Starting with base data layers of NHDPlus, SSURGO, impervious surface, flow
velocity, and time of travel, this function calculates percentage of Nitrogen
removal. Nitrogen removal methods and calculations are from
Kellogg et al. (2010).
This function assumes data has been downloaded with
nsink_get_data and has been prepared with
nsink_prep_data.
Usage
nsink_calc_removal(
input_data,
off_network_lakes = NULL,
off_network_streams = NULL,
off_network_canalsditches = NULL
)Arguments
- input_data
A list of input datasets created with
nsink_prep_data.- off_network_lakes
Optional argument to set removal for waterbodies that are not part of the NHDPlus hydrologic network. Default value is to use the 75th percentile of removal from other lakes in the HUC. If another value is desired provide a single numeric ranging from 0 to 1.
- off_network_streams
Optional argument to set removal for streams that are not part of the NHDPlus hydrologic network. Default value is to use the median removal from first order streams in the HUC. If another value is desired provide a single numeric ranging from 0 to 1.
- off_network_canalsditches
Optional argument to set removal for canals and ditches that are not part of the NHDPlus hydrologic network. Default value is to use the 25th percentile of removal from third order streams in the HUC. If another value is desired provide a single numeric ranging from 0 to 1.
Value
A list with three items, 1) a raster stack with one layer with the nitrogen removal, a second layer with the type of removal (e.g. hydric soils, lakes, streams), 2) a polygon representing removal from land, and 3) a polygon representing removal from the stream network, including stream removal, and lake removal.
References
Kellogg, D. Q., Gold, A. J., Cox, S., Addy, K., & August, P. V. (2010). A geospatial approach for assessing denitrification sinks within lower-order catchments. Ecological Engineering, 36(11), 1596-1606. Link
Examples
if (FALSE) {
library(nsink)
niantic_huc <- nsink_get_huc_id("Niantic River")$huc_12
niantic_data <- nsink_get_data(niantic_huc, data_dir = "nsink_data")
aea <- 5072
niantic_nsink_data <- nsink_prep_data(niantic_huc, projection = aea ,
data_dir = "nsink_data")
removal <- nsink_calc_removal(niantic_nsink_data)
}