ms_calc_load: Calculate annual solute loads (i.e. cumulative fluxes)

In MacroSHEDS/macrosheds: Tools for interfacing with the MacroSheds dataset

Calculate annual solute loads (i.e. cumulative fluxes)

Description

Determines solute loads from daily stream discharge and corresponding chemistry data using any of five available methods. For daily stream/precip solute fluxes, see ms_calc_flux().

Usage

ms_calc_load(chemistry, q, method = "all", verbose = TRUE)

Arguments

chemistry	A data.frame of stream chemistry data in MacroSheds format (see details) and in units of mg/L.
q	A data.frame of stream discharge (L/s) in MacroSheds format (see details).
method	character vector. Any combination of: "pw", "rating", "composite", "beale", "average". Use "all" to run every method. See details.
verbose	logical. FALSE for less frequent informational messaging.

Details

MacroSheds format (only date, site_code, var, and val are required in inputs to this function):

column	definition
date	Date in YYYY-mm-dd
site_code	A unique identifier for each MacroSheds site, identical to primary source site code where possible. See ms_load_sites().
grab_sample	Boolean integer indicating whether the observation was obtained via grab sample or installed sensor. 1 = TRUE (grab sample), 0 = FALSE (installed sensor).
var	Variable code. See ms_load_variables().
val	Data value. See ms_load_variables() for units.
ms_status	Boolean integer. 0 = clean value. 1 = questionable value. See "Technical Validation" section of the MacroSheds data paper for details.
ms_interp	Boolean integer. 0 = measured or imputed by primary source. 1 = interpolated by MacroSheds. See "Temporal Imputation and Aggregation" section of the MacroSheds data paper for details.
val_err	The combined standard uncertainty associated with the corresponding data point, if estimable. See "Detection Limits and Propagation of Uncertainty" section of the MacroSheds data paper for details.

Core time-series datasets generated by ms_load_product are in MacroSheds format.

Load methods:

• 'pw': period-weighted method, described in Aulenbach et al. 2016. Here, C is linearly interpolated. This option uses package RiverLoad.

• 'rating': AKA regression-model method, described in Aulenbach et al. 2016. This option uses package RiverLoad.

• 'composite': composite method, described in Aulenbach et al. 2016. This option uses package RiverLoad.

• 'beale': Beale ratio estimator, described in Meals et al. 2013. This option uses package RiverLoad.

• 'average': mean Q over the aggregation period times mean C over the aggregation period Consult Figure 10 in Aulenbach et al. 2016 for guidance on method selection. See Figure 1 for some intuition.

Output units are kg/ha/yr, where yr is water-year.

References:

• Aulenbach, B. T., Burns, D. A., Shanley, J. B., Yanai, R. D., Bae, K., Wild, A. D., Yang, Y., & Yi, D. (2016). Approaches to stream solute load estimation for solutes with varying dynamics from five diverse small watersheds. Ecosphere, 7(6), e01298.

• Meals, D. W., Richards, R. P., & Dressing, S. A. (2013). Pollutant load estimation for water quality monitoring projects. Tech Notes, 8, 1-21.

Value

A list containing two tibbles, load and diagnostics. Tibble formats are as follows.

load: a tibble of annual loads.

column	definition
site_code	short name for MacroSheds site. See MacroSheds format below.
var	Variable code. See MacroSheds format below.
water_year	Full year beginning on October 1 and ending on Sept 30
load	Annual solute load for the watershed
method	The method used to compute annual solute load. See Aulenbach et al. 2016 and Gubbins et al. in review
ms_recommended	The most appropriate load estimation method based on Fig 10 from Aulenbach et al. 2016 and Fig 16 from Gubbins et al. in review. 1 = recommended, 0 = not recommended. NA = insufficient data to generate meaningful load estimate by the corresponding method.

Output units are kg/ha/yr, where yr is water-year.

diagnostics: a tibble of quantities that may be used to filter load estimates. Aulenbach et al. 2016 and Gubbins et al. in review.

column	definition
site_code	short name for MacroSheds site. See MacroSheds format below.
var	Variable code. See MacroSheds format below.
water_year	Full year beginning on October 1 and ending on Sept 30
cq_rsquared	The coefficient of determination from the concentration-discharge relationship
cq_resid_acf	Autocorrelation coefficient at lag 1 on the residuals of the concentration-discharge relationship
c_acf	Autocorrelation coefficient at lag 1 for the concentration series
n_c_obs	Number of concentration observations
n_q_obs	Number of discharge observations
n_paired_cq_obs	Number of paired concentration and discharge observations
unique_c_quarters	Number of unique quarters (even divisions of the calendar year into four parts) represented in the concentration data
ws_area_ha	The watershed area in hectares

Author(s)

Wes Slaughter, [e-mail]

Nick Gubbins, [e-mail]

Mike Vlah, [e-mail]

Spencer Rhea

See Also

ms_calc_flux()

Examples

ms_root = 'data/macrosheds'
ms_download_core_data(macrosheds_root = ms_root,
                      domains = 'hbef')
chemistry <- ms_load_product(macrosheds_root = ms_root,
                             prodname = 'stream_chemistry',
                             site_codes = c('w1', 'w3'),
                             filter_vars = c('NO3_N', 'Cl'))

q <- ms_load_product(macrosheds_root = ms_root,
                     prodname = 'discharge',
                     site_codes = c('w1', 'w3'))

flux <- ms_calc_load(chemistry = chemistry,
                     q = q)

MacroSHEDS/macrosheds documentation built on Oct. 30, 2024, 11:15 a.m.