Coupling hydrologic and hydraulic models in the Mackenzie Basin to quantify the spatial and temporal distribution of surface and subsurface water storages
Abstract
In this study, the Hillslope River Routing (HRR) model is used to route surface and subsurface runoff from the Community Land Model (CLM) version 4 in the Mackenzie River Basin for the period 2000-2004. The HRR model simulates lateral surface and subsurface runoff from hillslopes using kinematic wave methodologies, channel/floodplain discharge using diffusion wave routing and lake storage/discharge using modified pulse methodologies. The CLM model simulates vertical water and energy balance. The surface and subsurface runoff terms from the CLM model operating on a rectangular grid approximately 1 x 1.25 degree are remapped to the HRR model’s irregular computation grid. The HRR model uses a grid based on Pfafstetter sub-basins derived from landscape drainage patterns. The intent of the study is to quantify the spatial and temporal distribution of water storages throughout the basin using a combination of remote sensing, downscaling and modeling. By coupling vertical water balance and lateral routing models, it is possible to decompose the basin’s total water storage signal into sub-signals from key water stores and fluxes. For this application, the Mackenzie Basin is discretized to Pfafstetter Level 4 (5,077 sub-basins) based on a drainage network derived from the ASTER dem. The HRR model further approximates each sub-basin as an open book with two hillslopes draining laterally to the channel network. At this scale, the median hillslope land area is 140 sq km (ranging from 1 ha to 10,000 sq km) with a flow length of 3.0 km (ranging from 25 m to 25 km). Presented here are preliminary model results compared to in-situ streamflow data and GRACE total water storage changes averaged over level 1 sub-basins (about 160,000 sq km). Additionally, the model provides at any given location in the basin, all water stores and fluxes integrated over the corresponding upstream drainage area are determined hourly (e.g., on 01 Jan 2003 at 01:00, the distribution of water is 5% surface runoff, 20% soil moisture, 10% shallow sub-surface runoff, 25% groundwater, 15% rivers/floodplains, 5% lakes, 10% snow). The coupled models will ultimately be used to assess the impacts of climate change (e.g., changes in permafrost) on water storage and river discharges throughout the basin.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFM.H41B1088B
- Keywords:
-
- 1823 HYDROLOGY / Frozen ground;
- 1847 HYDROLOGY / Modeling;
- 1850 HYDROLOGY / Overland flow;
- 1856 HYDROLOGY / River channels