| Abstract: | Topographic shape is a watershed attribute thought to influence the flow path followed by water as it traverses a catchment. Flow path, in turn, may affect the chemical composition of surface waters. Topography is quantified in the hydrological model TOPMODEL as the relative frequency distribution of the index ln( a tanB), where a is the upslope area per unit contour that drains past a point and tanB is the local surface slope. Spatial distributions of ln( a tanB) were calculated for eight catchments in Wales on a 25 m ?? 25 m grid. Among the catchments, mean observed stream H+ concentration during high flow periods was highly correlated with the mean of the ln( a tanB) distribution. The steady-state gain of a transfer function (time series) model relating H+ to discharge was positively correlated with the mean of the ln( a tanB) distribution. These results suggest that during high flow periods, both the average stream acidity and the magnitude of fluctuations in H+ are conditioned by the topographic shape of the catchment. By performing a sensitivity analysis on TOPMODEL, we also show that as the mean of the ln( a tanB) distribution for a catchment increases, so does its theoretical likelihood to produce significant quantities of surface and near-surface runoff. Our observed results in the Llyn Brianne catchments are consistent with this theoretical expectation in that surface or near-surface runoff is often higher in acidity than are deeper sources of hillslope runoff. ?? 1990. |
| Genre: | Article |
| ProdID: | 70016257 |
| Citation Author: | Wolock, D. M.; Hornberger, G. M.; Musgrove, T. J. |
| Citation Contributing Office: | |
| Citation Datum: | |
| Citation Day: | |
| Citation Edition: | |
| Citation Editor: | |
| Citation End Page: | 259 |
| Citation Issue: | 1-4 |
| Citation Keywords: | |
| Citation Language: | English |
| Citation Larger Work Title: | Journal of Hydrology |
| Citation LatN: | |
| Citation LatS: | |
| Citation LonE: | |
| Citation LonW: | |
| Citation Month: | |
| Citation No Pagination: | |
| Citation Number Of Pages: | 17 |
| Citation Online Only Flag: | |
| Citation Phsyical Description: | |
| Citation Projection: | |
| Citation Public Comments: | |
| Citation Publisher: | |
| Citation Series: | |
| Citation Series Code: | |
| Citation Series Number: | |
| Citation Search Results Text: | Topographic effects on flow path and surface water chemistry of the Llyn Brianne catchments in Wales; 1990; Article; Journal; Journal of Hydrology; Wolock, D. M.; Hornberger, G. M.; Musgrove, T. J. |
| Citation Start Page: | 243 |
| Citation Volume: | 115 |
| Citation Year: | 1990 |
| Type: | citation/reference |
| Text: | Topographic effects on flow path and surface water chemistry of the Llyn Brianne catchments in Wales; 1990; Article; Journal; Journal of Hydrology; Wolock, D. M.; Hornberger, G. M.; Musgrove, T. J. |
| URL (THUMBNAIL): | http://pubs.er.usgs.gov/thumbnails/outside_thumb.jpg |
| Date Other: | Mon, 1 Jan 1990 00:00 -0600 |
| Publisher: | |
