flow in Subsurface Drainage Dataset

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This dataset contains simulated subsurface drainage discharge data used to characterize event flow and baseflow dynamics under long-term hydroclimatic conditions. The data were generated using continuous hydrologic simulation to evaluate drainage responses to precipitation events and groundwater contributions in a humid, subsurface-drained agricultural setting.

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Description of the Data and File Structure

This dataset consists of three comma-separated value (CSV) files derived from a single long-term subsurface drainage simulation. Files are structured to support analysis of drainage discharge at hourly and daily temporal resolutions and to facilitate testing, validation, and reuse of event–baseflow separation approaches.

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Files Included in This Dataset

50_Years_DRAINMOD_TEST_DATA.csv

Contains continuous simulated subsurface drainage output generated using the DRAINMOD model. This file represents the complete simulation record and serves as the primary dataset for event and baseflow classification analyses under fixed soil, crop, climate, and drainage conditions.

7_Years_DRAINMOD_TEST_DATA.csv

Contains continuous simulated subsurface drainage output generated using the DRAINMOD model. This file represents the complete simulation record and serves as the primary dataset for event and baseflow classification analyses under fixed soil, crop, climate, and drainage conditions.

Random_Daily_Data_Sample.csv

A daily-resolution subset randomly sampled from the full simulation period. This file is intended for exploratory analysis, methodological testing, and demonstration of daily-scale event and baseflow separation without requiring the full dataset.

Random_Hourly_Data_Sample.csv

An hourly-resolution subset randomly sampled from the full simulation output. This file preserves short-term hydrologic variability and is suitable for examining event timing, peak drainage response, and fine-scale separation of event flow and baseflow.

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Relationships Between Files

All three files originate from the same simulated hydrologic system and share identical variable definitions, units of measurement, and classification logic. The daily and hourly sample files are direct subsets of the full simulation output and are provided to support rapid testing, reproducibility, and educational reuse.

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Simulation Settings and Assumptions

Weather and Climate Inputs

• Daily historical precipitation and potential evapotranspiration data from Plymouth, North Carolina
• Continuous simulation period from January 1, 1951 through December 31, 1990

Soil Parameters

• Portsmouth E soil profile with layer-specific hydraulic properties
• Saturated hydraulic conductivity: 2.5 cm day⁻¹
• Initial water table depth: 50 cm below the soil surface
• No deep seepage or lateral groundwater inflow assumed

Drainage System Configuration

• Drain depth: 1.0 m below the soil surface
• Drain spacing: 20 m
• Conventional subsurface drainage layout

Crop and Management Conditions

• Continuous corn production throughout the 50-year simulation
• No additional management practices beyond standard DRAINMOD defaults

These assumptions were selected to represent a typical subsurface-drained agricultural field in a humid region and to enable consistent evaluation of long-term event flow and baseflow behavior.

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Variables and Definitions

All variables are consistently defined across files. Units are provided to ensure direct interpretation and reuse.

(Essential model Data)

Date

Date and time of each observation.

• Format: MM/DD/YYYY (daily files) or MM/DD/YYYY HH:MM (hourly files)

Flow

Simulated subsurface drainage discharge rate.

• Units: depth per unit time (cm/day or cm/hour)
• Represents drainage flux normalized by the contributing drained area, expressed as an equivalent depth of water leaving the system over time. This is not a volumetric discharge (e.g., m³/s), but a depth-normalized flux that enables comparison across sites and conditions independent of drainage area.

Concentration

This tells the concentration of the nutrient exiting the drainage pipe (eg. Nitrogen, Phosphorus e.t.c)

• Units: milligram/L (mg/L)

It is important to note that if you do not have concentration data, leave the concentration column blank.

Additional data set (not essential for performing event Analysis)

Water table

Simulated depth to the water table measured below the soil surface.

• Units: centimeters (cm)
• Positive values indicate depth below the soil surface and negative values will be ponding
• Represents water table position influencing event flow contributions (shallower water tables are observed during events)

temperature

Soil water temperature, this helps us get the average soil temperature during events.

• Units: degrees Celsius (°C)

resolution

all data resolution should be consistent and either be in hourly or Daily resolution.

• Values: hourly or daily

missing_data

Missing or invalid observations.

• Represented as blank cells
• No inputed values are included

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Definitions of Hydrologic Terms

Event Flow
Periods of elevated subsurface drainage discharge primarily driven by precipitation-related inputs such as rainfall or snowmelt.

Baseflow
The sustained component of drainage discharge supplied mainly by groundwater contributions outside of storm-driven periods.

Event Period
A time interval classified as event flow, beginning when discharge exceeds a defined threshold and ending when discharge returns to baseline conditions.

Baseflow Period
A time interval during which discharge remains below the event threshold and reflects groundwater-dominated drainage conditions.

Event Threshold
A discharge magnitude or rate-of-change criterion used to distinguish event flow from baseflow. Thresholds were determined using consistent, site-specific hydrologic criteria applied uniformly across the dataset.

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Sharing and Access Information

This dataset is publicly available through the Dryad Digital Repository.

• Dataset DOI: https://doi.org/10.5061/dryad.t1g1jwtgs
• Repository: Dryad

No additional external data sources are required to use this dataset.

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Code and Software

No executable scripts are included in this submission. All files are provided in CSV format.

Compatible software includes:

• Microsoft Excel or equivalent spreadsheet software
• R, Python, MATLAB, or other statistical and scientific computing environments capable of reading CSV files

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Dataset Readiness Statement

All variables are explicitly defined with units of measurement and consistent interpretation across files. The dataset is fully documented to support transparency, reproducibility, and reuse in hydrologic, agricultural drainage, and environmental modeling research.