“…TE is determined as:
where w i , l i and d i are channel width, length, and depth in meters of link i , k i is the first order removal rate constant of nitrate estimated from literature based on spatially referenced regressions of contaminant transport on watershed attributes (SPARROW) regression (Alexander et al.,
2000; Howarth et al.,
1996; Smith et al.,
1997), θ T− 20 is a simplified temperature‐dependent expression of the Arrhenius equation (Ambus,
1993; Boyer et al.,
2006; Chapra,
1997) for observed values of temperature ( T ) at the delta apex (Holmes et al.,
2012) in units of centigrade and expresses the temperature dependence of biologically mediated reactions across seasons and climate (Table 1). We express the aggregate effect of removal processes (e.g., denitrification, and plant uptake) and processes that add nitrate (e.g., nitrification) as a loss rate since removal processes often outweigh regeneration in estuarine environments (Delaune et al.,
2005; Howarth et al.,
1996; Seitzinger et al.,
2006) including high latitude streams (Bergstrom et al.,
2020; Blaen et al.,
2014; Gooseff et al.,
2004). Because the major mechanisms controlling in‐stream removal of nitrogen operate at the channel bed or hyporheic zone, deeper streams are modeled using lower magnitudes of processing rates, that is, k in Equation (Table 1; Howarth et al.,
1996; Smith et al.,
1997; Alexander et al.,
2000; Howarth et al.,
1996; Smith et al.,
1997).…”