TY - JOUR
T1 - Comparison of simulated water, nitrate, and bromide transport using a Hooghoudt-based and dynamic drainage model
AU - Mollerup, Mikkel
AU - Abrahamsen, Per
AU - Petersen, Carsten Tilbæk
AU - Hansen, Søren
PY - 2014/2
Y1 - 2014/2
N2 - For large-scale hydrological modeling, the accuracy of the models used is a trade-off with the computational requirements. The models that perform well on the daily/meter scale may not perform well when applied at the yearly/kilometer scale. We compare two models of water flow and nitrate and bromide transport in a tile drained soil. The first model is based on a 2-D grid with an explicit drain node, here called the Dynamic Drainage Model (DDM). The second and less computationally expensive model is based on an 1-D vertical discretization where the horizontal flow is included as a sink term based on the Hooghoudt theory, here called the Hooghoudt Drainage Model (HDM). Both are based on Finite Volume Method solutions to Richard's equation and to the advection-dispersion equation (ADE), and embedded within the Daisy agroecological model, which includes the nitrogen cycle. The two models are run with 10 years of weather data and three different lower-boundary conditions. Losses of water, nitrogen, and bromide to both drain pipes and deep percolation/leaching are compared between the models, at daily and yearly time scales. In no case do we find the discrepancy large enough to warrant a rejection of the use of the faster HDM instead of DDM. For the daily time scale, we find in general a higher Nash-Sutcliffe efficiency coefficient for water (0.98-1.00) than for nitrate (0.97-1.00), and the lowest for bromide (0.95-1.00). The results are explained with a low concentration gradient along the water flow pathway toward the drain. Key Points Using 1-D and 2-D simulations, we simulate drainage of water, bromide, and nitrate On a yearly time scale, 1-D and 2-D simulation results for drainage are comparable On a daily time scale, 1-D and 2-D simulation results for drainage are comparable
AB - For large-scale hydrological modeling, the accuracy of the models used is a trade-off with the computational requirements. The models that perform well on the daily/meter scale may not perform well when applied at the yearly/kilometer scale. We compare two models of water flow and nitrate and bromide transport in a tile drained soil. The first model is based on a 2-D grid with an explicit drain node, here called the Dynamic Drainage Model (DDM). The second and less computationally expensive model is based on an 1-D vertical discretization where the horizontal flow is included as a sink term based on the Hooghoudt theory, here called the Hooghoudt Drainage Model (HDM). Both are based on Finite Volume Method solutions to Richard's equation and to the advection-dispersion equation (ADE), and embedded within the Daisy agroecological model, which includes the nitrogen cycle. The two models are run with 10 years of weather data and three different lower-boundary conditions. Losses of water, nitrogen, and bromide to both drain pipes and deep percolation/leaching are compared between the models, at daily and yearly time scales. In no case do we find the discrepancy large enough to warrant a rejection of the use of the faster HDM instead of DDM. For the daily time scale, we find in general a higher Nash-Sutcliffe efficiency coefficient for water (0.98-1.00) than for nitrate (0.97-1.00), and the lowest for bromide (0.95-1.00). The results are explained with a low concentration gradient along the water flow pathway toward the drain. Key Points Using 1-D and 2-D simulations, we simulate drainage of water, bromide, and nitrate On a yearly time scale, 1-D and 2-D simulation results for drainage are comparable On a daily time scale, 1-D and 2-D simulation results for drainage are comparable
U2 - 10.1002/2012wr013318
DO - 10.1002/2012wr013318
M3 - Journal article
SN - 0043-1397
VL - 50
SP - 1080
EP - 1094
JO - Water Resources Research
JF - Water Resources Research
IS - 2
ER -