Appendix E. Uncertainty assessment for groundwater input (GW).
(E.1) 
where was the mean precipitation, ET was the mean evapotranspiration, A_{w} was the groundwater recharge area, was the mean of measured groundwater DIN, DON, PN, and DIP concentrations, and A was the embayment area. Table E1 contains the parameter values, SE, and degrees of freedom for the values on the right side of Eq. E.1.
and associated SE and df were calculated as described in Appendix C. ET was calculated as the mean of minimum and maximum values of ET from southeastern coastal watersheds reported in the literature. SE_{ET} was calculated from Eq. 2. As minimum and maximum values were used to estimate the SE, its df approach infinity and were arbitrarily set to 1000. A_{w} was calculated as the mean of the minimum and maximum watershed area with SE calculated from Eq. 2. Similar to the df for ET, df for A_{w} approach infinity and were arbitrarily set to 1000. was calculated by Eq. 2 with df = n–1. Calculations of A and the SE and df for A are described in Appendix A.
The SE_{GW} and df_{GW} were calculated from Eqs. 3 and 7, respectively, based on the GW formulation (Eq. E.1) where:
(E.2) 

(E.3) 
TABLE E1. Parameter values used in groundwater (GW) input calculations. was the mean precipitation, ET was the mean evapotranspiration, A_{w} was the groundwater recharge area, were the mean groundwater nutrient concentrations, and A was the embayment area. SE and df were the standard error and degrees of freedom, respectively.
Parameter 
Constituent 
Value 
SE 
df 
(m/y) 
– 
1.44 
0.02 
1.0 
ET (m/y) 
– 
1.15 
0.15 
1000 
A_{w} (m^{2}) 
– 
14434 
3042 
1000 
(mmoles/m^{3}) 
20.9 
7.9 
13.0 


73.7 
8.0 
8.0 


0.9 
0.5 
13.0 

A (m^{2}) 
– 
9841 
27.7 
799 