Upland Microtopography and Implications to Surface Water Detention in Maine
Abstract
A notable characteristic of Maine's forested landscape is the microtopography caused by a combination of factors related to surficial geology and tree fall. These features are often on the scale of single meters wide and decimeters to a meter in depth, appearing as "puddles" in the landscape during intense or high magnitude precipitation events. The surface water detention provided by the depressions can be substantial at the scale of a watershed and measurably affect runoff rates in low order streams. Generalized ranges for surface water storage capacity have been summarized in textbooks for varied landscape conditions, but little is known about how microtopography and related detention varies in Maine's dominant physiographic settings defined by slope, surficial geology, and land cover conditions. With the increasing availability of high resolution elevation data, it has become possible to remotely evaluate the extent of these depressions and quantify the total upland storage capacity they may represent.
In this poster we describe and quantify microtopography in several Maine settings using measurements of hillslope topographic position and depression volume. We then relate the distribution of microtopography to diverse landform and land use conditions. Spatial and temporal variations in these microtopographic patterns, particularly those with anthropogenic causes, have significant regional implications for runoff generation and habitat use; in one study watershed, conversion of land from forest to grassland cover resulted in an 80+% reduction in potential surface detention volume. For our analysis, we use LiDAR data from several Maine coastal and inland watersheds: Webhannet River in Wells; Darling Marine Center campus in Walpole; an unnamed stream on Marsh Island in Orono; Cromwell Brook on Mount Desert Island; Bear Brook on Lead Mountain in East Hancock; and Thomas Pond in Casco/Raymond, for which both 1m and 2m LiDAR are available, allowing us to examine the effect of DEM resolution on analysis results.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H23N2157V
- Keywords:
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- 1804 Catchment;
- HYDROLOGYDE: 1836 Hydrological cycles and budgets;
- HYDROLOGYDE: 1874 Ungaged basins;
- HYDROLOGY