TY - JOUR
T1 - Surface runoff in flat terrain
T2 - How field topography and runoff generating processes control hydrological connectivity
AU - Appels, Willemijn M.
AU - Bogaart, Patrick W.
AU - van der Zee, Sjoerd E.A.T.M.
PY - 2016/3/1
Y1 - 2016/3/1
N2 - In flat lowland agricultural catchments in temperate climate zones with highly permeable sandy soils, surface runoff is a rare process with a large impact on the redistribution of sediments and solutes and stream water quality. We examine hydrological data obtained on two field sites in the Netherlands for a period of 1.5 years to give an integrated narrative of surface runoff in this type of catchment. In the monitoring period, seven surface runoff events were observed with a magnitude of 9.8-975 L runoff. Four of these events were classified as saturation excess events, due to a shallow water table. Three of the events occurred under infiltration excess conditions due to rainfall in combination with snowmelt. Though the microtopography of the fields was quite different, they were identical in terms of topographical indicators. Therefore, we analyzed the dynamics of hydrological connectivity on these fields with a numerical model that takes into account routing variability through microtopography and calculated simplified hydrographs and Relative Surface Connection functions from the results. The connectivity dynamics of the fields were different as quantified by these indicators. We found that the dynamics of hydrological connectivity in this low-angle terrain are not just a function of the soil surface meso- and microtopography, but also of the type of surface runoff generating process. This is an important factor to consider when using connectivity functions as an upscaling tool in catchment scale modeling.
AB - In flat lowland agricultural catchments in temperate climate zones with highly permeable sandy soils, surface runoff is a rare process with a large impact on the redistribution of sediments and solutes and stream water quality. We examine hydrological data obtained on two field sites in the Netherlands for a period of 1.5 years to give an integrated narrative of surface runoff in this type of catchment. In the monitoring period, seven surface runoff events were observed with a magnitude of 9.8-975 L runoff. Four of these events were classified as saturation excess events, due to a shallow water table. Three of the events occurred under infiltration excess conditions due to rainfall in combination with snowmelt. Though the microtopography of the fields was quite different, they were identical in terms of topographical indicators. Therefore, we analyzed the dynamics of hydrological connectivity on these fields with a numerical model that takes into account routing variability through microtopography and calculated simplified hydrographs and Relative Surface Connection functions from the results. The connectivity dynamics of the fields were different as quantified by these indicators. We found that the dynamics of hydrological connectivity in this low-angle terrain are not just a function of the soil surface meso- and microtopography, but also of the type of surface runoff generating process. This is an important factor to consider when using connectivity functions as an upscaling tool in catchment scale modeling.
KW - Hydrological connectivity
KW - Meso- and microtopography
KW - Overland flow
UR - http://www.scopus.com/inward/record.url?scp=84961355984&partnerID=8YFLogxK
U2 - 10.1016/j.jhydrol.2016.01.021
DO - 10.1016/j.jhydrol.2016.01.021
M3 - Article
AN - SCOPUS:84961355984
SN - 0022-1694
VL - 534
SP - 493
EP - 504
JO - Journal of Hydrology
JF - Journal of Hydrology
ER -