Abstract
Abstract. Topography is a fundamental input to hydrologic models critical for generating realistic streamflow networks as well as infiltration and groundwater flow. Although there exist several national topographic datasets for the United States, they may not be compatible with gridded models that require hydrologically consistent digital elevation models (DEMs). Here, we present a national topographic dataset developed to support gridded hydrologic simulations at 1 km and 250 m spatial resolution over the contiguous United States. The workflow is described step by step in two parts: (a) DEM processing using a Priority Flood algorithm to ensure hydrologically consistent drainage networks and (b) slope calculation and smoothing to improve drainage performance. The accuracy of the derived stream network is evaluated by comparing the derived drainage area to drainage areas reported by the national stream gage network. The slope smoothing steps are evaluated using the runoff simulations with an integrated hydrologic model. Our DEM product started from the National Water Model DEM to ensure our final datasets will be as consistent as possible with this existing national framework. Our analysis shows that the additional processing we provide improves the consistency of simulated drainage areas and the runoff simulations that simulate gridded overland flow (as opposed to a network routing scheme). The workflow uses an open-source R package, and all output datasets and processing scripts are available and fully documented. All of the output datasets and scripts for processing are published through CyVerse at 250 m and 1 km resolution. The DOI link for the dataset is https://doi.org/10.25739/e1ps-qy48 (Zhang and Condon, 2020).
Highlights
Topography is one of the most important inputs to hydrologic simulations; it defines watershed boundaries and shapes river networks
Our goal is to start from these datasets to develop a national topographic dataset that is as consistent with these products as possible but is designed for gridded overland flow simulation
Because we are starting from established elevation models (DEM for National Water Model (NWM) V1.2), our evaluation is focused on the hydrologic improvements to the dataset
Summary
Topography is one of the most important inputs to hydrologic simulations; it defines watershed boundaries and shapes river networks. In addition to shaping surface flow networks, groundwater fluxes and residence times are strongly driven by topographic gradients (e.g., Condon and Maxwell, 2015). It is well established that topographic datasets require processing to be suitable for hydrologic simulation because flow networks and slopes can be sensitive to noise in the DEM and can be affected by the resolution and spatial gridding of a DEM (Habtezion et al, 2016; Sørensen and Seibert, 2007; Thompson et al, 2001; Vaze et al, 2010; Wolock and McCabe, 2000; Wu et al, 2008; Zhang and Montgomery, 1994) This processing generally consists of some combination of steps to (1) remove erroneous local minima that impeded flow (Kenny et al, 2008; Lindsay, 2016a, b); (2) lower or “burn” in the drainage network to ensure that flow occurs along identified stream segments (Lindsay, 2016b; Woodrow et al, 2016), and (3) smooth the DEM to remove noise introduced by the sampling resolution (Gallant, 2011; Lindsay et al, 2019)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
